Atmospheric concentrations, distributions and air-soil exchange tendencies of PAHs and PCBs in a heavily industrialized area in Kocaeli, Turkey Banu Cetin a, * , Sema Yurdakul b , Melek Keles c , Isil Celik a , Fatma Ozturk c , Cevdet Dogan a a Environmental Engineering Department, Gebze Technical University (GTU), 41400, Gebze, Kocaeli, Turkey b Environmental Engineering Department, Suleyman Demirel University, 32260, Isparta, Turkey c Environmental Engineering Department, Abant Izzet Baysal University (AIBU), 14030, Bolu, Turkey highlights  Air and soil concentrations of PAHs and PCBs were investigated in industrialized region in Turkey.  The highest PAH concentrations were obtained in winter indicating the impact of combustion sources.  The PCB concentrations indicated the important continuing sources such as iron-steel plants.  The PAHs were higher in urban while the PCBs were higher in industrial/urban soils.  Fugacity ratio results showed that soil acted as a secondary source for PAHs in industrial-urban sites. article info Article history: Received 9 March 2017 Received in revised form 16 May 2017 Accepted 17 May 2017 Available online 19 May 2017 Handling Editor: R. Ebinghaus Keywords: PAHs PCBs Air-soil exchange Passive sampling abstract Dilovasi is one of the heavily industrialized areas in Turkey with serious environmental problems. In this study, the atmospheric concentration of PAHs and PCBs were measured for a whole year at 23 sites. The average ambient air S 15 PAH and S 41 PCB concentrations were found as 285 ± 431 ng m 3 and 4152 ± 6072 pg m 3 , respectively. PAH concentrations increased with decreasing temperature especially in urban areas, indicating the impact of residential heating. However, PCB concentrations mostly increased with temperature probably due to enhanced volatilization from their sources. The gradient obtained for PCBs, rural < suburban < urban < industrial/urban, is more clear than those obtained for PAHs. The average S 15 PAH and S 41 PCB soil concentrations were found as 992 ± 1323 and 18.8 ± 32.0 mg kg 1 , respectively. PCB soil concentrations did not show significant temporal variations while PAH concentrations were variable especially for urban areas. The volatilization tendencies of low and medium molecular weight PAHs from soil to air were higher in industrial-urban areas than rural sites, showing that soil was a secondary source for PAHs. Fugacity ratios of PCBs were mostly <1.0 for the whole sampling period. Although the source/sink tendency of soil for some PCBs depends on their volatility, considering the whole data, PCBs were generally deposited to soil. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Turkey has three industrialized regions that cause serious environmental problems. Dilovasi, a highly industrialized area, is one of these regions and located at the northwest part of Turkey by the Marmara Sea shoreline. In Dilovasi, the industrial sites are within the residential areas and the distinct is under heavy traffic. Consequently, cancer has become the main reason of deaths in the area (Arslan et al., 2013). Numerous companies working in different sectors such as iron and steel industry, glass, paint, wood and chemical industries are located in Dilovasi adjacent to two motor- ways, railway lines and many seaports. Therefore, the problem of air pollution threatens the public health in the Dilovasi region. Recent studies conducted in the ambient air of Dilovasi have mostly focused on the air quality data including the concentrations of PM, SO 2 , NO x and O 3 (Dogruparmak and Ozbay, 2011; Pekey and Ozaslan, 2013). However, persistent organic pollutants (POPs) * Corresponding author. E-mail address: bcetin@gtu.edu.tr (B. Cetin). Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere http://dx.doi.org/10.1016/j.chemosphere.2017.05.103 0045-6535/© 2017 Elsevier Ltd. All rights reserved. Chemosphere 183 (2017) 69e79