上海市闵行区居民供水系统中挥发性有机物分析

 目的   调查上海市闵行区以黄浦江和青草沙水库为水源的居民供水系统中挥发性有机物(volatile organic compound,VOC)的污染状况。方法    于2016年2月(枯水期)和8月(丰水期),采集为闵行区居民供水的黄浦江和青草沙水库水源水、出厂水及末梢水样品共126份,使用吹扫捕集-气相色谱-质谱联用法对86种VOC进行定性和定量测定。 结果    以黄浦江和青草沙为水源的供水系统检出VOC分别为32种和28种,属于美国环境保护署(EPA)优先控制污染物的分别为19种和21种,有中国国家卫生标准限值要求的分别为18种和14种。检出物含量分别在0.04～213 μg/L和0.04～728 μg/L范围内;黄浦江水源除甲基叔丁基醚外,其他均处于较低浓度水平,青草沙水源除部分样本中二氯甲烷和1,2 二氯乙烷超过卫生标准限值以外,其他有限值要求污染物均未超过限值,检出物质以一氯甲烷和甲基叔丁基醚浓度最高。两个供水系统中VOC均以卤代脂肪烃和芳香族化合物为主,但包含的化合物种类、数量却各有不同;卤代脂肪烃在两者检出的VOC中分别占37.5%和56.2%,芳香族化合物分别占64.3%和28.6%。两个供水系统均检出相同的5种消毒副产物(disinfection by product,DBP),除三溴甲烷外,二氯甲烷、三氯甲烷、一溴二氯甲烷、二溴一氯甲烷在青草沙供水系统中浓度显著高于黄浦江供水系统;除二氯甲烷外,其他物质浓度变化均为末梢水>出厂水>水源水。结论    闵行区两个供水系统水源水、出厂水和末梢水中均存在VOC污染,且污染特征不同,部分不在国家卫生标准范围内的VOC检出污染物应当在今后水质监测中引起足够重视。

Analysis of volatile organic compounds in water supply system of Minhang District of Shanghai

Objective    To investigate the pollution status of volatile organic compounds (VOCs) in water supply systems of Minhang District of Shanghai taking Huangpu River and Qingcaosha reservoir as water source.Methods    A total of 126 water samples were collected from water supply system for residents in Minhang District in Feb.(dry season) and Aug.(wet season) of 2016,including source water from Huangpu River and Qingcaosha reservoir,the factory finished water and tap water.Purge and trap gas chromatography mass spectrometry was used for the qualitative and quantitative determination of 86 kinds of VOCs.Results    Totally,32 and 28 kinds of VOCs were detected in the water supply systems from the Huangpu River and Qingcaosha reservoir,among which19 and 21 pollutants were priority-controlled by the US EPA,and 18 and 14 species have the national standard in China separately.The concentration of detected pollutants ranged from 0.04 μg/L to 213 μg/L and from 0.04 μg/L to 728 μg/L,respectively.The pollutants in the supply system of the Huangpu river were at the lower level except for methyl tert-butyl ether (MTBE).The pollutants in the supply system of Qingcaosha reservoir were lower than the national standards in addition to dichloromethane and 1,2-dichloroethane,and with the higher level of Methyl chloride and MTBE.In both water supply systems,halogenated aliphatic hydrocarbons and aromatic compounds were mainly types of VOCs,but there were varied types and quantities of compounds in each water supply system.The halogenated aliphatic hydrocarbons accounted for 37.5% and 56.2% of the detected VOCs respectively,while aromatic compounds accounted for 64.3% and 28.6%.A total of 5 disinfection by products (DBP) were detected in both water supply systems,but the concentrations of dichloromethane,chloroform,bromodichloromethane and dibromochloromethane in the Qingcaosha reservoir water supply system were significantly higher than those in the Huangpu River water supply system,except for bromoform.The concentration of the disinfection by products in order from large to small were in the tap water,factory finished water and source water,while dichloromethane was an exception.Conclusions    There were VOC pollutions in both water supply system in Minhang District,including source water,factory finished water and tap water,with different pollution characteristics.Adequate attention should be paid to the pollutants without national standards in the future water quality monitoring work.