International Module W501 Measurement of Hazardous Substances (including Risk Assessment) Day 1

1. International Module W501 Measurement of Hazardous Substances (including Risk Assessment) Day 1

2. Insert site Emergency procedures

3. Insert Lecturer(s) Background

4. Your Background? Two (2) minute overview of your background

5. Course Aims • To provide participants with a sound understanding of the techniques for assessing exposure to hazardous substances in the workplace • To understand how exposure information can be used to assess risk

6. Course Learning Outcomes • Participants will be able to: • Describe the general approach to occupational health risk assessment including role of atmospheric monitoring • Select the appropriate equipment to measure specific airborne contaminants & devise a suitable sampling strategy • Present the results in a useful form

7. What is Required to Complete this Course • Ask questions as we go through the notes • Participate in the case study discussions • Participate in the practical exercises • Attempt the questions each night

8. What is Occupational Hygiene ? 'Occupational Hygiene is the discipline of anticipating, recognising, evaluating and controlling health hazards in the working environment with the objective of protecting worker health and well-being and safeguarding the community at large.' (Source IOHA)

9. Topics to be Discussed • Basic physiology & toxicology • Risk assessment • Hygiene standards • Air sampling theory & practice • Biological monitoring • Sample analysis • Dusts, fumes & fibres • Vapours & gases • Presentation of results

10. Today’s Learning Outcomes • Physiology & toxicology • Understand and be aware of the features of the interacting systems of the human body • Understand the routes of contaminant entry into the human body and their target organs and systems • Understand the concept of dose response

11. Today’s Learning Outcomes (cont) • Risk Assessment • Understand principles & processes of risk assessment • Be able to apply these principles & processes in a workplace situation

12. Today’s Learning Outcomes (cont) • Hygiene standards • Understand the principles of setting hygiene standards • Understand the application and limitations of hygiene standards

13. Work Groups • Each participant will be assigned a work group for the duration of the course • The work groups are expected to work as a team when evaluating cases studies and undertaking practical sessions

14. Introduction to Physiology & Toxicology

15. Discussion Topics The Human Body Routes of Entry Target Organs & Systems Concept of Dose Response

16. The Human Body 12 Interacting systems: Cardiovascular Muscular Digestive Nervous Endocrine Reproductive Immune Respiratory Integumentary Skeletal Lymphatic Urinary

17. Cardiovascular System • Includes the heart, blood & the blood vessels (arteries, capillaries & veins) • Arteries bring oxygenated blood from heart to the tissues • Veins bring deoxygenated blood back to the heart

18. Digestive System • Takes in food, digests it & extracts energy & nutrients & expels the waste • Nutrients can be absorbed into blood & lymph systems • Some used for energy, some for building tissues & cells & some stored for future use

19. Endocrine System • Control system of glands which secrete chemical messengers or hormones • Endocrine glands release hormones directly into bloodstream of the body • Regulate metabolism, growth & sexual development

20. Immune System • Protects body from infection by creating & maintaining barriers to prevent that bacteria & viruses entering the body e.g. hepatitis, influenza, cholera, typhoid & malaria

21. Integumentary System • Comprises skin (cutaneous membrane) & hair, nails & endocrine glands • epidermis • dermis • subcutaneous tissue • Largest organ of body • interface with surroundings • Insulation & temp regulation

22. Lymphatic System • Major component of immune system • Complex system of lymphoid organs, lymph ducts & lymph vessels that produces & transport lymph fluid from tissues to circulatory system • Removal of excess fluids from body tissues • Absorption of fatty acids & transport of fat to circulatory system • Production of immune cells e.g. lymphocytes, monocytes & antibody producing plasma cells

23. Muscular System • Muscle attached to bone by tendons & other tissues • Exerts force by converting chemical energy into force • Nerves link muscle to CNS • Function • Produce movement • Maintain posture • Stabilise joints

24. Nervous System • Electrical impulses carried along nerve cells • CNS – body’s control centre • PNS – all other nerves & neurons • Somatic : • body’s movement & conscious control • Autonomic: • Sympathetic – responds to impending danger or stress • Parasympathetic – evident when resting relaxed

25. Reproductive System Produces offspring by fertilisation or fusion of a sperm and one ovum and the subsequent development of the offspring

26. Respiratory System • Responsible for carrying oxygen from inhaled air to the bloodstream & expelling the waste product of carbon dioxide

27. Skeletal System • 206 bones joined by ligaments & tendons • Protective & supportive framework for attached muscles & soft underlying tissues • Produces red & white blood cells in bone marrow • Bones store minerals eg calcium & can be transported elsewhere

28. Urinary System • The body’s filtering system via the kidneys which reabsorb approx 99% of the fluid into the blood • Waste or urine passed to the bladder for excretion

29. Routes of Entry • Inhalation • By far most common route of entry • Skin absorption • Via direct contact major source of entry of organics eg solvents and pesticides

30. Routes of Entry (cont) • Ingestion • Relatively minor route of accidental ingestion or poor personal hygiene • Eye • Direct entry point for some solvents and also at risk by direct contact

31. Target Organs & Systems Upon entry to the body contaminants can have an adverse effect on one or more organs (target organs) • Respiratory • Irritant & toxic gases eg Carbon monoxide & sulphur dioxide • Dusts & fibres eg silica & asbestos • Blood • Lead and mercury

32. Target Organs & Systems (cont) • Central Nervous System • Solvents eg toluene, xylene, MEK • Polycyclic and polyaromatic hydrocarbons • Liver • Alcohols & solvents • Kidneys • Selenium, alcohol & sodium compounds

33. Target Organs & Systems (cont) • Brain • Mercury - “as mad as a hatter” • Urinary • Biological agents • Some metals • Reproductive • Lead, organic mercury

34. Target Organs & Systems (cont) • Fatty tissues • Solvents • Skin • Acids, alkali • Epoxy resins • Skeletal • Lead • Benzene

35. Target Organs & Systems (cont) • Endocrine • Lead, cadmium • Carbon disulphide

36. Concept of Dose Response “No substance is a poison by itself, it is the dose that makes a substance a poison” Paracelsus 1540

37. Dose Effect Relationship • For each chemical there is a dose-effect relationship • Acute (immediate) effects (Irritants, CO) • Chronic (long-term) effects (Benzene, Asbestos) • Local effects occur at point of contact • Systemic effects occur at distant target organs

38. Dose Effect relationship (cont) • Factors effecting this relationship include • Physical state of the material • Concentration • Possible routes of entry to the body • Target organs

39. Dose Effect Relationship (cont) • Retention rate in the body • Human pre-disposition (pre-existing medical condition) • Individual sensitivity • Frequency & duration of exposure • Potency of compound • Synergistic effects with other compounds (e.g. asbestos & smoking)

40. Key Factors • Dose • Effect • Critical organ concentration

41. Dose The concentration of a substance at the site of effect (regard being made for the time which substance concentration is maintained) Dose = concentration x duration of exposure

42. Effect Any observable biological change associated with the contaminant concerned: • Should be quantifiable • Does not need to be an adverse observable effect • Certain effects can be beneficial and only become adverse if the dose is excessive or remains for a critical period of time

43. Critical Organ Concentration That concentration beyond which organs exhibit some effect • May not be organ of concentration (eg bone accumulates lead but critical organ is bone marrow)

44. Target Organs • Respiratory system • Skin • Eyes • Blood • Liver • Kidneys • Bladder • Nervous system

45. Dose Effect v Dose Response • Dose effect: Correlation between dose and the magnitude of effect • Dose response: Correlation between response of an organ with estimates of dose

46. Threshold • The dividing line between no-effect and effect levels of exposure • For each substance there is a threshold of intoxication which is usually different for individual substances

47. Dose Response Curve Source: Tranter 1999 –Reproduced with permission Dose Response Curve

48. Threshold of Intoxication • For each substance, no matter how toxic, there exists a dose level called the threshold of intoxication, which the human body is capable of accepting and detoxifying without injury to itself

49. Individual Susceptibility Source: AIOH 2007-Reproduced with permission

50. Risk Assessment