Toenail, blood, and urine as biomarkers of manganese exposure.

Abstract

This study examined the correlation between manganese exposure and manganese concentrations in different biomarkers. Air measurement data and work histories were used to determine manganese exposure over a work shift and cumulative exposure. Toenail samples (n = 49), as well as blood and urine before (n = 27) and after (urine, n = 26; blood, n = 24) a work shift were collected. Toenail manganese, adjusted for age and dietary manganese, was significantly correlated with cumulative exposure in 7 to 9, 10 to 12, and 7 to 12 months before toenail clipping date, but not 1 to 6 months. Manganese exposure over a work shift was not correlated with changes in blood nor urine manganese. Toenails appeared to be a valid measure of cumulative manganese exposure 7 to 12 months earlier. Neither change in blood nor urine manganese appeared to be suitable indicators of exposure over a typical work shift.