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Environmental fate & pathways

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When released into water, ETU (Imidazolidine-2-thione) was found to be extremely stable to hydrolysis over the pH range 5-9 at 90°C for a 3 month period (Cruickshank PA, 1973). Indeed, hydrolysis is not expected to occur due to the lack of hydrolysable functional groups. Volatilization from water surfaces is not expected based upon a Henry's Law constant of 0,04 Pa.m3/mol. Using this Henry's Law constant and an estimation method (Lyman WJ et al; 1990), volatilization half-lives for a model river and model lake are 62 days and 676 days, respectively. Last, ETU has a low potential to bioaccumulate in aquatic species based on a measured log Kow of –0.67.

When released into terrestrial environments, volatilization of ETU from moist soil surfaces is not expected to be an important fate process given a Henry's Law constant of 0,04 Pa.m3/mol . It is not readily biodegradable under aerobic conditions (0 % of biodegradation after 28 days) and is not expected to sorb significantly to soil and sediment (based upon its log Kow value).

ETU is not PBT/vPvB and the chemical safety assessment indicates no unacceptable risk for any environmental compartment (soil, sediment, water) when considering ETU as not biodegradable as a worst-case scenario. Therefore, no further testing is required on ETU biodegradation in any environmental compartment.