The use of magnetic susceptibility and chemical analysis data for characterizing heavy metal contamination of topsoil in Denizli city, Turkey

Abstract

Denizli is one of the most rapidly growing cities in Turkey having experienced fast urban and industrial development in the last decades, engendering a serious threat to the environment and the population health. Therefore, this study used the magnetic susceptibility method to evaluate the contamination degree of most parts of Denizli city. X-ray fluorescence (XRF) analysis was performed on samples chosen from different parts of the study area to identify the quantity and origins of the heavy metals present in the study area corresponding to the magnetic susceptibility measurements. Multivariate statistical analysis such as Cluster analysis (CA) and the principal component analysis (PCA) was performed for the best understanding of the relationship between heavy metal contamination, magnetic susceptibility measurements and XRF analysis results. The environmental status of the study area was evaluated by the aid of elaboration and interpretation of the contamination factor (CF), geoaccumulation index (Igeo), Enrichment factor (EF) and the pollution load index (PLI) which allowed the comparison between the different polluted parts of the study area. The results obtained as maximum values from the calculation of the contamination factor were found as follows: Fe (30.98), Cr (25.86), Ni (14.71), Zn (9.24), Cu (7.96), Pb (5.86). The mean values obtained for the implemented geoaccumulation index were found for each element as follow; Fe (4.39), Cr (4.12), Ni (3.29), Cu (2.44), Pb (2.01) Zn (2.62) while the enrichment factor's results were found as follow Fe (11.80), Cr (11.07), Ni (5.90), Cu (3.87), Pb (2.71) Zn (4). The average value of the pollution load index reflects the heavy pollution of the study area by reaching a value of 7.7. The contour maps plotted for the distribution of heavy metals concentration and magnetic susceptibility measurement showed similar pollution degrees in the city industrial zone and near the main highway (Antalya Highway), which passes through the city. This high heavy metal load gradually decreases toward the city borders. Furthermore, the content of heavy metal and the PLI are notably positively correlated with the magnetic susceptibility measurements. Overall, results testify to the effectiveness of the magnetic susceptibility method for applications in determining environmental contamination caused by heavy metals.