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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Subacute Toxicity Studies with Zinc Sulfate in Mice and Rats
Author:
Maita K, Hirano M, Mitsumori K, Takashi K and Shirasu Y
Year:
1981
Bibliographic source:
J. Pesticide Sci. 6:327-336

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: Zinc sulphate 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 study initiation: Four wk
- Weight at study initiation: 25-30 g (male); 20-25 g (female)
- Fasting period before study: No data
- Housing: Four animals housed in each stainless cage with a wire-meshed bottom
- Diet: Pulverized chows F (Oriental Yeast Co.), ad libitum, mixed with test material
- Water: Ad libitum
- Acclimation period: One wk


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:
PREPARATION OF DOSING DIET:

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


Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
No data
Duration of treatment / exposure:
13 wk
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 sulphate at four different concentration levels 0, 300, 3,000 and 30,000 ppm, for 13 wk.
Positive control:
No

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):
- 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 a week


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: 48
- Parameters checked: Erythrocyte count, hemoglobin, leukocyte count, differential count of leukocyte


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: 48
- 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 30,000 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

BODY WEIGHT AND WEIGHT GAIN:
- At 30,000 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 30,000 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:
Markedly lower than those of the control group during the first week of the study, corresponding to the decrease in food intake.
-At 30,000 ppm: The overall average food efficiency was much lower than the control group.
- At 3,000 ppm: No data

WATER CONSUMPTION:
-At 30,000 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 30,000 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 3,000 ppm group.

CLINICAL CHEMISTRY:
-At 30,000 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 3,000 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 30,000 ppm: Coincidental increase in absolute and relative weight was found in the thyroids of males and the kidneys of females
- At ≤ 3,000 ppm: Statistically not significant values when compared to control


GROSS PATHOLOGY
-At 30,000 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 30,000 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

open allclose all
Dose descriptor:
NOEL
Effect level:
3 000 ppm
Sex:
male/female
Basis for effect level:
other: No remarkable clinical signs in either sex At 3000 ppm diet admix approximately equivalent to 458 mg/kg/day (mice) and 479 mg/kg/day (female) ( equivalent to approximately 104 mg Zn/kg bw)
Dose descriptor:
LOEL
Effect level:
30 000 ppm
Sex:
male/female
Basis for effect level:
other: see 'Remark'

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

See the attached pdf for the following figure and tables:

Fig. 1. Group mean body weights in mice

Table 1. Food, chemical, water intake and food efficiency in mice

Table 3. Hematology-mean values in mice

Table 5. Blood biochemistry-mean values in mice

Table 7. Absolute and relative organ weights in mice

Applicant's summary and conclusion

Conclusions:
Under the test conditions, the NOEL of the test material in mice was determined to be 3,000 ppm (approximately equivalent to 458 mg/kg/day in male mice or 479 mg/kg/day in female mice).
Executive summary:

A study was conducted to evaluate the sub chronic (13 wk) toxicity of the test material in ICR mice. The study followed was equivalent or similar to OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents).

Mice of both sexes were fed a diet containing test substance at 0, 300, 3000 and 30000 ppm for 13 wk. The clinical signs of the animals, body weight, food, chemical and water intake, food efficiency, hematological, biochemical examination, necropsy and organ weight and histopathological examination were performed.

Animals in the 30,000 ppm group showed retarded growth along with low food intake, abnormal values in a few hematological parameters, decreased water intake and significant deviations in biochemical parameters. 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.

Under the test conditions, NOEL of the test material in mice was determined to be 3,000 ppm (approximately equivalent to 458 mg/kg/day in male mice or 479 mg/kg/day in female mice.