Presentation Transcript

1. Annual Deaths and Their Causes Red numbers indicate the number of 747 Jumbo Jets crashing every day of the year with no survivors!
2. What are Risks? Risk is the possibility of suffering harm from a hazard that can cause injury, disease, economic loss or environmental damage. What are some different hazards?
3. Toxic Chemicals Fatal to over 50% of test subjects at given concentrations Can be Industrial or Agricultural Ex: Dioxin, mercury cyanide, benzene chloroform Kill cell or impair their function
4. Hazardous Chemicals Flammable or explosive Irritating to skin or lungs Interfere with oxygen uptake Induction of allergic reactions Interference with endocrine (hormone) system
5. Mutagens Chemicals or radiation that cause mutations Can cause cancer or congenital (present at birth) defects.
6. Carcinogens Chemicals, radiation or viruses that cause malignant (cancerous) tumors. Cancer: Cells cannot regulate their growth, divide uncontrollably, and metastasize (break off from tumors and travel to other parts of the body).
7. Carcinogens 2nd highest cause of death in the U.S. Rates of cancer survival are increasing as treatment gets better
8. Teratogens Chemicals, radiation, viruses that cause birth defects during pregnancy ex. Alcohol Fetal Alcohol Syndrome (FAS)- mental defects, developmental delays, behavioral problems
9. Neurotoxins Metabolic poisons attack nerves Anesthetics (Ether, Chloroform) Chlorinated hydrocarbons (DDT) Heavy metals (Lead, Mercury) Organophosphates (Malathion) Carbamates (Sevrin) Toxic and fast acting
10. Ionizing Radiation Radiation with enough energy that it can remove tightly bound electrons from the orbit of an atom, causing the atom to become charged or ionized. Health Effects: Beyond certain thresholds, radiation can impair the functioning of tissues and/or organs and can produce acute effects such as skin redness, hair loss, radiation burns.
11. Heavy-Metal Poisoning“Minimata Disease” or “Mad as a Hatter”Mercury is Fat Soluble
12. Asphyxiants Interfere with oxygen uptake Passive: carbon dioxide, methane Active: carbon monoxide (replaces oxygen in hemoglobin), hydrogen cyanide, hydrogen sulfide
13. Hormone Mimics and Disrupters Figure 10-4 These chemicals prevent natural hormones from attaching to their receptors. (dioxins, PCB’s, plastics, pesticides, lead, mercury, BPA)
14. Respiratory Fibrotic Agents Irritants that damage lung tissue and cause formation of scar tissue with limits lung capacity ex. Coal dust causing black lung (coal) asbestosis, brown lung (cotton)
15. Cultural Hazards Smoking Nation’s leading cause of preventable death # of deaths equal to 3 jumbo jets crashing every day (1,150/day) only 1 in ten can quit 30-40% of cancers caused by smoking.
16. Physical Hazards Ionizing Radiation –Electromagnetic radiation with enough energy to damage body tissues. Radiation knocks loose electrons from a cellular chemical altering cell function Genetic – DNA Somatic - Tissue
17. Persistence and Chemical Interactions Persistence - how long a chemical remains in the environment
18. Chemical Interactions Antagonistic reactions - interfere with the effects of or stimulate the breakdown of other chemicals – antioxidants Additive effects - effects are added together Synergistic effects - when combination is worse than added effects
19. Magnification (additive) Bioaccumulation: The build up of a substance in an individual organisms tissue Biomagnification : Increase in concentration of a toxin as it passes up the food chain.
20. Biological Hazards transmissible by living organisms. Pathogens spread by air, water, food, body fluids such as bacteria, virus, protozoa, parasites. Non-transmissible does not spread from person to person such as most cancers, heart disease, diabetes. Etc.
21. Who Performs Risk Analysis? The EPA (Environmental Protection Agency) Began in 1970’s to estimate cancer risks as a result of exposure
22. What are the 4 steps? 1. Risk assessment 2. Dose-response assessment 3. Exposure assessment 4. Risk characterization
23. 1. Risk Assessment Determining types of hazards Probability that each will occur How many people will be exposed How many will suffer serious harm
24. 1. Risk Assessment Two methods: Epidemiology - tracks how sickness spreads through community - can establish links Animal testing - gives more immediate results (remember cats and Minimata?)
25. 2.Dose-Response Assessment Dose and Response Relationship: Dose- amount of substance someone has taken in Acute exposure - single dose Chronic exposure - long-term exposure
26. 2.Dose-Response Assessment Response - type and amount of damage Acute effect - immediate or rapid reaction to exposure Chronic effect - permanent or long-lasting effect
27. Dose-Response CurvesLinear relationshipfor some carcinogensThresholdThere is a minimal dosage necessary for a response Linear – there is an immediate response (example: smoke inhalation) Threshold – there is no immediate response. Levels must build up in the system (example: mercury poisoning)
28. Range of Tolerance All species have: Minimum and maximum levels of tolerance to any environmental factor in order to live. They will not live outside that level. They will exist in fewer numbers at the edges of the range.
29. Solubility Solubility is the quantity of a particular substance that can dissolve in a particular solvent One of the most important characteristics determining how a toxin will move through a body or environment
30. Solubility Water-soluble compounds move rapidly in environments and throughout the body. Ex: Vitamins: B-complex and C Fat-soluble compounds have trouble getting into body, but once in, readily penetrate cells and are accumulated over time. Ex: Vitamins A, Lead, DDT, Mercury
31. Measuring Toxicity Lethal Dose - LD50 Amount of a chemical that is required in one dose to kill 50% of test population in 14 days
32. 3. Exposure Assessment Estimation of intensity, duration, and frequency of human exposure to hazard Exposure hazard: more people exposed the greater the risk closer the people to the source the greater the risk.
33. 4. Risk Characterization Pull together all information in first three steps to determine magnitude of the risk and its accompanying uncertainties