Mercury in urine.--Sex, age and geographic differences in a reference population.

The urine of 103 inhabitants from Hadeland and 240 persons from Odda, Norway, was examined with respect to the content of mercury and creatinine. Odda is a small community in a narrow fiord on the western coast of Norway. The sea water is polluted with mercury and other heavy metals emitted from a zinc smelter. Hadeland is a less industrialized county in the eastern part of Norway without any known inorganic mercury contamination of the external environment. None of the participants of the study were occupationally exposed to mercury. The mercury excretion was significantly higher among people living in Odda and highest among those living close to the zinc smelter. This finding probably reflects a contamination of the external environment. Women in Odda and Hadeland had a higher mercury excretion than the males of the respective regions. Mercury excretion also seemed to be age-dependent in that there was a gradual reduction in mercury excretion with advancing age. Although there seem to be age- and sex-dependent differences with respect to mercury excretion, 100 nmol of mercury/1 of urine and 10 nmol of mercury/mmol of creatinine are suggested as upper limits for "normal" mercury excretion among non-occupationally exposed persons living in Norway.