长江口近岸表层海水污染因子的分类判别与环境质量综合评价

CLASSIFYING OF SURFACE SEAWATER POLLUTION FACTORS AND ASSESSING OF ENVIRONMENTAL COMPREHENSIVE QUALITY IN CHANGJIANG ESTUARY INSHORE

根据2003—2008年进行的对长江口近岸海域表层水质12个航次的监测统计结果,采用参评因子动态排序法,对近年来长江口近岸海域表层海水中的主要污染因子进行了分类判别,综合评价了长江口近岸海域表层海水环境质量状况。结果表明,近5年来长江口近岸海域表层海水环境中CODMn为常态因子,DIN、PO4-P、Hg和Pb为关键因子,As和Cd为预警因子;近5年来长江口近岸海域表层海水环境质量总体上处于三类海水水质水平,且海水环境质量有恶化趋势,但幅度不大。此外,参评因子动态排序法的各参评因子的权重值的确定完全建立在监测数据的客观基础上,综合评价结果不受人为主观因素的影响,反映海水环境综合质量的时空变化特征比较客观,具有普适性,值得在海洋环境评价领域推广。

Basing on the monitoring-statistical results of surface water quality of Changjiang Estuary inshore in Mays and Augusts from 2003 to 2008,the classifying of main pollution factors was performed,a comprehensive assessment was given on the seawater environmental quality by applying the Assessing Factor Dynamic Sorting method.The assessing results showed that CODMn was Normal Factor,DIN,PO4-P,Hg,and Pb were Pivotal Factor,As and Cd were Warning Factor in surface seawater of Changjiang Estuary in recent five years.As a whole,the comprehensive environmental quality of Changjiang estuary was at Ⅲ grade sea water quality level,but it gets worsen with time in recent years.Moreover,the weights of assessing factors were completely based on the monitoring data in the Assessing Factor Dynamic Sorting method,the comprehensive assessing results are not affected by artificial subjective factors,it is more objective to compare seawater comprehensive environmental quality among different periods and spaces.This method is worth being generalized in the ocean environment assessment field with being universal.