Potentially toxic elements in lake sediments in China: Spatial distribution, ecological risks, and influencing factors

Potentially toxic elements (PTEs) pollution in lake sediments is a serious threat to the ecological safety of lake water and human health, owing to anthropogenic activities. Studies on the distribution of pollution, the differences in lake types, and the influencing factors in China as a whole are lacking. This study collected data on PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in Chinese lake sediments published from 2005 to 2021, and aimed to evaluate pollution levels and spatial distribution characteristics of PTEs in lake sediments, differences in pollution in different types of lakes, and influencing factors. The results showed that (1) All metals in the lake sediments accumulated to different degrees, when compared to the background values. (2) The lake type pollution levels were ranked: urban lakes > reservoirs > plateau lakes > natural lakes. (3) The geoaccumulation and potential ecological risk indexes both indicated that Cd and Hg are the main pollutants, and that the overall ecological risk level of lake sediments in China is high. (4) The degree of economic and population growth is highly correlated with the concentrations of eight PTEs; the amount of fertilizer and pesticide used in agricultural activities are the main factors affecting As and Hg; industrial activities and traffic pollution emissions are the predominant factors affecting Cu and Ni. (5) In the interaction detection analysis, the Cr content was mainly influenced by natural factors; Cd, Pb, and Zn contents were affected more by human activities. This study provides a reference for understanding the current status and influencing factors of PTE pollution in Chinese lakes.