Evaluation of PCDD/F levels in ambient air and soils and estimation of deposition rates in Kocaeli, Turkey

PCDD/F analyses were made in soil and ambient air samples taken from Kocaeli, an industrialized area of Turkey. Results showed that the levels of PCDD/F pollution are comparable to the levels observed in the various urban areas in the world. PCDD/F concentrations in surface soils ranged between 0.4 and 4.27 pg I-TEQ kg−1 with a geometric mean of 0.76 pg I-TEQ kg−1, while those in ambient air were between 23 and 563 fg m−3, with geometric mean of 82.0 fg m−3. Ambient air PCDD/F concentration in the city center was about 10 times higher than those in the rural area. Combustion activities present in the area were assessed to be the most significant source of the PCDD/F pollution based on the congener and homologue profiles and statistical analysis of the data. The deposition rate modeling of USEPA was applied and the deposition rates were determined in the range between 7.6 and 66.3 ng I-TEQ m−2 year−1 with a geometric mean of 15.9 ng I-TEQ m−2 year−1. The rates were higher than the recommended deposition rates in relation to the tolerable daily intake (TDI) range of PCDD/Fs for humans. The deposition velocities computed were also found to be high in both low and highly chlorinated PCDD/Fs, and this was attributed to the vapor phase deposition of volatile PCDD/Fs, and the scavenging effect of the precipitation on the particle-bound PCDD/Fs.