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18
CH3041
MERCURY IN THE
AMAZON
• In the
1970s Au was found in Brazilian Amazon in soils and river
sediments.
• Each year 100s of tons of Au are mined.
• Au is concentrated first using gravity
& then Hg is added to form an amalgam.
& then Hg is added to form an amalgam.
• The amalgam is roasted to remove the
Hg (as vapour) leaving the gold.
Hg (as vapour) leaving the gold.
• In the region 100t/y of Hg are released.
• The background air in dealers shops
goes up to 300mg/m3 (normal 3ng/m3) which
is well beyond the WHO limit of 1mg/m3.
goes up to 300mg/m3 (normal 3ng/m3) which
is well beyond the WHO limit of 1mg/m3.
• Sediments are contaminated, the
tropical
conditions are excellent for biomethylation
and plants and animals have elevated [Hg].
conditions are excellent for biomethylation
and plants and animals have elevated [Hg].
