江苏王港海岸带沉积物重金属污染研究

Heavy Metal Contamination in Coastal Sediments of Wanggang, Jiangsu Province

对江苏王港海岸从岸向海的4种不同土地类型(农田、鱼塘、米草滩和河口粉砂细砂滩)的沉积物进行柱状取样,对样品进行了粒度、主要重金属元素和有机碳等分析。结果表明,沉积物粒径以粉砂为主,并且从陆向海粒径变粗,砂的含量逐渐增多;除了鱼塘之外,都出现表层富集重金属元素,其中农田因为人类耕种以及成土作用,重金属元素向下先减少再增多;鱼塘因围垦后环境较为稳定,无明显变化;米草滩因为沉积环境和植被的影响,出现表层富集,向下迅速减少;河口粉沙滩因水动力较强,各种元素向下波动减少。通过与沉积物粒度和有机碳的相关性比较,农田中重金属含量与其相关较低,而米草滩重金属含量主要受沉积物颗粒和有机碳控制。根据与江苏沿海平原土壤元素含量平均值相比,王港海岸带的4个位置出现较为严重的Pb污染;在农田、米草滩以及河口光滩出现一定的Cu污染,这种空间污染状况是当地人类活动与特殊的自然环境共同作用的结果。

Four sediment cores （56-74 cm） were collected from four types of land use and cover： farmland, pound, Spartina alterniflora tide flat and mud-silt tide flat in the coast of Wanggang area, Jiangsu province. The sediment grain size, the heavy metal elements and the TOC were analyzed. The sediment of Wanggang coast was composed mostly of silt and the grain size increased seaward. The heavy metals enriched in surface in farmland, Spartina alterniflora tide flat and mud-silt tide flat. Vertical distributions of heavy metals revealed the influence of variable sediment environment and anthropogenic inputs. Compared to the soil of the Jiangsu coastal plain, the contamination of Pb was higher in all of Wanggang coast because of atmospheric deposition. Cu also accumulated in the surface of farmland, Spartina alterniflora tide flat and mud-silt tide flat. The heavy metal contamination was controlled by the clay and the TOC because of their high correlations in the Spartina alterniflora tide flat, while, it was controlled by sediment environment and anthropogenic inputs in Wanggang coast.