Exchange pattern of gaseous elemental mercury in an active urban landfill facility

The environmental behavior of gaseous elemental mercury (Hg) in the ambient air was investigated from the center of a municipal landfill site (area ∼0.6 km2) located in Dae Gu, Korea in the winter of 2004. In order to provide insight on the Hg exchange processes in strong source areas, we continuously analyzed Hg concentration gradients developed across two heights between 1 m and 5 m over soil surfaces at hourly intervals. The results displayed Hg concentrations in the lower and upper levels in the range of 1.46–13.1 ng m−3 (3.33 ± 1.29 ng m−3: N = 139) and 1.20–13.7 ng m−3 (3.27 ± 1.23 ng m−3: N = 139), respectively. The results of our analysis, when divided separately into emission and dry deposition, showed that emission of Hg was fairly dominant in frequency (up to 58%) over dry deposition. By multiplying our Hg gradient data with the K-values predicted indirectly from the results of previous studies, the emission and deposition fluxes of Hg were estimated as 39.0 ± 43.3 ng m−2 h−1 (N = 80) and −60.0 ± 80.2 ng m−2 h−1 (N = 59), respectively. Although the magnitudes of exchange were moderately lower than previously investigated anthropogenic sources, the overall results of this study suggest that an active landfill site can act as an important source of Hg in an urban environment along with other man-made activities.