Transcript Chapter Twenty: The Environment and Human Health

CHAPTER TWENTY: THE
ENVIRONMENT AND HUMAN
HEALTH
Section One: Pollution and Human
Health

Environmental Effects on Health
 Pollution
1.
2.

causes illness by
Directly by poisoning
Indirectly by spreading infectious diseases
People in developing countries suffer more and usually
become ill due to polluted water
Section One: Pollution and Human
Health

Toxicology

The study of the harmful
effects of substances on
organisms
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
Is the concentration of the
chemical in the environment
high enough to be harmful?
Dose: the amount of a
harmful chemical to which
a person is exposed
Dose-response curve: shows
the relative effects of
various doses of a drug or
chemical on an organism
Section One: Pollution and Human
Health

Epidemiology
the study of the spread of diseases
 Helps scientists try to trace the disease to find the origin
 Risk Assessment: an estimate of the risk posed by the
action of a substance

 What
is the chance that you will get the disease?
Section One: Pollution and Human
Health

Pollution from Natural Sources
 Some
pollutants occur naturally in the environment
 Particulates: particles in the air that are small enough to
breath into the lungs
 Ex:
dust and soot
 Heavy
metals
 Elements
like arsenic, cadmium, lead and mercury
 Occur naturally in the rocks and soil
 Dangerous in high amounts
Section One: Pollution and Human
Health

Pollution from Human Activities
Humans activities release thousands of chemicals
 Regulations made by the government have helped reduce
some pollutants
 Some scientist believe chemical pollution may be the cause
of Parkinson’s and Alzheimer’s diseases
 Burning fuels causes many health defects
 Pesticides
 Waste Disposal
 Industrial Chemicals
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
Used in building materials, carpets, cleaning fluids, and furniture
Section Two: Biological Hazards

The Environment’s Role in Disease
Pathogens: organisms that cause disease
 Host: an organism in which the pathogen lives all or part of
its life
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
Waterborne Disease
Diseases transmitted through water
 Vectors: organisms that transmit diseases
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
Cholera
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Mosquitoes
Caused by water polluted with human feces
Malaria
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Caused by parasitic protists found in mosquitoes
Section Two: Biological Hazards

Environmental Change and Disease
 Many
ways we alter the environment make it more
suitable for pathogens
 Antibiotic Resistance
 The
overuse of antibiotic has led to pathogens developing
resistance to them
Section Two: Biological Hazards

Environmental Changes and Disease

Malaria
Transmitted through mosquitoes
 Mosquitoes breed in water
 Have developed resistance to pesticides
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Emerging Viruses
AIDS and HIV
 No drugs for treatment of viruses
 Only vaccine to prevent certain viruses
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Cross-Species Transfer
Pathogens can move from one species to another
 Many diseases started in wild animals and were transferred to
humans
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