Total mercury contamination of some fish species in the Firth of Vistula and the Lower Vistula River, Poland

The muscle tissue samples of smelt (Osmerus epelanus), herring (Clupea hare ngus), sabrefish (Pelecus cultratus), roach (Rutilus rutilus), bream (Abram is brama), ruff (Acerina cernua), perch (Perca fluviatilis), pikeperch (Sti zostedion lucioperca), flounder (Platichthys flesus), brown trout (Salmo tr utta) and burbot (Lota lota) collected in the Firth of Vistula, the Lower V istula River at the Blotnik site and the Gulf of Gdansk in May and June 199 7 have been analyzed for total mercury content. The method of mercury measu rement was flameless cold-vapour atomic absorption spectroscopy (CV-AAS) af ter wet digestion of the samples with concentrated nitric acid in a whole g lass system. The study indicated around twice higher concentrations of Hg i n fish collected from the Lower Vistula River than from the Firth of Vistul a. Total mercury concentrations for a relatively large number of the specim ens (between 12 and 41) of bream, perch, ruff, herring, flounder and pikepe rch caught in the Firth of Vistula correlated (0.05 < p < 0.01) with total body length and body weight (age) of fish. Any of the fish species examined contained mercury at concentrations exceeding 300 ng/g wet weight. Neverth eless, smelt, herring, sabrefish and ruff were the only mature specimens, w hile other fish examined were rather of small body size. An ongoing study o n mercury in the ecosystem of the Lower Vistula River will further focus on a larger number of fish species, specimens and including individuals large in body size.