ALTERED PROFILE OF URINARY ARSENIC METABOLITES IN ADULTS WITH CHRONICARSENICISM - A PILOT-STUDY

Relationships between alterations in the profile of urinary arsenic (A s) species and the presence of cutaneous signs of arsenicism were stud ied in Region Lagunera, Mexico. The use of urinary concentrations of p utative substrates and products of the As metabolism pathway, as indic ators of metabolic efficiency is also discussed. Arsenic was determine d by hydride generation atomic absorption spectrophotometry and separa tion of As species was performed by ion exchange chromatography. The e xposed group had an average of 0.408 mg As/l of total As (TAs) in thei r drinking water, whereas 'control' individuals had 0.031 mg/l. Urinar y concentrations of arsenic species and TAs were 20 to 95 times higher in the exposed group. Significant increases in the relative proportio ns of inorganic arsenic (Asi) and monomethylarsonic acid (MMA), accomp anied by decreases of dimethylarsinic acid (DMA) were also found in ex posed individuals. Therefore, significant decreases in the value of th e MMA/As-i, DMA/MMA and DMA/As-i ratios were observed, suggesting a de creased As methylating ability. Exposed individuals bearing cutaneous signs had a significantly longer time of exposure, higher urinary conc entrations and proportions of MMA and MMA/As-i values, and significant ly lower DMA/MMA than exposed individuals without cutaneous signs. Fur ther research is needed to identify better parameters for assessing th e efficiency of As metabolism in chronically exposed populations and t o confirm the potential relationship between metabolic alterations and overt signs of As toxicity.