东海沉积物中重金属环境背景值的估算及异常站位的判别

EVALUATION OF THE BACKGROUND LEVELS AND JUDGEMENT OF THE EXTRAORDINARY SAMPLING STATIONS OF HEAVY METALS IN THE SEDIMENTS OF THE EAST CHINA SEA

在海洋沉积物污染监测中,首要的问题是确定给定海区的正常环境背景值范围,这是估价污染状况的基础。这个问题受到许多研究者的重视,但迄今尚未得到彻底解决,因而给评价工作造成困难。本工作在1979年东海污染调查的基础上,通过消除各种影响环境背景值的因素,确定东海沉积物中各重金属含量的环境背景值,进而判别异常站位的存在。一、东海沉积物中重金属环境背景值的估算(一) 影响沉积物中重金属背景值的因素影响沉积物中重金属背景值的因素较多,情况较为复杂,归结起来有四个方面: (1) 海区差别不同海区沉积物中重金属的天然积累水平往往由于水文条件、地质状况和沉积环境等条件的不同而显著差别。

The factors affecting the background levels of heavy metal contents in the sediments are considered:(1)variation of natural conditions with survey area difference;(2)effects of environmental factors;(3)effects of pollution;(4)effects of sedimental basis.A complex correction method to eliminate the effects of the factors on the background level of heavy metals of the East China Sea is provided.This paper evaluates the back ground levels of Hg,Cu,Pb,Zn and Cr in the sediments.Calculated background value plus three standard deviations were decided to be the lower limit of the permitted criterion of the extraordinary sampling stations.The method for the judgement of extraordinary content samples of heavy metals is presented.The results of the judgemet show that the content of Hg,Cu,Pb,Zn and Cr in most of the sediment samples are in the range of normal level,except for a few samples.