Impact of the coal fired power plants on two rivers in Bulgaria

This paper presented the effect of the activity of the coal fired power plants „Republika” and „Bobov dol” in Bulgaria and the influence of the wastewaters discharge on the ecological status of Razmetanitsa River (Struma River catchment – West Aegean region) and Sokolitsa River (Maritsa River catchment, East Aegean region). The data of the biological quality elements macrozoobenthos, phytobenthos and fish fauna; basic physicochemical parameters, dissolved oxygen, oxygen saturation, conductivity, biological oxygen demand, ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, orthophosphates as phosphorus, total phosphorus, calcium (calcium carbonate hardness), total suspended substances; specific pollutants - iron, manganese, copper, zinc, aluminum, chromium total, arsenic, free cyanides, polychlorinated biphenyls, phenols, uranium, radium-226, total α-activity, total β-activity, etc.; sulphates, chlorides; the priority substances cadmium, lead, mercury and nickel from Annex 1 of Directive 2013/39/EU were reviewed and assessed for monitoring sites before and after the discharge points from coal fired power plants in the Struma and Maritsa catchments during the period 2013-2022. A relation between the worsened biological quality elements, the exceeded values of the monitored basic physicochemical parameters and the exceeded environmental quality standards of the specific pollutants and the deterioration of the ecological status of the observed surface water bodies was established.