Land-based sources of pollution along the black sea coast of Turkey: Concentrations and annual loads to the black sea

Abstract

Concentrations of inorganic pollutants, pesticides and PCBs were measured in 42 sources including rivers, streams, and industrial and domestic discharge points along the Turkish Black Sea coast in three seasons of the year 1993. The measured concentrations were compared with water quality standards currently effective in Turkey in order to determine the levels of pollution in the rivers and streams. Concentrations were also combined with the water discharge data to determine annual loads of pollutants discharged from each source into the Black Sea. Concentrations of measured parameters were much higher in domestic and industrial discharges, as expected. Most of the rivers and streams were polluted with organic material, nitrogen and phosphorous species due to discharges of untreated domestic wastes into these streams. Metal concentrations measured in the rivers and streams were fairly low due to the lack of extensive industrialization in the drainage areas of the streams. Some of the small streams, including the Neyren, Kilimli, Zafir and Tabakhane streams, are heavily polluted and were identified as sources having the potential to generate hot spots along the coast. Annually, a total of 39.700 tons of nitrogen, 3.700 tons of phosphorous, 15 tons of Cd, 340 tons of Cu, 60 tons of Pb, 1.200 tons of Zn, 12 tons of heptachlor, 11 tons of aldrin, 31 tons of dieldrin, 180 tons of endrin and 500 tons of DDT are discharged from Turkish sources into the Black Sea. Except for trace metals, rivers and streams dominate the flux of pollutants. Large industries along the coast that discharge their wastes directly to the Black Sea account for a significant fraction of the annual metal discharges. Pesticides and PCBs were detected in most of the sources included in the study indicating their illegal use in agriculture. The Sakarya river was the most important source of pesticides.