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Environmental fate & pathways

Phototransformation in water

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Description of key information

Studies of photolysis in water are not necessary for terephthalic acid.  

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Additional information

Studies of phototransformation in water are not required for terephthalic acid.

Under environmental conditions, photolysis is unlikely to make a significant contribution to the dissipation of terephthalic acid (or its salts), 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 terephthalic acid on the growth of the unicellular aquatic alga Pseudokirchneriella subcapitata (Government of Japan, 2003d): the initial measured exposure concentration of 19.0 mg TPA/L remained unchanged over the course of the static, 72 -hour incubation at pH 7.8 +/- 0.3 and under continuous illumination at 4100 to 4300 lux. These data (DT50 > 3 days) suggest that TPA is not prone to rapid photolysis in the aquatic environment. Ready biodegradability test data, on the other hand, show > 60% mineralisation (CO2 production) within 5 days when TPA was dosed at 10 and 20 mg/L (Lebertz, 1991a).