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Environmental fate & pathways

Phototransformation in soil

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Description of key information

A study of photodegradation in soil was conducted, according to EPA guideline. This study reported a DT50 of 9.7 hours on silty loam soil, under laboratory conditions. The equivalent value for use in the chemical safety assessment is the DT50 under summer sunlight conditions of 2.1 days (latitude 30°N).

Key value for chemical safety assessment

Half-life in soil:
2.1 d

Additional information

Photodegradation of cloquintocet-mexyl in soil was investigated in a GLP compliant study. This study was conducted to EPA guideline Subdivision N 161-3 and was considered to be reliable without restriction (1). The photolysis on soil surface of a silty loam was studied by irradiation with a Xenon arc lamp simulating Florida summer sunlight (latitude 30°N). On dry soil no degradation was observed whereas a half-life of cloquintocet-mexyl was determined to be 9.7 hours in viable soil. The equivalent DT50 was 2.1 days for degradation under summer sunlight conditions. Under the test conditions used the dissipation of CGA 185072 was primarily by microbial degradation. In viable soils the main degradation products were CGA153433 and carbon dioxide.