Methylmercury in the Gulf of Trieste (Northern Adriatic Sea): From Microbial Sources to Seafood Consumers

The Gulf of Trieste (northern Adriatic Sea) is one of the most mercury-polluted areas in the Mediterranean and in the world due to the past mining activity in the Idrija region (western Slovenia). The link between microbial production of toxic methylmercury (MeHg), and its bioaccumulation and biomagnification in marine food webs of the gulf is at present rather poorly characterized but is critical to understanding the links between sources and higher trophic levels, such as fish, that are ultimately vectors of human and wildlife exposure. This overview explores three major topics: (i) the microbial biogeochemical cycling of Hg in the area, (ii) the trophic transfer and bioaccumulation of MeHg in pelagic and benthic marine food webs, and (iii) human exposure to Hg through marine fish and shellfish consumption. These are important goals since the Gulf of Trieste is an area of great economical importance.