电子垃圾拆解地重金属污染对稻田土壤线虫群落结构的影响

Effects of Heavy Metal Contamination on Nematode Communities in Paddy Soils of an E-waste Recycling Area

为了解电子垃圾污染区重金属对土壤线虫群落结构的影响,采集了广东贵屿镇8块稻田的土壤样品,用ICP-MS分析重金属含量,并用淘洗-过筛-蔗糖离心漂浮法分离线虫。结果表明:75%的稻田土壤样品不同程度地受到Cu、Pb、Cd、Zn的污染,其中Cu、Pb、Zn的浓度呈显著正相关(P<0.05);分离出的线虫隶属于6目19科26属,植物寄生线虫占主要比例,潜根属、螺旋属为常见属;植物寄生线虫的丰度随着Cu含量的增加而显著降低(P<0.05),其成熟指数亦受到Pb的显著抑制(P<0.05)。与未受重金属污染的样本相比,线虫数量在轻微污染稻田中略有增加,而在其他样本中会随着污染程度的增加而显著下降。此外,受电子垃圾重金属污染的土壤中主要是c-p2类群(r-策略者)和c-p3类群线虫(k-策略者),其中c-p2类群的比例随着污染程度的增加而增加,而c-p3类群却与之相反,即不同类群线虫对重金属污染的反应特性不同。分析结果显示,在电子垃圾重金属污染情况下,土壤线虫的数量及种群结构产生了一定响应,可作为评价电子垃圾重金属污染的生物指标。

In order to investigate the influence of heavy metal contamination on nematode community structure in paddy-field polluted by electronic waste(e- waste), soil samples were collected from eight typical rice fields in e- waste recycling area of Guiyu Guangdong Province. The contents of heavy metals(Cd, Cu, Pb, Zn)were determined by ICP-MS, and nematodes were separated by elutriation-siftingsugar solution centrifugation method and then identified. The results showed that 75% paddy-field samples were contaminated by Cd, Cu,Pb, Zn, and significant positive correlations(P<0.05)were observed among Cu, Pb, Zn. Nematodes belonged to six orders, 19 families and 26 genera. The plant parasitic nematodes were dominant, and Hirschmanniella, Helicotylenchus were common dominant genera. With increasing Cu in soil, ratio of plant parasitic nematodes to total nematodes dropped significantly. There was negative correlation between Pb con-centrations and the plant-parasites maturation index(P<0.05). Compared with the unpolluted fields, amount of nematodes in paddy fields with low-grade pollution increased slightly, whereas that in the other fields dropped significantly with the increase of pollution grades. The nematode types of c-p2(r-strategists)and c-p3(k-strategists)were dominant in soils contaminated by heavy metals from e-wastes. With the increase of pollution levels, the proportion of c-p2 increased, but c-p3 groups showed an opposite trend. These results indicate that the number of nematodes and its function structure respond to heavy metal contaminations, and could be served as an important indicator to evaluate the heavy metal contaminations in e-waste recycling areas.