三峡库区香溪河中重金属元素的分布特征

CHARACTERISTICS OF THE DISTRIBUTION OF Cu,Pb,Cd,Cr,Zn IN XIANGXI RIVER

长江三峡水库蓄水后 ,香溪河水环境条件将发生变化 ,也导致该流域内重金属环境化学行为的变化 ,有些金属的危害比现在会更大。为积累蓄水前的基本资料 ,在 1996～ 1997年春、夏、秋、冬四季采集了香溪河原水、沉积物、鱼类和植物样品 ,并对所采集的鱼进行分类 ,分析这些样品中的Ca、Mg、As、Pb、Cd、Cr、Cu、Hg和Zn元素的含量。研究结果显示 ,香溪河局部地区因小金矿开发引起的Hg污染十分严重 ;洪水期 (7月 )原水中的Pb、Cd、Cr、Cu浓度大于枯水期 (1月 ) ;沉积物中Pb、Cd浓度在 7月最低 ,10月浓度达到全年最高点 ;原水中Pb、Cd、Cr、Cu重金属浓度均低于国家Ⅰ类地面水环境质量标准 ;香溪河水中不同种鱼类的金属富集能力各不相同 ,鱼类的重金属富集系数顺序为Cd >Zn >Pb >Ca >Cu >Cr>Mg。统计分析表明鱼体中的Pb和Cd浓度分别与沉积物。

After the reservoir impoundment, flow velocity will decrease, so aquatic environmental conditions will change, the environment chemical behavior of heavy metals in Xiangxi River will change correspondingly, and the impact of some heavy metals will be greater than at the present. In order to investigate these changes, water samples, sediments, fishes and plants were sampled from Xiangxi River in four different seasons from 1996 to 1997. The concentration of Ca, Mg, As, Cd, Cr, Cu, Hg, Zn in these samples were analyzed, and fish species were identified. Results show that pollution of Hg is serious in partial area for the exploitation of small gold mines. The concentration of Pb, Cd, Cr, and Cu in water samples from Xiangxi River during the high-level period is higher than that during the low-level period. The concentration of Pb and Cd in sediments is highest in July, and is lowest in January. According to the Water Quality Standard, the water of Xiangxi River belongs to water class I.The bioaccumulation capability of heavy metals from various fishes is different. Bioconcentration factor(BCF) of different metals are ordered by Cd>Zn>Pb>Ca>Cu>Cr>Mg. It was found that concentrations of Cd, Pb in fish samples are correlated well with that in sediments and water samples, respectively.