Environmental Health Criteria 2 Polychlorinatec' biphenyls I and terphenyls Executive Summary Issued by the World Health Organization in conjunction with the United Nations Environment Programme NOTE TO THE READER In response to a number of World Health Assembly resolutions, and taking into consideration the recommendations of the United Nations Conference on the Human Environment held in Stockholm in 1972, and of the Governing Council of the United Nations Environment Programme (UNEP), an integrated and expanded programme on the assessment of the health effects of environmental pollution was initiated in 1973. The programme, known as the WHO Environmental Health Criteria Pro- gramme, is implemented with the support of the Environment Fund of UNEP. In 1980, the Environmental Health Criteria Programme was incorporated into the more comprehensive International Programme on Chemical Safety (IPCS), jointly spon- sored by the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization. The results of the programme are a series of criteria documents. Each criteria document comprises an extensive scientific review concerning a specific environmental pollutant or group of pollutants, with information ranging from sources and exposure levels to a detailed account of the available evidence concerning their effects on human health. Drafts of these documents are prepared for WHO by indi- vidual experts or national institutions. They are then extensively reviewed by the approximately 25 Member States participating in this Programme and by one or more international groups of experts (task groups). A major objective of this programme is to assess existing information on the relationship between exposure to environmental pollutants (or other physical and chemical factors) and man's health and to provide guidelines for setting exposure limits consistent with the protection of public health. To facilitate the application of these guidelines in national environmental protection programmes, WHO decided to prepare "executive summaries" highlighting the infor- mation contained in the documents for those who need to know the health issues at hand, but not the scientific details. The executive summaries contain the exposure guidelines specified in the criteria documents as developed by the task group, together with the major supporting infor- mation on health effects. Every effort has been made not to deviate from the infor- mation presented in the criteria documents themselves. For some criteria documents, particularly those published three or four years ago, this means that any new data published since the meetings of the task groups have not been included. Such infor - mation will be considered when the criteria documents and the summaries are reviewed and revised. It would be appreciated if the reader would draw the attention of WHO to any diffi- culties encountered in using the information contained in the summary documents. Comments regarding this document should be addressed to: Division of En\ironmental Health, World Health Organization, 1211 Geneva 27, Switzerland Prinied in Switzerland 81 /.I - Otoor-Luder - 10,000 This report contains the collectwe views of an inter- narional group of experts and does not necessari'y represent the decisions or the stated policy of either the World Health Organization or the United Nations Environment Programme Environmental Health Criteria 2 POLYCHLORINATED BIPHENYLS AND TERPHENYLS Published tmder the joint sponsorship of the United Nations Environment Programme and the World Health Organization - sp 4 V World Health Organization —'-z- Qeneva, 1976 ISBN 92 4 154062 1 ) World Health Organization 1976 Publications of the World Health Organization enjoy copyright protection in accord- ance with the provisions of Protocol 2 of the Universal Copyright Convention. For rights of reproduction or translation of WHO publications, in part or in into, application should be made to the Office of Publications, World Health Organization, Geneva, Switzer - land. The World Health Organization welcomes such applications. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in pre- fererice to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. PRINTED IN UNITED KINGDOM POLYCHLORINATED BIPIJENYLS AND TERPHENYLS * Introduction Polychlorinated hi phenyls (PCBs) and polychlorinated terphenyls (PCTs) are complex organic chemicals used widely for their insu- lating properties. They are liquids of various densities containing chlorine, hydrogen and carbon and resemble mineral oils in appear- ance and consistency. They are not naturally occurring and are classi- fied as synthetic oils. PCBs and PCTs have been manufactured since 1930, production reaching a peak in 1970. As the evidence linking PCBs with harm to wildlife and disease in man accumulated, the production and use of PCBs were restricted or eliminated in several industrialized countries; other Countries are considering similar steps. However, this is only a partial solution because these com- pounds continue to persist in the environment and to accumulate in human body tissue. Characteristics PCBs and PCTs are manufactured and used in the form of mix- tures rather than as individual chemical compounds. The formu- lation of a mixture depends on the desired physical characteristics, such as density and texture. Because precise chemical formulation and purity are not usually necessary, mixtures may vary and im- purities may be present. Some of these impurities are thought to be similar to, yet possibly more toxic than, the compounds themselves. In addition to their durability, these compounds are nonflam- mable, difficult to vaporize, and remain stable at high tempera- tures, and are thus excellent insulators. They are mainly used in the production of electrical equipment, including transformers and capacitors, and as ingredients in heat exchange units, hydraulic *Summary of Polychiorinaled hiphenyls and terphenyls. Geneva, World Health Organization, 1976 (Environmental Health Criteria No. 2), 85 page.. fluids, lubricants, plasticizers, surface coatings, adhesive printing inks, pesticide extenders, etc. The uses of PCBs and PCTs can be divided into three categories: (a) controllable closed systems (transformers and capacitors); (b) uncon- trollable closed systems (heat exchangers and hydraulic systems); and (c) dissipative media (lubricants, plasticizers, adhesives, etc.). Nor- mally, leakages do not occur from properly designed transformers and capacitors but some loss into the environment can occur from heat exchangers and hydraulic systems. PCBs present in lubricants, plastici- zers, adhesives, etc. can be readily lost into the environment. However, environmental pollution with PCBs and PCTs mainly occurs because of the leakage and disposal of industrial fluids and through vaporiza- tion during the incineration of waste materials. 3. Environmental concentrations The presence of PCBs in the environment is extremely widespread; they have been found in the ambient air, water, soil and sediments, and in human and animal tissue in almost all parts of the world. Concentrations of up to 0.05 ttglml of air (0.05 ppm) have been observed. Unpolluted fresh water generally contains very low levels of PCBs (less than 0.0005 ig/l) compared with 0.05 Ig/l in moder- ately polluted rivers and 0.5 ig/l in heavily polluted rivers. Levels are usually higher in the sediments of polluted waters, since PCBs are only slightly soluble in water. Most soils contain PCB levels of less than 15 Lg/kg, but soils around factories producing electrical com- ponents have been found to contain as much as 510 mg/kg. It has been estimated that man's average daily intake of PCBs from the air and from drinking-water is less than 1 i g from each of these sources. The main exposure pathway of PCBs for the general population is through food. Vegetable and fruits generally have less than detectable I rg = 1 microgram = one millionth of a gram I mg = 1 milligram = one thousandth of a gram I ppm = I volume of a stated substance in I million volume units of another substance or mixture of substances - air in this case. levels, but some exceptions have been noted in crops irrigated with contaminated water, and in some foods packaged in contaminated material. PCBs in feed consumed by animals are readily absorbed by the organism and are mainly deposited in fatty tissues where they may be stored for long periods; high levels may accumulate, even when the daily intake is quite low. For this reason, fatty foods such as milk, butter, cheese, eggs, and meat are the main dietary sources of PCBs. Fish can also be a major source, particularly those taken from contaminated waters. In the industrialized countries, the average daily intake from food, including fish, is rarely less than 5.0 f.tg or greater than 100.0 tg (approximately 1 pg/kg body weight) per day. PCBs accumulate in human tissues just as they do in