Environmental Health Criteria 65 BUTANOLS: FOUR ISOMERS - 1-Butanol - 2-Butanol - tert-Butanol - Isobutanol Please note that the layout and pagination of this web version are not identical with the printed version. Butanols - four isomers (EHC 65, 1987) INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY ENVIRONMENTAL HEALTH CRITERIA 65 BUTANOLS: FOUR ISOMERS - 1-Butanol - 2-Butanol - tert-Butanol - Isobutanol This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organisation, or the World Health Organization. Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization World Health Orgnization Geneva, 1987 The International Programme on Chemical Safety (IPCS) is a joint venture of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization. The main objective of the IPCS is to carry out and disseminate evaluations of the effects of chemicals on human health and the quality of the environment. Supporting activities include the development of epidemiological, experimental laboratory, and risk-assessment methods that could produce internationally comparable results, and the development of manpower in the field of toxicology. Other activities carried out by the IPCS include the development of know-how for coping with chemical accidents, coordination of laboratory testing and epidemiological studies, and promotion of research on the mechanisms of the biological action of chemicals. ISBN 92 4 154265 9 The World Health Organization welcomes requests for permission to reproduce or translate its publications, in part or in full. Applications and enquiries should be addressed to the Office of Publications, World Health Organization, Geneva, Switzerland, which will be glad to provide the latest information on any changes made to the text, plans for new editions, and reprints and translations already available. Page 1 of 75 Butanols - four isomers (EHC 65, 1987) (c) World Health Organization 1987 Publications of the World Health Organization enjoy copyright protection in accordance with the provisions of Protocol 2 of the Universal Copyright Convention. All rights reserved. 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CONTENTS ENVIRONMENTAL HEALTH CRITERIA FOR BUTANOLS - FOUR ISOMERS: 1-BUTANOL, 2-BUTANOL, tert-BUTANOL, ISOBUTANOL INTRODUCTION 1-BUTANOL 2-BUTANOL tert-BUTANOL ISOBUTANOL REFERENCES WHO TASK GROUP MEETING ON ENVIRONMENTAL HEALTH CRITERIA FOR BUTANOLS - FOUR ISOMERS: 1-BUTANOL, 2-BUTANOL, tert-BUTANOL, ISOBUTANOL Members Dr B.B. Chatterjee, Calcutta, India Dr S. Dobson, Institute of Terrestrial Ecology, Monks Wood Experimental Station, Abbots Ripton, Huntingdon, United Kingdom (Rapporteur) Dr R. Drew, Department of Clinical Pharmacology, Flinders University of South Australia, Bedford Park, South Australia, Australia (Chairman) Dr M.-S. Galina Avilova, Institute of Occupational Hygiene and Professional Diseases, Moscow, USSR Dr A.A.E. Massoud, Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain-Shams University, Abbasia, Cairo, Egypt (Vice-Chairman) Dr A.N. Mohammed, University of Calabar, Calabar, Nigeria Page 2 of 75 Butanols - four isomers (EHC 65, 1987) Dr C.P. Sadarangani, Bader Al Mulla and Brothers, Safat, Kuwait Secretariat Ms B. Bender, International Register of Potentially Toxic Chemicals, United Nations Environment Programme, Geneva, Switzerland Dr K.W. Jager, International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland (Secretary) Ms F. Ouane, International Register of Potentially Toxic Chemicals, United Nations Environment Programme, Geneva, Switzerland NOTE TO READERS OF THE CRITERIA DOCUMENTS Every effort has been made to present information in the criteria documents as accurately as possible without unduly delaying their publication. In the interest of all users of the environmental health criteria documents, readers are kindly requested to communicate any errors that may have occurred to the Manager of the International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland, in order that they may be included in corrigenda, which will appear in subsequent volumes. * * * Detailed data profiles and legal files can be obtained from the International Register of Potentially Toxic Chemicals, Palais des Nations, 1211 Geneva 10, Switzerland (Telephone no. 988400 - 985850). ENVIRONMENTAL HEALTH CRITERIA FOR BUTANOLS - FOUR ISOMERS: 1-BUTANOL, 2-BUTANOL, tert-BUTANOL, ISOBUTANOL A WHO Task Group on Environmental Health Criteria for Butanols met in Geneva from 11 to 15 November 1985. Dr K.W. Jager opened the meeting on behalf of the Director-General. The Task Group reviewed and revised the draft criteria document and made an evaluation of the health risks of exposure to butanols. The first draft of this document was partially based on information contained in Toxicology Data Sheets made available by the Health, Safety and Environment Division of Shell Internationale Petroleum Maatschappij B.V., and on information obtained by a search of data bases by IRPTC. Additional information supplied by IPCS Participating Institutions was added to the second draft. The efforts of all who helped in the preparation and finalization of the document are gratefully acknowledged. * * * Partial financial support for the publication of this criteria document was kindly provided by the United States Department of Health and Human Services, through a contract from the National Institute of Environmental Health Sciences, Research Triangle Park, Page 3 of 75 Butanols - four isomers (EHC 65, 1987) North Carolina, USA - a WHO Collaborating Centre for Environmental Health Effects. The United Kingdom Department of Health and Social Security generously covered the costs of printing. INTRODUCTION The butanol isomers occur naturally as products of fermentation and are also synthesized from petrochemicals. They are used widely as solvents and intermediates in chemical industries. Human exposure to high concentrations of the butanol isomers will be primarily occupational while exposure to low concentrations will be mainly through foods in which they occur naturally or as flavouring agents. Apart from slight differences in the boiling point and water solubility, the physical properties of the isomers are similar. With only minor differences between isomers, the toxicity for aquatic organisms of all four butanols is low and none of the compounds shows any capacity for bioaccumulation. Apart from tert-butanol, all isomers are readily biodegradable and would be expected to be fully oxidised by microorganisms within a few days. The tert-butanol is metabolized more slowly and would be degraded within a few weeks. The likely background concentrations of all butanol isomers would not have any impact on the aquatic environment. In animals, the butanols are readily absorbed through the lungs and gastrointestinal tract. 1-Butanol, 2-butanol, and isobutanol are primarily metabolized by alcohol dehydrogenase and are rapidly eliminated from the blood. tert-Butanol is not a substrate for alcohol dehydrogenase and its elimination is slower than that of the other isomers. On the basis of oral LD50 values in the rat, the butanols can be classified as being slightly or practically non-toxic. In large amounts, all isomers have the ability to induce signs of alcoholic intoxication in both animals and man. Data regarding other biological effects in man and animals cannot be easily compared and symptoms and effects are covered in the separate sections for each isomer. On the basis of the available data, the Task Group did not expect any adverse effects from occupational exposure under conditions of good manufacturing practice. The Task Group considered that the available data were inadequate to give guidelines for the setting of occupational exposure limits for any of the butanol isomers. The effects of long-term exposure to low concentrations of the butanols could not be judged because of lack of information. The Task Group recommended that relevant studies should be conducted so that this could be achieved. ENVIRONMENTAL HEALTH CRITERIA FOR 1-BUTANOL Page 4 of 75 Butanols - four isomers (EHC 65, 1987) CONTENTS ENVIRONMENTAL HEALTH CRITERIA FOR 1-BUTANOL 1. SUMMARY 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 2.1 Identity 2.2 Physical and chemical properties 2.3 Analytical methods 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 6. KINETICS AND METABOLISM 7. EFFECTS ON ORGANISMS IN THE ENVIRONMENT 7.1 Aquatic organisms