长江中游典型湖泊沉积物重金属分布特征、生态风险评估及溯源

集中采集洞庭湖、洪湖和赤湖表层沉积物样品并检测其中10种重金属含量，使用地理信息系统表征空间分布，利用地累积污染指数法（I_geo）、富集因子法（EF）和潜在生态风险指数法（RI）协同评估重金属积累的潜在风险，并利用相关性分析（Pearson）和主成分分析（PCA）溯源.结果表明，Cd元素的污染状况和潜在生态风险最为严重，东洞庭湖、洪湖和赤湖中ω（Cd）的平均值分别为2.85、1.59和3.57 mg·kg^-1，分别是对应省份土壤背景值的25.87、11.36和37.58倍，均超出风险筛选值（0.6 mg·kg^-1），其中赤湖超出风险管制值（3.0 mg·kg^-1）.除Cd外，洪湖中的As值得关注，赤湖中的Cu、As、Zn和Pb都不容忽视.三湖的潜在生态风险排序为：赤湖（RI=1 127）>东洞庭湖（RI=831）>洪湖（RI=421）.重金属来源主要是工矿业冶采、农业生产和水产养殖等，部分重金属（Mn和Cu）为自然源.研究对长江中游典型湖泊沉积物重金属防控具有重要意义.

Distribution Characteristics, Ecological Risk Assessment, and Source Tracing of Heavy Metals in the Sediments of Typical Lakes in the Middle Reaches of the Yangtze River

In this study, surface sediment samples were collected from Dongting Lake, Honghu Lake, and Chihu Lake, and the concentrations of 10 heavy metals were measured. Then, the potential risk of heavy metal accumulation was evaluated using the cumulative pollution index (I_geo), the enrichment factor (EF), and the potential ecological risk index (RI), and the sources were traced using correlation analysis (Pearson) and principal component analysis (PCA). The results showed that the pollution and potential ecological risk of Cd were the most serious. The mean values of Cd in East Dongting Lake, Honghu Lake, and Chihu Lake were 2.85, 1.59, and 3.57 mg·kg^-1, respectively. The concentrations of Cd were 25.87, 11.36, and 37.58 times higher than the soil background values of the corresponding provinces, which exceeded the risk screening value (0.6 mg·kg^-1). Particularly, the Cd concentration of Chihu Lake exceeded the risk control value (3.0 mg·kg^-1). Besides Cd, the concentration of As in Honghu Lake was also of concern. At the same time, the Cu, As, Zn, and Pb in Chihu Lake should not be neglected. The potential ecological risks of the three lakes were ranked as follows:Chihu Lake (RI=1 127)>East Dongting Lake (RI=831)>Honghu Lake (RI=421). The primary sources of heavy metals were industrial mining, agricultural production, and aquaculture, and some heavy metals (Mn and Cu) were from natural sources. This study was of great significance for the prevention and control of heavy metals in the sediments of typical lakes in the middle reaches of the Yangtze River.