Bottom sediments in a polluted marine environment,upper Saronikos Gulf,Greece

The domestic and industrial waste water from most of the greater Athens, Greece area is discharged into shallow water at the upper end of the semi-enclosed Saronikos Gulf. The lack of circulation and excess organic matter has led to the formation of a rapidly expanding sludge field. Black anoxic sediments high in organic carbon now cover almost 9 sq km of sea floor and contain high concentrations of heavy metals. Maximum increases above background values range from 22× for mercury, 1500× for arsenic, 1200× for chromium, to 3000× for zinc. The principal sources of metals are 1) a fertilizer factory, 2) the Athens sewer outfall, and 3) the industries in eastern Elefsis Bay.