Ecological risk assessment and sources identification of potentially toxic elements in the surface sediments of Qinghai Lake

Abstract

The Qinghai Lake, a quintessential representative of the world's plateau inland lakes, has garnered much scrutiny from scholars for its current status of potentially toxic elements (PTEs) pollution. Hence, this study investigated the concentrations and distribution of seven PTEs i.e., Co, Cr, Cu, Ni, Pb, Zn and V. Furthermore, the potential ecological risk index (RI), self-organizing maps (SOM), correlation analysis and positive matrix factorization (PMF) were used to explore the level of risk and sources of pollution in the study area. The study revealed that: (1) the contents of PTEs in Qinghai Lake sediments were lower than other regions, yet 25.0% of Pb and 19.4% of Zn remained above background values, and the spatial distribution was more heterogeneous; (2) the high ecological risk in the sediment was spread mainly in the downstream of the estuary and the vicinity of tourist sites, where the ecological risk index of Pb was the maximum; (3) correlation and model analysis showed that the seven PTEs were homologous, and besides natural sources, transportation, mixed agricultural cultivation and coal-fired sources were presumed to be the main anthropogenic sources of disturbance. In the midst of rapid economic development, environmental pollution of the Qinghai Lake should be strictly controlled to avoid increased risks.