EXTRACTION STUDIES OF HEAVY-METAL POLLUTANTS IN SURFICIAL SEDIMENTS FROM THE SOUTHERN BALTIC SEA OFF POLAND

Surficial sediment samples from the Gulf of Gdansk and the southern Baltic Sea were analyzed for Cu, Zn, Cd, Pb, Ag, Cr, Co, Ni, Mn, Cs, Rb, Fe, Ca, Mg, K, Na, Li, Sr, Al and P. Extraction techniques were used to establish the association of the elements with specific phases in the sediments. Elimination of grain size effects was achieved by analyzing the size fraction < 80 mu m. Three chemical fractions of the elements were determined using various leaches, i.e. 1 M HCl, 0.1 M NaOH as well as a mixture of concentrated HNO3 and HClO4. 1 M HCl leached > 60% of the total Zn, Cd, Pb and Na, similar to 60% of the Cu, Cr, Mn, Sr, Ca and Mn, and < 50% of the Ag, Co, Ni, Cs, Rb, Li, Fe, Al, K and P in the sediment. Up to 45% of the total Cu was extracted from the sediments by 0.1 M NaOH and appears to be associated with the humic acid fraction. Areal variations of element contents were observed. Most elements in total and HCl leachates were enriched in sediments from near the mouth of the Vistula River. Correlation studies indicated that the trace elements are partitioned among several phases such as Fe- and Mn-oxyhydroxides and clay minerals in the sediments.