Impact of toxic metal pollution on surface water pollution: a case study of Tohma stream in Sivas, Turkey

Abstract

This study was executed to investigate the acidification and heavy metal (Cr, Mn, Fe, Ni, Cu, Zn, and Pb) pollution of Tohma stream flowing near Kangal lignite-fired thermal power plant located in Kangal district of Sivas province in the Central Anatolia region of Turkey. All water samples were screened for pH to evaluate the acidification of the Tohma stream. Water samples were found in moderately alkaline according to pH values (8.1–8.7). The average concentrations of Cr, Mn, Fe, Ni, Cu, Zn and Pb in water samples from the Tohma stream were determined as 0.94, 2.27, 13.78, 1.24, 1.98, 0.32 and 0.54 mg L−1 using energy dispersive X-ray fluorescence spectroscopy, respectively. Metal pollution index (MPI) and metal evaluation index (MEI) were estimated to evaluate the pollution of Tohma water samples with heavy metals. The values of MPI and MEI varied from 312 (medium pollution) to 9715 (high pollution) with an average of 4713 (high pollution) and 181(medium pollution) to 317 (high pollution) with an average of 226 (medium pollution), respectively. The results of MPI and MEI revealed that investigated water samples are seriously polluted with toxic heavy metals and inadequate for drinking and irrigation water utilisation.