Polycyclic aromatic hydrocarbons in different layers of soil and groundwater-evaluation of levels of pollution and sources of contamination

Abstract

This study examined the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in soil and groundwater at a former cellulose factory in the city of Banja Luka, Republic of Srpska, Bosnia and Herzegovina. The objective of the study was to determine the concentrations of 16 PAHs in soil and groundwater at the site. The research area consisted of four representative locations in the industrial complex where the soil was sampled at depths of 0.3, 1, 2, 3, and 4 m and groundwater was sampled at 3.10, 2.50 and 3 m for two samples. In addition to the 16 PAHs, soil organic matter content and pH were also measured. The sum of the 16 PAHs (Σ16PAHs) in soil ranged from 0.99 to 2.24, 0.34 to 0.46, 0.24 to 0.32, 0.13 to 0.27 and 0.13 to 0.47 mg/kg for the 0.3, 1, 2, 3, and 4 m depths, respectively. Mean values were 1.70, 0.40, 0.28, 0.20 and 0.26 mg/kg, respectively. The Σ16PAHs in groundwater ranged from 0.23 to 4.50 mg/m3, with a mean value of 1.42 mg/m3. The concentrations of all 16 PAHs in the soil decreased with depth and there was no significant correlation between the concentrations of PAHs in the soil and groundwater. The concentrations of PAHs in the soil surface (0.3 m) and groundwater indicate that this industrial site is heavily contaminated and might need remedial action. Factor analysis indicates three sources of contamination, i.e. principal component (PC) PC1 (pyrogenic), PC2 (petrogenic) and PC3 (biomass), with 52.39%, 26.14% and 8.46% of the total variance, respectively. The results of this study reflect the effects of coal combustion (pyrogenic origin), petrogenic and biomass origin and may provide basic data for the remediation of PAHs in the location.