Pollution, cumulative ecological risk and source apportionment of heavy metals in water bodies and river sediments near the Luanchuan molybdenum mining area in the Xiaoqinling Mountains, China.

The water and sediment samples were collected from the Yu River and Taowanbei River during periods of summer and winter. The NCPI , EWQI , I geo and PERI were used to evaluate the pollution degree and cumulative ecological risk of HMs in the water and sediments. The PMF model was used to analyze the sources of HMs in river sediments. The pollution degree of Cd, Hg and Zn in the water reached the severe pollution level, in the rank of Hg > Zn > Cd. Cd and Zn in sediments are heavily polluted, Cu is lightly polluted, Pb and As are within the warning range, and the pollution rank is Cd > Zn > Cu > Pb > As. The cumulative ecological risk of HMs in sediments reached extremely strong level, mainly Cd and Hg. The main sources of HMs in sediments are mining sources, mixed agricultural and transport sources, and natural sources, which contributed 42.1 %, 34.1 % and 23.8 %, respectively. [Display omitted] • The main polluting elements in water bodies and sediments are Cd, Zn, Cu, Hg. • HMs in sediments have serious cumulative ecological risks, mainly Cd and Hg. • Hydrodynamic conditions are the main factor influencing the release and migration of HMs. • Seasonal variations affect the adsorption and desorption processes of HMs in sediments. • Mining is the main source of HMs in sediments, contributing 42.1 %. [ABSTRACT FROM AUTHOR]