Mercury exposure and ecosystem
health in the Amazon: Building
solutions with the community
University of Quebec in Montreal
Federal University of Pará
Federal University of Rio de Janeiro
Riverside villagers of the Rio Tapajós
Local authorities and NGOs
funded by International Development Research Centre
(IDRC), Canada
WSSD, Johannesburg, 2002
Mercury
Mercury contamination
contamination in
in the
the
Amazon
Amazon
Š
High levels of mercury in fish
Š
High levels of mercury in human
populations
What did we learn?
Gold-mining
Deforestation
Mercury released into the aquatic environment
Accumulated in the trophic chain
WSSD, Johannesburg, 2002
Fish eaten by humans
Mercury in fish
Š Carnivorous fish have high levels of mercury
(half were over the recommended limit: 0.5
ppm)
Š Herbivorous fish have very little mercury
WSSD, Johannesburg, 2002
Mercury in humans
Š Mercury in villagers’ hair increased with the
number of fish meals:
`Higher among those who ate fish daily
`Higher among those who ate more carnivorous fish
`Varied seasonally with the bioavailability of fish
WSSD, Johannesburg, 2002
Was this affecting health?
Early
nervous
system
changes
?
Subclinical
neurological
signs
Minamata
Disease
(50 ppm)
Increasing mercury exposure
WSSD, Johannesburg, 2002
Dexterity
Sensitive
tests
Fine movements
Vision
Results consistent with mercury
poisoning
Š Decrease in motor, tactile and visual functions
with increasing hair mercury levels;
Š Neurological exam normal with the exception of
disorganised coordinated movements which
increased with increasing mercury
WSSD, Johannesburg, 2002
Building solutions
Š Short term: Fish- eating practices: Maximize
nutrition and minimize toxic risk
Š Medium term: Identify ‘hot spots’ for
methylation
Š Long term: Regional Agroforestry practices
WSSD, Johannesburg, 2002
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Mercury exposure and ecosystem health in the Amazon