Determination of blood and urine manganese (Mn) concentrations and the application of static sensography as the indices of Mn-exposure among Mn-refinery workers.

Early detection of neurophysiological abnormalities is believed to be most effective for the early diagnosis of chronic manganism. The static sensography was applied during the periodical health examination and the significance of total distance of the postural sway (i. e. postural sway index) as a neurophysiological index was studied in relation to the blood and urine manganese concentrations. Sixty-six workers in a manganese (Mn)-refining factory, aged 29-59 (mean 47) years, were examined from 1984 to 1989. Mn-exposed workers had been engaged in alternating shifts and the mean duration of Mn exposure was 22.6 years before the health examination in 1984. Air-borne dust and Mn levels in the working environment were 0.07-2.74 mg/m3 and 0.02-0.46 mg/m3. The mean values of the parameters in Mn-exposed workers fluctuated as follows: blood Mn concentrations 19.1-26.9 micrograms/l [control; Mean 17.8 (Standard deviation 5.2) micrograms/l], urine Mn concentration 2.60-4.22 micrograms/g Creatinine [control; Geometric mean 1.16 (Geometric standard deviation 1.93) micrograms/g Creat.] and postural sway index 51.4-94.6 cm/30 sec [control; Geometric mean 59.7 (Geometric standard deviation 1.4) cm/30 sec.]. Although there were no significant correlations between the postural sway index and blood and urine manganese concentrations, the usefulness of this kind of simple neurophysiological test should be further investigated in combination with other established examinations.