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Environmental fate & pathways

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Hydrolysis of the substance is not expected, based on the absence of hydrolysable functional groups.

The stability of the substance in different aqueous test solutions towards photolysis was investigated. The experiments were carried out at two concentrations in deionised water and in an algae nutrient medium. Conditions for radiation, ventilation and nutrient medium corresponding those conditions used in ecotox testing in accordance with Commission Regulation (EC) No 761/2009 amending Regulation No 440/2008, Method C.3 ‘Freshwater Alga and Cyanobacteria, Growth inhibition test’ (2009) which is equivalent to OECD Guideline for Testing of Chemicals No. 201 (2006) ‘Alga, Growth Inhibition Test’. Under the same conditions, but in the dark, test solutions at the same concentrations were performed to serve as controls. Degradation was followed via HPLC analysis.

In deionised water the half-life times were 9.2 days at 10 mg/L and 9.6 days at 32 mg/L, and in OECD nutrient medium a half-life time of 3.2 days at 10 mg/L and 7.7 days at 32 mg/L was obtained. The longer half-life time obtained in the tests at the concentration of 32 mg/l in the presence of light may be due to hindered radiation of the molecules of the substance, as the solution was dark coloured. The results of the test series conducted in the dark show stability of the test substance under exposure conditions. It is clearly demonstrated, that the susbtance is rapidly degradable by photolysis. As no additional peaks are shown in the chromatograms transformation products were not detected via HPLC. Due to the complex nature of photochemical processes with a large number of possible transformation pathways, and sub-sequent reactions of produced intermediate species, confirms the difficulty on identification of transformation products.