江苏新洋港潮滩湿地重金属元素Pb、Cu、Zn、Cr分布特征及污染评价

Distribution and pollution assessment of the heavy metals Pb,Cu,Zn and Cr in the Xinyanggang tidal flat

通过对保护区新洋港核心区潮滩表层、柱状沉积物以及不同地貌和植被条件下重金属Cu、Zn、Cr、Pb含量的分析,利用地累积指数法、元素富集指数法、潜在生态危害指数法,对潮滩重金属的污染状况和金属元素富集规律进行了初步研究,并利用不同的指标进行相互验证,分析了生态带植被和沉积物间的重金属地球化学累积.结果表明,1)新洋港的重金属元素Zn、Pb、Cu含量变化走势基本相同,元素归一化后,所有重金属元素的归一化值变化波动范围均比重金属含量值明显收窄,波峰和波谷有后延的趋势,波动趋势基本没变.2)从水平断面的重金属含量分布特点来看,都表现出了从高潮滩向低潮滩递减的趋势,但是递减的速度不同.Cu、Ni、Zn从高潮滩到低潮滩含量递减趋势较明显,Cr、Pb则没有明显的递减趋势.3)新洋港潮间带沉积物中元素Pb、Cr与长江口、黄河口以及中国浅海沉积物和江苏土壤相比呈现不同程度的富集.Pb超出最多,其EF值达到3.774.4)新洋港RI值为23.552,虽然存在一定的重金属富集和污染,但其尚未产生生态危害,整体新洋港核心区重金属环境质量优良.

The heavy metals Pb, Cu, Zn and Cr were analyzed in surface samples and core samples collected in the center of the Xinyanggang tidal area, and the overall heavy metal pollution and elemental distribution were studied. The geoaccumulation index, element accumulation index and potential ecological risk index are applied in this study. The following conclusions were obtained： 1 ） The distribution of Pb, Cu, Zn and Cr follow the same trend in the Xinyanggang area. After standardizing the data, the distribution trend remained the same, but being less in changing scopes. 2）The contents of Pb, Cu, Zn and Cr in the area decline from the upper tidal flat to the lower tidal flat, but at different rates. The content of Cu, Ni and Zn declines rapidly, while Cr and Pb change slowly. 3）Compared with the average levels of Pb and Cr in sediments along the Chinese coast, local Pb and Cr appear to be highly accumulated, which reveals the heavy pollution in the Xinyanggang area. 4）The risk index （RI） was 23. 552 locally, which indicates a weak ecological risk in the area and the environmental quality remains good.