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.

ComGIS-Based Early Warning System of Rural Drinking Water Safety in Ya’an City of Sichuan, China

According to characteristic index of spatial-temporal variability of rural drinking water safety in Ya’an City of Sichuan, China, such as water quantity, water quality, convenience degree and guaranteed rate, etc., this study elaborated the basic framework, model’s methodology structure in early warning system of rural drinking water safety on the basis of ComGIS and initially designed information collection, search and re-trieval, evaluation and analysis of factors, dynamic prediction and dynamic early-warning and functions of guidance and management in this system. The design of this system provided scientific basis to grasp the state of rural drinking water safety timely, release early warning information and properly take necessary control measures, etc. The evaluation results showed that the overall trend was getting better. It proved that the rising pressure value and response value were main reasons which caused the rising evaluation value of rural drinking water safety.

Research on the Risk Associated with Rural Drinking Water Safety Based on Catastrophe Theory

In this study, based on the analysis of the catastrophic risk of rural drinking water, with the representative villages in Ya’an as study objects and setting the four evaluation standards: water quality, water quantity, the Guarantee Probability for water Supply and the Convenience Level of the Access to Water Supply as the ba- sic framework, a Rural Drinking Water Safety Assessment was developed (RDWSA). Research showed that Catastrophe Theory was applicable in the RDWSA. Adding RDWSA based on Catastrophe Theory to the supportive system for decision-making in Ecological Hydrographic Management Decision Support System of Ya’an helped obtain the rank and results of RDWSE by the automatic calculation of programs, which could assist the risk assessment and risk management associated with rural drinking water in Ya’an.

Integrated Control of Agricultural Non-point Source Pollution to Provide Safe and Healthy Drinking Water for Rural Areas

Agricultural non-point source pollution has become the main part of water pollution prevention and control in China. This paper made a brief introduction to the causes and hazards of agricultural non-point source pollution and the current situation of agricultural non-point source pollution prevention and control in China. In view of the serious agricultural non-point source pollution in water environment of Guangxi and the difference in quality of drinking water between urban and rural areas,it came up with recommendations for strengthening agricultural non-point source pollution prevention and control from scientific distribution,linked operation and maintenance,popular science education,and legal system construction,to guarantee safe and healthy drinking water in rural areas.

Design of Water Disinfection Scheme for Rural Drinking Water Safety Project

As further promotion of the rural drinking water safety project in whole country, small villages in vast countryside have been or will be equipped with safety drinking water project. We analyzed necessity of the rural drinking water disinfection, discussed disinfection method suitable for rural drinking water characteristics, and put forward disinfection schemes for different water supply sources.

Drinking water safety and the development of purification technology

This paper briefly introduced the evolution of purification technology for drinking water over time. After description of the 1st generation processes in the beginning of the 20th century - conventional processes and the 2nd generation processes in 1970s - advanced treatment processes, a tertiary processes - UF (ultrafiltration) based on integrated processes was proposed. Moreover, reaction measures (dosing variety of regents for different contaminants) for urban source water emergencies were illustrated in brief. A new technology of KMnO4 and potassium permanganate composite (PPC) for drinking water purification which was developed by Harbin Institute of Technology (HIT) was concisely introduced.

Water quality, agriculture and food safety in China:Current situation, trends, interdependencies, and management

Water quality in China is becoming a severe challenge for agriculture and food safety, and it might also impact health of population via agriculture and food. Thus, it is causing widespread concern. Based on extensive literatures review and data mining, current situation of water pollution in China and its effects on food safety were analyzed. The 2nd National Water Resource Survey in China show that the surface water all over the country was under slight pollution and about 60% of groundwater is polluted. Drinking water quality is basically guaranteed in urban area but it is worrisome in rural areas. In addition, China is the largest consumer of fertilizer and pesticide in the world and the amounts of application still show increasing trends. Fertilizers and pesticides are the most important sources of pollution, which affect human health as persistent organic pollutants and environmental endocrine disruptors. Eutrophication of surface water and nitrate pollution of groundwater are serious threats to drinking water safety. Sewage irrigation is becoming a pollution source to China＇s water and land because of lacking of effective regulations. Although, with the advance in technology and management level, control of nitrogen and phosphorus emissions and reducing water pollution is still a major challenge for China.

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.

Drinking Water Disparities in Tennessee: The Origins and Effects of Toxic Heavy Metals

Several toxic metals, commonly present in drinking water, are believed to play important roles in the development of cancerous tumors. Although the US Safe Drinking Water Act requires drinking water to meet health standards set by the Environmental Protection Agency, violations occur regularly. In this study, we have investigated the role of the two predominant toxic heavy metals identified in the drinking water sources in Tennessee: copper and lead. We have analyzed the levels of copper and lead, as well as the total water hardness among different counties of Tennessee, with different socioeconomic backgrounds. We determined that the effects of lead and copper in drinking water were random, although counties with typically lower average household incomes typically had higher levels of the metals. The contaminant levels were found to remain below the threshold established by the Environmental Protection Agency and the State of Tennessee. Water from the Cumberland River was harder than water obtained from other rivers in Tennessee. Furthermore, the total hardness of water did not correlate with the average household income of the various counties.

The Safety of Water Supplied at Njala University, Njala Campus

The safety of water is usually determined by comparing its quality to recommended standards. The objective of this work was to determine whether the water supplied on Njala Campus is safe for drinking. The quality parameters investigated include coliform bacteria, turbidity, conductivity, total dissolved solids and nitrates. Samples were stored in a cooler with ice and transported to the laboratory within 30 minutes of collection. A checklist of questions to know the perception of residents was administered. According to the physical and biological results, the water is not safe for consumption. The turbidity and microbial counts were too high in most samples both in the wet and dry seasons. Additionally, over 80% of the respondents did not trust the water supply system. Most of them treat the supplied water by either boiling or disinfection before use. Most respondents complained of water-borne diseases but were not clear whether it is related to the water supplied. The chemical parameters, however, were acceptable: nitrate levels were low. In conclusion, the water is not safe for consumption as far as the physical and biological parameters are concerned. The campus water supply system needs improvement in terms of conveying raw and finished water, filter optimization, and satisfying the chlorine demand.

Water Quality in the Gaza Strip: The Present Scenario

The Gaza Strip is one of the most densely populated areas in the world, 4505 people per km2 and the only source of water is represent by groundwater. The water quality in Gaza is very poor and the groundwater is affected by many different contaminants sources including soil/water interaction in the unsaturated zone due to recharge and return flows, mobilization of deep brines, sea water intrusion or upcoming and disposal of domestic and industrial wastes into the aquifer. Previous reports on the water quality in Gaza discussed the high levels of major ions (especially of chloride, nitrate and fluoride) in the drinking water. Moreover, little or no information is available for trace elements in the groundwater of the Gaza Strip. The sources of trace elements in groundwater could be natural and anthropogenic. 58 wells were sampled during July 2010, and were analyzed major ions and trace elements to check if the water quality is improving from the previous report. This study has revealed that no groundwater in Gaza Strip meets all WHO drinking water standards. The contaminants which affected the Gaza Strip are of different types and they originate from different sources. The environmental conditions are no safe for the population and some actions to improve the groundwater conditions are necessary to safeguard the population.

Comprehensive Control of Ecological Environment in Water Sources

To scientifically and effectively conduct comprehensive control of water sources to achieve water safety,the importance,main steps and plan of comprehensive control of ecological environment in water sources were analyzed on the basis of analyzing the development and protection process of foreign water sources.The results show that for the comprehensive control of water sources,it is needed to pay attention to the accurate grasp of the current environmental quality of water sources and carefully analyze the problems in the ecological environment of water sources.Besides,it is necessary to ensure the water quality and quantity of sources,focus on the implementation of environmental remediation and ecological restoration,implement regional protection of water sources,and combine engineering and non-engineering measures to take comprehensive control of environmental problems.

BAC滤池无脊椎动物滋生对饮用水安全性的影响

生物活性炭（Biological activated carbon，BAC）滤池能够为无脊椎动物提供理想的生境，但无脊椎动物可能给饮用水带来负面的健康效果和感观问题．2006年9月～2007年9月，对南方某水厂BAC滤池无脊椎动物滋生状况进行了为期13个月的调查研究，共发现无脊椎动物23种（属或类），优势类群为轮虫，其他类群还有桡足类、枝角类、寡毛类、无节幼体、线虫等．调查期间炭总管水无脊椎动物的平均密度是主臭氧后水的6．8倍．BAC滤池经过13个月的运行使用后，炭滤后水（1#和2#），炭层（#和2#），炭总管水无脊椎动物密度分别增长了3～17倍．BAC炭层富含无脊椎动物，最高密度可达52645个／k．相关性分析表明：水温对无脊椎动物生长有重要影响，夏季无脊椎动物密度通常高于冬季．这些发现表明：BAC滤池存在复杂的食物网关系，及由无脊椎动物引起的饮用水安全性风险．

基于SWOT-AHP模型的农村饮水安全发展环境分析与战略选择

本文在运用优势、劣势、机遇、威胁SWOT企业发展战略分析模型对农村饮水安全发展环境进行定性分析的同时,采用层次分析法(AHP)改进传统SWOT模型并进行定量分析,得出优势、劣势、机遇、威胁权重及各项评价指标权重。基于对指标优势力度进行测算,利用SWOT坐标分析法,对农村饮水安全内部和外部发展环境进行分析,并根据分析结果初步拟定了农村饮水发展战略选择路线及具体内容,对农村饮水安全健康发展,促进工程长效运行具有较强的现实意义。

我国南方桉树(Eucalyptus)人工林区水库突发性泛黑形成机理初探

桉树(Eucalyptus)在我国南方大规模种植,最快两三年成材,经济价值高,但近来却被认为是"抽水机"、"绿色沙漠",甚至传言"有毒".特别是近年来桉树人工林区水库出现的"泛黑"现象——水体呈现黑褐色并伴有涩味,给种植地附近居民造成了很大的恐慌.并且其黑水形成机理、物质来源及触发条件等尚不清楚.基于此,本文选取我国南方桉树人工林区典型水库,开展了水体"泛黑"现象成因研究:于2015年8月2016年4月对广西南宁市那降水库、天雹水库、百合水库分别进行了4次水体垂直分层采样,测定其理化指标,并结合当地水库管理站提供的水文数据进行综合分析.结果表明,桉树人工林区水库泛黑与特定季节及特殊气候条件有关,水体温度分层结构失稳是黑水物质运移的主要动力因素;夏季水库水温分层结构稳定,限制了底层致黑物质向上迁移,溶解氧等水质指标分层明显,秋冬季节分层消失,水体发生垂直交换,给底层致黑物质提供了上翻的作用力,导致"泛黑"现象发生.硫化物、单宁酸、铁、锰等物质季节性及空间分异特征与水温季节性分层特性密切相关.桉树林区水库水体铁和锰浓度最高可达2.93和3.46 mg/L,桉树茎、叶在水体中浸出大量单宁酸,在硫化物、单宁酸、铁、锰同时存在的条件下,发生铁、锰与硫化物,硫化物与单宁酸,铁、锰与单宁酸等一系列反应,生成黑色络合物,导致水库泛黑.研究结果可为保障桉树人工林区饮用水源地安全提供指导,并为桉树人工林区水库黑水深入研究奠定基础,引领更多学者进行深入研究.

基于机器学习模型的南宁盆地地下水中硝酸盐浓度预测及健康风险评价

地下水中硝酸盐污染已成为一个备受关注的全球性公共健康问题。本研究以南宁盆地为研究区域,采用逻辑回归、决策树及随机森林3种机器学习模型,结合降水量、氮肥施用量和人口密度等多种环境因子,构建了地下水中硝酸盐浓度的预测模型,预测了南宁盆地地下水中硝酸盐浓度的空间分布,并评估了其对不同人群的健康风险。结果表明:随机森林模型的预测性能优于其他模型,其R^(2)值为0.736,RMSE和MAE分别为2.736和2.077;南宁盆地大部分地下水中硝酸盐浓度处于安全范围内,但约16.14%的区域存在污染风险,这些区域主要分布在农业区;婴儿和儿童通过饮水摄入硝酸盐的非致癌健康风险超过了可接受范围,尤其是在污染较为严重的南宁盆地西南部和东部地区。本研究为岩溶地区地下水污染管理和公共健康保护提供了科学依据。

Characterizing the photodegradation-induced release of volatile organic compounds from bottled water containers

While plastic water bottles are known to potentially release various volatile organic compounds(VOCs)when exposed to light,existing knowledge in this field remains limited.In this study,we systematically examined the composition,yield,and toxicity of VOCs released from six plastic containers obtained from different continents under UV-A and solar irradiation.After light exposure,all containers released VOCs,including alkanes,alkenes,alcohols,aldehydes,carboxylic acids,aromatics,etc.The 1#,3#,4#,5#,and 6#containers exhibited 35,32,19,24 and 37 species of VOCs,respectively.Specifically,the 2#container released 28 and 32 series of VOCs after 1-day(short-term)and 7-day(long-term)UV-A irradiation,respectively,compared to 30 and 32 species under solar irradiation.Over half of the VOCs identified were oxidized compounds alongside various short-chain hydrocarbons.Significant differences in VOC compositions among the containers were observed,potentially originating from light-induced aging and degradation of the polyethylene terephthalate structure in the containers.Toxicological predictions unveiled distinctive toxic characteristics of VOCs from each container.For example,among the various VOCs produced by the 2#container,straight-chain alkanes like n-hexadecane(544-76-3)were identified as the most toxic compounds.After long-term irradiation,the yield of these toxic VOCs from the 2#container ranged from 0.11 ng/g to 0.79 ng/g.Considering the small mass of a single bottle,the volatilization of VOCs from an individual container would be insignificant.Even after prolonged exposure to light,the potential health risks associated with inhaling VOCs when opening and drinking bottled water appear manageable.

2021—2023年某地区农村生活饮用水微生物检测结果分析

目的:分析讨论某地区2021—2023年农村生活饮用水中微生物指标的检测结果,评估水质安全状况,并提出改进对策。方法:在该地区设置水质监测点,每年丰水期和枯水期各采集一次水样,共检测394份水样。检测指标包括细菌总数、总大肠菌群以及大肠埃希菌,依据《生活饮用水卫生标准》(GB 5749—2006)进行评价。结果:该地区农村生活饮用水2021—2023年不合格率呈现出逐年下降的趋势,总不合格率为18.02%。不同水期(丰水期和枯水期)的微生物指标不合格率也呈现出逐年下降的趋势。结论:该地区农村生活饮用水的水质安全状况有一定程度改善,但仍需要针对水质加强监测和管理,为农村居民的饮水提供安全保障。

Development and application of innovative technologies for drinking water quality assurance in China

The continuously deteriorating quality of source water is threatening the safety of drinking water in China.Various efforts have been made to update water treatment processes to decrease the pollution problems of drinking water,such as protection of drinking water sources,enhance-ment of conventional treatment processes,and development of new or advanced treatment technologies.This paper reviews a variety of protection and remediation methods for drinking water sources,development and application of drinking water treatment technologies,new technologies for special pollutants removal from groundwater,and the latest research progress on water distribution systems in China.

Review on corrosion and corrosion scale formation upon unlined cast iron pipes in drinking water distribution systems

The qualified finished water from water treatment plants(WTPs) may become discolored and deteriorated during transportation in drinking water distribution systems(DWDSs), which affected tap water quality seriously. This water stability problem often occurs due to pipe corrosion and the destabilization of corrosion scales. This paper provides a comprehensive review of pipe corrosion in DWDSs, including corrosion process, corrosion scale formation, influencing factors and monitoring technologies utilized in DWDSs. In terms of corrosion process, corrosion occurrence, development mechanisms, currently applied assays, and indices used to determine the corrosion possibility are summarized, as well as the chemical and bacterial influences. In terms of scale formation, explanations for the nature of corrosion and scale formation mechanisms are discussed and its typical multilayered structure is illustrated. Furthermore, the influences of water quality and microbial activity on scale transformation are comprehensively discussed. Corrosion-related bacteria at the genus level and their associated corrosion mechanism are also summarized. This review helps deepen the current understanding of pipe corrosion and scale formation in DWDSs, providing guidance for water supply utilities to ensure effective measures to maintain water quality stability and guarantee drinking water safety.