淀山湖沉积物重金属分布特征及其与底栖动物的关系

The distribution of heavy metals in surface sediment of Lake Dianshan and its correlations with macrozoobenthos

采用X-ray荧光光谱法测定了淀山湖沉积物中17种重金属元素的含量,分析了各元素的空间分布特征,并采用Hkanson潜在生态风险指数法评价了Cd、As、Pb、Cu、Cr、Zn6种重金属的潜在生态风险.结果表明:沉积物中重金属含量大小顺序为:Al>Fe>K>Na>Ca>Mg>Ti>Mn>Zr>Zn>Sr>Rb>Cu>Cr>Pb>Ni>As;沉积物中重金属的潜在生态风险处于中度风险水平;各重金属元素的单项潜在生态风险大小顺序为:Cu>As>Pb>Ni>Cr>Zn.同时,对淀山湖大型底栖动物的群落结构和多样性进行了调查分析,并对重金属元素之间及其与底栖动物分布特征之间的相关性进行了探讨.结果发现,除Cr外,Pb、Zn、Cu、Ni、As相互之间都存在显著相关性(p<0.01);寡毛类动物密度与Zn、Cu含量、重金属综合污染指数Cd、重金属潜在生态风险指数RI呈显著正相关关系(p<0.01);Shannon-Wiener指数(H)、Margalef指数(d)与Pb、Ni含量呈显著负相关关系(p<0.01).

In the present study,the contents of seventeen heavy metals were determined using X-ray fluorescence spectrometry in Lake Dianshan sediments and their spatial distribution characters were analyzed.Hkanson＇s methodology was applied to determine the degree of contamination and the ecological risk of six heavy metals：Cd,As,Pb,Cu,Cr and Zn.The results showed that according to the contents,these heavy metals in the surface sediments followed the order as Al Fe K Na Ca Mg Ti Mn Zr Zn Sr Rb Cu Cr Pb Ni As.The potential ecological risk index showed that the heavy metals pollution risk was moderate in the Lake Dianshan sediments.According to the impact extent of the potential ecological risk,the pollutants could be ranged as Cu As Pb Ni Cr Zn.The community structure and biodiversity of macrozoobenthos were investigated and additionally the correlations among the heavy metals and macrozoobenthos were analyzed.The results showed that except for Cr,there were highly significant positive correlations between the contents of the heavy metals.The contents of Cu,Zn and the potential ecological risk indexes of Cd,RI were highly correlated to the density of Oligochaete.Shannon-Wiener index and Margalef index had highly negative correlations with the contents of Pb and Ni.