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Ecotoxicological information

Toxicity to birds

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Description of key information

The NOAEL for Mallard ducks and Northern bobwhite quails amounted to 5620 ppm (approx 2500 - 1500 mg/kg bw/d, based on food consumption per day and body weight on day 0 and 5).
NOEC for the chronic study with Bobwhite quail is 300 ppm (equal to 300 mg/kg food and 31.6 mg/kg bw/d).

Key value for chemical safety assessment

Short-term EC50 or LC50 for birds:
2 510 mg/kg food
Long-term EC10, LC10 or NOEC for birds:
300 mg/kg food

Additional information

Two acute studies with Mallard ducks and one with Northern bobwhite quails were found to be valid. Fink, et al. (1990) exposed ducks to a range of concentrations of sodium chlorate by once intubating a solution in distilled water into the crop. The birds were observed for 14 days and no mortality or body weight changes occurred during this period (No Observed Adverse Effect Level (NOAEL) > 2510 mg/kg). Long, et al. (1991) fed 10 day old ducks chicks and Northern bobwhite chicks for a period of 5 days with a range of concentrations of sodium chlorate mixed into the diet with corn oil. The ducks were observed for this period and up till three days after exposure. No mortality or clinical signs of toxicity were observed throughout the test. Body weight and food consumption were not affected. Sodium chlorate is not toxic at the highest concentrations tested. The NOAEL in both studies amounted to 5620 ppm (approx 2500 - 1500 mg/kg bw/d, based on food consumption per day and body weight on day 0 and 5).

One chronic study was found with Colinus virginianus (Bobwhite quail) and was considered valid. Twenty pairs (1 male and 1 female) of 6 months old bobwhite quails per treatment and 20 pairs for the control were selected. First they were pre- treated for 2 weeks, where they received untreated food. Then a period of 10 weeks pre-egg production started in which they were exposed to different concentrations of sodium chlorate. And after this a 12 weeks period of egg production started. The resulting chicks were reared for 14 days. The number of eggs laid was significantly lower at 1000 ppm. The number of eggs laid per female decreased at 1000 ppm and the number of damaged eggs laid was lower at 100 ppm. The percentage of damaged eggs in the control was greater than the suggested range in the guideline. All other parameters were acceptable and it is possible that the difference is due to the strain of birds used. Egg shell thickness increased at 1000 ppm. The percentage of normal hatchlings of viable embryos was significantly reduced at 1000 rpm. The percentage of 14–day survivors of eggs laid per replicate was significantly reduced at 1000 ppm. Body weight on hatching was significantly reduced at 1000 ppm. The percentage of viable embryos was significantly reduced at 1000 ppm. Additionally the percentage of live 3–weeks embryos of viable embryos was significantly reduced at 300 and 1000 ppm. The results of the hatching data would suggest that the difference at 300 ppm is not biologically significant. This endpoint is not required by OECD Guideline 206 and moreover, it is not a true endpoint but an intermediate measurement between egg viability and hatching, therefore this result is not taken into account for determination of the NOEC. Effect data: NOEC = 300 ppm (equal to 300 mg/kg food and 31.6 mg/kg bw/d).