ASSESSMENT OF EXPOSURE TO INORGANIC ARSENIC BY DETERMINING THE ARSENIC SPECIES EXCRETED IN URINE

Urinary concentrations of inorganic arsenic metabolites (As-III, As-V, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)) and occ upational exposure to arsenic were measured in 24 copper smelter and a rsenic trioxide refinery workers during a study period consisting of 2 pairs of work days and the 6 (partly 4) days off between them. The co rrelations between the time-weighted average (TWA) concentrations of a rsenic in air (0.8-45 mu g/m(3)) and the concentrations of arsenic spe cies in urine 0, 0-8, 8-16 and 16-20 h after the exposure were calcula ted. The best correlation (r = 0.78, P = 0.0001) was found for the sum of As-III and As-V concentration in urine collected between 0 and 8 h after the exposure. The DMA concentrations at any time in urine corre lated only poorly to the exposure. A reason for this was obviously an increased urinary excretion of DMA due to the ingestion of DMA in the diet. An 8-h TWA exposure of 10 mu g As/m(3) was calculated to lead to an inorganic arsenic concentration of 5 mu g/l in urine.