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

Endpoint summary

Additional information

When sodium percarbonate comes into contact with the human skin or body fluids it will dissociate into hydrogen peroxide, carbonate ions and sodium ions. Human information about the toxicokinetics of these substances is available and was discussed in the OECD SIDS dossier (OECD 2006). The following paragraphs have been copied from the OECD SIDS dossier on sodium percarbonate (OECD 2006), section 3.1.1, page 11: “The toxicokinetics, metabolism and distribution of hydrogen peroxide have been described in detail by ECETOC (1993, 1996) and European Commission (2003). Hydrogen peroxide is a normal metabolite in the aerobic cell. There are a number of different hydrogen peroxide metabolizing systems, among them the enzymes catalase and glutathione peroxidase, which control the hydrogen peroxide concentration at different levels and in different parts of the cell as well as in the blood. Hydrogen peroxide will in part be decomposed by the cells of the tissue of first contact but the remaining part could diffuse into the blood vessels. However, the European Commission (2003) concluded “In view of the high-degradation capacity for hydrogen peroxide in blood it is however unlikely that the substance is systemically distributed, and therefore the endogenous steady state levels of the substance in tissues are unlikely to be affected“. The toxicokinetics, metabolism and distribution of carbonate have been described by the OECD (2002). Carbonate could potentially increase the pH of the blood. The blood plasma of man normally has a pH of 7.4. Should the pH fall below 7.0 or rise above 7.8, irreversible damage may occur. Compensatory mechanisms for acid-base disturbances return the pH of the blood to normal. If carbonate is absorbed its concentration will be regulated and therefore elevated amounts of carbonate are not expected to be available in the body. Furthermore it should be realised that an oral uptake of sodium percarbonate results in a neutralisation of carbonate in the stomach by the gastric acid. Significant amounts of gastric acids are present in the stomach (pH about 2) which will result in a formation of bicarbonate and/or carbon dioxide. Therefore it is very unlikely that an oral uptake of sodium percarbonate will result in a pH increase of the blood. Sodium ions are readily absorbed throughout the small intestine and are subject to rapid exchange by the large majority of cells in the body. Exposure to sodium percarbonate is not expected to contribute significantly to the sodium load of the body (compared to dietary uptake) and therefore elevated amounts of sodium are not expected to be available in the body.”