Role of the River So a in transfering mercury compounds into the gulf of Trieste

In presented work different mercury forms in inflow of River So~a at mixing zone between fresh and sea water have been investigated. Regarding to River So~a water regime three sampling periods have been proposed at nine sampling locations.Total Hg concentrations were between 4.5 and 174 ng/l with average value of 25.9 ng/l. Most Hg (72%) was bounded to suspended matter. The highest values in water column were measured in May when the average total Hg concentration was 33.6 ng/l. Methylmercury(MeHg) concentrations were in wide range between 12.0 and 1350 pg/l (average 175 pg/l). Most MeHg was in dissolved form (85%). Dissolved Hg (DGM) concentration in water was between 0.03 to 2.6 ng/l. More than ten years after closure of the mercury mine in Idrija concentrations of different Hg species in River So a remains very high.