Pj. Lechler et al., Elevated mercury concentrations in soils, sediments, water, and fish of the Madeira River basin, Brazilian Amazon: a function of natural enrichments?, SCI TOTAL E, 260(1-3), 2000, pp. 87-96
Previous site-specific investigations have found that mercury concentration
s in water, sediments, and biota of the Brazilian Amazon are elevated above
global averages, and that these concentrations are a direct result of wide
spread mercury amalgamation mining operations conducted by non-organized pr
ospectors. In order to assess the regional impacts of Hg contamination from
these non-organized gold mining activities, water, sediments, and fish wer
e systematically collected in 1997 along a 900-km reach of the Madeira Rive
r. The sampling program extended from the Amazon River upstream to Porto Ve
lho, the site of historic and ongoing mercury amalgamation mining. Mercury
concentrations were found to be elevated above global averages in all sampl
ed media. However, the geochemical data suggest that the high mercury level
s are due largely to natural sources and natural biogeochemical processes,
and that the impacts of anthropogenically released mercury from mine sites
is relatively localized. (C) 2000 Elsevier Science B.V. All rights reserved
.