Polychlorinated biphenyls in Nepalese surface soils: Spatial distribution, air-soil exchange, and soil-air partitioning.
The main objectives of the research were to estimate the relationship between the gas–particle partition coefficient, Kp, and the octanol–air partition coefficient, KOA, of polycyclic aromatic hydrocarbons, PAHs, and polychlorinated biphenyls, PCBs, at industrial and urban sites in the Vojvodina region, to compare the obtained slopes and intercepts of the log Kp vs. log KOA relations with the results of regression analyses reported in previous studies and to assess the consistency between the particle-bound fractions predicted by the KOA absorption model and the results obtained within field measurements. Fairly good log KP – log KOA correlations, with an average value of the correlation coefficients of 0.70, indicate that the partition coefficient KOA can be used as a prediction parameter of the gas–particle partitioning processes for both classes of compounds. The results of modelling the atmospheric distribution of PAHs using the KOA absorption model showed inconsistencies between the measured and predicted values of the particle-bound fraction, φ, of 1–2 orders of magnitude, while significantly higher discrepancies for PAHs in the Nap–Ace range were found. A similar variability of the measured/modelled φ values was obtained using the Junge–Pankow adsorption model, indicating the presence of particles enriched with PAHs. The conducted research showed that the KOA-based approach was less suitable for predicting the gas–particle partitioning of PCBs in urban and industrial sites, compared to the JungePankow model.