Anhui Key Laboratory of Freshwater Aquaculture and Enhancement, Institute of Fisheries Research, Anhui Academy of Agricultural Sciences, Hefei 230001, China.
Anhui Key Laboratory of Nutrient Recycling, Resources and Environment, Institute of Soil and Fertilizer, Anhui Academy of Agricultural Sciences, Hefei 230001,China.
Sci Total Environ. 2022 Nov 25;849:157862. doi: 10.1016/j.scitotenv.2022.157862. Epub 2022 Aug 5.
Bioavailability-based probabilistic risk assessment is an effective approach for risk characterization of trace metals towards aquatic species. However, it has not been routinely applied in lake management due to limited research. In this study, Chaohu Lake (Anhui Province, China) was selected as a case study, and total and bioavailable concentrations of trace metals in surface sediment were investigated using chemical extraction and diffusive gradients in thin films (DGT). Probabilistic risk assessment (PRA) was performed using Monte Carlo simulation. In addition, the species sensitivity distribution (SSD) was constructed using acute toxicity data to model the sensitivity of aquatic species towards metals. Three evaluation methods, namely, toxic units based on total content, modified potential ecological risk index (RI) based on chemical fractionation and DGT-SSD coupled PRA, were implemented and compared. Results showed that trace metals, especially Cd, were significantly affected by anthropogenic activities. Chemical fractionation analysis revealed that the majority of Cd was readily available to aquatic organisms, while Cr was stable under normal conditions. Toxic units based on the total content demonstrated that metals in sediment were at 91.6 % low and 8.4 % medium toxicity levels, while the modified RI based on chemical fractionation found toxicity levels of 84.1 % low and 15.9 % medium. Furthermore, the combined toxicity calculated from DGT-SSD coupled PRA showed that trace metals in sediment had a 24.8 % probability of toxic effects towards aquatic organisms, with Cu, Zn, Cd, and Ni being the main contributors. Comparative analysis suggested that the DGT-SSD coupled PRA could provide a more objective and scientific evidence for lake management with regard to metal contamination.
基于生物有效性的概率风险评估是一种针对水生生物的痕量金属风险特征描述的有效方法。然而，由于研究有限，该方法尚未在湖泊管理中得到常规应用。本研究选择中国安徽省的巢湖作为案例研究，采用化学提取和薄膜扩散梯度技术（DGT）研究了表层沉积物中痕量金属的总量和生物有效性浓度。采用蒙特卡罗模拟法进行概率风险评估（PRA）。此外，还利用急性毒性数据构建了物种敏感性分布（SSD），以模拟水生生物对金属的敏感性。本研究采用了三种评价方法，即基于总含量的毒性单位、基于化学分馏的修正潜在生态风险指数（RI）和 DGT-SSD 耦合 PRA，并进行了比较。结果表明，痕量金属，尤其是 Cd，受到人类活动的显著影响。化学分馏分析表明，大部分 Cd 对水生生物具有较高的生物有效性，而 Cr 在正常条件下较为稳定。基于总含量的毒性单位表明，沉积物中的金属处于 91.6%低毒性和 8.4%中等毒性水平，而基于化学分馏的修正 RI 发现毒性水平分别为 84.1%低毒性和 15.9%中等毒性。此外，由 DGT-SSD 耦合 PRA 计算出的综合毒性表明，沉积物中的痕量金属对水生生物具有 24.8%的毒性效应概率，Cu、Zn、Cd 和 Ni 是主要贡献者。对比分析表明，DGT-SSD 耦合 PRA 可为金属污染的湖泊管理提供更客观、科学的依据。
