珠海养殖池塘沉积物中BHC和DDT残留与风险分析

Residue characteristics and risk evaluation of BHC and DDT in sediments of culture ponds in Zhuhai

测定了珠海水产养殖池塘沉积物中六六六(BHC)和滴滴涕(DDT)残留量。结果显示,ΣBHC、ΣDDT残留量(湿重)分别为0.36～1.67、0.95～2.59μg·kg^(-1),平均分别为0.91、1.81μg·kg^(-1),明显低于一些江河、湖泊、海湾沉积物中的含量,符合我国无公害水产品产地沉积环境质量标准。γ-BHC/ΣBHC 比值为0～21.6%,(DDE+DDD)/ΣDDT 比值为61.1%～76.7%,表明珠海池塘养殖环境中的 BHC 日趋减少,推测残留的DDT 大部分已降解为 DDE 和 DDD,近年没有 BHC 和 DDT 输入。BHC 和 DDT 含量低于 ERL 值,表明 BHC 和DDT 残留对珠海池塘养殖基地造成的生态风险极低。

The benzene hexachlorides （BHCs） and dichloradiphenyl trichloroethanes （DDTs） in sediments of some aquaculture ponds in Zhuhai, China were determined in July, 2005. The results showed that the contents of total BHC and total DDT were from 0. 36 to 1.67 （ arithmetic mean =0.91 ） μg·kg^-1 and 0. 95 to 2. 59 （ 1.81 ） μg·kg^-1, respectively. The residue levels of ∑BHC, ∑DDT in sediments of the tested area were lower than those of some rivers, lakes and bays, and also under the superior limits of national sediment quality standard for no contamination fishery products. The quality grade of BHCs or DDTs was ＂basically clean＂ . The ratio of γ-BHC/∑BHC, （DDE ＋ DDD）/∑DDT were from 0 to 21.6% and 61.1% to 76. 7%, respectively. It may be guessed that BHCs gradually decreased, most residual DDT had decomposed to DDE and DDD, there was little or no BHCs or DDTs distributed into the sediments of Zhuhai aquaculture ponds in recent years. The contents of BHC and DDT were lower than the ERL value of risk evaluation to consumers of bottom feeders.