Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The adsorption coefficient of alpha-methylstyrene was investigated in a study conducted according to OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)) and EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC)). The soil adsorption coefficient log Koc was determined to be 2.8 (Koc=692). The calculation (EPIWIN v3.11, PCKOC v1.66) of the soil sorption coefficient Koc of alpha-methylstyrene yielded a Koc=817 (log Koc=2.9). Based on the results and taking into account the classification scheme of Blume and Ahlsdorf (1993), alpha-methylstyrene can be regarded as a substance with high sorption potential onto soil organic matter. Alpha-methylstyrene is highly volatile from aqueous solution (Henry's Law constant calculated using EPIWIN v3.11, HENRYWIN v3.10: 438.63 Pa x m³/mole and calculation according to the equation H=vp/ws: 282 Pa x m³/mole at 25°C each). The Henry's Law constant calculated according to the equation H=vapor pressure/water solubility and using reliable experimental derived values indicates that alpha-methylstyrene is highly volatile from aqueous solution (H=258.32 Pa x m³/mole at 25°C). The environmental distribution of alpha-methylstyrene was calculated using the fugacity model Mackay Level I v3.00. The main target compartment of the distribution was calculated to be air (98.4%).