Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Bidegradation: The submission substance is not readily biodegradable, i.e. observed biodegradation was 2% after 28 days.

Hydrolysis: The submission substance is hydrolytically stable.

Bioaccumulation: The submission substance is not bioaccumulative - BCF of 269 L/kg wet weight derived as a conservative estimate from a reliable QSAR ( US EPA T.E.S.T. v. 4.2.1 BCF Consensus Method supported by two further models) will be used for chemical safety assessment.

Adsorption / desorption: Koc's of the submission substance were: 887 ± 176, 1197 ± 105, and 659 ± 3 (mL/g) for three different types of soil (tested range of soil organic matter content: 0.4 % - 7.8 %; clay content: 3 % - 30 %). Koc used as key value: 1197 (mL/g) / log Koc of 3.1.

Additional information

Biodegradation

A reliable test on ready biodegradation of the submission substance is available, conducted according to OECD 301D (Closed Bottle Test) and in compliance with GLP (RL1, 2003). After 28 days, the amount of biodegradation was 2%. The submission substance is expected to persist in the environment.

 

Hydrolysis

A reliable key study was conducted according to OECD TG 111 (hydrolysis screening test) and in compliance with GLP. Observed decrease of the test item was related to adsorption to the vial glass but not to abiotic degradation of the submission substance. Hence, the submission substance was considered hydrolytically stable (half-life > 1 year at 25 °C). No hydrolytical degradation of the submission substance is expected to occur in the environment.

 

Bioaccumulation

A relevant bioaccumulation potential could be safely ruled out by a valid and reliable QSAR study (RL1) comprising QMRF and QPRF for the key model, as well as two valid supporting models differing in methodology and corroborating results of the key model. The results of the key model (BCF 141 L/kg wet weight; US EPA T.E.S.T. v. 4.2.1 BCF Consensus Method) and the supporting models (BCF= 222 L/kg and 474 L/kg wet weight based on corrected and non-corrected metabolic rate constant, respectively according to Arnot and Gobas (2003) Bioconcentration Model; BCF= 610 L/kg wet weight according to equation by Veith et al. (1979)) conclusively demonstrate that the submission substance is definitely not bioaccumulative (BCF clearly below 2000 L/kg); and that the worst-case BCF of 269 L/kg wet weight based on key model T.E.S.T. Consensus Method results and manual consideration of the maximum underestimation from 14 similar compounds will be sufficiently conservative to be used as the relevant figure for chemical risk assessment.

 

Adsorption / desorption

A reliable key study was performed according to OECD 106 (adopted 1981) and in compliance with GLP. Three different types of soil were used to investigate the adsorption / desorption potential, representing a range of soil organic matter content (0.4 % - 7.8 %) and clay content (3 % - 30 %). Results show that the extents of adsorption were directly related to soil organic matter contents. The derived Koc values indicate a potential of the submission substance to adsorb to soil and sediment.