UNEP/IPCS Training Module No. 3 CHEMICAL RISK ASSESSMENT HUMAN RISK ASSESSMENT, ENVIRONMENTAL PJSK ASSESSMENT AND ECOLOGICAL RISK ASSESSMENT 1999 The views expressed in documents by named authors are solely the responsibility of those authors. Produced under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation and the World Health Organization, and within the framework of the Inter-Organization Programme for the Sound Management of Chemicals The International Programme on Chemical Safety (IPCS), established in 1980, is a joint venture of the United Nations Enviromnent Prograrmne (UNEP), the International Labour Organisation (ILO), and the World Health Organization (WHO). The overall objectives of the IPCS are to establish the scientific basis for assessing the risk to human health and the environment from exposure to chemicals, through international peer-review processes, as a prerequisite for the promotion of chemical safety, and to provide technical assistance in strengthening national capacities for the sound management of chemicals. The Inter-Organization Programme for the Sound Management of Chemicals (IQMC) was established in 1995 by UNEP, ILO, the Food and Agriculture Organization of the United Nations, WHO, the United Nations Industrial Develop- ment Organization, and the Organisation for Economic Co- operation and Development (Participating Organizations), following recommendations made by the 1992 United Nations Conference on Environment and Development to strengthen cooperation and increase coordination in the field of chemical safety. The purpose of the IOMC is to promote coordination of the policies and activities pursued by the Participating Organizations, jointly or separately, to achieve the sound management of chemicals in relation to human health and the environment. I' ACKNOWLEDGEMENT The International Programme on Chemical Safely (IPCS) is a joint venture of the United Nations Environment Programme (UNEP), the Jnternational Labour Organisation (ILO) and the World Health Organization (WHO). Amongst its many activities are training programmes on risk assessment and risk management of chemicals for which a series of Training Modules is being developed. This Training Module on Risk Assessment was prepared by Dr J.H. Duffus and Dr M.V. Park, The Edinburgh Centre for Toxicology, Edinburgh, U.K. The technical development, field testing, editing and publication of the Module has been coordinated by UNEP Chemicals (TRPTC), Geneva, Switzerland, as [JNEP's contribution to the training activities being conducted by the IPCS. No language editing of the Module has been conducted, by the IPCS Central Unit. The draft Training Module was tested at a series of IPCS Training Courses on Toxic Chemicals, Environment and Health - Dhaka, Bangladesh, March 1997; Bandung, Indonesia, May 1997; Colombo, Sri Lanka, July 1997; Islamabad, Pakistan, October 1997; Mukono, Uganda, March 1998; Harare, Zimbabwe, March 1998; Montevideo, Uruguay, November 1998; Buenos Aires, Argentina, November 1998 - with fmancial support from the Government of the Kingdom of the Netherlands, and at two workshops, namely: the National Workshop on Chemical Risk Assessment, Moscow (Golitsino), Russian Federation, October 1997; and the Subregional Workshop on Chemical Risk Assessment, Bratislava (Senec). Slovakia, November 1997. Funds were provided by the Government of the Russian Federation and the Government of Austria. The IPCS gratefully acknowledges the work undertaken by the authors, Dr Duffus and Dr Park, and by IINEP, and thanks all who helped in the preparation and finalization of this book for their efforts. Financial support for the publication was provided by the Netherlands Ministry of Development and Cooperation under the auspices of the IPCS Project on National Training Activities for Developing Countries on Toxic Chemicals, Environment and Health. 111 Contents Section A: Human Risk Assessment Section B: Environmental Risk Assessment 107 Section C: Ecological Risk Assessment 177 iv UNEP/IPCS Training Module No. 3 Section A Human Risk Assessment 3.3.2.5 Differences in approach between the occupational and the non-occupational situation ------------------------------ 26 3.3.3 Benchmark Dose ................................................................. 27 3.3.4 Non-Threshold Effects ........................................................ 28 3.3.4.1 Quantitative extrapolation...................................... 28 3.3.4.2 Ranking of potencies ............................................. 30 3.3.4.3 Modification of the highest "no effect" level........... 30 3.4 Exposure assessment....................................................................... 30 3.4.1 General aspects.................................................................. 30 3.4.1.1 Introduction............................................................ 30 3.4.1.2 Types of exposure................................................. 32 3.4.1.3 Modelling ............................................................... 33 3.4.2 Occupational Exposure....................................................... 35 3.4.2.1 Introduction............................................................ 35 3.4.2.2 Inhalation exposure ......... ___ ............................... 36 3.4.2.3 Dermal exposure................................................... 37 3.4.2.4 Measurement of exposure.......................................38 3.4.3 Consumer exposure............................................................ 41 3.4.4 Indirect exposure via the environment ................................ 42 3.5 Risk characterisation ......................................................................... 42 3.5.1 General principles for assessing risk to human health........ 42 3.5.2 Guidance or Guideline Values ............................................ 44 3.5.3 Semi-quantitative assessment of risk from chemicals in the workplace............................................................................ 45 4 Control of risk ................................................................................................. 46 4.1 Modification of process conditions .................................................... 47 4.1.1 Elimination and substitution ................................................ 47 4.1.2 Containment and ventilation................................................ 47 4.1.2.1 Complete enclosure with exhaust ventilation ......... 48 4.1.2.2 Partial enclosure with exhaust ventilation............... 48 4.1.2.3 Local exhaust ventilation (LEV)..............................48 4.1.3 Open working......................................................................49 4.1.4 Personal protective equipment............................................ 49 4.1.4.1 Respiratory protective equipment (RPE) ................ 49 4.2 Fire and explosion ............................................................................ 50 4.3 Emergency planning......................................................................... 50 5 Conclusion...................................................................................................... 51 6 Bibliography.................................................................................................... 52 2 7 Self Assessment Exercises . 54 ANNEX 1, Animal toxicity testing of chemicals................................................. 57 ANNEX 2. Risk Phrases ................................................................................... 62 ANNEX 3. Safety Phrases ................................................................................ 67 ANNEX 4. Toxicological classification and labelling of dangerous substances 71 ANNEX 5. Estimation of the tolerable intake of a chlorinated hydrocarbon fromtoxicity data ............................................................................. 78 ANNEX 6. Extrapolations between species of the effects of substances taken bytheoral route .................. ................. ............................................ 80 ANNEX 7. Modelling of airborne concentrations of volatile liquids in the workplace........................................................................................ 83 ANNEX 8. Case study: contamination of room with metallic mercury .............. 85 ANNEX 9. Exposure-route models ................................................................... 87 ANNEX 10. Biomarkers ...................................................................................... 89 ANNEX 11. An example on the development of guidance values...................... 91 3 UNEPIIPCS TRAINING MODULE SECTION A Human Risk Assessment EDUCATIONAL OBJECTIVES You should know the difference in meaning of the terms "hazard" and "risk" and the four stages of risk assessment. You should know the commonest routes by which substances are absorbed into the body and be able to differentiate between: acute and chronic effects, local and systemic effects, and reversible and irreversible effects. You should be familiar with the problems in extrapolating the results of studies of the harmful effects of substances from animals to humans and know what are the main sources of hazard information on commercially available substances. You should understand the difference between stochastic and deterministic (or non- stochastic) effects and know how can one assess the relative toxicities of substances postulated to have no threshold level. You should be aware of how exposure standards are