The Fragment Constant Method for Predicting Octanol–Air Partition Coefficients of Persistent Organic Pollutants at Different Temperatures

Abstract

The octanol-air partition coefficient ͑K OA ͒ is a key physicochemical parameter for describing the partition of organic pollutants between air and environmental organic phases. Experimental determination of K OA is costly and time consuming, and sometimes restricted by lack of sufficiently pure chemicals. There is a need to develop a simple but accurate method to estimate K OA. In the present study, a fragment constant model based on five fragment constants and one structural correction factor, was developed for predicting log K OA at temperatures ranging from 10 to 40°C. The model was validated as successful by statistical analysis and external experimental log K OA data. Compared to other quantitative structure-property relationship methods, the present model has the advantage that it is much easier to implement. As aromatic compounds that contain C, H, O, Cl, and Br atoms, were included in the training set used to develop the model, the current fragment model applies to a wide range of chlorinated and brominated aromatic pollutants, such as chlorobenzenes, polychlorinated naphthalenes, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers, all of which are typical persistent organic pollutants. Further study is necessary to expand the utility of the method to all halogenated aliphatic and aromatic compounds.

Occurrence and gas/particle partitioning of PAHs in the atmosphere from the North Pacific to the Arctic Ocean

“…5. The values of logK OA for PAHs at different temperatures were calculated with the fragment constant method developed by Li et al (2006). Clearly, the predicted 4 values of PAHs by the soot-air model were obviously closer to the field measured values compared with the values predicted by the JeP model and the K OA -based model.…”

Physiochemical Properties and Environmental Levels of Legacy and Novel Brominated Flame Retardants

“…As with V p , log K OA depends on the temperature. Higher log K OA values imply stronger binding to the organic content of particles [13,14].…”

Estimating population exposure to ambient polycyclic aromatic hydrocarbon in the United States – Part I: Model development and evaluation

“…The values of A oa and B oa for 14 of the 16 PAH species (except for NAPH and pyrene (PYR)) follow the recommendations of Odabasi et al (2006). For NAPH and PYR, K oa values under different temperatures are obtained from a fragment constant method described by Li et al (2006) to determine the A oa and B oa values using linear regression. A list of A oa , B oa and log K oa values for the 16 PAH species is shown in Table 1.…”