Tues. Dec. 7 Powerpoint presentations due this week Review sheet for Exam 3 Review in lecture Thursday – bring review sheet! EXAM 3 during finals –12:15 Lecture: Sun. Dec. 12, 3:15 pm –1:40 Lecture: Mon. Dec. 13, 1 pm

Final Project Presentations Introduction slide Slide showing the outline of the talk, 2-3 slides from each person Group conclusion about all of the substances Use footnotes (or other format) to cite references in the slides. Slide showing references Follow the “Tips for Effective Powerpoint Presentations” (in course packet) – use appropriate font size, colors, not too many words on each slide, don’t read the slides Bring a printed copy of your presentation slides

Environmental Health & Toxicology The main questions: How should you decide when to avoid a potentially harmful substance? How should society decide when to ban a potentially harmful substance?

Mercury Naturally occurring in soil, rocks Gets into air from burning coal, trash In water, becomes methylmercury=toxic Builds up in food chain  high in fish Large amounts  neurological problems; cardiovascular disease; stroke Children of mothers who eat a lot of high-mercury fish show reduced IQ, delayed development Studies also show that children who eat some fish show higher IQ and better development – omega fatty acids in fish Avoid fish or not? – Experts say: Eat some fish; avoid the high mercury fish

III. Decision-making Risk assessment & Risk management Risk - the probability of harm times the probability of exposure Risk Assessment = weighing costs vs. benefits; Risk Management= minimizing risk Ex. Mercury in fish Mercury is a neurotoxin; but fish is very healthy food Risk perception: A number of factors influence how we perceive relative risks associated with different situations. Accepting risks - we go to great lengths to avoid some dangers, while gladly accepting others – why? There are benefits to these risks!

Risk perception We are not always rational Social, political, and economic interests affect how you view risk e.g. make $ from it, downplay the risk People don’t understand probabilities –Probability of dying from car accident 1/100 We overestimate our control over our own lives News media give biased perspective – over-report some types of risks (murder), under-report others (heart disease) Irrational fear of some technologies – e.g., nuclear power; while accepting others e.g. burning coal (coal  10,000 deaths per yr in US!)

If the probability of injury from riding in a car is 1/5000, 1.Out of every 5,000 people, 1 will likely be injured 2.If you ride in a car 5,000 times, you will definitely get injured 3.If you ride in a car once without injury, the next time your ride in a car, the chances of an injury occurring are 1 in 4999

You have to choose between 5 activities. Assuming you want to live, which is the safest choice? 1.Has a 1/10,000 chance of injury 2.Has a 1/10,000 chance of death 3.Has a 1/100 chance of injury 4.Has a 1/100 chance of death 5.Has a 1/10 chance of injury

Accepting Risk 1/100 chance of death means that 1 person in 100 will die People will accept risky events that have a high probability of occurrence, if severity of injury is low People avoid risks that have more severe impacts E.g., 1/10,000 chance of death sounds worse than 1/100 chance of injury

Risk Assessment (RA) Government conducts RA – Steps: How bad is it? (Costs) 1.Identify hazard (what is it) 2.Find out harmful amount (dose-response) 3.Determine who is exposed, how much, frequency, duration of exposure, effects How important is it? (Benefits) 1.What does it do for us 2.Who benefits Weigh the Costs and Benefits (measure in $?!) Consider social justice, environment, economics Manage the risk=minimize it!

Regulatory Decisions

Movie: NO GRAPES Write down: 1.What is the goal of the movie – is it unbiased? 2.What evidence (facts) do they present 3.What is known for certain about these substances 4.What are the risks and benefits – and who gets the risk, who gets the benefits

After seeing the movie, I would 1.Not eat any grapes unless they are organically grown 2.Only eat organic grapes AND lobby EPA to stop the use of these pesticides 3.Keep eating grapes, but get more information about the pesticides 4.Not change my behavior at all

Movie “No Grapes” Goal of the film? Raise awareness? Strength of the evidence? Weak! Not very scientific, did present some facts but no sources Didn’t prove that the pesticides caused any of the illnesses Risk Assessment: Apply the Principles of Toxicology, then weigh costs and benefits

II. Principles of Toxicology A.There are different types of env. risks (chemical, biological, physical) B. Different substances had different effects (asphyxiant, allergen, neurotoxin,mutagen, carcinogen, teratogen) C. Toxicity is affected by many factors (stability, movement, biomagnification, amount/dose, duration of exposure, type of organism, etc.) D. Identifying effects is difficult E. Risk management: Weigh costs and benefits, minimize risks

Risk Assessment - Captan Type of substance? Chemical Type of effects? Cancer, birth defects, acute poisoning, death –Low acute toxicity if eaten or breathed –Can irritate skin; Permanent damage to eyes –Kills fish; causes stunted growth –Evidence of teratogenecity in some studies Movement in the environment? Breaks down quickly; Does not bioaccumulate or biomagnify npic.orst.edu/factsheets/captangen.pdf

Risk Assessment – Captan on grapes Amount – how much is too much Exposure – how much do we get exposed to from grapes? 34 different pesticides used Can’t be washed off #12 out of top 12 “dirtiest” fruits/veggies

PAD=population =adjusted dose=amt a child or preg. Woman can tolerate w/o problems

ug is max dose for a small child, there is an average of 3.1 ug per serving of grapes 2.How many servings of grapes would the child need to eat to get cancer? 3.About Captan does not bioaccumulate – need to eat this every day 5.What dose does a field worker get everyday? Risk Assessment – Captan on grapes

Who is harmed? Farm workers, farm neighbors, consumers Benefits? Fungicide – kills fungus that kills the crops  cheaper grapes, sell more, make more money Who benefits? Company owners, consumers Are benefits greater than the costs? How to compare? Put $ value on everything

Risk management Different people/species, different sensitivities Effects of chronic as well as acute exposures Benefits as well as costs (harm) of the toxin! Does the toxin create more benefits than the damages? Combined effects of many different toxins together – rarely studied Govt minimizes risk by setting max. limits (standards) for environmental toxins. Consider:

news.org/wallet guide.php If you can’t always buy organic…buy low- pesticide foods =personal risk management