Further evidence for a drastic decline of potentially hazardous trace metals in Baltic Sea surface waters

We present results of a Baltic Sea surface water study on selected dissolve d trace metals (<0.4 pm) in which we compare our 'historical' data of 1982 with measurements obtained from samples collected in 1995 in the same area. The methods of collection, storage and analysis followed the same procedur es with the exception of Zn, Between 1982 and 1995, significant concentrati on decreases have been observed for Pb (approximate to 73%), Cd (approximat e to 66%), Zn (approximate to 23%), Cu (approximate to 19%) and Ni (approxi mate to 18%) in the Baltic proper, Concentration decreases of 5-6% yr(-1) f or Cd and Pb, and 1.4-1.8% yr(-1) for Ni, Cu and Zn have been observed in t he Bornhom and Gotland Seas, We attribute these changes to reduced input fr om river, waste waters, and atmospheric deposition. The study also reveals that shortterm or seasonal variations in the concentrations of these elemen ts are small in Baltic surface waters. In contrast, strong seasonal variati ons of Mn are observed in open Baltic surface waters. (C) 2000 Elsevier Sci ence Ltd, All rights reserved.