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Environmental fate & pathways

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The biodegradability of the target substance, 1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol (CAS 91648-65-6) was investigated according to OECD Guideline 301C (Katsuura, 1990). Furthermore, the read-across substances 1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-dodecanethiol (No CAS, no EC) (Müller, 1999 and Rheinchemie) and 5-(dodecyldithio)-1,3,4-thiadiazole-2(3H)-thione (CAS 50530-43-3) (Takagi, 1984) were tested in accordance to reliable guidelines and study methods. All substances were found to be "not readily biodegradable".

During the life cycle of the target substance, no exposure to water, sediment and soil is intended. Also indirect exposure to the environment is unlikely since adequate controls ensure that it would not be released neither to the aquatic nor the terrestrial compartment. In accordance to ECHA Guidance documents (Chapter R.7b and Chapter R.7c) no further investigations are triggered if the PEC/PNEC ratio is below 1. Further degradation studies in water, sediment and soil can be therefore waived based on exposure conditions and the low risk demonstrated by the RCRs (less than 1) in accordance to REACH, Annex IX, Section 9.2.1.2, column 2 (water), REACH, Annex IX, Section 9.2.1.4 (sediment) and REACH, Annex IX, Section 9.2.1.3, column 2 (soil), respectively.