1. TOXIC PLASTIC BOTTLESTOXIC PLASTIC BOTTLES? Information Literacy and Toxicology

2. CASE: BISPHENOL A (BPA) Bisphenol A, or BPA, is a synthetic chemical used since the 1940s used to line metal food cans and in the production of many plastic bottles and containers—including baby bottles. Studies began showing an association between BPA and serious medical conditions, from impaired neurological and sexual development to cancer. In 2008, the National Toxicology Program (NTP) analyzed studies about BPA. NTP stated it had “some concern” about the effects of BPA exposure on brain, behavior, and prostate glands in fetuses, infants, and children. BPA was then banned in Canada and the U.K., but the plastics industry challenged the science claiming BPA was safe. The NTP panel’s scientists felt that the data were still too uncertain to warrant such a drastic step, but suggested that industries should start looking for a replacement chemical.

3. Toxic substance- chemicals that cause direct damage upon exposure (aka. Toxin) Natural toxins- not necessarily safe! Arsenic, a NATURAL basic element, can leach into ground water and cause cancer and nervous system damage in humans. Synthetic toxins (aka. Man-made)- problem because many are persistent chemicals—they don’t readily break down over time

4. Regulating toxins is a challenge Some chemicals have large effects in small doses. Certain stages of human development are especially vulnerable to effects. Mixtures of different chemicals can have unexpected impacts.

5. THE EPA The U.S. Environmental Protection Agency- a regulatory agency of the federal government that establishes rules and regulations to support environmental law as it is passed “ Our mission is to protect human health and the environment.“ Established in 1970 under President Nixon

6. According to the EPA: More than 80,000 chemicals are used in the United States 1,000-2,000 new chemicals enter the market each year How do we determine which are safe?

7. Regulation of toxins begins with risk assessment. Goal: weigh the costs and benefits associated with any specific chemical In a perfect world, what would be the best ways to assess the safety of a chemical? We want unbiased, professional regulations that assess the safety of every new chemical before it enters our lives.

8. Regulation of toxins begins with risk assessment. We want unbiased, professional regulations that assess the safety of every new chemical before it enters our lives. Why don’t we have that in reality? What are the limitations? In reality, it is impossible to fully understand and assess all potential interactions among the many chemicals to which we are exposed on a daily basis. practicality, economic forces, and the basic need for the chemical

9. So what should we do? (Option 1) Leave a wide safety margin when setting the exposure limit—the maximum quantity humans can be exposed to Favored tactic in the European union and Canada “Better safe than sorry” Known as the precautionary principle

10. So what should we do? (Option 2) Regulators make educated guesses about safety based on the effects of other similar chemicals Toxic products are recalled, often after someone has been harmed Leaves the burden of proof on the public. “Innocent until proven guilty”

11. INFORMATION LITERACY What is information literacy and why is it important?  Published information about toxics (and other scientific topics) abounds in our modern world. It is up to an individual, using information literacy skills, to determine the reliability of that information.

12. Information literacy- the ability to distinguish between reliable and unreliable resources Goal: draw reasonable, evidence-based conclusion about an issue or topic When it comes to scientific issues, hyperbole and misinformation is abound

13. Primary sources include new and original information from research—usually rigorously reviewed by peers in the scientific community for design, data, and analysis. Peer review- process by which experts in the field (peers) assess the quality of a study’s design, data, analysis, and conclusions Ex. Articles in scholarly journals, interviews, other reports and books based on primary research

14. Secondary sources include interpretation of primary sources and lack of peer review. This is what you read in the popular press. Ex. scholarly reviews and editorials, nonprofit agency publications, books, magazines and newspaper articles, government agencies

15. Tertiary sources interpret information from secondary sources, often over-simplifying, while providing additional commentary and stimulating debate over an issue. Ex. Blogs, websites, news shows, Caution: may be accurate, but may introduce errors because they do not rely on original source for facts or perpetuate errors within a secondary source.

16. PART 3: GUIDING QUESTIONS What factors influence a chemical’s toxicity? Why is solubility of a toxic substance important to individuals and ecosystems? Key Terms: Persistence Solubility Bioaccumulation Biomagnification Epidemiologist Toxicologists In vitro study In vivo study

18. CASE: BPA In the wake of the NTP’s 2008 report, a team of scientists from the Center for Disease Control and Prevention (CDC) focused their own research: They studied 2000 urine samples from various Americans. More than 90% of samples tested positive for BPA with an average concentration 2.6 parts per billion (ppb). The top 5% of samples contained almost 16 ppb – Beyond the amount found to cause harm in rodents. Concentration of BPA decreased with age (children had more BPA in systems than adults) Results are in, but does that mean BPA is dangerous for humans?

19. EVALUATING SAFETY 1. How persistent is the substance? (how long it takes to break down) Low persistence - Breaks down quickly with sunlight High persistence - Long time to break down and potential environmental impact long after initial release

20. EVALUATING SAFETY 2. How soluble is the substance? (its ability to dissolve in a liquid) Water and other liquids: May be safer for humans—get rid of it in urine Still potential toxic at high doses or continual low dose High impact on aquatic organisms—easy uptake Fat-soluble: Can enter cells and is harder to eliminate by the body Some break down by liver Storage and accumulation in fatty tissue

21. EVALUATING SAFETY Bioaccumulation—buildup of fat-soluble substances in tissues of an organism over time.

22. EVALUATING SAFETY Biomagnification – Higher on the food chain and able to consume the entire lifetime of toxins in their prey

23. Ex. Tuna and swordfish are large predators high on the ocean food chain. They accumulate and magnify mercury, pcbs, and DDT. When we eat tuna and swordfish, we consume all the toxic substances (mercury) they have picked up from preying on smaller fish.

24. CASE: EVALUATING THE SAFETY OF BPA BPA has a low persistence. It is fat soluble, but liver and gut cells can readily convert it to water soluble forms and excrete. They should not bioaccumulate or biommagnify. So, why is it present in more than 90% of samples? BPA is so common that people are exposed to it continuously.

25. EVALUATING SAFETY: SCIENTISTS Epidemiologists—scientists that research the impact of chemicals on humans They can’t just give a group of people a toxic substance and see what happens, they have to work backwards. Find a group that has negative impacts and determine why Toxicology - Determining properties of toxins and their effects on cells and tissues Testing on animals—in vivo (“in body”) Testing cells in petri dishes—in vitro (“in glass”)

30. CASE: EVALUATING SAFETY When looking at individuals with BPA in urine, researchers found correlation between BPA concentration and cardiovascular diseases and diabetes. In vivo and in vitro studies both show negative effects of BPA—one on prostate size, the other on cell survival.

31. EVALUATING SAFETY: Factors affecting toxicity Toxicity of a substance depends on a number of factors: Individual- age, general health status, genetics Exposure – mode of contact (inhaled, ingested, or contacts the skin), frequency of exposure also matters Chemical Interactions

32. EVALUATING SAFETY: Factors affecting toxicity Chemical Interactions Additive effects – Other chemicals may increase the effect of the toxin.

33. Antagonistic effects – Other chemicals reduce or cancel the toxin’s effects. Synergistic effects – Chemicals increase the effects of the toxin, even beyond expectations.

34. EVALUATING SAFETY: Factors affecting toxicity Chemical Interactions Additive effects – Other chemicals may increase the effect of the toxin. Antagonistic effects – Other chemicals reduce or cancel the toxin’s effects. Synergistic effects – Chemicals increase the effects of the toxin, even beyond expectations.

35. COMMON LOGICAL FALLACIES MeaningExample Hasty generalization Drawing a broad conclusion on too little evidence “…Baby formula… all contained BPA” Containing BPA doesn’t mean its dangerous. Red herring Provide information that does not directly support the claim but might confuse the reader “Buildup of toxic chemicals…lead to health problems” Well, duh. Does BPA build up? What toxic chemicals? This has nothing to do with BPA. Ad hominem attack Attack the person/group representing opposite view instead of addressing evidence “self serving plastics industry” Well, that may be true, but why? What evidence do they have? Appeal to authority Not direct evidence, but makes a case that “experts” agree with “scientists suspect BPA might be linked to several medical problems…” Appeal to ignorance States that the issue is too complex. The reader is not capable of understanding it “we cannot possibly predict the specific effects that may arise” False dichotomy Either/or choice that is not valid. *issues in env sci are rarely black and white so this is rarely accurate Stop using BPA

36. Fold piece of notebook paper. Write your names on it. Obtain a “claim”. Read your claim. Work with your table partner to generate a supporting argument regarding our claim. Incorporate as many logical fallacies into your argument as you can. Be as convincing as you can. Refer to your notes for help. Trade arguments with the group across from you. Work with your partner to evaluate the argument by identifying as many logical fallacies as you can find.

37. THINKING CRITICALLY 1.Be skeptical. Require evidence before accepting a claim as reasonable. See science news article 2.Evaluate the evidence. Is the claim from actual scientific studies? How relevant are the studies? Did the researchers look at human populations? Vom Saal evaluated 115 published studies None of the 11 plastics industry-funded studies found adverse effects from BPA 94 of 104 government funded studies showed significant effects of BPA Many industry-funded studies that did not find low dose effects used rodents that were not sensitive to estrogen. If they weren’t affected by estrogen, then they wouldn’t be adversely affected by an estrogen mimic.

38. 3. Be open-minded. Identify your own biases or pre- conceived notions and follow the evidence where it takes you. 4. Watch out for biases. Is the author promoting a specific position? Are they financially tied to a specific conclusion? Are they trying to support a predetermined conclusion? See risk in perspective article. Often cited by plastics industry. Report only looked at 19 of 47 published studies. Funded by the American Plastics Council

39. TAKE AWAY MESSAGE… There are rarely easy answers and science is never as straightforward as we would like it to be. We are constantly uncovering new information and as our understanding grows, existing information often becomes obsolete. Science is incremental: Each study is a piece of the puzzle. “Sometimes, if there’s enough momentum from the public, regulatory change will follow. But more often than not, because of the way the system works, it really has to start with individual consumers deciding for themselves that they won’t purchase or use certain items.”

40. By 2011, both Canada and the European Union banned BPA; the United States followed in late 2012, with an official ban on BPA in baby bottles and “sippy” cups. Even before the U.S. ban, more and more companies had stopped using the chemical. In fact, many plastic bottles now tout their BPA-free status. What replaced it? A very similar chemical known as BPS (bisphenol S).

41. PART 1 What is a toxic substance? How are toxic substances regulated? How do we make decisions regarding the risks of exposure to these chemicals? Toxins Persistent chemicals EPA Risk assessment Precautionary principle

42. PART 2 What is information literacy and why is it important? Information literacy Primary sources Peer review Secondary sources Tertiary sources

43. PART 3 What factors influence a chemical’s toxicity? Why is solubility of a toxic substance important to individuals and ecosystems? Persistence Solubility Bioaccumulation Biomagnification Epidemiologist Toxicologists In vitro study In vivo study

44. PART 4 What are endocrine disruptors? Why is it often harder to determine a “safe dose” of them than it is to determine safe doses of other types of toxic substances? Endocrine disruptor Hormone Dose-response curve LD50

45. PART 5 How can we use critical thinking skills to logically evaluate the quality of information and its source? What common logical fallacies are used in presenting arguments? Critical thinking Logical Fallacies