Urinary lead levels among farmers in non-polluted areas in Japan.

Urine samples, 1163 in total, were collected in the winters of 1982 and 1983 from 132 male farmers and 1031 female farmers in 6 non-polluted areas in various parts of Japan. The urine samples were analyzed for lead concentration by means of flameless atomic absorption spectrophotometry after wet digestion followed by solvent extraction in the presence of sodium diethyldithiocarbamate. The lead concentration in urine (Pb-U; adjusted for a specific gravity of 1.016) distributed log-normally with a geometric mean (GM) of 1.81 micrograms/l (GSD = 1.99) for men (n = 132) and 2.08 micrograms/l (1.95) for women (n = 1031). No age-related changes in Pb-U were observed in either sex in the 30-79 year age range, and there was no sex-related difference in Pb-U. Analyses of female smokers together with area- and age-matched non-smokers suggested that the smoking habit would cause a significant increase in Pb-U. Comparison of the present findings with Pb-U levels published in the literature disclosed that the current Pb-levels among the Japanese population appear to be lower than the levels in Western Europe and the U.S.A.