Cadmium concentrations in coals and fly ashes from coal fired thermoelectric power plants in Bulgaria

The goal of the present study is to present new data regarding concentration and distribution of Cd in feed coals and fly ashes from seven Bulgarian coal fired thermoelectric power plans (TPPs). The study was performed on feed coals and fly ashes collected from Maritza East 2, Maritza East 3, Maritza 3, Republika, Bobov Dol, Varna and Russe TPPs. Bulk fly ash from Maritza East 2 and Maritza East 3 TPPs were obtained and fly ashes from each row of electrostatic precipitators (ESPs) of Maritza 3, Republika, Bobov Dol, Varna and Russe TPPs were also collected. Feed coals from bunkers were sampled at each TPPs. The Cd was determined by using ICP-MS. The present investigation shows that the concentration of Cd in studied coal and fly ashes from almost all TPPs is around the average or lower than Cd content in comparison with Clark values. The exceptions are the fly ashes from the 2-nd and 3-rd row of ESPs from Maritza 3 TPP, where up to 2.5 times higher Cd content was registered. This study shows that Cd concentration in fly ashes gradually increases from the 1st to 3rd and 5th-row of ESP from almost all sampled thermoelectric power plants, whence the conclusion that Cd content increases significantly and is mainly concentrated in the finest fly ash particles.