© cengage learning 2015 living in the environment, 18e g. tyler miller scott e. spoolman © cengage...
DESCRIPTION
© Cengage Learning 2015 We face health hazards from biological, chemical, physical, and cultural factors, and from the lifestyle choices we make 17-1 What Major Health Hazards Do We Face?TRANSCRIPT
© Cengage Learning 2015
LIVING IN THE ENVIRONMENT, 18eG. TYLER MILLER • SCOTT E. SPOOLMAN
© Cengage Learning 2015
17Environmental Hazards and Human Health
© Cengage Learning 2015
• AGENDA 10/21-Notes:
Ch 14 Environmental Health and Toxicology
-Duckweed data
© Cengage Learning 2015
• We face health hazards from biological, chemical, physical, and cultural factors, and from the lifestyle choices we make
17-1 What Major Health Hazards Do We Face?
© Cengage Learning 2015
• Risk – Probability of suffering harm from a hazard– Expressed as ratio or percentage
• Risk assessment– Using statistical methods to estimate harm
• Risk management– Deciding whether and how to reduce a
particular risk
Risks Are Usually Expressed as Probabilities
Fig. 17-2, p. 443
Risk Assessment
Risk Management
What is the hazard? How does it compare with other risks?
Risk reduction- How much should it be reduced?
Probability of risk-How likely is the event?
Risk reduction strategy- How will the risk be reduced?
Consequences of risk- What is the likely damage?
Financial commitment- How much money should be spent?
Comparative risk analysis-Hazard identification-
© Cengage Learning 2015
• Biological– Pathogen – an organism that causes disease
in other organisms
• Chemical– Harmful chemicals
• Natural– Fire, earthquakes, volcanoes, etc.
We Face Many Types of Hazards
© Cengage Learning 2015
• Cultural– Unsafe working conditions, poverty, etc.
• Lifestyle choices– Smoking, drinking too much alcohol, etc.
We Face Many Types of Hazards (cont’d.)
© Cengage Learning 2015
• The most serious biological hazards we face are infectious diseases such as flu, AIDS, tuberculosis, diarrheal diseases, and malaria
17-2 What Types of Biological Hazards Do We Face?
© Cengage Learning 2015
• Infectious disease– Pathogen invades the body and multiplies– Viruses, bacteria, parasites
• Transmissible disease – Contagious or communicable disease– Infectious disease transmitted between
people
Some Diseases Can Spread from One Person to Another
© Cengage Learning 2015
• Nontransmissible disease– Not caused by living organisms– Heart disease, most cancers, diabetes
• Epidemic– Large-scale outbreak of an infectious disease– Pandemic – global
Some Diseases Can Spread from One Person to Another (cont’d.)
Humans
Fetus and babies
Other humans
Water AirInsectsWild animalsLivestockPets Food
Stepped ArtFig. 17-3, p. 444
© Cengage Learning 2015
Disease (type of agent) Deaths per year
Pneumonia and flu (bacteria and viruses)
3.2 million
HIV/AIDS (virus) 2.1 million
Diarrheal diseases (bacteria and viruses) 1.9 million
Tuberculosis (bacteria) 1.7 million
Malaria (protozoa) 1 million
Hepatitis B (virus) 1 million
Measles (virus) 800,000 Stepped Art
Fig. 17-4, p. 445© Cengage Learning 2015
© Cengage Learning 2015
• Good news– Percentage of worldwide deaths resulting
from infectious diseases• Dropped from 35% to 15% from 1970 to 2008
– Vaccinations on the rise– Oral rehydration therapy
• Bad news– More money needed for medical research in
developing countries
We Can Reduce the Incidence of Infectious Diseases
Fig. 17.9, p. 453
Solutions
Infectious Diseases
Increase research on tropical diseases and vaccines
Reduce poverty and malnutrition
Improve drinking water quality
Reduce unnecessary use of antibiotics
Sharply reduce use of antibiotics on livestock
Immunize children against major viral diseases
Provide oral rehydration for diarrhea victims
Conduct global campaign to reduce HIV/AIDS
© Cengage Learning 2015
• There is growing concern about chemicals in the environment that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems
17-3 What Types of Chemical Hazards Do We Face?
© Cengage Learning 2015
• Toxic chemicals– Carcinogens
• Chemicals, types of radiation, or certain viruses the cause or promote cancer
– Mutagens• Chemicals or radiation that cause mutations or
increase their frequency
– Teratogens• Chemicals that cause harm or birth defects to a
fetus or embryo
Some Chemicals Can Cause Cancers, Mutations, and Birth Defects
© Cengage Learning 2015
• Class of chlorine-containing compounds– Very stable– Nonflammable– Break down slowly in the environment– Travel long distances in the air– Fat soluble– Ends up in food chains and webs
• Banned, but found everywhere
Case Study: PCBs Are Everywhere – A Legacy from the Past
© Cengage Learning 2015
• Some natural and synthetic chemicals in the environment can weaken and harm:– Immune system
• Some chemicals weaken the immune system
– Nervous system• Neurotoxins – PCBs, arsenic, lead, some
pesticides
– Example – Methylmercury• What are the effects of mercury poisoning?
Some Chemicals May Affect Our Immune and Nervous Systems
© Cengage Learning 2015
• All mercury compounds are toxic• One third in the atmosphere comes from
natural sources– Human activities provide the rest
• Two main human exposures– Fish contaminated with mercury– Inhalation of vaporized mercury
• Greatest risk is brain damage
Core Case Study: Mercury’s Toxic Effects
© Cengage Learning 2015Fig. 17-1, p. 442
Fig. 17.12, p. 455
Solutions
Mercury Pollution
Prevention ControlPhase out waste incineration
Sharply reduce mercury emissions from coal-burning plants and incinerators
Remove mercury from coal before it is burned Label all products
containing mercury
Switch from coal to natural gas and renewable energy resources
Collect and recycle batteries and other products containing mercury
© Cengage Learning 2015
• Endocrine system– Glands that release hormones that regulate
bodily systems and control sexual reproduction, growth, development, learning, behavior
• Hormonally active agents have similar shapes and bind to hormone receptors– Hormone mimics– Hormone blockers
Some Chemicals Affect the Human Endocrine System
© Cengage Learning 2015Fig. 17.13, p. 456
Hormone Estrogen-like chemical Antiandrogen chemical
Receptor
Cell
Normal Hormone Process
Hormone Mimic Hormone Blocker
© Cengage Learning 2015
Bisphenol (BPA)
-found in epoxy lining of canned foods-plastics bottles
© Cengage Learning 2015
• Reproductive problems• Decline in viable eggs• Males low levels
testosterone• Females increased
estrogen levels• Abnormal gonads• Multiple follicles,
premature testes
Alligators of Lake Apopka Florida
© Cengage Learning 2015Fig. 17.15, p. 458
© Cengage Learning 2015
Bioaccumulation vs biomagnification
© Cengage Learning 2015
End
© Cengage Learning 2015
• Scientists use live laboratory animals, case reports of poisonings, and epidemiological studies to estimate the toxicity of chemicals, but these methods have limitations
• Many health scientists call for much greater emphasis on pollution prevention to reduce our exposure to potentially harmful chemicals
17-4 How Can We Evaluate Chemical Hazards?
© Cengage Learning 2015
• Toxicology – study of harmful effects– Dose – Age– Genetic makeup – Multiple chemical sensitivity (MCS) – Solubility – Persistence – Biomagnification
Many Factors Determine the Harmful Health Effects of Chemicals
© Cengage Learning 2015
• Response– Acute effect – immediate or rapid– Chronic effect – permanent or long-lasting
Many Factors Determine the Harmful Health Effects of Chemicals (cont’d.)
Fig. 17.16, p. 459
Water pollutant levels
Soil/dust levels
Air pollutant levels
Food pesticide levels
Nutritional health
Overall health
Scientific measurements and modeling
?
LifestylePredicted level of toxicant in peoplePersonal habits
Genetic predisposition
MetabolismAccumulationExcretionLung, intestine,
and skin absorption rates
© Cengage Learning 2015
AGENDA October 29, 2014
• Wrap up toxicology/risk chapter with notes• TEST Friday (Ch 14, p156C, p385B)• Wrap up duckweed lab. Due Tue• Set up daphnia dilutions for Friday
© Cengage Learning 2015
• Analysis of umbilical cord blood– 180 chemicals found that cause cancers in
humans or animals
• Infants and children more susceptible – Less well-developed immune systems and
body detoxification processes
• Fetal exposure may increase risk of autism, asthma, learning disorders
Case Study: Protecting Children from Toxic Chemicals
© Cengage Learning 2015
• Mice and rats– Systems are similar to humans– Small, and reproduce rapidly
• Dose-response curve – median lethal dose (LD50) :LD50 is the dose of toxins needed to kill 50% of population– Nonthreshold dose-response model– Threshold dose-response model
Scientists Use Live Lab Animals and Non-animal Tests to Estimate Toxicity
© Cengage Learning 2015
• More humane methods using animals– Replace animals with other models
• Computer simulations• Tissue culture and individual animal cells• Chicken egg membranes
• What are the effects of mixtures of potentially toxic chemicals?
Scientists Use Live Lab Animals and Non-animal Tests to Estimate Toxicity (cont’d.)
Fig. 17.17, p. 460
Perc
enta
ge o
f pop
ulat
ion
kille
d by
a g
iven
dos
e
LD50
Dose (hypothetical units)
DOSE RESPONSE CURVE
Fig. 17-18, p. 461
Nonlinear dose-response
Linear dose-response
Effe
ct
Dose
Nonthreshold
Effe
ctDose
Threshold level
Threshold-the point where you first see a response
© Cengage Learning 2015
Let’s say that an LC50 (lethal concentration used instead of LD for dissolved toxins) study on arsenic (a poisonous element) is conducted using small fish. It is discovered that the LC50 is 50,000 ug/L (50 mg/L). What should the standards be?
Setting Concentration Standards for Wildlife and Humans
© Cengage Learning 2015
The Standard for Wildlife is set at one-tenth of the LC50 or LD50.
50,000 ug/L divided by 10 = 5,000 ug/L (5 mg/L) of arsenic.
The Standard for Wildlife
© Cengage Learning 2015
The Standard for Humans is set at one-hundredth of the LC50 or LD50.
50,000 ug/L divided by 100 = 500 ug/L (0.5 mg/L)of arsenic.
The Standard for Humans
© Cengage Learning 2015
The extra safe Standard for Humans is set at one-thousandth of the LC50 or LD50.
50,000 ug/L divided by 1000 = 50ug/L (0.05 mg/L)of arsenic.
Usually an extra safety factor of 10 is incorporated into standards for humans
© Cengage Learning 2015
• Case reports and epidemiological studies• Limitations of epidemiological studies
– Too few people tested– Length of time– Result linked to chemical– Cannot be used for new hazards
There Are Other Ways to Estimate the Harmful Effects of Chemicals
© Cengage Learning 2015
• Insufficient data for most chemicals• We are all exposed to toxic chemicals
– Trace amounts
• Difference between increasing dangers and better testing
Are Trace Levels of Toxic Chemicals Harmful?
AsbestosSource: Pipe insulation, vinylceiling and floor tilesThreat: Lung disease, lung cancer (mesothelioma)
Carbon monoxideSource: Faulty furnaces,unvented gas stoves andkerosene heaters,woodstovesThreat: Headaches,drowsiness, irregularheartbeat, death (binds to hemoglobin)
Methylene chlorideSource: Paint strippers and thinnersThreat: Nerve disorders, diabetes
Tobacco smokeSource: CigarettesThreat: Lung cancer, respiratoryailments, heart disease (85%lung cancer)
Radon-222Source: Radioactive gas from soil and rock surroundingfoundation, water supplyThreat: Lung cancer
Benzo-α-pyreneSource: Tobacco smoke,woodstovesThreat: Lung cancer
VOC(volatile organic compoundsIe: Styrene)Source: Carpets,plastic productsThreat: Kidney andliver damage
FormaldehydeSource: Furniture stuffing,paneling, particleboard,foam insulationThreat: Irritation of eyes,throat, skin, and lungs;nausea; dizziness
(VOCs)TetrachloroethyleneSource: Dry-cleaningfluid fumes on clothesThreat: Nerve disorders,damage to liver andkidneys, possible cancer
Para-dichlorobenzeneSource: Air fresheners,mothball crystalsThreat: Cancer
ChloroformSource: Chlorine-treated water inhot showersPossible threat: Cancer
1,1,1-TrichloroethaneSource: Aerosol spraysThreat: Dizziness,irregular breathing
Nitrogen oxidesSource: Unvented gasstoves and keroseneheaters, woodstovesThreat: Irritated lungs,children's colds,Headaches/asthma
Particulates (PM10)Source: Pollen, petdander, dust mites,cooking smoke particlesThreat: Irritated lungs,asthma attacks, itchyeyes, runny nose,lung disease
Stepped ArtFig. 17-19, p. 462
Lead (Pb) Source: pipes/paintsThreat: Brain/kidney damage
© Cengage Learning 2015
• limitations in estimating toxicity levels and risks • Only 2% of 100,000 chemicals have been adequately tested• 99.5% of chemicals used in the United States are not
supervised by government• Food Drug Administration• Environmental Protection Agency• Toxic Substance Control Act• Federal Hazardous Substances Act (labels)• HAZMAT (transportation)• CERCLA (response)• Nuclear Waste Policy Act (disposal)• OSHA
Why Do We Know So Little about the Harmful Effects of Chemicals?
© Cengage Learning 2015
• END
© Cengage Learning 2015
• Precautionary principle– Those introducing a new chemical or new
technology need to follow new strategies• A new product is considered harmful until it can be
proved to be safe• Existing chemicals and technologies that appear to
cause significant harm must be removed
• 2000 – global treaty to ban or phase out the dirty dozen persistent organic pollutants (POPs)
• 2007 REACH program in the European Union
Why Do We Know So Little about the Harmful Effects of Chemicals? (cont’d.)
© Cengage Learning 2015
• The 3M Company– 1975 to 2008, prevented more than 1.5 million
tons of pollutants from reaching the environment
– Employee reward program
Case Study: Pollution Prevention Pays
© Cengage Learning 2015
• We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices
17-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them?
© Cengage Learning 2015
• Poverty– Greatest health risk by far– Malnutrition, increased infectious disease,
unsafe drinking water
• Gender– Being born male
• Lifestyle choices– Overeating, smoking, etc.
The Greatest Health Risks Come from Poverty, Gender, and Lifestyle Choices
© Cengage Learning 2015Fig. 17-20, p. 465
Cause of death Annual deaths
Poverty/malnutrition/ disease cycle 11 million (150)
Tobacco 6.0 million (82)
Pneumonia and flu 3.2 million (44)
Air pollution
HIV/AIDS
Diarrhea 1.6 million (22)
Tuberculosis 1.4 million (19)
Automobile accidents 1.2 million (16)
Work-related injury and disease 1.1 million (15)
Malaria 1.0 million (14)
Hepatitis B
Measles 139,000 (2)
3.2 million (44)
1.7 million (23)
655,000 (9)
© Cengage Learning 2015Fig. 17-21, p. 466
Lack of access to
Number of people(% of world’s population)
Adequate sanitation facilities
Enough fuel forheating and cooking
Electricity
Adequate health care
Adequate housing
Enough food for good health
Clean drinking water
2.6 billion (37%)
2 billion (28%)
1.1 billion (15%)
1 billion (14%)
925 million (13%)
880 million (12%)
2 billion (28%)
© Cengage Learning 2015
• Most preventable major cause of suffering and premature death– Killed 100 million people during the 20th
century– Could be linked to increased dementia and
Alzheimer’s disease
• Nicotine – additive• What are the effects of passive smoking
(secondhand smoke) ?
Case Study: Death from Smoking
© Cengage Learning 2015
• How to reduce smoking– Taxes– Classify and regulate nicotine– Bans on smoking in public places– Education
Case Study: Death from Smoking (cont’d.)
© Cengage Learning 2015
• Reliability– System reliability (%) = Technological
reliability (%) x Human reliability (%)
• Human reliability is much lower than technological reliability– Much harder to predict
Estimating Risks from Technologies Is Not Easy
© Cengage Learning 2015
• Five factors can cause misjudgments in risk:– Fear– Degree of control– Whether a risk is catastrophic or chronic– Optimism bias– Instant gratification
Most People Do a Poor Job of Evaluating Risks
© Cengage Learning 2015
• Compare risks• Determine how much you are willing to
accept • Evaluate the actual risk involved• Concentrate on evaluating and carefully
making important lifestyle choices
Certain Principles Can Help Us Evaluate and Reduce Risk
© Cengage Learning 2015
• We face significant hazards from:– Infectious diseases
• Flu, AIDS, tuberculosis, diarrheal diseases, and malaria
– Exposure to chemicals that can:• Cause cancers and birth defects,• Disrupt the human immune, nervous, and
endocrine systems
Three Big Ideas
© Cengage Learning 2015
• Because of the difficulty of evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention
• By becoming informed, thinking critically about risks, and making careful choices, we can reduce the major risks we face
Three Big Ideas (cont’d.)
© Cengage Learning 2015
• Mercury is highly toxic• We can reduce some threats
– Shift to renewable sources of energy– Cutting resource use and wastes– Mimic biodiversity
• Use diverse strategies for solving environmental and health problems
Tying It All Together: Mercury’s Toxic Effects and Sustainability
© Cengage Learning 2015
• Many people have latent TB– 1.4 million deaths each year, primarily in less-
developed countries
• Why is tuberculosis on the rise?– Not enough screening and control programs– Genetic resistance to a majority of effective
antibiotics– Person-to-person contact has increased– AIDS individuals are very susceptible to TB
Case Study: The Growing Global Threat from Tuberculosis
Fig. 17-5, p. 445
© Cengage Learning 2015Fig. 17-6, p. 446
© Cengage Learning 2015
• Influenza or flu virus– Kills the most worldwide
• HIV– Infects about 2.5 million people yearly
• Hepatitis B virus (HBV)• Emergent diseases – West Nile virus
Viral Diseases and Parasites Kill Large Numbers of People
© Cengage Learning 2015
• Viruses that move form animals to humans– West Nile virus– The new field of ecological medicine
• Reduce chances of infection – Wash your hands– Avoid touching your face– Avoid sick people
Viral Diseases and Parasites Kill Large Numbers of People (cont’d.)
© Cengage Learning 2015
• Acquired immune deficiency syndrome (AIDS) – Caused by human immunodeficiency virus
(HIV)– Many secondary infections
• No vaccine to prevent or cure AIDS• Expensive drugs – live longer
Case Study: The Global HIV/AIDS Epidemic
© Cengage Learning 2015
• 30 million deaths between 1981-2012– Kills about 1.7 million people yearly
• Most prevalent in sub-Saharan Africa– Life expectancy dropped from 62 to 47– Alters age structure of population
Case Study: The Global HIV/AIDS Epidemic (cont’d.)
© Cengage Learning 2015
• Malaria– Caused by parasite carried by certain
mosquitoes – Tropical and subtropical regions– Spread
• Uninfected mosquito bites infected person, later bites an uninfected person
• Climate change – expected to spread malaria
Case Study: Malaria – The Spread of a Deadly Parasite
© Cengage Learning 2015
• Malaria is on the rise since 1970– Drug-resistant Plasmodium– Insecticide resistant mosquitoes – Clearing of tropical forests– AIDS patients particularly vulnerable
• What is the focus of current malaria research?
Case Study: Malaria – The Spread of a Deadly Parasite (cont’d.)
© Cengage Learning 2015Fig. 17.7, p. 451
© Cengage Learning 2015Fig. 17.8, p. 452
© Cengage Learning 2015Fig. 17.10, p. 454
Atmosphere
Crops Vegetation
Surface water HumansAnimals
Surface water
Vegetation