基于平衡分配法的太湖沉积物重金属质量基准及其在生态风险评价中的应用研究

水体沉积物评价和管理中最紧迫的问题是建立水体沉积物质量基准以保护水生生物.以太湖为研究对象,利用平衡分配法初步探讨了太湖不同湖区中Pb、Cu、Zn、Cr4种重金属的质量基准,分析了各校正项对不同重金属基准的贡献,利用基于沉积物质量基准的SQG-Q法对太湖各湖区沉积物重金属的潜在生态风险进行了评估.结果表明：SQGPb、SQGCu、SQGZn和SQGCr分别为21.2～307.4mg·kg-1、52.3～281.0mg·kg-1、399.7～1659.1mg·kg-1和21.2～68.7mg·kg-1,不同湖区沉积物重金属质量基准存在差异;SQGPb基本由AVS校正决定,Kp·WQC值和粒径校正两者主要决定了SQGCu和SQGZn,SQGCr则由Kp·WQC值、粒径校正、残渣态校正共同决定;四种重金属含量与沉积物质量基准初步值相比,超基准程度次序为Cr〉Pb〉Zn〉Cu;太湖各湖区沉积物中的重金属存在中等潜在生态风险,且大小顺序为竺山湾〉梅梁湾〉贡湖湾〉东太湖〉西部沿岸区和东部沿岸区〉湖心区〉南部沿岸区.

Sediment quality guidelines and potential ecological risk assessment for heavy metals based on equilibrium partitioning approach in Taihu Lake

The development of sediment quality guidelines (SQGs) is one of the challenges for protection of aquatic biodiversity. We applied Equilibrium Partitioning Approach to preliminarily derive the sediment quality guidelines for heavy metals such as lead, copper, zinc and chromium in different regions of Taihu Lake, and analyzed the contributions of the normalization factors to SQGs. Potential ecological risk assessment of the heavy metals in sediments based on SQG-Q method was also conducted. The calculated SQGs of lead, copper, zinc and chromium in different regions of Taihu Lake were, respectively, 21.2~307.4 mg·kg^-1, 52.3~281.0 mg·kg^-1, 399.7~1659.1 mg·kg^-1 and 21.2~68.7 mg·kg^-1. For SQG_Pb, the AVS was the most important normalization factor, for SQG_Cu and SQG_Zn, the K_p·WQC and fine material were the most important, while SQG_Cr was determined by K_p·WQC, fine material and residual. Comparing to the calculated SQGs, the exceeding extent of heavy metals followed an order of Cr>Pb>Zn>Cu. This suggested that there existed "moderate level" ecological risks for heavy metals in the sediments of Taihu Lake, and the potential ecological risks decreased in the order of Zhushan Bay>Meiliang Bay>Gonghu Bay>Eastern Taihu Lake>Eastern Coastal Area, Western Coastal Area>Middle Area>Southern Coastal Area.