RISK ASSESSMENT REPORT ZINC OXIDE CAS-No
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RISK ASSESSMENT REPORT ZINC OXIDE CAS-No.: 1314-13-2 EINECS-No.: 215-222-5 GENERAL NOTE This document contains: - part I Environment (pages 74) - part II Human Health (pages 162) R073_0805_env RISK ASSESSMENT ZINC OXIDE CAS-No.: 1314-13-2 EINECS-No.: 215-222-5 Final report, May 2008 PART 1 Environment Rapporteur for the risk evaluation of zinc oxide is the Ministry of Housing, Spatial Planning and the Environment (VROM) in consultation with the Ministry of Social Affairs and Employment (SZW) and the Ministry of Public Health, Welfare and Sport (VWS). Responsible for the risk evaluation and subsequently for the contents of this report is the rapporteur. The scientific work on this report has been prepared by the Netherlands Organization for Applied Scientific Research (TNO) and the National Institute of Public Health and Environment (RIVM), by order of the rapporteur. Contact point: Bureau Reach P.O. Box 1 3720 BA Bilthoven The Netherlands R073_0805_env PREFACE For zinc metal (CAS No. 7440-66-6), zinc distearate (CAS No. 557-05-1 / 91051-01-3), zinc oxide (CAS No.1314-13-2), zinc chloride (CAS No.7646-85-7), zinc sulphate (CAS No.7733- 02-0) and trizinc bis(orthophospate) (CAS No.7779-90-0) risk assessments were carried out within the framework of EU Existing Chemicals Regulation 793/93. For each compound a separate report has been prepared. It should be noted, however, that the risk assessment on zinc metal contains specific sections (as well in the exposure part as in the effect part) that are relevant for the other zinc compounds as well. For these aspects, the reader is referred to the risk assessment report on zinc. 2 CAS No. 1314-13-2 R073_0805_env CONTENTS 0 OVERALL CONCLUSIONS/RESULTS OF THE RISK ASSESSMENT 5 1 GENERAL SUBSTANCE INFORMATION 7 1.1 Identification of the substance 7 1.2 Environmental classification and labelling of zinc oxide 9 1.2.1 Introduction 9 1.2.2 Dissolution test results 9 1.2.3 Result short-term toxicity tests 10 1.2.4 Conclusion and discussion 11 2 GENERAL INFORMATION ON EXPOSURE 12 2.1 Production 12 2.2 Use pattern 12 3 ENVIRONMENT 15 3.1 General introduction 15 3.2 Exposure assessment 16 3.2.1 Exposure scenarios 17 3.2.1.1 General 17 3.2.1.2 Local exposure assessment 19 3.2.1.2.1 General 19 3.2.1.2.2 Production of zinc oxide 20 3.2.1.2.3 General information on the use categories of zinc oxide in the EU 29 3.2.1.2.4 Processing in automobile tyres 30 3.2.1.2.5 Processing in general rubber 31 3.2.1.2.6 Processing in glass 33 3.2.1.2.7 Processing in ceramics 34 3.2.1.2.8 Processing in ferrites 35 3.2.1.2.9 Processing in varistors 36 3.2.1.2.10 Processing in catalysts 38 3.2.1.2.11 Formulation as feedstuff additive 39 3.2.1.2.12 Formulation and processing in zinc chemicals 40 3.2.1.2.13 Formulation and processing in lubricant additives 40 3.2.1.2.14 Formulation and processing in paints 42 3.2.1.2.15 Formulation in cosmetics and pharmaceuticals 44 3.2.1.2.16 Measured local data in the environment 45 3.2.1.2.17 Summary of results for the local exposure assessment 46 3.3 Effects Assessment 48 3.3.1 Aquatic and terrestrial compartment 48 3.3.1.1 Zinc oxide 48 3.3.1.1.1 Aquatic compartment 48 3.3.1.1.2 Terrestrial compartment 52 3 CAS No. 1314-13-2 R073_0805_env 3.3.1.2 Zinc 53 3.3.2 Atmosphere 54 3.3.3 Secondary poisoning 54 3.4 Risk characterisation 55 3.4.1 General 55 3.4.2 Local risk characterisation 61 3.4.2.1 Aquatic compartment 61 3.4.2.1.1 STP effluent 61 3.4.2.1.2 Surface water (incl. sediment) 61 3.4.2.2 Terrestrial compartment 62 3.4.2.3 Atmospheric compartment 63 3.4.2.4 Secondary poisoning 63 3.4.3 Regional risk characterisation 66 APPENDIX 3.4 BIOAVAILABILITY CORRECTIONS 67 4 REFERENCES 69 5 ANNEX 1.3.1 DISSOLUTION TESTS WITH ZINC OXIDE 72 4 CAS No. 1314-13-2 R073_0805_env 0 OVERALL CONCLUSIONS/RESULTS OF THE RISK ASSESSMENT CAS No. 1314-13-2 EINECS No. 215-222-5 IUPAC Name Zinc oxide ( ) i) There is need for further information and/or testing (X) ii) There is at present no need for further information and/or testing and for risk reduction measures beyond those which are being applied already (X) iii) There is a need for limiting the risks; risk reduction measures which are already being applied shall be taken into account (X) iii*) A conclusion applied to local scenarios in which the local scenario merits conclusion (ii) but where (possibly) due to high regional background concentrations a local risk cannot be excluded. LOCAL Conclusion (ii) is drawn for all local scenarios, including secondary poisoning, except those listed below. Conclusion iii) or iii*) is drawn for the specified scenarios, because: STP • the PECSTP exceeds the PNECadd for microorganisms in a number of processing scenarios listed in Table 3.4.19 (conclusion iii). Surface water • the Clocaladd in water exceeds the PNECadd for surface water in a number of processing scenarios listed in Table 3.4.19 (conclusion iii). For one other processing scenario listed in Table 3.4.19 the Clocaladd / PNECadd ratio is between 0.5 and 1, indicating that a potential risk at local scale cannot be excluded due to the possibly existence of high regional background concentrations (conclusion iii*). Sediment • the Clocaladd in sediment exceeds the PNECadd at one production site and in a number of processing scenarios listed in Table 3.4.19 (conclusion iii). For the remaining processing scenarios and production sites listed in Table 3.4.19 (and having emissions to water) the Clocaladd / PNECadd ratio is below 1, but a potential risk at local scale cannot be excluded due to the possible existence of high regional background concentrations (conclusion iii*). 5 CAS No. 1314-13-2 R073_0805_env Soil • the PEClocaladd in soil exceeds the PNECadd in a number of processing scenarios listed in Table 3.4.19 (conclusion iii). REGIONAL The regional risk characterisation is discussed in the RAR on Zinc Metal. 6 CAS No. 1314-13-2 R073_0805_env 1 GENERAL SUBSTANCE INFORMATION 1.1 IDENTIFICATION OF THE SUBSTANCE CAS-No.: 1314-13-2 EINECS-No.: 215-222-5 IUPAC name: zinc oxide Synonyms: zinc white Molecular formula: ZnO Structural formula: ZnO Molecular weight: 81.38 Purity/impurities, additives Purity: >93 % Impurity: According to the companies several impurities might occur Impurity* CAS-No. Quantity (% w/w) Water < 4 Zinc carbonates < 2 Iron oxide (as iron) 7439-89-6 < 0.2 Lead oxide (as lead) 1317-36-8 < 0.5 Cadmium oxide (as cadmium) 7440-43-9 < 0.07 *Different impurities may be found in different batches and are depending on the process Additives: Additive* CAS-No. Quantity (%w/w) Distillates (naphthenic mineral oils) 0.2 - 5 Blends of inorganic compounds 0.2 - 4 Blends of aliphatic or aromatic carboxylic acids 0.2 - 2 *Different additives may be found in different batches Physico-chemical properties In table 1A the physico-chemical properties are summarized. 7 CAS No. 1314-13-2 R073_0805_env Table 1A Physico-chemical properties of zinc oxide Property Result Comment Physical state solid, powder * Melting point > 1975 °C (high pressure) ** Boiling point Not applicable **** Relative density 5.6 * Vapour pressure Not applicable *** Surface tension Not applicable **** Water solubility < 1.6 mg/l + Solubility in other solvents Insoluble in alcohol; soluble in acids * Partition coefficient Not applicable **** n-octanol/water (log value) Flash point Not applicable **** Flammability Not flammable **** Autoflammability temperature Not applicable **** Explosive properties Not explosive **** Oxidizing properties Not oxidizing **** Granulometry Particle size: 100-10000 nm ***** * More than one apparently independent source. No methods are specified. ** Several values found in literature. Sublimation will occur at temperatures lower than melting temperature. *** Not relevant at ambient temperature. **** Conclusion based on theoretical, and/or structural considerations. ***** Several values found in literature, all in the same range. + solubility depending on mass loading and type of water medium (LISEC-REPORT, 1997). These data are mainly derived from MSDS’s and from CRC Handbook of Chemistry and Physics (1995), Sax’s Dangerous Properties of Industrial Materials (1984), Patty’s Industrial Hygiene and Toxicology (1981), and Ullmann’s Encyklopädie der Technischen Chemie (1983). For an extended description see HEDSET. Conclusion: Data on boiling point, vapour pressure, surface tension, and partition coefficient were not provided. In view of the nature of the substance determination of these parameters is 8 CAS No. 1314-13-2 R073_0805_env considered to be irrelevant. Information on flammability, explosive properties and oxidizing properties is not available. However, on theoretical considerations the compound is concluded to be not flammable, not explosive and not oxidizing. All other required physico-chemical data were submitted. None of these data is based on test results, substantiated with reports. However, the data are considered as sufficiently reliable to fulfil the Annex VIIA requirements. 1.2 ENVIRONMENTAL CLASSIFICATION AND LABELLING OF ZINC OXIDE 1.2.1 Introduction For a general introduction on the classification and labelling of metals, the reader is referred to sections 1.2.1 and 1.2.2 of the risk assessment report on zinc metal. 1.2.2 Dissolution test results Dissolution of zinc from zinc oxide A dissolution test report from LISEC (October, 1997) is available for zinc oxide.