地下水中潜在危害有机物识别与筛选方法

Identification and screening of potential hazards organic pollutants in groundwater

针对地下水中频繁检出的各类有机物,运用理论方法定量计算污染物对地下水的危害系数,对有机物的污染调查、地下水污染防治具有一定的指导意义。为研究有机物对地下水的危害性,汇总了535项有机物,目前这些指标在国内外水质标准中均没给出标准值。从有机物的自身属性入手,假定所有物质处于相同的外界环境中,经过包气带吸附、降解、挥发等作用,分析其进入地下水的难易程度。利用美国环保局的软件EPI Suit4.10,获取了指标的有机碳吸附系数(K_(oc))、半衰期(DT_(50))和亨利常数(K_H),并结合毒性参数基于健康的评价基准值,构建了污染物潜在危害参数体系。运用3种方法计算有机物的危害系数H、污染指数G和衰减系数K,对比3种计算结果,筛选出100项潜在危害有机物。分析表明,所筛选出的100项指标毒性较大、难挥发,并且有机物的K_(oc)对污染指数(G)和衰减系数(K)的贡献比DT_(50)、K_H更大。

The theoretical study of organic pollutant hazard factors by quantitative calculation is useful when attempting to prevent and control groundwater pollution. A total of 535 kinds of organic matters,which have no reference water standards at home or abroad,were summarized so that the harmfulness of organic pollutants in groundwater could be investigated. According to the characteristics of these pollutants,and assuming all the pollutants were subjected to the same outside ambient conditions,the extent to which these pollutants got into the groundwater through the processes of adsorption,degradation,volatilization,and other effects in the vadose zone was analyzed. The organic carbon adsorption coefficient（ K_（oc））,half-life（ DT_（50））,and Henry constant（ K_H） of the pollutants were obtained by EPI Suit（ V4. 10）,which was developed by the United States Environment Protection Agency. The potential hazard parameters of the pollutants were established by combining with health-based screening levels of the toxic parameters. Hazard factors,groundwater ubiquity scores,and attenuation factors were calculated by three methods,and 100 potential hazardous organic pollutants were selected by comparing these three calculation results. The results showed that the selected contaminants were very toxic and were difficult to volatilize. Furthermore,Koccontributed more to the groundwater pollution index（ G） and attenuation factor（ K） than DT_（50） and K_H.