Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) JACC No. 55 EUROPEAN CENTRE FOR ECOTOXICOLOGY AND TOXICOLOGY OF CHEMICALS Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) JACC No. 55 Brussels, December 2011 ISSN-0773-6339-55 print ISSN-2079-1496-55 online Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) ECETOC JACC REPORT No. 55 © Copyright – ECETOC AISBL European Centre for Ecotoxicology and Toxicology of Chemicals 4 Avenue E. Van Nieuwenhuyse (Bte 6), B-1160 Brussels, Belgium. All rights reserved. No part of this publication may be reproduced, copied, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the copyright holder. Applications to reproduce, store, copy or translate should be made to the Secretary General. ECETOC welcomes such applications. Reference to the document, its title and summary may be copied or abstracted in data retrieval systems without subsequent reference. The content of this document has been prepared and reviewed by experts on behalf of ECETOC with all possible care and from the available scientific information. It is provided for information only. ECETOC cannot accept any responsibility or liability and does not provide a warranty for any use or interpretation of the material contained in the publication. ECETOC JACC No. 55 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) CONTENTS EXECUTIVE SUMMARY 1 THE ECETOC SCHEME FOR THE JOINT ASSESSMENT OF COMMODITY CHEMICALS 2 1. SUMMARY AND CONCLUSIONS 3 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 5 2.1 Identity 5 2.2 EU classification and labelling 7 2.3 Physical and chemical properties 8 2.3.1 Solubility in water 9 2.3.2 Partition coefficient octanol-water 10 2.3.3 Sorption to solid-phase organic matter 11 2.4 Conversion factors 13 2.5 Analytical methods 13 2.5.1 General considerations 13 2.5.2 Extraction procedures 14 2.5.3 Conversion of analytical results to PDMS 15 2.6 Summary and evaluation 16 3. PRODUCTION, STORAGE AND HANDLING, TRANSPORT AND USE 17 3.1 Production 17 3.2 Storage and handling 17 3.3 Transport 18 3.4 Use 19 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, TRANSFORMATION AND IMPACT 21 4.1 Emissions 21 4.1.1 Natural sources 21 4.1.2 Emissions during production and use 21 4.2 Environmental distribution 22 4.2.1 EQC modelling 23 4.3 Environmental fate and biotransformation 24 ECETOC JACC No. 55 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) 4.3.1 Atmospheric fate 24 4.3.2 Aquatic fate 24 4.3.3 Terrestrial fate 25 4.3.4 Degradation dimethylsilanediol 27 4.3.5 Bioaccumulation 29 4.3.6 Summary and evaluation 32 5. ENVIRONMENTAL CONCENTRATIONS AND HUMAN EXPOSURE 34 5.1 Environmental concentrations 34 5.1.1 Air 34 5.1.2 Water 34 5.1.3 Sediment 35 5.1.4 Sewage sludge 37 5.1.5 Soil 37 5.1.6 Biota 38 5.2 Human exposure concentrations and hygiene standards 38 5.2.1 Non-occupational exposure 38 5.2.2 Occupational exposure 42 5.2.3 Hygiene standards 42 5.3 Summary and evaluation 42 6. EFFECTS ON ORGANISMS IN THE ENVIRONMENT 43 6.1 Micro-organisms 43 6.2 Aquatic organisms 44 6.2.1 Fish 44 6.2.2 Invertebrates 44 6.2.3 Algae 45 6.2.4 Conclusions on aquatic phase 46 6.3 Sediment organisms 46 6.3.1 Conclusions on sediment phase 48 6.4 Terrestrial organisms 48 6.4.1 Soil organisms 48 6.4.2 Insects 50 6.5 Calculation of PNEC 51 ECETOC JACC No. 55 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) 6.5.1 Aquatic phase 51 6.5.2 Sediment phase 51 6.5.3 Terrestrial phase 51 7. KINETICS AND METABOLISM 52 7.1 Animal studies 52 7.2 Human studies 53 8. EFFECTS ON EXPERIMENTAL ANIMALS AND IN VITRO TEST SYSTEMS 54 8.1 Single exposure 54 8.1.1 Oral 54 8.1.2 Dermal 55 8.1.3 Inhalation 55 8.1.4 Intraperitoneal 56 8.1.5 Subcutaneous 57 8.2 Skin, respiratory tract and eye irritation, sensitisation 57 8.2.1 Skin irritation 58 8.2.2 Eye irritation 59 8.2.3 Vaginal irritation 63 8.2.4 Skin sensitisation 64 8.3 Repeated exposure 64 8.3.1 Subacute Toxicity 64 8.3.2 Subchronic Toxicity 65 8.3.3 Chronic 67 8.4 Genotoxicity and cell transformation 68 8.4.1 In vitro 68 8.4.2 In vivo 69 8.5 Chronic toxicity and carcinogenicity 69 8.6 Embryo toxicity, teratology and reproductive performance 70 8.6.1 Reproductive 70 8.6.2 Teratogenicity 71 8.7 Immunotoxicity 72 8.8 Special studies 73 8.9 Summary and evaluation 74 9. EFFECTS ON HUMANS 75 9.1 Skin irritation 75 ECETOC JACC No. 55 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) 9.2 Skin sensitisation 75 9.3 Chronic exposure, medical and surgical use 76 9.3.1 Urology 76 9.3.2 Ophtalmology 76 9.3.3 Dermatology 78 9.3.4 Dietary studies 79 9.4 Immunology 80 9.5 Chronic exposure 81 9.5.1 Occupational 81 9.5.2 Non-occupational 81 10. HAZARD (RISK) ASSESSMENT 94 10.1.1 PNEC calculations 95 10.1.2 PEC calculations 96 10.1.3 Risk characterisation ratio 97 11. BIBLIOGRAPHY 101 11.1 References quoted 101 11.2 References not quoted 118 11.3 Databases consulted 130 APPENDIX A: SYMBOLS, UNITS AND ABBREVIATIONS 131 APPENDIX B: CRITERIA FOR RELIABILITY CATEGORIES 134 MEMBERS OF THE TASK FORCE 135 MEMBERS OF THE SCIENTIFIC COMMITTEE 136 ECETOC JACC No. 55 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) EXECUTIVE SUMMARY This report presents a critical evaluation of the toxicity, physico-chemical properties, and environmental fate and effects of linear polydimethylsiloxanes (PDMSs), a type of non-volatile (odourless), fluid (viscous) “silicones” that are virtually insoluble in water. PDMSs are widely used in industrial, consumer, food and medicinal or pharmaceutical applications. The report has been produced as part of the ECETOC Joint Assessment of Commodity Chemicals (JACC) programme and updates an earlier ECETOC review a. Almost all PDMS discarded ʽdown-the-drain’ is expected to be removed during sewage treatment. Any PDMS released into the environment will strongly sorb to particulate matter in water and soil. PDMSs are immobile in soil and sediment, but will break down slowly (abiotic) to dimethylsilanediol, which is soluble in water and can biodegrade to carbon dioxide, water and inorganic silicate, as demonstrated in the laboratory. Due to its molecular size, bioconcentration of PDMS is very unlikely. PDMSs are not detected in surface waters, except at low concentrations downstream from wastewater treatment plants. PDMS has no effects when tested on aquatic organisms (fish, daphnia, algae), sediment-dwelling organisms (e.g. midge larva) and little or no effect on soil organisms (e.g. earthworm). PDMS is lethal to insects when applied directly, probably due to a physical rather than toxicological action. Humans may be exposed to PDMS via oral ingestion and dermal contact. In laboratory animals, PDMS had a low potential for absorption via these routes. Swallowed PDMS is rapidly excreted unchanged in the faeces. Aerosolised PDMS may give rise to inhalation exposure, but there is no indication of any adverse effects. PDMS is not a skin irritant or a skin sensitiser and it is only mildly to non-irritating to the eyes. Acute and repeated dose toxicity studies conducted in laboratory animals on PDMS of different viscosities do not show any significant adverse effects. Long-term chronic/carcinogenicity and reproductive toxicity studies were also without adverse effects. PDMS is not mutagenic in vitro. In humans, PDMS has no effect on the immune system. PDMS is used in urology, ophthalmology and dermatology (skin correction). Autoimmune disorders (e.g. scleroderma) cannot be linked to PDMS. Several human diseases (connective tissue, atypical connective tissue, rheumatic and autoimmune diseases, and breast cancer) have been reported after injection of PDMS (for cosmetic purposes) or placement of breast implants (made of high viscosity PDMS). These diseases are, however, not associated with PDMS. Overall, PDMS does not present a risk to the environment or to human health. a ECETOC. 1994. Joint Assessment of Commodity Chemicals No. 26 ECETOC JACC No. 55 1 Linear Polydimethylsiloxanes CAS No. 63148-62-9 (Second Edition) THE ECETOC SCHEME FOR THE JOINT ASSESSMENT OF COMMODITY CHEMICALS This report has been produced as part of the ECETOC programme for preparing critical reviews of the toxicology and ecotoxicology of selected existing industrial chemicals. In the programme, commodity chemicals (i.e. those produced in large tonnage by several companies and having widespread and multiple uses) are jointly reviewed by experts from a number of companies with knowledge of the chemical. It should be noted that in a JACC review only the chemical itself is considered; products in which it appears as a component or an impurity are not normally taken into account. This report presents a critical evaluation of the available data on the toxicity, physico-chemical properties, and environmental fate and effects of linear polydimethylsiloxane (PDMS) (CAS No. 63148-62-9). It updates an earlier ECETOC review a. A list of symbols, units and abbreviations is given in Appendix A. Where relevant, the Task Force has graded the studies by means of a ‘code of reliability’ (CoR) to reflect the degree of confidence that can be placed on the reported results.