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Measuring Toxicity, Risk Assessment, and Public Policy

Measuring Toxicity, Risk Assessment, and Public Policy. Chapter 9 Notes APES 2008. MEASURING TOXCITY. Toxicity notes LD 50 (lethal dose, 50%) 50% of the test subjects are sensitive Do all species respond the same way? Is this really an accurate way to document toxins?.

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Measuring Toxicity, Risk Assessment, and Public Policy

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  1. Measuring Toxicity, Risk Assessment, and Public Policy Chapter 9 Notes APES 2008

  2. MEASURING TOXCITY • Toxicity notes LD 50 (lethal dose, 50%) 50% of the test subjects are sensitive Do all species respond the same way? Is this really an accurate way to document toxins?

  3. MEASURING TOXCITY • Oral LD50 of grain alcohol: 10.6 g/kg in young rats, 7.06 g/kg in aged rats. [4] • Oral LD50 of nicotine: 50 mg/kg in rats. [5] • Oral LD50 of Sodium chloride: 3000 mg/kg in rats [6] • LD50 of Tetrahydrocannabinol (active ingredient found in Cannabis): 1270 mg/kg in rats. • LD50 of batrachotoxin: estimated at 1 to 2 µg/kg in humans. • LD50 of Polonium 210: estimated at 10 (inhaled) to 50 (ingested) nanograms in humans makes this one of the most toxic substances known. One gram in theory could poison 100 million people of which 50 million would die.

  4. MEASURING TOXCITY • Moderate toxins 1g/kg body weight is lethal • Very toxic 1cg/kg body weight is lethal • Supertoxic 1mg/kg body weight is lethal

  5. Acute Effects vs. Chronic Effects Acute: exposure leads to immediate effects, that, if treated, go away EPA website Chronic: exposure causes problems for the rest of the subject’s life For example if a person drinks too much alcohol on a regular basis then their health may suffer as a result. The alcohol does not have a long biological halflife but it is supplied on a regular basis to the body of the person.

  6. Coffee the killer • Overall, caffeine is found in the beans, leaves, and fruit of over 60 plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding upon them.

  7. RISK ASSESSMENT RISK The probability of harm times the probability of exposure.

  8. Which is riskier? vs.

  9. Which is riskier?

  10. How about here?

  11. How about here?

  12. Who is to decide what risk means to you? Watch out for these traps:

  13. Risk Assessment Traps People with an agenda tend to downplay certain risks and bring others to the forefront to further their cause/agenda

  14. Risk Assessment Traps Make sure you understand what the probabilities REALLY mean. Case in point: DOWNS

  15. Risk Assessment Traps Personal experience can be your own worst enemy. Just because something hasn’t kicked your butt yet doesn’t mean it WON’T or CANNOT. EX: Last night.

  16. Risk Assessment Traps We judge ourselves to be better than we are at most things and that can get you into trouble. I am luck, I am wise, that won’t happen to me!

  17. Risk Assessment Traps We tend to fear new technology and grab onto familiar stuff that is actually possibly worse for us.

  18. WHAT MAKES RISK ACCEPTABLE? • A HOST OF RISKY BEHAVIORS IS LESS COMMON IN TODAY’S HIGH SCHOOL STUDENTS THAN IN THOSE 15 YEARS EARLIER, ACCORDING TO A NEW CDC REPORT. • THE CDC PUBLISHED ITS 2005 YOUTH RISK BEHAVIOR SURVEILLANCE STUDY IN A SPECIAL ISSUE OF THE CDC’S MORBIDITY AND MORTALITY WEEKLY REPORT. • THE SURVEY HAS BEEN GIVEN EVERY TWO YEARS SINCE 1991. IN 2005, IT INCLUDED NEARLY 14,000 STUDENTS NATIONWIDE IN GRADES 9-12. • THE SURVEY SHOWS SEVERAL MAJOR CHANGES SINCE 1991, INCLUDING WEARING SEATBELTS, RIDING WITH DRIVERS WHO HAD BEEN DRINKING ALCOHOL, EVER HAVING SEXUAL INTERCOURSE, CARRYING WEAPONS, AND USING CONDOMS.

  19. RISKY BUSINESS People will take risks if the danger is low. If the danger is high, folks are less likely to take risks.

  20. Defining RISK is a personal thing • Enjoyment • Profitability • Known vs. unknown • Amount of Control we perceive • How dangerous the results are • Emotions are more important than stats See chart page 201 of your booky wooky

  21. How do you establish public policy? We assess the risk to the best of our ability And then we manage the risk as best we can.

  22. Standards for Environmental Toxins • Combined effects • Different tolerances/sensitivities • Effects of chronic/acute dosages • Reasonability of the regulations • Cumulative effects of the soup of toxins we are exposed to on a daily basis

  23. COMMON RISKS • SEE TEXT PAGE 202

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