HUMAN URINARY ARSENIC EXCRETION AFTER ONE-TIME INGESTION OF SEAWEED, CRAB, AND SHRIMP

We studied chemical speciation of arsenic compounds in urine samples b y using HPLC with inductively coupled plasma mass spectrometry detecti on. We examined urinary arsenic excretion patterns and the arsenic spe cies excreted from nine human subjects who ingested seaweed products a nd crab (or shrimp). Fast urinary excretion of unchanged arsenobetaine was seen after ingestion of crab and shrimp, which contain arsenobeta ine as the major arsenic species. In contrast, the arsenosugars, which comprise the major arsenic species in seaweed, are metabolized and ha ve a longer retention time in the human body. When nine volunteers ing ested the commercial seaweed product nori, both the urinary arsenic ex cretion pattern and the excreted arsenic species varied from individua l to individual, and as many as six metabolites could be detected. It seems that arsenosugars are not decomposed by stomach acid and that re actions involving enzymatic and (or) microbial activity in the human b ody may be responsible for the metabolism of arsenosugars.