Mercury in the world’s largest hypersaline lagoon Bay Sivash, the Sea of Azov

There are few studies on mercury content in hypersaline waters. Mercury content was studied in Bay Sivash (the Sea of Azov), the world’s largest hypersaline lagoon with a strong salinity gradient from 36 to 90 g l −1 . The dissolved mercury compounds ranged from 120 to 250 ng l −1 , Hg varied from 60 to 450 ng l −1 in the suspended matter, and total mercury in the water ranged from 200 to 600 ng l −1 . Salinity and the total suspended matter had practically no effect on the amount of dissolved and suspended forms of mercury separately, but their growth significantly increased total mercury content in water. Only the concentration of dissolved forms of mercury in water significantly correlated with dissolved organic matter. The Hg concentration in the bottom sediments averaged 13.8 ng g −1 wet weight. Both high salinity and human activities on the Sivash drainage area are responsible for high Hg content in lagoon water.