The effect of seafood consumption on the assessment of occupational exposure to arsenic by urinary arsenic speciation measurements.

The determination of arsenite, arsenate, dimethylarsenic acid (DMA) and monomethylarsonic acid (MMA) in urine has been used for assessing occupational exposure to inorganic arsenic because these species were thought to be unaffected by dietary arsenic. However, this investigation reports how the consumption of certain types of seafood can lead to an increase in the amount of DMA excreted and hence an elevation in the urinary arsenic speciation total. Urine samples collected from volunteers between 4-20 hours after the ingestion of moderate-sized portions of mackerel, herring, crab or tuna, showed mean increases in the arsenic speciation totals of between 1.8 and 6.9 times compared with the levels in samples collected before the seafood was consumed. These findings have important implications in devising a biological monitoring strategy for workers exposed to inorganic arsenic.