CONCENTRATION OF MERCURY IN HAIR OF INDIGENOUS MOTHERS AND INFANTS FROM THE AMAZON BASIN

Hair mercury concentration, as an indicator of mercury body load, was studied in 251 samples of indigenous women and children living in sele cted areas of the Amazonian region, The mothers or women of child-bear ing age, either non-Indians or Indians, and their children were sample d along the Madeira River and in the Kayapo reservation (Fresco River) , respectively, Among the sampled individuals there were mothers with infants less than 2 years old, Total mercury-in hair was determined by cold vapor atomic absorption spectrometry after alkaline digestion, T he distribution of hair mercury concentration greater than 10 mu g/g o ccurred in 67.4% of non-Indian women and 25% of Indian women, overall only 1% of non-Indian women had concentrations of hair mercury above 5 0 mu g/g. In women of child-bearing age, the median and range of hair mercury concentration was 14.08 mu g/g, and 0.8-94.7 mu g/g for non-In dians, and 8.30 mu g/g, and 0.8-13.3 mu g/g for Indians. The correlati on between maternal hair mercury and mercury in hair of infants (less than 2 years of age) still breast-feeding, was statistically significa nt only for non-Indians (r = 0.555 p < 0.001). The correlation between length of breast-feeding and mercury concentration in infant's hair w as significant for Indian children (r = 0.512; p = 0.029) but not for non-Indian children (r = 0.025; p = 0.832). A subsampling of 30 mother s had segmented hair analysis that showed st mean decrease of 20% in b ody burden during pregnancy, thus indicating the extent of placental t ransference of mercury to fetuses.