应用相平衡分配法建立污染物的沉积物质量基准

Application of Equilibrium Partitioning Approach to Derive Sediment Quality Criteria for Heavy Metals

以污染较为严重的天津某污水库的表层沉积物为对象,应用热力学相平衡分配(EqP)法,初步探讨了该水体沉积物中4种重金属(Cd,Cu,As,Hg)和2种有机氯农药〔滴滴涕(DDT)、六六六(HCH)〕的沉积物质量基准(SQC)推荐值.其中,基于我国地表水水质基准的4种重金属Cd,Cu,As和Hg的SQC推荐值分别为4.3,86,218和0.45 mg/kg;基于美国环境保护署(US EPA)的保护水生生物水质基准的2种有机氯农药(DDT和HCH)的SQC推荐值分别为18.0和0.27μg/kg.通过与不同国家制订的SQC值进行比较发现,地区间的SQC值相差较大,说明在SQC值的确定过程中存在诸多不确定因素.所推算出的几种污染物的SQC值均接近所有数据的中间值,表明其可为该水体沉积物的风险评估提供依据.

An Equilibrium Partitioning （EqP） approach was used to derive the sediment quality criteria （SQC） values for heavy metals such as cadmium （Cd）, copper （Cu）, arsenic （As）, mercury （Hg） and two organic chlorine pesticides （DDT, HCH） in a sewage reservoir located in Tianjin. The reservoir had long received waste water discharged from nearby chemical plants and was heavily polluted. SQCs of heavy metals were based on the surface water quality standard of China. The SQC values of Cd, Cu, As, Hg were 4.3, 86, 218, and 0.45 mg/kg respectively. SQC values for organic chlorine pesticides were based on US EPA＇s water quality standard, which is used for protecting aquatic organisms. The SQC values of DDT and HCH were 18.0 and 0.27 μg/kg respectively. SQCs from different countries were compared and it was found that SQCs varied a lot in different regions, suggesting that SQCs were affected by many factors. It was found that the SQC values obtained in this study were close to the middle values of the referenced data, which showed that the SQC values obtained in this study can provide a basis for future environmental risk assessment.