DETERMINATION OF CHEMICAL-SPECIES OF IODINE IN SOME SEAWEEDS .1.

The chemical species of iodine in seven marine algae Codium fragile, U lva pertusa, Monostroma nitidum, Gracilaria confervoides, Sargassum Kj ellmanianum, Dictyopteris divaricata and Laminaria japonica were studi ed using neutron activation analysis combined with chemical separation . The contents of total iodine, water-soluble iodine, soluble organic iodine, I- and IO3- were determined. The results indicate that the che mical species and contents of iodine in various algae are remarkably d ifferent. The highest iodine content of 734 mg/kg (wet basis) was foun d in Laminaria japonica, with 99.2% of the total iodine being water so luble. The iodine contents of the other six algae are lower and solubl e iodine makes up 16-41% of the total. In the aqueous leachate, iodine is mainly I-, which amounts to 61-93% of total water-soluble iodine; the percentages of organic iodine making up 5.5-37.4%, while the conte nts of IO3- are the lowest, 1.4-4.5%. This result suggests that the me chanism of iodine enrichment is different for various algae and that i ts bioavailability varies as well. (C) 1997 Elsevier Science B.V.