Heavy metal enrichments in Geyve (Sakarya): Soil and stream sediment geochemistry studies

The objective of this study is to evaluate the levels of heavy metal enrichment/ pollution, potential sources and origins of heavy metal enrichment from both geogenic and anthropogenic perspectives in soil and stream sediments. For this purpose, the heavy metal contents were determined for 719 soil samples from the Celaller site and 1317 soil samples from the Kamışlı site. Geochemical analyses were conducted on 133 stream sediment samples from drainage systems and 30 local rock samples. In addition, the geochemical analysis results of 651 drill core samples from S-1, S-2, and S-3 drillings at the Celaller site and 745 drill core samples from D-1, D-2, and D-3 drillings at the Kamışlı site were correlated with respect to lithological properties and geochemical data. To assess the pollution risk levels of heavy metals in the soil and stream sediment samples, the degree of contamination and pollution load index were calculated, and spatial distribution maps were created. The results revealed that the soils of the Celaller and Kamışlı sites exhibited contamination levels ranging from medium to high. In the pollution calculation for stream sediment, the presence of moderate-degree pollution samples was determined. Strong positive relationships were observed between arsenic and lead, as well as between cobalt and nickel, in the Celaller soil samples. In the Kamışlı soil samples, strong positive relationships were identified between cobalt and nickel, and positive relationships between copper and zinc. However, the correlations observed in the stream sediment samples were not clear. Hierarchical cluster analysis revealed the existence of statistically significant clusters of Co-Ni, Cu-Zn-V, and As-Pb in the Celaller site and Cu-Ni-V and Cu-Zn-Pb-As in the Kamışlı site. In the stream sediment samples, clusters of Co-Ni and Cu-Pb-V-As-Zn were identified. The results indicate that the enrichment of arsenic, copper, lead, vanadium, and zinc in soil samples is more closely associated with geogenic sources than anthropogenic sources. Additionally, the enrichment of cobalt and nickel is primarily related to serpentinite rocks.