Published on March 5, 2008
Physical Hazards Noise, Radiation, and Ergonomics: Physical Hazards Noise, Radiation, and Ergonomics NOISE AND ITS EFFECT ON HEARING: NOISE AND ITS EFFECT ON HEARING Introduction: Introduction Definitions Biological Process of Hearing Two Types of Hearing Loss Conductive Hearing Loss Sensory Hearing Loss Regulatory Levels Audiometric Testing Measuring Noise Definitions: 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 Biological Process of Hearing: 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 Biological Processes of Hearing: 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. Two Types of Hearing Loss: Two Types of Hearing Loss Conductive Sensory Conductive Hearing Loss: 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 Sensory Hearing Loss : 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 Sensory Hearing Loss: Sensory Hearing Loss Cannot be corrected medically or surgically Hearing loss in the workplace is typically a sensory hearing loss Regulatory Levels: 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 Audiometric Testing: 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 Measuring Noise: 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 Types of Hearing Protection Devices: Types of Hearing Protection Devices Foam earplugs Earmuffs Noise Reduction Rating ( NRR ) Plugs + Muffs Take the higher NRR and add 5 dB to it NRR - Noise Reduction Rating: 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% Earplugs: 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 Earmuffs: 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 Inserting foam earplugs properly:: 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 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 Hearing Protection Caring for Hearing Protection Devices: 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. IONIZING RADIATION: IONIZING RADIATION OBJECTIVES: OBJECTIVES Ionizing Radiation Characteristics Radiological Response Biological Consequences / Health Effects Regulations/Standards Radiation Protection/Controls Instrumentation Types of radiation IONIZING RADIATION DEFINITIONS: 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. RADIOLOGICAL RESPONSE: RADIOLOGICAL RESPONSE Spills of Radioactive Material Stop the spill, Warn others of the spill, Isolate the area and Minimize exposure to radiation IONIZING RADIATION CHARACTERISTICS: 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 IONIZING RADIATION CHARACTERISTICS: IONIZING RADIATION CHARACTERISTICS Alpha Radiation () Physical Characteristics (Helium w/o electrons) Weak penetrating power Cannot penetrate a sheet of paper Internal Hazards IONIZING RADIATION CHARACTERISTICS: IONIZING RADIATION CHARACTERISTICS Beta Radiation () Physical Characteristics (electron) External Exposure Skin Damage = “Beta burn” Method of Ionization Annihilation Radiation IONIZING RADIATION CHARACTERISTICS: 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. IONIZING RADIATION CHARACTERISTICS: 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. IONIZING RADIATION CHARACTERISTICS: 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 SOURCES OF EXPOSURE: 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) SOURCES OF EXPOSURE: 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.) SOURCES OF EXPOSURE: 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. BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS: 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. BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS: BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS Acute Effects: Acute Radiation Syndrome (ARS) Only seen after whole-body exposures above 100 rad REGULATIONS/STANDARDS: REGULATIONS/STANDARDS Worker Limits - Adults Only: Radiation workers (Fed & State) = 5 rem/year Total Effective Dose = 5 rem/year TYPES OF RADIATION: 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 RADIATION PROTECTION/CONTROLS: 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. RADIATION PROTECTION/CONTROLS: 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 RADIATION PROTECTION/CONTROLS: 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. INSTRUMENTATION: INSTRUMENTATION Example: Ludlum 3 (, , and ) INSTRUMENTATION: INSTRUMENTATION Example: Ludlum 19 ( and x-ray) INSTRUMENTATION: INSTRUMENTATION Example: SAIC Dosimeters () REGULATORY AGENCIES: 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 Ergonomics: Ergonomics A quick overview Ergonomics: Ergonomics The study of interactions between humans and their working environment Repetitive motion is one branch Ergonomics: 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 Ergonomics: 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 Ergonomics: 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 Ergonomics: 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 QUESTIONS?: QUESTIONS?