Seasonal variations in net methyl mercury production and total mercury removal in a constructed wetland

摘要

Ten parallel wetland mesocosms with four replicate experimental designswere utilized to assess seasonal variation in total mercury (THg) removal and netmethyl mercury (MeHg). Experimental designs included 1) Hg contaminated waterand sediments (MW-MS), 2) Hg contaminated water and clean sediments (MW-CS),3) clean water and Hg contaminated sediments (CW-MS), and 4) clean water andsediments (CW-CS). No seasonal variation in THg removal was observed for anyexperimental design. The designs receiving Hg contaminated water were sinks forTHg with average removal of 59±29%. In contrast, designs receiving clean waterwere least effective in THg removal (18±34%). Seasonal variation in MeHgproduction was observed for designs MW-MS and CW-MS, with values peaking inthe late spring and summer, whereas, other designs did not show seasonal variation.Sulfate and temperature were most important parameters found to drive MeHg.