Disodium carbonate, compound with hydrogen peroxide (2:3)

Endpoint summary

Description of key information

It is expected that repeated dose toxicity of sodium percarbonate will be mainly mediated by hydrogen peroxide.

Additional information

The repeated dose toxicity of sodium percarbonate has not been tested for the oral, inhalation or dermal routes. In the OECD SIDS dossier on sodium percarbonate (OECD 2006) a read-across approach is chosen to close this data gap. Any potential repeated dose toxicity of sodium percarbonate in the dossier is attributed to the hydrogen peroxide released by the dissociation of the substance. Thus, an available 90-day drinking water study with hydrogen peroxide was used to derive a predicted NOAEL for sodium percarbonate of 308 ppm. This was based on the NOAEL of 100 ppm for hydrogen peroxide in drinking water for male and female C57BL/6NCrlBR mice. The hydrogen peroxide content in the sodium percarbonate of 32.5 % was taken to derive the NOAEL. The EU risk assessment for hydrogen peroxide (European Commission 2003, page 122) says that “repeated exposure inhalation toxicity of hydrogen peroxide is not well elucidated and singular, limited studies with rats and dogs suggest that local effects in the skin, the respiratory tract, and the lungs may occur at about 10 mg/m3”.

Information about the repeated dose toxicity of sodium carbonate is available for the oral and inhalation routes. According to the OECD SIDS dossier, repeated oral administration to pregnant mice of aqueous solutions of sodium carbonate at concentrations ranging from 3.4 to 340 mg/kg body weight had no adverse effects to the dams and litters (OECD 2002). Repeated inhalation of sodium carbonate may produce local effects in the respiratory tract. According to the OECD SIDS dossier for sodium carbonate (OECD 2002), prolonged repeated dose inhalation exposure (3.5 months, 5 days/week, 4 hours/day) to sodium carbonate (applied as aqueous aerosols with a 2 % concentration) lead to local effects in the respiratory tract of male rats.

Justification for classification or non-classification

In consideration of the quality of the available data on the repeated dose toxicity of hydrogen peroxide and sodium carbonate the read-across approach taken in the OECD SIDS dossier is followed to conclude on the repeated dose toxicity of sodium percarbonate. The following text is copied from the OECD SIDS dossier for sodium percarbonate (OECD 2006), section 3.1.5, page 18:

"Although a repeated dose study is not available for sodium percarbonate, an additional repeated dose toxicity study in rats with sodium percarbonate is not necessary because the effects can be predicted based on the release of hydrogen peroxide, carbonate and sodium. As it is expected that repeated dose toxicity of sodium percarbonate will mainly be mediated by hydrogen peroxide, no observed adverse effect levels can be defined on the basis of its hydrogen peroxide content. Based on the 90-day drinking water study according to OECD guidelines and GLP with hydrogen peroxide and catalase deficient mice, the predicted NOAEL of sodium percarbonate would be 308 ppm (81 to 115 mg/kg bw/day for males and females, respectively)."