Wet and dry deposition of mercury in Bermuda

Elevated concentrations of mercury (Hg) in fish from around Bermuda and fish consumers promoted a study of the atmospheric inputs of Hg to the ocean in the region. The average concentrations of total mercury in rain (THg; volume weighted mean 4.7 ng L−1) and in aerosols (particulate Hg; HgP; 9.5 pg m−3) were found to be comparable to other coastal locations removed from local sources at similar latitudes in North America. The estimated wet and dry deposition fluxes of Hg suggest that Bermuda is impacted by anthropogenic sources. A mass balance for Hg across the air–sea interface for the region around Bermuda also suggests that atmospheric wet plus dry deposition is less than estimated gas evasion of elemental Hg, indicating that the ocean is a net source in the region. This likely reflects historic elevated deposition of Hg to the North Atlantic, as has been suggested by historic water column data and from Hg biogeochemical modeling.