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• v.11(41); 2021 Jul 19

Microbial diversity in full-scale water supply systems through sequencing technology: a review

College of Environmental Science and Engineering, Tongji University, Shanghai 200092 China, nc.ude.ijgnot@ztkywl321

State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 China

Jiping Chen

Zhongqing wei.

Fuzhou Water Affairs Investment Development Co., Ltd., Fuzhou 350000 Fujian China

Longcong Gong

Fuzhou Water Co., Ltd., Fuzhou 350000 Fujian China

The prevalence of microorganisms in full-scale water supply systems raises concerns about their pathogenicity and threats to public health. Clean tap water is essential for public health safety. The conditions of the water treatment process from the source water to tap water, including source water quality, water treatment processes, the drinking water distribution system (DWDS), and building water supply systems (BWSSs) in buildings, greatly influence the bacterial community in tap water. Given the importance of drinking water biosafety, the study of microbial diversity from source water to tap water is essential. With the development of molecular biology methods and bioinformatics in recent years, sequencing technology has been applied to study bacterial communities in full-scale water supply systems. In this paper, changes in the bacterial community and the influence of each treatment stage on microbial diversity in full-scale water supply systems are classified and analyzed. Microbial traceability analysis and control are discussed, and suggestions for future drinking water biosafety research and its prospects are proposed.

Drinking water microbial diversity influence in full-scale water supply systems.

Introduction

Water security is not only an ecological and environmental issue, but also an economic, social, and political issue that is directly related to national security. Safe drinking water is essential to public health and an integral part of effective policies to protect health. 1 However, as of 2017, billions of people worldwide still do not have access to safe drinking water and basic health services. According to the World Health Organization (WHO), 80% of human diseases and 50% of child deaths worldwide are related to drinking water quality. With the outbreak of COVID-19, the safety of microorganisms in the environment, especially in water, has become a greater concern. 2–4 Unlike chemical pollution, microbial pollution is proliferative, secondary, and infectious. The explosive proliferation of microorganisms can result in deterioration of water quality, and the presence of odor or toxins, 5,6 and induce secondary pollution. Water-mediated pathogenic microorganisms can be transmitted through diet, aerosols, and contact, endangering human health.

Culture-based methods are one of the most widely used traditional analytical approaches to evaluate the microbiological quantity of drinking water. However, due to the overlooked of some bacteria ( e.g. , viable but non-culturable (VBNC) bacteria), the culture-based method leads to an underestimation of the microbial density and diversity in drinking water. 7 As a result, nucleic acid-based approaches have been widely applied in recent investigations of drinking water distribution system (DWDS) microbial communities. 8,9 These culture-independent methods, such as sequencing technology, include internal transcribed spacer (ITS) fingerprints, terminal restriction fragment length polymorphisms (T-RFLP), 16S rRNA gene surveys, and metagenomics surveys, 10 which could not only detect low concentrations of microorganism (including VBNC), but also obtain microbial diversity information, providing a good technical support for the study of microbial fate.

Given the advantages, sequencing technology, especially high-throughput sequencing (HTS), is widely used to analyze microbial diversity in drinking water to obtain a more comprehensive understanding of bacterial ecology. This review paper summarize the findings of microbial community analysis in full-scale water supply system through sequence technology, especially from the perspective of biological safety of the tap water through distribution system, focusing on (i) the development of sequencing technologies and influence on the study the microorganism in water supply system; (ii) the microbial diversity and environmental impact on full-scale water supply systems using sequencing technology; (iii) evaluation of microbial safety in water source, water treatment process as well as the drinking water distribution system (DWDS); and (iv) proposed biosafety assurance measures for a full-scale water supply system. The goals of this review are to understand application of sequencing technology in the study of drinking water microbial communities, analyze the possible causes of microorganism safety problems in full-scale water supply systems, guide operational practices to obtain safe drinking water, and enhance future research on the drinking water microbiome.

Development of sequencing technology and its contribution to drinking water investigation

Development of sequencing technology.

Gene sequencing technology has developed in the last 50 years as a result of the pioneering Sanger and Coulson chain termination method. With the high cost and low throughput of first-generation sequencing technology, 11 continuous technological development and improvement yielded Roche's 454 technology, Illumina's Solexa technology, and ABI's Solid technology. The comparison of four generation sequencing technologies was list in Table 1 . Compared with first-generation Sanger sequencing, they offered high throughput 12 and fast sequencing, greatly reducing sequencing cost and expanding the scale of genomics research. 13 The timeline and comparison of commercial HTS instruments and costs since 2003 are shown in Fig. 1 . After the introduction of the Genome Sequencer 20 System by 454 Life Sciences in 2005, and the Genome Analyzer II by Illumina/Solexa in 2006, high-throughput sequencing companies were emerging, providing a solid foundation for the development of high-throughput sequencing and price reduction. However, second-generation sequencing technology was still costly, with a short-read length. Since 2008, single-molecule real-time (SMRT, PacBio) sequencing technology and the Heliscope (Helicos Biosciences) genetic analysis system have been developed, known as third-generation sequencing. In NGS method, DNA is broken into short pieces, amplified, and then sequenced. Third generation technologies do not break down or amplify the DNA: they directly sequence a single DNA molecule. Fourth-generation sequencing technology ( e.g. , Nanopore sequencing technology by Oxford Nanopore Technologies) was invented in 2014. 14 However, third- and fourth-generation sequencing technologies have relatively lower accuracy and have not been widely used as NGS. Currently, NGS technology is still the predominant sequencing technology in the market. The launch of Illumina's NovaSeq 6000 in 2017 brought the cost of sequencing under $100 per human genome, promoting widespread use of HTS in recent years in medicine, health, and environmental fields ( Fig. 1 ).

Sequencing technology application in water supply system

With the development of sequencing technology, especially high-throughput technology in recent years, analysis of drinking water microorganisms in relation to human health has been widely conducted. 15 As the analysis method has gradually shifted from traditional analytical approaches to sequencing analysis methods, the research and focus on the whole process of microorganisms in drinking water has also changed from the original quantity and species to the present diversity, transformation, and function. Searching related papers on the topic of “Water” and “Bacterial community” in Web of Science, the number of publications has reached 39540 (as of July 1, 2021), among which the number of annual increased papers reached more than 1000 since 2007. Searching related papers on the Web of Science with the topic of “Drinking Water” and “Bacterial Community”, the article number has reached 2708 (as of July 1, 2021), among which the growth rate of the increased papers number was largely improved from 2006 ( Fig. 2 ).

Here in this paper, the changes in microbial diversity from source water to tap water were categorized based on reported research which using sequencing technologies, as well as the health risks associated with these changes.

Impact on microbial diversity in full-scale water supply system

Water source effects, biological effects.

Although the microbial community changes during water treatment, especially in biological and disinfection processes, most microorganisms in drinking water are introduced from those in source water. The diversity of microorganisms in the source water directly affects the species of microorganisms in the drinking water. 16 Different water sources have different microbial community compositions, resulting in different bacterial communities in the final tap water. 17–21 Microbial communities are sensitive to changes in their environment and reflect the structure and function of aquatic ecosystems. However, due to the influence of upstream water input and water environment, changes in the water source microbial community are complicated. 22 The dominant microbial composition may be similar in different water sources, but the abundances may vary. 17 Delphine, 18 Pearce 23 and Henne 24 found the same microbial compositions, Actinobacteria , Bacteroidetes , and Beta-proteobacteria , in different source waters, in proportions of 40.9%, 22.7%, and 18.2% (Sep Reservoir and Pavin Lake); 19%, 25%, and 26% (Sombre Lake); 16%, 25%, and 20% (two reservoirs in the south of Braunschweig), respectively. The results also showed that the predominant bacterial phyla were Actinobacteria , Proteobacteria , and Bacteroidetes , in reservoirs in Shanghai 22 and Hong Kong, 25 with proportions of 46%, 36.6%, and 16.1%; 24.55%, 45.72%, and 14.56%, respectively. Gomez-Alvarez et al. 21 investigated bacterial composition in a metropolitan DWDS using groundwater (GW) and surface water (SW); the results showed that the bacterial diversity of tap water from SW and GW service areas was different, indicating that different source water quality parameters and treatment processes can result in different microbial diversity in the final tap water. As the biological diversity of drinking water sources directly affects the microbial diversity in drinking water, many studies have focused on microbial diversity in drinking water sources and its environmental impacts.

Chemical effects

Environmental factors such as temperature, 25–27 pH, 28,29 electrolyte type, 19,30,31 salinity, 32 dissolved particles, 26 dissolved oxygen (DO), 33,34 C/N ratio, 19 total nitrogen (TN), 25 total phosphorus (TP), 22 and organic matter 35,36 have been investigated, and verified to influence the composition of the microbial community in drinking water. Zhang et al. 30 investigated the bacterial communities during the outbreak and decline of an algal bloom in a drinking water reservoir. The results indicated that the bacterial communities were significantly correlated with conductivity, ammonia nitrogen, water temperature, and Fe. Kaevska et al. 26 found that actinobacteria negatively correlated with phosphorus, sulfate, dissolved particles, and chloride levels. Proteobacteria positively correlated with sulfate, dissolved particles, chloride, dissolved oxygen, and nitrite levels. Jiang et al. 22 found that the relative abundance of predominant bacteria was affected by environmental factors in source water, and the changes in chemical oxygen demand (COD), TN, and TP in source water were related to microbial diversity. Seasonality also affects the microbial diversity of the source water. Wei et al. 25 found that in a drinking water source in Hong Kong, the microbial community composition and distribution exhibit obvious differences in the dry season and the rainy season, suggesting that seasonal change, as a comprehensive influencing factor, may have a great impact on the microbial diversity of drinking water sources.

Organics effects

As early as 1996, Pierre et al. 37 reported the threat of dissolved organic matter (DOM) in water to bacterial regeneration and water treatment. DOM is a mixture of common compounds in drinking water that can affect the optimization and efficiency of water treatment unit operations, including coagulation, sedimentation, and membrane treatment, and serve as the main precursor of disinfection byproducts (DBPs). 38 Nescerecka et al. 35 found that bacterial proliferation in chlorinated SW samples was restricted mainly by phosphorus and organic carbon; in chlorinated GW samples, carbon was the limiting factor. Apart from some nutrients or DBPs precursors of organic matter, some pharmaceutical and personal care products (PPCPs) which had been widely detected in aquatic environment, 39 influence the proliferation of bacteria, such as antibiotics, 40,41 and environmental endocrine disruptors (EEDs). 42,43 Antibiotics that can screen, enrich, and induce antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) largely affect the stability of microbial diversity, which is a major concern. Deng et al. 44 investigated the antibiotic distribution and microbial diversity in water sources; the results showed that areas polluted with high levels of antibiotics had rich and highly diverse bacterial communities. Ofloxacin posed the main risk to aquatic organisms; the antibiotics in 11.5% of the samples posed resistance selection risks. In recent years, with antibiotics in source water, the investigation of ARGs in full-scale water supply systems has increased, as they may affect the disinfection process in drinking water treatment plants (DWTPs), and the microbial diversity in DWDSs and in tap water. Guo et al. 20 investigated sul I , sul II , tet(C) , tet(G) , tet(X) , tet(A) , tet(B) , tet(O) , tet(M) , tet(W) , and 16S rRNA genes in seven DWTPs in the Yangtze River Delta in China. All the investigated ARGs were detected in the source waters of the seven DWTPs; sul I , sul II , tet(C) , and tet(G) were the four most abundant ARGs. The total concentration of the sulfonamide or tetracycline resistance gene class was greater than 10 5 copies per mL. Additionally, Wu et al. 36 studied the influence of disopyramide on bacterial diversity in water; the results showed that the community density and diversity decreased significantly after the addition of disopyramide. In addition, the microbial communities in drinking water sources are affected by antibiotics in water sources.

Unconventional water sources effects

In addition to SW and GW, in some areas of water shortage, rainwater, 45,46 and desalination water 47 are used as drinking water sources. For rainwater, researchers have used sequencing technology to study the microbial diversity of the water from these sources; the sequencing analysis indicated the presence of one or more fecal indicators, and potential bacterial and protozoan pathogens were detected in the roof-harvested rainwater (RHRW), suggesting that RHRW may not be suitable for drinking. Thus, improving the rainwater biosecurity was proposed through regularly cleaning roofs and gouges, pruning overhanging branches, and reducing the contamination of rainwater tanks by animal waste. For desalination water, the survival microbial pathogens are markedly reduced, especially when comminating with a high level of sunlight radiation. However, some pathogens, such as Vibrio cholerae , could still survive. Although most systems could remove the vast majority of microbial pathogens, in some circumstances, there is a significant potential for some pathogens transfer, 10 thus creates biosafety stress for subsequent processes. Hence, disinfection was recommended whenever possible in these water sources treatments.

The microbial diversity of water sources detected by sequencing technology were categorized in Table 2 . Microbial diversity in drinking water sources is influenced by environmental factors, including chemical factors (electrolytes, organics, pH, nutrients, antibiotics) and physical factors (temperature, seasonality, light irradiation). The microbial diversity in the source water also affects the chemical and physical characteristics of the water. In conventional treatment, the source water microbial community is important because it is the source, and the tap water microbial community is the sink ( Fig. 3 ). In studying the dynamic changes of microorganisms in water sources, physical, chemical, and biological properties must be considered together for systematic analysis to evaluate the microorganism diversity more comprehensively.

Drinking water treatment processes effects

Drinking water treatment is the key to preventing waterborne diseases and their spread. There is a potential relationship between bacterial community composition and the emergence of opportunistic pathogens; 48 problems encountered in drinking water treatment plants or water distribution may lead to the proliferation of conditioned pathogenic bacteria ( Mycobacterium , Pseudomonas aeruginosa , Legionella pneumophila , etc. ). 49–51 Currently, conventional water treatment processes (coagulation–flocculation, sedimentation, filtration, and disinfection) are widely used to purify drinking water in China. 52 In recent years, with the deterioration of source water quality, especially from an increase in organic matter, advanced treatment technologies such as ozone–biological activated carbon (O 3 –BAC) and membrane treatment have been applied. Understanding changes in the microbial community during treatment is vital for the management of DWTSs. Usually, O 3 –BAC and disinfection processes are regarded as the primary units influencing the microbial density and diversity; other units also have some influence. 53 A great change in the proportions of Actinobacteria , Proteobacteria , and Firmicutes during the treatment process was detected by Hou et al. , the proportion of Actinobacteria decreased sharply, and the proportions of Proteobacteria and Firmicutes increased and predominated in treated water. 54 During drinking water treatment processes, the microbial activity and bacterial diversity showed obvious spatial differences; the bacterial community changed significantly after chlorination disinfection, indicating that the disinfection process affected the bacterial community. In addition, the bacterial community structure of the finished water was like that of the biofilm on the GAC, indicating that the application of biological treatment technology can significantly change the microbial community composition inherited from the source.

Coagulation and sedimentation

Coagulation and sedimentation are the most common processes in water treatment systems to remove microorganisms, such as protozoa ( e.g. , giardia and crypto) and prokaryotes ( e.g. , cyanobacteria and bacteria). Here, we'll focus on the effects of the treatment on bacteria. With double electric layer compression, adsorption electric neutralization, adsorption bridging, and sediment trapping, the particulate matter and colloids, and the bacteria adhered to them, are removed from the source water. These processes are generally reported to have no obvious effect on the microbial community structure. 55,56 However, by monitoring the microbial density and diversity from the influent and effluent of each unit in the water treatment process, Hou et al. 54 found that each unit in the DWTP had an influence on microbial diversity. The removal of microorganisms from water by coagulation and clarification mostly refers to microorganisms that are easily adsorbed on suspended particles and colloids. Strengthening coagulation can greatly reduce the pressure of follow-up disinfection, reducing the cost of follow-up treatment, and reducing the generation of DBPs. Thus, the coagulation and sedimentation process must be considered for microbial safety assurance.

Filtration ( e.g. , sand filtration, microfiltration, GAC filtration, and BAC filtration) usually occurs after coagulation and sedimentation; its main function is to intercept the macromolecular solid particles and colloids in water. Filtration is used to remove the suspended matter that has not been removed by coagulation and sedimentation. With good adsorption and interception capability, the filtration process can significantly reduce suspended substances such as bacteria and viruses, further affecting the microbial diversity. 57,58 In addition, various biological processes ( e.g. , biofilm formation and shedding) can occur in filters, which could further affect the microbial community structure of the effluent. Bai et al. 59 verified that sand filtering produces a biofilm on the sand that can influence the water quality and microbial diversity. Shaw et al. 57 reported that microfiltration (MF) treatment is the most effective way to inhibit biofilm growth in a DWDS, and that a highly efficient post-treatment disinfection regime reduces the rate of post-treatment regrowth compared with conventional treatment. By investigating the metagenomic characterization of three biofilters (rapid sand filter, GAC filter, and slow sand filter) in a full-scale DWTP, Oh et al. found that the bacterial communities in biofilters were significantly different from those in source water and effluent; Bradyrhizobiaceae were abundant in GAC, whereas Nitrospira were enriched in the sand filters. The GAC community was enriched with functions associated with aromatic degradation, many of which were encoded by Rhizobiales . 60 Lee et al. 61 used q-PCR analysis to clarify ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) effects on ammonium oxidation in a pilot scale rapid sand filter system, the results showed that AOA and AOB were similar in abundance and AOB density set the observed ammonium removal rate. The results were consistence with Tatari et al. , 62 and they also put forward that Nitrospira should be the predominant NO 2 oxidizers. And rapid sand filters are microbially dense, with varying degrees of spatial heterogeneity, leading to in different results, even under very similar experimental setup. In GAC sand filter system, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium , Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes. 63 Coincidentally, LaPara et al. 64 also found that AOB were prominent in the bacterial communities, and he most prominent population in the profiles was a Nitrospira spp., representing 13 to 21% of the community. By determining the composition of the bacterial community after the stable operation of biological activated carbon (BAC) particles, Zhang et al. 65 found that after nine months of operation, a stable bacterial community dominated by bacteria such as Pseudomonas sp., Bacillus sp., and Nitrospira sp. could effectively eliminate or reduce 41 chemicals in water.

O 3 –BAC

When the organic matter in the source water cannot be effectively removed using conventional processes such as coagulation, clarification, and filtration, advanced treatment technology, O 3 –BAC, is often used to minimize the precursor of disinfection byproducts. 66 However, with the removal of organic matters in DWTP, the leakage of bacteria which could be have been seeding of distribution system, becomes an important issue in this unit. Researchers have increasingly studied microbial diversity changes in the O 3 –BAC unit to determine which microbial consortia colonize filters and what metabolic capacity they possess to obtain the organic matter removal mechanism, based on excellent organic matter removal performance. The influent water quality, oxidative pretreatment, empty bed contact time (EBCT), and backwashing frequency can affect the redox environment of the system, influencing the microbial diversity of the effluent. 71,72 Soonglerdsongpha et al. 73 compared the O 3 –BAC effect on assimilable organic carbon (AOC) removal in three DWTPs in Japan and found that AOC increased after O 3 treatment, and BAC could remove 53–73% of the AOC from water, which may be attributed to the microbial community differences. The results were consistent with Liao et al. , 74 who also showed that the BAC filtration system effectively removes both dissolved organic carbon (DOC) and AOC. 76 Researchers also investigated the effects of temperature, 77 influent water quality, 76 types of activated carbon, residence time, 59 filtration depth, and the backwash process of activated carbon 92 on the microbial community in the effluent during the operation of O 3 –BAC.

Disinfection

The disinfection process is the last barrier to ensure the biological safety of drinking water; its influence on microbial diversity is the greatest in the water treatment process, thus determining the microbial communities in the subsequent units. In recent years, however, chloride-resistant bacteria and VBNC have often been detected in finished water after disinfection, which could result in biofilm formation 78–80 and pipeline corrosion 81,82 in the subsequent DWDS. Thus, researchers have studied changes in the microbial community during the disinfection process, focusing mainly on improving the efficiency of disinfection and controlling costs. The results showed that disinfection (chlorination, chloramination, and hypochlorination) has a significant impact on microbial diversity, 83,84 decreasing bacterial diversity and cultivability, transferring the culturable bacteria from predominantly Gram-negative to predominantly Gram-positive. 93 After disinfection, alpha- and beta- proteobacteria were dominant in chlorinated water. Betaproteobacteria was more abundant after chloramine disinfection than the other two processes. The studies also revealed that the richness, diversity, and evenness of bacterial communities were greater in winter than in summer. 94 Chlorination and chloramination are the two main types of disinfection treatments applied to inactivate pathogens in DWTPs; the efficiency differs based on the disinfectant type and dosage. 85 Williams et al. 86 compared the bacterial diversity of drinking water in the distribution system after chlorination and chloramination, and found that even after disinfection, numerous bacteria still appeared in the finished water. Although the predominant species in the bacterial community were the same, the microbial diversity was different, which may be due to the difference in the inactivation mechanisms. 81 The presence of resistant bacteria can accelerate biofilm formation in a DWDS. Researchers have proposed a joint disinfection process 81,82,87 and develop new disinfectants for the removal of resistant bacteria. 88–90 In addition, ozone, a strong oxidant is widely used for water treatment, the effect was investigated by Kotlarz et al. , 95 and the results showed that with the detachment of biofilm, the cell concentration in water sample for sequential ozone chambers increased, and biofilms downstream of the dead zone contained a significantly higher relative abundance of bacteria of the genera Mycobacterium and Legionella than the upstream biofilm. Different from other disinfection method, UV, as a physical disinfection method, is a promising green method and have positive effect on disinfection process when combined with other disinfection method such as UV/Cl 2 , 96,97 UV/SO 3 2− , 98,99 and UV/H 2 O 2 . 97,100 Ao et al. 101 investigated the impact of UV treatment on microbial control in DWTPs, the results showed that UV treatment showed high efficacy in inactivating chlorine-resistant microorganisms, and can mitigate microbial re-growth to some extent. Proteobacteria (relative abundance: 8.02–92.34%) and Firmicutes (1.38–86.87%) were the dominant phyla in UV irradiation samples. Other common phyla included Bacteroidetes (1.38–15.26%) and Actinobacteria (0.16–8.87%).

Drinking water treatment processes effects on its microbiome was counted in Table 3 . Generally, drinking water treatment processes have a significant impact on the microbial diversity in tap water. Microbial changes, whether in the traditional processes of coagulation and sedimentation or in subsequent filtration and O 3 –BAC, are adjusted in the disinfection process, resulting in (i) the culturable bacteria transfer from predominantly Gram-negative to predominantly Gram-positive; 93 (ii) alpha- and betaproteobacteria are dominant in water; (iii) chlorine-resistant bacteria ( e.g. , VBNC and ARB) may be hidden dangers in subsequent DWDSs. The influence of each unit in the DWTP on the microbial community is shown in Fig. 4 . Coagulation and sedimentation have minimal influence on the community; filtration is the key step shaping downstream microbiota. The O 3 –BAC and disinfection processes have the strongest effect in changing the microbial community.

Influence in DWDS

Mathieu et al. 102 have reviewed the bugs systematically found in drinking water distribution systems all over the world (bacteria, viruses, yeasts, fungi, protozoa, microcrustaceans, rotifers, and oligochaete worms), here, we will analysis and discuss several factors which influence the microbial diversity in DWDS, especially the fate of biofilm on pipes according to the results from HTS. Based on the microbial diversity analysis of finished water and tap water, a diverse core microbiome was shared between the two locations; however, the microbial community was changed in the DWDS, 103 which was attributed to the shedding of biofilms (the environmental reservoirs for pathogenic microorganisms) from the inner wall of the pipe, posing a potential threat to human health. 104 Microbial regrowth with spatiotemporal variation is a major concern in distribution, as the physicochemical and nutritional conditions provided by pipe walls are very different from those found during treatment. Recent studies have identified the microbial community and dominant species associated with many factors in the DWDS. These factors include pipe materials, hydraulic conditioning, spatiotemporal effects, and the quality of the treated water ( Fig. 5 ).

Pipe materials

To date, the influences of the material and design of DWDS on the biofilm growth on pipe wall have been widely investigated, and these studies have been deepened step by step with the innovation of detection technology. Aggarwal et al. 80 put forward that coupon material (cement, HDPE, and PVC) did not have a significant impact on biomass levels or composition of the biofilm communities in the chloraminated reactors, however, most researchers have given evident on that pipe materials seem to be the most influential factor, followed by spatial and temporal distribution. The pipeline materials influence the density, the formation potential, the formation rate of biofilms, and the microbial diversity. When the biofilm is peeled off from the pipe into the bulk water, it directly affects the microbiome composition in the water. To date, research on the influence of pipe network materials on microbial diversity in drinking water and pipe wall biofilms has focused mainly on cast iron pipes (municipal pipes), 105,110,112 stainless steel (municipal pipe network into residential area), 116,117 EPDM and PEX (household plumbing material), 107,113,114 copper pipe (hotel hot water pipe), 108,109,114,117 and CP, PVC, and PVCF pipe (household common plastic pipe material). 105,110,112,116,117 The results showed that the biofilm community structure was different due to the pipe properties, especially for metal pipes. Due to the metal release, the biological diversity in different metal pipes was significantly different, with a greater biological diversity than in plastic materials. 115 Studies have also shown that the microbiome compositions of biofilms differ in different plastic pipeline materials. The most extensive biofilm was found in HDPE pipes; bacteria adhered to mineral deposits or were immersed in the extracellular polymeric substance (EPS). On the PEX surface, although the bacteria did not form large aggregates, the quantity of bacteria was the greatest. PVC biofilms do not contain mineral deposits, but are composed of single cells rich in Pseudomonas aeruginosa , which is harmful to human health. 106 Roeder et al. 107 found that the biofilm population had greater diversity on growth-supporting materials such as ethylene–propylene–diene monomer (EPDM) than on cross-linked polyethylene. Biofilms are mainly composed of proteobacteria; their composition is influenced by the applied materials. Liu et al. 105 reported that hyphomicrobia and corrosion-associated bacteria were the most dominant bacteria in PVC and cast iron biofilms, indicating that the colonization of bacteria on the material surface was selective. Mycobacterium and Legionella spp. are common potential pathogenic bacteria in biofilms; however, their proportions were different for PVC and cast-iron pipes. The results also verified that different pipe materials (PVC and cast-iron) have significant effects on the microbial community, especially the bacterial composition. Metal materials such as copper have an antibacterial effect, 109 which can significantly reduce the microbial diversity downstream. The proportion of bacteria and eukaryotes was reduced by half. 108 The effects of pipe materials on the drinking water microbiome are presented in Table 4 .

Hydraulic conditions

A previous study 118 reported no statistical difference in microbial communities in biofilms under different hydraulic conditions; biofilms were considered to be a substrate independent of the external environment. However, in bulk water, species richness and diversity were significantly greater in low hydraulic regimes, suggesting that water hydraulic conditions can influence the fate of biofilms. With further excavating to discover the formation mechanism of the biofilm, it was found that the hydraulic condition is related to the formation and shedding of the biofilm, and the water quality in the DWDS. 119 Thus, it has a great influence on the microbial community of the biofilm and bulk water. Boxall et al. 120 conducted a large number of studies revealing a tendency for greater species richness and diversity with highly varied flow. A more cohesive biofilm structure may be more resistant to external shear stress and detachment. In addition, the flow rate variation during growth was positively correlated with the number of cells, but negatively correlated with the EPS-to-cell volume ratio and bacterial diversity. 121 The results were consistent with E. Tsagkari's findings, which showed that turbulence could enhance the growth of drinking water biofilms. 122 Some studies have focused on water discoloration. It was believed that discoloration is influenced by hydraulic conditions, 121,123 and related to the biofilm shedding in water, indicating that the hydraulic condition plays an important role in the diversity of microbes in drinking water. Additionally, some researchers also argued that the strength of the biofilm matrix is not dictated by the applied fluid shear but is merely coincidental because the EPS composition and density are dictated by other purposes such as a defense from biocides or as a cache of stored food. Thus, one would not expect the strength to increase with fluid shear.

In studying the effects of time on the microbial diversity of drinking water, we considered short-term effects, such as water age or residence time, 124–126 and long-term effects, such as seasonal changes. 94,127,128 The results 112,129 showed that the residual chlorine and DO decreased with the age of the water; DOM, TOC, total bacterial count, and bacterial diversity increased. From the beginning to the end of the DWDS, the relative abundance of Rhizobium decreased, and the relative abundance of most other residues increased in varying degrees. Studies have also reported that a greater water age produces a greater relative presence of M. avium , which can increase the risk of human infection. 130 The results were consistent with those of Masters et al. 111 However, in some studies, the effect of water age was not significant. Hwang et al. 131 studied the water-like microbial community at five locations, indicating that at the sampling site and water age (<21.2 h), most of the time samples contained microbes. The composition had no significant effects.

Water stagnation

In contrast to municipal water supply systems, water stagnation is an important water supply system characteristic in buildings. In the urban water supply system, the flow in the urban area rarely stops completely due to the high-water demand. However, in buildings, water flow is often stopped for long periods of time, allowing long incubation times for bacteria, and enhancing the formation of biofilms on the inner walls of pipes. 125,132–135 Stagnation is still an issue in building design. Studying the effect of stagnation time can effectively guide the end-use of water to reduce the risk of microbial contamination. Green-building design often focuses on water conservation, which essentially prolongs water stagnation and accelerates the deterioration of water quality. 136,137 Studies have shown that the composition of the bacterial community changes dramatically, and the cell count increases by two orders of magnitude after six days of stagnation. 126 Moreover, the composition and content of microorganisms in household faucet water change greatly, even if stopped overnight. 138 Chen et al. 139 studied the effect of water stagnation on microbial pollution in a water purifier; the results showed that the growth of microorganisms in the water purifier was faster than in a DWDS, and the size of the microorganisms decreased with an increase in stagnation time. This suggests that microbial contamination caused by stagnation should be carefully considered in the design and usage guidance of building water supply systems (BWSSs) to ensure healthy drinking water.

Spatiotemporal effect

The spatiotemporal effect also changes the drinking water microbial community. 34,109,140,141 Bautista-de Los Santos et al. 142 observed significant changes in the bacterial community over a diurnal time scale and found that the degree and pattern of diurnal changes in the bacterial community in the DWDS were related to the presence/absence of low-content bacteria, and to changes in the relative abundance of dominant bacteria at each sampling site. Perrin et al. 143 found significant but moderate changes in bacterial community composition on large temporal and spatial scales in a drinking water distribution system in Paris. Potgieter et al. 94 found that α-proteobacteria and β-proteobacteria dominated the microbial community in drinking water after disinfection with different disinfectants. In addition, the richness, diversity, and evenness of the bacterial community were greater in winter than in summer. The spatial dynamics of the bacterial community exhibited distance attenuation. However, a survey on the microbial biogeography of drinking water in the Netherlands showed that the population exchange between the biofilm and the water matrix was limited; different DWDSs had different microbial communities, and the treated water had significant stability in time and space. 34

In addition, treated drinking water quality, including temperature, 132,144,145 suspended solids, 35,146 electrolytes, 28,125,147–149 disinfectants, 149 and organic matter 28 also influence microbial diversity in tap water. Sun et al. 28 reported that pH and COD were positively correlated with the relative abundance of Proteobacteria and Firmicutes . Ma et al. 148 reported that bacterial richness and diversity were positively related to SO 4 2− , Cl − , and HCO 3 − in the water supply, and negatively related to pH value. Chemical reactions other than microbial processes play a major role in the release of iron during the transition period of the water supply. Moreover, the role of residual chlorine in water quality cannot be underestimated. The disinfectant changes the bacterial community structure of the pipeline biofilm, and affects the water quality and the remodeling of the corrosion scale, further changing the kinetics of the corrosion process. 149

Prospects of microbial diversity analysis in drinking water biosafety

With the development of sequencing technology, in-depth characterization and evaluation has been conducted by researchers on microbial communities in DWDSs and BWSSs. Although microbiological safety assurance technology is relatively good, harmful bacteria such as pathogenic bacteria and ARB may still be detected in drinking water, posing a threat to public health. 150–154 It has been verified that every stage from the source to the tap has some influence on microbial diversity. Thus, researchers have conducted traceability analyses of microorganisms in tap water or estimated the impact on microbial conditions in drinking water based on existing water quality conditions to determine if emergency treatment methods are necessary. Marshall et al. 155 investigated the genotype similarities and geographic relationships of bacterial communities between humans and drinking water. The results indicated that drinking water may be a source of human Mycobacterium lentiflavum infection. Liu et al. 156 used the Bayesian “source tracing” method to determine the proportional contributions of source water, treatment water, and the distribution system in shaping the bacterial community in faucet water based on bacterial community fingerprints. The results showed that the source water had no obvious contribution to the bacterial communities of tap water and water in the distribution system. Loose sediments and biofilms show significant effects on phytoplankton and particle-related bacteria in faucet water, which are position dependent and subject to hydraulic changes. In addition, sequencing technology has been used to assess the safety of rural drinking water systems. The rich genetic footprint of pathogens in water samples from many reports suggests that the bacteria can be transmitted to humans. Thus, the importance of disinfection of raw water must be clearly communicated to rural communities to ensure the safe use of water. Studying the microbial community structure and its influence on drinking water is critical.

With the continuous improvement of sequencing technology in depth, accuracy, and economy, how and why the microbial diversity changes in the whole process of drinking water will be clearer. Future research may focus on the impact of new pollutants, traceability analysis and source control, as well as rapid detection and intelligent feedback.

This paper summarizes and clarifies the biological sequencing technologies applied in research on drinking water microbial communities, including the source drinking water quality, the treatment process, and the distribution system supply conditions, and indicates that all three steps can affect the tap water microbial community. A significant correlation was observed between the microbial populations in the source water and tap water, and the abundance of bacteria was largely affected by the treatment process and the distribution system condition. Thus, the microbiological safety assurance of drinking water must start from the source. The treatment process must be improved, the pipeline network route material must be carefully selected, and drinking water management should be strengthened from the factory to the client, to block the source (water protection), decrease the concentration (optimization of disinfection during DWTP), and control the flow (reduce growth in the DWDS). These mechanisms that need to be explored require the development of cheaper and more accurate biological sequencing technologies.

Author contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.

Conflicts of interest

There are no conflicts to declare.

Supplementary Material

Acknowledgments.

This work was supported by the National Natural Science Foundation of China (51979194). We also thank the research on water quality stability characteristics and countermeasures of the Fuzhou Water Supply System (Project No. 20203000) from Fuzhou Water Group Co. Ltd.

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Confronting the Nation's Water Problems: The Role of Research (2004)

Chapter: 3 water resources research priorities for the future, 3 water resources research priorities for the future.

The pressing nature of water resource problems was set forth in Chapter 1 . The solution to these problems is necessarily sought in research—inquiry into the basic natural and societal processes that govern the components of a given problem, combined with inquiry into possible methods for solving these problems. In many fields, descriptions of research priorities structure the ways in which researchers match their expertise and experience to both societal needs and the availability of research funding. Statements of research priorities also evolve as knowledge is developed, questions are answered, and new societal issues and pressures emerge. Thus, the formulation of research priorities has a profound effect on the conduct of research and the likelihood of finding solutions to problems.

Statements of research priorities developed by a group of scientists or managers with a common perspective within their field of expertise can have a relatively narrow scope. Indeed, this phenomenon has resulted in numerous independent sets of research priorities for various aspects of water resources. This has come about because water plays an important role in a strikingly large number of disciplines, ranging from ecology to engineering and economics—disciplines that otherwise have little contact with each other. Thus, priority lists from ecologists emphasize ecosystem integrity, priority lists from water treatment professionals emphasize the quantity and quality of the water supply, and priority lists from hydrologists emphasize water budgets and hydrologic processes. In recent years, the limitations of discipline-based perspectives have become clear, as researchers and managers alike have recognized that water problems relevant to society necessarily integrate across the physical, chemical, biological, and social sciences. Narrowly conceived research produces inadequate solutions to such problems;

these in turn provide little useful guidance for management because critical parts of the system have been ignored. For example, the traditional subdivision of water resource issues into those of quality and quantity is now seen as inadequate to structure future research, given that water quality and quantity are intimately, causally, and mechanistically connected. Similarly, theoretical studies of water flows (hydrology) and aquatic ecosystems (limnology) can no longer be viewed as independent subjects, as each materially affects the other in myriad ways. Finally, the physical, chemical, and biological aspects of water cannot adequately be investigated without reference to the human imprint on all facets of the earth’s surface. Thus, the challenge in identifying water resources research needs is to engage researchers in novel collaborations and novel ways of perceiving the research topics that they have traditionally investigated.

Water resources research priorities were recently extensively considered by the Water Science and Technology Board (WSTB) in Envisioning the Agenda for Water Resources Research in the Twenty-first Century (NRC, 2001a). This resulted in a detailed, comprehensive list of research needs, grouped into three categories ( Table 3-1 ); the reader is referred to NRC (2001a) for a detailed description of each research need. The category of water availability emphasizes the interrelated nature of water quantity and water quality problems and it recognizes the increasing pressures on water supply to provide for both human and ecosystem needs. The category of water use includes not only research questions about managing human consumptive and nonconsumptive use of water, but also about the use of water by aquatic ecosystems and endangered or threatened species. The third category, water institutions , emphasizes the need for research into the economic, social, and institutional forces that shape both the availability and use of water.

After review and reconsideration, the committee concluded that the priorities enumerated in the Envisioning report constitute the most comprehensive and current best statement of water resources research needs. Moreover, successful pursuit of that research agenda could provide answers to the central questions posed in Chapter 1 . However, the list of research topics is not ranked, either within the three general categories or as a complete set of 43. An absolute ranking would be difficult to achieve, as all are important parts of a national water resources research agenda. Furthermore, the list of research priorities can be expected to change over time, reflecting both changes in the generators of such lists and in the conditions to which they are responding. This chapter, thus, provides a mechanism for reviewing, updating, and prioritizing research areas in this and subsequent lists. It should be noted that the 43 research areas in Table 3-1 are of varying complexity and breadth. In addition, the committee expanded research area #21 (develop more efficient water use) from the version found in the Envisioning report to include all sectors rather than just the agricultural sector.

The increasing urgency of water-related issues has stimulated a number of scientific societies and governmental entities, in addition to the WSTB, to produce

TABLE 3-1 Water Resources Research Areas that Should Be Emphasized in the Next 10–15 Years

their own lists of research priorities. For example, the American Society of Limnology and Oceanography recently convened a workshop to draft a list of emerging research issues (ASLO, 2003). These issues included the biogeochemistry of aquatic ecosystems, the influence of hydrogeomorphic setting on aquatic systems, the impacts of global changes in climate and element cycles, and emerging measurement technologies. This list builds on the comprehensive analysis of research priorities for freshwater ecosystems set forth in The Freshwater Imperative ( Box 2-1 ; see also Naiman et al., 1995). Another list of research priorities was recently assembled by the European Commission (2003), Task Force Environment–Water, which emphasizes water availability and water quality and the social, economic, and political aspects of water management. Like the NRC (2001a) report, this research agenda sets forth broad areas of research, with more specific “action lines” within high-priority areas. However, the approach differs from NRC (2001a) in that water quality is separated from water availability, and the socioeconomic and political research agenda is oriented toward crisis management. The U.S. Global Change Program also identified interrelated issues of quantity, quality, and human society as key research needs (Gleick et al., 2000);

this research agenda emphasizes the development of models and methods of prediction as well as data collection and monitoring systems, and it emphasizes research on the socioeconomic and legal impacts of climate change.

This brief review of selected contemporary lists of research priorities, as well as the lists of research priorities shown in Box 2-1 , illustrates that the articulation and the ranking of research topics vary with the entity charged to develop a research agenda. It can be anticipated that future lists of priorities will also differ from these.

A METHOD FOR SETTING PRIORITIES OF A NATIONAL RESEARCH AGENDA

The business of setting priorities for water resources research needs to be more than a matter of summing up the priorities of the numerous federal agencies, professional associations, and federal committees. Indeed, there is no logical reason why such a list should add up to a nationally relevant set of priorities, as each agency has its own agenda limited by its particular mission, just as each disciplinary group and each committee does. There is a high probability that research priorities not specifically under the aegis of a particular agency or other organization will be significantly neglected. Indeed, the institutional issues that constitute one of the three major themes in Table 3-1 are not explicitly targeted in the mission of any federal agency. This is the current state of affairs in the absence of a more coordinated mechanism for setting a national water resources research agenda.

A more rigorous process for priority setting should be adopted—one that will allow the water resources research enterprise to remain flexible and adaptable to changing conditions and emerging problems. Such a mechanism is also essential to ensure that water resources research needs are considered from a national and long-term perspective. The components of such a priority-setting process are outlined below, in the form of six questions or criteria that can be used to assess individual research areas and thus to assemble a responsive and effective national research agenda. In order to ensure the required flexibility and national-scale perspective, the criteria should also be applied to individual research areas during periodic reviews of the research enterprise.

Is there a federal role in this research area? This question is important for evaluating the “public good” nature of the water resources research area. A federal role is appropriate in those research areas where the benefits of such research are widely dispersed and do not accrue only to those who fund the research. Furthermore, it is important to consider whether the research area is being or even can be addressed by institutions other than the federal government.

What is the expected value of this research? This question addresses the importance attached to successful results, either in terms of direct problem solving or advancement of fundamental knowledge of water resources.

To what extent is the research of national significance? National significance is greatest for research areas (1) that address issues of large-scale concern (for example, because they encompass a region larger than an individual state), (2) that are driven by federal legislation or mandates, and (3) whose benefits accrue to a broad swath of the public (for example, because they address a problem that is common across the nation). Note that while there is overlap between the first and third criteria, research may have public good properties while not being of national significance, and vice versa.

Does the research fill a gap in knowledge? If the research area fills a knowledge gap, it should clearly be of higher priority than research that is duplicative of other efforts. Furthermore, there are several common underlying themes that, given the expected future complexity of water resources research, should be used to evaluate research areas:

the interdisciplinary nature of the research

the need for a broad systems context in phrasing research questions and pursuing answers

the incorporation of uncertainty concepts and measurements into all aspects of research

how well the research addresses the role of adaptation in human and ecological response to changing water resources

These themes, and their importance in combating emerging water resources problems, are described in detail in this chapter.

How well is this research area progressing? The adequacy of efforts in a given research area can be evaluated with respect to the following:

current funding levels and funding trends over time

whether the research area is part of the agenda of one or more federal agencies

whether prior investments in this type of research have produced results (i.e., the level of success of this type of research in the past and why new efforts are warranted)

These questions are addressed with respect to the current water resources research portfolio in Chapter 4 .

How does the research area complement the overall water resources research portfolio? The portfolio approach is built on the premise that a diverse mix of holdings is the least risky way to maximize return on investments. When applied to federal research and development, the portfolio concept is invoked to mean a mix between applied research and fundamental research (Eiseman et al., 2002). Indeed, the priority-setting process should be as much dedicated to ensuring an appropriate balance and mix of research efforts as it is to listing specific research topics. In the context of water resources, a diversified portfolio would capture the following desirable elements of a national research agenda:

multiple national objectives related to increasing water availability, improving water quality and ecological functions, and strengthening institutional and management practices

short-, intermediate-, and long-term research goals supporting national objectives

agency-based, contract, and investigator-driven research

both national and region-specific problems being encompassed

data collection needs to support all of the above

Thus, the water resources research agenda should be balanced in terms of the time scale of the effort (short-term vs. long-term), the source of the problem statements (investigator-driven vs. problem-driven), the goal of the research (fundamental vs. applied), and the investigators conducting the work (internally vs. externally conducted). An individual research area should be evaluated for its ability to complement existing research priorities with respect to these characteristics. Definitions of these terms are provided in Box 3-1 , and the appropriate balance among these categories is addressed in Chapters 4 and 6 .

Furthermore, it is important to consider whether the research fills gaps in the desired mix of water availability, water use, and institutional topics (as demarcated in Table 3-1 ). A final level of evaluation would consider how well the research responds to the four themes described in this chapter (interdisciplinarity, broad systems context, evaluation of uncertainty, and adaptation).

To summarize, a balanced water resources research agenda will include items of national significance for which a federal role is necessary; fill knowledge gaps in all three topical areas (water availability, water use, and institutions); incorporate a mixture of short-term and long-term research, basic and applied investigations, investigator-initiated and mission-driven research, and internal and external efforts; and build upon existing funding and research success. As noted above, some of these issues are addressed in subsequent chapters, with respect to the current water resources research agenda (see Table 3-1 ). The remainder of this chapter expands upon the four overarching themes that should form the context within which water resources research is conceptualized and performed.

THEMES OF FUTURE WATER RESOURCES RESEARCH

There are several common underlying themes that should be used to (1) integrate and reconcile the numerous lists of research priorities currently being generated by agencies and scientific societies and (2) provide some overall direction to the multiple agencies and academic entities that carry out water resources research. These themes are interdisciplinarity, a broad systems context, uncertainty, and adaptation in human and ecological response to changing water resources.

The term interdisciplinarity refers to the fact that no question about water resources can be now adequately addressed within the confines of traditional disciplines. The research community recognizes that the physical, chemical, and biological/ecological characteristics of water resources are causally and mechanistically interrelated, and all are profoundly affected by the human presence in the environment. Therefore, it is necessary to understand water resources with reference to a range of natural and social scientific disciplines.

The phrase broad system context refers to the perception that all properties of water are part of a complex network of interacting factors, in which the processes that connect the factors are as important as the factors themselves. Both interdisciplinarity and broad systems context place water resources within the emerging field of complex systems (Holland, 1995; Holland and Grayston, 1998).

Uncertainty —the degree of confidence in the results and conclusions of research—has always been an important component of scientific research. All measurements and observations entail some degree of error, as do methods of data analysis, estimation, and modeling. Understanding the sources and amounts of uncertainty attached to estimates of flow, water quality, and other water resource variables is crucial, because so many practical and often expensive decisions hinge on the results. In short, understanding and measuring uncertainty are central to making informed decisions about water resources. Furthermore, an emphasis on uncertainty also implies attention to the extent and quality of the data available for generating estimates of important variables; this attention in turn implies a need to improve technologies for research and monitoring. Finally, an understanding of the uncertainties in data, models, and scientific knowledge lies at the heart of risk analysis and the development of policies and strategies to handle complex environmental problems (Handmer et al., 2001).

Finally, adaptation is a key component of the human, as well as ecological, response to the ever-changing environment. Human society has always changed in response to changing resources; the challenge is now to anticipate environmental changes and develop adaptive responses before catastrophe or conflict force such evolution. This is particularly pressing as research ascertains the impact of human activities on ecosystems, such as greenhouse gas release into the atmosphere and deforestation. Adaptation may involve modifying social mores and norms or forming new government policies including economic policies. For

example, there is little doubt among many researchers that emerging water scarcity will demand greatly altered expectations and behaviors in society. It may also involve new methods of managing resources in which flexibility to respond to unanticipated or rapidly occurring problems is the guiding principle.

These four themes are illustrated below, using a subset of the research priorities developed in Table 3-1 . The portfolio of existing water resources research tends not to be organized along these thematic lines.

INTERDISCIPLINARY NATURE OF RESEARCH

The need for expertise from many disciplines to solve individual water resource problems is widely recognized and has produced repeated calls for collaborative, interdisciplinary approaches to research (Cullen et al., 1999; Naiman and Turner, 2000; Jackson et al., 2001). For example, aquatic ecosystems research now emphasizes the tight linkages between the traditional biological and ecological issues and both hydrology and human use of water (Poff et al., 1997; Richter et al., 1997). Similarly, the transformations of nutrients and pollutants reflect the interplay of hydrology and microbial ecology (Brunke and Gonser, 1997). Examples of several research areas from Table 3-1 are given below to elaborate on the interdisciplinary nature of water resources research.

outline of contaminant fate and transport makes it clear that this research priority necessitates a collaborative effort by physical chemists, soil scientists, hydrologists, geologists, microbiologists, plant scientists, and ecologists.

Similarly, wetlands are structured by water regimes in which very small variations in flow timing and amounts, in seasonal patterns of flow variation, in flow extremes, and in the duration of wet and dry events have very large effects on the biota (Mitsch and Gosselink, 2000; NRC, 2001b). Withdrawals of both groundwater and surface waters for human use can alter the flow regime, such that even subtle alterations can have large effects on the biota and function of the downgradient wetlands. Current controversy about the failure of mitigation methods and policy to meet the goal of “no net loss” of wetlands (Turner et al., 2001) is rooted in the difficulty of reproducing wetland hydrology in created and restored wetlands (NRC, 1995, 2001b). At the same time, the institutions and policies that are used to implement the goal of “no net loss” are being questioned and challenged. Wetland restoration thus demands research that integrates hydrology, plant and animal ecology, and social science.

approach is urgently needed. There are numerous factors that can confound the successful operation of irrigation projects on a sustainable basis. Problems related to climate variability, soil salinity, deterioration of the irrigation infrastructure, and social instability contributed to the collapse of the ancient empires, like the Akkadians and Sassanians who lived in the Tigris and Euphrates River valley, or the Hohokams who prospered for a millennium along the Gila and Salt rivers of now south-central Arizona (Postel, 1999). Today’s challenges are expected to be similar, because irrigation agriculture is associated with arid and semiarid environments where climate variability significantly impedes the successful long-term operation of these systems. In modern times, storage provided by large dams has reduced the impact of short-term fluctuations in climate. However, the looming prospect of global climate change, coupled with water demands of growing populations, has tremendous implications for irrigated agriculture in the next century (NAST, 2000).

The research challenges are to provide better projections of how climate might change and to improve hydrologic observation systems to document these changes (NAST, 2000). In addition, because large-scale structural solutions for water supply for irrigated agriculture are difficult to justify on social and economic grounds (Pulwarty, 2003), social science research on determinants of water use in the agricultural sector and agronomic research on improved crop varieties for dryland agriculture are needed. The problem of sustaining irrigated agriculture becomes even more interdisciplinary when one considers the need to understand the response of soils and surface water systems (in terms of chemistry and ecology) to alterations in irrigation return flows and the need to understand how economics might produce flexible strategies for irrigation. Assessments like those relating to the restoration of the Colorado River delta (Luecke et al., 1999) or the San Francisco Bay delta (McClurg, 1997) make clear the inherent multidisciplinarity of developing water supply systems for irrigated agriculture within an environment of competing demands and constraints.

Efforts are underway to reduce the nonpoint source contamination of the nation’s waters (e.g., Mississippi River Task Force, 2001). However, the enormous scope and scale of the problem are daunting, as land-use practices in several sectors of the economy often result in degradation of water resources in areas far downstream from the site(s) of impact. For example, excessive loading of nitrogen derived mainly from agriculture in the Midwest has contributed to an oxygen-

depleted zone in the Gulf of Mexico that can be as large as the state of New Jersey (Goolsby and Battaglin, 2000). Solving this problem requires not only resolving multiple scientific questions, but also resolving social, economic, and political complexities at scales ranging from the local to the national. Combating nonpoint source pollution will require both basic and applied research. For example, although good progress is being made in elucidating factors controlling contaminant loading (e.g., Alexander et al., 2000; Dubrovsky et al., 1998; Porter et al., 2001), more work is required to understand the fate and transport of nonpoint source pollutants and their fundamental effects on human and environmental health, particularly for pesticides and their transformation products (USGS, 1999). This understanding will require decades of high-resolution chemical and biological monitoring coupled with new analytical and modeling approaches.

The key physical approaches for controlling nonpoint source contamination are local mitigation strategies provided by wetlands, sedimentation ponds, and riparian areas along streams, and land-management strategies that reduce runoff and chemical use. Mitigation is an expensive option, both in terms of implementation and reductions in farmed area. Considerable research will be needed in proof-of-concept, design, and in cost/benefit analyses, requiring the participation of ecologists, soil scientists, hydrologists, and geologists to determine the appropriate size, type, and placement of structures. Changes to farming practices on a continental scale will require equally complex research by agronomists, soil scientists, hydrologists, economists, and social scientists because broad stakeholder education and involvement, voluntary actions, new legislative authority, and coordination across localities and regions will be necessary to implement such changes (Mississippi River Task Force, 2001). Finally, contaminant fluxes from land to streams and rivers may well undergo chronic increases as a result of larger rainfall events associated with future climate change. Thus, progress in controlling nonpoint contamination will require interdisciplinary research linking the historically important areas of agriculture, hydrology, and biology with emerging areas of climate change, natural resource economics, education, and human dimensions of decision making.

BROAD SYSTEMS CONTEXT

The systems approach mandates that a problem be addressed by specifying the entities that contribute to the problem, the linkages among these entities, the logical or physical boundaries to the system, and the inputs and outputs to the system as a whole (in other words, linkages to entities deemed to be outside the system). The idea has its roots in physics, in which a “system” is a thermodynamic concept related to the flow and conservation of energy. The linkages among entities within a system are as important as the entities themselves; thus, a system is more than the sum of its parts (see Box 3-2 ). Systems usually show nonlinear dynamics, and the nonlinearities among sets of linked entities often lead to

unanticipated and complex behavior, and also to surprises—events that cannot be exactly predicted, or that are outside the realm of prior experience. Indeed, these characteristics of system behavior have been highlighted as key aspects of environmental problems (NRC, 1997a). Thus, considering water resources research within a broad systems context implies elucidating interrelationships among entities that, at first glance, might not be thought to be related. This approach also mandates that small-scale problems be viewed within a larger-scale perspective, which may profoundly alter the understanding of causal and quantitative relationships.

The need to view some of the research priorities set forth in Table 3-1 within a broad systems context is illustrated below.

As an example, the Idaho Department of Water Resources increasingly must resolve conflicts among citizens concerning competing demands for (and assertion of rights over) surface water and groundwater, and it also must resolve interstate water conflicts between Idaho and neighboring states (Dreher, 2003). Provision of adequate water for the habitats of endangered and threatened aquatic species is also part of the state’s responsibilities. Idaho contains six aquifers that span interstate lines and that affect surface water flows in adjoining states. Currently, management of both groundwater and surface water supplies is being undertaken without adequate knowledge of the connections between the two sources, leading to conflicts and shortages. The lack of a comprehensive understanding of the entire regional hydrogeologic system and its links to both human use and natural ecosystems is leading to increased litigation, with current needs not being met. In order to help resolve these conflicts, management agencies need

accurate measurements of water flows and water stocks over a range of temporal and spatial scales. Moreover, the influences of natural processes, natural climate variability, and human intervention in the water system must be monitored.

transpiration rates from vegetation and evaporation rates from the soil surface, thus altering soil and atmospheric moisture content and the likelihood of rain and forest fire. These in turn will have large effects on regional hydrology. These connections, which have been well documented for tropical rain forests, are germane to understanding the connections between hydrology and climate worldwide.

Moreover, the driving force for global climate change—the rise in greenhouse gas concentrations associated with human activities—will also affect aquatic ecosystems in ways that may amplify or dampen the effects of hydrologic change alone. For example, higher CO 2 concentrations will alter leaf chemistry and the relative growth rates of different plant species. Both changes may affect the palatability of litter to decomposer and consumer organisms, in turn affecting decomposition rates, nutrient cycling rates, and ultimately the density and species

composition of the plant community. Changing CO 2 concentrations may also affect pH of the water, with cascading effects on the biota, although changes in flow regime may interact with increased dissolution of CO 2 to modify this effect. These feedbacks are being incorporated into the models that are used to predict the effects of greenhouse gas emissions on climate and water resources. Unfortunately, the great complexity of the system results in model predictions that span a range of values too large and uncertain to be usable for regional or local water resource management at this time (Chase et al., 2003).

Just as energy supply interacts with water use in multiple ways, as described above, energy extraction (for example, oil and gas development in the West) similarly affects water use in complex ways. Impacts of energy extraction on biotic resources may affect water supply and water use indirectly, by limiting potential options to manage water resources. For example, recent and rapid development of methane gas resources in the Powder River Basin is causing major disruptions in groundwater supply sources (BLM, 2003). Depending on the method of energy extraction, water quality is often impaired. Drilling muds, for example, frequently contain additives that have the potential to contaminate downstream or downgradient water supplies (EPA, 2000).

UNCERTAINTY

Water resource management relies on monitoring data, scientific understanding of processes in the water cycle and the ecology of aquatic ecosystems, and ultimately predictive models that can forecast hydrologic conditions and biotic and human responses. All of these types of information are subject to uncertainty. Uncertainty results from many sources, including measurement systems that are not sufficiently precise or that do not generate sufficient quantities of high-quality data, instrument failures, human errors in designing and implementing studies, and simply a lack of understanding of the processes and phenomena under investigation. Uncertainty affects both the analysis of data and the construction of models to make water resource predictions. Although inherent to research, uncertainty can be managed by explicit recognition of its occurrence coupled with quantitative methods of measuring its importance and incorporating it into decision making. By describing the degree of uncertainty in research results (and by inference the reliability of the measurements and models), researchers can adjust the expectations for the use of their data and models accordingly. Reliable estimates of uncertainty contribute directly to successful risk management and the development of environmental policy (Funtowicz and Ravetz, 1990; Dovers et al., 2001). It should be noted that the above definition of uncertainty is broader than that espoused by some federal agencies (e.g., the U.S. Army Corps of Engineers, for which uncertainty refers to situations in which the probability of potential outcomes and their results cannot be described by objectively known probability distributions). Below are examples illustrating the importance of the quantification of uncertainty for some of the research priorities listed in Table 3-1 .

To predict the fate and transport of contaminants from the proposed repository, the DOE has developed a complex mathematical model called Total System Performance Assessment (TSPA) that itself depends on the output of dozens of process-oriented models. The success of the DOE’s license application depends in large measure on the confidence placed in the TSPA predictions of contaminant transport and the technical basis for those predictions. Conceptual and model uncertainty and the explicit quantification of this uncertainty are central to the question of technical basis. As noted by the U.S. Nuclear Waste Technical Review Board in a letter to Congress (NWTRB, 2002): “Resolving all uncertainty is neither necessary nor possible. However, uncertainties about the performance of those components of the repository system relied upon to isolate waste are very important, and information on the extent of uncertainty and assumed conservatism associated with the performance of these components may be important to policy makers, the technical community, and the public.” Regardless of policymakers’ and the public’s varying levels of tolerance for uncertainty, it can still be said that results of research to quantify, and perhaps further reduce, uncertainties can contribute to the quality and credibility of impending public policy decisions.

remediate polluted waterbodies. Mandated by the Clean Water Act, a TMDL is a calculation of the maximum pollutant loading that a waterbody can sustain and still meet its water quality standards. If the current loadings are higher, then the TMDL must be accompanied by a remedial plan on how to reduce the loadings via best management practices (BMPs). TMDLs are established for an impaired waterbody by using a combination of fate and transport models for the target pollutant or stressor and available waterbody data. This requires both watershed models (which take into account such processes as the movement of pollutants across land) and water quality models (which incorporate in-lake pollutant transport and transformation). Models are also potentially needed to predict the effectiveness of certain BMPs. Many of the watershed and water quality models in use suffer from inadequate representation of physicochemical processes, inappropriate applicability, and lack of training of model users (EPA, 2002). Similarly, the data on which TMDLs are based may be inconsistent in quality or inappropriate in terms of the frequency and extent of sampling. Finally, the methods used to identify impaired waterbodies are often inadequate because of deficiencies in state monitoring networks. All of these problems generate uncertainties in the applicability and effectiveness of the resulting TMDL. The development of improved methods of quantifying uncertainty in both the models and the listing criteria, especially in setting “margin of safety” criteria, is critical if informed decisions about restoring polluted waterbodies are to be made. Indeed, the central role of uncertainty has been a major conclusion of several recent studies critically examining the TMDL program (NRC, 2001c; Borsuk et al., 2002; EPA, 2002).

Water resource managers are subject to increasingly diverse, often conflicting forces. For example, it was relatively simple to develop the knowledge base needed to provide predictable amounts of water to agriculture when this was the only use for a water supply. It becomes much more complicated when agricultural uses need to be met while new demands come from urbanizing areas and from governmental and nongovernmental entities demanding water for endangered species or aquatic ecosystem support, such that the total demand exceeds the readily available supply. In such contexts, adaptability becomes essential. Managers, users, and advocates need to have the flexibility to imagine and adopt novel solutions to water resource problems, and researchers in their search for solutions need to have the flexibility to adapt their research to problems that may have been unimaginable in the recent past. Furthermore, the complexity of current problems may demand that combinations of solutions be applied creatively to different components of a problem. This emphasis on adaptability of both the research community and the managers and users of water needs to be an organizing concept for water resources research. Thus, “adaptation” is defined as a combination of flexibility in solving problems and, more fundamentally, a shift in

norms and standards that can result from confronting novel situations. A related concept in water resources is that of adaptive management, a learning-while-doing process in which a management action is viewed as an experiment, and as managers learn from their successes and failures, they adjust their management actions accordingly (Holling, 1978; Geldof, 1995; Haney and Power, 1996; Wieringa and Morton, 1996; Lee, 1999; NRC, 1999, 2003b, 2004b).

Below are examples of how adaptation is a key element in addressing some of the research priorities listed in Table 3-1 .

This combination of challenges will require adaptability on the part of both researchers and users. For example, creative water delivery systems, such as inhome gray water recycling or dual-home distribution systems (Wilchfort and Lund, 1997) that bring potable water to a few taps and slightly less pure water to other taps for cleaning purposes or industrial needs, will require research. This includes research to develop the technologies to implement such systems and research to understand how people adapt to new modes of obtaining and using water (see Box 3-3 ) and how such a transition might be effected. Individuals’ views of water-related risks (Loewenstein et al., 2001), in-home uses of water, and the value of water resources (Aini et al., 2001) will also need to adapt in order for these technological changes to be successful in maintaining drinking water quality.

diverse biological community within aquatic and riparian ecosystems. However, human actions to minimize floods and droughts and to provide reliable water for consumption at constant rates can eliminate this natural variability (Dynesius and Nilsson, 1994). In order to balance these effects, management of the water, the ecosystem, and the affected social groups must be adaptive in several respects.

For example, ecological restoration, while guided by ideals of the undisturbed or historical state of the ecosystem, increasingly must accept the lesser but still critical goal of repairing damaged systems to a partially restored state. This will be necessary because of insufficient knowledge of the undisturbed state, permanent alteration of the landscape through built structures and intensive land use, and the prevalence of nearly ineradicable nonnative species. An example is provided by the Laurentian Great Lakes, where overfishing and the onslaught of the sea lamprey brought about the decline of native fishes, including the lake trout. At the same time, exotic species of smaller “forage” fish proliferated, resulting in the famous die-off of alewives that littered Chicago’s beaches in the early 1970s. Fisheries managers attempted a bold experiment, importing coho and king salmon from the Pacific Northwest, a highly successful adaptation to a “collapsing” ecosystem. Now with well over one hundred nonnative species, the Great Lakes pose a continuing challenge to ecologists and fisheries managers seeking to manage and restore the ecosystem.

Adaptation is anticipated to be particularly difficult but absolutely essential in large aquatic ecosystems where there are multiple competing interests (fisheries scientists, communities relying on fishing, farmers, water resource and dam managers, etc.) (Peterson, 2000). The scale of conflicts arising from the plexus of interests involved in large-scale ecosystem restoration is illustrated by the recent Klamath (NRC, 2003a) and Columbia River controversies (Gregory et al., 2002; NRC, 1996, 2004a). Clearly, research is needed to develop adaptive approaches to both managing the resources (water, fish, etc.) as well as the various human populations involved in these issues. Flexibility, an understanding that a variety of alternative strategies are possible, and a willingness to adjust previously assumed “rights” will be essential in finding compromises between competing human and ecosystem demands. In addition, the use of adaptive management procedures will be necessary.

that people know what is expected or required and can act in accordance. Thus, for example, investments can be made with the expectation that changes in law will not undo the hoped-for return that motivated the investment. Actions can be taken without fear that a change in the rules will punish the actor. A stable legal system is important economically and socially.

However, this societal interest in stability may conflict with other emerging societal interests in periods of active change. During the 1970s, for example, Congress imposed far-reaching new legal requirements on those whose activities generated certain types of pollution from readily identifiable (point) sources, forcing massive investment in technologically advanced systems for the treatment of particular pollutants prior to their discharge into the environment. The years immediately following enactment of these laws were ones of considerable turmoil and conflict as uncertainties respecting their implementation were disputed and resolved. With these requirements now firmly embedded into the plans and actions of the regulated community, stability has returned. So too has resistance to any significant change in approach, even if such change might better accomplish the objectives of these laws.

Laws governing human uses of water have traditionally been concerned with determining who may make use of the resource and under what conditions. In those states east of the 100th meridian, owners of land adjacent to waterbodies essentially share the ability to use the water (riparian doctrine). Uses must be “reasonable,” with reasonable use generally being measured by the harm that might be caused to other riparian users. In the western states, uses are established through a process of appropriation of water—that is, establishing physical control—and then applying the water to a “beneficial use.” It is a priority system, protecting full use of available water by those first to appropriate it.

The appropriation system arose in the context of water-scarce settings. Direct use of water from streams initially for mining and then for agriculture was essential, and it required the investment of time and money to build the structures that would make that use possible. Users wanted certainty about their rights of use versus other subsequent users, and the prior appropriation system provided that certainty. The appropriation system does not, however, readily accommodate changing uses of water or integrate new uses. Nor does it incorporate the use of water for serving physical and ecological functions within the hydrologic cycle. This suggests that water laws need to be more adaptable if they are to meet changing societal needs. As a first effort, many western states have adopted water transfer laws to accommodate changing water uses, including environmental needs such as instream flows. These states have successfully combined the certainty of the prior appropriation system with the ability to meet emerging demands.

The process of restoring a sustainable level of physical and ecological integrity to our hydrologic systems must work within long-established legal and institutional structures whose purpose has been to promote and support direct human uses. The challenge is to develop societally acceptable approaches that allow

those uses to continue but in a manner that is compatible with ecosystem functionality.

LIMITATIONS TO THE CURRENT WATER RESOURCES RESEARCH ENTERPRISE

The articulation of these four themes—interdisciplinarity, broad systems context, uncertainty, and adaptation—is intended to reorient the disparate research agendas of individual agencies as well as individual researchers. The hope is that an emphasis on these overarching themes will lower barriers to research on newly emerging water resources problems. Research agendas of the federal agencies are driven by their specific mandates, such as the agricultural impacts on water (U.S. Department of Agriculture), water as a component of climate (National Oceanic and Atmospheric Administration), or reservoir management (U.S. Bureau of Reclamation). Often there is a need for agencies to center their missions around clearly articulated, politically prominent issues in order to secure funding. These tendencies promote more narrowly focused research and present barriers to addressing difficult, large-scale problems. Furthermore, agencies are locked into policies devolving from their legislative and administrative history, and they cannot create new policies that cut across administrative or management units; thus, research is constrained by policies that easily become antiquated or irrelevant (Stakhiv, 2003). Finally, water resource problems are frequently conceived to match short-term funding cycles (Parks, 2003), resulting in inadequate knowledge for effective water management.

Similarly, individual scientists frame research in terms of their disciplinary training and work environment, which creates barriers to the kind of research needed to solve the complex problems that are now prominent. Indeed, the reluctance of scientists to reach outside their disciplines has been identified elsewhere as a barrier to effective water resources research (Parks, 2003). Institutional and professional constraints on priority setting also mitigate against effective research because they inhibit creative, innovative, and rapid responses to newly emerging or unanticipated problems.

Water resource problems are commonly assumed to be only local or regional in scope because water management entities and water supply systems operate on these scales. However, some water-related problems have become truly national in scope, either because of their very large spatial scale (e.g., the connection of the upper Mississippi drainage basin with hypoxia in the Gulf of Mexico) or because controversies rage over the same water issues in many states throughout the nation. Unfortunately, the current organization of water resources research promotes site- and problem-specific research, which results in narrowly conceived solutions that are often not applicable to large-scale, complex problems or to similar issues in other regions of the country (Stakhiv, 2003). Federal agencies may see only the local character of a problem, without understanding the some-

times subtle ways in which local problems are widely replicated around the country, and may conclude that such problems are not appropriately addressed with federal resources. State representatives advised the committee that they rarely have the financial or scientific resources to address problems that have local manifestations but national significance. Thus, such research can fail to be carried out because of limitations at both the federal and state levels.

Finally, the ability to carry out research on water resources may be limited by the availability of adequate long-term data (as discussed in Chapter 5 ). Hydrologic processes are characterized by the frequency with which events of a given magnitude and duration occur. Infrequent but large-magnitude events (floods, droughts) have very large economic, social, and ecological impact. Without an adequately long record of monitoring data, it is difficult, if not impossible, to understand, model, and predict such events and their effects.

By emphasizing interdisciplinarity, broad systems context, uncertainty, and adaptation as overarching research guidelines, the specific research agendas of agencies and, hopefully, individual scientists can be made more relevant to emerging problems. A framework of research priorities based on these overarching themes is more likely to promote flexible, adaptive, and timely responses to novel or unexpected problems than research programs constrained by priority lists developed solely with respect to agency missions. The complexity and urgency of water resource problems demand a framework that widens the scope of inquiry of researchers and research managers and forces them to conduct research in novel ways.

CONCLUSIONS AND RECOMMENDATIONS

Although the list of topics in Table 3-1 is our current recommendation concerning the highest priority water resources research areas, this list is expected to change as circumstances and knowledge evolve. Water resource issues change continuously, as new knowledge reveals unforeseen problems, as changes in society generate novel problems, and as changing perceptions by the public reveal issues that were previously unimportant. Periodic reviews and updates to the priority list are needed to ensure that it remains not only current but proactive in directing research toward emerging problems.

An urgent priority for water resources research is the development of a process for regularly reviewing and revising the entire portfolio of research being conducted. Six criteria are recommended for assessing both the scope of the entire water resources research enterprise and also the nature, urgency, and purview of individual research areas. These criteria should ensure that the vast scope of water resources research carried out by the numerous federal and state agencies, nongovernmental organizations, and academic institutions remains focused and effective.

The research agenda should be balanced with respect to time scale, focus, source of problem statement, and source of expertise. Water resources research ranges from long-term and theoretical studies of basic physical, chemical, and biological processes to studies intended to provide rapid solutions to immediate problems. The water resources research enterprise is best served by developing a mechanism for ensuring that there is an appropriate balance among the different types of research, so that both the problems of today and those that will emerge over the next 10–15 years can be effectively addressed.

The context within which research is designed should explicitly reflect the four themes of interdisciplinarity, broad systems context, uncertainty, and adaptation. The current water resources research enterprise is limited by the agency missions, the often narrow disciplinary perspective of scientists, and the lack of a national perspective on perceived local but widely occurring problems. Research patterned after the four themes articulated above could break down these barriers and promise a more fruitful approach to solving the nation’s water resource problems.

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In order to confront the increasingly severe water problems faced by all parts of the country, the United States needs to make a new commitment to research on water resources. A new mechanism is needed to coordinate water research currently fragmented among nearly 20 federal agencies. Given the competition for water among farmers, communities, aquatic ecosystems and other users—as well as emerging challenges such as climate change and the threat of waterborne diseases— Confronting the Nation's Water Problems concludes that an additional $70 million in federal funding should go annually to water research. Funding should go specifically to the areas of water demand and use, water supply augmentation, and other institutional research topics. The book notes that overall federal funding for water research has been stagnant in real terms for the past 30 years and that the portion dedicated to research on water use and social science topics has declined considerably.

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• Climate Change and Accessibility to Safe Water The paper discusses climate change’s effect on water accessibility, providing graphs on water scarcity and freshwater use and resources.
• Effects of Climate Variability on Water Resources, Food Security, and Human Health Evaluating the effects of climate variability on water, food, and health will help identify the areas for improvement and offer solutions to current environmental challenges.
• Water Accessibility and Quality The following case study explores the effect of negligence towards water stewardship and provides recommendations on the roles of stakeholders in the process.
• Water Pollution Causes, Effects and Solutions This essay seeks to examine the concept of water pollution, its causes, effects and solutions to water pollution. Water pollution takes place in various water bodies all over the world.
• Bottled Water Impact on Environment This paper seeks to amplify the need for regulation of the used water bottles. It is quite obvious that water bottles are the highest in a number of all bottles thrown away after use.
• How Access to Clean Water Influences the Problem of Poverty Since people in some developing countries have insufficient water supply even now, they suffer from starvation, lack of hygiene, and water-associated diseases.
• Fresh Water Toxins: Serious Threat to Health This paper discusses fresh water toxins as a serious threat to health, analyzes Los Angeles drinking water, access to clean water and sanitation.
• Fiji Water Case Study Analysis Brandon Miller aims to establish a business that is the distribution of Fiji water for Monroe and Wayne market areas.
• Water Management in Sustainable Engineering The current essay demonstrates the significance of sustainable engineering on the example of wastewater treatment and consequent water reuse.
• Lake Mattoon: Recreational Site and Water Reservoir Lake Mattoon remains one of Coles county’s best recreation sites and major water reservoirs; it is a big, man-made lake with lush green shores and big fish populations.
• Is Bottled Water Safe for Public Health? Bottled water is just water but is marketed in such a way that makes it appear as healthy because it is positioned as “bottles water is healthy”.
• Pressurized Water Reactors: An Analysis The paper describes the operations of a Pressurised Water Reactors (PWR) plant in-depth, discusses the functions of PWR plants, their advantages and disadvantages.
• Glacéau Company: Vitamin Water Ethics The business practice of this paper is the production and sale of vitamin water by Glacéau in which the company states that the water being sold has been “enriched” with vitamins.
• Addressing the Urgent Challenge of Water Pollution The essay addresses the pressing issue of water pollution, highlighting its widespread impact on communities and the environment.
• Resolutions to Fight Water Scarcity The World Health Organization outlines water scarcity as a global crisis affecting more than 2.8 billion people.
• Studying the Venturi Effect Through Water Flow Calculation The Venturi effect is of particular importance in fluid dynamics, characterizing the pressure drop of a fluid as it flows through narrow spaces.
• Assessment: Dubai Electricity and Water Authority As a key component of Dubai’s economy, DEWA is critical in assisting the Emirate’s growth and transition to a zero-economy economy.
• Water Scarcity as Effect of Climate Change Climate change is the cause of variability in the water cycle, which also reduces the predictability of water availability, demand, and quality, aggravating water scarcity.
• Land Usage and Water Quality in Saudi Arabia The effect of land use in Saudi Arabian water quality has intensified the region’s water crisis, causing economic, ecological, and social challenges.
• Essentials of Water in Supporting Biological Systems Water is essential in supporting the biological system in various ways; the properties of water help in understanding its importance.
• Combating Arsenic Contamination in Water The well known fact is that water is the most valuable natural resource that exists and without which survival of life is impossible.
• Baxter Water Treatment Plants and Public Health The Baxter Water Treatment Plant is the largest water treatment facility in Philadelphia, supplying about 60 percent of the city’s drinking water.
• Benefits of Water Birth Overview Waterbirth remains to be a controversial approach. The studies examined in this paper provide some evidence for the benefits that waterbirth has.
• First Nations Communities Water Resources Drinking water is by no means an infinite resource, but there are places in the world where women and children spend hours each day just to collect it.
• The Global Water Crisis: Issues and Solutions The water crisis has now been associated with the reduction in food quantity besides the scarcity of safe drinking water.
• Water Scarcity in the Middle East The Arab region has always had issues with the water supply but as the population continues to grow steadily, this issue has become even more alarming
• Activation Energy for Viscous Flow of Water, Acetone, Toluene, and o-Xylene The aim of the research was to investigate the hypothesis that the activation energy of a substance depends on intermolecular forces that arise in this substance.
• Water Treatments and Maximum Plant Height The first research question was how different water treatments affect maximum plant height. The experiment involved 12 plants – 6 plants for each type of water.
• Water Resources in Australia: Usage and Management Australia is one of the driest continents in the world. Various governmental and non-governmental institutions have teamed up to face the challenges facing people as far as water is concerned.
• Water Management in the “Flow” Documentary The documentary “Flow” discusses and describes two significant things that are preventing people from having access to freshwater.
• Water Quality Improvement for Global Health This proposal determines the necessity of water quality from the perspective of global health. The funding will be provided by the government and non-governmental organizations.
• “Erin Brockovich” Film and 2014 Flint Water Crisis This paper analyzes the movie “Erin Brockovich” and compares it with the current situation in Flint, which started in April 2014.
• Environmental Legislation: Clean Water Act Clean Water Act determines water quality standards, serves as a basis for the enactment of pollution control programs, and regulates the presence of contaminants in surface water.
• Bottled Water Impacts on Environment As the use of bottled water continue to rise steadily around the world, many critics have focused on its impacts on the environment, economy and other social implications related to the use.
• Water in the Atmosphere The relative humidity of air can be changed by changing either the temperature of the thermodynamic system in question or the pressure in the system under consideration.
• Water Management and Ecology Issues The paper studies water management, its various implications and explains why this area is important on examples of environmental issues.
• Water Crisis in Nigeria: Project Management As Africa’s most populous and largest economy, Nigeria faces various water-related challenges, from water scarcity in the north to water pollution in the south.
• Harmonie Water: Bottled Water Production in the U.S. The global market for bottled water is a highly competitive supply environment. The frequent introduction of several firms into the market is the primary cause of this.
• Human Energy Consumption and Water Power Human energy use is significantly low compared to natural energy flow. Waterpower is not significant in energy flow because it is renewable energy.
• Agriculture, Water, and Food Security in Tanzania This paper evaluates the strategies applicable to the development and further maintenance of agriculture, water, and food security in Tanzania.
• Relocation of Solar Power System to Easy Life Water Ventures The paper states that having an effective power source will help the organization operate smoothly and sustainably and increase its reputation.
• The Problem of Water Scarcity The paper states that although the problem of scarcity of water is severe, it is crucial to take measures to solve it since they can improve the situation.
• Aspects of Global Pollution of Water Global pollution of water resources has devasting effects on the environment that include the destruction of the ocean ecosystem and biodiversity.
• Biogeochemical Cycles: Carbon, Nitrogen, and Water The most common biogeochemical cycles are carbon, nitrogen, and water cycles. The purpose of this paper was to summarize these three cycles.
• Water Pollution in the Florida State The researchers claimed that plastic pollution was caused by the tourists and citizens who live along the coastline and dumping from the industries.
• Water Intake and Output: Mechanisms of Regulation For healthy function, the human body requires water balance as one of the key mechanisms, where the average daily water intake and output are relatively equal.
• Hyponatremia: How Much Water Do You Actually Need? Some schools, like Mississippi State, do hydration tests before each practice to ensure their players are adequately hydrated.
• Analyzing the Use of Water in Danticat, Roumain, and Marshall The use of water in the three novels Roumain’s “Masters of the Dew,” Danticat’s “Krik? Krak!” and Paul’s “Praise Song for the Widow” has a symbolic meaning.
• Water Pollution and How to Address It A person must protect nature – in particular water resources. After all, the possibilities of water resources are not unlimited and sooner or later, they may end.
• The Water Shortage Supply in Las Vegas The water shortage supply in Las Vegas is a major problem due to the city’s reliance on Lake Mead and Colorado Rivers, which are drying up due to droughts.
• Water Pollution: Effects and Treatment Pollution of water bodies is a serious hazard to humans and the aquatic ecology, and population growth is hastening climate change.
• Examining Solutions for Mitigating the Food and Water Security Issue Hunger, malnutrition, and decreased resource distribution manifest in communities having issues with food and water security, which decreases the well-being of individuals.
• Garbage Pollution’s Impact on Air, Water and Land Garbage pollutes the planet, and to stop this adverse effect, the authorities’ involvement is needed. One solution lies in the plane of economics and politics.
• The Issue of Food and Water Security The global issue for the analysis is food and water security. This is a topical problem nowadays, especially in light of climate change and population growth.
• Impact of Water Pollution: Water Challenges of an Urbanizing World Water is a source of life on Earth, and it is one of the very first needs of living beings. It is a vital resource for the development of the economic and social sectors.
• Environment: There’s Something in the Water Environmental racism hurts the natural image of landscapes and negatively affects the atmosphere and reduces the quality and duration of life for minorities.
• New Evian Water Product and Customers Analysis As the new Evian water product is a more ecological option, customers concerned about the environment could also represent the client base of the product.
• Solutions for Food and Water Security Issue With many nations encountering food and water security problems, the consequences of such events have become global, giving rise to multiple outcomes this insecurity.
• Evaluation of Articles on Food and Water Security The two resources chosen for this discussion pertain to food and water security solutions. The scholarly source is visually distinct from the popular source due to its structure.
• The Clean Water Network Support Statement Fresh water has become one of the most valuable resources in the world, around which regional or even global wars may occur in the future.
• Water Scarcity Due to Climate Change This paper focuses on the adverse impact that water scarcity has brought today with the view that water is the most valuable element in running critical processes.
• Global Societal Issue: Food and Water Security According to research, food and water security is a pertinent global problem in the current decade, with access to food and water becoming scarce in certain world regions.
• The High Heat Capacity of Water The heat capacity of water greatly affects the planet’s climate. At high temperatures, water absorbs heat, and when it gets colder, it gives it away.
• Exploring the Agenda for Fresh Water Supply in Remote Regions The fundamental thesis of this entire paper is that scientific and technological advances catalyze the development of technologies to deliver fresh water to remote areas of Texas.
• Food and Water Security as Globalization Issues Globalization has several implications for the business environment, among which are the expanded access to resources, and the interdependence of international companies.
• What Is Water-Related Terrorism and How to Cope With It? Water-related terrorism includes damaging government facilities, and since water resources are vital for human existence, it is profitable for terrorists to attack them.
• Whirlpool in the Sea off the Coast of Scotland Near Ayrshire Due to Waste Water Stunning drone images near Lendalfoot in South Ayrshire captured a glimpse of a mammoth whirlpool off the Scottish west coast.
• Causes and Risks of Water Pollution The paper describes the effects of water pollution on human health from the perspective of existing findings on this topic and the assessment of information.
• Safe Drinking Water: Current Status and Recommendations The study proposes the usage of agricultural waste as a sustainable biosorbent for toxic metal ions removal from contaminated water.
• The Problem of Environmental Pollution: Fresh Water One of the more important concerns that are fast becoming a major threat is pollution and no form of pollution seemed to be bigger than that of freshwater pollution.
• Underground Water Contamination in St. Louis Mo City In St. Louis Mo City of Missouri State, contamination of underground water is most likely and that is why the water supply is a subject to government policies.
• Basic Functions of Minerals and Water in the Body This paper discusses the functions and sources of minerals, the function of water in the body, and the general effect of dehydration on the body.
• Twitter Campaign: Impact of Water Runoff Water runoff can cause flooding, which means property damage and mold formation in damp basements and more. This paper is a twitter campaign about the impact of water runoff.
• Water Pollution of New York City Rivers The aim of the analysis was to assess the effects of CSOs on water quality and the environment at different sites along the Harlem River.
• Multidisciplinary Approach to Water Pollution This paper shows how the multidisciplinary approach addresses water pollution as a public health issue. It is important to understand what the model entails.
• Water Cooling Tower Construction Site’s Problems The paper highlights three major problems at the construction site. They are security, scheduling, and safety problems.
• The Problem of Environmental Water Pollution This paper discusses a public health concern by explaining the causes of water pollution, how it affects human communities, and the possible strategies.
• Cooling Water System Overview Water towers can reduce temperatures more than any other devices using air only to reject heat hence are more cost-effective.
• Recent Water Treatment and Production Developments This study attempts to investigate whether inorganic filters are more suitable for industrial and water treatment processes when compared to organic filters.
• Chemistry: Partitioning Coefficient of the Water The partitioning coefficient of the water solutions with of diuron, decadienal, atrazine, fluoranthene, and desethylatrazine compounds are calculated in accordance with the formula.
• Study of Local Water Resources Quality This laboratory report aims to summarize the results obtained during the study oxygen consumption, BOD, and detecting dissolved suspended solids in Hong Kong water.
• Developing Suspension Carbon Nano-Tubes in Water This paper has discussed nano-tubes and suspension as well as stabilization which make use of Multi-Wall-Carbon-Nanotubes by the function of concentrated SDS.
• Is Bottled Water Dangerous for People and the Environment? The purpose of this paper is to discuss alternative perspectives on bottled water and whether it is dangerous for people and the planet.
• A Cartographic History of Water Infrastructure and Urbanism in Rome The freshwater available to the city was a huge cultural and economic boon to Roman citizens. Some of this ancient water infrastructure is operational to this day.
• Integrated Water Strategies From Website Water Recycling The website http://waterrecycling.com/ is a front-end of their company showing various services that the company offers in the field of water recycling.
• The Causes of Water Pollution Water pollution is a significant decrease in water resources’ quality due to the ingress of various chemicals and solid waste. The causes of pollution are related to human activities.
• Bottle Water Industry in Current Economic UK Climate The research question is whether bottled water is a necessity or a luxury with regard to the current economic climate in the United Kingdom.
• Water Quality Assessment. Environmental Impact Maintaining good water quality is essential to human health; thus, the recent decades have outstandingly worsened the water across communities worldwide by pollution.
• Political Ecology and Water Wars in Bolivia The given critical assessment will primarily focus on bringing a new perspective to the issue from the standpoint of political ecology.
• The Influence of Water on the Growth of Popcorn Plants The information from the study would aid farmers in identifying appropriate seasons to cultivate popcorn plants based on data of meteorological forecasts.
• Boiling Is a Process That Cools the Water This paper tells that bringing water to a boil while making tea is a progression that cools it since the process lessens the overall temperature.
• Water Conservation Practice in Olympia Olympia city has a comprehensive water conservation program that involves many projects. The city puts much effort into the conservation of water.
• Protecting the Current and Future Water Supply for Rio de Janiero In the current rate of use, as well as the consensus reached by the governing officials in Rio de Janeiro, there will be enough potable water until 2025.
• Water Quality and Supply The main problem on the way to the solution of environmental issues is a violation of generally accepted rules.
• Water Conservation Practice in Houston From the treatment of wastewater to the reduction of the consumption of the same Houston is an epitome of the increasing need to conserve resources, especially water.
• Burning Issue of Water Pollution in Washington The problem of polluted drinking water in Washington should be solved immediately despite various obstacles, such as pressure for money, etc.
• Drinking-Water in Third World Countries The shortage of drinking water in countries of Third World and the public controversy, surrounding the issue, illustrates the validity of this thesis better then anything else.
• Water: An Often Overlooked Essential Element in Our Environment The freshwater required for growing food and livestock is also in great demand by the large numbers of inhabitants in the world’s cities and towns.
• Bottled Water: Environmental and Cultural Impact The consumption of bottled water has an impact on society. Appropriate strategies must be implemented to ensure that the hazards associated with bottled water are reduced.
• Bottled Water Status in the UK With the current economic climate in the UK, the issue of whether bottled water has become a luxury or a necessity.
• Changes in the Global Water Cycle Changes in the climate brought about by global warming have a much bigger likelihood of impacting negatively on the global hydrological cycle.
• Water and Soil Pollution: Effects on the Environment Water and soil pollution is the process of contaminating water and soil. In this project, we will investigate the apparent main pollutants of the Spring Mill Lake.
• Bottled Water: Culture and Environmental Impact Bottled water as a particular branch of industrial growth in countries throughout the world represents the source of environmental pollution.
• Alternative Energy Sources: A Collaborative Approach in Water Management With the increasingly high prices of gasoline in particular and fossil fuels in general there is a need to find an alternative source of energy.
• Water Sector Privatisation in Saudi Arabia The paper explores the decision by the Ministry of Water and Electricity in Saudi Arabia to form the National Water Company to facilitate the privatization process and oversee the regional operations.
• Polycyclic Aromatic Hydrocarbons Effect on Water Polycyclic aromatic hydrocarbons (PAHs) constitute one of the largest groups of compounds that produce widespread organic environmental pollution posing a risk to marine biota
• Lack of Water in California as an Environmental Issue California can run out of water because of technological and social problems that affected the region. Defining water resources’ “development” is critically important.
• Potential Threats to Water Supplies in Ottawa The purpose of the research is to identify the distribution of threats to drinking water in the city and determine who might benefit and who might be harmed in the process.
• Water Quality in Savannah, Georgia The City of Savannah Water Supply and Treatment Department conducts numerous annual tests to ensure that drinking water in the region is safe for human consumption.
• Water Pollution Index of Batujai Reservoir, Central Lombok Regency-Indonesia Despite having 6% of the world’s water resources, Indonesia’s environmental policies have not only been raising concerns but also pushed the country to the brink of water crisis.
• Dream Water Company’s Product Marketing The core product is the main benefit that the product brings to the consumer. For Dream Water, the core product is the medication against insomnia.
• Water Sanitation Program in Saudi Arabia In the Kingdom of Saudi Arabia, as the demand for water continues to increase without an equivalent increase in the supply, the level of hygiene may soon become a problem.
• “Bling H2O” Bottled Water in the Australian Market Bling H2O water is the world’s most expensive bottled water. The brand’s creator targeted to sell it to the celebrities who highly esteem their bottled water.
• FIJI Water Company’s Success The business owners of FIJI Water embarked on a very active marketing campaign aimed at the promotion of the water, as well as the establishment and maintenance of FIJI Water’s brand.
• Virtual Water Content and Global Water Savings The Virtual Water Content concept was the byproduct of discussions regarding the need to provide food in countries suffering from drought or plagued with perpetual water scarcity.
• Active Remediation Algorithm for Water Service in Flint The Active Remediation algorithm aims to inspect the water service in Flint, Michigan, and identify those lead pipes that need to be replaced by copper pipes.
• Water Savings and Virtual Trade in Agriculture Water trade in agriculture is not a practice that is unique to the modern generation. The practice was common long before the emergence of the Egyptian Empire.
• Virtual Water Trade and Savings in Agriculture This essay discusses the savings associated with virtual water trade in agriculture and touches on the effects of a shift to local agricultural production on global water savings.
• Virtual Water Trade of Agricultural Products Virtual water trade is a concept associated with globalization and the global economy. Its rise was motivated by growing water scarcity in arid areas around the world.
• Substances Influence on Water The objective of the experiment will be to find if the freezing rate of water changes when different substances are added.
• Virtual Water Savings and Trade in Agriculture The idea of virtual water was initially created as a method for assessing how water-rare nations could offer food, clothing, and other water-intensive products to their residents.
• Green Infrastructure in Water Management This paper evaluates the utility of water management in urban areas from the aspect of perception and interpretation of green infrastructure in water management.
• Third-Party Logistics, Water Transportation, Pipelines Transportation plays a crucial role in today’s business world. This work shows the benefits and limitations of third-party logistics providers, water transportation, and pipelines.
• Water Quality and Contamination In this paper, carries out detailed experiments on the bottled and tap water available to consumers to establish whether it is worthwhile to purchase bottled water.
• Water Buffalo Days: Growing Up in Vietnam by Nhuong The book Water Buffalo Days: Growing Up in Vietnam by Nhuong tells the story of a young boy in a central village in Vietnam. The story presents unique characteristics of Vietnam society and culture.
• Oil, Water and Corruption in Central Asian States The region of Central Asia has been a focus of the world’s political and economic attention due to its rich oil and gas resources. Corruption is the main curse of Central Asian states.
• Water Scarcity Issue and Environment The paper answers the question why to be worried about running out of drinking water even though the earth’s surface is mostly made of water.
• Environmental Studies: Water Recycling Different countries face varying challenges in as far as the provision of clean water to its population is concerned depending on its economic development level and geographic location.
• How Does Water Pollution Affect Human Health?
• Are Sports Drinks Better for Athletes Than Water?
• What Happens if You Don’t Filter Your Water?
• Can Game Theory Help to Mitigate Water Conflicts in the Syrdarya Basin?
• How Can We Reduce Water Scarcity?
• Are Water Filters Really That Important?
• How Much Water Do We Need to Feed the World?
• Why Is Water Important for Food Production?
• Can Markets Improve Water Allocation in Rural America?
• How Can We Reduce Water Consumption in Food Industry?
• Can Public Sector Reforms Improve the Efficiency of Public Water Utilities?
• What Are the Modern Technologies Used to Treat Water?
• How Does Water Pollution Affect Global Warming?
• Can Sea Water Generate Usable Energy?
• What Are the Steps Taken by the Government to Reduce Water Pollution?
• Can Sugar Help Lower the Freezing Point of Water?
• Do We Need More Laws to Control Water Pollution?
• Can the Global Community Successfully Confront the Global Water Shortage?
• What Is the Government Doing to Save Water?
• Can Virtual Water ‘Trade’ Reduce Water Scarcity in Semi-arid Countries?
• Does Urbanization Improve Industrial Water Consumption Efficiency?
• How Has Technology Helped Us Save Water?
• Does Piped Water Improve Household Welfare?
• Can Water Pollution Policy Be Efficient?
• How Does Green Infrastructure Improve Water Quality?

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469 Water Essay Topic Ideas & Examples

Looking for interesting topics related to water? This study field is broad, exciting, and definitely worth exploring!

🏆 Best Water Topic Ideas & Essay Examples

👍 top water essay examples, 📌 easy topics related to water, 💡 water essay topics, ✍ water topics for research papers, 🥇 interesting water topics to write about, ❓ essay questions about water.

In your essay about water, you might want to focus on water as one of the most valuable natural resources. Consider exploring the issues of water pollution, purification, conservation, or management. Whether you need to prepare an essay, a research paper, or a presentation, our article will be helpful. Here we’ve collected water essay topics and titles. Water essay examples are added to inspire you even more!

• Should Bottled Water Be Banned? Plastics is one of the products that are leading in polluting the environment. Plastics are detrimental to the environment; they affect the soil, water, air and eventually lead to climate change and global warming.
• Air and Water Pollution in the Modern World The high number of vehicles in the city has greatly promoted air pollution in the area. Poor sewerage system, high pollution from industries and automobiles are among the major causes of air and water pollutions […]
• Water Pollution: Causes, Effects and Possible Solutions This is why clean water is required in all the places to make sure the people and all the living creatures in the planet live a good and healthy life.
• Water Purification Process Since the process is aimed at eliminating all the impurities present in the water, it is necessary to apply chemical and physical methods of separation in an orderly manner.
• Water Scarcity as a Global Issue: Causes and Solutions Common causes of water scarcity include overpopulation e in regions that have limited water resources, global warming, destruction of water catchment areas by human activities, and pollution of water sources.
• The Process of the Water Cycle It is the primary process that drives the movement of water from water bodies into the atmosphere in form of water vapor.
• Water Recycling Recycled water is obtained from waste water and contaminated water that has been subjected to thorough treatment to ensure that it is proper for use for different purposes.
• Masafi Water Company and Al Ain Water Company Manufacturing of Masafi and Al Ain Water: The resource of Masafi water is the mountain and this is why the water is rich in minerals.
• Water Transport Systems in the World The development of the three and four Masted ships in the 16th century was a major event in the history of the water transportation system.
• Evian Water Company’s Analysis Due to the popularity of its water, the company managed to expand, and in 1978, it made its way to the market of the United States of America.
• Water Advertisement The waterfall in the background reinforces the psychological need for water and adds to the freshness of the advertisement and water itself.
• Water Cycle: Lesson Plan for 5th Graders The purpose of the program is to introduce students to the water cycle systems, stages, and importance. The student should be able to define and explain the water cycle stages.
• Water Pollution: Causes, Effects, and Prevention Farmers should be encouraged to embrace this kind of farming which ensures that the manure used is biodegradable and do not end up accumulating in the water bodies once they are washed off by floods.
• The Effect of Plastic Water Bottles on the Environment In addition, the proponents of plastic use have argued that recycling is an effective method of mitigating the effects of plastic to the environment.
• The Thematic Concept in Water Names Like the narrator, a reader may think that the story presents a happy ending, as the young woman “went to join the kingdom of her beloved”. The woman wants the girls to find the answer […]
• Water Resource Management: How to Save Water Resources We need to address the difficult problems of evaluating and protecting the global commons, which are complicated and interrelated while maintaining the free trade systems of the world.
• How Does Water Hyacinth Harm the Local Ecosystem? Water hyacinth Flowers Water hyacinth has great harm on the local ecosystem and affects aquatic life and water quality. The life of other plants and animals is jeopardized by the rapid growth of water hyacinth.
• Water Cycle Process On the reaching the atmosphere water molecules bond together again and come back to the earth surface through the process of precipitation.
• Determination of Quinine in Tonic Water with Fluorescence Spectroscopy In general, luminescence is understood as the glow of substances not accompanied by heat production but initiated by the absorption of photons.
• Accessibility to Safe Drinking Water The first is to dig wells in the rural and arid areas to aid the people to have access to water. The other alternative is to treat water and use it in the home.
• Water: Nature’s Gift to Humanity However, the role of this element is not only in the formation of life but also its maintenance since this seemingly ordinary liquid plays an enormously essential role in the existence of the human and […]
• Water Scarcity and Its Effects on the Environment The core objective of this research paper is to examine water scarcity and its effects to the environment. This is because sufficiency of water supply depends on water conservation methods, distribution channels available in the […]
• Water Quality Importance In a lot of areas, the water available to the public is contaminated; that is it has substances that can be of great harm to public health.
• Coca-Cola India and Water Pollution Issues The first difficulty that the representatives of the Coca-Cola Company happened to face due to their campaign in the territory of India was caused by the concerns of the local government.
• Diet and Water as an Overlooked Essential Nutrient Water is a very important nutrient in the body because it maintains homeostasis, and enhances the transport of other nutrients and minerals from their point of absorption to other parts of the body.
• Sustainability: Domestic Water Usage Much of the hot water is used when cleaning and washing, with the shower making up to 43% of the 41 gallons and washing clothes making up to 29%.
• Water & Air Pollution and Health Issues in Brazil The main environmental effects of pollution include the destruction of marine habitats, water scarcity, and anoxia. The conclusion is informative because the writer includes strategies to alleviate the problem of air and water pollution in […]
• Saving Water and Methods of Its Protection That is, the plan will effectively manage the water usage at the current state of the company as well as in the future. If protection and conservation of water is not done, there will be […]
• The Effect of pH on Water Holding Capacity of Chicken In the present laboratory work, the main issue is to investigate the potential relationship between WHC as a measure of moisture content and chicken pH; specifically, the question is to identify the effect of meat […]
• Muslim Civilisation: The Mechanical Water Clock of Ibn Al-Haytham This forth stage is the one that determines the survival of the state, as the society is already discontented with the rule, hence disintegration of the state.
• Environmental Impact of Bottled Water The process of manufacturing the water bottles, such as the dependence on fossil fuels, is causing a lot of direct as well indirect destructing to the environment.
• People Affected by Fires and Natural Disasters Need Help With Food, Water, Shelter Today, I would like to talk to you about natural disasters and how to minimize their impacts by contributing to charity funds, and how your contribution can make a difference.
• Modern Water Purification Methods for the Middle East In this study, we will learn about the methods of water purification and the need to purify water. The specific purpose of the study is to describe and explain the methods of water purification in […]
• Integrated Sustainable Water Management in the UAE The UAE Water Security Strategy 2036 was unveiled by the Ministry of Energy in 2017 to ensure that access to water during an emergency and normal conditions are sustainable within the internal standards, local regulations, […]
• Water Pollution in the Philippines: Metropolitan Manila Area In this brief economic analysis of water pollution in Metro Manila, it is proposed to look at the industrial use of waters and the household use to understand the impact that the population growth and […]
• Water Consumption on the Household Level The specified phenomenon can be explained by the fact that controlling the use of water in the course of taking a shower is quite complicated for most people.
• Third World War Will Be Over Water The severity of the case of water scarcity can be best explained by the inclusion of the problem of water as one of the main goals of one of the greatest development frameworks in the […]
• Fiji Water Strategic Analysis The second alternative could involve the idea of putting underground and sea bed pipes to facilitate the transportation of the water commodity from Fiji to the lucrative international markets, such as the US.
• Water Purification in Saudi Arabia The scope of this report is to bring out all sorts of features used for water purification in Saudi Arabia and their effectiveness in providing pure water in all regions of Saudi Arabia. Desalination is […]
• Water Conservation and Drought Issues in Resorts The idea of the conservation of natural resources and water, in particular, became popular in the previous century. The understanding of the need for nature protection commenced in the 1960s.
• Tipperary Mineral Water Company In addition, consumers’ desire to lead a healthy lifestyle has greatly increased the market growth and demand for mineral water by a rate of 8. The main consumers of mineral water in this market are […]
• Water Quality Report: Overview Water quality reports provide information in regards to the quality of the drinking water, possible contaminants, and ways to reduce risks.
• Synopsis of “Water” Short Story by Lee Hoffman From the story it is clearly indicated that, Evan was very disappointed with what Redmor treated the people of this area; and decided to take a ravage especially because his friend Hank was shot.
• Water-Saving Technologies in the Middle East Our planet is made of 70% water and yet most areas of the world are without water. However, to conserve the cost of this important resource, certain steps are being taken by the respective governments […]
• Water Shortage’ Major Causes and Implication Summary of the article This article is a discussion regarding one major problem that is an issue of concern in the 21st century which according to the author, the world is currently facing a major […]
• Analysis of Lab: Heat of Fusion of Water In this experiment, information was collected regarding the mass of the calorimeter and bowl, the mass of the empty calorimeter, the water, and the contents: all raw data are shown in Table 1.
• Seawater vs. Brackish Water Reverse Osmosis The concentrations of seawater and brackish water differ considerably; hence, there is a distinction involving the concentrate acquired from seawater desalination plants and brackish water desalination plants.
• Anomalous Expansion of Water: A Home Experiment This investigation proves the hypothesis that water expands anomalously when cooled and increases in volume as it nears its freezing point of zero degree Celsius.
• Dehydration and Importance of Water There are plenty of fluids in the body that mainly consist of water; one of these is saliva. Water also transports oxygen from the lungs to other parts of the body that are in need […]
• Fire and Water Symbols in “Sula” by Toni Morrison Water and fire are used by the author as symbols of destruction and purification respectively, which allows the readers to better understand the main characters in the context of the communist oppression.
• Water’s Role in Society and Its Applications The water table is forced higher by a dam to intensify the force of the water’s descent. In the future, water should be modified to act as a source of fuel for different machinery to […]
• Flow: For Love of Water Regardless of the level of awareness and the intentions to study the world around, not many people comprehend how dangerous and life-threatening the lack of water can be.
• The Documentary Film “Flow: For Love of Water” First, the issue in question is in direct relation to the welfare of the entire planet’s population, and the film makes a convincing case that there are reasons to worry. In the end, I believe […]
• Bottled Water Industry and Aquafina Another reason of the boom in the consumption of bottled water is its taste because a large number of people prefer its taste to that of tap water.
• Providing Access to Clean Water This is why this option should be overlooked by coastal communities that can significantly increase the amount of clean water which is available to them.
• Rainwater Harvesting to Replenish Underground Water in India Due to the increased rates of deforestation in Rajasthan monsoon, rains started to wash down the surface levels of the soil, making the ground less fertile and eroded.
• Water Resources: History and Potential Impacts The quality of our water resources depends on many factors that include but not limited to; flows, the rate and the timing of run offs, and the ability of water sheds to assimilate wastes and […]
• Demo Park Water Administration Project Management In this assignment, the main areas for group work were the creation of a project plan and the identification, as well as the demonstration of its importance.
• Availability of Water Resources in United Arab Emirates This has led to the reduction in the ground water levels and the quality of water. Rainfall is the main source of water in the United Arab Emirates.
• Roman Aqueducts “The Relevance of Water to the Social Political Climate of the Roman” The main question in this paper is: what were the names and functions of the aqueducts in ancient Rome? The need to build aqueducts in Rome was prompted by the need for mass supply of […]
• The Flint Water Crisis From Marxist Perspective To understand the causes of the crisis and ways to prevent such problems in the future, it is possible to employ the Marxist approach.
• Effect of Sea Water and Corrosion on Concrete On the other hand, substantial tautness, for instance due to meandering will shatter the tiny firm pattern, ending up in fracturing and disjointing of the concrete.
• Domestication of Water: History of Swimming Pools One of these techniques was the creation of swimming pools, special structures that hold the water and can be used for swimming and leisurely activities.
• Turbidity and Total Suspended Solids of Water: Lentic and Lotic Sites In answering the research question, the objective of the study is to compare the quality of water in the lentic system and the lotic system.
• Dubai Electricity and Water Authority’s Employees The paper will seek to determine the primary reason for the symptoms indicated by DEWA’s HR staff and to provide recommendations for action to improve the current situation.
• Pure Home Water Company: Business Model The implementation of the business model will make a significant impact on a serious problem of the modern world. The business model is motivated by a very strong social aim, and it should make various […]
• Marketing Plan for Water Sensitive Nail Polish This part presents the information collected in 2014 as the company focuses on the demand behavior of the new nail polish.
• Water Shortages in the World Management of water supply in developing countries is poor as compared to that of developed world. In addition, pollution of water in developing countries is quite prevalent as compared to that of developed world.
• Water Quality and Treatment The main objective of this paper is to identify the main impurities in water that pose threats to the health of households.
• Key Factors of Competitive Success in the Water Bottling Industry The introduction of enhanced or functional water products, by a number of major bottling firms such as Coca-Cola and PepsiCo, has provided further competition, threatening to squeeze profitability for them.
• Water Distribution System in Spain The first river basin agencies were created in the Ebro basin and in the Segura basin in 1926, followed by the Guadalquivir in 1927 and the Eastern Pyrenees in 1929″.
• Water Properties as a Solvent: An Experiment Lab In the second part of the work, a mixture of 10 g of solid calcium hydroxide and 50 mL of drinking water in a beaker was initially created.
• Water Resources’ Quality in the Southwestern United States To understand the importance of the issues of drinking water quality and availability in the Southwestern United States, factors such as local climate, population changes, consumption of local and imported water, wastewater treatment, and recycling […]
• The Hydrologic Cycle and Water on Earth The amount of water molecules in the earth is constant although the motion of water is continuous. It flows along the eastern of the Japanese coast, bends towards the east, and completes the loop as […]
• The Issue of Bottled Water Consumption The steady rise in the demand for bottled water is causing hips of unnecessary garbage and resulting in the consumption of vast quantities of energy according to the report by Earth Policy Institute.
• Drinking Water and Culture in the Valley of Mexico The book A Precious Liquid: Drinking Water and Culture in the Valley of Mexico written by Ennis-Mcmillan reveals a story about the way residents of a small Mexican village manage the water deficiency, but in […]
• Water Resources and Usage The stressors that threaten human water security An analysis of the worldwide status of water as a human resource has been limited to the fragments of regional and state based assessments that show varying indicators […]
• Water Resources in Economic Proposals on the economics’ of water resources FAO states, the escalating responsiveness that water shortage has brought forth the acceptance of the opinion that “water is an economic good” as one of the four Dublin […]
• Water Pollution in a Community: Mitigation Plan Though for the fact that planet earth is abundant with water and almost two-thirds of the planet is made up of water still it is viewed that in future years, a shortage of water may […]
• Irrigation Water Reduction Using Water-Absorbing Polymers Moreover, Abu Dhabi city acts as both the capital of the country and that of the emirate. This encouraged more people to take on agricultural activities to help boost food and animal production in a […]
• Motivations to Choose Bottled Water The growth of the bottled water industry is attracting a lot of global attention because more companies are jostling to have a significant share of the market.
• Water Pollution and Management in the UAE The groundwater in UAE meets the needs of 51% of users in terms of quantity mainly for irrigation. Surface water is the source of groundwater and plays a major role in groundwater renewal.
• Water and Environment Engineering The village is situated in the Northwestern part of the state, near the seacoast. However, one of the village residents made an offer to the turtle and the latter allowed humans to use water from […]
• Fiji Water: A Comprehensive Analysis The paper is analytical in nature and it displays some of the aspects that make the product unique and relevant in the market, some of the challenges that the product’s company encounters, how the company […]
• The Water System: Rivers, Streams and Lakes The techniques used to compare rivers in the world involve an analysis of the size of the drainage area, the length of the main stem and the mean discharge.
• Como Agua Para Chocolate: Like Water for Chocolate At the end of the film, they finally find a way to be together, but after marriage Pedro dies and Tita kills herself.
• Mud Lick Creek Project – Fresh Water Pollution This potential source of pollutants poses significant risks to the quality of water at the creek in terms altering the temperature, pH, dissolved oxygen, and the turbidity of the water.
• Water Quality Issues in Developing Countries According to WHO, the quality of drinking water is a foundation for the prevention and control of waterborne ailments, thus water quality is a critical environmental determinant of health for populations using the water.
• Pre-Construction Design Specifications: Water Piping Sub-System The criteria of complexity and implementation are related to the flexible PDS criteria of the system being powering set-up, repeatability of measurement, reduced temperature setup time, and progressive heating/cooling supply temperature.
• The Physical and Chemical Properties of Water Considering the structure in the figure above, it is evident that a molecule of water has a line of symmetry that can be traced through the water molecule, acting as a bisector of the angle […]
• Visiting Black Rock Water Reclamation Plan Generally, it appears that the Black Rock Water Reclamation Plant seems to be one of the most interesting productions of its kind on the reason of implementation of a row of environment protecting technologies and […]
• Natural Sciences: Water Expansion During Freezing The review of the structure of water molecules shows that it has two atoms of hydrogen and one atom of oxygen.
• Dialysis Water Treatment System Heat exchanger: the evaporated water from the boiler is passed through the heat exchanger where it loses heat to the working fluid/feed water in the heat exchanger.
• Can Hot Water Freeze Faster Than Cold Water? Project Goals To analyzed the mechanisms fronted in the quest to finding the cause of Mpemba effect. A data on the actual lose in volume of water need to be tabulated for analysis.
• Water Consumption in the World The results of the investigative study into the daily water usage within households in Abu Dhabi show a mean average of 135 gallons/per day for the 15 households that were involved in this project.
• Green Buildings and Their Efficiency Water Consumption The resources are useful in terms of provide regulation of buildings, components of green buildings, selection of green materials and where to purchase such materials.
• Causes of Water Pollution and the Present Environmental Solution Prolonged pollution of water has even caused some plants to grow in the water, which pose danger to the living entities that have their inhabitants in the water.
• Environmental Science: Smart Water Management Among the essential elements in human life is water, which is required for maintaining the water balance in the body and for cleanliness, as well as for many economic sectors, from agriculture to metallurgy.
• Systemic Effects (Risks) of Water Fluoridation: Fluoridation Assignment Fluoride contributes to teeth development depending on the site where it is applied and the mode of entry into the system. Thus, proponents argue it is one of the safest and most effective solutions to […]
• Ineffective Water Resource Management in the Hotel Industry In the context of the problem of water overuse for service production and revenue generation, the most appropriate type of assessment is a water audit.
• Innovations on Energy and Water Co-Benefits In addition, the number of harmful emissions that are harmful to both people and the planet will be significantly reduced. The introduction of social innovations is to develop strategies that will solve social problems.
• The Himalayan Melting Glacier Contribution to Water Scarcity in Mount Everest Planetary phenomena such as the tilt of the Earth, its distance from the Sun, temperature, and atmospheric cycles belong to the first category.
• Food and Water Shortage: The Negative Effects As a result, one of the biggest challenges in the 21st century is the food and water shortage, which might lead to violence and the death of many people.
• Sustaining Our Water Resources: Pharmaceuticals in Water Supply The presence of pharmaceuticals in the water supply is primarily harmful to fish and aquatic wildlife as they may impact the hormone system of living creatures, causing reproductive failure.
• The Article “Where the Water Goes” by David Owen This paper highlights misconceptions about the drying of lake Mead, the importance of the Colorado River, and the causes of its scarcity in Las Vegas.
• Cashion Water Quality: Spatial Distribution of Water Pollution Incidents This essay discusses the quality of water as per the report of 2021 obtained from the municipality, the quality issue and the source of pollution, and how the pollution impacts human health and the environment […]
• Plan Elements for Sustainable Management of Water Resources It was taken into account because it provides greater imperiousness, where the rising development of Arzaville community structures and roadways disrupts the local water cycle and floods bays and guts with significant amounts of stormwater […]
• Clouds: The Water Cycle and Social Sciences As a result, when the weight increases and the droplets grow, they are released in the form of precipitations. Moreover, the movement of the water can be applied to a sociological element.
• Water Pollution as a Crime Against the Environment In particular, water pollution is a widespread crime against the environment, even though it is a severe felony that can result in harm to many people and vast territories.
• Water Contamination Issue in Medical Anthropology The role of water is so important that any economic or political disturbance can result in the worsening health problems of the population. The most recent and evident example of the failure in disease management […]
• Water Consumption and Sleep Hygiene Practices First, I will discuss that safe and sufficient water facilitates the practice of hygiene and well-being and is a critical determining factor for health.
• Understanding the Water Regulations in Kenya The Constitution, therefore, mandates the national government the role of ensuring that all the water resources, including the international waters, are well managed and utilized to better the lives of the citizens in the nation.
• India’s Water Supply Improvement Plan In India, the concept of a “water crisis” is firmly established, and the future of the country largely depends on how it will be possible to dispose of the available sources of fresh water.
• Water and Energy Problems in Mining Industry The goal is to find and recommend solutions for mining companies to easily access quality ore deposits in inaccessible areas. According to the second interviewee, accessibility to water and electricity are among the major challenges […]
• The Water Treatment System Project The purpose of this project was to create a water treatment system that will allow for establishing and maintaining the provision of high-quality drinking water. In turn, the second part of the project includes information […]
• Sustainable Development and Water-Food-Energy Nexus in Sweden The Food and Agriculture Organization of the United Nations states that the securities of food, energy, and water are interconnected and depend on each other.
• Water Quality Issues: Case Study Analysis The quality of water is an essential part of the infrastructure of a city or state, which affects the health of the population and the level of well-being.
• America’s Growing Clean Water Crisis and the Resulting Diseases The current water crisis in Flint, Michigan, has focused a lot of attention on the state of water infrastructure. Lastly, there will be a not adequate amount of water to help in dissolving the nutrients […]
• The Sea Water Impact on the Human Cell Hence, consuming it causes a high amount of salt without the human cell, which leads to a steep concentration gradient within the cell, thereby causing water to be drawn out, which is detrimental to the […]
• Factors of the Water Crisis in Flint, Michigan The factors that caused the water crisis in this city can be considered negligence of the authorities, ambiguous and contradictory instructions of environmental protection agencies, and corruption.
• Increasing Global Access to Clean Water and Sanitation As noticed by researchers, innovative solutions to achieve global clean water and sanitation are needed, and the positive partnership of various organizations and groups from different spheres and levels may help with this task.
• Environmental Racism: The Water Crisis in Flint, Michigan The situation is a manifestation of environmental racism and classism since most of the city’s population is people of color and poor. Thus, the water crisis in Flint, Michigan, is a manifestation of environmental racism […]
• Flint Water Crisis: Municipal Water Supply System The city of Flint was a thriving industrial center in the third quarter of the last century; however, it had economic difficulties due to the closure of several General Motors factories in the 1980s and […]
• The Flint Water Crisis and Its Impact The contaminated water has lead to a number of diseases and disabilities, which, in turn, has left the city’s population with a large number of healthcare bills. In conclusion, the Flint Water Crisis is an […]
• Overcoming Shortage of Drinking Water It is also possible to process saltwater into freshwater, which is the most promising way to solve the problem of water scarcity.
• Financial Attractiveness of Domestic Solar Hot Water Systems: Article Review The peculiarity of the article is that the study of the authors aims to resolve urgent needs by increasing the demand for goods.
• Singapore International Water Week A good example of these conferences is the Singapore International Water Week and it forms the basis for this detailed report The SIWW 2022 brings together professionals, technocrats, and government leaders to share their experiences […]
• The Safe Drinking Water Act 1974: The Main Concept The act also directs EPA to report on the eminence of drinking water in the U. The SDWA calls for the EPA to publish an annual report on the drinking water in the US.
• The Safe Drinking Water Act 1974: Overview The main provisions in this law were to ensure that water supplied from the source to the faucets was free from natural and artificial contaminants through water treatment and consistent supply to the public.
• Is Tap Water Better and Safer for People and the Environment Than Bottled Water? In this study, I have decided to explore if tap water is better and safer for people and the environment than bottled one. Further, I will look at the impact of bottled water on people […]
• Importance of Mercury Water Pollution Problem Solutions The severity of the mercury contamination consequences depends on the age of the person exposed to the contamination, the way of contamination, the health condition, and many other factors.
• The Influence of Water Quality on the Population of Salmonid Fish It is expected that populations of wild salmonid fish may decline rapidly due to water pollution instead of farmed species because the effects of water pollution are deleterious.
• Case Study: Human Body Water Balance Sodium is reabsorbed in the thick climbing appendage of the loop of Henle. The rest of the Na+ retention happens in the distal nephron.
• Typical Reasonably Homogeneous Equilibrium in Water It is important that the diffusion coefficient used to link the iodine concentrations in one phase to that in another account for the existence of iodide and polyiodide salts.
• Creative and Critical Thinking in Case of Lack of Water In order to identify the significance of creative and critical thinking in the situation presented, it is necessary to dwell on the definition of the process of creative thinking.
• Water Scarcity in Africa and Mental Disorders Partially, the reason for the lack of meaningful changes in the policies preventing the causes lies in the social stigma towards patients with mental problems.
• Concept of Water Companies Furthermore, in this market formation, it is assumed that the prices do not control the market, which is contrary to the search for a life partner.
• The Safe Drinking Water Act: The Discussion Post The discussion post acknowledges that the Safe Drinking Water Act has remained a powerful guideline that must be followed by different stakeholders to ensure quality and clean drinking water is available to the greatest number […]
• Dehydration and Water in People’s Life It is of utmost importance since it cannot be stored in the body and replenishing of the water must occur constantly.
• Energy and Air Emission Effects of Water Supply Contemporary systems meant to heat water/air explore both the heat pumps and the solar plates that are combined to form a unit with the aim of optimizing on the energy efficiency as well as solar […]
• Adjustable Speed Drives Improving Circulating Water System This was concluded to be because of the many vortices that were generated as a result of the hindrance in the flow of water due to the shape defect.
• Oil and Water Flow in a Petroleum Reservoir While the physical model is to the scale of the original reservoir’s dimensions, a mathematical model is different. The mathematical model allows one to learn the fluid flow equation without having to develop a laboratory […]
• Behavior Change: More Water, No Coffee By the way, this was the first day when I did not feel any lack of energy due to the lack of coffee.
• Efficient Solar Refrigeration: A Technology Platform for Clean Energy and Water Refrigeration cycle capable to be driven by low grade energy, substituting gas-phase ejector used in conventional mechanical compressor.
• Salt and Drinking Water Shortage Therefore, humanity could reveal that given that the salt would not be willing to negotiate, it is possible to extort the water from the Martians as the resources of Earth are not as essential.
• Flint Water Crisis: Environmental Racism and Racial Capitalism The Flint crisis is a result of the neoliberal approach of the local state as opposed to the typical factors of environmental injustice; a polluter or a reckless emitter cutting costs. The two main factors […]
• Oil-Water Separation Techniques in Qatar’s Desalination Plants In many areas of the Middle East, the proper functioning of the vital social mechanism depends on the stable supply of fresh water.
• Annotated Bibliography on Water Management The importance of water management and its application in the oil industry is the primary focus of Adham et al.in this article.
• Recycled Water – Is It Safe for Drinking? There are a number of barriers that always work against the desire to obtain safe drinking water from recycling plants.
• Remote Sensing Monitoring the Ground Water Quality The overall view of the water quality index of the present study area revealed that most of the study area with > 50 standard rating of water quality index exhibited poor, very poor and unfit […]
• The Consequences of Using Tap and Bottled Water Using the word ‘walking’, the professor means searching for the required information, while ‘talking’ is a dialogue with the authors of the sources.’Cooking’ is implementing the information in the paper to achieve new conclusions, and […]
• Thirstier Mineral Water: Australian Market Analysis Due to the demand of the pure water, a group of students carried out research to come up with a natural drinking mineral water to meet Australian population demands.
• The Health Condition of Water Filtration for the Prevention of Gastroenteritis The medical care authorities prescribe that to lessen the danger of burning-through dirtied or defiled water is satisfactorily sifting water prior to drinking. The properties of the water channel should be checked to ensure that […]
• Marketing of the Bottled Water Industry in the US The growth of the industry can then be attributed to the level of comfort that people have become accustomed to. The bottled water industry is a feasible option for investors who would like to concentrate […]
• Abu Dhabi Water and Electricity Authority The subject of the contract is the performance of construction works by Contractor for ADWEA. The term of the contract includes the time needed to execute and complete all works.
• Proper Water Flow Requirements In order to ascertain the proper flow of water, standard typical sprinkler testing should be carried out on all the established water systems.
• Water Scarcity Problem in Sub-Saharan Africa Since the world has water in abundance, it is necessary that more be done to address the shortage of clean water.
• Anglo American PLC: Water Usage Sustainability Anglo American PLC, which is a well-known mining company operating as the second-largest mining company in the industry, intends to embellish the rate of sustainability to retain its global position in the critical competitive mining […]
• Newark Water Crisis: Water Pollution Problem The main problem was rooted in the fact that lead levels in the drinking water were highly elevated, which is dangerous and detrimental to the population’s health.
• Water Quality and the Water Board Scenario As a member of this water board one first needs to find out the level of quality of water and its source before the eruption of the drought, the clear cause of water shortage, impacts […]
• Water Fluoridation Plant Analysis
• Determination of M2+ Ions in Mineral Water
• House Energy Audit: Water and Energy Consumption Review for the House
• Woburn’s Municipal Water Supply System
• Toxicology: Is Water a Toxic Substance?
• The Effects of a High Consumption of Water
• FIJI Water: The Leading Producer of Bottled Water
• Biorefinery Processes and Products (Microalgae and Water Hyacinth)
• Water-Absorbing Polymers: Review
• How a Desalination Plant Removes Salts, Minerals From Water
• Water for Environmental Health and Promotion
• Conventional Water Treatment
• Water Supply and Sanitation Systems Devikilum Village
• Reduced Flow of Stream Water
• “Nutrient Water” Type Drinks and Whole Milk: Evidence-Based Claims
• Women Groups in Ikombe County: Water Tanks Delivery Funding
• Parent Purchase Bottled Water
• Designing a Controlled Water Cooling System
• Warm Water and the Characteristics of Plaster
• Aquadaf Technology – High Rate Water Clarification
• Fluoride in Drinking Water, Its Costs and Benefits to Oral Health
• Water Desalination in Saudi Arabia
• Irrigation Water and Carbon Footprint
• Domestic Water Usage Monitoring System
• Nutrition: The Importance of Water for Daily Life
• Water Policy Design in Toronto
• Landscaping Membranes for Oil-Water Separation
• Water Treatment System for Saline Bores in Cape York
• Testing the Safety of Water in Canada
• The Mega Corporation: Clean Water
• Clean Water Change the Lives of People in Developing Countries
• Privatization of Water in St. Louis
• Finance for Drinking Water Infrastructure
• BP: Water Use in Oil and Gas Industry
• Water Scarcity: Industrial Projects of Countries That Affect the External Environment
• Mapping Environmental Justice: Water and Waste Management
• Virtual Water and Water-Energy-Food Nexus
• California and Water Shortage
• Water Policy: The Impacts of Water Trading
• Water Consumption by Individuals and Households
• Water Services and Fire Fighting in Maryland
• Water Service in the UK: History and Sources
• Water Distribution in California
• Bling H2O: Brand of Mineral Water
• Western Region Water Corporation’s Analysis
• Water: The Element of Life
• Water and Energy Requirements of Curcubita Maxima
• 321 Water as a Bottle With a Built-in Filter
• Energy, Water and Capital as Factors Influencing Business
• Water Purification: Process and Other Nuances
• Thomas Cole’s Revelations Through Landscape and Water
• Thames Water Company’s Pollution Issue and Ecocentrism
• Las Vegas Water Shortage
• Modern Global Issues: Drinking Water Shortage
• Sharjah Electricity & Water Authority’s Creative Improvement Strategies
• Water Pollution: OIL Spills Aspects
• Liquid Waste Disposal and Ground Water Contamination
• Polluted Water and Human Diseases
• Market Analysis of Bottled Water
• Water Efficiency in Food Production: Food Security, and Quality of Life
• Food Distribution and Water Pollution
• Water, Energy and Food Sustainability in Middle East
• Food and Water Access. Human Security Perspective
• Environmental Policy: Water Sanitation
• Masafi Alkalife pH9 Water Advertisement
• The Ongoing Problem of Lead in Drinking Water in Newark, New Jersey
• Jordan’s Water Crisis and Response
• Water and Its Role in Biochemical Processes
• Baja California Water Crisis and Its Impact
• Columbia Roxx Water Company: Operations and Management Plan
• Water Shortage in Somalia: Reasons and Solutions
• Dubai Electricity and Water Authority’s Internship
• Fiji Water’ Environmental Effects
• Bolivian Water Price Determination
• Energy and Water Projects in the Middle East and North Africa
• Public Water Supply System in New York
• Website Usage: Bottled Water Company in Nigeria Case
• All the Water on Europa: Astronomy Picture of the Day
• Battled Water and Jewelry: Product Analysis
• Water Management: Soft-Path Approach in Abu Dhabi
• Integrated Sustainable Water Resource Management
• Heavy Crude Oil Emulsification in Water
• Year-Round Water Access in South Asian Countries
• Dubai Electricity and Water Authority: Sustainable Management
• Dubai Electricity and Water Authority’s Strategic Options
• Trends in Water Supply and Sustainable Consumption
• Best Water Management Practices
• Water Management: Best Practices
• Water Maze Experiment for Hydergine Drugs Testing
• Privatized Kuwaiti Ministry of Electricity and Water
• Abu Dhabi Climate, Water Usage and Food Production
• Chemical Contamination of Ground or Surface Water
• Water Billing IT Solutions Company Business Plan
• Nuclear Magnetic Resonance and Water Quality
• Dubai Electricity and Water Authority’s Tech Innovations
• Dubai Electricity & Water Authority’s Asset Lifecycle
• Dubai Electricity & Water Authority’s Cost Management
• Drinking Water Distribution System
• The Chippewa Cree Tribe’s Water Rights
• Tribal Water Rights and Influence on the State Future
• Water Quality as a Concern for Urban Areas
• Solar-Powered Water Cooler System
• How Saudi Arabia Can Overcome Economic Water Crisis?
• Water Pollution and Associated Health Risks
• California Water Shortages and Long-Term Solutions
• Lake Erie Water Pollution
• Dubai Electricity and Water Authority: Consultation
• Preserving of the Drinkable Water Worldwide
• American Water Company: Users and Systems Specialists Role
• Water Price Hike and Its Effects on the UK Economy
• Water Crisis Resolution and Investments
• Food and Water Quality Testing Device
• UAE Federal Electricity and Water Authority’s Policies
• Water and Soil Resources Issues in the Middle East
• Mountain Valley Spring Water Advertising
• Sunflower Plant Growth With Minimal Water Requirements
• Pure Home Water Company’s Environment
• Disposable Water Bottle Usage by Youth Population
• The Gardens of Islam: Water and Shade
• Water Cycle and Environmental Factors
• Potable Water Supply in the Gulf Region
• The Jordan River Water Issues and Hydropolitics
• Water-Energy Nexus Explained
• Water Pollution in the US: Causes and Control
• Water Control Issue in the United Arab Emirates
• Food and Water Waste Disposal in NYC
• The Water Cube Project and Design-Build Approaches
• Dubai Electricity and Water Authority: Employee Performance
• Importance of Water in Economics: Uses, Pollution, and Sustainable Growth
• Barwon Water Company’s Management and Service Analysis
• Water Transportation Industry’s Impact on Wildlife
• The Nile River: Water Issues and Hydropolitics
• Sustainable Strategies in Water Quality Control
• Water Crisis, Oceans and Sea Turtles Issues
• Sharjah Electricity & Water Authority’s Customer Satisfaction
• Abu Dhabi Water & Electricity Authority’s Pre-Assessment Audit
• EPA Rules Effect on Perchlorate in Drinking Water
• Quality Management of the Dubai Electricity and Water Authority
• Abu Dhabi Water and Electricity Company’ Demand Forecasting
• Environmental Health: Lead Exposure in Water
• The Human Right to Water: History, Meaning and Controversy
• “Vitamin-Enriched” Bottled Water: PEST Analysis
• The Water Nexus Model in the UAE
• Water Related Conflicts in Africa
• Clean Water Problem in Singapore
• Water Paradox: “The Wealth of Nations” by Adam Smith
• Water Scarcity, Marketing, and Privatisation
• Reduce Chemical Spills by Using Green Water Purification
• Reducing Chemical Contamination on Water
• Effective Methods to Increase Water Quality
• Abu Dhabi Water & Electricity Authority’ Quality Planning
• Water Resources Ecology: Current Issues and Strategies
• Blue Gold: World Water War Documentary
• Thirstier Mineral Water – Marketing
• Safe Drinking Water Importance
• Mars: Water and the Martian Landscape
• Saving Energy Systems: Water Heater Technology
• Jordan River’ Water Issues and Hydropolitics
• Water Symbolism in Christianity and Islam
• Banning Hosepipe Use as a Poor Solution to a Water Shortage
• Criminology: Water Boarding Torture
• Blue Gold: Global Water Crisis
• City of Newark Public Water Supply System
• Irrigation and Sustainable Water Use for Improved Crop Yield
• Environmental Studies: Water Contamination in China
• Is Bottled Water Ethical?
• Kantian Perspective on Water Privatisation
• Water Purification Process
• Water Quality & Drinking Water Treatment
• Kant’s Philosophy: Water and Ethics
• Water Pollution and Its Challenges
• The Three Methods of Water Supply
• Drinking and Bathing Water in Sabah
• Project Management: Sydney Water Company
• Perchlorate in Drinking Water
• Impact of PPP Projects in Energy and Water Sectors in the MENA Region
• Potential Reduction in Irrigation Water Through the Use of Water-Absorbent Polymers in Agriculture in UAE
• Water Pollution Sources, Effects and Control
• Water Resources Deterioration Consequences in the GCC Countries
• Society’s Impact on Water Recourses
• Effects of Lead and Lead Compounds on Soil, Water, and Air
• Knowledge Management: Maroochy Water Services
• Promotional Strategy for the New Water Based Theme Park in Darling Harbor
• Fiji Water Report
• Marketing Strategy for Bottled Water in Hong Kong
• Water Boarding as a Form of Criminal Interrogation in the US
• Scarcity of Water in Saudi Arabia, Africa and Australia
• The Ancient and the Medieval Worlds: The Use of Water Power
• Power Water Corporation (PWC): Compiling a Business Strategy
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Exploration of the synergistic regulation mechanism in cerebral ganglion and heart of eriocheir sinensis on energy metabolism and antioxidant homeostasis maintenance under alkalinity stress.

1. Introduction

2. materials and methods, 2.1. experimental crabs and alkalinity stress, 2.2. measurement of serum biochemical parameters, 2.3. proteomics analysis on cerebral ganglion of e. sinensis, 2.3.1. proteins extraction, separation, enzymolysis, and desalination, 2.3.2. lc-ms/ms analysis and database query, 2.3.3. gene ontology (go) annotation on proteomic, 2.3.4. enrichment analysis on differentially expressed proteins (deps), 2.4. metabolome analysis on heart of e. sinensis, 2.4.1. extraction of metabolites from heart of e. sinensis and uplc-ms analysis, 2.4.2. pca and partial least-squares discrimination analysis (pls-da) on differentially expressed metabolites (dems), 2.4.3. kegg enrichment analysis on dems, 2.5. combined analysis on cerebral ganglion proteomic and heart metabolome, 3.1. analysis on serum biochemical parameters of e. sinensis under alkalinity stress, 3.2. proteomic analysis on cerebral ganglion under alkalinity stress, 3.3. heart metabolomics analysis under alkalinity stress, 3.4. integrated analysis on cerebral ganglion proteomics and heart metabolomics under alkalinity stress, 4. discussion, 4.1. regulation on energy metabolism and signal transduction in cerebral ganglion and heart under acute alkalinity stress, 4.2. the co-regulation of cerebral ganglion and heart on signal transduction under alkalinity stress, 4.3. synergistic regulation on longevity and antioxidant homeostasis maintenance under alkalinity stress, 5. conclusions, author contributions, institutional review board statement, informed consent statement, data availability statement, acknowledgments, conflicts of interest.

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Wang, M.; Zhou, J.; Xu, G.; Tang, Y. Exploration of the Synergistic Regulation Mechanism in Cerebral Ganglion and Heart of Eriocheir sinensis on Energy Metabolism and Antioxidant Homeostasis Maintenance under Alkalinity Stress. Antioxidants 2024 , 13 , 986. https://doi.org/10.3390/antiox13080986

Wang M, Zhou J, Xu G, Tang Y. Exploration of the Synergistic Regulation Mechanism in Cerebral Ganglion and Heart of Eriocheir sinensis on Energy Metabolism and Antioxidant Homeostasis Maintenance under Alkalinity Stress. Antioxidants . 2024; 13(8):986. https://doi.org/10.3390/antiox13080986

Wang, Meiyao, Jun Zhou, Gangchun Xu, and Yongkai Tang. 2024. "Exploration of the Synergistic Regulation Mechanism in Cerebral Ganglion and Heart of Eriocheir sinensis on Energy Metabolism and Antioxidant Homeostasis Maintenance under Alkalinity Stress" Antioxidants 13, no. 8: 986. https://doi.org/10.3390/antiox13080986

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• Sunday 28 July 28 2024, 11:00 – 16:30 (TBC)
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The U.S. Department of Energy (DOE) today released a report that makes actionable recommendations to address five gaps in the domestic hydropower supply chain. Hydropower makes up about 27% of renewable electricity generation in the United States and is an important component of the nation’s goal of achieving a 100% clean electricity sector by 2035. A robust domestic supply chain is critical to support new construction and upgrades, refurbishments, and relicensing activities at existing hydropower facilities. The new in-depth report, titled Hydropower Supply Chain Gap Analysis , considers various sectors of the hydropower supply chain, from mining and extraction to installation and construction.

A new report from the U.S. Department of Energy makes actionable recommendations to address five gaps in the domestic hydropower supply chain.

“As more variable renewable energy sources like solar and wind are incorporated into the U.S electricity grid, hydropower will play a key role in keeping it reliable and stable,” said Jeff Marootian, Principal Deputy Assistant Secretary for Energy Efficiency and Renewable Energy. “These new recommendations will strengthen the domestic supply chain needed to enhance our nation’s hydropower capabilities.”

Drawing on feedback from hydropower industry stakeholders gathered by DOE’s Water Power Technologies Office (WPTO), researchers identified five major gaps:

• Unpredictable and variable demand signals for materials and components.  In general, hydropower systems have exceptionally long lives (e.g., 30–50 years), so replacements and refurbishment schedules have cycles that are years or decades. 
• Severely limited or nonexistent domestic suppliers for materials and components.  Only one or two—or in some cases, no—domestic suppliers exist for materials and components.
• Federal contracting procedures and domestic content laws. There are several procurement regulations and/or general practices that inhibit the development of the domestic hydropower supply chain.
• Foreign competition, foreign subsidies, and ineffective trade policies.  Discussions with companies in the hydropower industry highlighted inequitable competition from foreign companies and ineffective trade policies as issues in the hydropower supply chain.
• Shortage of skilled workers.  Hydropower manufacturing and upstream support industries suffer from a significant lack of expertise in the workforce. As these industries have been offshored over the last 40 years, skilled workers have retired or moved to other industries.  

On Thursday, Sept. 5, 2024, at 10:30 a.m. ET , U.S. Secretary of Energy Jennifer M. Granholm will join experts from WPTO, other government agencies, and the hydropower industry during a webinar about the Hydropower Supply Chain Gap Analysis . Speakers will explore the gaps facing the U.S. hydropower supply chain along with the potential remedies. Register now .

To address the gaps in the domestic hydropower supply chain, the report recommends to:

• Lead with the federal fleet to prime the development of an aggregated, consistent demand signal.  Nearly 50% of the domestic hydropower fleet is federally owned. The potential demand signal from new federal facilities and refurbishments can be significant. Federal procurement processes should be evaluated to ensure that they are effective in developing the domestic supply chain while obtaining the hydropower and pumped storage hydropower equipment and services the federal fleet needs.
• Increase awareness of the domestic supply chain through the development of databases of domestic manufacturing and installations.  Developing tools to predict demand is another way that WPTO can help both the federal and private fleets. Tools currently in development or undergoing enhancements include a database of domestic suppliers along the hydropower supply chain and a tool that allows users to see data (e.g., size, turbine type) on individual hydropower generation units.
• Work with other low-carbon technologies industries to create a significant, steady, and predictable demand signal for common materials.  While the demand from the hydropower industry is in the billions of dollars annually, it is not sufficient to build out a domestic industry, especially in the material and component sectors.   However, many of the components and materials used for hydropower systems (e.g., transformers and electrical steel) are also used in other clean energy technologies, such as wind energy, and for upgrading the electric grid. Industries such as ship manufacturing and defense supply chains also have commonalities with hydropower. These industries can be leveraged so that the aggregate demand can address gaps in their respective supply chains.
• Continue workforce development efforts.  There are few low-carbon energy technologies that have as significant of a gap in educational programs as hydropower. In addition to expanding academic programs, there are also a vast array of experiential-type programs that can help raise the awareness of hydropower and its opportunities , including internships/fellowships/apprenticeships, experiential placements, job fairs, primary and secondary school competitions, collegiate competitions , programs that place veterans and other unique workforce segments, and more.

These recommendations incorporate feedback from industry stakeholders and will guide DOE’s strategies to strengthen the domestic hydropower supply chain. With a more robust understanding of existing and required domestic hydropower manufacturing capabilities, DOE can better define the market for planned rehabilitations and new construction. These recommendations can inform policies, incentives, loan programs, and technology investments to encourage domestic content. Further, the identified gaps and recommendations can help focus DOE’s workforce development efforts in areas that will also support the domestic hydropower supply chain.

The Hydropower Supply Chain Gap Analysis builds on the Hydropower Supply Chain Deep Dive Assessment , part of a series of reports produced in response to Executive Order 14017 “America’s Supply Chains.” This executive order directed the Secretary of Energy to submit a report on supply chains for the energy sector industrial base. It also aimed to help build more secure and diverse U.S. supply chains, including energy supply chains.  

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Relative-Price Changes as Aggregate Supply Shocks Revisited: Theory and Evidence

We provide theory and evidence that relative price shocks can cause aggregate inflation and act as aggregate supply shocks. Empirically, we show that exogenous positive energy price shocks have a positive impact not only on headline but also on U.S. core inflation while depressing U.S. real activity. In a two-sector monetary model with upstream and downstream sectors and heterogeneous price stickiness, we analytically characterize how upstream shocks propagate to prices. Using panel IV local projections, we show that the responsiveness of sectoral PCE prices to energy price shocks is in line with model predictions. Motivated by post-COVID inflation in the U.S., a model experiment shows that a one-time relative price shock generates persistent movements in headline and core inflation similar to those observed in the data, even in the absence of aggregate slack. The model also emphasizes that monetary policy stance plays an important role in propagation of such shocks.

We thank Klaus Adam, Larry Ball, Larry Christiano, Ippei Fujiwara, Yuriy Gorodnichenko, Raphael Schoenle, Felipe Schwartzman, and conference and seminar participants at the NBER conference on Inflation in the COVID era and Beyond, Keio University, and Sabanci University for very helpful comments. We thank Raphael Schoenle for generously sharing data on frequency of price adjustment across U.S. sectors. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.

MARC RIS BibTeΧ

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