Evaluation of Physicochemical Property Data in the ECHA Database

The database of the European Chemicals Agency (ECHA) is one of the most important databases that contains physicochemical properties, also because these data are used for the regulation of chemicals in the European Economic Area. The present study investigates the availability and quality of the data in the ECHA database for the logarithmic octanol-water partition coefficient (log(10) K-OW), solubility in water (S-W), vapor pressure (p(V)), air-water partition coefficient, boiling point (T-b), second-order rate constant for the degradation with OH radicals, and the soil adsorption coefficient. For the evaluation of the data, calculations were run with COSMOtherm for the majority of the mono-constituent, neutral organic substances that are fully registered under the EU Regulation on the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH). The COSMOtherm data were evaluated against data from the PHYSPROP database, a manually curated database of experimental property data, to ensure that the COSMOtherm data were free of systematic errors. The comparison between COSMOtherm and the experimental data in the ECHA database showed that the data agree (within some variability) for many of the endpoints. However, there are also certain ranges with substantial discrepancies. These include log(10) K-OW > 8, S-W < 10(-3) mg/l, p(V) < 10(-6) Pa, and T-b > 400 degrees C. The deviations between the non-experimental data and the COSMOtherm values are for all endpoints on average higher than the deviations between the experimental data and the COSMOtherm values. With this study, we provide COSMOtherm data for more than 4400 substances that can be used in the future for the hazard and risk assessment of these chemicals.