There are around 145 million people who live in the basin of the Baltic Sea, including those living in 60 urban and industrial centers. The Baltic Sea is fed by some 200 rivers, of which oneeighth are "sewage rivers" (including the Vistula and Odra Rivers). Costly measures are required to abate pollution. The author presents types of sea pollutants as well as a detailed characteristics of the Baltic where these pollutants occur. He also widely discusses weapons dumped after the World War II (ammunition, mines, wrecks loaded with explosives, chemicals and fuel), particularly hazardous to the marine environment.