Polyphosphoric acids, ammonium salts

Endpoint summary

Description of key information

The pivotal repeated dose study was a 52 week study by the oral route with the analogous substance ammonium sulphate.  In male and female rats, dietary administration of ammonium sulphate resulted in an increase in absolute and relative kidney weights  at the high dose level for both sexes. Absolute spleen weights were decreased and relative liver weights were increased in high dose males only. The NOAEL for these effects was 0.6% in the  diet, which is equivalent to 256 and 284 mg/kg bw/d in males and females, respectively.  The study was performed to methods equivalent to OECD 453, with few deviations. The deviations noted probably arise as a result of the publication of this data in a journal format as opposed to a study report.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Remarks:

combined repeated dose and carcinogenicity

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented literature study performed according to methods comparable to an appropriate guideline. The reliability has been assigned in accordance with 'practical guide 6: How to report read-across and categories' which states that the maximum reliability for a read-across study is 2. The study is considered to be adequate and reliable for the purpose of registration under REACH (Regulation (EC) No. 1907/2006) as part of a weight of evidence approach. Read-across in accordance with Annex XI, Section 1.5 of Regulation (EC) No. 1907/2006 (REACH) is justified on the following basis: Polyphosphoric acids, ammonium salt (also known as ammonium polyphosphate) is a mixture of oligomeric species of ammonium phosphate. When analysed the substance appears to consist mainly of ammonium orthophosphates, ammonium diphosphate and ammonium triphosphate. In vivo, it is considered that soluble polyphosphates will be metabolised to the orthophosphate form. Predominantly this occurs as a result of intestinal alkaline phosphatase action. The source chemical (ammonium sulphate) and the target substance (ammonium polyphosphate) are structurally similar substances. Both are soluble inorganic salts. In vivo both substances will be (bio)transformed into their respective ionic forms; ammonium cation (NH4+) plus anion (either sulphate or phosphate). NH4+ ions are immediately transformed into urea by the liver and do not exist in the blood in relevant amounts unless in case of liver failure. Exposure to the non-common compound, the sulphate ion, will not result in toxicological effects. Similarly the effects of phosphate are not considered to be toxicologically significant and as such the ammonium ion is the key moiety for assessment of the systemic toxicity of ammonium polyphosphate. The effects of the target compound (ammonium polyphosphate) are expected to be equal to the effects of the source substance (ammonium sulphate) for the property under consideration.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Deviations:

yes

Remarks:

No opthalmological evaluation performed, clinical signs not reported in the study report, no haematology or clinical chemistry measurements made during the study.

Principles of method if other than guideline:

Male and female F344 rats were exposed to various concentrations of ammonium sulfate in the diet over a period of either 52 weeks (chronic toxicity study) or 104 weeks (carcinogenicity study).

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan (Atsugi, Japan)
- Age at study initiation: 5 weeks
- Weight at study initiation: 100-150 g
- Fasting period before study: no data
- Housing: 3 or 4 rats per cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): 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)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): test diet replaced ever 2 weeks
- Mixing appropriate amounts with (Type of food): powdered basal diet (CRF-1)
- Storage temperature of food: under refrigeration

Stability of ammonium sulphate in the solid pellet diet was evaluated and no decomposition was confirmed after storageunder refrigeration or at room temperature for 2 weeks.

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 or 104 weeks

Frequency of treatment:

Continuously (in diet)

Remarks:

Doses / Concentrations:
42, 256, 1527 mg/kg bw/day (males) 48, 284, 1490 mg/kg bw/day (females)
Basis:
other: actual ingested during 52-week chronic study. Calculated on the basis of food consumption and body weight

Remarks:

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

Remarks:

Doses / Concentrations:
564.1, 1288.2 mg/kg bw/day (males); 649.9, 1371.4 mg/kg bw/day (females)
Basis:
other: actual ingested during 104-week carcinogenicity study. Calculated on the basis of food consumption and body weight

Remarks:

Doses / Concentrations:
0, 1.5, 3%
Basis:
other: nominal in diet, 104-week carcinogenicity toxicity study

No. of animals per sex per dose:

52-week chronic toxicity study: 10 animals per sex per dose group
104-week carcinogenicity study: 50 animals per sex per dose group

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: selected on basis of a 13-week dietary study in which rats were administered diets containing 0%, 0.38%, 0.75%, 1.5% and 3.0%. Reduced bodyweight gains and diarrhea were noted in males at the 3.0% dose level. NOAEL estimated to be 866 mg/kg/day (males) and 1975 mg/kg/day (females)

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


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: No data

OPHTHALMOSCOPIC EXAMINATION: YNo data


HAEMATOLOGY: Yes
- Time schedule for collection of blood: at termination of study (52 weeks) No data from carcinogenicity study
- Anaesthetic used for blood collection: Yes (ether)
- Animals fasted: Yes
- How many animals: 10 per group
- 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: at termination of study (52 weeks) No data from carcinogenicity study
- Animals fasted: Yes
- How many animals: 10 per group
- 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.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
In the chronic toxicity study (52 weeks), no mortality was found in any groups throughout the treatment period.
In the carcinogenicity study (104 weeks), 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 changes in bodyweight were observed.

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. No effects were noted in the other test groups.

HAEMATOLOGY
No significant variation was found in the erythrocytic parameters and platelets among the groups in the chronic toxicity test. Some slight changes were found in WBC parameters but this was not significant and was not considered to be dose-dependent.

CLINICAL CHEMISTRY
No dose-related alterations were found in any of the serum biochemical parameters in the chronic toxicity study.

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: NON-NEOPLASTIC
There were no obvious macroscopic findings in any of the groups tested in the chronic toxicity or carcinogenicity studies.
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.
In the chronic toxicity study several non-neoplastic lesions were noted in the control and the 3.0% groups and there were no differences in their incidences between the groups in either sex.
Strain-related increases in some lesions were noted in all groups but there were no test substance-related increases in lesions.

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Based on 0.6% dose level. Increased absolute and relative kidney weights in the high dose group. In the high dose group a decrease in absolute spleen weights and an increase in relative liver weights were noted.

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Based on 0.6% dose level. Increased absolute and relative kidney weights in the high dose group. In the high dose group a decrease in absolute spleen weights and an increase in relative liver weights were noted.

Critical effects observed:

not specified

Table 1

Final body weight, food consumption and the amount of ammonium sulfate intake in rats fat diet containing ammonium sulfate for 52 weeks

	Dose level (%)	Final body weight (g)	Food consumption (g/rat/day)	Intakes of ammonium sulfate (mg/kg b.w./day)
Male	0	410.9 ± 12.3	13.9	-
	0.1	428.6 ± 17.6	13.6	42
	0.6	416.7 ± 23.7	13.4	256
	3.0	400.5 ± 15.1	15.7	1527
Female	0	207.4 ± 13.5	8.4	-
	0.1	220.3 ± 8.7	8.6	48
	0.6	219.2 ± 13.6	8.4	284
	3.0	212.7 ± 24.4	8.6	1490

 

Table 2

Haematology in male rats fed diet containing ammonium sulfate for 52 weeks (number of animals = 10)

	Dose level (%)
	0 (Control)	0.1	0.6	3.0
RBC 10^10/L	841.0 ± 39.3	875.0 ± 35.5	842.0 ± 22.3	868.0 ± 40.2
Hb g/dL	13.6 ± 1.0	14.3 ± 0.7	13.9 ± 0.4	14.1 ± 0.5
Ht %	43.6 ± 1.9	45.7 ± 2.0	44.1 ± 1.0	44.9 ± 2.1
MCV fL	51.8 ± 0.6	52.2 ± 0.6	52.4 ± 0.5	51.7 ± 1.0
MCH pg	16.2 ± 0.7	16.4 ± 0.3	16.5 ± 0.3	16.2 ± 0.4
MCHC g/dL	31.3 ± 1.5	31.3 ± 0.6	31.6 ± 0.5	31.3 ± 0.6
Plt 10^10/L	65.6 ± 5.7	70.3 ± 6.1	66.5 ± 4.9	65.4 ± 11.6
Ebl count/200 WBC	2.4 ± 2.0	3.9 ± 2.2	3.1 ± 1.7	2.4 ± 1.6
WBC 10^8/L	51.8 ± 16.6	44.7 ±13.5	46.1 ± 8.1	49.6 ± 13.5
Differential cell count (%)
Band	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0
Seg	36.4 ± 4.7	44.5 ± 9.0^*	43.6 ± 4.1	39.9 ± 8.2
Eosino	2.1 ± 1.3	1.9 ± 0.8	2.7 ± 2.0	1.9 ± 0.8
Baso	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0	0.1 ± 0.2
Lympho	61.1 ± 3.8	53.2 ± 9.0	53.4 ± 4.0*	57.8 ± 8.5
Mono	0.4 ± 0.7	0.4 ± 0.6	0.4 ± 0.5	0.5

Each value represents the mean ± SD

*Significantly different from the control atp< 0.05

Table 3

Haemathology in female rats fed diet containing ammonium sulfate for 52 weeks (number of animals = 10)

	Dose level (%)
	0 (Control)	0.1	0.6	3.0
RBC 10^10/L	770.0 ± 83.8	792 ± 44.3	742.0 ± 29.1	744.0 ± 40.2
Hb g/dL	13.4 ± 1.5	14.0 ± 0.8	13.0 ± 0.4	13.0 ± 1.0
Ht %	43.6 ± 4.5	44.7 ± 2.2	42.2 ± 1.5	42.3 ± 2.1
MCV fL	56.6 ± 0.3	56.5 ± 0.4	56.8 ± 0.3	56.9 ± 0.4
MCH pg	17.4 ± 0.6	17.7 ± 0.4	17.5 ± 0.6	17.5 ± 0.7
MCHC g/dL	30.7 ± 1.1	31.4 ± 0.7	30.8 ± 1.0	30.7 ± 1.3
Plt 10^10/L	61.3 ± 4.3	62.6 ± 3.7	60.0 ± 2.8	60.1 ± 5.1
Ebl count/200 WBC	7.3 ± 4.2	8.3 ± 3.0	6.5 ± 3.1	8.5 ± 3.4
WBC 10^8/L	31.1 ± 6.5	28.8 ± 3.0	24.0 ± 2.9*	28.5 ± 9.7
Differential cell count (%)
Band	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0
Seg	32.4 ± 16.6	26.3 ± 6.6	27.0 ± 3.6	26.0 ± 4.0
Eosino	1.1 ± 1.0	1.5 ± 0.9	1.8 ± 1.3	1.0 ± 0.7
Baso	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0	0.0 ± 0.0
Lympho	66.0 ± 16.4	71.5 ± 6.3	70.4 ± 4.7	72.4 ± 4.2
Mono	0.5 ± 0.5	0.7 ± 0.6	0.8 ± 0.5	0.6 ± 0.6

Each value represents the mean ± SD

*Significantly different from the control atp< 0.05

 

Table 4

Serum biochemistry in male rats diet containing ammonium sulfate for 52 weeks (number of animals=10)

 

	Dose level (%)
	0 (Control)	0.1	0.6	3.0
TP g/dL	7.3 ± 0.3	7.3 ± 0.3	7.5 ± 0.3	7.1 ± 0.3
Alb g/dL	4.8 ± 0.2	4.8 ± 0.2	4.9 ± 0.2	4.7 ± 0.3
A/G	1.9 ± 0.1	2.0 ± 0.1*	1.9 ± 0.1	2.0 ± 0.1*
T-Bil mg/dL	0.1 ± 0.1	0.2 ± 0.1	0.3 ± 0.1**	0.1 ± 0.0
T-Cho mg/dL	119 ± 12	127 ± 13	133 ± 15	115 ± 16
TG mg/dL	129 ± 28	155 ± 50	174 ± 57	123 ± 44
BUN mg/dL	18.9 ± 1.7	20.1 ± 1.6	18.4 ± 1.0	18.5 ± 1.5
Cre mg/dL	0.36 ± 0.03	0.33 ± 0.02*	0.32 ± 0.02**	0.36 ± 0.02
IP mg/dL	10.6 ± 0.2	10.8 ± 0.2	10.9 ± 0.4	10.8 ± 0.5*
IP mg/dL	5.1 ± 0.4	5.0 ± 0.5	4.5 ± 0.3**	4.9 ± 0.4
Na mEQ/L	142 ± 3	143 ± 2	143 ± 4	143 ± 5
K mEQ/L	4.3 ± 0.3	4.5 ± 20*	4.6 ± 0.3	4.4 ± 0.3
Cl mEQ/L	102 ±3	104 ± 19*	104 ± 2	102 ± 3
AsT IU/L	88 ± 4	109± 43	134 ± 45**	88 ± 21
AlT IU/L	55 ± 7	79± 1.0	97 ± 39**	57 ± 18
ALP IU/L	354 ± 75	391 ±	418 ± 46	375 ± 48
ɣ- GTP IU/L	5.0 ± 3.0	5.0 ±	7.0 ± ± 2.0	7.0 ± 2.0

Each value represents the mean ± SD

 

*Significantly different from the control atp< 0.05

**Significantly different from the control at p < 0.01

Table 5

Serum biochemistry in femalerats diet containing ammonium sulfate for 52 weeks (number of animals=10)

	Dose level (%)
	0 (Control)	0.1	0.6	3.0
TP g/dL	7.5 ± 0.3	7.7 ± 0.5	7.8 ± 0.4	7.6  ± 0.7
Alb g/dL	5.4 ± 0.3	5.5 ± 0.4	5.6 ± 0.4	5.5 ± 0.4
A/G	2.5 ± 0.2	2.6 ± 0.1	2.6 ± 0.2	2.6 ± 0.2
T-Bil mg/dL	0.2 ±0.1	0.3 ± 0.1	0.3 ± 0.2	0.4 ± 0.3
T-Cho mg/dL	123 ± 6	129 ± 8	129 ± 16	134 ± 13
TG mg/dL	84 ± 24	126 ± 36	121 ± 40	126 ± 67
BUN mg/dL	21.8 ± 6.7	1836 ± 1.2	17.1 ± 1.6*	19.1 ± 2.2
Cre mg/dL	0.36 ± 0.04	0.33 ± 0.02*	0.34 ± 0.03	0.33 ± 0.02*
IP mg/dL	10.5 ± 0.3	10.6 ± 0.4	10.7 ± 0.2	10.7 ± 0.4
IP mg/dL	4.0 ± 0.7	4.4 ± 0.5	4.3 ± 0.5	4.1 ± 0.6
Na mEQ/L	142 ± 1	144 ± 5	142 ± 1	142 ± 1
K mEQ/L	4.0 ± 0.4	4.2 ± 0.2	4.1 ± 0.2	4.0 ± 0.2
Cl mEQ/L	103 ± 3	104 ± 4	104 ± 1	101 ± 2
AsT IU/L	68 ± 7	63 ± 5	64 ± 5	64 ± 6
AlT IU/L	35 ± 6	36 ± 4	33 ± 2	33 ± 4
ALP IU/L	165 ± 35	150 ± 9	134 ± 19*	141 ± 21
ɣ- GTP IU/L	<2	<2	< 2	<2

Each value represents the mean ± SD

*Significantly different from the control atp< 0.05

 

Table 6

Organ weights of male rats fed diet containing ammonium sulfate for 52 weeks (number of animals =10)

	Dose level (%)
	0 (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
Absolute (g)
Brain	2.04 ± 0.05	2.03 ± 0.07	2.05 ± 0.05	2.04 ± 0.05
Lungs	1.20 ± 0.09	1.23 ± 0.21	1.16 ± 0.07	1.13 ± 0.06
Heart	1.09 ± 0.08	1.10 ± 0.07	1.08 0.05	1.08 ± 0.07
Spleen	0.73 ± 0.05	0.72 ± 0.04	0.83 ± 0.36	0.68 ± 0.04*
Liver	9.62 ± 0.58	9.92 ± 0.73	10.26 ± 0.63	10.0 ± 0.85
Adrenals	0.03 ± 0.01	0.04 ± 0.01	0.04 ± 0.00	0.04 ± 0.00
Kidneys	2.35 ± 0.25	2.32 ± 0.11	2.42± 0.11	2.51± 0.11*
Relative (g/100 g b.w.)
Brain	0.50 ± 0.02	0.47 ± 0.02	0.49 ± 0.04	0.51 ± 0.02
Lungs	0.29 ±0.02	0.29 ± 0.04	0.28 ± 0.02	0.28 ± 0.01
Heart	0.26 ± 0.02	0.26 ± 0.02	0.26 ± 0.02	0.27 ± 0.01
Spleen	0.18 ± 0.01	0.17 ± 0.01	0.20 ± 0.08	0.17 ± 0.01
Liver	2.34 ± 0.13	2.31 ± 0.09	2.46± 0.10	2.50 ± 0.16*
Adrenals	0.01 ± 0.00	0.01 ± 0.00	0.01 ± 0.00	0.01 ± 0.00
Kidneys	0.83 ± 0.04	0.76 ± 0.03^*	0.78 ± 0.07	0.82 ± 0.04

Each value represents the mean ± SD

*Significantly different from the control atp< 0.05

 

Table 7

Organ weight of female rats fed diet containin ammonium sulfate for 52 weeks (number of animals= 10)

	Dose level (%)
	0 (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
Absolute (g)
Brain	1.86 ± 0.04	1.83 ± 0.04	1.83 ± 0.05	1.82 ± 0.05
Lungs	0.82 ± 0.06	0.79 ± 0.10	0.83 ± 0.12	0.79 ± 0.05
Heart	0.65 ± 0.05	0.67 ± 0.05	0.70 ± 0.03	0.67 ± 0.05
Spleen	0.44 ± 0.04	0.44 ± 0.02	0.45 ± 0.03	0.45 ± 0.07
Liver	4.44 ± 0.26	4.66 ± 0.35	4.69 ± 0.40	4.89 ± 0.42
Adrenals	0.04 ± 0.00	0.04 ± 0.01	0.04 ± 0.01	0.04 ± 0.01
Kidneys	1.25 ± 0.07	1.35 ± 0.08*	1.35 ± 0.09	1.39 ± 0.08**
Relative (g/100 g b.w.)
Brain	0.90 ± 0.05	0.83 ± 0.04	0.84 ± 0.05	0.86 ± 0.09
Lungs	0.39 ±0.04	0.36 ± 0.05	0.38 ± 0.06	0.37 ± 0.04
Heart	0.31 ± 0.02	0.31 ± 0.03	0.32 ± 0.03	0.32 ±0.02
Spleen	0.21 ± 0.03	0.20 ± 0.01	0.21 ± 0.02	0.21 ±0.03
Liver	2.15 ± 0.17	2.11 ± 0.13	2.14 ± 0.18	2.31 ± 0.18
Adrenals	0.02 ± 0.00	0.02 ± 0.00	0.02 ± 0.00	0.02 ± 0.00
Kidneys	0.60 ±0.01	0.61 ±0.04	0.61 ± 0.06	0.66 ±0.05

Each value represents the mean ± SD

*Significantly different from the control atp< 0.05

**Significantly different from the control at p < 0.01

 

Table 8

 

Histopathological finding in male rats fed diet containing ammonium sulfate for 52 weeks (number of animal=10)

 

Organs	Lesions	Grade	Dose level (%)
			0 (Control)	3.0
Liver	Bile duct proliferation	+	9	8
	Necrosis, focal	++ +	1 1	2 4
Pancreas	Acinar cell atrophy focal	+	4	2
Kidney	Basophilic tubules	+	1	2
	Chronic nephropathy	+	0	1
Heart	Myocarditis, focal	+	6	6
Tongue	Mononuclear cell infiltration	+	1	0
Rectum	Erosion	+	1	0
Pituitary	Basophilic cell hyperplasia, diffuse	+	1	0
Adrenal	Pheochromocytoma, malignant		0	1
Prostate	Luminal dilatation	+	5	6
Spinal cord	Calcification	+	1	1
Adipose Tissue in abdominal cavity	Necrosis, focal	+	1	1

 

 

Table 9

Histopathological findings in female rats fed diet containing ammonium sulfate for 52weeks (number of animals=10)

Organs	Lesions	Grade	Dose level (%)
			0 (Control)	3.0
Liver	Bile duct proliferation	+	0	3
	Granuloma	+	3	2
	Altered hepatocellular foci	+	7	9
Spleen	Increased extramedullary hematopoiesis	+	1	0
Pancreas	Acinar cell atrophy, focal	+	1	0
Heart	Myocarditis, focal	+	1	2
Tongue	Mononuclear cell infiltration	+	1	2
Pituitary	Cyst	+	1	2
	Adenoma, anterior lobe		0	2
Thyroid	C-cell hyperplasia		1	0
Uterus	Endometrial stromal polyp		1	0
Harderian gland	Mononuclear cell infiltration	+	3	0

 

Conclusions:

The authors concluded that the no observed adverse effect level of ammonium sulphate 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 non-carcinogenic under the conditions of the study.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

256 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Studies on analogous substances are available to asess the repeated dose toxicity over 28 days, 90 days and 52 weeks. All studies are considered to be Klimisch reliabiltiy 2 and are presented as part of a weight of evidence in accordance with Annex XI, section 1.2 of Regulation (EC) No. 1907/2006 (REACH).

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

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

Read-across justification

Read-across from analogous substances to ammonium polyphosphate is made on the basis of common (bio) transformation products. Furthermore, the available data is presented as a weight of evidence and takes into account exposure to the ammonium ion and to the different forms of phosphate. As such this approach is considered to be robust, reliable and to present a worst-case for assessment of repeated dose toxicity and derivation of DNELs.

Individual read-across arguments for the source chemicals used is as follows:

1.   Diammonium hydrogenorthophosphate, EC number: 231-8987-8

Polyphosphoric acids, ammonium salt (also known as ammonium polyphosphate) is a mixture of oligomeric species of ammonium phosphate. When analysed the substance appears to consist mainly of ammonium orthophosphates, ammonium diphosphate and ammonium triphosphate. In vivo, it is considered that soluble polyphosphates will be metabolised to the orthophosphate form. Predominantly this occurs as a result of intestinal alkaline phosphatase action. Thus the target substance (ammonium polyphosphates) and the source substance (diammonium hydrogenorthophosphate) will be primarily absorbed as the same inorganic ions: ammonium and orthophosphate. NH4+ ions are immediately transformed into urea by the liver and do not exist in the blood in relevant amounts unless in case of liver failure.

All (bio) transformation products of the source chemical are common to the target chemicals and as such the data is considered to be adequate and reliable for use in the assessment of ammonium polyphosphate. Furthermore, the ammonium ion is considered to be the key moiety for assessment of the systemic toxicity of ammonium polyphosphate.

The effects of the target compound (ammonium polyphosphate) are expected to be equal to the effects of the source substance (diammonium hydrogenorthophosphate) for the property under consideration.

2.   Ammonium sulphate, EC number: 231-984-1

Polyphosphoric acids, ammonium salt (also known as ammonium polyphosphate) is a mixture of oligomeric species of ammonium phosphate. When analysed the substance appears to consist mainly of ammonium orthophosphates, ammonium diphosphate and ammonium triphosphate. In vivo, it is considered that soluble polyphosphates will be metabolised to the orthophosphate form. Predominantly this occurs as a result of intestinal alkaline phosphatase action.

The source chemical (ammonium sulphate) and the target substance (ammonium polyphosphate) are structurally similar substances. Both are soluble inorganic salts. In vivo both substances will be (bio)transformed into their respective ionic forms; ammonium cation (NH4+) plus anion (either sulphate or phosphate). NH4+ ions are immediately transformed into urea by the liver and do not exist in the blood in relevant amounts unless in case of liver failure.

Exposure to the non-common compound, the sulphate ion, will not result in toxicological effects. Similarly the effects of phosphate are not considered to be toxicologically significant and as such the ammonium ion is the key moiety for assessment of the systemic toxicity of ammonium polyphosphate. The effects of the target compound (ammonium polyphosphate) are expected to be equal to the effects of the source substance (ammonium sulphate) for the property under consideration.

 

3.   Tetrasodium pyrophosphate

Polyphosphoric acids, ammonium salt (also known as ammonium polyphosphate) is a mixture of oligomeric species of ammonium phosphate. When analysed the substance appears to consist mainly of ammonium orthophosphates, ammonium diphosphate and ammonium triphosphate. In vivo, it is considered that soluble polyphosphates will be metabolised to the orthophosphate form. Predominantly this occurs as a result of intestinal alkaline phosphatase action. Further, the ammonium orthophosphate will then biotransform to its constituent ions; ammonium and phosphate. NH4+ ions are immediately transformed into urea by the liver and do not exist in the blood in relevant amounts unless in case of liver failure.

The source chemical (tetrasodium pyrophosphate) and the target substance (ammonium polyphosphate) are structurally similar substances. Both are soluble inorganic phosphate salts. In vivo both substances will be (bio)transformed into their respective ionic forms; phosphate anions (either diphosphate or orthophosphate depending on degree of metabolism) and cations; either ammonium or sodium.

Exposure to the non-common compound, the sodium ion, will not result in toxicological effects at the dose levels tested. Similarly the effects of different phosphate moieties are not considered to be toxicologically significant due to in vivo (bio) transformation.

The key moiety for the assessment of ammonium polyphosphate is the ammonium cation and as such the effects of the target compound (ammonium polyphosphate) are expected to be equal to or worse than the effects of the source substance (tetrasodium pyrophosphate) for the property under consideration.

 

 

 

 

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
The study with the longest duration was chosen. The NOAEL is not the lowest but is considered to be the most appropriate study as the lowest NOAEL comes from a 28-day screening study and was 250 mg/kg bw as compared to 256 mg/kg bw .

Repeated dose toxicity: via oral route - systemic effects (target organ) cardiovascular / hematological: spleen; digestive: liver; urogenital: kidneys

Justification for classification or non-classification

 

 

Specific target organ toxicity (CLP Regulation) – repeated exposure (STOT RE)

Chronic toxicity, oral:

The effects of ammonium polyphosphate are likely to be consistent with those seen in the ammonium sulphate study presented in this dossier.

In accordance with Regulation (EC) no. 1272/2008 the criteria for classification as a specific target organ toxicant (STOT-RE) via the oral route are not met. Since effects were seen at exposure levels greater than the cut-off value for classification (100 mg/kg bw). No classification is required.