Pyrasulfotole

Toxicity to birds

Description of key information

For all studies no statistical significant effects were observed up to the highest test item concentrations.

Additional information

Five experimental studies on the toxicity of the test item to birds according to GLP are available.

One study was investigating acute oral toxicity to quail species (Northern bobwhite; M-264120-01-1), two studies were investigating subacute dietary toxicity in quail or mallard species (Northern bobwhite M-259267-01-1 and mallard M-259274-01-1) and two studies investigating the subchronic and reproductive toxicity to birds (Northern bobwhite M-266832-01-1 and mallard M-267171-01-1, respectively). For all studies no statistical significant effects were observed up to the highest test item concentrations.

For the acute oral toxicity study (M-264120-01-1) 18 weeks old adults quail species (Northern bobwhite, 10 per test level, 5 per sex) were single orally dosed with the test item based on body weight at dose levels of 125, 250, 500, 1000, and 2000 mg a.i./kg body weight according to the guideline USEPA FIFRA 71-1, OPPTS 850.1300 (Draft), OECD 205. There was a 14-day post-dose monitoring period. During this period body weights, feed consumption, and health were monitored. No treatment related effects were seen in northern bobwhite. No clinical signs of toxicity were noted at any of the dose levels. No mortalities occurred in any of the dose levels. No effect was seen in body weight, growth, or feed consumption. Postmortem examinations revealed no gross lesions or unusual observations. Based on the results of this study, the single oral dose LD50 of the test item in northern bobwhite is >2000 mg a.i./kg body weight. Based on the parameters measured and observed, the NOEC was 2000 mg a.i./kg body weight and the LOEC was >2000 mg a.i./kg body weight.

For the subacute dietary toxicity in birds two experimental studies were performed using Northern bobwhite (M-259267-01-1) and mallard (M-259274-01-1) as test species according to the guideline USEPA FIFRA 71-2, OPPTS 850.2200 (Draft), OECD 205. The Northern bobwhite study (M-259267-01-1), Colinus virginianus, (10-day-old hatchlings, 10 hatchlings per test level) were exposed for 5 days to dietary concentrations of 0 (control), 313, 625, 1250, 2500, 5000 mg a.i./kg. The exposure was followed by a subsequent 3-day observation period on untreated feed. The measured concentrations in the diet were 0 (<30), 308, 591, 1247, 2813, and 4911 mg a.i./kg feed and the mean daily dietary dose was 0, 58, 109, 232, 517, and 892 mg a.i./kg bw/day, respectively. No clinical signs of toxicity or treatment-related mortalities were noted at any treatment level. There were no statistically significant reductions in body weight or growth during the exposure period at any treatment level. There was no treatment related reduction in feed consumption at any treatment level. Postmortem examinations revealed no treatment related gross lesions or unusual observations. The dietary LC50 of the test item in Northern Bobwhite was >4911 mg a.i./kg feed. Based on all parameters measured, the NOAEL was 4911 mg a.i./kg feed and the LOAEL was >4911 mg a.i./kg feed.

Young mallards, Anas platyrhynchos, (10-day-old ducklings, 10 ducklings per test level) were exposed in study M-259274-01-1 for 5 days to feed with measured dietary concentrations of 0 (control), 306, 605, 1275, 2657 and 5089 mg a.i./kg feed or daily dietary doses of 0, 75, 143, 280, 597, and 1067 mg a.i./kg bw/day. The exposure period was followed by 3-day subsequent recovery phase on untreated feed. Analysis of the test item in the treated bird feed ranged from 97 to 106% of nominal. All designations of treatment concentrations were based on the mean measured concentrations. There were no clinical signs of sub-lethal effects or treatment-related mortality. Some statistically significant differences in body weight were observed at the measured concentrations of 2657 and 5089 mg a.i./kg feed during the treatment period. However, these changes were not considered an adverse effect since the treatment groups gained more weight than the control group. Food consumption was normal during the study period for all treatment levels. Postmortem examinations revealed no treatment related gross lesions or unusual observations. The sub-acute dietary LC50 of the test item in mallards was >5089 mg/kg. Based on all parameters measured, the NOAEL was 5089 mg/kg and the LOAEL was >5089 mg/kg.

 

Two studies were performed for investigating subchronic and reproductive toxicity to birds. Northern bobwhite (M-266832-01-1) and mallard (M-267171-01-1) were used as test species according to the guidelines USEPA FIFRA 71-4, OPPTS 850.2300, OECD 206 and OECD 205.

Young northern bobwhite quail (M-266832-01-1, Colinus virginianus, 16 weeks old when introduced to the test item treated feed), were exposed to the test item for approximately 22 weeks to mean measured dietary concentrations of control (<30), 64, 205, 594 mg a.i./kg feed which corresponds to the nominal dietary concentrations of 0, 67, 200 and 600 mg a.i./kg. The daily dietary dose was 0, 6, 19 and 54 mg a.i./kg bw/day, respectively. There were 18 pairs of birds at each treatment level. Twenty different parameters encompassing adult, reproductive, and hatchling endpoints were examined in this study. In addition, birds were observed for abnormal behaviour and signs of toxicity, gross pathology was conducted, and mortality recorded. There were no compound related symptoms of toxicity in the adults and offspring. While statistically significant differences from the control were observed for four parameters, they were deemed not to be biologically significant nor treatment related due to the lack of a clear dose response and small size of the differences. The NOEC was 594 mg a.i./kg feed. There were no statistically significant adverse effects on any reproductive endpoint. The NOEC was 594 mg a.i./kg feed. There were no compound related findings. The NOEC was 594 mg a.i./kg feed. There were no statistically and biologically significant adverse effects on the adults or on the offspring. The NOAEC was 594 mg a.i./kg feed or 54 mg a.i./kg bw/day.

Adult mallard (M-267171-01-1, Anas platyrhynchos, 19 weeks old when introduced to the test item treated feed), were exposed to the test item for approximately 20 weeks to mean measured dietary concentrations of control (<30), 56, 167, 557 mg a.i./kg feed which corresponds to the nominal dietary concentrations of 0, 67, 200 and 600 mg a.i./kg. The daily dietary dose was 0, 5, 17 and 55 mg a.i./kg bw/day, respectively. There were 15 pairs of birds at each treatment level. Birds were observed for mortality, abnormal behaviour and signs of toxicity; adult body weight and feed consumption were measured; gross pathology was conducted; reproductive parameters, as well as hatchling health, growth and survival, were examined. There were no compound related symptoms of toxicity in the adults and offspring. There were no statistically significant adverse effects on any reproductive endpoint. There were no compound related findings. The NOEC was 557 mg a.i./kg feed. There were no statistically significant adverse effects on the adults or on the offspring. The NOEC was >= 557 mg a.i./kg feed or >= 62 mg a.i./kg bw/day.