应用物种敏感性分布评估DDT和林丹对淡水生物的生态风险

介绍了利用物种敏感性分布（SSD）进行生态风险评价的原理与步骤，构建了淡水生物对DDT和林丹的物种敏感性分布.在此基础上，计算了DDT和林丹对不同类别生物的HC5(Hazardous Concentration for 5% the species)阈值，预测了不同浓度DDT和林丹对生物可能造成的危害，并比较了不同类别生物对DDT和林丹的敏感性，以及DDT和林丹对淡水生物的生态风险.结果表明，DDT和林丹对淡水生物的HC5值分别为1.70μg·L-1和5.96μg·L-1 ，DDT对生态系统的危害大于林丹.当DDT或林丹的浓度为5μg·L-1时，对生态系统仅有轻微影响，而当DDT或林丹的浓度为500μg·L-1时，将有81.5%的物种受到DDT的危害，或有68.1%的物种受到林丹的危害.不同类别生物对DDT的敏感性从甲壳类、昆虫和蜘蛛类到鱼类依次降低，对林丹的敏感性大小依次为昆虫和蜘蛛类、甲壳类、鱼类.与林丹相比，DDT对淡水脊椎动物与无脊椎动物以及甲壳类和鱼类的生态风险较大，而对昆虫和蜘蛛类，林丹与DDT的生态风险差别不大.

Assessing ecological risks of DDT and lindane to freshwater organisms by species sensitivity distributions

The paper presents the principles and steps of ecological risk assessment by means of species sensitivity distributions ( SSD ) . Such a framework has been applied to the SSD of different freshwater organisms exposed to DDT and lindane. Based on this, the hazardous concentrations for 5% of the species ( HC5) of DDT and lindane to freshwater organisms were estimated and the potential affected fractions ( PAF) of various DDT and lindane concentrations to freshwater organisms were also predicted. The sensitivity of different freshwater species to DDT and lindane are compared to the ecological risks of DDT and lindane to various freshwater organisms. The results show that HCS values of DDT and lindane to freshwater organisms are 1. 70 μg· L~(-1) and 5. 96 μg · L~(-1), respectively, indicating that DDT was relatively more harmful to freshwater organisms. For both DDT and lindane there were minimal impacts to freshwater organisms at a concentration of 5 μg·L~(-1) ; however, at 500μg· L~(-1) , 81. 5% and 68.1% of freshwater organisms were impacted by DDT and lindane, respectively. The sensitivity of various freshwater organisms to DDT was in the order crustaceans > insects and spiders > fishes, whereas for lindane, the effects was in the order insects and spiders > crustaceans > fishes. Compared with lindane, DDT posed higher ecological risks to freshwater vertebrates and invertebrates as well as crustaceans and fishes; however, little differences were found between DDT and lindane in the ecological risks posed to freshwater insects and spiders.