Ingestion and excretion of arsenic compounds present in edible brown algae, Hijikia fusiforme, by mice

The element arsenic is a carcinogen and toxic for humans and other living organisms. Some seaweeds contain high amounts of inorganic arsenic (iAs). In particular, Hijikia fusiforme has a high iAs content of approximately 50%. In this study, we examined the absorption, metabolism, excretion, and accumulation of arsenic compounds in mice after the administration of Hijiki. The single-dose experiment, wherein a single dose of cooked Hijiki was administered to the mice, revealed that the urinary and fecal excretion of arsenic compounds was the highest on the first day of dosing, and it became clear that 66–92% of arsenic was excreted within 3 days after administration of the first dose. The repeated-dose experiment, wherein repeated doses of cooked or dried Hijiki were adminstered to the mice, arsenic was detected in all the tissues, but only approximately 5% of the administered dose of arsenic was detected as residual arsenic. These results suggest that the arsenic present in cooked Hijiki is accumulated in very small amounts in mice.