利用小型底栖动物对沉积物重金属污染的评估

Study on the Use of Meiofauna Parameters to Assess Heavy Metal Pollution in Sediments

采用Hakanson的生态风险指数法和自由生活海洋线虫与底栖桡足类数量之比(N/C比值)的变动对长江口及其邻近海域沉积环境重金属污染状况进行评估。结果表明,研究海域沉积物受到重金属元素Cr,Cu,Zn和As不同程度的污染,近岸站位受测各污染物均呈现中度污染,离岸站位为轻度污染,其中Zn累积最严重。单个污染物潜在生态危害参数表明,受测污染物对海洋生态系统的潜在生态危害非常轻微,其中As和Cu是最主要的生态风险贡献因子。小型底栖动物群落丰度及分布验证了此结果,对As和Cu累积具有明显的生态响应。N/C比值法对研究海域沉积物重金属的污染评估结果与Hakanson的生态风险指数评估结果基本一致,特别是对Cu和As元素的污染评估。结合生物群落分析,利用小型底栖动物两大类群数量之比(N/C)是一个简易可行的沉积环境监测方法。

This paper describes the numerical distribution of meiofauna community collected at 14 stations in the Changjiang River Estuary and its adjacent waters. The contents of typical pollutants （Cr, Cu, Zn and As） in the sediments were analyzed and the Hakanson＇ s Ecological Risk Index Method was applied to assess the potential ecological risk of the study area. At the same time, the ratio of marine nematodes to benthic copepods （N/C ratio） was briefly introduced and used to evaluate the sedimental environment quality. The evaluation resuits show that the sediments of the study area are in different qualities. The quality of sediments is poor near the coast and Zn is the most serious pollutant. However, the Hakanson＇s Ecological Risk Index shows that all pollutants pose low risks in the study area. As and Cu are the main risk contributors. Ecological responses of meiofauna community parameters are obviously discovered in the validation. The evaluation based on N/C ratio exhibits the same results with Hakanson＇ s Ecological Risk Index method. There fore, the application of the N/C ratio is a useful monitoring method for pollution evaluation of metals in sedimental environment.