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Unit 2-industrial-toxicology


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Unit 2-industrial-toxicology

  3. 3. <ul><li>Toxicity – the degree a substance can harm humans, animals, or environment </li></ul><ul><li>Hazard – is something that has the potential to cause harm if exposed to a certain set of circumstances </li></ul><ul><li>Risk – is the probability that harm (i.e. adverse effect) will occur given exposure </li></ul>TOXICITY VS. HAZARD
  4. 4. <ul><li>Characteristics of hazard: </li></ul><ul><ul><li>Route of exposure </li></ul></ul><ul><ul><li>Form </li></ul></ul><ul><ul><li>Dose/concentration </li></ul></ul><ul><ul><li>Absorption rate </li></ul></ul><ul><ul><li>Exposure duration </li></ul></ul><ul><ul><li>Surface area exposed </li></ul></ul><ul><ul><li>Area exposed (ex. skin thickness) </li></ul></ul><ul><li>How hazard reacts within the body </li></ul><ul><ul><li>Distribution </li></ul></ul><ul><ul><li>Metabolism </li></ul></ul><ul><ul><li>Excretion </li></ul></ul><ul><ul><li>Other exposures (i.e. mixtures) </li></ul></ul>FACTORS AFFECTING TOXICITY AND RISK
  5. 5. <ul><li>Independent effects </li></ul><ul><ul><li>Occurs when the hazards are different in composition and act in a different manner and on different organ systems </li></ul></ul><ul><li>Additive effects </li></ul><ul><ul><li>The total effect is the sum of each independent effect </li></ul></ul><ul><ul><li>Occurs when the hazards act in a similar way and produce the same effect </li></ul></ul><ul><ul><li>Example: Chlorinated insecticides and halogenated solvents  liver toxicity.   </li></ul></ul><ul><li>Potentiated effects </li></ul><ul><ul><li>When a substance causes an increase in harm that on its own does not elicit an effect </li></ul></ul><ul><ul><li>Example: CO potentiates noise induced hearing loss from exposure to noise </li></ul></ul><ul><li>Synergistic effects </li></ul><ul><ul><li>Is an interaction where one hazard exacerbates the adverse effect of another. </li></ul></ul><ul><ul><li>Example: asbestos exposure and smoking  lung cancer </li></ul></ul><ul><li>Antagonistic effects </li></ul><ul><ul><li>The effect of one substance cancels or reduce the effect of another </li></ul></ul><ul><ul><li>Often related to enzyme function and metabolism </li></ul></ul><ul><ul><li>Example: ethanol reduces effects of methanol exposure </li></ul></ul>MULTIPLE EXPOSURES
  6. 6. <ul><li>How do we adjust for these when determining compliance or health risk? </li></ul><ul><ul><li>Independent effects </li></ul></ul><ul><ul><ul><li>Use TLVs as normal </li></ul></ul></ul><ul><ul><li>Additive effects </li></ul></ul><ul><ul><ul><li>Calculate TWA for mixtures (located in your text book) </li></ul></ul></ul><ul><ul><li>Antagonistic effects </li></ul></ul><ul><ul><ul><li>Use TLVs as normal </li></ul></ul></ul><ul><ul><ul><li>Has reduced effects but don’t know to what level so take conservative approach </li></ul></ul></ul><ul><ul><li>Potentiated/ synergistic effects </li></ul></ul><ul><ul><ul><li>There is no clear method </li></ul></ul></ul><ul><ul><ul><li>Indicates we must take extreme caution! </li></ul></ul></ul>MULTIPLE EXPOSURES II
  7. 7. <ul><li>TLV designation </li></ul><ul><li>Indicates that skin exposure may be a significant contributor to overall dose </li></ul><ul><li>Determined by: </li></ul><ul><ul><li>Studies showing significant absorption through skin or systemic effects </li></ul></ul><ul><ul><li>Low dermal LD50 values with animal studies </li></ul></ul><ul><ul><li>NOTE: TLVs/exposure limits are developed without considering skin exposure </li></ul></ul><ul><li>What does this mean for the OH professional? </li></ul><ul><ul><li>Systemic effects may occur due to dermal exposure over inhalation </li></ul></ul><ul><ul><li>Identifies need for PPE or other controls to limit skin exposure </li></ul></ul><ul><ul><li>Biological monitoring would be appropriate to monitor exposure </li></ul></ul>SKIN NOTATION
  8. 8. <ul><li>Odor or mild irritation detectable BELOW levels that are hazardous </li></ul><ul><li>Largely based on comparison of TLV to published odor thresholds </li></ul><ul><li>If using odor thresholds should preform odor threshold tests on each worker </li></ul><ul><li>Not good to use when: </li></ul><ul><ul><li>Odor threshold is over TLV </li></ul></ul><ul><ul><li>Odor threshold is very low (i.e. well below action limit) </li></ul></ul><ul><ul><li>Olfactory fatigue it common </li></ul></ul><ul><ul><li>Worker is unable to detect odor </li></ul></ul>WARNING PROPERTIES
  9. 9. <ul><li>Considerations using odor thresholds: </li></ul><ul><ul><li>Differences in odor thresholds across populations </li></ul></ul><ul><ul><li>Effects of aging (decrease smell ability with age) </li></ul></ul><ul><ul><li>Olfactory system can become fatigued (loose its sense of smell) </li></ul></ul><ul><ul><li>Number of conditions that can result in olfactory dysfunction </li></ul></ul><ul><ul><ul><li>rhinitis, sinusitis, polyps, </li></ul></ul></ul><ul><ul><ul><li>Inflammation and/or trauma to head </li></ul></ul></ul><ul><ul><ul><li>exposure to some chemicals (ex. metallics) </li></ul></ul></ul>WARNING PROPERTIES II
  10. 10. <ul><li>NOAEL </li></ul><ul><ul><li>No Observed Adverse Effect Level </li></ul></ul><ul><ul><li>Highest data point where there was no effect </li></ul></ul><ul><li>LOAEL </li></ul><ul><ul><li>Lowest Observed Adverse Effect Level </li></ul></ul><ul><ul><li>Lowest data point where there was an effect </li></ul></ul>NOAEL/LOEAL
  11. 11. <ul><li>Immediate vs. delayed effects </li></ul><ul><li>Reversible vs. irreversible </li></ul><ul><li>Local vs. systemic </li></ul><ul><ul><li>“ Local” - site  of action of the agent is at the point of contact </li></ul></ul><ul><ul><ul><li>Absorption does not necessarily occur </li></ul></ul></ul><ul><ul><li>“ Systemic”  - site of action other than the point of contact </li></ul></ul><ul><ul><ul><li>Absorption has taken place </li></ul></ul></ul>TOXIC EFFECTS CONSIDERATIONS
  13. 13. <ul><li>Network of cells responsible for communication </li></ul><ul><li>Contains high fat content  fat-soluble agents of concern and are more likely able to pass the blood-brain barrier </li></ul><ul><li>Broken into two categories: </li></ul><ul><ul><li>The central nervous system (CNS) </li></ul></ul><ul><ul><ul><li>includes the brain and spinal cord </li></ul></ul></ul><ul><ul><li>The peripheral nervous system </li></ul></ul><ul><ul><ul><li>Includes the nervous structures (motor and sensory nerves) that do not lie in the CNS </li></ul></ul></ul>NERVOUS SYSTEM
  14. 14. <ul><li>Set of glands responsible for hormone production and regulation of the body using feedback systems </li></ul><ul><li>Includes hypothalamus, adrenal, pituitary, pineal, and thyroid glands </li></ul><ul><li>Most common/important regulation roles include regulation of: </li></ul><ul><ul><li>Metabolism </li></ul></ul><ul><ul><li>Growth </li></ul></ul><ul><ul><li>Development </li></ul></ul><ul><ul><li>Reproductive cycles </li></ul></ul><ul><ul><li>Mood </li></ul></ul>ENDOCRINE SYSTEM
  15. 15. <ul><li>Responsible for distributing blood/lymph in the body </li></ul><ul><ul><li>Caries substances throughout the body and to and from cells </li></ul></ul><ul><ul><ul><li>nutrients, gases, hormones, enzymes, and waste </li></ul></ul></ul><ul><ul><li>Stabilizes body temperature and pH, and fights diseases </li></ul></ul><ul><li>Broken into two categories: </li></ul><ul><ul><li>The cardiovascular system </li></ul></ul><ul><ul><ul><li>I ncludes the heart, blood, and blood vessels </li></ul></ul></ul><ul><ul><li>The lymphatic system </li></ul></ul><ul><ul><ul><li>I ncludes the thymus, spleen, bone marrow, and lymphatic tissue </li></ul></ul></ul>CIRCULATORY SYSTEM
  16. 16. <ul><li>Primary function is to process/metabolize nutrients from the blood </li></ul><ul><ul><li>Also metabolizes other substances </li></ul></ul><ul><ul><li>Considered the body’s detoxifier; therefore, susceptible to toxins </li></ul></ul><ul><ul><li>Liver cells can regenerate after toxic damage, but prolonged/repeated exposure can lead to permanent liver damage </li></ul></ul><ul><li>Liver detoxification process can: </li></ul><ul><ul><li>Metabolize toxins into safe forms or metabolites </li></ul></ul><ul><ul><li>Metabolize toxins into more toxic metabolites </li></ul></ul><ul><ul><ul><li>Methanol  formaldehyde  formic acid </li></ul></ul></ul><ul><ul><ul><li>Metabolized by (1) alcohol and (2) aldehyde dehydrogenase enzymes </li></ul></ul></ul>LIVER
  17. 17. <ul><li>Includes kidneys, bladder, ureters, urethra, and sphincter muscles </li></ul><ul><li>Responsible for producing, filtering, storing, and excreting urine </li></ul><ul><ul><li>Primary function is to excrete unwanted waste products including toxins </li></ul></ul><ul><ul><li>Toxins typically have to be water soluble before they are excreted </li></ul></ul><ul><ul><ul><li>Non-water soluble toxins can be modified by liver to allow for excretion </li></ul></ul></ul><ul><li>Kidneys – maintain fluid and electrolyte balance by filtration and selective re-absorption into the blood </li></ul>URINARY SYSTEM
  19. 19. <ul><li>A hazard is the actual chemical/biological/physical agent that may cause harm if exposed. </li></ul><ul><ul><li>This is what you are being asked to provide in questions asking you to identify the hazards involved with a job, task, or industry.  </li></ul></ul><ul><ul><li>Examples: detergents, dust, bacteria, non-ionizing radiation, vibration </li></ul></ul><ul><li>A health outcome/effect is the outcome that may occur due to exposure to the hazard.  </li></ul><ul><ul><li>Examples: skin irritation, cancer, breathing difficulties, burns, hearing loss, amputations  </li></ul></ul><ul><li>A source of exposure (or exposure source) is the vehicle or process the exposure is originating from. </li></ul><ul><ul><li>Examples: cleaning, grinding, smelting, mixing, blood , feces/sewage </li></ul></ul><ul><li>A route of exposure is the manner in which people are exposed to the agent, or the way the hazard enters the body.  </li></ul><ul><ul><li>Examples: inhalation, skin contact/absorption, ingestion, injection </li></ul></ul>HAZARD TERMINOLOGY REVIEW
  20. 20. <ul><li>To clarify, when asked to provide the hazards, we want the actual agent that causes the harm (i.e. the chemical, biological, or physical agent) </li></ul><ul><ul><li>Often students can get confused and provide health effects or sources of exposures  loss of marks on assignments/quizzes </li></ul></ul><ul><ul><li>Sometimes this can be tricky, especially with physical hazards </li></ul></ul><ul><li>Correct answers will properly identify the hazard however, the best answer is to identify the hazard and include additional information such as the outcome, source/route of exposure to explain the hazard </li></ul><ul><li>The next slide outlines examples of this where: </li></ul><ul><ul><li>The first row will name the hazard </li></ul></ul><ul><ul><li>The second row will name the hazard and supplement it with explanatory information </li></ul></ul>HAZARD IDENTIFICATION
  21. 21. <ul><li>Vibration exposure </li></ul><ul><li>Whole body vibration from driving forklifts </li></ul><ul><li>Noise exposure </li></ul><ul><li>Hearing loss could occur due to exposure to noise from the operating equipment </li></ul><ul><li>Temperature extremes </li></ul><ul><li>Risk of heat stress occurring due to high/elevated temperatures. </li></ul><ul><li>Wood dust </li></ul><ul><li>Inhalation of wood dust from sawing operations </li></ul><ul><li>Welding fumes </li></ul><ul><li>Metal fume fever due to inhalation of welding fumes </li></ul><ul><li>Mold </li></ul><ul><li>Inhalation of fungal spores from water damaged ceiling tiles </li></ul><ul><li>Hepatitis C virus </li></ul><ul><li>Risk of contracting Hepatitis C from exposure to contaminated blood through a needle stick injury. </li></ul>HAZARD TERMINOLOGY EXAMPLES