Sulphuric acid, compound with graphite

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

No additional information available.

Additional information

Short description of key information:
Sulphuric acid, compound with graphite is an inorganic solid, consisting of natural graphite and variable amounts of intercalated sulphuric acid. Graphite is a naturally occurring solid substance which is insoluble in water. Due to its physico-chemical properties it is not systemically and biologically available and does not cross biological membranes. In the aquatic compartment it can be considered as an inert substance.
The intercalated sulphuric acid is partially leached out by water and dissociated into the biologically ubiquitous sulphate and hydronium ions. Due to their ionic character, they do not cross biological membranes. Sulphate is a normal biological constituent of the body, a normal biological metabolite and a degradation product of sulphur-containing amino-acids.

Due to its physico-chemical characteristics sulphuric acid, compound with graphite is not bioavailable and does not cross biological membranes. The substance does not enter the blood stream and cannot cross the placental, blood-brain or blood-testes barriers or be secreted in milk. As a consequence, sulphuric acid, compound with graphite cannot reach relevant reproductive organs (testes or ovary) or the embryo.

Systemic absorption of sulphuric acid, compound with graphite via any route of exposure can be excluded due to the physical-chemical properties of the substance and relevant exposure of workers can be excluded under normal or reasonably foreseeable conditions of use.
Against this background, based on the absence of bioavailability and toxicological activity of sulphuric acid, compound with graphite, it can be concluded that the substance is not systemically available, does not reach critical organs and tissues and thus has no adverse effects on sexual function and fertility in adults, and does not interfere with the normal development of their offspring.

Effects on developmental toxicity

Description of key information

According to REACH Regulation Article 13(1) “information shall be generated whenever possible by means other than vertebrate animal tests, through the use of alternative methods….. or from information from structurally related substances (grouping or read-across).”
The read-across approach can be applied on “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity... Application of the group concept requires that physicochemical properties, human health effects and environmental effects or environmental fate may be predicted from data for reference substance(s) within the group by interpolation to other substances in the group (read-across approach).
The toxicological profile of sulphuric acid, compound with graphite may be regarded as a combination of the individual toxicological properties of the constituents (graphite and sulphuric acid) and based on this structural relatedness read-across is being conducted to studies of graphite and sulphuric acid in order to determine effects on the reproductive performance.

Additional information

According to REACH Regulation Article 13(1)“information shall be generated whenever possible by means other than vertebrate animal tests, through the use of alternative methods….. or from information from structurally related substances (grouping or read-across).”

 

The read-across approach can be applied on “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity...Application of the group concept requires that physicochemical properties, human health effects and environmental effects or environmental fate may be predicted from data for reference substance(s) within the group by interpolation to other substances in the group (read-across approach). The similarities may be based on:

(1)   a common functional group, or

(2)   the common precursors and/or the likelihood of common breakdown products via physical and biological processes, which result in structurally similar chemicals;”

 

Sulphuric acid, compound with graphite is an inorganic solid, consisting of natural graphite and variable amounts of intercalated sulphuric acid.

Graphite is a naturally occurring solid substance which is insoluble in water. Due to its physico-chemical properties it is not systemically

and biologically available and does not cross biological membranes. In the aquatic compartment it can be considered as an inert substance. The intercalated sulphuric acid is partially leached out by water and dissociates into the biologically ubiquitous sulphate and hydronium ions.

 

The toxicological profile of sulphuric acid, compound with graphite may be regarded as a combination of the individual toxicological properties of the constituents (graphite and sulphuric acid) and based on this structural relatedness read-across is being conducted to studies of graphite and sulphuric acid in order to determine effects on the reproductive performance.

 

A study was performed at the Frauenhofer-Institute of Toxicology and Experimental Medicine to evaluate possible adverse effects of Expanded Graphite Powder after repeated exposure especially on male and female reproductive performance, such as gonadal function, mating behaviour, conception, development of the conceptus and parturition after exposure via food. The study was conducted following the OECD Guideline 422 "Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test" (March 1996).

The dose levels were based on a palatability study (Fraunhofer ITEM study no. 12N10002), in which the animals accepted food containing 10 g test item/kg food (estimated target dose of 1000 mg/kg/day) without any problems. The dose of 1000 mg/kg/day is also recommended as limit dose by OECD Guideline 422. Consequently, this dose was chosen as the high dose in the present study, and the actual concentration in food was determined based on actual body weights and food consumption data, which resulted in a value of 12 g/kg food. The other doses were determined using a stagger of approx. 3. The analyses showed that preparations contained 1300, 3700, and 11.500 mg/kg food (108, 103, and 96 % of the target concentration) for the three dose groups, respectively. Based on mean body weights and food consumption data, this resulted in the following actual substance intake: 91, 261, and 813 mg/kg body weight/day for males; 120, 343, and 1067 mg/kg body weight/day for females in the premating period; 106, 309, and 930 mg/kg body weight/day for females during gestation; and 111, 370, and 1159 mg/kg body weight/day for females during lactation, respectively. 

No effect of the test item exposure was observed on any of the investigated endpoints like precoital time or fertility (number of mated females, number of pregnant females, number of implantation sites, number of liveborn pups). No effect of the test item exposure could be observed on litter size and pup survival as well as pup body weight. None of the sporadically observed clinical findings in pups were considered test item related and no abnormal pups were observed. The main necropsy findings consisted in reduced size of testes and epidydimides, which were found in all groups including the control group. Sporadically observed statistically significant differences in organ weights were not considered an adverse effect of the test item exposure. Substance-related findings were not observed in the histologically examined organs of males and females of the control and high dose group.

Based on the results described above, the NOAEL for this study (parental, reproductive and developmental) was determined as the high (limit) target dose level of 12.000 mg/kg food (11.500 mg/kg food as determined by chemical analysis). This corresponds to the following actual substance intake: 813 mg/kg body weight/day for males; 1067 mg/kg body weight/day for females in the premating period, 930 mg/kg body weight/day for females during gestation and 1159 mg/kg body weight/day for females during lactation, respectively.

 

Analogously, a study with sulphuric acid was performed on mated female mice and inseminated female rabbits which were exposed (whole body) to atmospheres containing aerosols of sulphuric acid at 0, 5.7 mg/m³or 19.3 mg/m³on days 6-15 of gestication (mice) or on days 6-18 of gestication (rabbits). Exposures were conducted under dynamic airflow conditions in 4.3 m³ chambers. The chamber airflow was approximately 800 l/min. The aerosol was generated for each chamber by nebulising two molar sulphuric acid with a pneumatic atomizing nozzle.

No evidence of teratogenicity, embryotoxicity or developmental toxicity has been monitored under the conditions of the present study at exposure levels sufficient to cause mild maternal toxicity.

 

Taking into account the negative results of thedevelopmental toxicity studies for both graphite and sulphuric acid, and the structural similarities following Article 13(1) of the REACH Regulation it can be concluded that no further testing to determine the developmental toxicity/teratogenicity of sulphuric acid, compound with graphite needs to be conducted.

Justification for classification or non-classification

Taking into account the negative results of the developmental toxicity studies for both graphite and sulphuric acid, and the structural similarities following Article 13(1) of the REACH Regulation it can be concluded that sulphuric acid, compound with graphite has no potential of toxicity to reproduction. Against this background there are no classifictaion obligations according to the CLP Regulation.