Bis(hydroxylammonium) sulphate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

CAS No. 10039-54-0:

Some informations related to reproductive organs can be derived from the data of a repeated dose toxicity study, during which Wistar rats (10 animals/sex/dose group) had been exposed to hydroxylammonium sulfate (purity > 99%) via drinking water for over 3 months at concentrations of 10, 50, and 250 ppm according to dose levels of about 0.9, 4, and 21 mg/kg bw/d . Organ weight determinations of testes at all dose levels as well as macro- and microscopic evaluations of the testes at the highest dose level (250 ppm) had been performed for the male sex, whereas with females only macro- and microscopic evaluations had been performed for the uterus and the ovary at the highest dose level (250 ppm). At the end of the study for neither of these parameters any substance related changes could be detected. It is concluded from this study that hydroxylammonium sulfate does not interfere with reproductive organ weights and morphological integrity at dose levels of up to and including 250 ppm according to a daily intake of approximately 21 mg/kg bw (NOAEL). The NOAEL for systemic adverse effects of this study was 0.9 mg/kg bw/d for both sexes based on findings of hemolytic anemia with methemoglobinemia and changes in organ weight as well as histopathological changes in spleen and liver at higher dosages (BASF AG 1992, Val. 2).

During two studies, both with limited validity, focussing on the investigation of hydroxylammonium sulfate for its tumour preventive properties in both a mouse and a rat mammary gland tumour model also the ductile development of mammary glands and the morphology of mammary glands (mouse and rat) and the morphology of the ovaries (mouse) was monitored for prolonged drinking water application of high doses of hydroxylammonium sulfate (10 mM hydroxylammonium sulfate in drinking water according to an intake of approximately 100 mg/kg bw/d for mice and 67 mg/kg bw for rats) in hydroxylammonium sulfate only treated animals. The results of these two studies show that in rodents the female sex higher dosages of hydroxylammonium sulfate may interfere with the estrus cycle and with the functional state and morphology of reproductive organs (ovaries). As evidenced by morphological signs of either atrophy or hypertrophy and secretion also the functional state and the morphological development and integrity of the mammary gland may be affected. With respect to these findings a LOAEL of 67 mg/kg bw/d can be inferred from these studies (Evarts and Brown 1977; Evarts et al. 1979; both Val. 3).

CAS No. 5470-11-1:

No valid data available concerning reproductive toxicity.

CAS No. 7803-49-8:

No valid data available concerning reproductive toxicity.

Short description of key information:
CAS No. 10039-54-0:
- 3 months, oral, rat: NOAEL P >= 21 mg/kg bw (BASF AG 1989, Val. 2)

Effects on developmental toxicity

Description of key information

CAS No. 10039-54-0:
- Oral, rat, gestation day 6-15: maternal toxicity: NOAEL = 3 mg/kg bw; embryo-/fetotoxicity: NOAEL >= 20 mg/kg bw (OECD 414), (BASF AG 1994, Val. 1)

- no developmental toxicity in rabbits expected based on WoE approach

Link to relevant study records

Reference

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27. Apr 1993 - 24. May 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study (OECD 414)

Reason / purpose for cross-reference:

other: Range-finding study

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Karl THOMAE, Biberach an der Riss, Germany
- Age at study initiation: 76 99 days
- Weight at study initiation: 248 g (average)
- Housing: singly in type DK III stainless steel wire mesh cages (floor area about 800 cm2) .
- Diet: ground Kliba 343 feed rat/mouse/hamster supplied by KLINGENTALMUEHLE AG, Switzerland, ad libitum
- Water: tap water quality from water bottles, ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24°C
- Humidity (%): 30 - 70 %
- Photoperiod: 12 hrs dark / 12 hrs light

Route of administration:

oral: gavage

Vehicle:

other: Milli-Q-water

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses of the test substance:
Analytical determinations of the purity of the test substance itself were carried out before the beginning of the study (method: potentiographic titration). The stability of the test substance was proven by reanalysis.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1-4
- Length of cohabitation: from about 16.00 hours to about 7.30 hours on the following day.
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

day 6 - 15 p.c.

Frequency of treatment:

10x by gavage

Duration of test:

20 days

Remarks:

Doses / Concentrations:
1, 3, 10, 20 mg/kg bw/d
Basis:
actual ingested

No. of animals per sex per dose:

25 (females)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
Dose selection: In a pre-study it became obvious that HAS caused clear signs of maternal toxicity at 30 and 15 mg/kg bw/day (hemolytic anemia).
Therefore, 20 mg was chosen as the upper dose.

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once a day

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: The animals were examined for clinical symptoms at least once a day, or more often when clinical signs of toxicity were elicited.

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed on days 0, 1, 3, 6, 8, 10, 13, 15, 17 and 20 p.c.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: gross pathology, weight of spleen was recorded.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Furthermore, calculations of conception rate and preand postimplantation losses were carried out.

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data

Statistics:

The DUNNETT-Test was used for a simultaneous comparison of several dose groups with the control. The hypothesis of equal means was tested. This test was performed two-sided and was used for the statistical evaluation of the following parameters: Food consumption, body weight, body weight change, corrected body weight gain (net maternal body weight change), weight of the uterus before it was opened, spleen weights (absolute and relative), number of corpora lutea, number of implantations, number of resorptions and number of live fetuses; proportion of preimplantation loss, postimplantation loss, resorptions and live fetuses in each litter; litter mean fetal body weight and litter mean placental weight.

FISHER's Exact Test was used for a pairwise comparison of each dose group with the control for the hypothesis of equal proportions. This test was performed one-sided and was used for female mortality, females pregnant at terminal sacrifice and the number of litters with fetal findings.

The WILCOXON-Test was used for a comparison of each dose group with the control for the hypothesis of equal medians. This test was performed one-sided and was used for the proportion of fetuses with malformations, variations, retardations and/or unclassified observations in each litter.

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Absolute and relative spleen weights were statistically significantly higher in the 10 and 20 mg/kg bw groups than in the control group. In the 10 mg/kg bw group the spleen weights were approx. 60% higher than the respective control values, whereas the spleen weights of the high dose group dams were nearly twice as high as in the control group. The increased spleen weights are well known substance induced effects. At the lower dose levels (1 or 3 mg/kg body weight) absolute and relative spleen weights were similar to the control weights.

At necropsy the enlargement of the spleens of all dams of test groups 10 and 20 mg/kg body weight/day is in-line with the distinct increases in absolute and relative spleen weights in these groups.

Dose descriptor:

NOAEL

Effect level:

3 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
All signs of embryo-/ fetotoxicity and substance-related teratogenicity, malformations recorded, appeared without a clear dose-response relationship, can be found in a similar frequency in the historical control data and/or the differences between the groups are without biological relevance.

Dose descriptor:

NOAEL

Effect level:

>= 20 mg/kg bw/day

Basis for effect level:

other: teratogenicity

Abnormalities:

not specified

Developmental effects observed:

not specified

In the dams an enlargement of the spleens and a dose related statistically significant increase in absolute and relative spleen weights was revealed at dosages of 10 and 20 mg/kg bw/day. No substance-related effects on dams were reported for the lower dose groups. There were no substance-related differences between the groups in conception rate, the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation losses, the number of resorptions and of viable foetuses. Mean fetal body weight of the dosed groups did not differ from that of the control. Examination of foetuses did not reveal any signs for substance related abnormalities.

 

From this study a NOAEL for maternal toxicity of 3 mg/kg bw/d and a NOAEL for embryo-/fetotoxicity of 20 mg/kg bw/d can be derived.

Reference 2

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Since the primary toxicological effect of BHAS is induction of methemoglobin and this was the only effect observed on maternal animals in a rat PNDT study, the relationship between methemoglobinemia and developmental toxicity in rabbits was analyzed in other chemicals known to be methemoglobin inducers.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
All chemicals addressed are methemoglobin inducers which partly require the presence of oxygen in order to cause an effect. Since most data available were publications and secondary sources, no details beyond those specified in the endpoint entries were available.

3. ANALOGUE APPROACH JUSTIFICATION
In a weight-of-evidence approach, the data available on BHAS was analyzed, showing that the primary toxic effect observed in any of the animal studies available is hematotoxicity with formation of methemoglobin and subsequent anemia and cyanosis, leading up to development of hemangiosarcomas in the consequence. Also in the prenatal developmental toxicity study available for rats, the primary effect observed as hematotoxicity in dams. Therefore, literature data on other methemoglobin inducers was analyzed to determine whether methemoglobin formation in pregnant rabbits can lead to developmental toxicity, thereby clarifying whether the primary toxicological effect of hydroxylamine sulfate is known to cause developmental toxicity in rabbits. The substances analyzed were assessed for their primary toxicological effect, which was methemoglobin formation in most cases as well as for their effects on development in rabbits. No other parallels were drawn between substances and only the endpoint developmental toxicity, second species was considered. For further details and more information please refer to the WoE justification document in IUCLID Chapter 13 (cross-referenced) and the read-across justification document in IUCLID Chapter 13 (cross-referenced).

4. DATA MATRIX
Please refer to WoE justification document in IUCLID Chapter 13 (cross-referenced) and the read-across justification document in IUCLID Chapter 13 (cross-referenced).

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Reason / purpose for cross-reference:

other: read-across justification

Dose descriptor:

NOAEL

Remarks on result:

not determinable

Dose descriptor:

NOAEL

Remarks on result:

not determinable

Developmental effects observed:

not specified

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Additional information

An OECD 414 guideline study is available for the assessment of the developmental toxicity potential. In this study hydroxylammonium sulfate was investigated for its prenatal toxicity in Wistar rats by the oral (gavage) route of administration. Groups of 22 - 24 pregnant rats had been treated with hydroxylammonium sulfate at dosages of 1, 3, 10, and 20 mg/kg bw on day 6 through day 15 post coitum. The test substance (purity > 98.4%) had been administered as an aqueous solution and at a standard dose volume of 5 ml/kg bw. The control group, consisting of 20 dams, was dosed with the vehicle (Milli-Q-water) only. Food consumption and body weights of the animals were recorded regularly throughout the study period. The state of health of the animals was checked each day. At sacrifice on day 20 post coitum dams were assessed by gross pathology (including weight determinations of the spleen), and numbers of corpora lutea and numbers and distributions of implantation sites were recorded. Foetuses were sexed, weighed and further investigated for any external, soft tissue and/or skeletal findings. In the dams an enlargement of the spleens and a dose related statistically significant increase in absolute and relative spleen weights was revealed at dosages of 10 and 20 mg/kg bw/d. No substance-related effects on dams were reported for the lower dose groups. There were no substance-related differences between the groups in conception rate, the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation losses, the number of resorptions and of viable foetuses. Mean fetal body weight of the dosed groups did not differ from that of the control. Examination of foetuses did not reveal any signs for substance related abnormalities. From this study a NOAEL for maternal toxicity of 3 mg/kg bw/d and a NOAEL for embryo-/fetotoxicity of >= 20 mg/kg bw/d can be derived (BASF AG 1994, Val. 1).

A weight-of-evidence approach was conducted to assess the developmental toxicity of the test substance in a second species (rabbit). Therefore, data available on the substance itself as well as on other substances showing a comparable toxicological profile was taken into consideration. Additionally, species sensitivity to methemoglobin inducers and potential impact of the data on hazard and risk assessment was addressed. For detailed information, please refer to WoE justification document in IUCLID Chapter 13.

Justification for classification or non-classification

Due to the lack of toxicity on fertility and development in definite studies there is no need for classification according to reproductive toxicity.