Risk Assessment and Chemical Fractionation of Heavy Metals by BCR Sequential Extraction in Soil of the Sapanca Lake Basin, Turkey

Sapanca Lake is an important drinking water source located by D-100 highway in the north and E-80 (TEM Anatolian Highway) and a railway line in the south. Heavy metal concentrations in roadside soils result from vehicle exhausts and the corroding metal parts of vehicles. Due to the difficulty of removing heavy metals from the soil, a significant pollution problem arises and this pollution also affects the water resources by means of rain. Although there are several industries, the highway located near the lake is the most important pollutant source for Sapanca Basin. Therefore, this study evaluated heavy metal concentrations, the chemical fractions of the metals and ecological risks (by using C-f, RAC and PERI) in the soil samples collected seasonally between 2015 and 2017 in Sapanca Lake Basin. Al and Fe were determined at very high amounts in all stations and the relationship between mean concentrations of other metals was determined to be Zn>Ba>As>Ni>Cr>Pb>Cu>Co>Cd. However, Zn, Ba, As, Ni, Cr, Pb, Cu, Co and Cd mean concentrations were determined as 87.63 mg/kg, Ba 86.87 mg/kg, 80.40 mg/kg, 58.62 mg/kg, 50.42 mg/kg, 41.90 mg/kg, 38.16 mg/kg, 13.98 mg/kg, 2.89 mg/kg respectively. Al, Fe, Co, Cr, Cu, Ni and Zn are mainly found in residual fractions in soil. According to the environmental risk assessment on the basis of soil stations, the 7th station has the highest GC(f) value, which means that the soil sample presents the highest environmental risk according to the contamination factors. On the other hand, Cd has serious potential ecological risk and As has considerable potential ecological risk in all stations.