FACTORS AFFECTING THE PHOTOCHEMICAL PRODUCTION OF CARBONYL SULFIDE INSEAWATER

Our laboratory studies indicate that the photochemical production of c arbonyl sulfide (COS) in seawater can result from the photosensitized reaction of organosulfur compounds. Because natural photosensitizers a re more prevalent in coastal waters than the open ocean, these results help to explain why marine COS concentrations are highest in coastal and shelf regions. Wavelength studies of COS photoproduction in freshl y collected seawater samples demonstrated that COS formation is induce d primarily by the UV part of solar radiation. Studies with model orga nosulfur compounds in synthetic and coastal seawater indicated that co mpounds with bivalent sulfur atoms (thiols, sulfides) react most effic iently to produce COS. We propose that the initial step of the photose nsitized reaction primarily involves attack on the sulfur atom or sulf hydryl H atom by reactive transients.