9417321 Turekian The present-day high 187Os/186Os signature of osmium in the oceans is the consequence of weathering of continental crust. The supply of crustal Os to the oceans is primarily effected through stream transport. The main form of labile Os appears to be an adsorbed phase on stream particles. Release and mobility of Os in the estuarine environment is complex because of the processes of oxidation and reduction occurring in the estuary zonally and with depth in the sediment which act to sequester and release Os. Anthropogenically mobilized Os, with a characteristically non- crustal value of 187Os/186Os of about 1, has been identified in a study of New Haven Harbor and transport from this site eastward about 15km has been documented. The extension of the study to Long Island Sound and the Hudson River using the comparable anthropogenic Osimprint, probably from hospital waste from New York City, will provide a measure of the mobility of Os in estuaries and the flux to the open ocean. Preliminary results indicate the feasibility of such a study, the details of which are described in greater detail in the following pages.
