Environmental characterization of potential mercury contamination in two indigenous communities in Suriname, South America

In Suriname, mercury (Hg) is released into the environment through gold mining activities. Hg is biogeochemically cycled through a methylation process that converts inorganic Hg into methyl-mercury and is biomagnified in aquatic food chains from bacteria to piscivorous fish. Indigenous populations rely on fish as a major component of their diet and are potentially chronically exposed through consumption of mercury-tainted fish. Characterization of the key environmental parameters that contribute to Hg exposures in indigenous communities and assessment of the contribution of diet as an exposure route for Hg contamination are the primary research aims. Two communities located downriver from gold mining activities were identified as study populations. Dietary surveys were administered at each village and environmental samples (river water, hydro-soil, and piscivorous fish) were collected and analyzed for Hg. The dietary surveys indicated that 90% of the study population consumed fish at least once a week; however, for approximately 65% of the study population fish was a component of their daily diet. Hg measured in the river water ranged from non-detectable to 0.03 ug Hg/L. Hg in the hydrosoil ranged from 0.14 to 0.35 ug Hg/g. Hg levels in fish ranged from 0.17 to 1.64 ug Hg/g. The levels of Hg in 75% of the fish samples collected are at or above the WHO standard set at 0.5 ug Hg/g. The data gathered from both the dietary survey and the analyses of the environmental samples provide insight on the overall magnitude of Hg exposure and health risks.