Ammonium sulphate

Endpoint summary

Description of key information

oral

In the subchronic part of the study from Ota et al 2006, 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 NOAEL of ammonium sulfate was 256 and 284 mg/kg bw/d in males and females, respectively, and the compound is noncarcinogenic under the conditions of the study.

Inhalation
A 14-day inhalation study on rats exposed to 300 mg/m³, the only tested dose, did not report histopathological changes in the lower respiratory tract. As the respiratory tract is the target organ for inhalation exposure, the NOEL for toxicity to the lower respiratory tract is 300 mg/m³(Pepelko, Mattox and Cohen, 1980).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

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

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

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

Dose / conc.:

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

Remarks:

males (0.1% in diet)

Dose / conc.:

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

Remarks:

males (0.6 % in diet)

Dose / conc.:

1 527 mg/kg bw/day (actual dose received)

Remarks:

males (3% in diet)

Dose / conc.:

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

Remarks:

females (0.1% in diet)

Dose / conc.:

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

Remarks:

females (0.6% in diet)

Dose / conc.:

1 490 mg/kg bw/day (actual dose received)

Remarks:

females (3% in diet)

Dose / conc.:

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

Remarks:

males (1.5% in diet)

Dose / conc.:

1 288.2 mg/kg bw/day (actual dose received)

Remarks:

males (3% in diet)

Dose / conc.:

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

Remarks:

females (1.5% in diet)

Dose / conc.:

1 371.4 mg/kg bw/day (actual dose received)

Remarks:

females (3% in diet)

No. of animals per sex per dose:

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

Control animals:

yes, plain diet

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.

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.

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

Key result

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

Critical effects observed:

not specified

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.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

256 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

similar OECD TG 453

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Only lung, trachea and bronchial lymphnodes examined histopathologically, only one dose tested.

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
young adult male rats
- Weight at study initiation: mean weights: 435 +/- 20 g (control animals), 447 +/- 17 g (test animals)
- Housing: 2 per cage in 28-cn (11-inch) square wire cages
- Diet: ad libitum
- Water: ad libitum
No further data.

ENVIRONMENTAL CONDITIONS: no data

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

other: water

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Ammonium sulfate aerosol was generated from an aqueous solution with either one or two Retec nebulizers (Retec Development Laboratory, Portland, Oregon) and dried by mixing with dry air and passing it through a heated glass tube. Two nebulizers were used at concentrations greater than 500 mg/m³. Ammonium sulfate concentration was determined by collecting the aerosol on a Gelman A- E glass fiber filter at a flow rate of 2 l/min for 15 min and weighing the filter. Accuracy of the method was periodically checked by chemical analysis of the filter sample. Particle size was evaluated gravimetrically using an Andersen multi-stage sampler (Andersen Sampler Inc., Atlanta, Georgia).
No further data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

For description of the method, see above (Details on exposure)
Result of the atmosphere analysis: Particle size averaged approximately 1-2 µm diameter at 300 mg/m³. Concentrations of ammonium sulfate during exposures were maintained within +/- 10% of the desired concentration.

Duration of treatment / exposure:

1, 3, 7, or 14 days

Frequency of treatment:

8 hours per day

Dose / conc.:

300 mg/m³ air (analytical)

No. of animals per sex per dose:

10 males per group

Control animals:

yes

Details on study design:

- Dose selection rationale:
The concentrations used were determined on basis of the results from a preliminary study with rats were exposed to the maximum attainable concentration of ammonium sulfate using the same equipment and methods, i.e. a group of 6 male rats were exposed 8 h/day for 3 consecutive days to a concentration of 1000-1200 mg/m3. No toxicological effects were noted in this pretest.

Key result

Dose descriptor:

NOAEC

Effect level:

ca. 300 mg/m³ air

Sex:

male

Basis for effect level:

other: only one concentration tested, only lung, trachea and bronchial lymphnodes examined histopathologically.

Critical effects observed:

not specified

Table 1: Arterial Blood Measurements after 1, 3, 7, 14 days exposure to 300 mg/m3 Ammoniumsulfate (N=10 for all groups). Arterial blood gases, pH, and bicarbonate of rats exposed 1, 3, 7 or 14 days are shown in Table 1. No significant differences could be detected between control and exposed rats for any of the parameters measured.

	Arterial PO2 (Torr)		Arterial PCO2 (Torr)
	control	exposed	control	exposed
days exposure
1	94 ± 4	96 ± 6	37 ± 3	36 ± 4
3	96 ± 2	91 ± 5	36 ± 2	36 ± 3
7	93 ± 3	96 ± 7	34 ± 4	33 ± 4
14	89 ± 5	94 ± 8	37 ± 4	36 ± 3
	Arterial pH		Standard Bicarbonate (MM/L)
1	7.47 ± 0.03	7.45 ± 0.04	28.6  ± 2.4	27.6  ± 4.4
3	7.46 ± 0.02	7.46 ± 0.03	26.6  ± 0.8	28.6  ± 3.1
7	7.47 ± 0.02	7.49 ± 0.04	27.4  ± 1.1	26.5 ± 1.6
14	7.47 ± 0.01	7.45 ± 0.03	27.4  ± 2.6	26.7  ±0.8

Table 2: Repeated body weight measurements, vital capacity residual volume and wet lung weights of rats exposed 14 days to 300 mg/m3 ammonium sulfate (N=for all groups). Body weights, VC, RV and wet lung weights of rats exposed 14 days to 300 mg/m³ ammonium sulfate are shown in Table 2. Again, none of these parameters were significantly affected by exposure. Histological examination of the trachea, bronchial lymph nodes and lungs revealed no changes that could be definitely attributed to exposure.

		Control	Exposed
body weight pre-exposure	(GMS)	435 ± 20	447 ± 17
body weight 1 day	(GMS)	420 ± 15	437 ± 21
body weight 3 day	(GMS)	432 ± 17	441 ± 20
body weight 7 day	(GMS)	442 ± 20	445 ± 18
body weight 14 day	(GMS)	457 ± 22	446 ± 17
vital capacity	(CC)	17.1 ± 2.0	16.6 ± 1.9
residual volume	(CC)	1.92 ± 0.26	1.75 ± 0.26
wet lung weight	(GMS)	2,12 ± 0.41	2.11 ± 0.17

The authors concluded that inhaled ammonium sulfate is relatively non-toxic except at very high concentrations. They also concluded that any concentration of sulfuric acid likely to be present in the atmosphere is probably non-toxic since the chances of neutralization to ammonium sulfate in the respiratory tract is very great.

Reference 2

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No information on particle size distribution (SD), only lung, trachea and bronchial lymphnodes examined, only one dose tested. The interval between termination of exposure and examination was long.

Principles of method if other than guideline:

Range-finding study for another subacute inhalation study (exposure for up to 14 days; see other entry in this section).

GLP compliance:

not specified

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
young adult male rats
- Housing: 2 per cage in 28-cn (11-inch) square wire cages
- Diet: ad libitum
- Water: ad libitum
No further data.

ENVIRONMENTAL CONDITIONS: no data

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

not specified

Vehicle:

other: water

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Ammonium sulfate aerosol was generated from an aqueous solution with either one or two Retec nebulizers (Retec Development Laboratory, Portland, Oregon) and dried by mixing with dry air and passing it through a heated glass tube. Two nebulizers were used at concentrations greater than 500 mg/m³. Ammonium sulfate concentration was determined by collecting the aerosol on a Gelman A- E glass fiber filter at a flow rate of 2 l/min for 15 min and weighing the filter. Accuracy of the method was periodically checked by chemical analysis of the filter sample. Particle size was evaluated gravimetrically using an Andersen multi-stage sampler (Andersen Sampler Inc., Atlanta, Georgia).
No further data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

For description of the method, see above (Details on exposure)
Result of the atmosphere analysis: Particle size averaged approximately 2-3 µm diameter at 1000-1200 mg/m³. Concentrations of ammonium sulfate during exposures were maintained within +/- 10% of the desired concentration.

Duration of treatment / exposure:

3 days

Frequency of treatment:

8 hours per day

Dose / conc.:

1 000 mg/m³ air

Remarks:

1000-1200 mg/m3 air tested

No. of animals per sex per dose:

6 males

Control animals:

not specified

Details on study design:

- Dose selection rationale:
This study was carried out to determine the concentrations for another subacute inhalation study (exposure for up to 14 days; see other entry in this section)

Key result

Dose descriptor:

NOAEC

Effect level:

1 000 - 1 200 mg/m³ air

Sex:

male

Basis for effect level:

mortality

Critical effects observed:

not specified

None of the 6 rats died during three consecutive day of exposure to 1000 -1200 mg/m³ of the test substance aerosol. No gross toxicological effects were noted.

No further data

Reference 3

Endpoint:

repeated dose toxicity: inhalation, other

Remarks:

part of a study on the effects of the test substance on benzo(a)pyrene carcinogenicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The interval between termination of exposure and examination was long

Qualifier:

no guideline available

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Species:

hamster, Syrian

Strain:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
male Syrian hamsters
- Age at study initiation: ca. 10 weeks
- Fasting during exposure: yes
- Housing: individually

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-27°C (during exposure)
- Humidity (%): 28 - 62% (during exposure)

No further data

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Remarks on MMAD:

MMAD / GSD: 0.3 µm

Details on inhalation exposure:

Animals of the test group were exposed for 6 hours each day, Monday through Friday without food or water, in individual holding cages at a negative pressure of 0.15 inches of water. Exposures lasted 15 weeks. Three sulfate samples were taken each day, and samples for particle sizing were done intermittently. Sulfate concentrations in the chamber were in the range of 200 µg/m³. This level was selected as a conservative extrapolation of known sulfate levels of major metropolitan areas.

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 322 liter stainless steel and glass exposure chambers
- System of generating particulates/aerosols: Collison nebulizer
- Temperature, humidity, pressure in air chamber: 22-27°C, 28-62% rel. humidity, Chamber pressure in the system was negative and ranged between 0.14 and 0.16 inches of water.
- Air flow rate: 1 air change per minute

TEST ATMOSPHERE
- Brief description of analytical method used:
Three sulfate samples were taken each day and were analyzed by the method of Melnicoff [Melnicoff MJ et al. (1976). An Automated Method for the Determination of Sulfate. Res Comm in Chem Path and Pharm 14:377-386.]. This is an autoanalyzer method using sodium rhodizonate to colorimetrically determine sulfate concentration.

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

15 weeks

Frequency of treatment:

5 days per week, 6 hours per day

Dose / conc.:

186.6 other: µg/m3

Remarks:

ca. 0.187 mg/m³ (analytical conc.)

Dose / conc.:

200 other: µg/m3

Remarks:

ca. 0.2 mg/m³ (nominal conc.)

No. of animals per sex per dose:

40 exposed males;
40 control males

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale: Sulfate concentrations in the chamber were in the range of 200 µg/m³. This level was selected as a conservative extrapolation of known sulfate levels of major metropolitan areas.
- Rationale for animal assignment: random

Observations and examinations performed and frequency:

no data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

The following gross observations were made at necropsy of each animal
- Presence or absence of lung cancer
- Pathologic changes in all internal organs as well as the brain, nasal structures and larynx
- Overall assessment of animal condition prior to death.

The following histologic observations were made on tissues of each animal:
a) Larynx, trachea and bronchi
- The presence or absence of cancer: if present, histopathologic types
- Condition of the epithelium: normal, atrophic, hyperplastic, anaplastic, carcinomatous, ulcerated
- Condition of mucous glands: normal, atrophic, hyperplastic
- Condition of goblet cells: normal, increased, decreased
- Presence or absence of inflammation - type
b) Iungs
- Presence or absence of cancer
- Pattern of particulate accumulation, nodes, interstitial, obliterative
- Condition of bronchial, bionchiole and alveolar epithelium: normal, ulcerated, atrophic, hyperplastic, anaplastic, carcinomatous
- Presence of inflammation: peribronchiolar, intraalveolar, interstitial - type
- Maintenance of pulmonary architecture
- Presence of emphysems or fibrosis
c) Other structures:
- Presence or absence of cancer
- Metastasis or primary
- Other pathologic changes

Statistics:

Chi square analysis (mortality, body weights, development of cancer and histologic types of cancer)

Details on results:

CLINICAL SIGNS AND MORTALITY
Cumulative mortality was not significantly different between treated and control group.

BODY WEIGHT AND WEIGHT GAIN
Ammonium sulfate exposure did not have any effect on body weight when compared with the unexposed control group.

HISTOPATHOLOGY: NON-NEOPLASTIC
Inhaled ammonium sulfate did not increase the incidence or severity of pneumonitis or pulmonary fibrosis in the hamster. This inhalation did increase the incidence of emphysema as examined microscopically but not the severity. The increase in emphysema incidence was not statistically significant (9.0 vs 15.2%, EPA 1978). Another publication of this study described an increase in emphysema incidence, which is however of doubtful statistical significance. It was based on only 80 animals per group (8.6 vs 16.1%, Godleski, 1984).

HISTOPATHOLOGY: NEOPLASTIC
Ammonium sulfate inhalation hat no statistically significantly effect on the development of cancer.

Key result

Dose descriptor:

LOAEC

Effect level:

0.2 mg/m³ air (nominal)

Sex:

male

Basis for effect level:

other: This inhalation did increase the incidence of emphysema as examined microscopically but not the severity

Critical effects observed:

not specified

Incidence of all cancer and respiratory cancer

treatment	Cancer	Respiratory
control	5.9%	1.4%
ammonium sulfate	4.0%	2.9%

Location of respiratory tract cancers

treatment	Nasal	Trachea	Lung
Control	0	0	100*
Sulfate	0	50.0	50.0

Histologic types of cancer in each treatment group

Treatment	squamous	adenocarcinoma	undifferentiated	lymphoma	other
control	0	0	25.0*	75 .0	0
sulfate	50.0	0	25.0	25.0	0

Percentage of animals with benign proliferation and percentage of animals with respiratory benign proliferation

treatment	Total percentage present	Total percentage  Respiratory
control	25.4	19.4
sulfate	32.3	22.2

Percentage of animals with other significant pulmonary diseases

Treatment	Pneumonia	Emphysema	Fibrosis	other
control	25.3	9.0	1.5	1.5
sulfate	25.2	15.2	3.0	4.0

Percentage of animals with non-pulmonary significant diseases

treatment	Percentage
control	38.8
sulfate	36.4

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

300 mg/m³

Study duration:

subacute

Species:

rat

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

Oral

Fischer 344 rats (10 rats/sex/dose) were exposed during 13 weeks to diets containing 0, 0.38, 0.75, 1.5 or 3 % ammonium sulfate (corresponding to 0, 222, 441, 886, 1792 mg/kg bw/day in males and to 0, 239, 484, 961, 1975 mg/kg bw/day in females). No substance-related changes between the treatment groups and controls were found in body weights, haematology and serum parameters, or in the histological examinations (brain, heart, lung, liver, kidney, adrenal gland, spleen, testes, thymus). Relative and absolute kidney weights were increased in both male and female animals in the highest dose group. The authors did not judge this as adverse, because there were no histopathologic effects seen in the kidneys. The relative testes weight was significantly increased at all doses, but no histological effects were found. Male animals of the highest dose group exhibited diarrhea during the administration period. According to the authors the NOAEL (male) was 886 mg/kg bw/day and the NOAEL (female) was 1975 mg/kg bw/day (Takagi et al., 1999). The main limitation of the study is the low number of organs examined histopathologically compared to a standard 13-week guideline study.

A chronic oral toxicity and carcinogenicity study was conducted in rats, similar to the requirements of OECD TG 453. 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, 248, 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, 465.1, 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. There was no evidence of a long-term carcinogenic activity of the test substance. (Ota et al., 2006)

 

Dermal

There were no dermal studies available.

 

Inhalation

The repeated dose toxicity after inhalation of ammonium sulfate aerosols was studied in rats and hamsters, using non-standard protocols.

In a 14-day inhalation study, 10 male rats were exposed to an ammonium sulfate aerosol for 8 hours/day at a concentration of 300 mg/m³ (count mean particle diameter: 1 - 2 µm). The concentration used was determined on the basis of a preliminary study with rats, which were exposed for 3 consecutive days to the maximum attainable concentration of ammonium sulfate (1000 - 1200 mg/m³; 8 hours/day; count mean particle diameter: 2 - 3 µm). No adverse effects were noted in this pre-test. In the main study, arterial blood gases were measured after 1, 3, 7, and 14 days. Pulmonary function tests were performed after 14 days of exposure and histological examinations were performed at the end of the exposure period. The exposure did not result in any significant changes in lung morphology, lung volumes, and arterial blood gases. The histological examinations did not reveal any changes in the trachea, bronchial lymph nodes, and lungs and the exposure had no adverse effects on body weight. A NOEC of 300 mg/m³ for toxicity to the lower respiratory tract can be deduced from the study (Pepelko et al., 1980).

In an inhalation study consisting of two separate experiments with 160 male hamsters, in the ammonium sulfate group and control group, resp, the incidence or severity of pneumonitis or pulmonary fibrosis was not significantly increased after 15 weeks of exposure (6 hours/day, 5 days/week) to approximately 0.2 mg ammonium sulfate/m³. The animals were examined after 2 years. Also, no significant pathological changes of organs were observed. This inhalation did increase the incidence of emphysema as examined microscopically but not the severity. The increase in emphysema incidence was not statistically significant (9.0 vs 15.2 %; EPA, 1978). Another publication of this study described an increase in emphysema incidence, which is however of doubtful statistical significance. It was based on only 80 animals per group (8.6 vs 16.1 %; Godleski et al., 1984). Due to the higher number of animals used, the EPA results are more reliable and 0.2 mg ammonium sulfate/m³ cannot be regarded as a LOAEL. However it seems not acceptable to take 0.2 mg/m³ as the NOAEL from this study because the animals were not examined immediately after exposure but only after 2 years.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Classification concerning repeated oral and repeated inhalation toxicity is not warranted under Regulation (EC) No 1272/2008, as amended for the ninth time in Regulation (EU) No 2016/1179.