Form Distribution Characteristics of Nitrogen in a Reservoir as Drinking Water Source

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.

Drinking water safety improvement and future challenge of lakes and reservoirs

To meet the Sustainable Development Goal(SDG)target 6.1,China has undertaken significant initiatives to address the uneven distribution of water resources and to enhance water quality.Since 2000,China has invested heavily in the water infrastructure of numerous reservoirs,with a total storage capacity increase of 4.704×1011m3(an increase of 90.8%).These reservoirs have significantly enhanced the available freshwater resources for drinking water.Concurrently,efforts to improve water quality in lakes and reservoirs,facilitated by nationwide water quality monitoring,have been successful.As a result,an increasing lakes and reservoirs are designated as centralized drinking water sources(CDWSs)in China.Among the 3441 CDWSs across all provinces,40.8%are sourced from lakes and reservoirs,32.6%from rivers,and 26.6%from groundwater in 2023.Notably,from 2016 to 2023,the percentage of lakes and reservoirs categorized as CDWSs has increased consistently across all 29 provinces.This progress has enabled561.4 million urban residents to access improved drinking water sources in 2022,compared to 303.4 million in 2004.Our findings underscore the pivotal role of water infrastructure construction and water quality improvement jointly promoting lakes and reservoirs as vital drinking water sources.Nevertheless,the nationwide occurrence of algal blooms has surged by 113.7%from the 2000s to the 2010s,which is a considerable challenge to drinking water safety.Fortunately,algal blooms have been markedly alleviated in past four years.However,it is still crucial to acknowledge that lakes and reservoirs face the challenges of algal blooms,and associated toxic microcystin and odor compounds.

Importance and vulnerability of lakes and reservoirs supporting drinking water in China

Drinking water is closely related to human health,disease and mortality,and contaminated drinking water causes 485,000 deaths from diarrhea each year worldwide.China has been facing increasingly severe water scarcity due to both water shortages and poor water quality.Ensuring safe and clean drinking water is a great challenge and top priority,especially for China with 1.4 billion people.In China,more than 4000 centralized drinking water sources including rivers,lakes and reservoirs,and groundwater have been established to serve urban residents.However,there is little knowledge on the percentage,serving population and water quality of three centralized drinking water source types.We collected nationwide centralized drinking water sources data and serving population data covering 395 prefecture-level and county-level cities and water quality data in the two most populous provinces(Guangdong and Shandong)to examine their contribution and importance.Geographically,the drinking water source types can be classified into three clear regions exhibiting apparent differences in the respective contributions of rivers,lakes and reservoirs,and groundwater.We further found that overall,lakes and reservoirs account for 40.6%of the centralized drinking water sources vs.river(30.8%)and groundwater(28.6%)in China.Lakes and reservoirs are particularly important in the densely populated eastern region,where they are used as drinking water sources by 51.0%of the population(318 million).Moreover,the contribution to the drinking water supply from lakes and reservoirs is increasing due to their better water quality and many cross-regional water transfer projects.These results will be useful for the government to improve and optimize the establishment of centralized drinking water sources,which provide safe and clean drinking water in China to safeguard people's lives and health and realize sustainable development goals.

Eco-environmental vulnerability assessment for large drinking water resource： a case study of Qiandao Lake Area, China

The Qiandao Lake Area （QLA） is of great significance in terms of drinking water supply in East Coast China as well as a nationally renowned tourist attraction. A series of laws and regulations regarding the QLA environment have been enacted and implemented throughout the past decade with the aim of negating the harmful effects associated with expanding urbanization and industrialization. In this research, an assessment framework was developed to analyze the eco-environ- mental vulnerability of the QLA from 1990-2010 by integrating fuzzy analytic hierarchy process （FAHP） and geographical information systems （GIS） in an attempt to gain insights into the status quo of the QLA so as to review and evaluate the effectiveness of the related policies. After processing and analyzing the temporal and spatial variation of eco-environmental vulnerability and major environ- mental issues in the QLA, we found that the state of eco- environmental vulnerability of the QLA was acceptable, though a moderate deterioration was detected during the study period. Furthermore, analysis of the combination of vulnerability and water quality indicated that the water quality showed signs of declination, though the overall status remained satisfactory. It was hence concluded that the collective protection and treatment actions were effective over the study period, whereas immediately stricter measures would be required for protecting the drinking water quality from domestic sewage and industrial wastewater. Finally, the spatial variation of the eco-environmental vulnerability assessment also implied that specifically more targeted measures should be adoptedin respective regions for long-term sustainable develop- ment of the QLA.

Embedded reservoir and constructed wetland for drinking water source protection:Effects on nutrient removal and phytoplankton succession

An embedded reservoir that provides an efficient nutrient removal system protects drinking water.However,embedded reservoirs are rarely used in eutrophic shallow lakes because of their undetermined nutrient retention efficiency and unknown effects by the phytoplankton community.In this study,we aim to investigate the nutrient retention and algae succession in an embedded reservoir and adjacent wetland from April 2017 to September 2018 in the eastern part of Lake Taihu,China.More than 40%of total phosphorus(TP)and 45%of particulate phosphorous entering the reservoir were retained semiannually,and the highest TP removal efficiency was achieved in the reservoir during autumn with an average value of 53.3%±9.9%.The overall nitrogen retention efficiency(21.7%±37.8%)was lower than that of TP(41.8%±27.8%).Similar trends were obtained in the wetland area.An important pathway for phosphorus removal is through particulate matter retention.Our study revealed that nutrient retention mechanisms in the reservoir were primarily via macrophyte absorption,particulate substance sedimentation,and prolonged water residence time.Consequently,the phytoplankton biomass(Chl-a)in the reservoir decreased(from 48.0 to 25.2μg/L)and water transparency improved,due to the decreased P level and transformation of the phytoplankton group into simple structures with good ecological status.Therefore,the combination of embedded reservoir and constructed wetland ecosystem can be used successfully to protect surface water.The results will be advantageous to groups seeking to preserve drinking water sources.

我国城市水源水库水质风险成因及对策

我国城市水源中约40%为湖泊或水库,且大部分为水库,因此水源水库的水质状况对我国城市安全极其关键。本文综述了我国水源水库水质问题研究进展,分析了22个代表性水源水库的周年水质状况。结果发现,当前我国城市水源水库水质风险类型主要是异味问题、藻类水华、铁锰超标、有机质偏高、营养盐超标等。引发水源水库水质问题的主要原因包括流域开发强度过大、库底淤积及内源释放、生态系统结构失衡、气候与水文异常变化等。针对上述主要问题,提出了构建在线水质监测预警体系、控制流域土地开发强度、构建面源拦截及流域净化系统、疏浚底泥、优化生态系统结构、实施应急曝气与控藻工程、完善流域生态保护法律法规等多种水源水库水质安全保障技术措施。鉴于水源水库水质及水生态对暴雨、高温热浪等极端气象响应敏感而复杂,在当前极端天气事件频发、强度不断增加的气候背景下,还应加强水库生态学基础研究,以深入理解水源水库水质对气候变化的响应机制,提高水库水安全保障科技支撑能力,满足我国城市高质量发展的水资源需求。

基于突变理论和模糊数学的湖库型水源地风险评价

为科学评估湖库型水源地风险评价等级,以茂名市电白区罗坑水库水源地为例,从水要素、管理要素、社会经济要素3方面构建了湖库型水源地风险评价指标体系,并确定各指标的评价标准,基于突变理论和模糊数学构建了风险评价模型。结果表明:水源地风险等级与水源地建设投入关系密切。自2018年罗坑水库水源地划为饮用水水源地以来,随着水源地建设投入的加大和保护力度的增强,水源地风险逐渐降低。2018-2022年,罗坑水库水源地风险评价等级依次为较高风险、较高风险、中风险、较低风险、较低风险;尽管现在罗坑水库风险较低,但后续罗坑水库仍需加大投入力度,提高水源地管理、监控和应急水平、进一步降低风险等级。

鄱阳湖流域典型水源水库水华暴发成因及氮污染溯源

富营养化导致的藻类水华是水源地水库面临的主要生态问题之一。探究水源水库中水华暴发成因并开展污染物溯源研究,是预防水华暴发的重要前提。本文选择鄱阳湖流域赣江水系吉安市某典型水源水库为研究对象,通过分析无水华期和水华暴发期水环境特征及其演变规律,探讨了水华暴发的成因及其促发条件,并针对识别出的主要污染因子,开展了同位素溯源研究。结果表明:(1)水库水华暴发的主要原因为水体总氮浓度显著升高(由0.77 mg/L升高至1.57 mg/L),超出了国际公认的水华暴发总氮阈值(0.5~1.2 mg/L),加之夏季高温(32℃)、水库库容量较低,促进了水华暴发;(2)无水华期,水库表层水总氮主要赋存形态为硝酸盐氮(占比>90%),水华暴发期,表层水总氮主要赋存形态由硝酸盐氮转变为有机氮(占比~86%),氮赋存形态转化的主要原因为藻类同化吸收作用;(3)硝酸盐氮、氧同位素示踪结果表明,水库硝酸盐氮主要来源于上游稻田流失的氮肥(负荷贡献率64.45%),其次为上游山区土壤氮流失(14.08%)、大气沉降(12.35%)和农村生活污水(9.12%),因此水库总氮优先控制污染源为上游稻田流失的氮肥。

我国中部地区典型人工水库多环芳烃空间分布特征、来源解析与风险评价

我国中部地区的典型人工水库——漳河水库,是重要的饮用水源地。近年来,随着当地工业化和城市化的发展,尤其是煤矿的开采,多环芳烃(PAHs)的污染可能威胁到饮用水安全。为评估水库中PAHs的污染现状,测定了水体和沉积物中16种优控PAHs的含量,探究了其组成与空间分布特征,解析了其来源,并评估了其生态风险和健康风险。结果表明:水体和沉积物中∑_(16)PAHs的含量(均值±标准差)分别为69.6~509.0 ng/L[(142±89.4)ng/L]和15.9~399.0 ng/g[(205±104)ng/g];水体中以2~3环低分子量PAHs为主,沉积物中以4~6环中高分子量PAHs为主;采用特征比值法和主成分分析-多元线性回归(PCA-MLR)法对PAHs来源进行解析,结果表明低温燃烧源与石油源的混合污染源是漳河水库水体PAHs的主要来源,而沉积物则受到交通排放源与煤炭及生物质燃烧混合污染源的共同影响,这可能与水库周边存在的废弃煤矿以及铁路机场等交通设施有关;漳河水库沉积物中PAHs的潜在生态风险评价结果表明漳河水库除东侧2个点位外,其他点位均不存在PAHs的潜在生态风险;漳河水库水体中PAHs的终生致癌风险(∑ILCRs)结果介于10^(-6)~10^(-4)之间,表明风险水平在可接受范围内。

贵州省黔东南州城市湖库型饮用水源氮磷污染特征及富营养化风险评价

选取贵州省黔东南州18个城市湖库型饮用水源为研究对象,通过枯、丰、平水期的水质开展监测,阐述了黔东南州城市湖库型饮用水源氮、磷的污染特征,并利用综合营养状态指数法对其水体营养化风险进行评价。结果表明,黔东南州城市湖库型饮用水源水体总氮平均浓度为0.76 mg/L,其中硝酸盐占70.0%;总磷平均浓度为未检出,其中可溶性磷酸盐占80.5%。黔东南州城市湖库型饮用水源中氮磷时空分布特征明显,总氮和硝酸盐浓度随水期的变化基本一致,氨氮总体变化不大;总磷和可溶性磷酸盐浓度随水期变化基本一致。利用SPSS Statistics 19.0中的Pearson双侧检验法检验污染因子之间的相关性,枯、丰、平水期仅有COD_(Mn)与Chl-a均呈显著正相关性。利用综合营养状态指数法对黔东南州城市湖库型饮用水源进行评价,枯水期贫营养占66.7%、中营养占33.3%;丰水期贫营养占50.0%、中营养占50.0%;平水期贫营养占38.9%、中营养占61.1%,富营养化风险程度从大到小依次为平水期、丰水期、枯水期,并采用氮磷浓度比(TN/TP)深入分析,得出水源营养盐限制因子主要为磷限制状态,控制磷污染是预防黔东南州湖库水源水体富营养化有效途径。

城市型饮用水水源地“一湖一策”实践与探讨——以董大水库为例

为解决城市型饮用水水源地防洪能力不足、水源保护区水土流失、水资源短缺、面源污染复杂、生物多样性下降、区域执法监管能力不足等问题,以国家大型中心城市饮用水水源地董大水库为例,从防洪安保、水源保护区、水资源、水环境、水生态、执法监管6个方面提出建议和对策措施,以便更好地实施“一湖一策”,改善城市型水源地生态环境,保障城镇居民饮用水安全。

湖库型饮用水水源地水体PAEs变化特征及风险评价

为探究湖库型饮用水水源地水体邻苯二甲酸酯(phthalate esters,PAEs)的季节变化特征和健康风险状况,以玉溪市城区东风水库和飞井海水库水体为研究对象,基于2021~2023年逐月水质监测数据,分析了研究水体PAEs质量浓度水平、季节变化规律及分布特征,并开展了成人和儿童的健康风险评估。结果表明:①2021~2023年,研究水体中邻苯二甲酸二丁酯(dibutyl phthalate,DBP)和邻苯二甲酸二(2-乙基己基)酯(di-2-ethylhexyl phthalate,DEHP)的检出率较高(≥94.4%),其中DBP检出质量浓度的平均值和最大值分别为0.48μg/L和2.91μg/L,DEHP的平均值和最大值分别为1.12μg/L和3.94μg/L,均未超过中国水质卫生标准(GB 5749-2022)和水质量标准(GB 3838-2002)规定限值。②研究水体DBP和DEHP质量浓度的月均值分布具有显著的季节性差异,两者质量浓度大小随季节变化规律具有一致性,均表现为夏、秋两季>春、冬两季,从不同水量期来看,两者质量浓度大小表现为丰水期>枯、平水期,且研究水体中DEHP质量浓度月均值普遍高于同期DBP。③经饮水和皮肤渗入途径,DBP对成人和儿童的最大非致癌健康风险值处于10-3水平,为无风险,而DEHP对成人和儿童的最大致癌健康风险值达到1.57×10^(-6)和2.07×10^(-6)水平,存在潜在致癌健康风险,应予以重视。饮水是致癌和非致癌健康风险的主要暴露途径,须重点关注由其引起的致癌风险。

太湖渔洋山水源地近岸生态修复工程探索

从江苏省苏州太湖渔洋山水源地饮用水水源保护区的实际情况出发,分析水源地现状问题,研究确立水源地近岸生态修复措施,建设风浪削减和蓝藻拦截、鱼贝螺控藻引导水下生态修复工程、水下森林生态修复工程和长效管理等措施,确保饮用水水源地水质达标和长效安全。

太湖流域水库型水源地硅藻水华发生特征及对策分析

基于溧阳市天目湖沙河水库2009—2014年的硅藻群落结构及水质调查,以及宜兴横山水库等硅藻水华期藻类和水质调查数据,分析了太湖流域水库中硅藻水华群落结构特征及受气温、水位、营养盐等环境条件的影响.结果表明,太湖流域硅藻水华的主要发生期为5—7月,快速生长期发生在气温为16-26℃期间,当气温超过26℃时,硅藻的生物量开始下降.硅藻的优势属包括针杆藻、曲壳藻、小环藻和颗粒直链藻.其中沙河水库和横山水库中针杆藻是主要危害,其生物量主导了硅藻总生物量.大溪水库有时以针杆藻为主,有时以颗粒直链藻为主.当总氮浓度低于1.0 mg/L的Ⅲ类水上限时,水体氮浓度能大大限制硅藻生物量,当总磷浓度低于0.025 mg/L的Ⅱ类水上限时,也可能对硅藻生物量产生限制.高于此营养水平,硅藻水华的严重程度主要受气温、降雨等因素影响.研究表明,对于处于中营养水平的太湖流域水库而言,硅藻生物量既受气温、降雨、水位等气象水文条件的控制,又受氮、磷、硅等营养盐供给的影响.硅藻水华的防控既要关注气候和气象条件,也要尽量削减氮、磷营养盐入湖通量,维持较低营养盐水平是确保硅藻水华不形成危害的关键.

湖泊饮用水源地水环境健康风险评价

根据某湖泊饮用水源地水环境质量监测资料,采用美国环境保护署(US EPA)推荐的水环境健康风险评价模型,对2处饮用水源地原水通过饮水途径引起的水环境健康风险进行了评价.结果表明:在2处饮用水源地水环境质量监测项目中,对人体有健康风险的有毒污染物主要是化学致癌物As和Cr(Ⅵ);个人化学致癌物总年风险远大于非致癌物总年风险;2003─2007年2处饮用水源地水环境健康个人总年风险均超过国际辐射防护委员会(ICRP)推荐的标准,主要原因是化学致癌物As和Cr(Ⅵ)的质量浓度过高;因此,加强治理和控制化学致癌物特别是As和Cr(Ⅵ)是降低该湖泊饮用水源地水环境健康风险的有效途径.

安徽省河流和湖库型饮用水水源地水质评价

饮用水水源地的保护问题是关系国计民生的重大问题,饮用水水源地的水质问题越来越受到社会的关注.运用单因子标准指数法以及卡尔森指数法对安徽省境内91个县级以上的饮用水水源地的水质状况以及31个湖库型水源地富营养化程度进行了综合评价,并提出相应的防护措施.结果表明,全省91个饮用水水源地中水质达标的有83个,达标率为91.2%,其中,河流型水源地达标率为93.3%,湖库型水源地达标率为87%,地下水型水源地达标率为87%.

中国地表水环境质量标准研究

《地表水环境质量标准》是水环境管理的尺度,在推动我国水污染防治、公众健康与水生态安全保障等方面发挥着十分重要的作用.随着我国进入生态文明建设新阶段,水环境保护和社会经济发展形势发生深刻变化,如何与时俱进,及时修订丰富现行标准成为迫在眉睫的问题.全面剖析了我国现行GB 3838—2002《地表水环境质量标准》修订历程、修订依据、重要贡献、存在问题及国家需求,结合国际标准发展趋势和我国社会发展阶段,提出未来将《地表水环境质量标准》由单项标准向系列标准转变的修订思路框架.初步阐述了由系列标准构成的“1+N”的标准体系框架,其中,“1”是地表水环境质量基本项目标准,用于判断地表水环境质量的优劣程度,反映水环境功能的基本水质要求;“N”是不同的特定保护项目标准,包括保护水生生物的有毒有害污染物项目水质标准、地表饮用水源地水质标准、湖泊营养物状态评价标准以及地表水水生物状况评价标准,并提出了各分标准的相关制修订方案.

天目湖水体与沉积物中营养盐时空分布及成因

采用现场监测及实验室分析方法,2006年对天目湖水体和沉积物营养盐等进行了调查。结果发现,天目湖水体中营养盐浓度影响最大的是上游流域输入,冬季天目湖上游输入的颗粒物是导致水体营养盐尤其是TN水平升高的主要因素;而在夏季,水体中营养盐以溶解态为主,天目湖的营养类型是磷限制。表层沉积物营养盐含量最高的点位是下游靠近大坝取水口附近,表层沉积物N、P含量明显高于其下各层,尤其对于营养盐含量较高的点位。研究表明,作为一个兼顾饮用水源地和旅游功能的水库,上游区流域综合保护、水库渔业调控及旅游活动的进一步规范是控制天目湖富营养化的关键。

太湖饮用水源地水环境健康风险评价

介绍了水环境健康风险评价方法,并根据太湖饮用水源地水环境质量监测数据,对4个饮用水源地通过饮水途径引起的水环境健康风险进行了评价。结果表明,2005～2009年,4个饮用水源地水环境健康个人年风险多数超过国际辐射防护委员会(ICRP)推荐的标准,主要风险因子为化学致癌物六价铬和砷;化学致癌物对人体健康危害个人年风险度远高于非化学致癌物;化学致癌物所致健康危害的个人年风险呈波动降低变化,非化学致癌物所致健康危害的个人年风险基本保持稳定。

蓝藻水华暴发期间太湖贡湖湾某水厂水源水及出厂水中微囊藻毒素污染分析及健康风险评价

水体富营养化导致的有害蓝藻水华仍是目前全世界普遍面临的水环境问题,而有害蓝藻水华所引起的饮用水安全问题亦受到人们的广泛关注.为了解太湖水源地水源水及自来水厂出厂饮用水中微囊藻毒素(MCs)的污染现状,于2014年8月期间对贡湖湾某水厂水源水及出厂水中浮游植物胞内及胞外MCs浓度进行了调查,并同时检测了相关的理化指标.结果表明,水源水中胞内MCs总浓度平均值为7165.5 ng/L,以MC-LR和MC-RR为主,平均浓度分别为3408.7和3398.8 ng/L,其中MC-RR占总MCs比例的平均值为56.1%;而胞外溶解性MCs浓度相对较低,平均浓度为142.6 ng/L,最高浓度仅为512.8 ng/L.水厂出厂水中胞内MCs的检出浓度(平均值为0.77 ng/L)和检出频率都很低,去除率达99.8%以上;而胞外溶解性MCs的检出浓度(平均值为21.71 ng/L)和检出频率相对较高,但浓度仍远低于国家标准1.0μg/L,其去除率相对较低,仅为62.9%~81.8%.数据分析发现,水源水中胞内与胞外MCs浓度之间呈显著正相关,胞内MCs浓度与总氮(TN)浓度、铵态氮(NH+4-N)浓度、总磷(TP)浓度、高锰酸盐指数(CODMn)和浊度呈显著相关,而胞外MCs浓度与TN浓度、TP浓度、CODMn、浊度和叶绿素a浓度呈显著正相关;逐步回归结果显示,TP对胞内MCs浓度变化的解释率最高,而胞外MCs浓度变化主要与胞内MCs浓度相关.最终,通过对出厂饮用水中MCs浓度非致癌风险指数的计算发现,出厂饮用水对人类健康的威胁较小,但致癌风险相对较高.