Characteristics of nutrients pollution and ecological risk assessment of heavy metal in sediments of Fenhe River, Taiyuan Section, China

This study was aim to reveal the characteristics of nutrients and heavy metals associated with ecological risks in the sediments of Fenhe River, Taiyuan Section. The concentrations of nutrients (TN, TP, TOM) and heavy metals (As, Cu, Zn, Pb, Cr, Ni, Hg, Cd) were investigated. Spatial distribution, correlation analysis and source identification were facilitated to indicate nutrients and heavy metal pollution's characteristics. Evaluations of heavy metals' contamination degree were achieved by comprehensive ecological risk indexes including I-geo, I-in, C-f, PLI and RI. The results showed that nutrients were accumulated in the middle part and were mainly from embryophyte, zooplankton and phytoplankton or algae based on C/N values. Large spatial variabilities existed in heavy metals distribution patterns and source identification of heavy metals were natural sources and anthropogenic activities based on PCA model. Results of different ecological risk indexes showed that pollution associated with Hg was rated as moderate ecological risk which was the significant contamination, higher ecological risks mainly existed in the middle part.