Pollution characteristics and potential ecological risk assessment of metals in the sediments of Xiaoqing River, Jinan

The spatial–temporal changing characteristics and potential ecological risk combined with local policies and industrial status were analyzed. The metal contamination was studied by sediment quality guidelines (SQGs), potential ecological risk index (PERI), and geoaccumulation index (I_geo) of metals (Hg, Cr, Cd, As, Pb, and Cu) in the sediments of Xiaoqing River in Jinan from 1996 to 2014. Results showed that the concentrations of metals were in fluctuation and had a decreasing trend in the past 19 years, which was influenced by industry and policy. The concentrations of metals from upstream to downstream presented a change from low to high and then a gradual decrease which were mainly related to anthropogenic activities. The assessment suggested that Hg presented the highest levels of I_geo and was the largest contributor to RI, while Cd was the second contributor. This finding indicated that Hg and Cd had a strong effect on potential ecological risk. Damatou had the largest pollution level and potential ecological risk, whereas Mulizhuang was the least polluted area. SQGs indicated that Cd was below the TEC while it was the second contributor to potential ecological risk. Indeed, the pollution control of Xiaoqing River had a certain effect, but it needs long-term effective management measures and a strengthened source control. The suggestions of targeted management have been proposed in the paper.