官厅水库水和沉积物中的重金属

Heavy Metals in the Water and Sediments of Guanting Reservoir

研究了官厅水库水和沉积物中重金属铜、铅、锌、镉的分布和行为特性。结果表明,它们在水体中以可溶态存在的只占4.2％,大部分赋存于悬浮物中。对这些重金属在沉积物中的赋存状态作了研究,结果表明,可交换态的比例仅为0.6％。重金属在水体的分布可反映污染源和沿途沉积的影响.从不同沉积期底质中的重金属含量可以推断其污染历程。长期水质变化趋势表明,水中重金属含量在1985年前呈上升趋势,以后呈下降趋势,其原因是由于水体含沙量的变化。

The distribution and behavior of heavy metals (Cu,Pb,Zn,Cd) in the water and sediments of Guanting Reservoir which supplies water for Beijing city were studied. The results for the water column show that the mean percentage of metals in the solute phase is 4.2 %, and that most are associated with suspended sediment. The content of metals in the bed materials is from 5000 to 10000 times higher than dissolved in the water. The exchangeable metals in the bed materials represents only 0.6% of the total. This indicates that metals in the sediments are not greatly affected by surface adsorption. The spatial distribution of metals within the reservoir reflects pollution from various sources. The spatial variation in metal concentrations provides information on temporal changes in the water quality and pollution. The trends of metals in the water show that pollution increased from 1973 to 1985, but it decreased since 1985.