Heavy Metals in the Water and Sediments of Guanting Reservoir

The distribution and behavior of heavy metals (Cn,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.