滦河口表层沉积物中重金属和多环芳烃的分布、来源及风险评估

为了弄清近年滦河输送与河口环境之间的相关性,对采自滦河口的33个表层沉积物样品的粒度、有机碳、重金属(Cu、Pb、Zn、Cd、Cr、Ni、As、Hg)和多环芳烃(PAHs;16种US EPA优先控制单体)含量进行了检测分析.Cu、Pb、Zn、Cd、Cr、Ni、As、Hg的平均含量分别为18.76,30.98,44.63,41.14,15.60,0.09,7.21和0.02μg/g.重金属含量高值区分布在河口和南部细颗粒中心区域,其分布受沉积环境控制;元素之间相关性较高,河流输送对该区域中重金属含量和分布影响较大;该区域中重金属64.2%源于人为污染释放,35.8%属于自然背景;整体污染程度较低,在河口存在低生态风险.PAHs总浓度为7.5~74.3ng/g,平均为37.4ng/g,PAHs与重金属具有完全不同的分布特征,河流输送影响较小,单体组成以4环单体为主;该区域中沉积物中的PAHs有40.3%源于石油泄漏及船舶航行等,46.7%源于煤炭、天然气及木柴燃烧,12.0%源于交通尾气排放;北部区域锚地船舶航行及石油制品泄漏对北部区域PAHs生态风险贡献较大.

Heavy metals and polycyclic aromatic hydrocarbons in surface sediments of Luan River estuary: distributions,sources and ecological risk assessments

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, 33surface 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(16US EPA priority PAHs) were analyzed. The mean concentrations of Cu, Pb, Zn, Cr, Ni, Cd, As and Hg were 18.76, 30.98, 44.63, 41.14, 15.60, 0.09, 7.21 and 0.02μg/g, respectively. 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 patterns were presented by PAHs and heavy metals. PAHs species were dominated by 4rings 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.