Assessment and source analysis of heavy metal contamination in water and surface sediment in Dongping Lake, China.

Dongping Lake is the only natural lake in the lower Yellow River and an important hub of South-North Water Diversion Project, its water quality is of vital importance to the environmental protection and the security of water supply. To assess the heavy metal (HM) contamination in Dongping Lake, samples in water and surface sediment were taken from 59 sampling sites over the entire lake. The statistical characteristics, pollution conditions, and source identifications were analyzed using coupling methods of entropy water quality index (EWQI), modified pollution index (mC), enrichment coefficient (EF), geo-accumulation index (I), potential ecological risk index (PERI), and positive matrix factorization (PMF).