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Arsine is one of the most potent hemolytic agents. It is important to clarify arsine metabolism as well as its chemical interactions with biological components. The aim of the present study was to clarify arsine metabolism by arsenic speciation analysis in serum and urine from an acute poisoning patient with hematuria, anemia, and renal and liver dysfunction. Speciation analysis of arsenics in serum and urine was performed using HPLC-ICP-MS. The total arsenic (T-As) concentration in serum was 244.8 μg/l at admission and 97.1 μg/l at discharge. In the speciation analysis, four kinds of As compounds derived from arsine metabolism were detected in serum and urine. The concentration of arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in serum at admission were 45.8, 5.2, 17.9 and 9.3 μg/l, respectively. The concentrations of AsIII, AsV, and MMA decreased with biological half time (BHT) of 30.1, 43.0, and 96.3 h, respectively. Only DMA was increased at discharge. The urinary AsIII, AsV, MMA and DMA concentrations were 223.0, 12.1, 317.5 and 1053.5 μg/l at discharge, and decreased with BHT of 15.1, 20.8, 14.7, and 16.0 d, respectively. The results indicate that arsine was quickly metabolized to AsIII and subsequently up to DMA, with the result that the toxic effects of inorganic arsenic were added to those of arsine toxicity.

Seaweed contains large amounts of various arsenic compounds such as arsenosugars (AsSugs), but their relative toxicities have not yet been fully evaluated. A risk evaluation of dietary arsenic would be necessary. After developing an arsenic speciation analysis of wakame seaweed (Undaria pinnatifida), we conducted a wakame ingestion experiment using volunteers. Five volunteers ingested 300 g of commercial wakame after refraining from seafood for 5 days. Arsenic metabolites in the urine were monitored over a 5-day period after ingestion. Total arsenic concentration of the wakame seaweed was 34.3 ± 2.1 mg arsenic/kg (dry weight, n = 3). Two AsSugs, 3-[5′-deoxy-5′-(dimethyl-arsinoyl)-β-ribofuranosyloxy]-propylene glycol (AsSug328) and 3-[5′-deoxy-5′-(dimethyl-arsinoyl)-β- ribofuranosyl-oxy]-2-hydroxypropyl-2,3-dihydroxy-propyl phosphate (AsSug482) were detected, but arsenobetaine, dimethylarsinic acid (DMA), monomethylarsonic acid, and inorganic arsenics (iAs) were not detected. The major peak was AsSug328, which comprised 89% of the total arsenic. Approximately 30% of the total arsenic ingested was excreted in the urine during the 5-day observation. Five arsenic compounds were detected in the urine after ingestion, the major one being DMA, which comprised 58.1 ± 5.0% of the total urinary arsenic excreted over the 5 days. DMA was believed to be metabolized not from iAs but from AsSugs, and its biological half-time was approximately 13 h.