To reduce the arsenic content of the leaves and branches of an edible brown alga, hijiki Hizikia fusiforme, the Japanese traditional washing and soaking process before cooking was shown to be effective: about 32 to 60% of the arsenic was removed from the alga at room temperature. Increasing the amount of water in which the hijiki was soaked did not affect arsenic removal. On the other hand, arsenic content decreased linearly as the temperature used to wash and soak hijiki increased from 0 to 60°C. In the washed and soaked hijiki, inorganic arsenic accounts for 90% of the total arsenic and dimethylated arsenic compounds 10%. Copyright #

Sediments, as sources of microorganisms, were added to two kinds of media, 1/5 ZoBell 2216E and a solution of inorganic salts, which contained inorganic arsenic(III), inorganic arsenic(V), methanearsonic acid, dimethyl‐ arsinic acid, trimethylarsine oxide, tetramethylarsonium salt or arsenocholine. After 17 days of incubation at 20 °C, the arsenicals that had accumulated in the microorganisms were analysed by high‐performance liquid chromatography (HPLC). While the more toxic arsenicals [inorganic arsenic(III), inorganic arsenic(V), methanearsonic acid, dimethylarsinic acid] were not converted in the microorganisms, trimethylarsine oxide and tetramethylarsonium salt were considerably degraded to inorganic arsenic(V), and arsenocholine to arsenobetaine. Arsenobetaine that had accumulated in the microorganisms was extracted and confirmed by thin‐layer chromatography (TLC) and fast atom bombardment (FAB) mass spectrometry.

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