1,2,4-triazole

Endpoint summary

Description of key information

NOAEL (oral) = 500 ppm of 1,2,4-triazole in feed (37.85 mg/kg bw/d in males ; 54.20 mg/kg bw/d in females).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Oct. 1, 1978 to Oct. 10, 1979

Reliability:

1 (reliable without restriction)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Version / remarks:

- reliability scoring based on 1998 guideline.

Deviations:

no

GLP compliance:

no

Remarks:

Study predates GLP.

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Winkelmann, Borchen
- Age at study initiation: ~ 5 to 6 weeks old
- Weight at study initiation: 82 g (males) and females 78 g (females)
- Housing: Singly & conventionally in Makrolon cages type II (SPIEGEL and GOENNERT, 1961) on dust-free wood granulate
- Diet (e.g. ad libitum): Altromin powdered feed, ad libitum
- Water (e.g. ad libitum): Not precised, ad libitum
- Acclimation : no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 1ºC
- Humidity : no data
-Air change : no data
- Photoperiod (hrs dark / hrs light): 12 hours/12 hours

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

3 months

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
100 ppm (males = 7.79 mg/kg bw/d, females = 10.23 mg/kg bw/d)
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
500 ppm (males =37.85 mg/kg bw/d, females = 54.20 mg/kg bw/d)
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
2500 ppm (males = 212.30 mg/kg bw/d, females =266.69 mg/kg bw/d)
Basis:
nominal in diet

No. of animals per sex per dose:

15 animals/sexe/group

Control animals:

yes, concurrent no treatment

Details on study design:

no

Positive control:

no

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: inspected daily, and a weekly record was kept of any alterations and signs occurring.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: carried out 1 and 3 months after start of study on 5 males and 5 females in each case. The urines were collected over a period of about 17 hours.

BODY WEIGHT: Yes
- Time schedule for examinations: recorded weekly.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

HAEMATOLOGY: Yes
CLINICAL CHEMISTRY: Yes
URINALYSIS: Yes

OTHER: body temperatures were taken rectally for all males and females in all the dose groups, 1 and 3 months after start of study, using a second thermometer.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

no

Statistics:

The following were calculated: arithmetic group means, standard deviations, upper and lower confidence limits on the confidence level of 1 - alpha = 95 % and 1 - alpha = 99 %. The comparison of the values of the test collective with the control collective was made by means of the significance test (U test) after Mann, Whitney and Wilcoxon, on the significance level of alpha = 5 % and alpha = 1 %. An IBM 370/145 computer was used. The random lists were produced by means of the Subprogram Randu from the Scientific Subroutine Package from IBM on the IBM 370 computer.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Description (incidence and severity):

The findings of the urinalyses after one and three months of the study period for five males and five females from each group did not reveal any differences between controls and treated rats up to the dose group of 2500 ppm

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

After 2500 ppm the thymus, heart, lung, spleen and testicle weights of the males, and the lung weights of the females were significantly lower than those of the controls due to the low body weights.

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Liver: Female animals in the control and dose groups, and males in the control and dose groups up to and including 500 ppm, occasionally exhibited slight fine-dust fat infiltrations in periphero-lobular hepatocytes.

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: In the 2500 ppm dose group, 2 males and 2 females exhibited temporary slight convulsions. The other animals behaved normally. None of the animals died.

BODY WEIGHT AND WEIGHT GAIN: Males and females in the 100 and 500 ppm study groups gained weight at about the same rate as the controls. Individual weekly means after 500 ppm which deviate significantly from the values for the controls are without toxicological importance, as the differences are very slight, and both higher (males) and lower figures (females) occurred. The dose of 2500 ppm resulted in significantly lower body weights in the males for the entire study period, and in the females for the majority of the determination dates.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): The males and females administered the active ingredient up to a dose of 2500 ppm in their feed consumed about the same amount of powdered feed as the controls.

HAEMATOLOGY: Haemoglobin content and haematocrit value were lower in comparison to the controls in dose correlation. The differences are significant (p< 0.05) after 500 (only haematocrit) and 2500 ppm. In addition the MCH and MCV values were significantly lower after 2500 ppm. In the case of the females, there were no relevant and significant variations between treated and control groups. The differential blood count figures listed indicate that the treated animals in the study groups up to 2500 ppm did not differ from the controls in percentages of various cell forms. The structures of the various cell types also did not reveal any pathological findings.

CLINICAL CHEMISTRY: Treated animals in all the study groups up to 2500 ppm did not differ significantly and in dose correlation from the controls. The activities of alkaline phosphatase (ALP), the transaminases GOT and GPT, and glutamate dehydrogenase (GLDH) did not reveal any toxicologically significant differences between treated rats in the groups up to 2500 ppm and the control animals. These study groups also did not differ significantly in bilirubin and total protein concentrations in the plasma.

ORGAN WEIGHTS: After 2500 ppm the thymus, heart, lung, spleen and testicle weights of the males, and the lung weights of the females were significantly lower than those of the controls due to the low body weights. The other organ weight differences are slight and are not distributed in a dose correlation.

GROSS PATHOLOGY: The autopsies on all the rats did not detect any indications of specific damage in the study groups up to 2500 ppm.

HISTOPATHOLOGY: NON-NEOPLASTIC: (Liver) Female animals in the control and dose groups, and males in the control and dose groups up to and including 500 ppm, occasionally exhibited slight fine-dust fat infiltrations in periphero-lobular hepatocytes. Slightly increased fine droplet lipid infiltration in individual hepatocytes was observed in animal 102 (male, 2500 ppm). Animals 103 and 105 (both males, 2500 ppm) showed signs of moderately defined centrolobular fat infiltration in the liver parenchyma cells; Oil-Red-O positive substances were present in fine to large droplet form and did not produce birefraction when examined under a polarization microscope. Animals 103 and 105 had visibly empty vacuoles in the cytoplasm of the hepatocytes. There were no histopathological findings present in any other organs.

Dose descriptor:

NOAEL

Effect level:

500 ppm

Sex:

male/female

Basis for effect level:

other: Males : 37.85 mg/kg bw/d, Females : 54.20 mg/kg bw/d. No lesions in any animals.

Dose descriptor:

LOAEL

Effect level:

2 500 ppm

Basis for effect level:

other: temporary slight convulsions, significantly lower bodyweights, haemoglobin content and haematocrit value decreased significantly, decreased of organ weights, and histopathological findings in liver (hepatocellular fat accumulation, males only).

Critical effects observed:

not specified

Conclusions:

According to this 90 days study , the NOAEL was of 500 ppm (37.85 mg/kg bw/d, males) and 54.2 mg/kg/day for the females.

Executive summary:

The repeated study was made in accordance to OECD 408 guideline and GLP requirements. Male and female rats (15 animals/sexe/dose) were exposed to 1,2,4-triazole during 90 days at 100, 500 and 2500 ppm in feed. Body weight, clinical signs, food consumption, haematology, chinical chemistry, urinalysis, body temperature and necropsy were studied and registered.

No mortality was observed during the study, no changes of the food consumption or clinical chemistry, no gross pathology, at any dose.

Effects of 1,2,4 -triazole were observed at 2500 ppm : temporary slight convulsions, significantly lower bodyweights, haemoglobin content and haematocrit value decreased significantly, decreased of organ weights, and histopathological findings in liver.

According to this study, the NOAEL was of 500 ppm (37.85 mg/kg bw/d, males ; 54.20 mg/kg bw/d, females).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

37.85 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

The key study was score as Klimish 1.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

One repeated study of 90 days was available and was made in accordance to OECD 408 guideline and GLP requirements.

Groups of 15 male and 15 female rats received 1,2,3 -triazole for three months in the following concentrations in their food : 0 (control), 100, 500 and 2500 ppm. Appearance, behaviour, growth, food consumption and mortality were unaffected in the males and females with doses up to 500 ppm. 2500 ppm produced temporarily reduced food consumptiion and lower bodyweights, and temporary slight convulsions in animals.

The blood was not damaged by 1,2,4 -triazole in the dose groups up to 500ppm. Significantly lower haemoglobin, haematocrit, MCV and MCH values in the male rats after 2500 ppm point to an effect on the blood.

Clinical chemistry, gross pathology and histopathology did not detect any liver damage in the male and female rats receiving up to 500 ppm. After 2500 ppm, slight to moderate fat accumulation in liver parenchyma cells was found in three of 15 males examined, and this is attributed to the treatment.

Urinalyses, clinical chemitry, autopsies and histopathology provided no indications of kidney damage in the dose groups up to 2500 ppm. Blood sugar and cholesterol concentrations were within the normal range in the rats up to the dose group of 2500 ppm. 1,2,4 -triazole did not affect functioning of the thyroid up to the dose of 2500 ppm.

Autopsies and histopathological examinations did not reveal any indications of treament-induced organ alterations in the groups up to 2500 ppm, with the exception of the liver findings mentioned.

Doses up to 500 ppm were therefore tolerated without any ill-effect under the conditions described. Therefore, the NOAEL was of 500 ppm (37.85 mg/kg bw/d, males ; 54.20 mg/kg bw/d, females).

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
It is the single oral repeated study available.

Repeated dose toxicity: via oral route - systemic effects (target organ) digestive: liver

Justification for classification or non-classification

Repeated oral toxicity :

1,2,4 -triazole is not classfied for this endpoint, according to the Regulation EC no.1272/2008 (CLP) and according to the EU Directive 67/548/EEC.

Justification (CLP) : There is a 90 -days repeated dose toxicity study, and the effects on liver and red blood celle parameters were observed at 2500 ppm (212 mg/kg bw/d) only. This concentration is higher to 100 mg/kg bw/d => no classification.