2-Pyridinecarboxylic acid, 4-amino-3,6-dichloro-

Toxicity to birds

Description of key information

NOEC (toxicity, reprotoxicity) = 2700 mg a.i./kg diet (Mallard duck) male/female, OECD 206, EPA OPP 71-4, Mach (2003)
NOEC (toxicity, reprotoxicity) = 2700 mg a.i./kg diet (Northern bobwhite) male/female, OECD 206, EPA OPP 71-4, Mach (2003)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for birds:

2 700 mg/kg food

Additional information

Several toxicity studies on birds are available. The acute screening study and the acute oral studies were included as supporting information and the two reproductive toxicity studies are included as key studies. All of the studies, bar the screening study, were conducted under GLP conditions and in accordance with standardised guidelines and were assigned a reliability score of 1 in line with the criteria of Klimisch (1997). The screening study was assigned a reliability score of 2. Each of the available studies is summarised below, in turn.

In the acute screening study, reported by Troup (2001) the acute toxicity of the test material to the Northern Bobwhite was investigated in a study which was conducted in accordance with the standardised guideline EPA OPP 71-1. The study was not performed to GLP standard.

During the study groups of 6 Northern bobwhites received a single gavage administration of test material, as a suspension in corn oil, at concentrations of 0, 292, 486, 810, 1350 or 2250 mg/kg bw. Observations were performed twice daily during the 7-day definitive test. Inspections were made to monitor mortality and moribundity of the test birds and to observe clinical symptoms indicative of test material effects. Body weights of the test birds were measured on the day of dosing (day 0).

No test material related mortality or moribundity were observed in any of the test birds. Test material related signs of intoxication were observed in the groups dosed 486 to 2250 mg/kg bw. The signs ranged from mild hyper-excitability in the 486 mg/kg bw group up to severe hyper-excitability, ataxia and an unkempt appearance in the 1350 and 2250 mg/kg bw groups.

Therefore, under the conditions of the study the LD50 was determined to be in excess of 2250 mg/kg bw, the highest dose tested.

In the study reported by Gallagher (2003) the acute toxicity of the test material to the Northern Bobwhite was investigated in a study which was conducted under GLP conditions and in accordance with the standardised guideline EPA OPP 71-1.

During the study groups of 5 male and 5 female birds received a single gavage administration of test material, as a suspension in distilled water, at concentrations of 0 (vehicle control), 8, 14, 23, 38, 63 and 292 mg a.i./kg bw. The birds were fasted for approximately 17 hours prior to dosing. Observations were performed at least once daily. Body weights were measured individually at the initiation of the test and on days 3, 7 and 14. Feed consumption was determined by measuring the change in the weight of the feed presented to the birds over a given period of time.

None of the birds died during the study. When compared to the control group, there were no treatment related effects on body weight in the 8, 14, 23, 38, 63 or 292 mg a.i./kg dosage groups at any of the body weight intervals. In addition, there were no effects on feed consumption at any of the dosages tested. A number of clinical signs were noted throughout the test.

Therefore, under the conditions of the study, the LD50 was determined to be in excess of 292 mg a.i./kg bw. Based upon slight signs of toxicity noted at the 23 mg a.i./kg dosage level, the no-observed-effect-level (NOEL) for Northern Bobwhite exposed to test material as a single oral dose was 14 mg a.i./kg.

In the study reported by Gallagher et al. (2001) the acute toxicity of the test material to the Northern Bobwhite was investigated in a study which was conducted under GLP conditions and in accordance with the standardised guideline EPA OPP 71-1.

During the study groups of 5 male and 5 female birds received a single gavage administration of test material, as a suspension in distilled water, at concentrations of 0 (vehicle control), 63, 292, 486, 810, 1350 and 2250 mg a.i./kg bw. The birds were fasted for approximately 16 hours prior to dosing. Observations were performed at least once daily. Body weights were measured individually at the initiation of the test and on days 3, 7 and 14. Feed consumption was determined by measuring the change in the weight of the feed presented to the birds over a given period of time.

None of the birds died during the study. When compared to the control group, there was a treatment related reduction in body weight gain or a body weight loss among males and females at the 1350 and 2250 mg a.i./kg dosage levels from Day 0 to Day 3. In addition, there appeared to be a corresponding reduction in feed consumption among males and females in the 2250 mg a.i./kg treatment group for this same period. All birds were subjected to gross necropsy following test termination. One male in the control group was noted with a friable liver and distended gizzard. In addition this bird was noted with a malformed foot. Areas of hyperaemia in the small intestines were observed in three control birds, and in one bird each in the 63, 292, 810 and 1350 mg a.i./kg treatment groups. A male at the 292 mg a.i./kg dosage was noted with a small cyst attached to the left testis. None of the above findings were considered to be treatment related. The necropsy results for all other birds were not remarkable.

Therefore, under the conditions of the study, the acute oral LD50 value for Northern Bobwhite exposed to test material as a single oral dose was determined to be greater than 2250 mg a.i/kg, the highest dosage tested.

In the study reported by Gallagher et al. (2001) the toxicity of the test material to the Northern Bobwhite was assessed in a study which was conducted under GLP conditions and in accordance with the standardised guidelines EPA OPP 71-2 and OECD 205.

During the study groups of 10 birds were fed diets containing nominal concentrations of test material of 0 (plain diet control), 178, 316, 562, 1000, 1780, 3160 and 5620 ppm a.i. for a period of 5 consecutive days. Following the five-day exposure period all groups were given untreated basal diet for three days. During the study the birds were observed for mortality and clinical signs; body weights and feed consumption were also recorded.

None of the birds died during the study and no clinical signs of toxicity were noted at any of the concentrations tested; all treatment birds were normal in appearance and behaviour throughout the test. When compared to the control group, there were no apparent treatment related effects on body weight among birds in any of the treatment groups at any body weight interval. In addition, there were no apparent treatment related effects on feed consumption at any of the concentrations tested.

Therefore, under the conditions of the study, the dietary LC50 value for Northern Bobwhite exposed to the test material was determined to be greater than 5620 ppm a.i., the highest concentration tested. The no mortality concentration and the no-observed-effect concentration for northern bobwhites exposed to test material in the diet were 5620 ppm a.i.

In the study reported by Gallagher et al. (2001) the toxicity of the test material to Mallard ducks was assessed in a study which was conducted under GLP conditions and in accordance with the standardised guidelines EPA OPP 71-2 and OECD 205.

During the study groups of 10 birds were fed diets containing nominal concentrations of test material of 0 (plain diet control), 178, 316, 562, 1000, 1780, 3160 and 5620 ppm a.i. for a period of 5 consecutive days. Following the five-day exposure period all groups were given untreated basal diet for three days. During the study the birds were observed for mortality and clinical signs; body weights and feed consumption were also recorded.

None of the birds died during the study and no clinical signs of toxicity were noted at any of the concentrations tested; all treatment birds were normal in appearance and behaviour throughout the test. When compared to the control group, there were no apparent treatment related effects on body weight among birds in any of the treatment groups at any body weight interval. In addition, there were no apparent treatment related effects on feed consumption at any of the concentrations tested.

Therefore, under the conditions of the study, the dietary LC50 value for mallard ducks exposed to the test material was determined to be greater than 5620 ppm a.i., the highest concentration tested. The no mortality concentration and the no-observed- effect concentration for mallards exposed to test material in the diet were 5620 ppm a.i.

In the study reported by Mach (2003) the effect of the test material on the reproductive performance of Mallards was investigated in a study which was conducted under GLP conditions and in accordance with the standardised guidelines OECD 206 and EPA OPP 71-4.

During the study birds were paired (1 male, 1 female); 13 pairs of birds were fed test diets containing test material at concentrations of 0 (plain diet control), 675, 1350 or 2700 mg a.i./kg diet. Diet was presented daily to the birds for 20 consecutive weeks. During the study, the adult birds were observed daily for test-material related effects. Body weights were measured on day 0 and at the end of weeks 2, 4, 6, 8 and 20 (study termination). Feed consumption of each pair was determined weekly. Reproductive parameters included determination of the number of eggs laid per hen and eggshell thickness. Defective and cracked eggs were also recorded. On approximately day 14 of incubation, eggs were candled to determine the viability of the embryos. All embryos considered viable were kept in the incubator for further development. All viable embryos were examined for development at approximately day 21 of incubation using an egg candler. Hatchling data were also recorded; hatching success was recorded together with hatchling survival and hatchling body weights.

Under the conditions of the study there were no statistically significant differences noted in any of the parameters investigated in any of the treatment groups. Therefore, based on the results of this study on mallards, the NOEC of the test material is considered to be 2700 mg a.i./kg diet. Test material levels up to 2700 mg a.i./kg diet had no observed effect on the health, body weight, feed consumption or reproductive performance of adult mallards when administered via the diet for 20 weeks. Also, there were no observed effects noted in egg development or hatchling observations and body weights.

In the study reported by Mach (2003) the effect of the test material on the reproductive performance of Northern Bobwhites was investigated in a study which was conducted under GLP conditions and in accordance with the standardised guidelines OECD 206 and EPA OPP 71-4.

During the study birds were paired (1 male, 1 female); 15 pairs of birds were fed test diets containing test material at concentrations of 0 (plain diet control), 675, 1350 or 2700 mg a.i./kg diet. Diet was presented daily to the birds for 20 consecutive weeks. During the study, the adult birds were observed daily for test-material related effects. Body weights were measured on day 0 and at the end of weeks 2, 4, 6, 8 and 20 (study termination). Feed consumption of each pair was determined weekly. Reproductive parameters included determination of the number of eggs laid per hen and eggshell thickness. Defective and cracked eggs were also recorded. On approximately day 11 of incubation, eggs were candled to determine the viability of the embryos. All embryos considered viable were kept in the incubator for further development. All viable embryos were examined for development at approximately day 18 of incubation using an egg candler. Hatchling data were also recorded; hatching success was recorded together with hatchling survival and hatchling body weights.

Under the conditions of the study there were no statistically significant differences noted in any of the parameters investigated in any of the treatment groups. Therefore, based on the results of this study on mallards, the NOEC of the test material is considered to be 2700 mg a.i./kg diet. Test material levels up to 2700 mg a.i./kg diet had no observed effect on the health, body weight, feed consumption, or reproductive performance of adult Northern bobwhites when administered via the diet for 20 weeks. Also, there were no observed effects noted in egg development or hatchling observations and body weights.