1. Chapter 17 Environmental Hazards and Human Health

2. Core Case Study: Are Baby Bottles and Food Cans Safe To Use
Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (1)
Bisphenol A (________) mimics the hormone _________________ disrupting the human endocrine system
Excess estrogen effects on
males
Feminization
Smaller penis
Lower sperm counts
Presence of both male and female sex organs
BPA
estrogen

3. Core Case Study: Are Baby Bottles and Food Cans Safe To Use
Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (2)
BPA (bisphenol A) has been used in…
polycarbonates and other _______________ plastics
___________ bottles and sipping cups
Reusable water bottles
Sports drink and juice bottles
___________________ dishes
Food storage containers
Liners of most food and soft drink _________
hardened
baby
microwaveable
cans

4. Core Case Study: Are Baby Bottles and Food Cans Safe To Use
Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (3)
BPA can leach into foods and drinks…even when containers are not heated
_______ of Americans older than 6 have trace levels BPA in their urine above the threshold level set by the EPA (CDC, 2007)
Higher in children and adolescents
How do scientists determine the potential harm from exposure? How serious is the risk?
93%

5. 17-1 What Major Health Hazards Do We Face?
Concept We face health hazards from biological, chemical, physical, and cultural factors, and from the lifestyle choices they make.

6. Risks Are Usually Expressed as Probabilities
A risk is the ___________________ of suffering harm from a hazard
Probability vs. possibility
Mathematical statements
“The lifetime probability of developing lung cancer from smoking one pack of cigarettes per day is 1 in 250.”
Risk ______________________ – using statistical methods to estimate how much harm a hazard can cause to human health or the environment
Risk ______________________ – deciding whether or how to reduce a particular risk
probability
Assessment
Management

7. Science: Risk Assessment and Risk Management
Figure 17.2: Science.
Risk assessment and risk management are used to estimate the seriousness of various risks and how to reduce such risks. Question: What is an example of how you have applied this process in your daily living?
Fig. 17-2, p. 437

8. We Face Many Types of Hazards
Biological: _________________, called pathogens, that causes disease in other organisms
Chemical: pesticides, toxic metals…etc.
Natural: fires, earthquakes, floods…etc.
Cultural: unsafe _________________ conditions, poverty, criminal ________________
Lifestyle choices: smoking, poor food choices
Organisms
working
assault

9. 17-2 What Types of Biological Hazards Do We Face?
Concept The most serious biological hazards we fade are infectious diseases such as flu, AIDS, tuberculosis, diarrheal diseases, and malaria.

10. Some Diseases Can Spread from One Person to Another (1)
Infectious
_________________________ disease
Pathogen invades the body and multiplies
Transmissible disease
__________________ or ________________________ disease
Infectious disease transmitted between people
Ex: Flu, tuberculosis, measles
Nontransmissible disease
Not caused by living organisms
Usually develop slowly due and have multiple causes
Heart disease, most ______________, _________________
Contagious
communicable
cancers
diabetes

11. Infectious Diseases Are Still Major Health Threats
Since 1950, death from infectious diseases have ____________________ due to
Better health care
Better sanitation
Antibiotics
Vaccines
Still a major threat though, especially in __________
Large scale outbreak with a country: ______________
Global epidemic, like AIDS, is called a ______________
decreased
LDCs
epidemic
pandemic

12. Science: Pathways for Infectious Diseases in Humans
Figure 17.3: Science.
There are a number of pathways on which infectious disease organisms can enter the human body. Question: Can you think of other pathways not shown here?
Fig. 17-3, p. 439

13. Major Causes of Death from Infectious Diseases in the World, 2007
Figure 17.4: Global outlook: The World Health Organization estimates that each year, the world’s seven deadliest infectious diseases kill 11.3 million people—most of them poor people in less-developed countries (Concept 17-2). This averages about 31,000 mostly preventable deaths every day—roughly the same as wiping out everyone in the U.S. states of Massachusetts and Alabama or all the people in Delhi, India, each year. Question: How many people, on average, die prematurely from these diseases every hour? (Data from the World Health Organization, 2007)
Fig. 17-4, p. 439

14. Science Focus: Genetic Resistance to Antibiotics Is Increasing (1)
One reason why infectious disease is still a serious threat is that many disease carrying bacteria have developed __________________________ to widely used antibiotics and pesticides
extremely high reproductive _______________
Overuse of pesticides
Use of antibiotics when not necessary…not finishing all of your antibiotics!
Widespread use of antibiotics in _______________ and _____________ animals
genetic resistance
rates
livestock
dairy

15. Case Study: The Growing Global Threat from Tuberculosis
Since 1990, one of the most underreported stories has been the __________________ of tuberculosis.
Extremely contagious bacterial infection of the __________
____________ will become sick
with TB
1.8 million deaths each year,
primarily in LDCs
rapid spread
lungs
1 in 10

16. Case Study: The Growing Global Threat from Tuberculosis
Why is tuberculosis on the rise?
Not enough _________________ and control programs
in LDCS patient samples must be sent to labs for analysis, which can take ___________
Genetic ____________________ to a majority of effective antibiotics
Drugs must be taken for ____________...many people stop ahead of time
Travel and _______________________ contact has increased
AIDS individuals are very susceptible to TB
screening
months
resistance
6-9 months
person- to person

17. Viral Diseases and Parasites Kill Large Numbers of People (1)
Viruses evolve quickly and ____________ be treated with antibiotics
#1 Killer Flu
#2 Killer HIV
#3 Killer Hepatitis B virus (HBV)
Emergent diseases: _____________ discovered or absent from the human population for at least 20 years
West Nile virus…mosquito to human
Chance of being infected and killed is ___________
cannot
newly
low

18. Viral Diseases and Parasites Kill Large Numbers of People (2)
Ecological medicine studies viruses that move from ______________________
West Nile virus – bird to mosquito to humans
Lyme Disease – deer to ticks to humans
HIV – chimps to humans
Hepatitis B – apes to humans
Avian Flu – wild birds to chickens to humans
animal to human

19. Case Study: Malaria — The Spread of a Deadly Parasite (1)
Caused by protozoan parasites in the genus _________________...transferred through Anopheles mosquito bites
Tropical and subtropical regions
Destroys ____________________, causing symptoms such as…
Fever, sweating, severe abdominal pain, vomiting, headaches
Kills an average of 2700 people per day….90% younger than ________
Plasmodium
red blood cells 5

20. Case Study: Malaria — The Spread of a Deadly Parasite (2)
Malaria on the rise since 1970
Drug ____________________ Plasmodium
Insecticide resistant ____________________
Clearing of tropical forests has led to the spread among workers
AIDS patients particularly vulnerable
Prevention of spread and current research
Developing new drugs
Developing _____ mosquitoes that resist the parasite and ______________the malaria carrying mosquitoes
Mosquito __________ and DDT
resistant
mosquitoes GE
outbreed
nets

21. A Boy in Brazil’s Amazon Sleeps Under an Insecticide-Treated Mosquito Net
Figure 17.7: This boy, who lives in Brazil’s Amazon Basin, is sleeping under an insecticide-treated mosquito net to reduce his risk of being bitten by malaria-carrying mosquitoes. Such nets cost about $5 each and can be donated through groups such as
Fig. 17-7, p. 445

22. Solutions Infectious Diseases
Increase research on tropical diseases and vaccines
Reduce poverty
Decrease malnutrition
Improve drinking water quality
Reduce unnecessary use of antibiotics
Educate people to take all of an antibiotic prescription
Reduce antibiotic use to promote livestock growth
Figure 17.8: There are a number of ways to prevent or reduce the incidence of infectious diseases, especially in less-developed countries. Question: Which three of these approaches do you think are the most important?
Require careful hand washing
by all medical personnel
Immunize children against major viral diseases
Provide oral rehydration for diarrhea victims
Conduct global campaign to reduce HIV/AIDS
Fig. 17-8, p. 445

23. 17-3 What Types of Chemical Hazards Do We Face?
Concept There is growing concern about chemicals in the environment that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine system.

24. Some Chemicals Can Cause Cancers, Mutations, and Birth Defects
Toxic chemicals
Carcinogens
Chemicals, types of radiation, or certain viruses the cause or promote __________________
Mutagens
Chemicals or radiation that cause DNA _________________ or increase their frequency
Teratogens
Chemicals that cause harm or birth defects to a ______________ or embryo
cancer
mutations
fetus

25. Case Study: PCBs Are Everywhere—A Legacy from the Past
Class of ____________ containing compounds
Very ______________
_______________________
Widely used in lubricants, hydraulic fluids, paints, fabrics, preservatives, adhesives, pesticides
U.S. Congress banned their production in 1977 after research showed they caused __________________ and other cancers
Break down slowly in the environment
Travel long distances in the air
Fat soluble…Biomagnification
1996 studied linked fetal exposure in the womb to _________________ disabilities
chlorine
stable
nonflammable
liver cancer
learning

26. Potential Pathways on Which Toxic Chemicals Move Through the Environment
Figure 17.9: PCBs and other persistent toxic chemicals can move through the living and nonliving environment on a number of pathways.
Fig. 17-9, p. 447

27. Some Chemicals May Affect Our Immune and Nervous Systems
Some natural and synthetic chemicals in the environment can weaken and harm…
Immune system – protects our bodies from __________
Arsenic, ,methylmercury, dioxins
Nervous system – brain, spinal cord, peripheral nerves
_____________________: PCBs, arsenic, lead, some pesticides
Endocrine system – network of glands that release ___________________
Gender benders…atrazine, BPA, phthalates
disease
neurotoxins
hormones

28. Science Focus: Mercury’s Toxic Effects (1)
element
Mercury is an ____________________
teratogen and potent neurotoxin
Released into the air through volcanoes, burning ___________, and waste __________________
When it rains, Hg enters our water and soil
How are humans exposed?
_______________________: vaporized Hg or particulates
Eating ______________ with high levels of methylmercury
Eating ____________________________
coal
incinerators
Inhalation
fish
high fructose corn syrup

29. Science Focus: Mercury’s Toxic Effects (2)
Effects of Hg on humans
Damage nervous system, kidneys, lungs
Harm fetuses and cause birth defects
Who is most at risk?
_________________ and young children
_____________ women of child-bearing age in the U.S. has enough mercury in her blood to harm her developing fetus
75% of exposure comes from eating fish
fetuses
1 in 12

30. 17-4 How Can We Evaluate and Deal with Chemical Hazards?
Concept 17-4A Scientists use live laboratory animals, case reports of poisonings, and epidemiological studies to estimate the toxicity of chemicals, but these methods have limitations.
Concept 17-4B Many health scientists call for much greater emphasis on pollution prevention to reduce our exposure to potentially harmful chemicals.

31. Many Factors Determine the Harmful Health Effects of a Chemical (1)
The study of the harmful effects of chemicals on humans and other organisms is called _______________________
Toxicity depends on
____________ – amount you’ve been exposed to
Age
Genetic makeup
Multiple chemical sensitivity (MCS)
Solubility
__________________ – resistance to breakdown
Biomagnification
toxicology
dose
persistence

32. Many Factors Determine the Harmful Health Effects of a Chemical (2)
The damage to health resulting form exposure to a chemical is called the _______________
Acute effect: immediate or rapid
Chronic effect: permanent or long-lasting
response

33. Case Study: Protecting Children from Toxic Chemicals
Infants and children more susceptible
Eat, drink water, and breathe more per unit of ________________ than adults
Put their fingers in their mouths
Less well-developed ___________________ and body detoxification processes
Fetal exposure may increase risk of autism, asthma, learning disorders
body weight
immune systems

34. Scientists Use Live Lab Animals and Nonanimal Tests to Estimate Toxicity (1)
The most widely used method for determining toxicity is to expose a population of live laboratory animals to measured ___________ of a substance.
Mice and rats
Systems are similar to humans
Small, and reproduce rapidly
Can take _________ years to complete, involve thousands of test animals, cost as much as _________________ per substance tests
doses
2-5
$2 million

35. Scientists Use Live Lab Animals and Nonanimal Tests to Estimate Toxicity (1)
Scientists estimate the toxicity of a chemical by determining the effect of various doses and plotting the results in a __________________________
A chemical’s median lethal dose (_______) is the dose that kills ______ of the animals in a test population within an 18-day period
dose response curve
LD50
50%

36. Percentage of population killed by a given dose
100 75 50
Percentage of population killed by a given dose 25
Figure 17.13: Science.
This hypothetical dose-response curve illustrates how scientists can estimate the LD50, the dosage of a specific chemical that kills 50% of the animals in a test group. Toxicologists use this method to compare the toxicities of different chemicals.
LD50 2 4 6 8 10 12 14 16
Dose (hypothetical units)
Fig , p. 453

37. 17-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them?
Concept We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices.

38. The Greatest Health Risks Come from Poverty, Gender, and Lifestyle Choices
Greatest health risks world-wide are caused by…
___________________
Malnutrition, unsafe drinking water
____________________ choices
Smoking, saturated fats, too much sun exposure
poverty
gender
lifestyle

39. Global Outlook: Number of Deaths per Year in the World from Various Causes
Figure 17.16: Global outlook: Scientists have estimated the number of deaths per year in the world from various causes. Numbers in parentheses represent death tolls in terms of the number of fully loaded 200-passenger jet airplanes crashing every day of the year with no survivors. Because of the lack of media coverage of the largest annual causes of death and its sensational coverage of other causes of death, most people are misinformed and guided by irrational fears about the comparative levels of risk. Question: Which three of these items are most likely to shorten your life span? (Data from World Health Organization, 2007)
Fig , p. 458

40. Most People Do a Poor Job of Evaluating Risks
Fear...people often fear ______________ risks more
Some fear flying more than the flu
Degree of ________________
May fear flying more than driving
Whether a risk is ________________ or _________
Flying versus smoking
Optimism _______…risks don’t apply to you
Texting while driving
Instant gratification without thinking of ________ harm
Smoking, tanning
unusual
control
catastrophic
chronic
bias
future

41. Several Principles Can Help Us to Evaluate and Reduce Risk
Compare risks…how risky is the risk compared to others?
Determine how much risk you are willing to accept
Determine the actual risk involved…may be exaggerated by the media
Concentrate on evaluating and carefully making important lifestyle choices…you have ____________ over these
control

42. Three Big Ideas
We face significant hazards from infectious ______________, malaria, and tuberculosis, and from exposure to ________________ that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems.
Because of the difficulty in evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution ____________.
Becoming ______________________, thinking critically about risks, and making careful choices can reduce the major risks we face.
diseases
chemicals
prevention
informed