Assessment of mercury contamination based on mercury distribution in sediment, macroalgae, and seagrass in the Todos os Santos bay, Bahia, Brazil.

The Todos os Santos bay (TSB) is the second largest Brazilian bay. Despite the large number of potential anthropogenic sources of mercury (Hg) in the bay, data on this element in this marine environment are very scarce. Total Hg concentrations were therefore determined in sediment, macroalgae, and seagrass species collected during dry and rainy seasons, from eight locations. In ~45 % of the sediment samples, Hg concentration was two to four times higher than the upper value considered the regional Hg background (15 μg kg(-1)). Geoaccumulation index indicated that Hg contamination was at none to heavily contaminated. In Padina sp., Caulerpa sp., Hypnea sp., and Halodule wrigthii, Hg concentrations ranged from 10.61-297.61, 15.59-74.50, 12.84-158.03, and 4.02-67.25 μg kg(-1), respectively.