Total mercury concentrations in human hair from 13 countries in relation to fish consumption and location.

Five hundred and fifty nine samples of human head hair from 32 locations in 13 countries were analysed for mercury. Tests of different techniques for cleaning and storing samples showed that at ambient air mercury concentrations contamination of samples is undetectable. Arithmetic mean mercury concentrations for people who ate fish 1-4 times each month were: Australia, 2.5 ppm; Canada, 1.2 ppm; China, 0.9 ppm; West Germany, 0.5 ppm; Hong Kong, 3.0 ppm; Italy, 1.5 ppm; Japan, 3.9 ppm; Monaco, 1.7 ppm; New Zealand, 1.3 ppm; Papua New Guinea, 1.8 ppm; South Africa, 1.9 ppm; U.K., 1.6 ppm and USA, 2.4 ppm. The differences are believed to be due to diet and environment. Mean hair mercury concentrations were significantly different for the group that ate fish once or less a month (1.4 ppm) once a fortnight (1.9 ppm) once a week (2.5 ppm) and once or more a day (11.6 ppm). Simplified models of mercury pathways in the environment and man are presented. Hair mercury concentrations measured here and those reported in the literature suggested that the weighted mean hair mercury concentration of people living in both northern and southern hemispheres at latitudes greater than 40 degrees had hair mercury concentrations which were significantly lower than at other latitudes, even in industrialized countries. It is suggested that lower soil temperatures could retard mercury volatilization and inhibits its movement into pathways which get back to man.