URINARY LEVELS OF INORGANIC AND ORGANIC ARSENIC METABOLITES AMONG RESIDENTS IN AN ARSENIASIS-HYPERENDEMIC AREA IN TAIWAN

In order to elucidate whether urinary levels of inorganic and organic arsenic metabolites are associated with previous exposure to high-arse nic artesian well water, a total of 302 residents of age 30 yr or olde r were recruited from three arseniasis-hyperendemic villages in Taiwan . Most study subjects had stopped consuming high-arsenic artesian well water for more than 20 yr. The mean total arsenic (As-t) determined b y inductively coupled plasma mass spectrometer (ICPMS) was 267.05 +/- 20.95 mu g/L, and the mean level of inorganic arsenic and its metaboli tes (As-i) was 86.08 +/- 3.43 mu g/L. In the multivariate analysis, ur inary dimethylarsinic acid (DMA) levels were significantly inversely a ssociated with age, with women exhibiting significantly lower urinary amounts of arsenite [As(III)], arsenate [As(VI)] monomethylarsonic aci d (MMA), organic arsenic (As-o), and As-t compared to men. After adjus tment for age and sex, previous cumulative arsenic exposure through co nsumption of artesian well water was significantly associated with ele vated urinary levels of MMA and DMA, but not As(III) + As(V), As-o, an d As-t. In the multivariate analysis, the percentage of As-o in As-t w as significantly higher in men than women, but this was not significan tly associated with age. The percentage of As(III) + As(V) in As-i inc reased significantly with age, while the reverse was noted with DMA in As-i. Women had a significantly higher DMA percentage but lower As(II I) + As(V) and MMA percentages in As-i than men. After adjustment for age and sex, the percentages of As(III) + As(V) in As-i. were signific antly inversely associated with previous arsenic exposure through cons umption of artesian well water. Data suggested that women seem to poss ess a more efficient arsenic methylation capability than men, and agin g diminishes this methylation capability; furthermore, the higher the cumulative arsenic exposure, the greater is the body burden of inorgan ic arsenic, mainly in the form of MMA and DMA.