The mercury content of hair of Japanese immigrants in various locations in South America.

Hair mercury levels in four Japanese immigrant settlements in South America were determined by cold-vapor atomic absorption spectrometry. The levels in the two Bolivian settlements were relatively higher (6.22 and 3.53 ppm for males, 3.66 and 2.23 ppm for females) than those in Brazil (2.19 ppm for males, 1.57 ppm for females) and in Paraguay (2.40 ppm for males, 2.04 ppm for females). The levels in Bolivia were almost the same as recent Japanese levels. Dose-response relationships between frequency of eating fish and hair mercury level were found in all the settlements. However, even in the same fish-eating category, the content varied from place to place. Significant correlations between husbands and wives were demonstrated in three out of four settlements. These results imply that the mercury content of hair is regulated by the life style within each family. That is, inhabitants of Japanese settlements, especially in Bolivia, maintain their Japanese habit of fish eating. This results in a high hair mercury content, even when they live in a rural area and consume only fish from the head rivers of the Amazon.