Distributions and Sources of Heavy Metals and Polycyclic Aromatic Hydrocarbons in Surface Sediments of Luan River Estuary, North China.

In recent decades, the Luan River Basin has been changed significantly by human activities. The runoff and sediment load decreased sharply. The influences of Luan River on the coastal marine environment also changed. Therefore, this study focused on the relationships between estuary environment status and Luan River discharge in recent years. In this study, 33 surface sediment samples were collected from Luan River Estuary. Grain size and concentrations of total organic carbon (TOC), heavy metals (Cu, Pb, Zn, Cd, Cr, Ni, As and Hg) and PAHs (16 US EPA priority PAHs) were analyzed. The mean concentrations of heavy metals were 18.76μg/g for Cu, 30.98μg/g for Pb, 44.63μg/g for Zn, 41.14μg/g for Cr, 15.60μg/g for Ni, 0.09μg/g for Cd, 7.21μg/g for As and 0.02μg/g for Hg. High concentrations were observed in the samples with fine particles that were collected from the estuary and south part. The concentrations of heavy metals were highly correlated to each other. Human discharges and natural sources contributed 64.2% and 35.8% of heavy metals in this region, respectively. Distinctly different distribution pattern were presented by PAHs and heavy metals. PAHs species were dominated by 4 rings compounds. There was no correlation between PAHs concentration and TOC, grain size or heavy metal contents. Luan River played a much smaller role on the inputs of PAHs than heavy metals in this region. 40.3%, 46.7% and 12.0% of PAHs in this region originated from pollution of oil and oil-products, combustion of fossil fuel and biomass and exhaust of vehicles and ships.