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Ecotoxicological information

Toxicity to birds

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Description of key information

Four reliable acute toxicity studies showed that cloquintocet-mexyl to have no effect on mallard duck ot bobwhite quail at high exposure levels. Two  key studies performed according to OECD 206 (both GLP compliant with a reliability score of 1) reported NOEC values of at least 500 mg/kg in feed for both mallard duck and bobwhite quail.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for birds:
500 mg/kg food

Additional information

Cloquintocet-mexyl is of low toxicity to birds, as indicated by the results of the acute toxicity studies. Two GLP compliant guideline studies that are considered to be reliable without restriction reported LD50 values to mallard duck (Anas platyrhynchos) and bobwhite quail (Colinus virginianus) of 2000 mg/kg body weight (Hakin et al, 1989 and 1990, respectively).

In two further studies (both Hakin et al, 1990), cloquintocet-mexyl administered for 5 days in the diet showed to be non-toxic to birds since LC50values found in both mallard duck and bobwhite quail were > 5200 mg/kg feed.

In two reliable GLP studies performed according to OECD 206 (both Johnson, 1993), the dietary administration of up to 500 mg/kg feed over a 22 week period had no effect on adult mallard duck and bobwhite quail or their reproductive performance. Therefore, the NOEC was 500 mg cloquintocet-mexyl/kg feed.

No effects were detected on birds at high exposure levels in the laboratory so it is concluded that cloquintocet-mexyl under normal field use conditions will have no effect on birds. Accordingly, the key value used for this endpoint in the chemical safety report is the long-term NOEC of 500 mg/kg in food, which is the lowest concentration tested.