Mercury concentrations in environmental media at a hazardous solid waste landfill site and mercury emissions from the site

Abstract

Mercury (Hg) concentrations in air, effluent water, landfill gas, leachate, groundwater, and soil at a hazardous solid waste landfill site in Korea were measured along with air–soil surface Hg exchange fluxes at the site. The concentrations and fluxes were considerably higher than have been found elsewhere in Korea. Gaseous Hg concentrations in the air peaked during the day, coinciding with Hg being released from the landfill surface. This suggests that air–soil exchange increased the Hg concentrations in the atmosphere. The air–soil exchange flux increased abruptly when solar radiation reached the soil surface. The Hg flux peaked about 3 h before the solar radiation peaked, possibly because reducible Hg was abundant at the soil surface. The Hg emission flux activation energy (E a) was low, indicating that the Hg species present and Hg–soil binding were probably not as important (because of the high Hg content of the soil) as in previous studies. The methylmercury to total Hg ratios in the discharged effluent, groundwater, and leachate was clearly higher than typically found in coastal water and freshwater, suggesting bacteria caused active methylation to occur under the reducing conditions in the anaerobic landfill. The results suggested that considerable amounts of Hg are probably transported from the landfill to nearby environmental media and that this will continue if waste with a high Hg content continues to be added to the landfill without being pretreated.