Desmedipham

Toxicity to birds

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2002-01-07 to 2003-09-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 206 (Avian Reproduction Test)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.2300 (Avian Reproduction Test)

Version / remarks:

1996

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

The test substance is a pale powder.

Dose method:

homogenously mixed into feed (accounts for technical substances)

Analytical monitoring:

yes

Vehicle:

no

Details on preparation and analysis of diet:

DIET PREPARATION
- Preparation of doses: Birds were fed a diet containing the test substance at different concentrations: 0 ppm (control), 25 ppm (low dose), 250 ppm (intermediate dose) and 2500 ppm (high dose). Desmedipham was mixed in the diet without solvent or carrier and the diet was prepared freshly each week.

HOMOGENEITY AND STABILITY OF TEST MATERIAL IN DIET
Analyses on homogeneity and stability of the test substance in the diet were performed prior to study initiation. During the test, diet mixtures containing the highest and the lowest concentration of the test substance were analysed. During test weeks 1 and 2, and in test weeks 10 and 11, the concentration and stability was determined immediately after the initial mixing and again within 4 hours of replacing with freshly mixed diet (2 samples per dose level).

- Nominal concentration : Birds were fed a diet containing the test substance at different concentrations: 0 (control), 25, 250 and 2500 ppm.

ANALYTICAL METHODS IN THE FEED
- Separation method: HPLC
- Detection method: UV

Test organisms (species):

Colinus virginianus

Details on test organisms:

TEST ORGANISM
- Common name: Bobwhite quail (Colinus virginianus)
- Age at test initiation : 24 weeks old
- Weight at test initiation : Males (111 – 235 g), females (118 – 219 g)
- Sexes used / mixed or single sex: mixed
- Kept according to standard practices: yes
- Feed: The adults were fed Ssniff® Wachtein-Z V6120.
- Water: Drinking water was provided ad libitum.

Limit test:

no

Total exposure duration (if not single dose):

11 wk

Remarks:

The 22 weeks of the test period were divided into three different phases:
(i) Pre-photostimulation - 8 weeks
(ii) Pre-egg laying (with photostimulation) - 3 weeks
(iii) Egg laying - 11 weeks

No. of animals per sex per dose and/or stage:

In total 128 animals were divided into four groups of 32 birds resulting in 16 pens with one male and one female for each concentration.

Control animals:

yes, plain diet

Nominal and measured doses / concentrations:

Nominal concentrations of 25, 250, and 2500 ppm.

Details on test conditions:

ACCLIMATION
- Acclimation period: 3 weeks

PEN SIZE AND CONSTRUCTION MATERIALS
- Description: The animals were kept in pens as pairs. During the adaptation period and the actual test, adult Bobwhite quails were housed indoors in air-conditioned animal rooms, in galvanised metal pens in pairs of one male and one female. Surface area was 0.25 m2 per bird.
- Compliant to good husbandry practices: yes
- Suitable to avoid crowding stress: yes
- Caging: group

TEST CONDITIONS
- Room temperature: 22°C ± 5°C
- Relative humidity (%): 50 - 75%
- Photoperiod: After start of treatment, the animals were held under short day conditions (7 to 8 hours light per day) for 8 weeks. During this time, the dark period was not interrupted. The photoperiod was then lengthened to 16 – 18 hours of light per day for the rest of the study.

Details on examinations and observations:

The following observations were made during the test; Daily checks were performed on behavior, external appearance and sign of toxicity of the adult birds and the hatchlings. The frequency, duration and description of signs of toxicity, severity, numbers of affected animals and remissions of the effects, are reported.

Body weight of the adult birds was measured at start of exposure to the test material, prior to the onset laying of egg (10 day after start of long-day conditions) and at termination of the study. Body weight of young birds was determined at 14 days of age.

Food consumption of the adults was determined by weighing the residue in one-week intervals throughout the study. For the young birds, food consumption was measured in the first and the second week after hatching.

On day 155 (11 weeks after the start of egg laying) the adult birds were sacrificed by ether, dissected and inspected macroscopically. In addition, gross pathology was conducted on all birds that died during the test period.

Details on reproductive parameters:

Egg sampling
Once laying began, the eggs were collected daily and marked with a felt pen according to the pen.

Incubation and examination of eggs
The eggs were stored and set for incubation every other week, under housing conditions indicated for eggs. Prior to incubation, all eggs were candled to detect cracks. Cracked eggs were not incubated. Eggs set for incubation were candled again on day 11 (to determine fertility and early death of the embryos) and on day 18 (to measure embryo survival) determine viability. At least two eggs from each pen designated in advance (e.g the 3rd and the 10th eggs) were measured for eggshell thickness. Cracked eggs were not measured but their numbers were recorded. The eggs were opened at the girth (widest position), washed out, air-dried with the membrane intact for at least 48 hours and measured at 4 points around the girth using a micrometer calibrated at least to t 0.01 mm units.

Hatching
The eggs were transferred from incubation conditions to hatching conditions on day 21 (see sectio details. Hatching was completed by day 23 to 24. The number of embryos that mature, hatchability, and percentage of 14-day-old survivors, were recorded.

Young birds
Hatchlings were housed in groups according to pen of origin. The hatchlings were maintained on the appropriate diet for at least 14 days. The number of hatchlings, hatchability, percentage of hatchlings per viable 18-day embryos, percentage of 14-day-old survivors, and number of 14-day-old survivors per hen, were recorded and reported. The first 12 egg-laying pens were evaluated neglecting the last surplus pen numbers. Pens in which one partner died prematurely were not used for the overall calculations.

Key result

Duration (if not single dose):

22 wk

Dose descriptor:

NOEL

Effect level:

25 mg/kg bw/day

Conc. / dose based on:

test mat.

Basis for effect:

other: direct toxicity and reproductive endpoints

Mortality and sub-lethal effects:

Mortality and clinical signs
No test substance-related effects were observed on behaviour or external appearance during the whole experimental period for any of the adult birds. In total 5 adult females (1 animal of the control group, 3 animals of the low dose group and 1 animals of the intermediate dose group) died during the course of this study. These deaths were considered as incidental and not treatment related. Treatment of the adult birds at doses up to 2500 ppm did not cause any test substance-related changes in behaviour or external appearance of the young birds. The mortality was between 10 % and 22% in all tested groups including control. Pre-mortal symptoms were regularly noted in form of abdominal and lateral position.

Food consumption
No test substance-related influence on food intake was noted for adult birds at 25 and 250 ppm. At 2500 ppm a marginal reduction of food consumption (by ca. 8%) was noted in weeks 4 and 16 to 18 (statistically significant at p<0.05 in test week 16 only). In comparison to the control group food consumption of young animals was slightly lower in all treatment groups. As however not dose-relationship was evident this finding is not considered to be compound related.

Body weight
No test substance-related influence was observed on the body weight of male and female quails and the body weight gain of females at dose levels up to 2500 ppm. The body weight gain of high dose group males was marginally lower in test weeks 10 and 23 when compared with the respective control group value. The body weight of the 14-day old quails at 25 and 250 ppm was within the normal range of the controls. At 2500 ppm the mean body weight of the young quails was 13.4% lower compared to the control (statistically significant at p<0.01)

Effects on reproduction:

At the high dose (2500 ppm) egg production per hen was reduced by 25.4% as compared to the control (no statistical significance). As a result, the number of viable eggs per hen, the number of eggs set per hen and the numbers of viable embryos per hen were reduced by 23.3 to 26.9%, all parameters were not significant). The number of viable embryos on day 11 and 18, the number of hatchlings per hen and the number of 14-day survivors per hen were also reduced. The mean % of viable embryos per eggs set, the % of live 11- day embryos per eggs set and live 18-day embryos per viable embryos, the % of hatchlings per eggs set and the mean % of hatchlings surviving for 14 days were not influenced at 2500 ppm. No test substance-related effect was noted for the ratio of viable 18-day embryos versus viable 11-day embryos per pen, the eggshell thickness and % of cracked eggs.

Further details on results:

Analytical results
The results of the analyses showed that the test substance-diet mixtures were correctly prepared (range 88.9% to 113.0% of nominal value) and that concentrations, homogeneity (92 - 113%) and stability (88 - 112%) were in good agreement to those expected.

See "Attachments" in "Overall remarks, attachments" for a summary of the effect of desmedipham on reproduction parameters of the bobwhite quail.

Validity criteria fulfilled:

yes

Conclusions:

The test followed the OECD guideline 206 and the validity criteria were met: less than 10% mortality in control and the concentration of the substance was above 80 per cent of the nominal. Also, the average number of 14-day-old survivor per hen was above 12 and average eggshell thickness for the control group was =0.19 mm. Thus, the study is considered valid. There were no test substance-related effects on the behaviour, body weight and food consumption of the parental animals of the low (25 ppm) and intermediate (250 ppm) dose group. Only a marginal reduction of the body weight gain was noted for the male animals of the high dose group (2500 ppm). Treatment with 25 and 250 ppm desmedipham revealed no influence on the reproductive parameters of Bobwhite quails. Treatment with 2500 ppm desmedipham led to slight effects on egg production (reduction by 25.4% when compared with the control). Therefore, the NOEL for adult birds is set at 250 ppm based on lower food consumption and lower body weights at 2500 ppm, for reproduction at 250 ppm based on a lower number of eggs produced at 2500 ppm, and for young birds at 250 ppm based on lower body weights of chicks at 2500 ppm. The NOEL 250 ppm corresponds to 25 mg a.s./kg bw/d.

Executive summary:

The effects of desmedipham to the bobwhite quail (Colinus virginianus) were determined in a 22-week reproduction toxicity test. Mortality, body weight, food consumption, reproductive parameters, and any other overt signs of toxicity, were assessed at nominal dietary concentrations of 0 (control), 25, 250, and 2500 ppm. It was concluded that the 250 ppm test concentration (equivalent to an achieved daily intake of 25 mg a.s./kg body weight/day) was the NOEL for bobwhite quails exposed to desmedipham in the diet.

Reference 2

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1994-05-19 to 1995-01-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 71-4 (Avian Reproduction Test)

Version / remarks:

October, 1982

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

The test substance is a white powder.

Dose method:

homogenously mixed into feed (accounts for technical substances)

Analytical monitoring:

yes

Vehicle:

no

Details on preparation and analysis of diet:

DIET PREPARATION
- Preparation of doses: Test diets were prepared weekly from premixes containing the test substance mixed with a small quantity of basal diet. Each required nominal dietary concentration of the test substance was prepared from a portion of the premix by further addition of basal diet. When needed during the test, additional diet was prepared.

HOMOGENEITY AND STABILITY OF TEST MATERIAL IN DIET
- How often was homogeneity tested: Homogeneity of the test substance in the diet was evaluated by collecting three samples each from the treatment groups on Day 0 of Week 1. Homogeneity samples were collected from the top, middle and bottom of the mixing vessel.
- How often was stability tested: Diet samples were collected from the control group and each treatment group after being held for 2, 4, 8 and 15 days to verify the presence of the test substance under actual test conditions. Analyses were performed on diet samples collected on Days 4 and 8.
- When and at what dose levels were samples of treated food analyzed for stability and concentration during the study: At each weekly diet preparation with the exception of Weeks 13 and 15, a sample was collected from the control group and each treatment group to verify test substance concentrations in the diets. During Weeks 13 and 15, samples were collected from the remaining diet at Day 7. Analyses were performed on diet samples collected during Weeks 1, 4, 8, 12, 16 and 20. Additional diet was prepared on three occasions during the test, but was not sampled or analyzed.
- Nominal concentration (mg/kg feed): Birds were fed a diet containing the test substance at different concentrations: 0 ppm (control), 90, 450 and 2000 ppm corresponding to 0, 11, 61 and 248 mg a.s./kg bw/day.


ANALYTICAL METHODS IN THE FEED
- Separation method: HPLC
- Detection method: UV

Test organisms (species):

Colinus virginianus

Details on test organisms:

TEST ORGANISM
- Common name: Bobwhite quail (Colinus virginianus)
- Age at test initiation : 20 weeks old
- Weight at test initiation : 180 - 223 g
- Sexes used / mixed or single sex: mixed
- Disease free: At test initiation, all birds were examined for physical injuries and general health. Birds that did not appear healthy were discarded.
- Kept according to standard practices: yes
- Breeding population (e.g. reproductive history): The birds were approaching their first breeding season and had not been used in previous testing.
- Feed: The adults were fed a game bird diet, formulated for breeding birds.
- Water: Domestic quality potable drinking water was also available ad libitum throughout the study.

Limit test:

no

Total exposure duration (if not single dose):

10 wk

Remarks:

The 21 weeks of the test period were divided into three different phases:
(i) Pre-photostimulation - 7 weeks
(ii) Pre-egg laying (with photostimulation) - 4 weeks
(iii) Egg laying - 10 weeks

Post exposure observation period:

6 weeks

No. of animals per sex per dose and/or stage:

A total of 128 animals were divided into four groups of 32 birds resulting in 16 pens with one male and one female for each concentration.

Control animals:

yes, plain diet

Nominal and measured doses / concentrations:

Nominal concentrations of 90, 450 and 2000 ppm (equivalent to 10, 46 and 254 mg/kg bw/d)

Details on test conditions:

ACCLIMATION
- Acclimation period: 3 weeks

PEN SIZE AND CONSTRUCTION MATERIALS
- Description: The adult birds were housed indoors, in one room, in batteries of pens.
- Floor covering: Each pen had galvanized wire grid walls, floor and ceiling. The floor area was about 30 x 51 cm.
- Compliant to good husbandry practices: yes
- Suitable to avoid crowding stress: yes
- Caging: group

TEST CONDITIONS
- Room temperature: 21.8°C ± 1.5°C
- Relative humidity (%): 67 ± 15%
- Photoperiod: The room photoperiod for the first 7 weeks of the study was eight hours of light per day. During Week 8, it was increased to seventeen hours of light per day and was maintained at that length until euthanasia of adult birds.
-Light intensity: 410 lux
- Ventilation: The air handling system in the study room was designed to vent up to fifteen room air volumes every hour and replace it with fresh air.

Details on examinations and observations:

All adult birds were observed at least once daily throughout the study for signs of toxicity or abnormal behavior. A record was maintained for all mortalities and observations. All birds that died during the study were necropsied. As soon as practical after the death of the bird, the penmate was sacrificed and necropsied.
Birds were weighed individually at the start of the treatment period (Day 0 of Week 1), on Weeks 2, 4, 6 and 8 and at terminal sacrifice. Body weights were not measured during egg laying because of the possible adverse effects handling may have on egg production.

Feed consumption was measured for each pen for a seven-day period every week and is presented on a weekly basis. Feed consumption was determined by weighing the freshly filled feeder when presented to the birds, recording the amount of any additional diet added during the week, and weighing the feeder and remaining feed at the end of the feeding period. No attempt was made to quantify the amount of feed wasted by the birds, as the wasted feed is normally scattered and mixed with water and excreta.

At necropsy, records of the external appearance and macroscopic abnormalities of tissues and organs of the thoracic and abdominal cavities were made for adult birds dying or euthanized during the course of the test and for those surviving to termination

Details on reproductive parameters:

Incubation; eggs were set for incubation on a weekly basis. The eggs were placed in a Petersime incubator (Model No. SP20) for 21 days where the temperature was maintained at an average of 37.5°C ± 0.0°C with an average wet bulb temperature of approximately 29.4°C ± 0.0°C (an average relative humidity of approximately 56%). During several instances, the temperature was outside the specified range and rechecked. The rechecked values were used for the calculation of means and standard deviations, while both temperatures were reported on the temperature log. The incubator was equipped with a pulsator fan and blades that produced a mild breathing air movement designed to eliminate intracabinet temperature and humidity variation during incubation. In order to prevent adhesion of the embryo to the shell membrane, an automatic egg rotation device within the incubator rotated the eggs each hour from 50° off of vertical in one direction to 50° off of vertical in the opposite direction (total arc of rotation is 100°). On Day 21 of incubation, the eggs were transferred to the hatcher.

Eggs and Embryos; records were maintained for each pen and each week of the numbers of eggs that were laid, cracked, abnormal, set and hatched and the numbers of viable and live three week embryos. Egg shell thickness was recorded for each pen and week as appropriate.

Offspring; records were kept of the numbers of hatchlings and chicks surviving for 14 days (14-day survivors) per pen, per week. Offspring body weights were determined at hatching and at 14 days of age for surviving chicks.

Key result

Duration (if not single dose):

21 wk

Dose descriptor:

NOEL

Effect level:

46 mg/kg bw/day

Conc. / dose based on:

test mat.

Basis for effect:

reproductive parameters

Mortality and sub-lethal effects:

Mortality
One incidental mortality occurred both in the control group and the 450 ppm treatment group, two incidental mortalities occurred in 2500 ppm treatment group and three incidental mortalities occurred in 90 ppm treatment group. One bird both in 90 and 2500 ppm group exhibited clinical signs prior to death. Due to the nature of the lesions observed at necropsy, none of the above mortalities was considered to be treatment related.

Clinical Observations
No other overt signs of toxicity were observed at any dose level tested. Except for incidental clinical findings, all birds appeared normal throughout the test.

Body weight
There were no treatment related effects upon body weight at the 90 or 450 ppm concentrations. At the 90 ppm test concentration there was a slight reduction in the body weight of males at the week 4 body weight interval that was statistically significant at p<0.05. However, since the difference was very slight, isolated to that one body weight interval and not concentration responsive, the difference observed was not considered to be treatment related. At the 2500 ppm concentration, there was a slight but statistically significant reduction in body weight of males from week 8 until the end of the experiment. In postmortem examination there appeared to be a slight increase in the number of birds that exhibited a friable liver at 2500 ppm concentration.

Feed consumption
There were no treatment related effects upon feed consumption at the 90, 450 or 2500 ppm treatment groups.

Effects on reproduction:

There were no statistically significant effects of desmedipham treatment on the reproduction performance of Bobwhite quail. However, while not statistically significant, the 2500 ppm treatment group appeared to show a slight reduction number of eggs laid during the first two weeks of egg production. This was a consequence of a slight decrease the number of females that came into egg production during the first portion of the egg laying period, and not a reduction in the number of eggs laid by those females that were production. There were no other treatment related effects upon reproductive performance at the 2500 ppm test concentration, and the slight delay in the onset of egg production did not impact on reproductive success.

Further details on results:

Analytical results
The analytical method for desmedipham in avian diet yielded to an overall mean procedural recovery of 94%. The measured concentration of desmedipham in the diet, corrected for procedural losses, ranged from 9 to 106% of the nominal.

See "Attachments" in "Overall remarks, attachments" for tables and figures.

Validity criteria fulfilled:

yes

Conclusions:

The study followed the OECD guideline 206 and the validity criteria were met: less than 10 % mortality in control and the concentration of the substance was above 80 per cent of the nominal. Also, the average number of 14-day-old survivor per hen was above 12 and average eggshell thickness for the control group was =0.19. Thus, the study is considered valid. There was a slight delay in the onset of egg production at 2500 ppm concentration level, but no statistical effect on reproductive success. There was also a slight but statistically significant reduction in body weight of males from week 8 until the end of the experiment at the 2500 ppm concentration. In addition, the postmortem examination revealed a slight increase in the number of birds that exhibited a friable liver at 2500 ppm concentration. Therefore, the NOEL is set at 450 ppm diet corresponding to 46 mg a.s./kg bw/day.

Executive summary:

The effects of desmedipham to the bobwhite quail (Colinus virginianus) were determined in a 21-week reproduction toxicity test. Mortality, body weight, food consumption, reproductive parameters, and any other overt signs of toxicity, were assessed at nominal dietary concentrations of 0 (control), 90, 450 and 2000 ppm. It was concluded that the 450 ppm test concentration (equivalent to an achieved daily intake of 46 mg a.s./kg body weight/day) was the NOEL for bobwhite quails exposed to desmedipham in the diet.

Reference 3

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-06-08 to 1995-01-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 71-4 (Avian Reproduction Test)

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

The test material is a white powder.

Dose method:

homogenously mixed into feed (accounts for technical substances)

Analytical monitoring:

yes

Vehicle:

no

Details on preparation and analysis of diet:

DIET PREPARATION
- Preparation of doses: Test diets were prepared weekly from premixes containing the test substance mixed with a small quantity of basal diet. Each required nominal dietary concentration of the test substance was prepared from a portion of the premix by further addition of basal diet. When needed during the test, additional diet was prepared.


HOMOGENEITY AND STABILITY OF TEST MATERIAL IN DIET
- How often was homogeneity tested: Homogeneity of the test substance hi the diet was evaluated by collecting three samples each from the treatment groups on Day 0 of Week 1. Homogeneity samples were collected from the top, middle and bottom of the mixing vessel.
- How often was stability tested: Diet samples were collected from the control group and each treatment group after being held for 2, 4, 8 and 15 days to verify the presence of the test substance under actual test conditions.
- When and at what dose levels were samples of treated food analyzed for stability and concentration during the study: At each weekly diet preparation with the exception of Weeks 13 and 15, a sample was collected from the control group and each treatment group to verify test substance concentrations in the diets. During Weeks 13 and 15, samples were collected from the remaining diet at Day 7. Analyses were performed on diet samples collected during Weeks 1, 4, 8, 12, 16 and 20. Additional diet was prepared on three occasions during the test, but was not sampled or analyzed.
- Nominal concentration: Birds were fed a diet containing the test substance at different concentrations: 0 ppm (control), 90, 450 and 2000 ppm corresponding to 0, 11, 61 and 248 mg a.s./kg bw/day.


ANALYTICAL METHODS IN THE FEED
- Separation method: HPLC
- Detection method: UV

Test organisms (species):

Anas platyrhynchos

Details on test organisms:

TEST ORGANISM
- Common name: Adult mallard ducks (Anas platyrhynchos)
- Age at test initiation : 18 weeks old
- Weight at test initiation : 877g to 1298 g
- Sexes used / mixed or single sex: mixed
- Disease free: At test initiation, all birds were examined for physical injuries and general health. Birds that did not appear healthy were discarded.
- Kept according to standard practices: yes
- Breeding population (e.g. reproductive history):The birds were approaching their first breeding season and had not been used in previous testing.
- Feed: The adults were fed a game bird diet, formulated for breeding bird.
- Water: Domestic quality potable drinking water was also available ad libitum throughout the study.

Limit test:

no

Total exposure duration (if not single dose):

11 wk

Remarks:

The 22 weeks of the test period were divided into three different phases:
(i) Pre-photostimulation - 8 weeks
(ii) Pre-egg laying (with photostimulation) - 2 weeks
(iii) Egg laying - 11 weeks

Post exposure observation period:

11 weeks

No. of animals per sex per dose and/or stage:

A total of 128 adult mallards were divided into four groups of 32 birds resulting in 16 pens with one male and one female for each concentration.

Control animals:

yes, plain diet

Nominal and measured doses / concentrations:

Nominal concentrations of 90, 450 and 2000 ppm (equivalent to 11, 61 and 248 mg/kg bw/d)

Details on test conditions:

ACCLIMATION
- Acclimation period: 2 weeks

PEN SIZE AND CONSTRUCTION MATERIALS
- Description: The adult birds were housed indoors, in one room, in batteries of pens measuring approximately 75 x 90 x 45 cm high.
- Floor covering: The floors, walls and ceilings of the pens were constructed of galvanized wire grid.
- Compliant to good husbandry practices: yes
- Suitable to avoid crowding stress: yes
- Caging: group


TEST CONDITIONS
- Room temperature: 23.5°C ± 2.8°C
- Relative humidity (%): 69 ± 14%
- Photoperiod: The room photoperiod for the first 8 weeks of the study was eight hours of light per day. During Week 9, it was increased to seventeen hours of light per day and was maintained at that length until euthanasia of adult birds
- Ventilation: The air handling system in the study room was designed to vent up to fifteen room air volumes every hour and replace it with fresh air


RANGE FINDING STUDY
- Test concentrations: Dietary concentrations of 0, 625, 1250 or 2500 ppm of Technical desmedipham.
- Test conditions: The birds were housed indoors in batteries of pens. Each pen had floor space that measured approximately 72 X 90 X 45 cm high. The pens were constructed of vinyl-coated wire mesh. Each pen was equipped with a feeder. Each week, sufficient feed for seven days was placed in feeders for each pen and presented to the birds. Water was supplied by nipple type waterers. The birds were maintained in a manner which helped avoid excessive disturbances. The average temperature in the study room during the test was 19.2°C ± 1.1°C (SD), with an average relative humidity of 59% ± 15% (SD). The air handling system in the study room was designed to vent up to 15 room air volumes every hour and replace it with fresh air. The photoperiod in the study room was maintained by a time clock at seventeen hours of light per day. The birds were exposed to a mean of approximately 289 lux of illumination throughout the test, provided by Chroma 50 or equivalent fluorescent lights which closely approximate noon-day sunlight (noon-day sun - 4870* Kelvin, Chroma 50 - 5000° Kelvin").
- Results used to determine the conditions for the definitive study: In a six-week dietary reproduction range finding study conducted previously, there was a loss of body weight and unpaired egg production at 2500 ppm. A slight loss of body weight was indicated at 1250 ppm, however, the small group size precluded conclusive evaluation of this response. Dietary administration of up to 625 ppm of Technical desmedipham to mallard ducks had no effect on adult birds. It was considered that the high dose level in the subsequent dietary reproduction study in this species should be slightly less than 2500 ppm Technical desmedipham.

Details on examinations and observations:

All adult birds were observed at least once daily throughout the study for signs of toxicity or abnormal behavior. A record was maintained for all mortalities and observations. Birds were weighed individually at the start of the treatment period (Day 0 of Week 1), on Weeks 2, 4, 6 and 8 and at adult termination. At the Sponsor's request to monitor any additional changes in body weight loss at the 2000 ppm test concentration, body weights of the adults in the control and 2000 ppm treatment groups were measured at the end of Week 10. Body weights were not measured during egg laying because of the adverse effects handling may have on egg production. Feed consumption was measured weekly for each pen and is presented on a weekly basis. The feed consumption interval for Week 22 was 4 days. Feed consumption was determined by weighing the freshly filled feeder when presented to the birds, recording the amount of any additional diet added during the week, and weighing the feeder and remaining feed at the end of the feeding period. No attempt was made to quantify the amount of feed wasted by the birds, as the wasted feed is normally scattered and mixed with water and excreta. At necropsy, records of the external appearance and macroscopic abnormalities of tissues and organs of the thoracic and abdominal cavities were made for adult birds dying or euthanized during the course of the test and for those surviving to termination.

Details on reproductive parameters:

Incubation; eggs were set for incubation on a weekly basis. The eggs were placed in a Petersime incubator for 24 days where the temperature was maintained at an average of 37.5°C ± 0.0°C (SD) with an average wet bulb temperature of approximately 29.4°C ± 0.0°C (SD) (an average relative humidity of approximately 56%). During several instances, the temperature was outside the specified range and rechecked. The rechecked values were used for the calculation of means and standard deviations, while both temperatures were reported on the temperature log. The incubator was equipped with a pulsator fan and blades that produced a mild breathing air movement designed to eliminate intracabinet temperature and humidity variation during incubation. In order to prevent adhesion of the embryo to the shell membrane, an automatic egg rotation device within the incubator rotated the egg each hour from 50° off of vertical in one direction to 50° off of vertical in the opposite direction (total arc of rotation is 100°). On Day 24 of incubation, the eggs were transferred to the hatcher.

Eggs and Embryos; eggs were candled for cracks and abnormalities prior to incubation on Day 14 or 15 of incubation to determine embryo viability and on Day 21 for embryo survival. Eggs that did not contain viable embryos were recorded and discarded. Records were maintained for each pen and each week of the numbers of eggs that were laid, cracked, abnormal, set and hatched and the numbers of viable and live three week embryos. Egg shell thickness was recorded for each pen and week as appropriate.

Offspring; on Day 24 of incubation, the eggs were placed by pen in galvanized steel wire mesh pedigree baskets in a Petersime Hatcher. Eggs were not rotated in the hatcher. All hatchlings, unhatched eggs and egg shells were removed from the hatcher on Day 27 or 28 of incubation. Records were kept of the numbers of hatchlings and offspring surviving for 14 days (14-day survivors) per pen, per week. Offspring body weights were determined at hatching and at 14 days of age for surviving ducklings.

Key result

Duration (if not single dose):

22 wk

Dose descriptor:

NOEL

Effect level:

11 mg/kg bw/day

Conc. / dose based on:

test mat.

Basis for effect:

reproductive parameters

Mortality and sub-lethal effects:

Mortality and sub-lethal effects

MORTALITY
No mortalities occurred in the control group or in the 90 ppm treatment group. While no treatment related mortalities occurred in the 450 ppm treatment group, one incidental mortality did occur. Thirteen mortalities occurred in the 2000 ppm treatment group, seven males and six females. All thirteen of the mortalities were attributed to treatment.

CLINICAL SIGNS
At the 90 ppm test concentration, one female was noted standing and walking on her toes during weeks 11, 12 and 13 only. The authors stated that such observations occasionally are noted as incidental findings in mallard reproduction studies. No other treatment related overt signs of toxicity were observed at 90 ppm test concentration. At 450 ppm test concentration five birds displayed clinical signs of toxicity that may have been related to treatment. At 2000 ppm concentration, signs of toxicity typically observed prior to death including e.g. loss of coordination, lower limb weakness, lethargy, reduced reaction to external stimuli, ruffled appearance, and lower limb rigidity were observed. Necropsy findings typically included emaciation, with most birds weighing less than 700 grams.

BODY WEIGHT
There were no treatment related effects upon body weight at the 90 ppm test concentration. Although not statistically significant, there was a slight transient treatment related loss of male body weight at the 450 ppm test concentration from test initiation until the week 2 body weight interval. At the 2000 ppm test concentration there were profound effects upon adult body weight.

FOOD CONSUMPTION
There were no treatment related effects upon feed consumption at the 90 and 450 ppm test concentration. At the 2000 ppm test concentration, there was a marked treatment related reduction in feed consumption.

PATHOLOGY
All surviving adults were subjected to gross necropsy following adult termination. At the 2000 ppm test concentration there was an increase in the number of females that displayed an ovary with no mature follicles and multiple yellow follicles 5: 1 cm, a reflection of the fact that most females in that group had never been hi egg production. All other findings were considered incidental to treatment.

Effects on reproduction:

Reproduction Data

Egg Production, Embryo Viability, Hatching, and Offspring Survival
There were no treatment related effects upon overall reproductive performance at the 90 ppm test concentration, and any differences in reproductive measurements between the control group and the 90 ppm treatment group was not statistically significant. The single female at the 90 ppm test concentration that was noted walking on her toes also showed a slight reduction in egg production, laying only 15 eggs compared to a control average of 41 eggs per female. However, the reduction was within the limits of variability observed in the control group.

There were no effects upon overall egg production in the 450 ppm treatment group. Two of the three females that displayed clinical signs of toxicity also showed a reduction in egg production. While not statistically significant, there also appeared to be a slight reduction in viable embryos as a percent of eggs set. The reduction was slight, and was confined to only four pens. However, the two pens with 0% and 50% viability were also the two pens in which the males exhibited clinical signs of toxicity. Therefore, a treatment related effect could not be precluded. There were no other effects upon the reproductive parameters measured at the 450 ppm test concentration.

At the 2000 ppm test concentration there were profound effects upon reproductive performance. Although birds in the 2000 ppm treatment group received control or basal diet from Week 14 until adult termination, only two of the 10 surviving hens laid eggs, none of which were viable. Therefore, it was impossible to assess reproductive effects on other parameters. Reproductive data are presented in Tables 3 and 4, and Figures 4 and 5.

Egg Shell Thickness
There were no apparent treatment related effects upon egg shell thickness at the 90 ppm test concentration, and any differences from the control group were not statistically significant. At the 450 ppm test concentration there was a slight, but statistically significant (p<0.05) reduction in egg shell thickness. At the 2000 ppm test concentration there were insufficient eggs to accurately assess effects upon this parameter. Egg shell thickness data are presented in Table 5.

Offspring Body Weights
There were no treatment related effects upon the body weights of hatchlings or 14-day old survivors at the 90 or 450 ppm test concentrations. When compared to the control group, there were no statistically significant differences in offspring body weight hi either of those treatment groups. No offspring were produced at the 2000 ppm test concentration. Offspring body weight data are presented in Table 6.

Further details on results:

The achieved intake of test substance at 0, 90, 450 and 2000 ppm was 0, 11, 61 and 248 mg desmedipham/Kg body weight/day, respectively.

There were no apparent effects upon mortality, body weight, feed consumption, or overall reproductive performance at the 90 ppm concentration. One female transiently displayed a clinical sign that was associated with toxicity at higher concentrations. However, this finding is also seen to occur spontaneously from time to time in control populations.

The 450 ppm treatment group exhibited no effects on mortality, feed consumption or overall reproductive performance, although five birds displayed clinical signs of toxicity, and there was a slight, but not statistically significant, reduction in embryo viability in four pens and slight reduction in egg shell thickness. Males in the 450 ppm treatment group also showed a slight (overall 2 gram mean) loss of body weight during the first two weeks of the test.

At the 2000 ppm test concentration there were profound effects upon all parameters measured. Thirteen of 32 birds died as a result of treatment, overt signs of toxicity were observed in all surviving birds, and there were marked effects on adult body weight and feed consumption. Additionally, only 31 eggs were laid, and none of the 26 eggs set for incubation were fertile. Although the birds received control diet from Week 14 until adult termination, mortalities continued to be observed through Week 18, and only moderate recovery was observed hi those birds that survived.

See "Attachments" in "Overall remarks, attachments" for tables and figures.

Validity criteria fulfilled:

yes

Conclusions:

The test followed the OECD guideline 206 and the validity criteria were met: less than 10% mortality in control and the concentration of the substance was above 80 per cent of the nominal. Also, the average number of 14-day-old survivor per hen was above 14 and average eggshell thickness for the control group was = 0.34. Hence, the study is considered valid. A single female at the 90 ppm test concentration that was noted walking on her toes also showed a slight reduction in egg production, laying only 15 eggs compared to an average of 41 eggs per female in control. However, the reduction was within the limits of variability observed in the control group. The 450 ppm treatment group exhibited no effects on mortality, feed consumption or overall reproductive performance, although five birds displayed clinical signs of toxicity, and there was a slight, but not statistically significant, reduction in embryo viability in four pens and slight reduction in egg shell thickness. Males in the 450 ppm treatment group also showed a slight loss of body weight (overall 2 gram mean) during the first two weeks of the test. Therefore, the NOEC is set at 90 ppm diet corresponding to 11 mg a.s./kg bw/day.

Executive summary:

The effects of desmedipham to the mallard duck (Anas platyrhynchos) were determined in a 22-week reproduction toxicity test. Mortality, body weight, food consumption, reproductive parameters, and any other overt signs of toxicity, were assessed at nominal dietary concentrations of 0 (control), 90, 450 and 2000 ppm. It was concluded that the 90 ppm test concentration (equivalent to an achieved daily intake of 11 mg a.s./Kg body weight/day) was the no observed effect concentration for mallard ducks exposed to technical desmedipham in the diet.

Description of key information

The objective of the study was to investigate the effect of dietary exposure of Desmedipham on Mallard duck's reproduction. Birds were fed a diet containing the test item in concentrations of 11, 61 and 248 mg/Kg bw/d for a period of 22 weeks. The NOEC was determined to be 11 mg/kg bw/d.

In the table below all available studies are listed. For some studies only the results are presented since they are not considered relevant due to the reasons given under “Assessment”. All available studies have been evaluated within the scope of Plant Protection Regulation in the respective Draft Renewal Assessment Report (DAR) under Regulation (EC) 1107/2009.

Test species	Result	Assessment	Reference
Anas platyrhynchos (Mallard duck)	22-w NOEC = 11 mg/kg bw/d	Key study	Beavers et al. (1995)
Colinus virginianus (Bobwhite quail)	21-w NOEL = 46 mg/kg bw/d	Supporting study	Beavers et al. (1995)
Colinus virginianus (Bobwhite quail)	22-w NOEL = 25 mg/kg bw/d	Supporting study	Leuschner (2003)
Colinus virginianus (Bobwhite quail)	14-d LD50 >2000 mg/kg bw	This is an acute oral toxicity study. Such study is not a data requirement.	Hakin & Johnson (1990)
Colinus virginianus (Bobwhite quail)	14-d LD50 >2000 mg as/kg bw	This is an acute oral toxicity study. Such study is not a data requirement.	Hakin & Norman (1990)
Anas platyrhynchos (Mallard duck)	14-d LD50 >2000 mg as/kg bw	This is an acute oral toxicity study. Such study is not a data requirement.	Hakin & Norman (1990)
Colinus virginianus (Bobwhite quail)	5-d LDD50 > 483 mg a.s./kg bw/d	This is a short-term toxicity study. Such study is not a data requirement.	Fletcher (1982)
Colinus virginianus (Bobwhite quail)	5-d LDD50 > 1011 mg a.s./kg bw/d	This is a short-term toxicity study. Such study is not a data requirement	Hakin et al. (1990)
Colinus virginianus (Bobwhite quail)	5-d LDD50 > 1435 mg a.s./kg bw/d	This is a short-term toxicity study. Such study is not a data requirement	Beavers et al. (1991)
Anas platyrhynchos (Mallard duck)	5-d LDD50 > 1117 mg a.s./kg bw/d	This is a short-term toxicity study. Such study is not a data requirement	Fletcher (1982)
Anas platyrhynchos (Mallard duck)	5-d LDD50 > 593 mg a.s./kg bw/d	This is a short-term toxicity study. Such study is not a data requirement	Hakin et al. (1990)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for birds:

11 mg/kg bw/day