The Role of Sedimentary Organic Carbon and Nitrogen in the Distribution of Mercury in the Gulf of Trieste (Northern Adriatic Sea)

摘要

Biogeochemical processes involving mercury compounds in aquatic environments are of great importance especially in areas where mercury inputs are particularly high, as in the case in the Gulf of Trieste (northern Adriatic Sea). In this study, stable isotope data were used in order to determine the role of sedimentary organic carbon and total nitrogen in the distribution of Hg species. The results show that the major source of inorganic mercury is the river Isonzo, from which mercury is transported into the Gulf, and adsorbed onto particles, while the major source of methylmercury is the bottom sediment of the Gulf itself. Terrigenous nitrogen seems to be involved in the transformation processes of methylmercury in sediments.