Zinc methacrylate

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:

reference to same study

Cross-reference 2

Reason / purpose:

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:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity 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

Reference

Name:

Unnamed

Type:

Constituent

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:

mouse

Strain:

ICR

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Shizuoka Agriculture Cooperative Association for Laboratory Animals
- Age at arrival: 4 weeks
- 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 MF (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 MF
- 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: 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, 10, 11 and 8 animals in control, low, mid and high dose groups, respectively; Female: 12, 12, 12 and 11 animals in control, low, mid and high dose groups, respectively
- Parameters checked: Erythrocyte count, hemoglobin, leukocyte count and differential count of leukocyte (%)


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: Male: 12, 10, 10 and 8 animals in control, low, mid and high dose groups, respectively; Female: 11, 12, 12 and 10 animals in control, low, mid and high dose groups, respectively
- Parameters checked: 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, mesentery 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: Depressed spontaneous motility before death or sacrifice. Four males and one female in this group were found dead or killed in extremis during the study. Histological findings of these animals revealed impairment of the urinary tract and regressive changes in the exocrine gland of the pancreas. Mortality was 33.3 % in males and 8.3 % in females.
- At ≤ 3000 ppm: No treatment related toxic signs

BODY WEIGHT AND WEIGHT GAIN:
- At 30000 ppm: A more prominently retarded growth resulting in smaller body size than those of other groups.
- At 300 ppm: A significant but very slight depression of weight gain was seen in females for a week after commencement, followed by a rapid recovery to the control level.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- At 30000 ppm: The food intake of male and female mice was depressed during the first week of the study in comparison to that of the controls but showed a tendency to recover afterwards. Average food intake of these animals then remained at only a slightly lower level than that of the control group.

FOOD EFFICIENCY:
- Food efficiencies were markedly lower than those of the control group during the first week of the study, corresponding to the decrease in food intake.
- At 30000 ppm: The overall average food efficiency was much lower than the control group.

WATER CONSUMPTION:
-At 30000 ppm: Decreased in both sexes during the first week. Though males soon recovered, females showed persistent lower intake during the study.


HAEMATOLOGY:
- Male and female mice in the 30000 ppm group showed moderately lower values in hematocrit and hemoglobin concentration than those of the control group; the leukocyte count in males also decreased moderately. Morphological changes of erythrocyte anisocytosis, polychromatophilia and poikilocytosis, were seen in six males and four females which were reported by necropsy or microscopic observation to have fore-stomach ulcers. Though some significant fluctuations were seen in hematocrit, no dose dependent abnormalities were found in hemoglobin concentration and erythrocyte count in males or females at less than 3000 ppm group.

CLINICAL CHEMISTRY:
-At 30000 ppm: A slight to moderate decrease in total protein, glucose and cholesterol and a moderate to marked increase in alkaline phosphatase and urea nitrogen. Additional significant changes occurring in these animals were depression of SGPT level and increase in calcium level in females, and an increase of SGOT level in males.
- At 3000 ppm: Some fluctuations with significant differences from controls were seen in several parameters but these were all within the acceptable historical limits of mice of this strain and age.


ORGAN WEIGHTS:
-At 30000 ppm: Coincidental increase in absolute and relative weight was found in the thyroids of males and the kidneys of females
- At ≤ 3000 ppm: Statistically not significant values when compared to control.


GROSS PATHOLOGY
-At 30000 ppm: Marked emaciation, ischemic discoloration of the kidney and thyroid, atrophy of the pancreas, edematous thickening of the upper small intestine and slight splenomegaly were recorded in addition to several cases of fore stomach ulcer.


HISTOPATHOLOGY: NON-NEOPLASTIC
-At 30000 ppm: There were lesions attributable to the treatment in the pancreas, upper intestine, stomach, spleen and kidney. The pancreatic acinar cells had swollen nuclei with an increased number of clarified nucleoli and whirl-like profiles in their cytoplasm which were more basophilically stained than the controls. Single cell necrosis of the acinar cells was also a common feature in these animals. Moreover, a decrease in the number of acinus and ductule like metaplasia of acinar cells was demonstrated. There was mucosal catarrh in the upper intestine with proliferation of epithelial cells and edema at lamina propria, slight to moderate ulcerative lesions in the boundary of the fore-stomach and proliferation of erythropoietic immature cells in the splenic red pulp of these animals. Regressive changes of the renal cortex were observed in the females.
- At ≤ 3,000 ppm: Statistically not significant values when compared to control.

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 458 zinc sulphate mg/kg bw/day (male) and 479 zinc sulphate mg/kg bw/day (female) (equivalent to approximately 104 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 458 mg/kg bw/day in males or 479 mg/kg bw/day in females) in mice.

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 ICR mice (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, depressed spontaneous motility before death or sacrifice. Four males and one female in this group were found dead or killed in extremis during the study. Histological findings of these animals revealed impairment of the urinary tract and regressive changes in the exocrine gland of the pancreas. Mortality was 33.3 % in males and 8.3 % in females. At ≤ 3,000 ppm, no treatment related toxic signs were noticed. At 30000 ppm, a more prominently retarded growth resulting in smaller body size than those of other groups. At 300 ppm, a significant but very slight depression of weight gain was seen in females for a week after commencement, followed by a rapid recovery to the control level. The food intake of male and female mice was depressed during the first week of the study in comparison to that of the controls but showed a tendency to recover afterwards at 30000 ppm. Average food intake of these animals then remained at only a slightly lower level than that of the control group. The overall average food efficiency was much lower than the control group at 30000 ppm. Water consumption was decreased in both sexes during the first week at 30000 ppm; though males soon recovered, females showed persistent lower intake during the study. Male and female mice in the 30000 ppm group showed moderately lower values in hematocrit and hemoglobin concentration than control group; the leukocyte count in males also decreased moderately. Morphological changes of erythrocyte anisocytosis, polychromatophilia and poikilocytosis, were seen in six males and four females which were reported by necropsy or microscopic observation to have fore-stomach ulcers. Though some significant fluctuations were seen in hematocrit, no dose dependent abnormalities were found in hemoglobin concentration and erythrocyte count in males or females at less than 3000 ppm group. A slight to moderate decrease in total protein, glucose and cholesterol and a moderate to marked increase in alkaline phosphatase and urea nitrogen were observed at 30000 ppm. Additional significant changes occurring in these animals were depression of SGPT level and increase in calcium level in females, and an increase of SGOT level in males. At 3000 ppm, some fluctuations with significant differences from controls were seen in several parameters but these were all within the acceptable historical limits of mice of this strain and age. Coincidental increase in absolute and relative weight was found in the thyroids of males and the kidneys of females at 30000 ppm. At 30000 ppm, marked emaciation, ischemic discoloration of the kidney and thyroid, atrophy of the pancreas, edematous thickening of the upper small intestine and slight splenomegaly were recorded in addition to several cases of fore stomach ulcer. Histopathological lesions included catarrh at the upper intestine, ulcers at the boundary of fore- and glandular stomach, proliferation of erythropoietic immature cells in the splenic red pulp as well as pancreatic lesions were observed at 30000 ppm.

 

Under the test conditions, the NOEL of Zinc sulfate heptahydrate was determined to be 3000 ppm (approximately equivalent to 458 mg/kg bw/day in males or 479 mg/kg bw/day in females) in mice.