Ammonium nitrate

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Well documented literature. The study has been performed in line with OECD and/or EC guidelines but with a substance analogue and the data are read across.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Principles of method if other than guideline:

In this study, the chronic toxicity (52-week oral feeding) and carcinogenicity (104-week oral feeding) was investigated.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium sulphate

EC Number:

231-984-1

EC Name:

Ammonium sulphate

Cas Number:

7783-20-2

Molecular formula:

H3N.1/2H2O4S

IUPAC Name:

diammonium sulfate

Details on test material:

- Name of test material (as cited in study report): Ammonium sulfate
No further data

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Yoneyama Kagaku Kogyo (Osaka Japan)
- Age at study initiation: 5 weeks
- Housing: three or four rats per plastic cage
- Diet: ad libitum
- Water: Tap water ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 ± 1 °C
- Humidity (%): 55 ± 5 %
- Air changes (per hr): 18
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Recapture rates for ammonium sulfate from the admixed diet at each concentration level were confirmed to be 95.4-98.7%.

Duration of treatment / exposure:

52 and 104 weeks

Frequency of treatment:

continuously in the diet

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
42, 256, 1527 mg/kg bw/day (males); 48, 284, 1490 mg/kg bw/d (females
Basis:
other: actual ingested, 52-week chronic toxicity study

Doses / concentrations 2

Remarks:

Doses / Concentrations:
0.1, 0.6, 3.0% in the diet
Basis:
other: nominal in diet, 52-week chronic toxicity study

Doses / concentrations 3

Remarks:

Doses / Concentrations:
564.1, 1288.2 mg/kg bw/d (males); 649.9, 1371.4 mg/kg bw/d (females)
Basis:
other: actual ingested, 2-year carcinogenicity study

Doses / concentrations 4

Remarks:

Doses / Concentrations:
1.5, 3 % in the diet
Basis:
other: nominal in diet 2-year carcinogenicity study

No. of animals per sex per dose:

Chronic toxicity study: 10/sex
Carcinogenicity study: 50/sex

Control animals:

yes, plain diet

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: every 2 weeks until week 10 and every 5 weeks thereafter.

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

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 52 weeks
- Anaesthetic used for blood collection: Yes: ether
- Animals fasted: Yes: overnight
- How many animals: 10
- Parameters checked: red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count (Plt) and white blood cell count (WBC). Differential leukocyte counts and the reticulocyte count (Ebl).

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 52 weeks
- Animals fasted: Yes: overnight
- How many animals: 10
- Parameters checked: total protein (TP), albumin (Alb), albumin/globulin ratio (AIG), total bilirubin (T-bil), total cholesterol (T-Cho), triglyceride (TG), blood urea nitrogen (BUN), creatinine (Cre), calcium (Ca), inorganic phosphorus (IP), sodium (Na), potassium (K), chloride Cl), aspartate transaminase (AsT), alanine transaminase (AlT), alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (gamma-GTP)

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
Brain, lungs, heart, spleen, liver, adrenals, kidneys and testes were weighed. As for adrenals, kidneys and testes, weights of each side were separately recorded and the total of both sides was used for calculation of group mean and SD values.
In addition to these organs, the nasal cavity, trachea, aorta, pituitary, thyroids, parathyroids, salivary glands, tongue, esophagus, stomach, duodenum, jejunum, ileum, caecum, colon, rectum, pancreas, urinary bladder, epididymides, prostate, seminal vesicles, ovaries, uterus, vagina, mammary glands, skin, mesenteric and submandibular lymph nodes, thymus, sternum, femur including bone marrow, sciatic nerve, trigeminal nerve, spinal cord (cervical, thoracic and lumber cords), eye, Harderian gland and thigh muscle. All organs and tissues in the control and 3.0% group animals were histopathologically examined. Additionally, macroscopically abnormal sites in the 0.1% and 0.6% group animals in the chronic study and all organs and tissues of the 1.5% animals in the carcinogenicity study were also histopathologically examined.

Statistics:

Variance in data for body weights, hematology, serum biochemistry and organ weights were checked for homogeneity by Bartlett test. When the data were homogeneous, one-way analysis of variance (ANOVA) was used. In the heterogeneous cases, the Kruskal-Wallis test was applied. When statistically significant differences were indicated, Dunnett's multiple test was employed for comparison between control and treated groups. Final survival rates and the incidences of tumor and non-neoplastic lesions were compared with the Fisher's exact probability test or the Mann-Whitney's U-test.

Results and discussion

Results of examinations

Details on results:

CLINICAL SIGNS AND MORTALITY
In the chronic toxicity study, no mortality was found in any groups throughout the treatment period.
In the carcinogenicity study, the survival rate of control, 1.5% and 3.0% groups were 88%, 78% and 76%, respectively, for males, and 76%, 80% and 80%, respectively, for females, and no significant differences were observed among the groups.

BODY WEIGHT AND WEIGHT GAIN
No test substance-related change in the body weights was found.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
A tendency for increase of food intake in the male 3.0% group in the chronic toxicity study was noted.

HAEMATOLOGY
No significant variation was found.

CLINICAL CHEMISTRY
No dose related alteration was found.

ORGAN WEIGHTS
Absolute and relative kidney weights were increased or showed a tendency for increase at 3.0% in both sexes in the chronic toxicity study. Absolute spleen weights were decreased and relative liver weights were increased in the 3.0% male dose group. No dose-related changes were found in the other organs.

GROSS PATHOLOGY
There were no obvious macroscopic findings in any group in either the chronic toxicity or carcinogenicity studies, except for massive, nodular or focal lesions suggesting neoplastic change in the carcinogenicity study.

HISTOPATHOLOGY:
In the carcinogenicity study, non-neoplastic and neoplastic lesions were noted in the control and treatment groups, with no significant inter-group difference in their incidences or severity.

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

256 mg/kg bw/day (actual dose received)

Sex:

male

Basis for effect level:

other: 0.6% in the diet; Absolute and relative kidney weights were increased at the high dose level for both sexes. Absolute spleen weights were decreased and relative liver weights were increased in high dose males.

2

Dose descriptor:

NOAEL

Effect level:

284 mg/kg bw/day (actual dose received)

Sex:

female

Basis for effect level:

other: 0.6% in the diet: Absolute and relative kidney weights were increased at the high dose level for both sexes.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Organ weight of male rats fed diet containing ammonium sulfate for 52 weeks (Chronic toxicity study).

	control	0.1%	0.6%	3.0%
Body weight (g)	410.9 ± 12.3	428.6 ± 17.6	416.7 ± 23.7	400.5 ± 15.1
Brain (g)	2.04 ± 0.05	2.03 ± 0.07	2.05 ± 0.05	2.04 ± 0.05
Lungs (g)	1.20 ± 0.09	1.23 ± 0.21	1.16 ± 0.07	1.13 ± 0.06
Heart (g)	1.09 ± 0.08	1.10 ± 0.07	1.08 ± 0.05	1.08 ± 0.07
Spleen (g)	0.73 ± 0.05	0.72 ± 0.04	0.83 ± 0.36	0.68 ± 0.04 *
Liver (g)	9.62 ± 0.58	9.92 ± 0.73	10.26 ± 0.63	10.0 ± 0.85
Adrenals (g)	0.03 ± 0.01	0.04 ± 0.01	0.04 ± 0.00	0.04 ± 0.00
Kidneys (g)	2.35 ± 0.25	2.32 ± 0.11	2.42 ± 0.11	2.51 ± 0.11 *
Testes (g)	3.38 ± 0.17	3.27 ± 0.11	3.25 ± 0.25	3.29 ± 0.14

Organ weight of female rats fed diet containing ammonium sulfate for 52 weeks (Chronic toxicity study).

	control	0.1%	0.6%	3.0%
Body weight (g)	207.4 ± 13.49	220.3 ± 8.68	219.2 ± 13.62	212.7 ± 24.39
Brain (g)	1.86 ± 0.04	1.83 ± 0.04	1.83 ± 0.05	1.82 ± 0.05
Lungs (g)	0.82 ± 0.06	0.79 ± 0.10	0.83 ± 0.12	0.79 ± 0.05
Heart (g)	0.65 ± 0.05	0.67 ± 0.05	0.70 ± 0.03	0.67 ± 0.05
Spleen (g)	0.44 ± 0.04	0.44 ± 0.02	0.45 ± 0.03	0.45 ± 0.07
Liver (g)	4.44 ± 0.26	4.66 ± 0.35	4.69 ± 0.40	4.89 ± 0.42
Adrenals (g)	0.04 ± 0.00	0.04 ± 0.01	0.04 ± 0.01	0.04 ± 0.01
Kidneys (g)	1.25 ± 0.07	1.35 ± 0.08 *	1.35 ± 0.09	1.39 ± 0.08 **

* Significantly different from the control at p<0.05. **Significantly different from the control at p<0.01.

Applicant's summary and conclusion

Executive summary:

In the subchronic part of the study, groups of 10 rats/sex were fed a diet containing the test substance (purity not given) at concentrations of 0, 0.1, 0.6, or 3% for 1 year. These concentrations corresponded to average daily intakes of 0, 42, 256, and 1527 mg/kg bw/d for males and 0, 48, 284, and 1490 mg/kg bw/d for females, respectively. For investigation of the carcinogenic potential, groups of 50 rats/sex were fed a diet containing the test substance (purity not given) at concentrations of 0, 1.5, or 3% for 2 years. These concentrations corresponded to average daily intakes of 0, 564.1, and 1288.2 mg/kg bw/d for males and 0, 649.9, and 1371.4 mg/kg bw/d for females respectively.

Absolute and relative kidney weights were increased at the high dose level for both sexes. Absolute spleen weights were decreased and relative liver weights were increased in high dose males. No macroscopic changes were recorded by gross pathology, except for massive nodular or focal lesions suggesting neoplastic changes. At histopathological examination, non-neoplastic and neoplastic lesions were noted in the control and treatment groups, with no significant inter-group difference in their incidences or severity.

The authors concluded that the no observed adverse effect level of ammonium sulfate was the 0.6% diet, which is equivalent to 256 and 284 mg/kg bw/d in males and females, respectively, and the compound is noncarcinogenic under the conditions of the study.