中文摘要：

为研究长湖水库沉积物重金属污染状况及其对水体环境和生物的潜在影响，2015年6月采集了水库表层（0~10cm）沉积物，分析了沉积物中Cu、Zn、Pb、Cd、Cr和Ni重金属的含量及赋存形态，结合潜在生态风险指数、地积累指数评价结果和重金属化学形态特征，选取Cu、Zn、Cd进行了温度、盐度和pH三因子控制下的单因素和正交释放试验。结果表明，水库表层沉积物样品中Cu、Zn、Pb、Cd、Cr和Ni重金属的平均含量分别为312.99、520.33、204.74、3.17、57.35和27.06mg?kg-1，其中，Cd、Cu、Zn和Pb含量显著超过广东省土壤元素背景值，分别是背景值的56.60、18.41、11.00和5.69倍，Cd的富集效应最明显。Cr和Ni为低污染水平，Zn、Pb和Cu为中-重度污染水平，Cd达到极严重污染水平；Cd的污染贡献率极高，沉积物重金属的潜在生态风险达到了极高水平。Cu、Zn、Pb、Cd、Cr和Ni的弱酸溶解态所占比例均低于0.10%，但生物有效态含量分别占总量的68.06%、54.61%、45.51%、18.55%、30.05%和29.13%；Zn和Cu的含量达到了中-重度污染水平，较高的生物有效态含量可能对生物产生较大潜在危害。沉积物样品中Cu、Zn、Cd的释放量随着上覆水温度、盐度的升高及pH的降低而增大，Cd的释放受温度和pH的影响较低；3种因子对Cu和Cd释放量的影响显著性表现为盐度>温度>pH，对Zn释放量的影响显著性表现为盐度>pH>温度。本研究结果可为长湖水库重金属污染防治提供科学依据。

英文摘要：

To investigate the heavy metal pollution in Changhu Reservoir sediment and its potential impacts on the overlying waterand organisms,a sample of0~10cm surface sediment was collected from the reservoir in June2015and analyzed to determine thetotal contents and chemical speciations of Cu,Zn,Pb,Cd,Cr and Ni.Monofactorial and orthogonal experiments under differenttemperature,salinity and pH conditions of the overlying water were conducted to examine the release mechanisms of Cu,Zn and Cdfrom sediment.The potential ecological risk index,the geoaccumulation index and the geochemical speciations extracted from theBCR procedure were used to assess the potential effects of heavy metal release on the aquatic ecological condition in ChanghuReservoir.The results showed that the average content of Cu,Zn,Pb,Cd,Cr and Ni in surface sediment was312.99,520.33,204.74,3.17,57.35and27.06mg?kg-1,respectively.The content of Cd,Cu,Zn and Pb was56.60,18.41,11.00and5.69times as high astheir corresponding local soil background values,respectively,and the enrichment effect of Cd was most obvious.The content of Crand Ni was at low pollution level,and Zn,Pb and Cu was at medium-high pollution level.In contrast,Cd was found to be a severepollutant.Sediment pollution caused by heavy metals,especially due to the high contribution rate of Cd pollution,resulted in theextremely high level of potential ecological risk.The proportion of dissolved weak acids in all heavy metals was less than0.10.Bioavailable fraction of Cu,Zn,Pb,Cd,Cr and Ni accounted for68.06%,54.61%,45.51%,18.55%,30.05%and29.13%of the totalcontents,respectively,exhibiting a higher bioavailability and medium-high pollution level of Cu and Zn,and thus likely imposinggreater hazards on aquatic organisms.The release amount of Cu,Zn and Cd from sediment increased with increasing watertemperature and salinity,but decreasing pH value.Nevertheless,water temperature and pH exerted little effects on the releasingbehavior of Cd.Water salinity,temperature and pH was ranked as the first,second