珠江三角洲河网区水体及鱼体内重金属含量分析与评价

Evaluation on Heavy Metal Contents in Water and Fishes Collected from the Waterway in the Pearl River Delta,South China

采用原子吸收及原子荧光法,对珠江三角洲河网区水体及鱼体中重金属Cr、Cu、Pb、Fe、Zn、Mn、Ni、Cd、As和Hg含量进行了检测,并以国家地表水环境质量标准(Ⅲ类)及水产品中有毒有害物质限量进行了评价。结果表明,水体中Cr、Pb和Hg为主要污染元素,超标率分别为22.2%、11.1%和5.6%,水体中不同季节Pb和Cr含量变化基本特征为丰水期>平水期>枯水期,河网不同江段变化特征不同,这与重金属在水体中的存在形态及受水动力条件影响有关;鱼体中残留的重金属元素有Cr、Pb和As,超标率分别为36.7%、27.1%和6.3%,超标鱼类主要分布于肇庆-富湾及大塘-三水江段。不同鱼类重金属元素残留特征为底层鱼大于中上层鱼,肉食性鱼大于植食性鱼和杂食性鱼。Pb和Cr为珠江三角洲河网区水体及鱼体中重金属污染的主要元素。

The contents and distributions of heavy metals in water and fishes collected from the waterway in the Pearl River Delta of South China were investigated in May to December 2009.The contents of chromium（Cr）,copper（Cu）,lead（Pb）,iron（Fe）,zinc（Zn）,manganese（Mn）,nicke（lNi）,cadmium（Cd）,arsenic（As）and mercury（Hg）in all samples were measured by flame atomic absorption spectrometry and atomic fluorescence spectrometry.Introduced the ＂Chinese grade Ⅲ of national environmental quality standards for surface water＂and the ＂Limiting standard of noxious and nocuous matters for aquatic products＂to evaluate the pollution levels and edible security.The results showed that the main overproof elelments in waters were Cr,Pb and Hg with standard-exceeding rate of 22.2%,11.1% and 5.6%,respective-ly.The season variation of Pb and Cr content in waters was characterized with the following sequence：high-water seasonmiddle-water sea-sonlow-water season,which was related to the existing form,transferring and transforms of heavy metals,and also affected by water dynam-ics.The main residues of heavy metal in fish samples were Cr,Pb and As with standard-exceeding rate of 36.7%,27.1% and 6.3%,respec-tively.It showed that the standard-exceeding samples collected from Zhaoqing-Fuwan and Datang-Shanshui reach.The results also showed that residues of heavy metals in fish was different.It was higher for concentrations of heavy metal in demersal fish species than that in pelagic fish species,and residues of heavy metals in piscivorous were higher than that in herbivorous.The results indicated that Cr and Pb were the main heavy metal pollutants in fish and water from Pearl River Delta waterway.