BIOLOGICAL MONITORING OF OCCUPATIONAL EXPOSURE TO ARSENIC BY DETERMINING URINARY CONTENT OF INORGANIC ARSENIC AND ITS METHYLATED METABOLITES

A study was undertaken to assess the relationship between inhalation e xposure to arsenic in copper smeltery workers and urinary excretion of total inorganic arsenic metabolites (Asitm), including inorganic arse nic (Asi), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) . The methods applied made it possible, in principle, to determine all forms of airborne arsenic and to eliminate the influence of seafood-d erived organoarsenicals on the level of urinary Asitm. Air samples wer e collected on the second day of work after the weekend break. Urine s amples were collected just after shift-end on the same workday. The ti me-weighted average (TWA) concentrations of arsenic in the workers' br eathing zone varied between 1 and 746 mu g/m(3) and Asitm concentratio ns in urine between 2 and 850 mu g/l (s.g. 1.024). The urine samples w ith a specific gravity of lower than 1.010 and higher than 1.030 were not considered; neither were those subjects with an Asitm excretion ef ficiency of higher than 100% of the dose absorbed during the day of me asurement. In total, 53 air samples and corresponding urine samples we re obtained. The correlation coefficient between the airborne arsenic concentration in mu g/m(3) (X) and the concentration of urinary Asitm in mu g/l, s.g. 1.024 (Y), was 0.723. The relation between the two var iables can be presented using the following formula: Y = 6.29 . X-0.61 6 According to the findings of this study, as well as the results of t hree other studies based on similar principles, the daily exposure to arsenic concentrations of 10 mu g/m(3) and 50 mu g/m(3) led to concent rations of Asitm in urine of about 30 mu g/l and 70 mu g/l (s.g. 1.024 ), respectively.