底泥疏浚对湖泊沉积物的生态毒性效应的影响

Influence of sediment dredging on the ecotoxic effect of lake sediments

采用淡水沉积物质量基准和微生物毒性试验方法，对疏浚前后五里湖沉积物提取液和全底泥沉积物的生态毒性进行了研究与分析，结果表明，疏浚后，沉积物中各重金属污染物的总体含量均显著降低，但是铬、铅和镍的含量仍然分布在阈值效应低值（TEL）和可能效应水平值（PEL）之间的灰色区域，仍可能对水体生态系统产生不良影响；疏浚后1个月，沉积物提取液中发光菌发光试验的EC50值降低约50％，毒性增加近1倍；与疏浚前相比，全底泥沉积物的细菌毒性试验的EC50值降低11％-30％；全底泥月芽藻毒性试验的EC50值也有显著降低。

The ecotoxicity of the extracted liquor and whole sediment in Wulihu Lake before and after dredging were studied and analyzed, adopting the freshwater sedimont quality guidelines and the microbial toxicity test technique. The total content of each heavy metal pollutant in sediment was all reduced after dredging; but the contents of chromium, lead and nickel still distributed in the grey area between the threshold effect low value （TEL） and the possible effect level value （PEL）; and still would produce bad effect on waters ecosystem; the EC50 value of luminescences test in the sediment extracted liquor was reduced about 50% at one month after dredging; toxicity increased near one time; the EC50 values of the whole sediment bacteria toxicity test were reduced I 1%-30% compared with these before dredging; and there were also marked decrease of EC50 value of the toxicity test of the whole sediment crescent algae.