Study On The Distribution Of Mercury And Other Trace Elements In Xiaolangdi Reservoir

A few researches reported elevated MeHg concentrations in fish found in lakes located far from point sources in northern Europe and North America. The MeHg levels which higher than the criterion of mercury content in edible aquatic product recommended by the World Health Organization. Xiaolangdi reservoir was the source of drinking water of Zhengzhou City, with very important social and economic functions. April in 2009,May and November in 2010,the concentration and distribution of mercury, methylmercury, selenium, manganese, cadmium, iron, arsenic, chromium, copper, zinc lead and fluride in water columns in Xiaolangdi reservoir were researched.Through the detailed studies reported in this thesis,some main conclusions were obtained as follows:1.Total mercury(THg) in Mingzhudao of Xiaolangdi Reservoir ranged from 5.7 to 21.6ng/L, with an average of 11.6ng/L, total methylmercury(TMeHg) ranged from 0.02 to 0.1ng/L, with an average of 0.045ng/L; total mercury(THg) in Luoyu ranged from 5.2 to 44.4ng/L, with an average of 13ng/L,total methylmercury(TMeHg) ranged from 0.02 to 0.07ng/L, with an average of 0.039ng/L. total mercury(THg) in Dabaqian ranged from 6.7 to 43.3ng/L,with an average of 19.5ng/L, total methylmercury(TMeHg) ranged from 0.01 to 0.07ng/L,with an average of 0.037ng/L.The percent of HgT as TMeHg was approx. 0.35% in Mingzhudao and approx.0.47% in Luoyu and approx.0.21% in Dabaqian.2. Mercury concentration in Xiaolangdi water system shows a increasing trend from upstream toward the dam. The highest mercury concentration was found in Dabaqian. Total mercury concentration in Luoyu was higher than that in Mingzhudao, The highest total mercury concentration was observed at 16m in Luoyu. Mercury content in main channel is higher than in the Gushanxia tributary. Total mercury content in bottom water is slightly higher than that in surface water.3,The methylmercury average concentration changed a little from upstream to downstream Xiaolangdi reservoir. Methylmercury concentrations have a little change with depth. Concentrations of methylmercury in the surface water were higher than those of intermediate water; it was lower than the methylmercury mercury content in bottom water.4,Total mercury in Xiaolangdi reservoir was associated with methylmercury just in low flow period.5,Other trace elements content in main channel is higher than those of the Gushanxia tributary. The concentrations of arsenic, selenium, zinc, copper, manganese, cadmium, chromium and lead in Xiaolangdi reservior were lower than the national water quality standard for drinking water sources.