珠江口淇澳岛海岸带沉积柱重金属分布特征及污染评价

Contamination assessment and distribution characteristics of heavy metals in sediment core in costal zone of QiAo Island in Pearl River Estuary

为研究珠江口近30 a来的重金属污染状况,自伶仃洋淇澳岛海岸带采集了1个长108 cm的沉积物柱(ZH1)。分析了这些沉积物样品中12种微量金属的含量及粒度参数。结果表明,沉积柱中的重金属呈现四种垂向分布模式。有机质含量是大部分重金属垂向分布的主要控制因素。采用地累积指数法对沉积柱中各重金属元素污染的垂向变化进行了评价,结果表明,Cr、V、Be、Se、Sn和Tl基本上未受污染,而Cu、Ni、Pb、Zn、Cd和Co均受到了不同程度的污染,推测这些元素的污染与富集可能主要与上世纪80年代初起至今人类活动(工业、农业及生活)对珠江口产生的影响逐渐增加有关。另外,也与研究区位于珠江口西侧的水动力条件有关。

Due to understand the heavy metals contamination in the Pearl River Estuary in last three decades,a 108 cm long sediment core（ZH1） was taken from the coastal zone along the Qiao Island in the Lingding Bay in the Pearl River Estuary.The subsamples sliced from the core were analyzed for concentrations of twelve trace metals and grain size.Four vertical distribution patterns of the heavy metals were identified respectively.The results showed that the grain size is not a main controlling factor for the vertical distributions of the heavy metals except some elements.TOC might be a main controlling factor.The contamination assessment on the heavy metals in the sediment core adopting Index of Geo-accumulation（Igeo） showed that Cr,V,Be,Se,Sn and Tl were unpolluted,while Cu,Ni,Pb,Zn,Cd and Co were polluted in different degrees throughout the core.It is presumed that the contaminations or enrichments of these metals might be related to gradually intensive anthropogenic activities（industrial,agricultural and domestic） in the estuary since early 1980s.In addition,hydrodynamic condition might be another important influencing factor.