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Environmental fate & pathways

Phototransformation in water

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Description of key information

According to REACH requirements, studies of photolysis in water are not necessary for dimethyl terephthalate.  

Key value for chemical safety assessment

Additional information

Studies of phototransformation in water are not required for dimethyl terephthalate.

Under environmental conditions, photolysis is unlikely to make a significant contribution to the dissipation of dimethyl terephthalate, compared to the rate of its removal by biodegradation.

Support for this view is provided by the analytical data from a study of the effect of dimethyl terephthalate on the growth of the unicellular aquatic alga

Desmodesmus subspicatus (BASF

, 2010a): the initial measured exposure concentration of 29.4 mg DMT/L was reduced by 10% over the course of the static, 72 -hour incubation at pH 8.1 and under continuous illumination at 5247 lux. These data (DT50 > 3 days) provide evidence that DMT is not prone to rapid photolysis in the aquatic environment. Ready biodegradability test data, on the other hand, show > 60% mineralisation (CO2 production) within 14 days when DMT was dosed at ca. 10 and 100 mg/L (Schoeberl, 1993a, CITI, 1980).