Assessing mercury contamiantion in the Amazon


Anthropogenic activities, such as gold mining and soil erosion, seem to play an important role in the recent enrichment of mercury to aquatic sediments of the Amazon. Soil erosion may have a more regional effect, while the effects of gold mining are more local.
Interestingly, the hydrographic basin of the Amazon has a very high methylating capacity for mercury. The highest methylating capacities are found in floating macrophyte mats.
Riverine humans in the Amazon are exposed to methylmercury through the ingestion of contaminated fish. Hair mercury levels in riverine human populations are commonly above 10 µg/g, which is the threshold limit for adverse neurological effects to the fetus.
Finally, hair mercury concentrations in riverside human populations were predicted from mercury concentrations in fish and compared to observed hair mercury concentrations. The results indicate that human exposure to methylmecrury, is associated with the ingestion of methylmercury contaminated fish.

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