Formation of volatile selenium species in synthetic seawater under light and dark experimental conditions

Experiments were performed in the laboratory on synthetic seawater spiked w ith different selenium species at trace levels to study the formation of vo latile selenium compounds under dark or controlled simulated sunlight condi tions, Spiking the reaction media with inorganic and organic selenium compo unds demonstrated that several volatile selenium species could be formed un der these simulated conditions. Selenoamino acids react to produce signific ant amounts of volatile selenium species in both light and dark conditions, Products formed include dimethyl selenide (DMSe), dimethyl selenyl sulphid e (DMSeS) and dimethyl diselenide (DMDSe). Inorganic selenium oxyanions add ed to the synthetic reaction media did not form volatile species via abioti c reactions despite the presence of strong methylating agents. These result s suggest that the formation of stable volatile species from bio-organic se lenium compounds can occur via abiotic reactions in the marine photic zone. Copyright (C) 2000 John Wiley & Sons, Ltd.