Ammonium iron bis(sulphate)

Endpoint summary

Description of key information

In aqueous solution ammonium iron bis(sulphate) dissociates forming sulfate, ammonium and ferric ions. The skin sensitization of this substance can therefore be assessed by evaluating the sensitization of substances forming the same ions upon dissolution. The skin sensitizing potential of Iron(II) Sulfate and Ammonium chloride was tested by local lymph node assay (LLNA) in female rats and Buehler Test, respectively. The results showed that both substances did not induce sensitization. Since GHS criteria for skin sensitization are not met ammonium iron(III) sulfate is not classified.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

This animal test determines the sensitization potential of a chemical by assessment of proliferative responses in lymph nodes draining the site of chemical application. Following exposure to metal salts lymph node cell (LNC) proliferative activity was assessed via determining the incorporation of [methyl-3H]thymidine by scintillation counting.

GLP compliance:

not specified

Type of study:

other: Local Lymph Node Assay in F344 rats

Specific details on test material used for the study:

Solutions of Iron(II) Sulfate in DMSO: Water (4:1)

Species:

other: rat

Strain:

other: F344

Sex:

female

Details on test animals and environmental conditions:

Female F344 rats, 6-8 weeks old

Vehicle:

other: DMSO: water (4:1)

Concentration:

c(FeSO4) / (w/v%): 0.0, 0.5, 1.0, 2.5, 5.0

No. of animals per dose:

3

Details on study design:

Three animals (n = 3) were used per group. Rats received 100 µl of each concentration of the test chemical on the dorsum of both ears daily for 3 consecutive days. Control rats received an equal volume of vehicle alone. Animals were sacrificed 24 h following the final exposure. The draining auricular lymph nodes were excised and pooled and weighed for each experimental group. A single suspension of lymph node cells (LNC) was prepared. Cell suspensions (1×106 cells/200 µl) were seeded into 96-well tissue culture plate (5 wells per group) and cultured at 37°C in a humidified atmosphere of 5% CO2 in air with 0.5 µCi [methyl-3H]thymidine (3HTdR). After 18 h culture, LNC were harvested with an automatic cell harvester and 3HTdR incorporation was determined by liquid scintillation counting. A stimulation index (SI), the increase in 3HTdR incorporation relative to vehicle-treated controls, was derived for each experimental group. With the same method, skin sensitization potential of potassium dichromate and cobalt chloride was tested.

Parameter:

SI

Value:

1.28

Test group / Remarks:

c(FeSO4) = 0.5%

Parameter:

SI

Value:

0.61

Test group / Remarks:

c(FeSO4) = 1.0%

Parameter:

SI

Value:

1.64

Test group / Remarks:

c(FeSO4) = 2.5%

Parameter:

SI

Value:

1.12

Test group / Remarks:

c(FeSO4) = 5.0%

Cellular proliferation data / Observations:

Exposure to FeSO4 failed to induce significant lymph node responses at all concentrations (see table 1). In comparable tests, exposure to potassium dichromate (K2Cr2O7) and cobalt chloride (CoCl2) induced strong proliferative responses.

Table 1: The draining LNC proliferative activity in the rat following exposure to iron sulfate.

LNC: lymph node cells; mean cpm: mean counts/minute ,values from five culture wells.

c(FeSO4) / (w/v%)	LNC proliferation 3HTdR incorporation / mean cpm x 10 ^-3	standard deviation / cpm x 10 ^-3	stimulation index
0.0	2.35	0.18	-
0.5	3.02	0.32	1.28
1.0	1.42	0.16	0.61
2.5	3.87	0.23	1.64
5.0	2.63	0.17	1.12

Interpretation of results:

GHS criteria not met

Conclusions:

Exposure to FeSO4 failed to induce significant lymph node responses at all concentrations investigated. In comparable tests, exposure to potassium dichromate (K2Cr2O7) and cobalt chloride (CoCl2) induced strong proliferative response. Since GHS criteria for skin sensitization are not met, iron(II) sulfate is not classified.

Executive summary:

The skin sensitizing potential of Iron(II) Sulfate was tested by local lymph node assay (LLNA) in female rats. Following exposure to solutions of the metal salt (concentration: 0% to 5%), the lymph node cell proliferative response was assessed by measuring the incorporation of [methyl-3H]thymidine. According to this article by Ikarashi et al. (published in 1992), exposure to FeSO4 failed to induce significant lymph node responses at all concentrations investigated.  In comparable tests, exposure to potassium dichromate (K2Cr2O7) and cobalt chloride (CoCl2) induced strong proliferative responses. Since GHS criteria for skin sensitization are not met, iron(II) sulfate is not classified.

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 1987-03-16 to 1987-04-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 81-6 (Skin Sensitisation)

Version / remarks:

EPA Pesticide Assessment GuidelinesSubdivision FHazard Evaluation: Human and Domestic AnimalsSeries 81: Acute Toxicity and Irritation Studies§ 81-6 "Dermal Sensitization Study"EPA 540/9-82-025, November 1982, revised at November 1984

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

This existing study was considered to be sufficient for assessing the sensitization potential of the substance to be registered. Additional animal testings of the substance are not considered necessary by the applicant.

Specific details on test material used for the study:

Name: Hoe 092297 - Substanz technischCode: Hoe 092297 OG ZC99 0001Appearance: white, crystallinePurity: 99,1 %Sample received at: 25.02.87Storage: at ca. 4°C, in a Refrigerator

Species:

guinea pig

Strain:

other: Pirbright-White

Sex:

female

Details on test animals and environmental conditions:

Strain: Hoe: DHPK (SPFLac)Origin: Hoechst AG, Kastengrund, SPF - ZuchtBody weight at start: average 240 g (= 100 %)minimum 209 g (- 13 %)maximum 263 g (+ 10 %)Number of animals: 30 (test animals and control animals) Age at start: ca. 8 WochenRandomization: 939/87Keeping of animals: groups of 5 animals per cage (material: Makrolon, Typ4)on softwood bedding Temperature: 22 + 3°CHumidity: 50 + 20 %Duration of lighting: 12 h per dayAcclimatization: at least 5 daysFeeding: ERKA-Mischfutter Nr. 8300, ad libitumWater: tap water in plastic bottles, ad libitumIdentification of the animals: marks on the coat with KMnO4, numbered cages

Route:

intradermal

Vehicle:

other: Freud's adjuvant, isotonic saline

Concentration / amount:

Test group:spot 1: 2x 0.1 ml 50 % Freud's adjuvantspot 2: 2x 0.1 ml 5 % test material in salinespot 3: 2x 0.1 ml 5 % testmaterial in 50 % Freud's adjuvantControl group:spot 1: 2x 0.1 ml 50 % Freud's adjuvantspot 2: 2x 0.1 ml salinespot 3: 2x 0.1 ml 50 % Freud's adjuvant

Day(s)/duration:

animals were monitored for 7 days

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, occlusive

Vehicle:

other: isotonic saline

Concentration / amount:

test group: 0.5 ml 25% test material in salinecontrol group: 0.5 ml saline

Day(s)/duration:

2 days occlusive conditions; subsequently, animals were monitored for 10 days

Adequacy of induction:

highest technically applicable concentration used

Route:

epicutaneous, occlusive

Vehicle:

other: isotonic saline

Concentration / amount:

0.5 ml 5 % test material in saline

Day(s)/duration:

1 day under occlusive conditions, skin reactions were assessed during the following 2 days

Adequacy of challenge:

not specified

No. of animals per dose:

Test group: 20 animalscontrol group: 10 animals

Details on study design:

Day 1: - intradermal induction, injection of different preparations at 3 spots within an 2x4 cm area on the back of the animals- Weighting of the animalsDay 1-7: area of application is monitoredDay 9: epicutaneous induction (occlusive conditions), application of the test solution on a patch (2x4 cm), covering the injection spots of the intradermal inductionDay 11: removal of the occlusive dressing and assessment of skin irritation Day 12-21: monitoring of the animalsDay 22: dermal challenge (occlusive conditions), application of the test solution on a patch (2x2 cm) on the left flank of the animalsDay 23: removal of the occlusive dressingDay 24: Assessment of skin reactionsDay 25: - assessment of skin reactions- Weighting of the animals

Positive control substance(s):

no

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5 %

No. with + reactions:

2

Total no. in group:

20

Clinical observations:

Erythema and weak edema after injection of Freud’s adjuvant with and without test material. Very weak to weak edema after application of test material in saline. Formation of scab in all groups. Weight development was not affected by the treatment.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5 %

No. with + reactions:

2

Total no. in group:

20

Clinical observations:

Erythema and weak edema after injection of Freud’s adjuvant with and without test material. Very weak to weak edema after application of test material in saline. Formation of scab in all groups. Weight development was not affected by the treatment.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Erythema and weak edema after injection of Freud’s adjuvant. Formation of scab in all groups. Weight development was not affected by the treatment.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Erythema and weak edema after injection of Freud’s adjuvant. Formation of scab in all groups. Weight development was not affected by the treatment.

Interpretation of results:

GHS criteria not met

Conclusions:

Ammonium chloride was not sensitizing in this maximization test.

Executive summary:

In this study by Hoechst AG the skin sensitizing potential of ammonium chloride was examined by an guinea pig maximization test. The test material was applied after intradermal and epicutaneous induction under occlusive conditions for 24 h. 10 % of the test group showed very weak erythema 24 and 48 h after application. All other animals (test group and control group) showed no treatment related reactions. Since the classification criteria were not met, ammonium chloride was not classified.   

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Justification for classification or non-classification

The GHS criteria for skin sensitization is not met and ammonium iron(III) sulfate is not classified.