Potentially toxic elements of lake and wetland in Northeastern Qinghai-Tibet Plateau: Distribution, potential sources and risk assessment

• The study area showed no contamination and low ecological risk by PTEs except Cd. • Human health risk assessment showed that children were more sensitive to PTEs than adults. • PTEs were at no non-carcinogenic risk to adults or children in the study. • Three sources of elements were identified using the Self-organizing maps (SOM). The accumulation of toxic elements from sediments poses imminent threats to both the environment and humans. The variation of elements in different sedimentary systems within the same watershed is of significant importance for distinguishing the human activities and adopting relevant management strategies. Based on the surface sediment samples from the Lake Keluke and its wetland, the content and grain size of elements were analyzed. The human health risk indicated in the area the potentially toxic elements (PTEs: Cr, Cu, Zn, Cd and Pb) were at no non-carcinogenic risk to adults or children. Except for Cd, the pollution levels of other PTEs were clean, and potential ecological risk with a low level. However, the pollution of Cd implicated a moderate to heavy pollution intensity and a high ecological risk. According to principal component analysis (PCA), and self-organizing maps (SOM), the main sources of PTEs were of the weathering and leaching of bedrocks; transportation and human agriculture activities. The watershed should reduce pollution caused by human activities and implement efficient agricultural practices.