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Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
Prof. David Coggon: Environmental health hazards
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Prof. David Coggon: Environmental health hazards

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PowerPoint presentation that Prof. David Coggon of University of Southampton gave to the Isle of Wight branch of Cafe Scientifique on 10 October 2011

PowerPoint presentation that Prof. David Coggon of University of Southampton gave to the Isle of Wight branch of Cafe Scientifique on 10 October 2011

Published in: Health & Medicine, Technology
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Transcript

  • 1. CHEMICAL AND PHYSICALHAZARDS IN THE ENVIRONMENT David Coggon 1
  • 2. “People move to the countryside thinking it will be ahealthy environment to bring up their children and do notknow about the dangers and risks inherent in the sprayingof poisonous chemicals on surrounding fields, until theythemselves suffer adverse effects on their health” Georgina Downs (pesticides campaigner) 2
  • 3. MINIMATA DISEASE 5
  • 4. BHOPAL 6
  • 5. “With a third of all the food we eatcontaining them, pesticide residueshave become a routine ingredient inour diet. Something needs tochange.” Guardian 20.10.01
  • 6. HAZARDA hazard is a potential harmful effectof exposure to an agent, activity orstressor
  • 7. RISKRisk is the probability that a hazard willbe realised, given the circumstances ofexposure to an agent, activity orstressor
  • 8. Risk depends importantly onthe circumstances and extentof exposure 10
  • 9. QUANTIFICATION OF RISK • Relative risk • Attributable risk • Population attributable risk
  • 10. RISK AND UNCERTAINTY• Risks in individuals correspond to rates in populations• Risk estimates are subject to uncertainty because of incomplete scientific information• Unlike risk, uncertainty cannot be quantified empirically. It can only be characterised in terms of subjective beliefs. 14
  • 11. ASSESSING RISK• Extrapolation from existing scientific knowledge• Laboratory experiments in vitro and in vivo• Epidemiology• Experimental studies in humans
  • 12. RISK MANAGEMENT• Weighs risks and costs against benefits, taking account of uncertainties• Depends on value judgements
  • 13. THE PRECAUTIONARY PRINCIPLE“Where there are threats of serious orirreversible damage, lack of full scientificcertainty shall not be used as a reason forpostponing cost-effective measures toprevent environmental degradation.” UN Conference on Environment and Development 1992
  • 14. AIM OF PESTICIDE REGULATIONResidues of plant protection productsconsequent on application consistent withgood plant protection practice must nothave any harmful effects on human oranimal health 18
  • 15. METHOD OF RISK ASSESSMENT• Reasonable upper estimates of daily exposure are compared with appropriate toxicological reference values derived principally from animal studies• Tiered approach with assessment factors to allow for uncertainty 19
  • 16. MAIN SOURCES OF UNCERTAINTY• Extrapolation from animals to humans• Variation between individuals• Exposure modelling• Statistical uncertainties in underpinning data• Aggregated and cumulative exposures 20
  • 17. “The government allows thephone industry to focuspulse-modulated microwavebeams, pass them throughour homes – and slow-cookus day and night. We are inthe microwave oven againstour will – and it is switchedon.” 21
  • 18. MOBILE PHONES – THE CHALLENGE • New technology rapidly introduced on massive scale • Continually evolving 22
  • 19. APPROACH TO RISK ASSESSMENT• Heating of tissues is the only established hazard. Exposure-response is well- understood.• Seek evidence of other possible hazards from biophysics, in vitro and in vivo toxicology, human experiments and observational epidemiology 23
  • 20. MAIN SOURCES OF UNCERTAINTY• In vitro and animal models less developed and less standardised• Exposure characterisation• Bias, confounding and statistical uncertainty 24
  • 21. NOCEBO EFFECTSAdverse health effects, sometimeswith physical manifestations, that arisethrough psychological mechanisms 25
  • 22. EVIDENCE FOR NOCEBO EFFECTS• Patterns of illness do not fit with known toxicological mechanisms of disease• Psychological characteristics and health beliefs predict later illness• Double-blind randomised experiments 26
  • 23. 27

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