Contamination of heavy metals and isotopic tracing of Pb in intertidal surface sediments of Jinjiang River Estuary, SE China

Contamination of 14 heavy metals and isotopic tracing of Pb were studied in the intertidal surface sediments of Jinjiang River Estuary, southeast China. Concentrations of the heavy metals in the sediments decrease as Fe > Ti > Mn > Zn > Cu > Cr > Pb > V > Ni > Sn > Co > Sb > Cd > Hg. Except Fe, Ti and V, the other elements show higher concentrations than their background values at most sampling sites. The assessment results of geo-accumulation index and potential ecological risk index indicate that the intertidal surface sediments are polluted by some heavy metals (Cd, Hg, Cu, Mn, Zn, Sb, Sn, Pb, Cr, Ni and Co) and show very high ecological risk with the main contributors of Cd and Hg. Results of multivariate statistic analysis suggest that Fe, V, Ti and Cr are mainly influenced by natural sources; Cu, Ni, Sn and Mn are mainly influenced by mining industries and the combustion of fossil fuel; Pb and Hg are mainly influenced by coal combustion and Pb-Zn ore; Zn, Cd, Co and Sb are mainly influenced by agricultural activities. The results of Pb isotope tracing show that total Pb in the sediments is mainly from parent material (44.0%–50.0%), Pb-Zn ore (35.8%–41.7%) and vehicle exhaust (7.8%–18.2%). - Highlights: • Contents of most examined heavy metals are higher than the background values. • The surface sediments have been polluted by some heavy metals including Pb. • Cd and Hg are the main contributors to the high ecological risk of sediments. • Coal combustion is not the main Pb anthropogenic source in the study area. • Pb is mainly from parent material (47%), Pb-Zn ore (40%) and vehicle exhaust (13%).