At the village of Kikretum, in the Kayapo' Indian Area in the south of
the state of Para', children are subject to mercury pollution even before they
are born. Mercury, a highly toxic heavy metal, capable of causing
irreversible neurological damage and birth defects, is used extensivly by
gold miners in the Amazon region. When released into the rivers mercury gets
into the food chain, and the Indians are contaminated by eating fish. Mercury
poisoning is then passed from mother to child during pregnancy.
A study conducted by Antonio Barbosa, a chemist from the University of
Brasi'lia, confirmed that new-born kayapo' children suffer from high levels of
mercury contamination. This study showed that mercury levels in kayapo' women
drop significantly during pregnancy, as the mercury is transferred from the
mother to the fetus. It is for this reason that new-born children show higher
levels of mercury contamination than their mothers. The contamination is
further compounded during breast-feeding. The study examined 75 people,
including women of child-bearing age, pregnant and nursing women, and their
children.
Tests on one of the Kayaps women in the study showed levels of 14.5 ppm
(parts per million) of mercury at the beginning of her pregnancy; 9.5 ppm in
the third month; 6 ppm in the sixth month; 7.3 ppm immediately after delivery;
and 15 ppm three month later. Concentrations of mercury above 10 ppm
constitute a health hazard, according to the World Health Organization
(WHO).
At the gold mines mercury is mixed with river gravel to extract the gold.
The gold amalgamates with the mercury and can thus be separated from the
gravel. The mercury is then burnt off and the gold remains. The technique is
simple and cheap, but mercury is a toxic and non-degradable pollutant. Based
upon figures for Brazilian gold production, the Centre for Mineral
Technology (CETEM) estimates that 140 tons of mercury are used each year by
the gold miners of the Amazon region. Of this mercury, 20% finds its way
directly into the rivers, while the remaining 80% is relaeased into the
atmosphere. Once in the water mercury tends to accumulate in the tissues
of living animal and plant species.
According to Antonio Barbosa the levels of mercury found among kayapo'
children are not as yet critical, but they are cause for concern, especially
since mercury continues to be discharged into the rivers of the kayapo'
Indian Area. Furthermore, the effects of mercury poisoning are not usually
manifested immediately at the birth of a child, but may become evident
after the sixth month of life.
Brasi'lia, 28th October 1994
Cimi - Indianist Missionary Council