Epidemiologic assessment of measures used to indicate low-level exposure to mercury vapor (Hg).

Mercury (Hg) concentrations in individual spot urine samples collected over consecutive 1-d periods were compared with Hg concentrations measured in combined 24-h urine samples from 69 practicing dental professionals with low exposure to Hg vapor (Hg) in order to validate the use of spot urine samples as an indicator of Hg exposure. The level of Hg in air as an exposure measure was also evaluated by comparing air concentrations of Hg in dental offices with both spot and 24-h urine Hg levels. The results showed: (1) There was little diurnal variation (approximately 9%) in urinary Hg values; (2) a strong correlation (R2 = .