Environmental Hazards and Human Health

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Environmental Hazards and Human Health

• Chapter 14

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Core Case Study HIV/AIDS (1)

• Acquired immune deficiency syndrome (AIDS)
• Human immunodeficiency virus (HIV)
• Mode of transmittance
• Exponential increase of infection worldwide

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Core Case Study HIV/AIDS (2)

• No vaccine for HIV
• No cure for AIDS

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Kaposis Sarcoma
Fig. 14-1, p. 323
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Impact of AIDS on the Age Structure of Botswana,
Africa
Fig. 14-2, p. 323
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14-1 What Major Health Hazards Do We Face?

• Concept 14-1 People face health hazards from
  biological, chemical, physical, and cultural
  factors and from the choices they make in their
  lifestyles.

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Risk and Hazards

• Risk
• Probability
• Possibility
• Risk assessment
• Risk management

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Risk Assessment and Risk Management
Fig. 14-3, p. 324
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Major Types of Hazards

• Biological
• Chemical
• Physical
• Cultural
• Lifestyle

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14-2 What Types of Biological Hazards Do We Face?

• Concept 14-2 In terms of death rates, the most
  serious infectious diseases are flu, AIDS,
  diarrhea, and malaria, with most of these deaths
  occurring in developing countries.

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Biological Hazards (1)

• Nontransmissible diseases
• Transmissible (infectious) disease
• Pathogens
• Epidemic
• Pandemic

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Biological Hazards (2)

• Good news
• Bad news

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Pathways for Infectious Diseasein Humans
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Air
Water
Food
Insects
Wild animals
Livestock
Pets
Fetus and babies
Humans
Other humans
Fig. 14-4, p. 326
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Stepped Art
Fig. 14-4, p. 326
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Worlds Seven Deadliest Infectious Diseases
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Disease (type of agent)
Deaths per year
Pneumonia and flu (bacteria and viruses)
3.2 million
HIV/AIDS (virus)
3.0 million
Diarrheal diseases (bacteria and viruses)
2.1 million
Malaria (protozoa)
2.0 million
Tuberculosis (bacteria)
1.6 million
Hepatitis B (virus)
1 million
Measles (virus)
800,000
Fig. 14-5, p. 326
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Science Focus Growing Resistanceto Antibiotics

• High bacterial reproductive rate
• Genetic resistance
• Global travel
• Use of pesticides
• Overuse of antibiotics

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Global Threats from Disease

• Tuberculosis
• Viral diseases
• Malaria

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Distribution of Malaria
Fig. 14-6, p. 329
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The Life Cycle of Malaria
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Female mosquito bites infected human,
ingesting blood that contains Plasmodium
gametocytes
Merozoites enter bloodstream and develop
into gametocytes causing malaria and
making infected person a new reservoir
Plasmodium develop in mosquito
Sporozoites penetrate liver and develop into
merozoites
Female mosquito injects Plasmodium
sporozoites into human host.
Fig. 14-7, p. 329
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Female mosquito bites infected human, ingesting
blood that contains Plasmodium gametocytes
Merozoites enter blood-stream and develop into
gametocytes causing malaria and making infected
person a new reservoir
Plasmodium develops in mosquito
Sporozoites penetrate liver and develop into
merozoites
Female mosquito injects Plasmodium sporozoites
into human host
Stepped Art
Fig. 14-7, p. 329
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Ecological Medicine

• Zoonotic diseases
• Ecological (conservation) medicine
• Human actions encourage spread of disease
• Clear-cutting and fragmentation
• Harvesting animals
• Global trade and travel
• Trade in wild species

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Science Focus A Nightmare Flu Scenario

• Common flu
• Potent varieties of flu virus
• Spanish flu of 1918
• Future pandemics
• Animals as reservoirs for flu virus
• H5N1 avian flu virus (bird flu)

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Preventing or Reducing the Incidence of
Infectious Diseases
Fig. 14-8, p. 331
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14-3 What Types of Chemical Hazards Do We Face?

• Concept 14-3 There is growing concern about
  chemicals that can cause cancer and disrupt the
  human immune, nervous, and endocrine systems.

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Chemical Hazards (1)

• Toxic chemicals
• Hazardous chemicals
• Mutagens
• Teratogens
• Carcinogens

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Chemical Hazards (2)

• Metastasis
• Immune system
• Neurotoxins
• Hormonally active agents (HAA)
• DDT, PCBs, atrazine, aluminum, mercury,
  bisphenol-A

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14-4 How Can We Evaluate Chemical Hazards?

• Concept 14-4A Any synthetic or natural chemical
  can be harmful if ingested in a large enough
  quantity.
• Concept 14-4B Many health scientists call for
  much greater emphasis on pollution prevention to
  reduce our exposure to potentially harmful
  chemicals.

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Determining Chemical Safety (1)

• Toxicology
• Toxicity
• Dose
• Relevance of genetic makeup
• Multiple chemical sensitivity (MCS)

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Determining Chemical Safety (2)

• Water and fat soluble toxins
• Persistence
• Bioaccumulation
• Biomagnification
• Chemical interactions

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Type and Severity of Health Damage

• Response dose dependent
• Acute
• Chronic
• Mechanisms which reduce harmful effects
• Age-related effects
• Effects of trace levels of toxic chemicals

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Estimating Human Exposure to Chemicals and Their
Effect
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Water pollutant levels
Air pollutant levels
Soil/dust levels
Food pesticide levels
Nutritional health
Overall health
Lifestyle
Predicted level of toxicant in people
Personal habits
Genetic predisposition
Metabolism Accumulation Excretion
Lung, intestine, and skin absorption rates
Fig. 14-9, p. 335
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Potentially Harmful Chemicals Foundin Homes
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Teddy bear Some stuffed animals made oversees
contain flame retardants and/or pesticides
Shampoo Perfluorochemicals to add shine
Clothing Can contain perfluorochemicals
Baby bottle Can contain bisphenol-A
Nail polish Perfluorochemicals and phthalates
Mattress Flame retardants in stuffing
Perfume Phthalates
Hairspray Phthalates
Carpet Padding and carpet fibers contain flame
retardants, perfluorochemicals, and pesticides
Food Some food contains bisphenol-A
TV Wiring and plastic casing contain flame
retardants
Milk Fat contains dioxins and flame retardants
Sofa Foam padding contains flame retardants
and perfluorochemicals
Frying pan Nonstick coating contains perfluorochem
icals
Toys Vinyl toys contain phthalates
Fruit Imported fruit may contain
pesticides banned in the U.S.
Tennis shoes Can contain phthalates
Water bottle Can contain bisphenol-A
Tile floor Nonstick coating contains perfluorochem
icals, phthalates, and pesticides
Computer Flame retardant coatings of
plastic casing and wiring
Fig. 14-10, p. 336
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Protection against Harmful Chemicals

• Pollution protection
• Precautionary principle
• Persistent organic pollutants (POPs)
• The dirty dozen
• Can we have a risk-free society?

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14-5 How Do We Perceive Risks and How Can We
Avoid the Worst of Them?

• Concept 14-5 We can reduce the major risks we
  face by becoming informed, thinking critically
  about risks, and making careful choices.

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Evaluating Risks (1)

• Risk analysis (risk assessment)
• Comparative risk analysis
• Risk management
• Risk communication

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Evaluating Risks (2)

• Poverty the greatest risk
• Risks from lifestyles

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Number of Deaths Per Year in the World
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Cause of death
Annual deaths
Poverty/ malnutrition/ disease cycle
11 million (150)
Tobacco
5.4 million (74)
Pneumonia and flu
3.2 million (44)
Air pollution
3 million (41)
HIV/AIDS
3 million (41)
Malaria
2 million (27)
Diarrhea
1.9 million (26)
Tuberculosis
1.6 million (22)
Automobile accidents
1.2 million (16)
Work-related injury and disease
1.1 million (15)
1 million (14)
Hepatitis B
Measles
800,000 (11)
Fig. 14-11, p. 338
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Comparison of Risks in the United States
Fig. 14-12, p. 339
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Comparative Risk Analysis
Fig. 14-13, p. 340
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Annual Deaths in the United States from Tobacco
Use and Other Causes in 2004
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Cause of Death
Deaths
Tobacco use
442,000
101,500 (43,450 auto)
Accidents
85,000
Alcohol use
Infectious diseases
75,000 (16,000 from AIDS)
55,000
Pollutants/toxins
30,600
Suicides
Homicides
20,622
17,000
Illegal drug use
Fig. 14-14, p. 340
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Estimating Risks from Technologies

• System reliability () Technological
  reliability Human reliability
• Difficulties in estimating reliability
• Perceived risk vs. actual risk

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Improving Risk Evaluation

• Carefully evaluate news reports
• Compare risks
• Concentrate on most serious risks

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Animation HIV Replication
PLAY ANIMATION
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Animation Life Cycle of Plasmodium
PLAY ANIMATION
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Animation Formation of Photochemical Smog
PLAY ANIMATION
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Animation Thermal Invasion and Smog
PLAY ANIMATION
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Animation Positron-Emission Tomography
PLAY ANIMATION
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Video To See Again
PLAY VIDEO
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Video New Nerves
PLAY VIDEO
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Video Fat Man Walking
PLAY VIDEO
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Video Second-Chance Heart
PLAY VIDEO
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Video Regenerative Human Organs
PLAY VIDEO
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Video The Problem with Pork
PLAY VIDEO
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Video Polio Scare
PLAY VIDEO
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Video AIDS Conference in Brazil
PLAY VIDEO
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Video Bird Flu
PLAY VIDEO
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Video Beach Pollution
PLAY VIDEO
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Video Food Allergy Increase
PLAY VIDEO
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Video World AIDS Day
PLAY VIDEO
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Video Clean Air Act
PLAY VIDEO
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Video MTBE Pollution
PLAY VIDEO
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Video U.S. Earth Summit
PLAY VIDEO
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Video Frogs Galore
PLAY VIDEO