6种重金属对赤子爱胜蚓的急性毒性效应与风险评价

Acute toxicological effects and risk assessment of six heavy metals on the earthworm,Eisenia foetida

【背景】近年来,土壤重金属污染问题日益凸显,对生态环境、食品安全和人体健康构成了严重威胁,其急性毒性尚未明确。【方法】采用滤纸接触法和人工土壤法测定了铜(Cu2+)、锌(Zn2+)、镍(Ni+)、镉(Cd2+)、铅(Pb2+)和锰(Mn2+)等6种重金属对赤子爱胜蚓的急性毒性效应,并参照欧盟指令91/414/EEC标准评价了其环境风险。【结果】滤纸接触法48h测定结果表明,6种重金属对蚯蚓的LC50为3.17(2.53～3.81)～90.42(69.45～140.47)μg.cm-2,其毒性次序为Cu2+>Zn2+>Ni+>Cd2+>Pb2+>Mn2+。人工土壤法14d测定结果表明,6种重金属对蚯蚓的LC50为1347(1236～1453)～6936(6144～8930)mg.kg-1,其毒性次序为Cu2+>Cd2+>Ni+>Zn2+>Mn2+>Pb2+。风险评价结果显示,Cu2+、Zn2+、Ni+、Cd2+、Pb2+和Mn2+等6种重金属的暴露比(toxicity/exposureratio,TER)分别为3.37、4.46、8.68、1428、13.87和5.85。【结论与意义】6种重金属对土壤动物蚯蚓均具有潜在的毒性效应。Cu2+、Zn2+、Ni+、Mn2+等4种重金属对赤子爱胜蚓存在急性毒性风险,而Cd2+和Pb2+对赤子爱胜蚓的急性毒性风险水平是可接受的。该评价结果可为我国制定基于风险的土壤环境质量标准提供依据。

[ Background] The problem of heavy metal contamination in soil is recoganised as a especially serious threat to the envi- ronment, food safety and human health. Acute toxicity data are not available for all heavy metals. [ Method ] The acute toxicity effects of copper （ Cu2＋ ）, zinc （ Zn2＋） , nickel （ Ni＋ ）, cadmium （ Cd2＋）, lead （ Pb2＋ ） and manganese （ Mn2＋ ） to the earth- worm, Eisenia foetida Savigny, were determined by using the filter paper contact method and the artificial soil method. The environ- mental risk was assessed according to the Directive 91/414/EEC of the European Community. [ Result] The results of filter paper contact method at 48 h showed that the LCso values of 6 heavy metals to E.foetida, were in the range of 3.17 （2.53 - 3.81 ） -90.42 （69.45 - 140.47） μg cm -2, and the toxicity order was Cu2 ＋ 〉 Zn2＋ 〉 Ni＋ 〉 Cd2＋ 〉 Pb2＋ 〉 Mn2＋. When using the artificial soil method, after 14 d exposure, the acute toxicity of 6 heavy metals to E.foetida （LCso） was 1347 （1236 -1453 ） - 6936 （6144 - 8930） mg kg-1, and the toxicity order of the six metals was Cu2＋ 〉Cd2＋〉 Ni＋〉Zn2＋ 〉Mn2＋ 〉Pb2＋. The toxicity/exposure ratio （TER） of Cu2＋, Zn2＋, Ni＋, Cd2＋, Pb2＋ and Mn2＋ were 3.37, 4.46, 8.68, 1428, 13.87 and 5.85, respectively. [Conclu- sion and significance ] All 6 heavy metals had potential toxic effects on the earthworm. Based on the environmental quality standard for soils of China, the data of environmental risk assessment showed Cu2＋ , Zn2＋ , Ni＋ and Mn2＋had potential acute risk to E. foeti- da, and the acute risk of Cd2＋ and Pb2＋ were acceptable. The results may provide useful reference information for China to develop risk-based environmental quality standard for soils.