Physical Hazards Noise, Radiation, and Ergonomics

1. Physical Hazards Noise, Radiation, and Ergonomics

2. NOISE AND ITS EFFECT ON HEARING

3. Introduction • Definitions • Biological Process of Hearing • Two Types of Hearing Loss • Conductive Hearing Loss • Sensory Hearing Loss • Regulatory Levels • Audiometric Testing • Measuring Noise

4. Definitions • Sound: • Composed of Frequency and Intensity • Frequency or pitch: • Hertz (Hz) • Intensity or loudness: • Decibels (dBA) • A doubling of the level of sound is perceived as less than double • Do not trust your ears

5. Biological Process of Hearing • Outer ear collects sound energy (pressure waves) • Sound travels down the ear canal to the eardrum • Sound waves set the eardrum in motion

6. Biological Processes of Hearing • Inside the cochlea, hair cells bend as waves pass by sending pulses via the auditory nerve to the brain. • Sound energy is converted from mechanical vibrations to fluid waves to electrical pulses.

7. Two Types of Hearing Loss • Conductive • Sensory

8. Conductive Hearing Loss • Caused by damage to or a malfunction of the outer and middle ear • Some causes • excessive ear wax • fluid in the ear • a torn eardrum • Colds • Usually hearing is restored once the cause is diagnosed and treated

9. Sensory Hearing Loss • Caused by damage to or a malfunction of the inner ear, auditory nerve, or the brain • Causes of sensory hearing loss • Aging, Damage to fetus, Hereditary, Noise, Disease, Injury, Drugs

10. Sensory Hearing Loss • Cannot be corrected medically or surgically • Hearing loss in the workplace is typically a sensory hearing loss

11. Regulatory Levels • Continuous noise • 85 dBA, 8 hour TWA - Action Level • hearing conservation program • training • medical monitoring • 90 dBA, 8 hour TWA - Permissible Exposure Level (PEL) • Wear Ear Plugs • Impact noise- no exposures above 140 dB shall be permitted

12. Audiometric Testing • Audiogram • Measures how loud a sound has to be before you can hear it • Comparing current to previous audiograms • Shows if hearing loss has occurred and at which frequencies

13. Measuring Noise • Sound Level Meter - Instant reading • grab sample • Quest 215 • Dosimeter - TWA • noise exposure is integrated over time • Quest 7 B • Du Pont MK 1, 2, 3

14. Types of Hearing Protection Devices • Foam earplugs • Earmuffs • Noise Reduction Rating ( NRR ) • Plugs + Muffs • Take the higher NRR and add 5 dB to it

15. NRR - Noise Reduction Rating • NRR and choosing an ear plug: Earmuff’s NRR - Subtract 25% Foam/expanding ear plugs - Subtract 50% All other plugs - Subtract 75%

16. Earplugs • Advantages: • small and lightweight • comfortable in hot environments • easily used with other safety equipment • Disadvantages: • may become loose and require occasional refitting • frequently soiled

17. Earmuffs • Advantages: • fits better for longer periods of time • Disadvantages: • may fit tight on your head • uncomfortable in warm environments • effectiveness is limited to the quality of the seal around your ear

18. Inserting foam earplugs properly: • Reach around back of your head • Gently pull your ear back and up • Roll the plug into a small diameter • Insert the plug well into the ear canal • Hold the plug in place for a few seconds while it expands and forms a good seal

19. Hearing Protection • Make sure that the earmuffs fit snugly around your ears • Use earplugs if you wear glasses, earrings, or have facial hair which prevent the earmuffs from forming a good seal

20. Caring for Hearing Protection Devices • Foam Earplugs: • store them in a clean, cool, dry place • if earplugs become soiled, torn, or stiff, discard them and get a new pair • Earmuffs: • store them in a clean, cool, dry place • inspect your earmuffs for cracks around the foam cups.

21. IONIZING RADIATION

22. OBJECTIVES • Ionizing Radiation Characteristics • Radiological Response • Biological Consequences / Health Effects • Regulations/Standards • Radiation Protection/Controls • Instrumentation • Types of radiation

23. IONIZING RADIATION DEFINITIONS • Ionizing Radiation (IR) - Any particles or rays given off (radiate) from a source that produces ionization • Ionization - When atoms or molecules become charged - unbalanced electron proton ratio. • Radiation - Refers to the way particles & rays radiate from their source at speeds up to that of light.

24. RADIOLOGICAL RESPONSE • Spills of Radioactive Material • Stop the spill, • Warn others of the spill, • Isolate the area and • Minimize exposure to radiation

25. IONIZING RADIATION CHARACTERISTICS • Common Types of IR • Alpha • Beta • Gamma • X-rays • Types of Non-IR • Radiowaves & Microwaves • Infrared Light • Visible Light • Ultrasound • UV Light

26. IONIZING RADIATION CHARACTERISTICS • Alpha Radiation () • Physical Characteristics (Helium w/o electrons) • Weak penetrating power • Cannot penetrate a sheet of paper • Internal Hazards

27. IONIZING RADIATION CHARACTERISTICS • Beta Radiation () • Physical Characteristics (electron) • External Exposure • Skin Damage = “Beta burn” • Method of Ionization • Annihilation Radiation

28. IONIZING RADIATION CHARACTERISTICS • Gamma Radiation () • Indirectly ionizing radiation (electromagnetic ray - e.g. light) • Energy bundles - have no charge or mass • Travels much farther than  or  radiation • Can pass through a body without hitting anything or give an atom all or part of its energy.

29. IONIZING RADIATION CHARACTERISTICS • Units • Rad: Absorbed dose equal to 0.01 Joule/kg in any substance. • Rem: Conventional unit for dose equivalent. • The dose equivalent in rem is equal to the absorbed dose in rad multiplied by the quality factor.

30. IONIZING RADIATION CHARACTERISTICS • Radiation dose is expressed in rads • For  and  radiation, 1 rad = 1 rem • For  radiation, 1 rad = 20 rem Rem = (Rad)(QF) Quality Factor (QF) for:  and  = 1 =20

31. SOURCES OF EXPOSURE • Natural Sources (81%) • 55% - Radon • 8% - Cosmic • 8% - Terrestrial (coal, crude oil & natural gas, phosphate rock products, sand, hot springs & caves) • 10% - Food & Water (i.e., Potassium-40)

32. SOURCES OF EXPOSURE • Man-made Sources (19%) • 11% - Medical X-ray (-rays) • 4% - Nuclear Medical Exposures • 3% - Consumer Products • <1% - Other Sources (occupational sources, nuclear fallout, nuclear fall cycle radioactive waste, hospital radioactive waste, radioactively contaminated sites, etc.)

33. SOURCES OF EXPOSURE • For the U.S. population, average annual total effective dose (natural & anthropogenic) is approximately 360 mrem (0.360 rem). • For the general public, the exposure limit is 0.1 rem/year or 2 mrem/hr.

34. BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS • DNA is the primary target • Radiation can produce free radicals elsewhere in the body that then reacts with DNA • DNA damage is cumulative • Cells are most sensitive to radiation damage if • Have a high mitotic (cell division) rate • A slow (long) mitotic cycle • Undifferentiated stem cells • Exposure to the eyes causes cataract formation.

35. BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS • Acute Effects: Acute Radiation Syndrome (ARS) • Only seen after whole-body exposures above 100 rad

36. REGULATIONS/STANDARDS • Worker Limits - Adults Only: • Radiation workers (Fed & State) = 5 rem/year • Total Effective Dose = 5 rem/year

37. TYPES OF RADIATION Alpha • U-238, Pu-238, Pu-239, Ra-226, Po-210, Am-241 • Beta • H-3, C-14, S-35, Pu-241 (low-energy) • P-32, Sr-90, I-131 (medium to high energy) • Also includes partial gamma (I-131) • Other Gamma (Cs-137, Co-60, Ir-192

38. RADIATION PROTECTION/CONTROLS • Time: • Exposure increases linearly with an increase in the amount of time spent. • Reduce the time of exposure to a minimum • ALARA (as low as reasonably achievable) • Shielding: • Lead and concrete - absorbs the radiation.

39. RADIATION PROTECTION/CONTROLS • Distance: • Dose rate is inversely proportional to the distance squared from the source. I1 = I2(D2/D1)2 where: I1 = is the intensity at a distance D1, and I2 = is the intensity at a distance D2

40. RADIATION PROTECTION/CONTROLS • PPE: • Prevent contamination of particles on the surface of the skin • The use of shield layers such as eye shield and gloves - prevents particles from depositing on the body and shields by absorption.

41. INSTRUMENTATION Example: Ludlum 3 (, , and )

42. INSTRUMENTATION Example: Ludlum 19 ( and x-ray)

43. INSTRUMENTATION Example: SAIC Dosimeters ()

44. REGULATORY AGENCIES • California Dept. of Health Services, Radiation Branch: State Regulatory • Nuclear Regulatory Commission (NRC) • Regulates nuclear power plant operations • Regulates the use of radioactive material in research and medical applications • NRC regulations apply to all types of ionizing radiation (IR) • Sets limits on the total dose of IR above background

45. Ergonomics • A quick overview

46. Ergonomics • The study of interactions between humans and their working environment • Repetitive motion is one branch

47. Ergonomics • Examples: • Carpal tunnel syndrome - compressed median nerve due to swelling of the tendon sheath • Prolonged flexing of the wrist - typing • Tendentious - inflamed tendons due to stress • Excess motion or stress - frayed, bumpy thick tendon • White Finger - loss of adequate blood supply to fingers • Vibrations, very tight gripping - Jack hammer • Lower back pain - back stresses especially poor lifting • Bent back, twisting motion, excess weight

48. Ergonomics • Lifting, protect the back! • Keep back straight • Forced to lift with legs • Exponential increases with “leaning over” to pick up • Pivot point, lower back • Think, do not use jerky rapid motion • Do not twist • Do not raise above shoulders

49. Ergonomics • Tools, protect the hand (wrist) • Keep writs straight with respect to the arm, no bending • Encircled tool should not allow fingers to touch palm • Vary tasks, avoid doing something repetitively without breaks • Keep shoulder relaxed and elbow at the side of the body

50. Ergonomics • Universal Key Points • Avoid sustained repetitive motions • Flex joints minimally • Work between shoulder and elbow height • Use good illumination • Do only what is comfortable, not pushing to the limits • Use good posture