FOREWORD INTRODUCTION - inchem.org

1 OECD SIDSSODIUM BICARBONATEUNEP PUBLICATIONS1 FOREWORDINTRODUCTIONSODIUM BICARBONATECAS N : 144-55-8 OECD SIDSSODIUM BICARBONATEUNEP Publications2 SIDS Initial Assessment ReportForSIAM 15(Boston, USA, 22-25 October 2002)Chemical Name:Sodium bicarbonateCAS No:144-55-8 Sponsor country:B e lgiumNational SIDS Contact Point: Dr. of Social Affairs, Public Health and EnvironmentScientific Institute of Public Health Division ToxicologyRue J. Wytsman 16, B-1050 BrusselsTel. + 32 2 642 5104, fax. + 32 2 642 5224, draft dossier was prepared by a consultant (TNO Chemistry,Zeist, The Netherlands). After a quality check of the IUCLID, SIAR, SIAP and Summary Table by the industry, the dossier was submitted in June 2002 to the sponsor country.

2 On behalf of the sponsor country 2 experts (human health, environment) reviewed the dossier. Thesponsor country and the industry consortium leader had been workingtogether already for another ICCA HPV chemical (KOH), whichfacilitated the :The substance is an ICCA HPV chemical. Industry did the literature search and collected all references. The consultant received theliterature and prepared the draft dossier. The dossier of sodiumcarbonate (CAS number 497-19-8) was developed in parallel using asimilar new SIDS testing conducted(X)New SIDST esting conducted( ) Comments:Date of first Submission: 6 August 2002 OECD SIDSSODIUM BICARBONATEUNEP Publications3 SIDS INITIAL ASSESSMENT PROFILECAS Name Sodium bicarbonateStructural FormulaNaHCO3 SUMMARY CONCLUSIONS OF THE SIARS odium bicarbonate is a white, odourless, crystalline powder.

3 It decomposes when heated over50oC and therefore a melting and boiling point can not be determined. Sodium bicarbonate is aninorganic salt and therefore the vapour pressure can be considered negligible. Its water solubilityis 96 g/l at 20oC. Grades with different average particle size diameters (d50) are placed on themarket. The average particle size diameter of the different sodium bicarbonate grades can rangebetween 15 and 300 HealthOral LD50 values were higher than 4,000 mg/kg bw, and an inhalation study in rats using aconcentration of mg/l inhalable dust produced no deaths.

4 There are no directly relevant studies on repeated dose exposure, however, knowledge of prioruse and available literature does not indicate any adverse effects of long-term use of exposurevia any route. In vitro bacterial and mammalian cell tests showed no evidence of genotoxicactivity. As with other sodium salts, high doses of sodium bicarbonate promote carcinomaformation in rat urinary bladder after pre-exposure to initiator or BBN. However, when rats were only exposed to sodium bicarbonate no carcinogenic effect on the urinary bladder was on the available information there are no indications that sodium bicarbonate hascarcinogenic bicarbonate has a long history of use in foodstuff, feed and industrial processes.

5 Thebicarbonate ion is a normal constituent in vertebrates, as the principal extracellular buffer in theblood and interstitial fluid is the bicarbonate buffer system. Excess sodium and bicarbonate ionsare readily excreted in the urine. It is therefore assumed that normal handling and use will not have any adverse effects. The consequences of accidental or excessive oral ingestion have beendescribed in a number of publications. Acute oral ingestion by the patients may result in aruptured stomach due to excessive gas development. Acute or chronic excessive oral ingestionmay cause metabolic alkalosis, cyanosis and hypernatraemia.

6 These conditions are usuallyreversible, and will not cause adverse NOEC values to fish and daphnids are higher than 1,000 mg/l. The 21-day NOEC toDaphnia magna is higher than 576 mg/l. The acute toxicity of sodium bicarbonate for aquaticorganisms could be based on a high osmotic pressure. This is a very general effect of salts assoon as their concentration in water exceeds a certain level. OECD SIDSSODIUM BICARBONATEUNEP Publications4 Both sodium and bicarbonate are present naturally present in aquatic ecosystems. For sodium the10th- and 90th-percentile were and 68 mg/l, respectively, based on a total number of 75 rivers.

7 For bicarbonate the 10th- and 90th-percentile were 20 and 195 mg/l, respectively, based on a totalnumber of 77 rivers. Because the natural pH, bicarbonate and sodium concentration (and alsotheir fluctuations in time) varies significantly between aquatic ecosystems, it is not considereduseful to derive a generic PNEC or PNEC added. To assess the potential environmental effect of a sodium bicarbonate discharge, the increase in sodium, bicarbonate and pH should be comparedwith the natural values and their fluctuations and based on this comparison it should be assessedif the anthropogenic addition is acceptable.

8 The production and use of sodium bicarbonate could potentially result in an emission of sodiumbicarbonate to aquatic and terrestrial ecosystems. However, for most applications the bicarbonatewill be digested (animal feeding, human food, pharmaceuticals) or treated by a waste watertreatment plant (detergents and household cleaning products) and will not be directly emitted tothe ecosystems. In order to determine if the production and use of sodium bicarbonate reallyresults in a significant emission of bicarbonate, an evaluation of the complete, inorganic andorganic carbon cycle would be sodium emissions originating from uses of sodium bicarbonate are probably smallcompared to other sources.

9 It is clear that an environmental hazard assessment of sodium shouldnot only evaluate all natural and anthropogenic sources of sodium but should also evaluate allother ecotoxicity studies with sodium salts, which is beyond the scope of this bicarbonate is produced on all continents of the world and the global number ofproduction sites is estimated to be 30-50. The estimated total amount of sodium bicarbonate usedin 2001 is 2 million bicarbonate is used as animal feed additive, human food additive and it is used inpharmaceuticals.

10 It is also used for the production of other chemicals and it used in cosmeticsand detergents and other household cleaning products. It is present in a large number ofconsumer products but the pure product is also available to chemical is currently of low priority for further FOR THE RECOMMENDATION AND NATURE OF FURTHER WORK RECOMMENDEDThis chemical is currently considered of low priority for further work because of its low SIDSSODIUM BICARBONATEUNEP Publications5 FULL SIDS SUMMARYCAS N pointNo pointNo (at 20 C) pressureNo dataNegligible, ionizable inorganic dataNot relevant, ionizable inorganic solubilityNo data69 g/l (at 0 C)96 g/l (at 20 C)165 g/l (at 60 C)