Surface Drinking Water Sources Research Articles

Quantitative Effects of Anthropogenic and Natural Factors on Heavy Metals Pollution and Spatial Distribution in Surface Drinking Water Sources in the Upper Huaihe River Basin in China.

The water quality of sources in the Huaihe River Basin significantly affects the lives and health of approximately 16.7% of China's population. Identifying and quantifying pollution sources and risks is essential for effective water resource management. This study utilized Monte Carlo simulations and Geodetector to assess water quality and eutrophication, as well as to evaluate the sources of heavy metals and the associated health risks for both adults and children. The results showed that eutrophication of water sources in Huaihe River was severe, with an overall EI value of 37.92; 67.8% of the water sources were classified as mesotrophic and 32.2% classified as eutrophic. Water quality and eutrophication levels in the southern mountainous regions were better than those in the densely populated northern areas. Adults were found to have a higher carcinogenic risk than children, whereas children faced a higher noncarcinogenic risk than adults. Cr presented the highest carcinogenic risk, affecting more than 99.8% of both adults and children at levels above 1 × 10-6 but not exceeding 1 × 10-4. The noncarcinogenic risk from metals did not surpass a level of 1, except for Pb. As was primarily influenced by agricultural activities and transportation, whereas Cd, Cr, and Pb were mainly affected by industrial activities, particularly in local textile industries such as knitting and clothing manufacturing. The analysis demonstrated that the influence of anthropogenic factors on heavy metal distribution was significantly enhanced by indirect natural factors. For example, the explanatory power of Precipitation and Road Network Density on As was 0.362 and 0.189, respectively, whereas their interaction had an explanatory power as high as 0.673. This study indicates that the geodetector method is effective in elucidating the factors influencing heavy metal distribution in water, thereby providing valuable insights into pollution sources in global drinking water.

Examining drinking water quality: analysis of physico-chemical properties and bacterial contamination with health implications for Shangla district, KhyberPakhtunkhwa, Pakistan.

A comprehensive understanding of water quality is essential for assessing the complex relationship between surface water and sources of pollution. Primarily, surface water pollution is linked to human and animal waste discharges. This study aimed to investigate the physico-chemical characteristics of drinking water under both dry and wet conditions, assess the extent of bacterial contamination in samples collected from various locations in District Shangla, and evaluate potential health risks associated with consuming contaminated water within local communities. For this purpose, 120 groundwater and surface water samples were randomly collected from various sources such as storage tanks, user sites, streams, ponds and rivers in the study area. The results revealed that in Bisham, lakes had the highest fecal coliform levels among seven tested sources, followed by protected wells, reservoirs, downstream sources, springs, rivers, and ditches; while in Alpuri, nearly 80% of samples from five sources contained fecal coliform bacteria. Similarly, it was observed that the turbidity level, total dissolved solids, electrical conductivity, biological oxygen demand, and dissolved oxygen in the surface drinking water sources of Bisham were significantly higher than those in the surface drinking water sources of Alpuri. Furthermore, the results showed that in the Alpuri region, 14% of the population suffers from dysentery, 27% from diarrhea, 22% from cholera, 13% from hepatitis A, and 16% and 8% from typhoid and kidney problems, respectively, while in the Bisham area, 24% of residents are affected by diarrhea, 17% by cholera and typhoid, 15% by hepatitis A, 14% by dysentery, and 13% by kidney problems. These findings underscore the urgent need for improved water quality management practices and public health interventions to mitigate the risks associated with contaminated drinking water. It is recommended to implement regular water quality monitoring programs, enhance sanitation infrastructure, and raise awareness among local communities about the importance of safe drinking water practices to safeguard public health.

Investigating the Diversity and Taxonomy of Aquatic Insects in Surface Drinking Water Sources of Pithoragarh, Uttarakhand, India

Investigating the Diversity and Taxonomy of Aquatic Insects in Surface Drinking Water Sources of Pithoragarh, Uttarakhand, India

Canada Source Watershed Polygons (Can-SWaP): A dataset for the protection of Canada’s municipal water supply

Over 80% of municipal (i.e., excluding industrial and agricultural) water use in Canada comes from streams, lakes, and reservoirs. These freshwater bodies and their catchments require adequate protection to secure drinking water supply for Canadians. Canada, like most countries, lacks a consolidated national dataset of municipal catchments, arguably due to gaps in data availability. Against this backdrop, we present the Canada Source Watershed Polygons dataset, or Can-SWaP. Can-SWaP was created using point locations of more than 3,300 municipal water licences defining rights to surface water withdrawal. Where possible, the resulting 1,574 catchments were assessed for accuracy in spatial coverage against provincial and local datasets. Each watershed in Can-SWaP has an estimated water volume used for municipal water purposes derived from licencing data, and several variables from RiverATLAS for investigating the integrity of surface drinking water sources in Canada. Furthermore, basing our method on the HydroSHEDS suite of global products offers a robust framework for the production of other national datasets following an established international standard.

Usage of Rat Fibroblasts to Assess Toxic Properties of Contaminated Water

Introduction: Changes in the composition of surface water caused by hydrological and climatic processes and anthropogenic effluents affect its properties, making it potentially hazardous to human health. Monitoring of water quality and safety does not take into account all potentially dangerous elements and their compounds the man can be exposed to, since the occurrence of new substances and recombination of existing ones is accompanied by a continuous transformation of the physicochemical composition of water, which determines its biological properties. This screening study opens new perspectives for biological testing on cell cultures as an approach to assessing water safety. Objective: To examine the method of bioassay of general indicators of water using rat fibroblasts and a regression model. Materials and methods: We tested physicochemical parameters of water of a surface drinking water source sampled in fall 2020 and winter–summer 2021 and assessed its safety on rat fibroblast cells using the MTT assay. We then built a regression model of the cellular response based on 20 indicators, with the choice of the most significant predictors. Results: We revealed seasonal fluctuations in the physicochemical composition of surface water with no toxicity limits exceeded. The lowest values of dehydrogenase activity of the fibroblast cell culture were revealed following the exposure to water sampled in autumn while that taken in summer had the most favorable effect on cell viability. Conclusions: We revealed changes in physicochemical indicators characterizing quality and safety of source water in different seasons. Testing of the method of water bioassay (MTT assay) on the culture of rat fibroblast cells showed sensitivity in relation to general indicators of water quality. Based on mathematical modeling, we established that dissolved iron, which can serve as an indicator of changes in metabolic processes, is a parameter that reliably characterizes toxic effects on the fibroblast cell culture.

Spatial correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in a typical coal-fired pollution fluorosis area

Objective: To investigate the spatial distribution characteristics and correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in coal-fired fluorosis areas. Methods: Based on the survey data on the prevalence of dental fluorosis at CDC in Guizhou Province in 2022, 274 original surface drinking water sources were collected in typical coal-fired fluorosis areas, and fluoride (F), calcium (Ca), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), barium (Ba), lead (Pb) 17 elements; apply Moran's I index, Getis-Ord Gi* hotspot analysis of the global spatial autocorrelation of chemical elements in drinking water and the degree of aggregation of each element on the local area, and correlation analysis with the prevalence of dental fluorosis in the region. Results: Except for Cu, Zn, and Cd, global spatial autocorrelation Moran's I was negative, and all other elements were positive. F, Ca, Al, Ti, As, Mo, Cd, and Cu elements showed high values of aggregation in the southeastern low-altitude area; Mg, Ba, Pb, Cr, Mn, and Fe elements were mainly aggregated in the central altitude terrain transition area, Zn and Se elements in water sources are significantly positively correlated with the prevalence of dental fluorosis (P<0.05). In contrast, F, Mg, Al, Ti, As, Mo, Cd, Ba, and Pb elements negatively correlate (P<0.05). Elements in the central region were high-high aggregation, as a hot spot aggregation area with high disease incidence, while F, Al, Mn, Mo, Cd, and Ba elements in the western region were low-low aggregation, as a cold spot aggregation area with a low incidence of fluorosis. Conclusions: The risk of population fluoride exposure in surface drinking water sources is shallow. However, the chemical element content of drinking water sources in coal-fired polluted endemic fluorosis areas has prominent spatial geographical distribution characteristics. There is a significant spatial aggregation effect with the prevalence of dental fluorosis, which may play a synergistic or antagonistic effect on the occurrence and prevalence of dental fluorosis.

Composition Structure and Influence Factors of Bacterial Communities in the Miyun Reservoir

As the largest reservoir in North China, the Miyun Reservoir is the most important surface drinking water source in Beijing. Bacteria are key regulators of reservoir ecosystem structure and function, and exploring the community distribution characteristics of bacteria is important for maintaining water quality safety in reservoirs. The spatiotemporal distribution and environmental factors of bacterial communities in the water and sediment of the Miyun Reservoir were explored using the high-throughput sequencing method. The results showed a higher α-diversity and non-significant seasonal variation of the bacterial community in the sediment, and the abundant sedimental species were affiliated with Proteobacteria. For planktonic bacteria, Actinobacteriota was the dominant phylum, and the seasonal variance was represented by CL500-29_marine_group and hgcI_clade in the wet season and Cyanobium_PCC-6307 in the dry season. Additionally, obvious differences in key species were also found in water and sediment, and more indicator species were obtained in sedimental bacteria. Further, a more complex co-existence network was identified in water compared to that in sediment, indicating the strong ability of planktonic bacteria to resist environmental changes. Environmental factors had a significantly higher effect on the bacterial community of the water column than that of the sediment. Furthermore, SO2-4 and TN were the main factors affecting planktonic bacteria and sedimental bacteria, respectively. These findings revealed the distribution patterns and driving forces of the bacterial community in the Miyun Reservoir, which will provide important guidance for reservoir management and water-quality assurance.

Biotesting for the objectivization of the hygienic evaluation of the surface and underground drinking water sources

Introduction. An algorithm for evaluating the hygienic safety of drinking water sources based on biotesting and studying sanitary and chemical indicators has been developed and tested. Materials and methods. The research methods included sanitary and chemical analysis of water samples, as well as biotesting methods using single-celled green alga Chlorella vulgaris Beijer and bull spermatozoa. Results. For experimental approbation of the developed algorithm for determining the hygienic safety of water based on a two-component system of express biotesting and measurement of sanitary and chemical indicators, 6 underground and 5 surface water sources were evaluated. The response of test objects indicating the presence of acute toxicity in water samples taken from surface and underground in many cases correlates with the excess of MPC for individual indicators identified by sanitary and chemical analysis. For two water samples, differences were found between the results of biotesting and sanitary-chemical analysis, and therefore it is necessary to conduct an extended toxicological and chemical assessment to identify the source of toxic effects. Limitations. The two-component test system cannot be used separately without sanitary and chemical analysis of water media. Conclusion. Biotesting can be an addition to sanitary and chemical analyses, showing the presence of toxic substances that are not in the list of mandatory indicators to be determined (according to MR 2.1.4.0176-20 (in Russian)).

AWWA Water Science Author Spotlight

<i>AWWA Water Science</i> Author Spotlight

Enhanced electrocoagulation process for natural organic matter removal from surface drinking water sources: coagulant dose control &amp; organic matter characteristics

An optimized electrocoagulation process was investigated for enhanced removal of dissolved organic matter for eco-friendly drinking water production from surface water sources. A model-based control system was developed for electro-coagulant dosing.

Strategic reserves in Oregon’s forests for biodiversity, water, and carbon to mitigate and adapt to climate change

Creating strategic forest reserves is essential for stemming the loss of biodiversity and contributing to climate mitigation and adaptation. Meeting preservation targets of 30% protection by 2030, and 50% by 2050 would lead to greater protection of animal taxa and tree species habitat, carbon stocks and accumulation, and forests that are important sources of drinking water. Here, we develop a regional framework to specifically identify at a fine resolution (30 m) high priority forestlands for preservation in Oregon, USA. We include a resilience metric that represents connectivity and topographic diversity, and identify areas within each ecoregion that are ranked high priority for carbon, biodiversity, resilience and drinking water. Oregon has less than 10% of its forestlands protected at the highest levels, yet its temperate forests are among those with the highest carbon densities in the world. Reserves for surface drinking water sources and forest habitat for birds, mammals, amphibians, and reptiles could increase to 50–70% protection at the highest levels by 2050. Protected aboveground biomass carbon could triple to 635 teragrams of carbon by 2050. The ownership of the high preservation priority lands for carbon and biodiversity is primarily federal (67% by 2050) followed by private (28% by 2050), with much less in the other ownerships. Forest reserves could be established on federal lands through executive action, regulation and rule-making, while private landowners could be incentivized to store more carbon, limit harvest in certain areas and transfer ownership to land trusts. Protecting mature and old forests on federal lands fulfills an urgent need for protection and provides a low-cost way to simultaneously meet national and international goals. This study provides a flexible, dynamic framework for identifying areas that are high priority to protect for climate mitigation and adaptation at regional and sub-regional scales.

Hydrological and water quality simulation and future runoff prediction under CMIP6 scenario in the upstream basin of Miyun Reservoir

AbstractWater resources are a key factor restricting human survival and social and economic development. The Miyun Reservoir, which is the only surface drinking water source in Beijing and the water storage reservoir of the South-to-North Water Diversion Project, plays a decisive role in ensuring water-use sustainability of the capital. This study focused on the Baihe River Basin, which is one of the important inflows of the Miyun Reservoir. The mathematical data on the climate and hydrological changes of the Baihe River Basin over the past 30 years were obtained, and the evolution law of the Baihe River runoff and its influencing factors was analyzed. Our analysis used the data obtained via multi-source meteorology to establish the Soil and Water Assessment Tool (SWAT) model of the Baihe River Basin. Sequential Uncertainty Fitting version 2 (SUFI-2) and Generalized Likelihood Uncertainty Estimation (GLUE) were used to simulate runoff from 1990 to 2017 on a monthly scale, along with sediment, total nitrogen (TN), and total phosphorus (TP) contents from 1990 to 2010. Then, the parameter uncertainty of the SWAT model and the applicability of the SWAT model in the Baihe River Basin were determined. The land-use transfer matrix showed that land-use changes are complex and the transformation forms are diverse. The simulation results showed that the transformation of land-use patterns in 1990 and 2010 had slight impacts on the hydrologic and water quality of the basin. By identifying the key source areas of non-point source pollution in the basin, the impacts of three management measures on the hydrological and water quality of the basin were simulated. The results showed that the reductions in flow rates, sediment content, TN, and TP (4.37, 31.93, 23.13, and 35.30%, respectively) obtained through terrace engineering were significantly better than those acquired via stubble mulch and contour planting. Additionally, this study uses the Sixth International Coupling Mode Comparison Program (CMIP6) climate change scenario and the BCC-CSM2-MR climate model coupled with the corrected SWAT model to predict future runoff, thereby providing references and suggestions for managing the Baihe River Basin and the Miyun Reservoir.

Pollution Characteristics and Risks of Polycyclic Aromatic Hydrocarbons in Underground and Surface Drinking Water Sources in Northeast Inner Mongolia

Polycyclic aromatic hydrocarbons (PAHs) are hazardous and ubiquitous pollutants in the aquatic environment, and understanding the pollution characteristics and risk levels of PAHs is of great significance to the sustainable development of drinking water sources and drinking water safety. Hence, PAHs residues were measured qualitatively and quantitatively with solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) in 33 water samples (including 22 groundwater and 11 surface water samples) of the drinking water sources in the Manzhouli and Xinyouqi areas of northeast Inner Mongolia, and assessments of the pollution level of PAHs and the health and ecological risks were carried out. The results showed that PAHs were detected in all 33 sampling points of Manzhouli drinking water sources, except for benzo[k] fluoranthene, benzo[a] pyrene, and dibenzo[a,h] anthracene, with detection rates ranging from 36.36% to 95.45%; the detection rates of the other 13 PAHs monomers were 100%. The detection range of ρ（ΣPAHs） was 42.76-164.50 ng·L-1, and the mean value was 90.82 ng·L-1. The detection ranges of ρ（ΣPAHs） in surface water and groundwater were 66.39-164.50 ng·L-1 and 42.76-147.70 ng·L-1, respectively. The concentration of the detected naphthalene was the highest, with a mean value of 36.91 ng·L-1, and the concentration of anthracene was the lowest, with a mean value of 0.81 ng·L-1; there were no significant differences among the concentrations of all the PAHs monomers of the surface and groundwater (P>0.05). The pollution of PAHs was at a median level in China and abroad, mainly in the middle and low loops (3-4 loops). The analysis of the sources of PAHs in groundwater and surface water in Manzhouli using the ratio feature method and principal component analysis showed that the PAHs in the drinking water source water bodies in the Manzhouli area were mainly affected by the combustion of coal and biomass and oil, and some surface water sources were affected by the oil source. The human health and ecological risk assessment results showed that the water body of drinking water would not cause health risks to the human body, and the ecological risk was at a medium level; however, the high risk of benzo[b] fluoranthene (BbF) monomer production should be continuous cause for concern. From the perspective of the sustainable development of drinking water sources and drinking water safety, the necessary supervision and protection measures should be considered to prevent further pollution. The results of this research provide a scientific basis for the pollution control and prevention and control of PAHs in drinking water sources.

Drinking Water Quality Assessment of Metro Bus Stations of Islamabad and Rawalpindi

Water is the most wonderful substance. Almost 70% of our planet consists of water. The human body comprises almost 60% of water. Safe and clean water is necessary for all purposes in daily life which include different practices like washing, drinking, cooking, and personal cleanliness (Frances and Brack, 2018). Water is known as a universal solvent because it can dissolve a large proportion of natural or man-made substances (Balasubramanian, 2015). Fecal contaminated water is the main reason for waterborne disease. With quick urbanization, the chemical feature of water quality has contributed to increasing concerns as toxic chemicals industrial effluents pose a high hazard to life (Alurralde et al., 1998). Pakistan has been blessed with water resources, but unfortunately over the years, industrial development, overpopulation, and rapid growth have decelerated the water resources (Daud et al., 2017). Different studies show that the majority of the supplies of potable water are polluted (Aziz, 2005). Pakistan ranks 80 out of 122 nations, and both ground and surface drinking water sources are polluted throughout the country with toxic metals, microbes, and pesticides (Nabeela et al., 2014). Even currently some rural areas in Pakistan have no availability of fresh and clean water for regular use (Shahid et al., 2014). The quality of drinking water in Pakistan is reducing day by day due to the waste and pollutants released by the industries. Channeled water also gets contaminated because the network of the pipeline is not planned and laid poorly (Imran et al., 2018).

Application of nanoparticles for the removal of heavy metals from wastewater

Heavy metals along with diverse chemicals, released from different anthropogenic sources are alarmingly contaminating drinking water which has become a global concern. Quality of drinking water in Pakistan is overlooked, poorly monitored and managed both surface and groundwater drinking water sources are being contaminated. This drinking water being polluted is relatively a new problem directly related to unprecedented growth in population, urbanization, and industrialization in recent years as a result stress is arising. Human health and environment face major consequences due to this contamination of water resources. To combat these problems and to meet the basic human right of safe drinking water, novel water treatment technologies are emerging. Developing sustainable methods for water treatment is a major concern. Nanotechnology is one of its kind in this perspective. This technology has immense potential to restore polluted water efficiently and effectively. The present study’s aim was to determine the potential of Green synthesized iron oxide nanoparticles for the removal of heavy metals from wastewater

Contrasting patterns of 2-methylisoborneol (MIB) vs. geosmin across depth in a drinking water reservoir are mediated by cyanobacteria and actinobacteria

Taste and odor episodes caused by off-flavor secondary metabolites, such as 2-methylisoborneol (MIB) and geosmin, pose one of the greatestchallenges for drinking water utilities around the world. The prevalence of these compounds is predicted to increase in the future as a function of nutrient enrichment and elevated temperatures of surface drinking water sources. We conducted a manipulative field experiment in a drinking water reservoir to elucidate patterns for two taste and odor compounds, MIB and geosmin, as well as two taxa known to produce these compounds, phytoplankton (more specifically, cyanobacteria) and actinobacteria, across different depths in response to nutrient enrichment with two common dissolved nitrogen forms, organic urea or inorganic nitrate. In general, we found that MIB levels increased by greater than 250% with nutrient enrichment mediated by increased phytoplankton biomass. However, the effect of the fertilization treatments on MIB decreased with depth with a 35% reduction at 7m versus 1.5 m. In contrast, geosmin levels reached a maximum at the lowest measured depth (7 m), were unaffected by the fertilization treatments, and followed a similar pattern to the abundance of actinobacteria. Thus, our data suggest that the positive response of phytoplankton (e.g., cyanobacteria, such as Oscillatoria species) to the fertilization treatments is likely responsible for increased MIB, while geosmin concentrations may be a function of actinobacteria-mediated decomposition in the hypolimnion in our study system.

Mitigating Source Water Risks with Improved Wildfire Containment

In many fire-prone watersheds, wildfire threatens surface drinking water sources with eroded contaminants. We evaluated the potential to mitigate the risk of degraded water quality by limiting fire sizes and contaminant loads with a containment network of manager-developed Potential fire Operational Delineations (PODs) using wildfire risk transmission methods to partition the effects of stochastically simulated wildfires to within and out of POD burning. We assessed water impacts with two metrics—total sediment load and frequency of exceeding turbidity limits for treatment—using a linked fire-erosion-sediment transport model. We found that improved fire containment could reduce wildfire risk to the water source by 13.0 to 55.3% depending on impact measure and post-fire rainfall. Containment based on PODs had greater potential in our study system to reduce total sediment load than it did to avoid degraded water quality. After containment, most turbidity exceedances originated from less than 20% of the PODs, suggesting strategic investments to further compartmentalize these areas could improve the effectiveness of the containment network. Similarly, risk transmission varied across the POD boundaries, indicating that efforts to increase containment probability with fuels reduction would have a disproportionate effect if prioritized along high transmission boundaries.

Occurrence and removal of dissolved metals in surface drinking water sources from Yangtze River Delta Region, East China

Occurrence and removal of dissolved metals in surface drinking water sources from Yangtze River Delta Region, East China

Microbiological evaluation and antimicrobial resistant pattern of bacteria isolated from surface drinking water sources in Ogbomoso, Oyo State, Nigeria

Water is vital for life, but in contrast, it might serves as the commonest route of transmission for many infectious diseases. This study was carried out to examine the quality of drinking water from two selected surface water within Ogbomoso. Water samples were collected from both water bodies at different points. Most Probable Number (MPN) techniques and pour plate method were used to estimate the bacteriological quality of water samples. The antibiotic sensitivity test was carried out on the isolated organisms, while heavy metals parameters were assessed with standard methods. Water samples were analyzed for faecal sterols. Results of MPN counts (49 to 1600 MPN per 100ml) and total heterotrophic counts (0.15×10 6 to 1.36×10 7 CFU/mL) revealed a high level of microbial pollution. Ten genera of bacteria; Shigella , Corynebacterium , Streptococcus , Pseudomonas , Staphylococcus , Escherichia , Salmonella , Vibrio , Citrobacter and Klebsiella were isolated and they all showed multiple antibiotic resistant (MAR) to all the antibiotics used. The multiple antibiotics resistant (MAR) index ranged from 0.63 to 0.75 and 0.63 to 0.88 for the isolates from Papa –Osiagoro and Oke- Baaki water works respectively. The heavy metals analyzed fell within the limits set by Nigerian Standards for potable waters with exception of Zn which had high concentrations across the sampling points. Water samples showed the presence of high concentrations of feacal sterols. The presence of coliforms and other pathogenic organisms present in these surface water bodies have shown that they are highly contaminated. Thus, the water is not fit for human consumption due to feacal contamination. Keywords: Ogbomoso, Microbial pollution, Antibiotic resistance, Heavy metals, feacal sterols

THE EPIDEMIOLOGICAL ANALYSIS OF GROUP MORBIDITY OF ACUTE INTESTINAL INFECTIONS OF WATER ETIOLOGYON THE TERRITORY OF THE ARKHANGELSK REGION

The analysis of group morbidity of acute intestinal infections of water etiology was implemented in the Arkhangelsk region in 2000-2016. During the mentioned period, 183 ictuses were registered and 22 out of them (12%) had water way of transfer with 796 individuals as a total number of victims and 498 out them were children aged from 0 to 17 years. The ictus morbidity of acute intestinal infections realizing through water way, is characterized by high intensity of epidemiological process. The index of nidality made up to 36 victims per 1 water ictus. The cities and regions of occurrence of niduses (Arkhangelsk, Novodvinsk, Primorskiy, Plesetskiy and Holmogorskiy districts) relate to territories with surface drinking water source (Severnaya Dvina river). In etiological structure of water ictuses prevail cases of ictus morbidity of dysentery (63.7%), rotavirus infection (22.7%), ictuses of enterovirus infection (13.6%) and opportunistic flora (13.6%).