[Mercury in muscle tissue of flounder Platychthis flesus from two sites in the Gulf of Gdansk].

Total mercury concentration was determined in the muscle tissue of flounder collected under Stegna (ca. 1 mile east of the Vistula River outlet) and under Gdynia (ca. 12 miles northwest of the Vistula River Outlet) sampling sites in the Gulf of Gdańsk in 1992 and 1993. The method of measurement was cold-vapour atomic absorption spectrometry (CV-AAS) after wet digestion of the samples with concentrated nitric acid. The arithmetic means of mercury concentration in muscle tissue of flounder collected under Stegna were 46 +/- 24 in 1992 and 57 +/- 47 in 1993, while for those under Gdynia 20 +/- 19 and 26 +/- 18, micrograms/kg on a wet weight basis, respectively. Mercury concentrations in muscle tissue of flounder collected under Stegna were positively correlated with the body length and body weight of fish (0.05 < p < 0.001), while in the case of specimens collected under Gdynia no such relationships were found. These observations seem to imply that Vistula River is an important source and pathway of mercury entrance into the Gulf of Gdańsk.