Assessment of heavy metal pollution of urban soils of Batman by multiple pollution indices

Heavy metal accumulation is observed in urban soils, sometimes due to anthropological effects and sometimes due to natural geological units. In order to determine the heavy metal content of the Upper Miocene-Lower Pliocene Selmo Formation, which is observed in the whole study area and consists of conglomerate, sandstone and silt stone, soil and river sediment samples were taken. Within the scope of pollution assessment, geo-accumulation index (Igeo), enrichment factor (EF) and pollution index (PI) calculations of Batman urban soil samples were made and different degrees of pollution values were determined. High pollution values were obtained for As, Mo and Sb elements in all pollution indices calculated. The pollution levels of the three elements were determined as strongly to extremely contaminated according to Igeo values, the others except As (very severe enrichment) according to EF values were determined as severe enrichment, and according to PI, all three were determined as strong polluted. Pollution and element distribution maps were created with a geographical information system software. According to the results of correlation analysis and cluster analysis, the elements found to be contaminated are divided into two groups, whose locations and sources of contamination are different. The first group (Sn, Zn and Pb) is observed in the approximate centre of the study area and developed due to traffic emissions. The elements belonging to the second group (especially As, Mo and Sb) show high pollution values in the south-southeast of the study area. These pollutions are thought to be caused by the inadequate storage of mineral oils and batteries that are changed in the industrial site and from leaks in the oil production, storage, refining and transmission phase in TPAO, TuPRAS and BOTAS. The analysed samples were compared with the Soil Pollution Control Regulation and WHO standards, and Co, Ni and As element values were found to exceed the permissible values for health.