Integrated water risk early warning framework of the semi-arid transitional zone based on the water environmental carrying capacity (WECC)

Water risk early warning systems based on the water environmental carrying capacity(WECC)are powerful and effective tools to guarantee the sustainability of rivers.Existing work on the early warning of WECC has mainly concerned the comprehensive evaluation of the status quo and lacked a quantitative prejudgement and warning of future overload.In addition,existing quantitative methods for short-term early warning have rarely focused on the integrated change trends of the early warning indicators.Given the periodicity of the socioeconomic system,however,the water environmental system also follows a trend of cyclical fluctuations.Thus,it is meaningful to monitor and use this periodicity for the early warning of the WECC.In this study,we first adopted and improved the prosperity index method to develop an integrated water risk early warning framework.We also constructed a forecast model to qualitatively and quantitatively prejudge and warn about the development trends of the water environmental system.We selected the North Canal Basin(an essential connection among the Beijing-Tianjin-Hebei region)in China as a case study and predicted the WECC in 25 water environmental management units of the basin in 2018–2023.We found that the analysis of the prosperity index was helpful in predicting the WECC,to some extent.The result demonstrated that the early warning system provided reliable prediction(root mean square error of 0.0651 and mean absolute error of 0.1418),and the calculation results of the comprehensive early warning index(CEWI)conformed to the actual situation and related research in the river basin.From 2008 to 2023,the WECC of most water environmental management units in the basin had improved but with some spatial differences:the CEWI was generally poor in areas with many human disturbances,while it was relatively good in the upstream regions with higher forest and grass covers as well as in the downstream areas with larger water volume.Finally,through a sensitivity analysis of the indicators,we proposed specific management measures for the sustainability of the water environmental system in the North Canal Basin.Overall,the integrated water risk early warning framework could provide an appropriate method for the water environmental administration department to predict the WECC of the basin in the future.This framework could also assist in implementing corresponding management measures in advance,especially for the performance evaluation and the arrangement of key short-term tasks in the River Chief System in China.

Gross Alpha and Beta Activities and Related Lifetime Risks Assessment Due to Ingestion of Drinking Water from Different Sources in the District of Abidjan, Cote d’Ivoire

Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMaticTM) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.

Risk-based water quality decision-making under small data using Bayesian network

A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal transformation of variables with routine monitoring data and normal assumption of variables without routine monitoring data,a conditional linear Gaussian Bayesian network is constructed.A "two-constraint selection" procedure is proposed to estimate potential parameter values under small data.Among all potential parameter values,the ones that are most probable are selected as the "representatives".Finally,the risks of pollutant concentration exceeding national water quality standards are calculated and pollution reduction decisions for decision-making reference are proposed.The final results show that conditional linear Gaussian Bayesian network and "two-constraint selection" procedure are very useful in evaluating risks when there is limited data and can help managers to make sound decisions under small data.

Health Risk Assessment on Rural Drinking Water Safety —A Case Study in Rain City District of Ya’an City of Sichuan Province

Taking Rain City District of Ya’an for example, this paper based on ComGIS (Component Object Model Geographic Information System) platform takes comprehensive and systematic detection on the exposure dose of chemical carcinogens and non-carcinogens from drinking water sources in this region and discusses health risk assessment of single factor and the whole health risk assessment. As, Hg, Cr, Pb, Cd and fluorides in some drinking water sources of Rain City District are analyzed according to Standards For Drinking Wa-ter Quality (GB5749-2006). A health risk assessment model called USEPA is also applied to drinking water health risk assessment and management countermeasure is proposed. The results show that the greatest health risk for individual person per year is caused by Cr(VI). The health risk of carcinogens is much higher than that of non-carcinogens: the greatest risk value due to non-carcinogen pollutants is caused by fluoride (F), achieving 1.05×10-8/a. The ranking of risk values due to non-carcinogen pollutants by drinking water is Pb>fluoride (F)>Hg, within Pb accounting for 44.77%, fluo-ride (F) accounting for 34.30% and Hg accounting for 20.92%. The average individual carcinogenesis annual risk of Cr(VI) is the greatest, achieving 8.91×10-4/a. The ranking of risk value due to chemical carcinogen by rural drinking water of Ya’an is Cr6+>As>Cd, within Cr6+ accounting for 91.12%, As accounting for 5.89% and Cd accounting for 3.00%. Based on this, the strategy and measures of the health risk management are put forward. This study has worked efficiently in practice. Compared with the same kind of methods which have been found, the paper has the outstanding results for the health risk assessment of the rural drinking water safety.

Cumulative Risk Assessment Framework for Waterborne Contaminants

A framework is developed and applied for semi-quantitative estimation of cumulative risk from complex mixtures of compounds in water supplies. The framework places these risks onto the unifying metric of Disability Adjusted Life Years (DALYs), and harmonizes cancer and non-cancer, morbidity and mortality, effects. The framework can be used to: 1) calculate a measure of cumulative risk for a given supply, and compare this measure across supplies or across the same supply with candidate treatments applied;2) identify those compounds contributing most significantly to cumulative risk, so risk management measures can be applied most effectively;and 3) quantify the influence of different regulatory limits, for specific compounds, on the cumulative risk from drinking water. Results of application to a hypothetical water supply in which all compounds are at their existing Maximum Contaminant Level (MCL) show the cumulative risk for even a complex mixture may be dominated by a few compounds. In this application, that risk was dominated by as few as 10% of the compounds. The analysis also shows that establishing MCLs based on compounds for which there is an oral slope factor, but where no cancer-based limit has yet been established, probably will have little influence on the relative cumulative risk (as measured by Total Weighted DALY) of different water supplies. This arises primarily because the non-cancer-based MCL is usually more restrictive than the one based on cancer for target probabilities of cancer equal to 1E–4 or 1E–5.

Cancer risk assessment from exposure to trihalomethanes in tap water and swimming pool water

We investigated the concentration of trihalomethanes （THMs） in tap water and swimming pool water in the area of the Nakhon Path- om Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 μg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 μg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization （WHO）, European Union （EU） and the United States Environmental Protection Agency （USEPA） phase Ⅰ, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase Ⅱ. From the two cases of cancer risk assessment including Case Ⅰ Non-Swimmer and Case Ⅱ Swimmer, assessment of cancer risk of nonswimmers from exposure to THMs at the highest and the average concentrations was 4.43×10^-5 and 2.19×10^-5, respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47×10^-3 and 7.99×10^-4, respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was： skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.

Spatial variation of health risk of groundwater for drinking water supply in Mingshan County,Ya'an City,China

Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency （U.S. EPA）. Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation （IDW） and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6＋, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.

The Monte Carlo-Based Uncertainty Health Risk Assessment Associated with Rural Drinking Water Quality

In this study, Triangular Fuzzy-number of the Fuzzy Set Theory was introduced to reform parameters of those previous health risk assessment (HRA) models, Monte Carlo simulation parameter was applied to lower the randomness and fuzziness of the HRA system, and the Monte Carlo-United States Environmental Protection Agency (MC-EPA) model was employed to evaluate the health risk associated with water quality (HRWQ), so as to solve the uncertainty HRA associated with rural drinking water quality. Results showed that the water in Mingshan was contaminated mainly by Cr(VI), nitrate, fluoride and Fe. The health risk primarily embodied in the carcinogenic risk (CR) caused by Cr(VI) that generally exceeds the limit while little non-carcinogenic toxic effected presents. However, non-carcinogenic risk (NCR) in some water resources was high, exceeding the limit “1”. The results revealed the health risk level of the water quality and the health risk degree caused by the pollutants, providing scientific support for the management of the HRWQ of the WR. It also indicated the significance of MC-EPA model’s application.

Classification and Health Risk Assessment for Borehole Water Contaminated by Metals in Selected Households in Southwest Nigeria

Samples of borehole water were randomly collected from twenty households in the Lagos-Ogun axis of southwestern Nigeria. The samples were analyzed for silver, iron, manganese, lead, nickel, magnesium, cadmium, zinc, sodium, potassium, pH, turbidity, dissolved oxygen, electrical conductivity, alkalinity, total hardness, chloride, nitrate and sulphate following standard methods of water analysis. Results obtained were compared with global background values and WHO guidelines for drinking water. The pH values ranged from 4.17 ± 0.26 to 6.07 ± 0.27 while the metal pollution indexes are between 0.01 and 0.11. Cadmium, manganese, iron and nitrate (mg/L) levels were found to be relatively high in most of the water samples. Results obtained were analyzed statistically. Health risk assessment for exposure to cancer and non-cancer indices was evaluated. Kempster and co-workers classification of drinking water quality was applied;nineteen of the twenty household water samples were found to fall short of the ideal water quality suitable for lifetime use.

Chemical behavior and risk assessment of four pesticidesin soil and water

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ArcGIS-Based Rural Drinking Water Quality Health Risk Assessment

Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of the car-cinogen and the non-carcinogen. Based on the analysis of water environment characteristics and the identifi-cation of water environment health risk source of Sichuan Ya’an City, which includes seven counties and a district and is the typical region of the western margin of Sichuan Basin, this study calculated and analyzed the carcinogenic risk (R) and non-carcinogenic risk (hazard index, HI) by applying the health risk model recommended by the US National Research Council of National Academy of Science. Then, taking advan-tage of the geo-statistic spatial analysis function of ArcGIS, this study analyzed the assessment result data (R and HI), selected the proper interpolation approach and educed R and HI spatial distribution maps of the study area. R and HI of the single factor and integrate factors were evaluated and thus obtained the following conclusions: For one thing, the cancerous risk indexes of the vast majority of water sources (about 94%) is the level of 10-7 and it belong to the safety extension. The main carcinogen in the water sources are As, Cr6+ and Pb, their concentrations are in the ranges of 0.004-0.01, 0.005, 0.01mg/l respectively and such water source mainly distributed in Yucheng district and Mingshan county. For another, the non-cancerous hazard indexes of the vast majority of water sources (about 98%) is also less than the limit value 1 and will not harm the local residents. The health risk of non-carcinogen comes mainly from As and fluoride, their concentra-tions are in the ranges of 0.004-0.01 and 0.1-4.2mg/l respectively. The results of the integrate factors health risk assessment showed that the total cancerous risk were still at the level of 10-6, only 12 drinking water source investigation sites (5%) exceeded the drinking water management standard value of EPA (the limit value is 10-6);the total non-cancerous hazard indexes are still in the range of 10-2-10-1, and will not harm the local residents either, only 18 drinking water source investigation sites (8%) exceeded the drinking water management standard value of EPA(the limit value is 1).The densely populated areas such as Yucheng Dis-trict, Tianquan County, Yingjing County and Shimian County are where the four contaminating materials, i.e., As, Cr6+, Pb and fluoride should be monitored with emphasis. Study results disclosed the health risk control indexes of source water quality of the studied area and thus provided the scientific basis for the water quality control of water sources. This study had worked efficiently in practice. Compared with the same kind of methods which had been found, the paper had the outstanding results for the health risk assessment of the rural drinking water safety.

Health Risk Assessment of Trace Metals in Drinking Water Consumed in Dakar, Senegal

Water contamination by chemical pollutants is increasingly associated with waterborne diseases worldwide. The objective of this study is to assess the chemical health risk associated with drinking water consumption in Dakar, Senegal. The methodology adopted in this study is based on the determination of trace metals (Cd, Pb, Fe, Cu and Mn) in human drinking water by flame atomic absorption spectrometry, the estimation of the exposure of populations of the study area on the basis of the quantity of water consumed daily and the determination of the hazard quotient which allows estimating the health risk. The results indicate unacceptable levels of Pb and Cd in the water according to World Health Organization (WHO) guidelines, while the concentrations of Fe, Cu and Mn are below the regulatory values. The hazard quotient (HQ) is in the majority of samples higher than 1 in children and infants for scenario 1 (based on WHO data), reflecting a high risk for this target. In scenario 2 based on consumption data from the populations studied, the HQ is greater than 1 only in heavy consumers. The drinking water consumed by Dakar population presents health risks related to Pb and Cd, particularly for infants, children and heavy consumers, hence the need to strengthen the water treatment system before home consumption.

Effect of various drinking water on human micronucleus frequency in high-risk population of PHC

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Risk assessment of water security in Haihe River Basin during drought periods based on D-S evidence theory

The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.

Health Risk Assessment after Exposure to Aluminium in Drinking Water between Two Different Villages

A cross-sectional study was conducted at Mukim Parit Lubok (MPL) and Parit Raja (PR), Batu Pahat, Malaysia. The main objective of this study was to determine the aluminium concentration in drinking water and to perform health risk assessment prediction among respondents from these two residential areas. A total of 100 respondents were selected from the study areas based on inclusive and exclusive criteria. Two duplicates of treated water samples were taken from each respondent’s house using 200mL high-density polyethylene (HDPE) bottles and 0.4 mL (69%) pure concentrated nitric acid were added as a preservative. Aluminium concentrations were analyzed using a Lambda 25 UV/V spectrophotometer. The result showed that aluminium concentration in drinking water from MPL was 0.18 ± 0.022 mg/L and 0.22 ± 0.044 mg/L for PR. Statistical analysis showed that 14 (28%) water samples collected from MPL and 35 (70%) from PR recorded concentration of aluminium above the standard limit set by the Ministry of Health, Malaysia for drinking water guideline (0.2 mg/L). The mean value of Chronic Daily Intake (CDI) of aluminium in drinking water from PR (0.00707 mg/kg/day) was significantly higher compared to MPL (0.00164 mg/kg/day). Hazard Index (HI) calculation showed that all respondents had “HI” of less than 1. In conclusion, there was an unlikely potential for adverse health effects from aluminium intake in drinking water from both study areas. However, it was necessary for some actions to be taken in order to reduce aluminium levels found in drinking water for both locations.

Health Risk Assessment of Centralized Drinking Water Sources in Small Towns of Chongqi City: A Case Study of Beibei District

Based on the health risk assessment model of water quality recommended by United States Environmental Protection Agency (USEPA), the health risk of five centralized drinking water sources in small towns of Beibei District, Chongqing City was evaluated. The results showed that the risk of health hazard of chemical carcinogen arsenic did not exceed the acceptable level recommended by the International Commission on Radiological Protection (ICRP)(5.0×10 -5 a -1 ), but was still at the same order of magnitude as the recommended value of ICRP. The risk of the highest health hazard was 127 times higher than the maximum acceptable level recommended by Sweden EPA and Holland EPA (1.0×10 -6 a -1 ). The health risk of As in genetic toxic substances at monitoring points A, B, and C accounted for 99.99% of the total risk, showing that As was the main pollutant that posed the health risk, so priority should be given to the prevention and control of As pollution in the centralized drinking water sources in Chongqing towns.

Spatial Risk Analysis of Water Borne Diseases (Bovine Leptospirosis) in the Rive Nile State-Sudan

Geographical Information Science (GIS) technologies have been used increasingly for ecology and epidemiology of water-borne diseases, providing approach for animal health issues. This study was set up to investigate the geographical distribution of Bovine that was affected by Leptospira hardijo, in River Nile state, on October 2012. Locations of targeted cattle were delimited using GPS. Fifty three (53) of blood samples were collected, and screened in the laboratory for Leptospira hardijo specific antibodies using indirect ELISA. 15.09% had evidence of infection as determined by the presence of anti-leptospira antibodies. It was inferred that no incidences were recorded in 45 locations out of the 53 selected locations in the state. Leptospirosis risk area for transmission was mapped using 5 km buffer distance. Animals’ movements routes were mapped with their contacts area and positive samples locations, hafair locations where animals contacts were mapped. This study demonstrated the value of GIS and GPS in disease mapping for animals’ health, and this might help veterinary authorities to implement strategic interventions for animal disease control.

Risk Assessment from Catchment to Consumers as Framed in Water Safety Plans: A Study from Maiduguri Water Treatment Plant, North East Nigeria

Water safety plan as conceived by WHO can lead to prevention of pollution in each component of water supply chain which leads to ensuring safe drinking water. Risk assessment is one of the key components during the development of water safety plan, achieved by identifying hazardous events and estimating their risk towards implementing control measures. This study reports the risk assessment from catchment to consumers in Maiduguri water treatment plant in Northeast Nigeria. Tools such as the field visits, key informant interviews, questionnaire and water quality monitoring were used to identify the hazards and estimate their risk using semi-quantitative matrix. With the existing control measures, the study showed a total of 33 hazardous events;5 in catchment, 16 in treatment plant, 6 in distribution system and 6 at consumers’ points. The risk score indicated 6 are of medium risk and 9 of high risk. Catchment activities, upgrade of treatment facilities and lack of routine maintenance in the treatment plant, pipeline damages in distribution lines, and consumers’ lack of hygiene knowledge and awareness were found to be the major contributory factors which affect the desired quality. Therefore participation and commitment by all relevant stakeholders are fundamental requisite to manage the identified health risks.

Metagenomic Shotgun Sequencing Provides Prevalence Data for Pathogens, and Source-Tracking Indices Useful in Public Health Risk Assessment of Environmental Waters

State-approved membrane filtration (MF) techniques for water quality assessments were contrasted with metagenomic shotgun sequencing (MSS) protocols to evaluate their efficacy in providing precise health-risk indices for surface waters. Samples from a freshwater receiving pond (ABI-1002) and two upstream storm water ditches (ABI-1003) and (ABI-1004) yielded alarmingly high Fecal coliform MF densities of 220, >2000 and >2000 CFU/100ml respectively. The indicator, Enterococcus bacteria exceeded allowable limits in all but the equipment control (ABI-1001). Using MSS, the relative numerical abundance of pathogenic bacteria, virulence and antibiotic resistance genes revealed the status and potential pollution sources of each ditch. High levels of Shigella sp. (0 (ABI-1001), 4945 (ABI-1002), 55,008 (ABI-1003), and 2221 (ABI-1004) genomic reads/100ml) correlated with virulence genes and antibiotic resistance genes found in fecal samples for ABI1003 and not ABI1004. Traditional culture methods (TCM) showed possible fecal contamination in two of the four samples, and no contamination in the others. MSS clearly distinguished between fecal and environmental bacteria contamination sources, and pinpointed actual risks from pathogens. Our data underscore the potential utility of MSS in precision risk assessment for public and biodiversity health and tracking of environmental microbiomes shifts by field managers and policy makers.

Environmental risk assessment of the middle route of south－to－north water transferring source project in China

This paper focused on the environment risk of the middle route of south-to-north water transferring source project in China. Analytic hierarchy process was applied to risk identification,fuzzy probability-fault tree analysis to risk probability assessment,statistics and analogy process to risk consequences assessment, lastly, grey relevant analysis and comprehensive index process to risk impact evaluation. The main environment risk accident of the project is dam failure, the main causative factors of the accident are catastrophic flood and wrecking earthquake. The flash flood, due to dam failure, will impact on nature, society and economy. The major environment risk areas are Jingzhou and Xiangfan,Hubei Province. The environment risk management measures should be adopted in order to ensure the safety of the project-environment complex system.