摘要：1) The mercury content in the hairs of normal persons, who resided in Japan and other countries, was estimated by dithizone, method. 2) The average value obtained from 73 different samples taken from residents in Japan was about 6 ppm, and that of 30 samples from several other countries was about 2 ppm. 3) The mercury content in the hairs of Japanese students, who stayed abroad for over 1.5 years, was almost same as the average value of native population. 4) After returning to Japan, the mercury content in the hairs of these students gradually increased and restored to the value of residents in Japan at the end of one or two years. 5) The difference and the gradual increase of mercury content in the hairs, therefore, may depend on residential environments.
