典型汞污染河流生物膜和沉积物中汞的分布特征

Distribution Characteristics of Mercury in Biofilm and Sediment of A Typical Mercury Contaminated River

为弄清汞污染历史河流水体、生物膜和沉积物中汞污染现状和潜在风险,本研究选择贵州省清镇市东门桥河为研究对象,采集河流水体、生物膜和沉积物样品,并测定其汞的形态含量。结果表明,东门桥河水体总汞(THg)、溶解态汞(DHg)和颗粒态汞(PHg)的平均含量分别为66.46±51.87 ng/L、10.67±5.15 ng/L和55.79±50.26 ng/L,PHg含量高达72%。生物膜中THg和MeHg的平均含量分别为9.38±12.39 mg/kg、19.58±22.21μg/kg;沉积物中THg和MeHg的平均含量分别为30.89±24.64 mg/kg、21.50±7.20μg/kg。水体和生物膜中汞的季节分布特征为夏季>秋季>春季。受清淤情况和市政污水排放的影响,随着采样点逐渐远离总排污口,水体汞含量呈现逐渐升高的趋势,而沉积物和生物膜的汞含量呈现出逐渐下降的趋势。

In order to clarify the current status and potential risks of mercury in river water,biofilm and sediment of mercury polluted rivers,this study selected the Dongmenqiao River as the research object,collected river water,biofilm and sediment samples,and determined contents of mercury in these samples. The results showed that the average contents of total mercury( THg),dissolved mercury( DHg) and particulate mercury( PHg) in the Dongmenqiao River were 66.46±51.87 ng/L,10.67±5.15 ng/L and 55.79±50.26 ng/L,respectively,the PHg content is as high as 72%. The average contents of THg and MeHg in biofilm samples were 9.38±12.39 mg/kg and 19.58±22.21 μg/kg,respectively. The average contents of THg and MeHg in sediment samples were 30.89±24.64 mg/kg and 21.50±7.20 μg/kg,respectively. The seasonal distributions of mercury in water and biofilm samples were similar with a trend of summer > autumn > spring. The mercury contents increased gradually in water samples and decreased gradually in sediment and biofilm samples as distances of sampling points to the total sewage outlet increased,reflecting the effect of dredging and municipal sewage discharging.