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Environmental fate & pathways

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A reliable measured biodegradation study for HQEE is available and included in the dossier.

 

Boeri and Ward (2003) conducted a reliable (Klimisch 1) GLP compliant study according to OECD 301 B (CO2 evolution) methods. The biodegradability of HQEE exposed to microorganisms derived from unacclimated activated sludge obtained from a municipal wastewater treatment plant was investigated under aerobic static exposure conditions. After 28 days the test substance showed 9% degradation, based on measured CO2. The study concluded that HQEE can not be considered to be readily biodegradable.

 

Lawrence and Ruffing (1995) conducted a reliable (Klimisch 1) GLP compliant study according to OECD 302 B methods. The inherent biodegradability of HQEE exposed to microorganisms derived from microoganisms from mixed liquor of suspended solids (sludge) obtained from a municipal wastewater treatment plant was investigated under aerobic static exposure conditions. DOC concentrations were measured on days 0, 1, 4, 6, 8, 11, 15, 18, 22, 25, 27, and 28 for loss. During the test, the positive control yielded DOC removals of >70% within 14 days, fulfilling test validity requirements. Biodegradation, based on DOC removal, averaged 97% after 28 days. The study report concludes the substance is inherently biodegradable.

 

Waiver. In accordance with Column 2 of REACH Annex IX, the simulation test on ultimate degradation in surface water, the soil simulation test and the sediment simulation test (required in Sections 9.2.1.2, 9.2.1.3 and 9.2.1.4 respectively) do not need to be conducted as direct or indirect exposure of surface water, soil and sediment is negligible. Exposure potential is expected to be negligible since the substance is only used as a monomer to make polyurethane mouldings. There is negligible exposure to aqueous process streams during downstream use and hence also negligible emission to a sewage treatment plant. Exposure of soil and sediment is hence also considered negligible. The chemical safety assessment does not indicate any need to investigate further the degradation of the substance and its degradation products. Also, the substance’s low hydrophilicity is demonstrated by the very low log octanol-water partition coefficient (Log Kow) of 0.41 at a neutral pH indicating low adsorptive potential. Therefore, no additional degradation testing is necessary based on negligible exposure. Identification of degradation products (required in Section 9.2.3) is also not necessary.