Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as ...Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as they tend to be laborious,time-consuming,or technically difficult.Disinfection byproducts(DBPs)are a family of well-known secondary pollutants formed by the reactions of chemical disinfectants with DBP precursors during water disinfection treatment.Since DBP precursors have various origins(e.g.,natural,domestic,industrial,and agricultural sources),and since the formation of DBPs from different precursors in the presence of specific disinfectants is distinctive,we argue that DBPs and DBP precursors can serve as alternative indicators to assess the contamination in water sources and identify pollution origins.After providing a retrospective of the origins of DBPs and DBP precursors,as well as the specific formation patterns of DBPs from different precursors,this article presents an overview of the impacts of various natural and anthropogenic factors on DBPs and DBP precursors in drinking water sources.In practice,the DBPs(i.e.,their concentration and speciation)originally present in source water and the DBP precursors determined using DBP formation potential tests—in which water samples are dosed with a stoichiometric excess of specific disinfectants in order to maximize DBP formation under certain reaction conditions—can be considered as alternative metrics.When jointly used with other water quality parameters(e.g.,dissolved organic carbon,dissolved organic nitrogen,fluorescence,and molecular weight distribution)and specific contaminants of emerging concern(e.g.,certain pharmaceuticals and personal care products),DBPs and DBP precursors in drinking water sources can provide a more comprehensive picture of water pollution for better managing water resources and ensuring human health.展开更多
An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In t...An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.展开更多
The protection of drinking water sources is vital to urban development and public health.In this study,the current situation of the mandatory protection area for drinking water source in the Pearl River Delta region w...The protection of drinking water sources is vital to urban development and public health.In this study,the current situation of the mandatory protection area for drinking water source in the Pearl River Delta region was investigated using a method combining Google Earth with the field survey.The gaps between management practices and legislation requirements were analyzed.Finally,several countermeasures for water resource protection were proposed as follows:to promote delineation in a more scientific way,to safeguard the sanctity of the law,to make better plan on water saving,and to encourage public participation in supervision and management.展开更多
The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source s...The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference （P 〈 0.01） was observed when compared with the solvent control, The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks （at town level） was the most serious, the arbitrary units （AU） was 141.62±6.96, however, that of Shangyuanmen waterworks （at city level） was only 109.64±2.97. The analysis also revealed that the genotoxicity of town＇s water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.展开更多
Supervision of urban water source area and the safety of drinking water is one of the important tasks in China's current environmental protection work. By reviewing screening methods of characteristic pollutants i...Supervision of urban water source area and the safety of drinking water is one of the important tasks in China's current environmental protection work. By reviewing screening methods of characteristic pollutants in urban water source area,screening system of pollutants based on the framework of environmental risk is introduced in detail: establish database of pollutants→determine the evaluation purpose→determine testing end and screening standard→assignment calculation→prioritization. At the same time,the application of health risk assessment and technology in the risk assessment of urban water source area is introduced,so as to provide technical support and theoretical basis for management and protection of urban water source area.展开更多
Sustaining a reliable and contaminant-free drinking water is becoming an increasing challenge worldwide due to human activity, industrial waste, and agricultural overuse. Surface water is the main source of drinking w...Sustaining a reliable and contaminant-free drinking water is becoming an increasing challenge worldwide due to human activity, industrial waste, and agricultural overuse. Surface water is the main source of drinking water around the world. However, groundwater is also becoming increasingly popular, due to its clarity and minimal need for processing to reduce turbidity. Over the years, the demand and growth in the agricultural industry has also been the means of groundwater contamination. Due to the health burden that raw water can pose, water must be processed and purified prior to consumption. Raw water quality can be compromised by physical, chemical (heavy metals and disinfection by-products), and biological contaminants. Biological contaminants can significantly impact immunocompromised populations, while chemical contaminants can impact the growth and development of young children. Although obtaining a steady and high-quality water flow to the general population is an increasing challenge, developed countries have utilized state-of-the-art technologies and techniques to provide contaminant-free water to their citizens. This research aims to provide information about the regulatory parameters, characteristics, and sources of safe drinking water in the world as a model for future use in the developing world. In this, secondary data was used to compare and contrast drinking water quality among countries in the European Union, the United States, Canada, the United Kingdom, Singapore, New Zealand, Australia, Qatar, and the United Arab Emirates. The data indicates that Ireland and the United Kingdom have relatively lower amounts of contaminants in their drinking water. Upon completing this research, it is recommended that countries desiring clean drinking water systems should initiate and invest in programs that control and protect treatment plants, water distribution systems, water sources, and catchments.展开更多
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 ...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.展开更多
Ecological compensation mechanism for drinking water source is one of the effective economic ways to solve the issues of the shortage of the protection investment and the lack of the driving forces to protect the wate...Ecological compensation mechanism for drinking water source is one of the effective economic ways to solve the issues of the shortage of the protection investment and the lack of the driving forces to protect the water quality.The successful cases of compensation mechanism for drinking water source have examined the dilemma of improving the trans-administrative boundary compensation mechanism both in China and Yunnan.The lack of the provincial rules and regulations in Yunnan is the fundamental reason for the local government not willingly to establish the compensation mechanism.On the other hand,the shortage of the compensation funds is the key difficulty for the shareholders to reach an agreement.Formulating the rules and regulations about the construction of the compensation mechanism of drinking water source in Yunnan would be a feasible way to stipulate the local government to set up the compensation mechanism.Meanwhile,designing a complete set of compensation mechanism would make full use of the mechanism to work well to protect the water quality in an economic way.展开更多
Riparian land use/land cover(LULC)plays a crucial role in maintaining riverine water quality by altering the transport of pollutants and nutrients.Nevertheless,establishing a direct relationship between water quality ...Riparian land use/land cover(LULC)plays a crucial role in maintaining riverine water quality by altering the transport of pollutants and nutrients.Nevertheless,establishing a direct relationship between water quality and LULC is challenging due to the multi-indicator nature of both factors.Water quality encompasses a multitude of physical,chemical,and biological parameters,while LULC represents a diverse array of land use types.Riparian habitat quality(RHQ)serves as an indicator of LULC.Yet,it remains to be seen whether RHQ can act as a proxy of LULC for assessing the impact of LULC on riverine water quality.This study examines the interplay between RHQ,LULC and water quality,and develops a comprehensive indicator to predict water quality.We measured several water quality parameters,including pH(potential of hydrogen),TN(total nitrogen),TP(total phosphorus),T_(water)(water temperature),DO(dissolved oxygen),and EC(electrical conductivity)of the Yue and Jinshui Rivers draining to the Han River during 2016,2017 and 2018.The water quality index(WQI)was further calculated.RHQ is assessed by the InVEST(Integrated Valuation of Ecosystem Services and Tradeoffs)model.Our study found noticeable seasonal differences in water quality,with a higher WQI observed in the dry season.The RHQ was strongly correlated with LULC compositions.RHQ positively correlated with WQI,and DO concentration and vegetation land were negatively correlated with T_(water),TN,TP,EC,cropland,and construction land.These correlations were stronger in the rainy season.Human-dominated land,such as construction land and cropland,significantly contributed to water quality degradation,whereas vegetation promoted water quality.Regression models showed that the RHQ explained variations in WQI better than LULC types.Our study concludes that RHQ is a new and comprehensive indicator for predicting the dynamics of riverine water quality.展开更多
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 poll...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.展开更多
The study assessed the physico-chemical quality of selected drinking water sources (springs, boreholes, shallow wells and rainfall) in Mbarara municipality with respect to World Health Organization (WHO) drinking wate...The study assessed the physico-chemical quality of selected drinking water sources (springs, boreholes, shallow wells and rainfall) in Mbarara municipality with respect to World Health Organization (WHO) drinking water guidelines and other guidelines in light of the increased anthropogenic activities in the municipality. A total of 70 water samples were collected from purposively selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality with various human activities. The samples were analysed for physico-chemical parameters: Temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Electrical Conductivity (EC) and Total hardness using American Public Health Association (APHA) standard methods. The mean temperature and pH ranged between 18.07 °C - 23.45 °C and 5.74 - 7.54, respectively. The mean DO values were found to be between 4.84 and 12.86 mg/l;whereas mean BOD was within the range of 1.83 - 7.71 mg/l. The mean TDS and EC of the water samples ranged, between 33.40 - 569.20 mg/l and 29.30 - 1139.90 μS/cm respectively. Furthermore, the lowest and highest mean total hardness were 70.00 and 264.00 mg/l, respectively. The recorded mean water temperatures for each of the water sources were above the WHO threshold temperature (15 °C) which makes drinking water palatable. Boreholes in Nyamitanga and Shuhaddea Secondary Schools, spring in Kiswahili, well in Kisenyi and rainwater in Mbarara University of Science and Technology (MUST) had mean pH below the WHO minimum guideline value (6.5) hence acidic. Borehole in Nyamitanga secondary school, spring in Kisenyi, shallow well in Nyamitanga and the rainwater in MUST had mean DO values below the WHO range (10 - 12 mg/l). Borehole in Shuhaddea Secondary School and the well in Kisenyi had average BOD values above the range of European Union guideline values (3 - 6 mg/l). TDS and EC of all the water sources were below the WHO maximum guideline limits of 1000 mg/l and 1500 μs/cm respectively. Total hardness was also below the WHO harmless limit of 1000 mg/l. However rainwater in MUST was moderately soft while the other drinking water sources exhibited moderate to full total hardness. The physicochemical parameters of some of the selected water sources in Mbarara municipality have been compromised mainly by the increased human activities especially croplands, latrines, landfills, transportation, animal and municipal wastes at the vicinity of the water sources. Mbarara municipal council should therefore ensure proper sanitation and water safety plans for these drinking water sources to avoid further contamination from the human activities.展开更多
Surveillance of water quality to ensure microbiological safety is a vital public health function to prevent water borne diseases. Bacterial total coliform and Escherichia coli (E. coli) examination provide indication ...Surveillance of water quality to ensure microbiological safety is a vital public health function to prevent water borne diseases. Bacterial total coliform and Escherichia coli (E. coli) examination provide indication of the hygienic condition of drinking water and are major tools in the assessment of the health risk borne by pathogen in water. Unfortunately, there is insufficient information on the total coliform and E. coli amounts in the common drinking water sources in Mbarara Municipality, Uganda despite the eminent anthropogenic sources of contamination. Hence the study established the sanitary risk and quantified the total coliform and E. coli load in selected drinking water sources in Mbarara Municipality, Uganda. A total of 70 water samples were collected from selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality. The water samples were analysed for total coliform and E. coli abundance using the American Public Health Association (APHA) standard method. The total coliform and Escherichia coli counts were compared with the World Health Organization (WHO) drinking water standard guidelines. The findings indicate that all the studied groundwater sources (boreholes, springs and wells) in Mbarara Municipality were not compliant to either both or one of the WHO total coliform ( ml) and E. coli (0 CFU/100 ml) criteria for drinking water hence they are unsuitable for drinking without treatment e.g. boiling etc. Only rainwater collected from Mbarara University of Science and Technology met the WHO total coliform and E. coli criteria for drinking water thus is suitable for drinking without any treatment. There is a strong linkage between bacterial (total coliforms and E. coli) water quality and water source sanitation, as well as the proximity of latrines, animal farms and landfills around the water sources. Mbarara municipal council should therefore ensure effective and regular operation and maintenance of the drinking water sources through the adoption and promotion of appropriate water safety plans.展开更多
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 Dist...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.展开更多
This study determined the physico-chemical and bacterial quality of raw (bore-hole, springs, wells) and tap water sources from Nyaruzinga wetland for domestic use in Bushenyi Municipality. Forty samples of raw water w...This study determined the physico-chemical and bacterial quality of raw (bore-hole, springs, wells) and tap water sources from Nyaruzinga wetland for domestic use in Bushenyi Municipality. Forty samples of raw water were randomly collected from Kacuncu, Kyeitembe and Kikuba tributaries of the wetland and 40 samples of tap water generated from the same wetland were randomly drawn from Ishaka, Nyakabirizi and Central divisions of the Municipality. The samples were analyzed for apparent colour (AC), turbidity, electrical conductivity (EC), total hardness, pH, total iron, residual alum, free residual chlorine and faecal coliforms using standard methods and their values compared with standard local UNBS (2008) and international WHO (2011) drinking water quality guidelines. The results showed that the mean pH of the protected spring below Kikuba Hill (5.21);the AC (Pt/Co) of the borehole below Bweranyangi Junior School (17.28) and the surface well below Nyandozo Primary School (157.58) both situated in Kacuncu as well as the free residual chlorine (mg/L) in tap water at Kanyamabona Trading Centre, Ishaka division (0.192) were below the standard values of WHO (pH, 6.0 - 8.0;free residual chlorine, 0.2 - 0.5) and UNBS (AC, <15). The electrical conductivity, EC (μS/cm) and total hardness (mg/L) of all the selected water sources were within the WHO standards (EC, <1500 (raw water), 0 - 300 (tap water);total hardness, <1500 (raw water), <100 (tap water)). The residual alum (mg/L) in all the tap water sources was also within the WHO guideline (<0.2). On the other hand, the turbidity (27.38 NTUs) and total iron content (0.32 mg/L) of the surface well below Nyandozo Primary School were above WHO guidelines of <15 and <0.3 respectively. Furthermore, the mean faecal coliform counts (CFU/100 ml) in the surface well below Nyandozo Primary School (6.90) and the borehole below Bweranyangi Junior School (16.83) including the surface well below Kyeitembe Trading Centre (9.25) were above the WHO standard faecal coliform count (≤3 TCUs). Only the tap water at Kanyamabona Trading Centre recorded mean faecal coliform counts (0.25 TCUs) beyond the WHO standard (0 TCU). Hence the quality of tap water within the municipality tapped from Nyaruzinga wetland was generally better than the raw drinking water sources (borehole, springs, wells) from the same wetland. Thus the use of piped tap water by the urban inhabitants as opposed to raw water sources needs to be promoted to increase access to safe water.展开更多
Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biologica...Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biological properties. This study investigates the suitability of groundwater for domestic and irrigational purposes through physico-chemical and bacteriological analyses in the Northern part of Bamenda Town (Cameroon). Thus, 20 groundwater samples were collected from hand-dug wells and spring sources in September 2018 (rainy season) and February 2019 (dry season) and physico-chemical and bacteriological characteristics were determined. The results revealed that pH ranged from 5.5 to 6.6, thus enabling the classification of the water as slightly acidic. Electrical conductivity varied between 0.01 - 0.06 μS/cm. The relative abundance of ions was such that Ca<sup>2+</sup> > K<sup>+</sup> > Mg<sup>2+</sup> > Na<sup>+</sup> for cations and <span style="white-space:nowrap;">HCO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > Cl<sup>-</sup> > <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > <span style="white-space:nowrap;">SO<sup>-</sup><sub style="margin-left:-7px;">4</sub></span> for anions. The water types were Ca-Mg-NO<sub>3</sub> in both dry and rainy seasons. The results revealed that the mechanisms controlling groundwater chemistry are rock weathering and atmospheric precipitation. Indicator bacteria such as <em>E. coli</em>, <em>Shigella</em>, <em>Enterobacteria</em>, <em>Vibrio</em>, <em>Streptococcus</em> and <em>Staphylococcus</em> were detected in the studied groundwater samples, thus the water sources may pose a threat to public health.展开更多
A preliminary study was conducted to analyze the water quality of spring waters in rural watershed of Western Nepal. 155 spring water samples were collected from Jhimruk, Rangun, Bogtan-Lagam Karnali, Thuligad and Mid...A preliminary study was conducted to analyze the water quality of spring waters in rural watershed of Western Nepal. 155 spring water samples were collected from Jhimruk, Rangun, Bogtan-Lagam Karnali, Thuligad and Middle Karnali watershed. Collection and analysis occurred twice, once in pre-monsoon 2018 and post-monsoon 2018. Various physical and chemical parameters were analyzed by using standard water quality measurements and compared with the Nepal Drinking Water Quality Standard and the World Health Organization Standard Guideline. The results indicate that the turbidity was high during pre-monsoon season. The highest turbidity of 63.8 NTU was observed in the Bogtan-Lagam Karnali watershed. Two spring sources—one in Bogtan-Lagam Karnali and one in Middle Karnali exceeded the health standard for nitrate-N. The phosphate levels were high during the pre-monsoon season in Jhimruk and Rangun watershed in all the studied sites. Dissolved oxygen levels were relatively high during post-monsoon season. Results of the water quality index in all the studied sites revealed that the water quality ranges from being poor to good conditions in the spring sources. The results from this study suggested that the water bodies are relatively good and can be used for domestic purposes after suitable treatment.展开更多
The etiology for the high tumor mortality in heavy polluted Yinghe river basin is still unclear and polycyclic aromatic hydrocarbons(PAHs)belong to the priority pollutants in water based on the former surveillance dat...The etiology for the high tumor mortality in heavy polluted Yinghe river basin is still unclear and polycyclic aromatic hydrocarbons(PAHs)belong to the priority pollutants in water based on the former surveillance data.In order to explore the potential genotoxicants contributing to the double-endpoint genotoxicity of polluted drinking water source,12 groundwater and 3 surface water samples were collected from 3 villages and the nearby rivers alongside Yinghe river basin,respectively and their comprehensive genotoxicity was estimated with a bioassay group of sOS/umu test and micronucleus(MN)test(MNT).Some groundwater samples showed positive genotoxicity and all surface water samples were highly genotoxic.Eight groundwater samples showed DNA genotoxic effct with the average 4-NQO equivalent concentration(TEQ_(4-NQO))of 0.067μg/L and 0.089μg/L in wet and dry season,respectively.The average MN ratios of groundwater samples were 14.19‰ and 17.52‰ in wet and dry season,respectively.Groundwater samples showed different genotoxic effect among 3 villages.The total PAHs concentrations in all water samples ranged from 8.98 to 25.17 ng/L with an average of 14.97±4.85 ng/L.BaA,CHR,BkF,BaP and DBA were the main carcinogenic PAHs contributing to the genotoxicity of water samples.In conclusion,carcinogenic PAHs are possibly related to the high tumor mortality in the target area.Characterization of carcinogenic PAHs to genotoxicity of drinking water source may shed light on the etiology study for high tumor mortality in Yinghe river basin.Key words:genotoxicity test;drinking water source;high tumor mortality;Yinghe river basin;polycyclic aromatic hydrocarbons(PAHs)展开更多
The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source fo...The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source for water supply of Ivan^ice and Rosice towns and provides water for 30,000 inhabitants. The risk analysis was created on the basis of water quality monitoring, hydrogeological assessment and terrain exploration and a revision of protection zones was proposed. The spring area is situated in nitrate vulnerable zones and recently nitrate concentrations have been decreasing. Water quality evaluation results： high concentration of manganese and iron, sometimes higher concentration of ammonium and COD. This area is intensively used for agriculture and it is necessary to make a compromise solution during protection zones proposal, The regime in protection zones can not affect manganese and iron concentration （their origin is in the natural geological environment）. Therefore, water treatment plant is in operation and its modernization is proposed. Furthermore, the paper deals with spring area intensification construction of a new hydrologic borehole, and managed and unmanaged infiltration of surface water. The proposal of protection zones revision consists of reduction to a 2nd level protection zone.展开更多
Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have be...Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have been analyzed in order to provide theoretical bases for prevention and reduction of eutrophication. The analyzed results show that nitrogen forms in the influent area of the reservoir are given priority to ammonia nitrogen and nitrate nitrogen, whose proportion is more than 45% respectively, and this is probably caused by the pollution of inflow water quality;but in the effluent area, the forms are given priority to nitrate nitrogen, whose proportion is as high as 96% and above;also the proportion of ammonia nitrogen drops by more than 80% during the process from the influent area to the effluent area, and this shows that the natural process of nitrification and denitrification can be well accomplished in the reservoir. We recommend here that to reduce the input amount of ammonia nitrogen and organic nitrogen into the reservoir is the most efficient way to prevent or mitigate eutrophication of water body.展开更多
基金supported by the National Natural Science Foundation of China(52325001,52170009,and 52091542)the National Key Research and Development Program of China(2021YFC3200700)+3 种基金the Program of Shanghai Academic Research Leader,China(21XD1424000)the International Cooperation Project of Shanghai Science and Technology Commission(20230714100)the Key-Area Research and Development Program of Guangdong Province(2020B1111350001)Tongji University Youth 100 Program.
文摘Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as they tend to be laborious,time-consuming,or technically difficult.Disinfection byproducts(DBPs)are a family of well-known secondary pollutants formed by the reactions of chemical disinfectants with DBP precursors during water disinfection treatment.Since DBP precursors have various origins(e.g.,natural,domestic,industrial,and agricultural sources),and since the formation of DBPs from different precursors in the presence of specific disinfectants is distinctive,we argue that DBPs and DBP precursors can serve as alternative indicators to assess the contamination in water sources and identify pollution origins.After providing a retrospective of the origins of DBPs and DBP precursors,as well as the specific formation patterns of DBPs from different precursors,this article presents an overview of the impacts of various natural and anthropogenic factors on DBPs and DBP precursors in drinking water sources.In practice,the DBPs(i.e.,their concentration and speciation)originally present in source water and the DBP precursors determined using DBP formation potential tests—in which water samples are dosed with a stoichiometric excess of specific disinfectants in order to maximize DBP formation under certain reaction conditions—can be considered as alternative metrics.When jointly used with other water quality parameters(e.g.,dissolved organic carbon,dissolved organic nitrogen,fluorescence,and molecular weight distribution)and specific contaminants of emerging concern(e.g.,certain pharmaceuticals and personal care products),DBPs and DBP precursors in drinking water sources can provide a more comprehensive picture of water pollution for better managing water resources and ensuring human health.
基金The Society Development Foundation of Jiangsu Province (No. BS2001039)
文摘An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.
文摘The protection of drinking water sources is vital to urban development and public health.In this study,the current situation of the mandatory protection area for drinking water source in the Pearl River Delta region was investigated using a method combining Google Earth with the field survey.The gaps between management practices and legislation requirements were analyzed.Finally,several countermeasures for water resource protection were proposed as follows:to promote delineation in a more scientific way,to safeguard the sanctity of the law,to make better plan on water saving,and to encourage public participation in supervision and management.
文摘The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference （P 〈 0.01） was observed when compared with the solvent control, The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks （at town level） was the most serious, the arbitrary units （AU） was 141.62±6.96, however, that of Shangyuanmen waterworks （at city level） was only 109.64±2.97. The analysis also revealed that the genotoxicity of town＇s water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.
基金Supported by Key Project of Hebei Science and Technology Plan(15273604D)
文摘Supervision of urban water source area and the safety of drinking water is one of the important tasks in China's current environmental protection work. By reviewing screening methods of characteristic pollutants in urban water source area,screening system of pollutants based on the framework of environmental risk is introduced in detail: establish database of pollutants→determine the evaluation purpose→determine testing end and screening standard→assignment calculation→prioritization. At the same time,the application of health risk assessment and technology in the risk assessment of urban water source area is introduced,so as to provide technical support and theoretical basis for management and protection of urban water source area.
文摘Sustaining a reliable and contaminant-free drinking water is becoming an increasing challenge worldwide due to human activity, industrial waste, and agricultural overuse. Surface water is the main source of drinking water around the world. However, groundwater is also becoming increasingly popular, due to its clarity and minimal need for processing to reduce turbidity. Over the years, the demand and growth in the agricultural industry has also been the means of groundwater contamination. Due to the health burden that raw water can pose, water must be processed and purified prior to consumption. Raw water quality can be compromised by physical, chemical (heavy metals and disinfection by-products), and biological contaminants. Biological contaminants can significantly impact immunocompromised populations, while chemical contaminants can impact the growth and development of young children. Although obtaining a steady and high-quality water flow to the general population is an increasing challenge, developed countries have utilized state-of-the-art technologies and techniques to provide contaminant-free water to their citizens. This research aims to provide information about the regulatory parameters, characteristics, and sources of safe drinking water in the world as a model for future use in the developing world. In this, secondary data was used to compare and contrast drinking water quality among countries in the European Union, the United States, Canada, the United Kingdom, Singapore, New Zealand, Australia, Qatar, and the United Arab Emirates. The data indicates that Ireland and the United Kingdom have relatively lower amounts of contaminants in their drinking water. Upon completing this research, it is recommended that countries desiring clean drinking water systems should initiate and invest in programs that control and protect treatment plants, water distribution systems, water sources, and catchments.
文摘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.
文摘Ecological compensation mechanism for drinking water source is one of the effective economic ways to solve the issues of the shortage of the protection investment and the lack of the driving forces to protect the water quality.The successful cases of compensation mechanism for drinking water source have examined the dilemma of improving the trans-administrative boundary compensation mechanism both in China and Yunnan.The lack of the provincial rules and regulations in Yunnan is the fundamental reason for the local government not willingly to establish the compensation mechanism.On the other hand,the shortage of the compensation funds is the key difficulty for the shareholders to reach an agreement.Formulating the rules and regulations about the construction of the compensation mechanism of drinking water source in Yunnan would be a feasible way to stipulate the local government to set up the compensation mechanism.Meanwhile,designing a complete set of compensation mechanism would make full use of the mechanism to work well to protect the water quality in an economic way.
基金supported by the National Natural Science Foundation of China(Grant No.31670473)the Wuhan Institute of Technology funding to Dr.Siyue Li(Grant No.21QD02).
文摘Riparian land use/land cover(LULC)plays a crucial role in maintaining riverine water quality by altering the transport of pollutants and nutrients.Nevertheless,establishing a direct relationship between water quality and LULC is challenging due to the multi-indicator nature of both factors.Water quality encompasses a multitude of physical,chemical,and biological parameters,while LULC represents a diverse array of land use types.Riparian habitat quality(RHQ)serves as an indicator of LULC.Yet,it remains to be seen whether RHQ can act as a proxy of LULC for assessing the impact of LULC on riverine water quality.This study examines the interplay between RHQ,LULC and water quality,and develops a comprehensive indicator to predict water quality.We measured several water quality parameters,including pH(potential of hydrogen),TN(total nitrogen),TP(total phosphorus),T_(water)(water temperature),DO(dissolved oxygen),and EC(electrical conductivity)of the Yue and Jinshui Rivers draining to the Han River during 2016,2017 and 2018.The water quality index(WQI)was further calculated.RHQ is assessed by the InVEST(Integrated Valuation of Ecosystem Services and Tradeoffs)model.Our study found noticeable seasonal differences in water quality,with a higher WQI observed in the dry season.The RHQ was strongly correlated with LULC compositions.RHQ positively correlated with WQI,and DO concentration and vegetation land were negatively correlated with T_(water),TN,TP,EC,cropland,and construction land.These correlations were stronger in the rainy season.Human-dominated land,such as construction land and cropland,significantly contributed to water quality degradation,whereas vegetation promoted water quality.Regression models showed that the RHQ explained variations in WQI better than LULC types.Our study concludes that RHQ is a new and comprehensive indicator for predicting the dynamics of riverine water quality.
基金Supported by State Key Research and Development Program of Ministry of Science and Technology"Soil Passivation-Physiological Barrier-Enrichment and Removal Technology in Paddy Field with Mild Cadmium Contamination"(2016YED0800705-01)Key Research and Development Program of Guangxi"Research and Demonstration of Remediation Technology in Cadmium and Lead Polluted Paddy Field"(Gui Ke AB16380084)+2 种基金Key Agricultural Science and Technology Project of Guangxi"Integration,Research and Development of Heavy Metal Pollution Prevention Technology for Paddy Field"(201528)Scientific Research and Technological Development Program Project of Nanning City"Research and Demonstration of Integrated Ecological Restoration Technology for Heavy Metal Cadmium Polluted Paddy Field in Nanning"(20162105)Scientific and Technological Service Ability and Party Informationization Construction of Ecological Comprehensive Demonstration Village in Jianning No.1 Team of Xixiangtang District of Nanning(20152054-13)
文摘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.
文摘The study assessed the physico-chemical quality of selected drinking water sources (springs, boreholes, shallow wells and rainfall) in Mbarara municipality with respect to World Health Organization (WHO) drinking water guidelines and other guidelines in light of the increased anthropogenic activities in the municipality. A total of 70 water samples were collected from purposively selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality with various human activities. The samples were analysed for physico-chemical parameters: Temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Electrical Conductivity (EC) and Total hardness using American Public Health Association (APHA) standard methods. The mean temperature and pH ranged between 18.07 °C - 23.45 °C and 5.74 - 7.54, respectively. The mean DO values were found to be between 4.84 and 12.86 mg/l;whereas mean BOD was within the range of 1.83 - 7.71 mg/l. The mean TDS and EC of the water samples ranged, between 33.40 - 569.20 mg/l and 29.30 - 1139.90 μS/cm respectively. Furthermore, the lowest and highest mean total hardness were 70.00 and 264.00 mg/l, respectively. The recorded mean water temperatures for each of the water sources were above the WHO threshold temperature (15 °C) which makes drinking water palatable. Boreholes in Nyamitanga and Shuhaddea Secondary Schools, spring in Kiswahili, well in Kisenyi and rainwater in Mbarara University of Science and Technology (MUST) had mean pH below the WHO minimum guideline value (6.5) hence acidic. Borehole in Nyamitanga secondary school, spring in Kisenyi, shallow well in Nyamitanga and the rainwater in MUST had mean DO values below the WHO range (10 - 12 mg/l). Borehole in Shuhaddea Secondary School and the well in Kisenyi had average BOD values above the range of European Union guideline values (3 - 6 mg/l). TDS and EC of all the water sources were below the WHO maximum guideline limits of 1000 mg/l and 1500 μs/cm respectively. Total hardness was also below the WHO harmless limit of 1000 mg/l. However rainwater in MUST was moderately soft while the other drinking water sources exhibited moderate to full total hardness. The physicochemical parameters of some of the selected water sources in Mbarara municipality have been compromised mainly by the increased human activities especially croplands, latrines, landfills, transportation, animal and municipal wastes at the vicinity of the water sources. Mbarara municipal council should therefore ensure proper sanitation and water safety plans for these drinking water sources to avoid further contamination from the human activities.
文摘Surveillance of water quality to ensure microbiological safety is a vital public health function to prevent water borne diseases. Bacterial total coliform and Escherichia coli (E. coli) examination provide indication of the hygienic condition of drinking water and are major tools in the assessment of the health risk borne by pathogen in water. Unfortunately, there is insufficient information on the total coliform and E. coli amounts in the common drinking water sources in Mbarara Municipality, Uganda despite the eminent anthropogenic sources of contamination. Hence the study established the sanitary risk and quantified the total coliform and E. coli load in selected drinking water sources in Mbarara Municipality, Uganda. A total of 70 water samples were collected from selected boreholes, springs, wells and rainwater in Nyamitanga, Kamukuzi and Kakoba divisions of Mbarara municipality. The water samples were analysed for total coliform and E. coli abundance using the American Public Health Association (APHA) standard method. The total coliform and Escherichia coli counts were compared with the World Health Organization (WHO) drinking water standard guidelines. The findings indicate that all the studied groundwater sources (boreholes, springs and wells) in Mbarara Municipality were not compliant to either both or one of the WHO total coliform ( ml) and E. coli (0 CFU/100 ml) criteria for drinking water hence they are unsuitable for drinking without treatment e.g. boiling etc. Only rainwater collected from Mbarara University of Science and Technology met the WHO total coliform and E. coli criteria for drinking water thus is suitable for drinking without any treatment. There is a strong linkage between bacterial (total coliforms and E. coli) water quality and water source sanitation, as well as the proximity of latrines, animal farms and landfills around the water sources. Mbarara municipal council should therefore ensure effective and regular operation and maintenance of the drinking water sources through the adoption and promotion of appropriate water safety plans.
基金Supported by Scientific Research Planning Project of Beibei District,Chongqing City(2017-18)
文摘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.
文摘This study determined the physico-chemical and bacterial quality of raw (bore-hole, springs, wells) and tap water sources from Nyaruzinga wetland for domestic use in Bushenyi Municipality. Forty samples of raw water were randomly collected from Kacuncu, Kyeitembe and Kikuba tributaries of the wetland and 40 samples of tap water generated from the same wetland were randomly drawn from Ishaka, Nyakabirizi and Central divisions of the Municipality. The samples were analyzed for apparent colour (AC), turbidity, electrical conductivity (EC), total hardness, pH, total iron, residual alum, free residual chlorine and faecal coliforms using standard methods and their values compared with standard local UNBS (2008) and international WHO (2011) drinking water quality guidelines. The results showed that the mean pH of the protected spring below Kikuba Hill (5.21);the AC (Pt/Co) of the borehole below Bweranyangi Junior School (17.28) and the surface well below Nyandozo Primary School (157.58) both situated in Kacuncu as well as the free residual chlorine (mg/L) in tap water at Kanyamabona Trading Centre, Ishaka division (0.192) were below the standard values of WHO (pH, 6.0 - 8.0;free residual chlorine, 0.2 - 0.5) and UNBS (AC, <15). The electrical conductivity, EC (μS/cm) and total hardness (mg/L) of all the selected water sources were within the WHO standards (EC, <1500 (raw water), 0 - 300 (tap water);total hardness, <1500 (raw water), <100 (tap water)). The residual alum (mg/L) in all the tap water sources was also within the WHO guideline (<0.2). On the other hand, the turbidity (27.38 NTUs) and total iron content (0.32 mg/L) of the surface well below Nyandozo Primary School were above WHO guidelines of <15 and <0.3 respectively. Furthermore, the mean faecal coliform counts (CFU/100 ml) in the surface well below Nyandozo Primary School (6.90) and the borehole below Bweranyangi Junior School (16.83) including the surface well below Kyeitembe Trading Centre (9.25) were above the WHO standard faecal coliform count (≤3 TCUs). Only the tap water at Kanyamabona Trading Centre recorded mean faecal coliform counts (0.25 TCUs) beyond the WHO standard (0 TCU). Hence the quality of tap water within the municipality tapped from Nyaruzinga wetland was generally better than the raw drinking water sources (borehole, springs, wells) from the same wetland. Thus the use of piped tap water by the urban inhabitants as opposed to raw water sources needs to be promoted to increase access to safe water.
文摘Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biological properties. This study investigates the suitability of groundwater for domestic and irrigational purposes through physico-chemical and bacteriological analyses in the Northern part of Bamenda Town (Cameroon). Thus, 20 groundwater samples were collected from hand-dug wells and spring sources in September 2018 (rainy season) and February 2019 (dry season) and physico-chemical and bacteriological characteristics were determined. The results revealed that pH ranged from 5.5 to 6.6, thus enabling the classification of the water as slightly acidic. Electrical conductivity varied between 0.01 - 0.06 μS/cm. The relative abundance of ions was such that Ca<sup>2+</sup> > K<sup>+</sup> > Mg<sup>2+</sup> > Na<sup>+</sup> for cations and <span style="white-space:nowrap;">HCO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > Cl<sup>-</sup> > <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub></span> > <span style="white-space:nowrap;">SO<sup>-</sup><sub style="margin-left:-7px;">4</sub></span> for anions. The water types were Ca-Mg-NO<sub>3</sub> in both dry and rainy seasons. The results revealed that the mechanisms controlling groundwater chemistry are rock weathering and atmospheric precipitation. Indicator bacteria such as <em>E. coli</em>, <em>Shigella</em>, <em>Enterobacteria</em>, <em>Vibrio</em>, <em>Streptococcus</em> and <em>Staphylococcus</em> were detected in the studied groundwater samples, thus the water sources may pose a threat to public health.
文摘A preliminary study was conducted to analyze the water quality of spring waters in rural watershed of Western Nepal. 155 spring water samples were collected from Jhimruk, Rangun, Bogtan-Lagam Karnali, Thuligad and Middle Karnali watershed. Collection and analysis occurred twice, once in pre-monsoon 2018 and post-monsoon 2018. Various physical and chemical parameters were analyzed by using standard water quality measurements and compared with the Nepal Drinking Water Quality Standard and the World Health Organization Standard Guideline. The results indicate that the turbidity was high during pre-monsoon season. The highest turbidity of 63.8 NTU was observed in the Bogtan-Lagam Karnali watershed. Two spring sources—one in Bogtan-Lagam Karnali and one in Middle Karnali exceeded the health standard for nitrate-N. The phosphate levels were high during the pre-monsoon season in Jhimruk and Rangun watershed in all the studied sites. Dissolved oxygen levels were relatively high during post-monsoon season. Results of the water quality index in all the studied sites revealed that the water quality ranges from being poor to good conditions in the spring sources. The results from this study suggested that the water bodies are relatively good and can be used for domestic purposes after suitable treatment.
基金supported by the National Natural Science Foundation of China(No.21976169)the Natural Science Foundation of Beijing,China(No.8182055)National Health Commission Fund of China(No.WJW1903)。
文摘The etiology for the high tumor mortality in heavy polluted Yinghe river basin is still unclear and polycyclic aromatic hydrocarbons(PAHs)belong to the priority pollutants in water based on the former surveillance data.In order to explore the potential genotoxicants contributing to the double-endpoint genotoxicity of polluted drinking water source,12 groundwater and 3 surface water samples were collected from 3 villages and the nearby rivers alongside Yinghe river basin,respectively and their comprehensive genotoxicity was estimated with a bioassay group of sOS/umu test and micronucleus(MN)test(MNT).Some groundwater samples showed positive genotoxicity and all surface water samples were highly genotoxic.Eight groundwater samples showed DNA genotoxic effct with the average 4-NQO equivalent concentration(TEQ_(4-NQO))of 0.067μg/L and 0.089μg/L in wet and dry season,respectively.The average MN ratios of groundwater samples were 14.19‰ and 17.52‰ in wet and dry season,respectively.Groundwater samples showed different genotoxic effect among 3 villages.The total PAHs concentrations in all water samples ranged from 8.98 to 25.17 ng/L with an average of 14.97±4.85 ng/L.BaA,CHR,BkF,BaP and DBA were the main carcinogenic PAHs contributing to the genotoxicity of water samples.In conclusion,carcinogenic PAHs are possibly related to the high tumor mortality in the target area.Characterization of carcinogenic PAHs to genotoxicity of drinking water source may shed light on the etiology study for high tumor mortality in Yinghe river basin.Key words:genotoxicity test;drinking water source;high tumor mortality;Yinghe river basin;polycyclic aromatic hydrocarbons(PAHs)
文摘The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source for water supply of Ivan^ice and Rosice towns and provides water for 30,000 inhabitants. The risk analysis was created on the basis of water quality monitoring, hydrogeological assessment and terrain exploration and a revision of protection zones was proposed. The spring area is situated in nitrate vulnerable zones and recently nitrate concentrations have been decreasing. Water quality evaluation results： high concentration of manganese and iron, sometimes higher concentration of ammonium and COD. This area is intensively used for agriculture and it is necessary to make a compromise solution during protection zones proposal, The regime in protection zones can not affect manganese and iron concentration （their origin is in the natural geological environment）. Therefore, water treatment plant is in operation and its modernization is proposed. Furthermore, the paper deals with spring area intensification construction of a new hydrologic borehole, and managed and unmanaged infiltration of surface water. The proposal of protection zones revision consists of reduction to a 2nd level protection zone.
文摘Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have been analyzed in order to provide theoretical bases for prevention and reduction of eutrophication. The analyzed results show that nitrogen forms in the influent area of the reservoir are given priority to ammonia nitrogen and nitrate nitrogen, whose proportion is more than 45% respectively, and this is probably caused by the pollution of inflow water quality;but in the effluent area, the forms are given priority to nitrate nitrogen, whose proportion is as high as 96% and above;also the proportion of ammonia nitrogen drops by more than 80% during the process from the influent area to the effluent area, and this shows that the natural process of nitrification and denitrification can be well accomplished in the reservoir. We recommend here that to reduce the input amount of ammonia nitrogen and organic nitrogen into the reservoir is the most efficient way to prevent or mitigate eutrophication of water body.
