Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
Engineering Research Center of Ministry of Education on Groundwater Pollution Control and Remediation, College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
Sci Total Environ. 2019 Dec 1;694:133819. doi: 10.1016/j.scitotenv.2019.133819. Epub 2019 Aug 6.
Heavy metals (HMs) in lake sediments have aroused long-term attention due to their persistent threat to the lake ecosystems. Study into the pollution characteristics and potential sources of HMs in lakes, especially those heavily influenced by human activities, can give some insights to prevent and control the environmental risks of HMs. Lake Tai is the China's third largest freshwater lake but has been a drastic example of water pollution in recent decades. Here, we systematically investigated the characterization of pollution, risk and sources of HMs in the sediments of Lake Tai and its surrounding soils using several methods and tools. Specifically, a total of 46 sediments and 578 soils were collected from the study area, and geochemical approaches (geo-accumulation index and enrichment factor) and pollution indexes were jointly used to reveal the contamination characteristics of HMs. Meanwhile, the potential ecological risk index and probabilistic model of health risk assessment were employed to understand the environmental risk of HMs. Further, absolute principle component score-multiple linear regression and positive matrix factorization models were comparatively applied to apportion the sources of HMs. Results showed that various metals including Cd, Cr, As, Hg, Pb, and Cu appeared contamination level in varying degrees both in the sediments and soils. In particular, Cd, As and Hg were identified as the significant contaminants and presented moderate ecological risk. As a whole, the health risk levels of metals were acceptable. Source apportionment suggested that industrial discharge, agricultural activities, atmospheric deposition and natural source were the potential origins of HMs in this area. Among them, anthropogenic activities were the largest dominator of HMs with contribution of >75%. The study will advance our knowledge on HMs in lake and its surrounding soils and provide reference for policy maker to design migration strategies for protecting the lake ecosystems.
重金属（HMs）在湖泊沉积物中引起了长期关注，因为它们对湖泊生态系统构成持续威胁。研究湖泊中 HMs 的污染特征和潜在来源，特别是那些受到人类活动强烈影响的湖泊，有助于预防和控制 HMs 的环境风险。太湖是中国第三大淡水湖，但在最近几十年里，它已成为水污染的一个典型例子。在这里，我们使用多种方法和工具，系统地研究了太湖及其周边土壤沉积物中 HMs 的污染特征、风险和来源。具体来说，共采集了 46 个沉积物和 578 个土壤样本，采用地球化学方法（地积累指数和富集因子）和污染指数联合揭示 HMs 的污染特征。同时，采用潜在生态风险指数和健康风险评估概率模型来了解 HMs 的环境风险。此外，还比较应用了绝对主成分得分-多元线性回归和正定矩阵因子模型来分配 HMs 的来源。结果表明，各种金属包括 Cd、Cr、As、Hg、Pb 和 Cu 在沉积物和土壤中均呈现不同程度的污染水平。特别是 Cd、As 和 Hg 被确定为显著污染物，呈现中度生态风险。总体而言，金属的健康风险水平是可以接受的。来源分配表明，工业排放、农业活动、大气沉降和自然源是该地区 HMs 的潜在来源。其中，人为活动是 HMs 的最大来源，贡献率>75%。该研究将提高我们对湖泊及其周边土壤中 HMs 的认识，并为决策者制定保护湖泊生态系统的迁移策略提供参考。
