Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

When the substance enters the environment, it is subject to various partitioning and abiotic and biological degradation processes. Relevant partitioning processes include adsorption to solids, such as soil and sediment, volatilization into air, and bioaccumulation within aquatic organisms. Degradation processes include hydrolysis in water and photo-oxidation in the atmosphere (abiotic processes) and biodegradation (biological process). 

 

Based on the vapour pressure, aqueous solubility, and molecular weight (184.28 g/mol), a Henry’s law constant is calculated. Using the Henry’s law constant and standard assumptions, EPISuite v4.10 modelling yielded volatilization half-lives from a model lake and river to be 5.5 days and 1.6 hours, respectively. This suggests that volatilization of the submitted material could be significant in certain natural water bodies. The measured adsorption coefficient of 1400 (log 3.15) suggests that the submitted material could sorb to natural suspended matter and sediment within natural water systems. Based on the estimated bioconcentration factor (BCF) of 21.3 L/kg (EPISuite v4.10), the bioaccumulation potential for the submitted substance is low.

 

The submitted material would be considered stable in water at environmentally relevant pH values of 4 to 7, as indicated by measured hydrolysis half-lives exceeding one year. However, as pH increases above 7, the submitted material becomes less stable in water, as indicated by a measured hydrolysis half-life of 15.5 hours at pH 9. Using the standard model within EPISuite, the atmospheric photo-oxidation half-life of the submitted material that volatilizes into air is 5.5 hours. Based on an OECD 301B test for ready biodegradability, the submitted material is considered “readily” biodegradable.

 

Fugacity modelling (Level III) was conducted for the components of the submitted material using EPI Suite (v.4.10). Input parameters for the submitted material included molecular weight 184.28 g/mol, melting point -22°C, water solubility 7.81 mg/L, log Kow 4.60, and Henry's law constant of 3.04 x 10-3 atm-m3/mol. Equal releases to air, water and soil were assumed. Media-specific half-lives were selected or calculated by the model. For atmospheric photo-oxidation, the model used a half-life in air of 5.5 hours. Biodegradation half-lives in water, soil and sediment were 360, 720, and 3240 hours, respectively. All other parameters used were the model default values. The results showed the distribution of the submitted material in the environment to be 2.29% to air, 29.7% to water, 67.6% to soil and 0.476% to sediment. 

 

The submitted material cannot be considered a persistent, bioaccumulative, and toxic material by any international assessment of PBT properties. The submitted material is readily biodegradable and has low bioaccumulation potential (estimated BCF of 21.3 L/kg), therefore it is neither persistent “P” nor bioaccumulative “B”. While the substance may meet some international criteria for aquatic toxicity, it must exceed the criteria for all three parameters (i.e., it must be P plus B plus T). Thus, the submitted material is not a PBT.