Sodium hydrogensulphide

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

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

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Well-documented publication. However, the study design does not meet important criteria of today standard methods.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

other:

Title:

Effects of copper sulfate, copper sulfide and sodium sulfide on performance and copper stores of pigs.

Author:

Cromwell, G.L.

Year:

1979

Bibliographic source:

J. Animal Sci. 46, 692-698

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Yorkshire pigs were treated with 225 or 450 ppm sodium sulfide in the diet for 104 days in a feeding study. The diets were prepared with three levels of Cu (0, 125 and 250 ppm) as CuSO4 in combination with three levels of Na2S (0, 225 or 450 ppm).

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Disodium sulphide

EC Number:

215-211-5

EC Name:

Disodium sulphide

Cas Number:

1313-82-2

Molecular formula:

Na2S

IUPAC Name:

disodium sulfide

Details on test material:

- Name of test material (as cited in study report): sodium sulfide

Test animals

Species:

pig

Strain:

other: Yorkshire

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 55.5 days old
- Weight at study initiation: 15.7 kg (average weight)

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: feed

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

104 days

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
225 ppm
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
450 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

144 animals (total); 4 replicates of 4 per pen

Control animals:

yes

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes

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: No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

FOOD EFFICIENCY: yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Parameters checked: haemoglobin, hematocrit

CLINICAL CHEMISTRY: No data

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

not specified

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

no effects observed

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Details on results:

BODY WEIGHT AND WEIGHT GAIN
Addition of sulfide did not affect rate or efficiency of weight gains.

FOOD EFFICIENCY
Addition of sulfide did not affect food efficiency.

HAEMATOLOGY
Haemoglobin and hematocrit values were not influenced by the levels of dietary sulfide.

Effect levels

Dose descriptor:

NOAEL

Basis for effect level:

other: see 'Remark'

Remarks on result:

not determinable

Remarks:

no NOAEL identified

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Addition of sulfide did not affect rate or efficiency of weight gains and food efficiency, and haemoglobin and hematocrit values were not influenced by the level of dietary sulfide.

Executive summary:

Read-across from Na2S to NaHS:

Given that sodium sulfide and sodium hydrogensulfide dissociate in aqueous media, it can safely be assumed that under most physiologically relevant conditions ( i.e., neutral pH) sulfide and hydrogen sulfide anions are present at almost equimolar concentrations, thus facilitating unrestricted read-across between both species. Only under extreme conditions such as gastric juice (pH << 2), sulfides will be present predominantly in the form of the non-dissociated hydrogen sulfide. In turn,hydrogen sulfide (H₂S) may be formed from both soluble sulfides, according to the following equilibria:

                           Na₂S + H₂O   →  NaOH + NaHS (2Na⁺/ OH^-/ HS^-)

                           NaHS + H₂O  →  NaOH + H₂S (Na⁺/ OH^-/ H₂S)

Similarly, hydrogen sulfide dissociates in aqueous solution to form two dissociation states involving the hydrogen sulfide anion and the sulfide anion, according to the following equilibrium:

                           H₂S  ↔  H⁺  +  HS^-  ↔  2 H⁺  +  S^2-

In conclusion, under physiological conditions, inorganic sulfides or hydrogensulfides as well as H2S will dissociate to the respective species relevant to the pH of the physiological medium, irrespective the nature of the “sulfide”, which is why read-across between these substances and H2S is considered to be feasible without any restrictions.