Investigation of PAHs, PCBs and PCNs in soils around a Heavily Industrialized Area in Kocaeli, Turkey: Concentrations, distributions, sources and toxicological effects

Soil is an important environmental medium reflecting the level and the spatial distribution of air pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs). Soil concentrations of PCNs measured in the present study were generally higher and PCBs concentrations were considerably higher than those reported in the literature, while PAHs concentrations were comparable. Combustion related PCNs congener ratios to their total concentrations and PAHs diagnostic ratios suggested the substantial contribution of combustion sources and the statistically significant correlation between PCBs and PCNs (r=0.88) indicated that these POPs were emitted from the common sources. Principal Component Analysis was also performed to further assess the possible sources of individual POPs. The results showed the contribution of traffic, petroleum and coal/biomass combustion and iron-steel production. Toxicological effects of POPs in soil were investigated. BaP was used as the marker of carcinogenic PAHs. Seven carcinogenic PAHs concentrations (Σ7cPAH) including BaA, CHR, BbF, BkF, BaP, IcdP and DahA were also used as a parameter to evaluate carcinogenic potency of PAHs. As PCBs and PCNs show dioxin-like toxicities, their toxicological implication were estimated using TCDD equivalence. The results show that the study area faced with severe environmental problems even though the data sets without the complete set of dioxin like PCBs and PCNs would show only a part of the whole toxicological picture.