Hydroxy(2-methylprop-2-enoato-O)zinc

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

ophthalmological and neurobehavioral examination not performed

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Zinc sulphate

EC Number:

231-793-3

EC Name:

Zinc sulphate

Cas Number:

7733-02-0

IUPAC Name:

zinc sulfate

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Zinc sulfate heptahydrate
- Substance type: Pure active substance
- Physical state: Crystal
- Analytical purity: 99.9 %

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Shizuoka Agriculture Cooperative Association for Laboratory Animals
- Age at arrival: 4 weeks
- Weight at study initiation: 120-150 g (male); 90-110 g (female)
- Fasting period before study: No data
- Housing: Animals were housed at 4/sex/cage in stainless cages with a wire-meshed bottom
- Diet: Pulverized chows M (Oriental Yeast Co.), ad libitum, mixed with test material
- Water: Ad libitum
- Acclimation period: One week

ENVIRONMENTAL CONDITIONS
- Temperature: 24±1 °C
- Humidity: 55 ± 5 %
- Air changes (per hr): No data
- Photoperiod: 10 h dark/14 h light cycle

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: Mixed with basic feed

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): No data
- Mixing appropriate amounts with (Type of food): Pulverized chows M
- Storage temperature of food: No data

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Not applicable

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

Daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 300, 3000, 30000 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

12

Control animals:

yes, plain diet

Details on study design:

The animals were divided into four groups, each of which included 12 animals of each sex and fed on diet containing Zinc sulfate heptahydrate at four different concentration levels 0, 300, 3000 and 30000 ppm, for 13 weeks.

Positive control:

None

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily


BODY WEIGHT: Yes
- Time schedule for examinations: Weekly


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Time schedule for examinations: Twice weekly
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes


WATER CONSUMPTION: Yes
- Time schedule for examinations: Twice weekly

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY AND CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: No data
- Anaesthetic used for blood collection: Yes (under light ether anaesthesia)
- Animals fasted: No data
- How many animals: Male: 12, 12, 12 and 12 animals in control, low, mid and high dose groups, respectively; Female: 11, 12, 11 and 12 animals in control, low, mid and high dose groups, respectively
- Parameters checked:
Haematology: Erythrocyte count, hemoglobin, leukocyte count and differential count of leukocyte (%)
Clinical chemistry: Total plasma protein, alkaline phosphatase, glucose, urea nitrogen, SGOT, SGPT, cholesterol and calcium.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
After necropsy at the termination of the study the following organs were weighed: Brain, pituitary, thyroid, heart, thymus, liver, kidney, spleen, adrenals, gonads (testes or ovaries), and muscles (triceps surae).

HISTOPATHOLOGY: Yes
- For histopathology following organs and tissues were collected: Brain, pituitary, thyroid, heart, thymus, liver, kidney, spleen, adrenals, gonads (testes or ovaries), and muscles (triceps surae), submaxillary glands, lungs, mesenteric lymph nodes, pancreas, stomach, small and large intestine, accessory genital organs, bone and bone marrow (sternum and femur), and lesions of gross abnormalities
- 3 or 4 µm paraffin sections from the specimens were stained with hematoxylin-eosin, periodic acid Schiff's reaction and azan for microscopic observations.

Other examinations:

None

Statistics:

Student's t-test was used to estimate the statistical differences between controls and treated groups.

Results and discussion

Results of examinations

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):

effects observed, treatment-related

Food efficiency:

effects observed, treatment-related

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

effects observed, treatment-related

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY:
- At 30000 ppm: Animals showed symptom of discarding the diet from the food jar by picking it out with their fore-limbs. This symptom began a week after commencement of the experiment and persisted throughout the study. No moribund animals of either sex were found.
- At ≤ 3000 ppm: No remarkable signs in either sex. Two females, one of the control and one of the 3000 ppm group, were killed in extremis due to suppurative pyelitis during the study.

BODY WEIGHT AND WEIGHT GAIN:
- At 30000 ppm: Depressed weight gain and dwarfism was observed in males. Weight gain of females in this group was slightly depressed during the study with significant differences to control animals in the 1st to 5th week of the study.
- At ≤ 3000 ppm: No statistically significant differences were observed when compared to control.

FOOD & WATER CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- At 30000 ppm: Food intake of males decreased after the third week of the study. A similar reduction was seen in females of this group during the 1st to 6th week but then disappeared. A slightly lower value of average food and water intake was reported only in males.
- At ≤ 3000 ppm: No statistically significant differences were observed when compared to control.

FOOD EFFICIENCY:
There were some fluctuations in food efficiency in each group.
- At 30000 ppm: Slight reduction in overall average value was shown only in males.
- At ≤ 3000 ppm: No statistically significant differences were observed when compared to control.


HAEMATOLOGY:
-At 30000 ppm: A moderate reduction in leukocyte count was shown in both sexes. Males showed a slight decrease in hematocrit and hemoglobin concentration.
- At 3000 ppm: No remarkable changes in animals but there was a slight increment of hemoglobin concentration in females.

CLINICAL CHEMISTRY:
- Significant reductions or reductive tendencies were seen in rats in the following parameters: SGOT and SGPT in all male groups, total protein, cholesterol and calcium levels in males in the 30000 ppm group and calcium level in females in both the 3000 and 30000 ppm groups.


ORGAN WEIGHTS:
-At 30000 ppm: A slight or moderate decrease in absolute and relative weights was seen in the liver and kidney among males.
- Significant fluctuations of absolute or relative organ weights were seen in various organs from chemically treated groups of both species, no clear relationship with the treatment could be shown.
- At ≤ 3000 ppm: Statistically significant changes were not observed when compared to control.

GROSS PATHOLOGY
No remarkable gross lesions were attributable to the treatment.

HISTOPATHOLOGY: NON-NEOPLASTIC
- At 30000 ppm: Pancreatic lesions as well as degeneration and necrosis of the acinar cells, clarification of centroacinar cells and interstitial fibrosis. No other lesions attributable to the treatment.
- No histopathological abnormalities were observed in the bone or male genital organs which had elsewhere been reported to have sustained toxic changes due to an overdose of Zinc.

Effect levels

Dose descriptor:

NOEL

Effect level:

3 000 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: - No remarkable clinical signs in either sex at ≤ 3000 ppm diet admix, approximately equivalent to 234 zinc sulphate mg/kg bw/day (male) and 243 zinc sulphate mg/kg bw/day (female) (equivalent to approximately 53.5 mg Zn/kg bw/day)

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

Under the test conditions, the NOEL of Zinc sulphate heptahydrate was determined to be 3000 ppm (approximately equivalent to 234 mg/kg bw/day in males or 243 mg/kg bw/day in females) in rats.

Executive summary:

In a repeated dose toxicity study conducted similarly to the OECD Guideline 408, Zinc sulphate heptahydrate was administered by oral (feed) to groups of Wistar rats (12/sex/dose) at the dose-levels of 0, 300, 3000 and 30000 ppm for 13 weeks. Examinations during the study included: mortality, clinical signs, body weight, food and water consumption, haematology, blood chemistry, gross pathology, organ weights and macroscopic examination.

 

At 30000 ppm, rats showed symptom of discarding the diet from the food jar by picking it out with their fore-limbs. This symptom began a week after commencement of the experiment and persisted throughout the study. No moribund animals of either sex were found. Depressed weight gain and dwarfism was observed at 30000 ppm in males; weight gain of females in this group was slightly depressed during the study with significant differences to control animals in the 1st to 5th week of the study. At 30000 ppm, food intake of males decreased after the third week of the study. A similar reduction was seen in females of this group during the 1st to 6th week but then disappeared. A slightly lower value of average food and water intake was reported only in males. At 30000 ppm, a moderate reduction in leukocyte count was shown in both sexes and males showed a slight decrease in hematocrit and hemoglobin concentration. Significant reductions or reductive tendencies were seen in rats in the following parameters: SGOT and SGPT in all male groups, total protein, cholesterol and calcium levels in males in the 30000 ppm group and calcium level in females in both the 3000 and 30000 ppm groups. At 30000 ppm, a slight or moderate decrease in absolute and relative weights was seen in the liver and kidney among males. Significant fluctuations of absolute or relative organ weights were seen in various organs from treated groups of both species, no clear relationship with the treatment could be shown. No remarkable gross lesions were attributable to the treatment. At 30000 ppm, pancreatic lesions as well as degeneration and necrosis of the acinar cells, clarification of centroacinar cells and interstitial fibrosis were observed. No other lesions attributable to the treatment. No histopathological abnormalities were observed in the bone or male genital organs which had elsewhere been reported to have sustained toxic changes due to an overdose of Zinc. There were no significant differences of any effects were observed at ≤ 3000 ppm when compared to control.

 

Under the test conditions, the NOEL of Zinc sulphate heptahydrate was determined to be 3000 ppm (approximately equivalent to 234 mg/kg bw/day in males or 243 mg/kg bw/day in females) in rats.