February 2021 1 ALUMINIUM OXIDE This Dossier on Aluminium
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ALUMINIUM OXIDE This dossier on aluminium oxide presents the most critical studies pertinent to the risk assessment of aluminium oxide in its use in drilling muds. This dossier does not represent an exhaustive or critical review of all available data. The majority of information presented in this dossier was obtained from the ECHA database that provides information on chemicals that have been registered under the EU REACH (ECHA). Where possible, study quality was evaluated using the Klimisch scoring system (Klimisch et al., 1997). Screening Assessment Conclusion – Aluminium oxide is classified as a tier 1 chemical and requires a hazard assessment only. 1 BACKGROUND Aluminium oxide or alumina, (Al2O3), is an inert, odourless, white amorphous material often used in industrial ceramics. Due to its outstanding properties, alumina has contributed to a significant number of life-extending and society-enhancing applications. It is of little toxicological concern to humans and the environment. Due to aluminium oxide’s hardness, bio-inertness and chemical properties, it is a preferred material for bearings in hip replacements, as prostheses, bionic implants, prosthetic eye substitutes, tissue reinforcements, dental crowns, abutments, bridges and other dental implants. It is also used in lab equipment and tools like crucibles, furnaces and other labware. 2 CHEMICAL NAME AND IDENTIFICATION Chemical Name (IUPAC): oxo[(oxoalumanyl)oxy]alumane CAS RN: 1344-28-1 Molecular formula: Al2O3 Molecular weight: 101.961 g/mol Synonyms: Bauxite, Ceramic-Alumina, Corundum, Oxide, Aluminium 3 PHYSICO-CHEMICAL PROPERTIES Key physical and chemical properties for the substance are shown in Table 1. Table 1 Overview of the Physico-chemical Properties of Aluminium Oxide Property Value Klimisch score Reference Physical state at 20oC and 101.3 kPa White, odourless powder 1 ECHA Melting Point 2,054oC (pressure not provided) 1 ECHA Revision date: February 2021 1 Property Value Klimisch score Reference Boiling Point 2,977oC @101.3 kPa (assumed 1 ECHA pressure) Density >3970 - < 3990 kg/m³@ 20oC 1 ECHA Vapour Pressure 0 Pa @ 25oC 1 ECHA Partition Coefficient (log Kow) The study does not need to be - ECHA- conducted because the substance is inorganic. Water Solubility 0 g/L@ 20oC 1 ECHA Dissociation Constant (pKa) The study does not need to be - ECHA conducted because the substance is insoluble 4 DOMESTIC AND INTERNATIONAL REGULATORY INFORMATION A review of international and national environmental regulatory information was undertaken (Table 2). This chemical is listed on the Australian Inventory of Chemical Substances – AICS (Inventory). No conditions for its use were identified. No specific environmental regulatory controls or concerns were identified within Australia and internationally for aluminium oxide. Table 2 Existing International Controls Convention, Protocol or other international control Listed Yes or No? Montreal Protocol No Synthetic Greenhouse Gases (SGG) No Rotterdam Convention No Stockholm Convention No REACH (Substances of Very High Concern) No United States Endocrine Disrupter Screening Program No European Commission Endocrine Disruptors Strategy No 5 ENVIRONMENTAL FATE SUMMARY A. Summary Aluminium oxide is an inorganic substance that is not subject to biodegradation, is not expected to bioaccumulate, and has a low potential to adsorb to soil. B. Biodegradation Aluminium oxide is an inorganic substance. According to Annex VII of the REACH regulations (ECHA), biodegradation testing for inorganic chemicals is not required. Revision date: February 2021 2 C. Environmental Distribution Environmental distribution or mobility of a substance is mainly driven by the adsorption potential. The potential of aluminium for adsorption to sediment and soil particles is mainly driven by its speciation and the concentration of dissolved organic carbon (DOC) (ECHA). For evaluation of adsorption at different pH-levels a chemical simulation was performed. In the stimulation, the amount of aluminium bound to particles as a result of surface complexation (i.e. adsorption) was pH dependent, but was typically less than 8% of the total aluminium at pH 6, and was further reduced to below 1% at pH values above 7. This distribution was similar in both soft and hard waters. The corresponding Log Kd values for this distribution are between 3 and 5. Very similar results were obtained with higher DOC concentrations of 4 mg/L (ECHA)[Kl Score =2]. D. Bioaccumulation The available evidence shows the absence of aluminium biomagnification across trophic levels both in aquatic and terrestrial food chains. The existing information suggests not only that aluminium does not biomagnify, but rather that it tends to exhibit biodilution at higher trophic levels in the food chain (ECHA) [Kl Score =2]. 6 ENVIRONMENTAL EFFECTS SUMMARY A. Summary Aluminium oxide is of low acute toxicity concern to aquatic organisms, in part because of the effect of pH changes from the dissociated hydrogen ion. B. Aquatic Toxicity Acute Studies Data available on aluminium oxide have been generated to demonstrate bioavailability of aluminium in acid water. Adequate studies were found to evaluate the intrinsic toxicity of aluminium oxide. Nonetheless, aluminium oxide is not expected to pose a substantial acute toxicity concern to aquatic receptors (ECHA) [Kl Score =2]. Chronic Studies No studies are available. Terrestrial Toxicity No data are available. Revision date: February 2021 3 7 CATEGORISATION AND OTHER CHARACTERISTICS OF CONCERN A. PBT Categorisation The methodology for the Persistent, Bioaccumulative and Toxic (PBT) substances assessment is based on the Australian and EU REACH Criteria methodology (DEWHA, 2009; ECHA, 2008). Aluminium oxide is an inorganic mineral. Thus, biodegradation is not applicable to this substance. For the purposes of this PBT assessment, the persistent criteria are not considered applicable to aluminium oxide. Aluminium oxide is a naturally inorganic substance and as an inorganic complex is not expected to bioaccumulate. Thus, aluminium oxide does not meet the screening criteria for bioaccumulation. Thus, aluminium oxide is not a PBT substance. B. Other Characteristics of Concern No other characteristics of concern were identified for aluminium oxide. Revision date: February 2021 4 8 SCREENING ASSESSMENT Chemical Databases of Concern Bioaccumulative Persistence Assessment Step Toxicity Assessment Step Assessment Step Assessment Step Overall PBT Risk Assessment Actions Chemical Name CAS No. Listed as a COC Identified as Assessment 1 P criteria Other P T criteria Acute Chronic Required3 on relevant Polymer of Low B criteria fulfilled? fulfilled? Concerns fulfilled? Toxicity 2 Toxicity2 databases? Concern Aluminium oxide 1344-28-1 Not a PBT No No NA No No No 1 1 1 Footnotes: 1 - PBT Assessment based on PBT Framework. 2 - Acute and chronic aquatic toxicity evaluated consistent with assessment criteria (see Framework). 3 – Tier 1 – Hazard Assessment only. Notes: NA = not applicable PBT = Persistent, Bioaccumulative and Toxic B = bioaccumulative P = persistent T = toxic Revision date: February 2021 5 9 REFERENCES, ABBREVIATIONS AND ACRONYMS A. References Department of the Environment, Water, Heritage and the Arts [DEWHA]. (2009). Environmental risk assessment guidance manual for industrial chemicals, Department of the Environment, Water, Heritage and the Arts, Commonwealth of Australia. ECHA. ECHA REACH database: http://echa.europa.eu/information-on-chemicals/registered- substances European Chemicals Agency [ECHA]. (2008). Guidance on Information Requirements and Chemical Safety Assessment, Chapter R11: PBT Assessment, European Chemicals Agency, Helsinki, Finland. Klimisch, H.J., Andreae, M., and Tillmann, U. (1997). A systematic approach for evaluating the quality of experimental and toxicological and ecotoxicological data. Regul. Toxicol. Pharmacol. 25:1-5. B. Abbreviations and Acronyms °C degrees Celsius AICS Australian Inventory of Chemical Substances COC constituent of concern DEWHA Department of the Environment, Water, Heritage and the Arts DOC dissolved organic carbon ECHA European Chemicals Agency EU European Union g/L grams per litre hPa hectopascal IUPAC International Union of Pure and Applied Chemistry kg/m3 kilogram per cubic metre Kl Klimisch scoring system kPa kilopascal mg/L milligrams per litre PBT Persistent, Bioaccumulative and Toxic REACH Registration, Evaluation, Authorisation and Restriction of Chemicals SGG Synthetic Greenhouse Gases Revision date: February 2021 6 .