The state of the marine environment on a global scale as well as the status of each marine ecosystem is threatened by the emission of a wide range of organic compounds and metals.The occurrence of relatively high concentrations of these pollutants in the Baltic Sea is mainly caused by the constant inflow of river water.Inland location and the Baltic hydrological regime impede the exchange of water from the ocean,which is why marine organisms are constantly exposed to the harmful effects of human impact on the environment.Despite a number of projects undertaken,both organizational and technological,to reduce the amount of xenobiotics into the environment,the problem is still present due to the high stability of certain pollutants or their degradation products.Grey seals as the final link in the food chain in the Baltic Sea,as well as due to the long life and a long biological half-life of toxin elimination are likely to accumulate in their tissues significant amounts of a variety of ksenobiotics.These aspects attempt to assess their ability as a bioindicators of contamination degree in the Baltic Sea.The objective of the studies was to measure the levels of elements in the liver samples of grey seal(Halichoerus grypus).The samples were obtained from the Environmental Specimen Bank located at the Museum of Natural History in Stockholm(Sweden)and the Marine Station of the Institute of Oceanography at the University of Gdansk in Hel.The project was focused on seals from three areas of the Baltic Sea(Northern,Central and Southern).Seals were caught or shot beteween 2006 and 2010.The liver samples were analyzed for such elements like Al,B,Ba,Cd,Co,Cr,Cu,Fe,Ga,Li,Mn,Mo,Ni,Pb,Se,Si,Sr,Tl,V,Zn,Ca,K,Mg,Na and REE with the use of mass spectrometry coupled with an inductively coupled plasma(ICP-MS).Total mercury content was determined by cold-vapor AAS technique at 253.7 nm wavelength.Geographical variation in bioaccumulation were found for such elements like As,B,Cu,Ni,Rb,Sr,Tl with higher concentrations for most of these elements in samples of the seals from Southern Batic.Accumulation with age of the seals was found for Ag,B,Bi,Cd,Co,Hg,Mo,Sb,Se,Sn,V and Zn and the rare earth elements(REE).