珠江口沉积物重金属背景值及其污染研究

Background values and contamination of heavy metals in sediments from the Pearl River Estuary

采用珠江口348个表层和2个柱状沉积物样品的重金属数据,结合数理统计方法,估算了珠江口沉积物重金属背景值.同时,利用柱状样品结果对背景值进行检验,并与其他研究成果对比.研究区Cu、Pb、Zn、Cr和Ni的背景值分别为16.1、21.9、94.3、69.3和30.3μg·g-1,且本文获得的重金属背景值更具有代表性.最后,采用获得的重金属背景值对珠江口区域污染状况进行研究,发现珠江口大部分区域的表层沉积物中单个重金属元素及总体污染程度属于中、低水平,重污染区主要分布在珠江八大口门附近区域,特别是东四门的西滩.ZY1柱状样品结果显示,1997—2003年间各重金属含量及污染程度均快速上升,2003—2005年间增速虽减缓,但2005年以后又呈现增大现象,重金属污染历史记录较好地反映了珠江三角洲流域社会经济和人类活动对重金属输入的影响.

By using statistical methods, the background values of heavy metals in sediments of the Pearl River Estuary （PRE） were estimated based on the heavy metals date of 348 surface sediments and 2 sediments cores from the PRE. The background values of Cu, Pb, Zn, Cr and Ni are derived as 16.1, 21.9, 94.3, 69.3 and 30.3 μg g-1, respectively, which is believed more representative by sediment core tests and comparison with other studies. In addition, the contamination levels of heavy metals in sediments of PRE were assessed. The results showed that both of the single heavy metal pollution and overall pollution were in moderate-and low-level in surface sediments from most regions of the PRE, and the heavily polluted area were mainly distributed near the eight outlets of the Pearl River, especially in the West Beach of the east four outlets. The results of core ZY1 indicated that the heavy metal content increased quickly from 1997 to 2003, and then increased quickly from 2005 again after a slight growth from 2003 to 2005. The history of heavy metal pollution can better reflect the impact of the socio-economic development and human activities in the Pearl River Delta.