Chemical hazard and risk assessments often use physical-chemical properties to categorize and identify chemicals of concern. Most recently, legislation regarding the classification, labelling and packaging (CLP) has introduced new categories for chemical hazard assessment including persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM). Mobility is determined based on the logarithmic organic carbon–water partition ratio (log10 KOC) or logarithmic octanol–water partition ratio (log10 KOW) for neutral compounds and the logarithmic octanol–water distribution ratio (log10 DOW) for ionizable compounds, depending on the regulatory agency and the degree of mobility (Arp and Hale 2022). In this work we use all available KOC data in a consensus approach that takes into account the variability, uncertainty, different sources and types of data. Data sources include the OECD's eChemPortal, experimental datasets, and estimated values using poly-parameter linear free energy relationships (ppLFERs), OPERA, and EPI Suite. With Bayesian statistical inference approaches we aggregate values and their errors from these different sources to derive a probability distribution for the "true" log10 KOC value. For risk assessments, the classification of mobility can then be done using the mode of the distribution with uncertainties using 95 % credibility interval. For a more risk adverse approach, the 5 % quantile of each log10 KOC distribution can be compared to the mobility thresholds.

SB acknowledges support from Natural Sciences and Engineering Research Council of Canada via a Postdoctoral Fellowship.