Environmental Health: Risk, Toxicology, and Human Health

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Environmental Health Risk, Toxicology, and
Human Health
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Key Concepts

• Hazards people face

• Defining and measuring toxicology

• Chemical hazards

• Biological hazards

• Risk estimation, management, and reduction

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Risk and Probability

• Risk

• Riskassessment

• Riskmanagement

• Probability

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Hazards

• Cultural hazards

• Physical hazards

• Chemical hazards

• Biological hazards

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Hazards
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Toxicology

• Toxicity

• Dosage

• Bioaccumulation

• Biomagnification

• Synergism

• Response

• Acute effect

• Chronic effect

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Toxicology
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Toxicology
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Poisons

• Poison

• Median lethal dose (LD50)

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Dose-Response Curves

• Dose-response

• Nonthreshold

• Threshold

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Table 9-1 Toxicity Ratings and Average Lethal
Doses for Humans
Toxicity Rating Supertoxic Extremely
toxic Very toxic Toxic Moderately
toxic Slightly toxic Essentially nontoxic
LD50 (milligrams per kg of body weight) Less
than 0.01 Less than 5 550 50500 5005,000 5
,00015,000 15,000 or greater
Examples Nerve gases, botulism toxin, mushroom
toxins, dioxin (TCDD) Potassium cyanide, heroin,
atropine, parathion, nicotine Mercury salts,
morphine, codeine Lead salts, DDT, sodium
hydroxide, sodium fluoride, sulfuric acid,
caffeine, carbon tetrachloride Methyl (wood)
alcohol, ether, Phenobarbital, amphetamines
(speed), kerosene, aspirin Ethyl alcohol, Lysol,
soaps Water, glycerin, table sugar
Average Lethal Dose Less than 1 drop Less
than 7 drops 7 drops to 1 teaspoon 1 teaspoon
to 1 ounce 1 ounce to 1 pint 1 pint to 1
quart More than 1 quart
Dosage that kills 50 of individuals
exposed Amounts of substances in liquid form at
room temperature that are lethal when given to a
70.4-kg (155-pound) human
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Chemical Hazards

• Hazardous chemicals

• Mutagens

• Teratogens

• Carcinogens

• Neurotoxins

• Hormonally active agents

• Precautionary principle

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Endocrine Mimics
Hormone
Estrogen-like chemical
Anti-androgen chemical
Receptor
Cell
Normal Hormone Process
Hormone Mimic
Hormone Blocker
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Biological Hazards Diseases

• Nontransmissible disease

• Transmissible disease

• Pathogens

• Vectors

• Tuberculosis

• HIV/AIDS

• Malaria

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Malaria
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(No Transcript)
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Painful and sometimes fatal. Carried by four
related viruses and strikes during rainy season.
2.5 million people at risk 50 million new cases
a year.
Dengue Fever
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Endemic in more than 100 countries. Caused by
four protozoa species. 270500 million new cases
and 1 million deaths per year.
Malaria
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Dreaded far more than 400 years. Viral disease
that causes symptoms from mild to severe illness
and death. 200,000 new cases and 30,000 deaths a
year.
Yellow Fever
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HIV Virus
Genetic material
Surface proteins
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The virus attaches to the host cell. The entire
virus may enter or it may inject its genetic
material, or genome.
Virus
Cell membrane
Host cell
The viral genetic material uses the host cell's
DNA to replicate again and again.
Each new copy of the virus directs the cell to
make it a protein shell.
New viruses
The new viruses emerge from the host cell capable
of infecting other cells. This process
often destroys the first cell.
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Deaths per year
Disease (type of agent)
Pneumonia and flu (bacteria and viruses)
3.2 million
HIV/AIDS (virus)
3.0 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
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Deaths per 100,000 people
lt2.5
2.5-10
10-35
35-70
70-100
100
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100 95-99 90-94 85-89 80-84 75-79 70-74 65-69 60-
64 55-59 50-54 45-49 40-44 35-39 30-34 25-29 20-24
15-19 10-14 5-9 0-4
With AIDS
Without AIDS
Male
Female
Age
20
100
120
80
60
40
120
40
20
0
60
80
10
Population (thousands)
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Hazard
Shortens average life span in the United States by
Poverty
7-10 years
Born male
7.5 years
Smoking
6-10 years
Overweight (35)
6 years
Unmarried
5 years
2 years
Overweight (15)
Spouse smoking
1 year
Driving
7 months
Air pollution
5 months
Alcohol
5 months
Drug abuse
4 months
Flu
4 months
AIDS
3 months
Air Pollution
2 months
Drowning
1 month
Pesticides
1 month
Fire
1 month
Natural radiation
8 days
5 days
Medical X rays
Oral contraceptives
5 days
Toxic waste
4 days
Flying
1 day
Hurricanes, tornadoes
1 day
Living lifetime near nuclear plant
10 hours
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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 Careful hand washing
by all medical personnel Immunize children
against major viral diseases Oral rehydration
for diarrhea victims Global campaign to reduce
HIV/AIDS
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Bioterrorism

• Possible targets air, water, and food
• Inexpensive
• Fairly easy to produce biological agents
• Recombinant DNA techniques

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Agent Smallpox (virus) Hemorrhagic fever
(viruses) Inhalation anthrax (bacterium) Botuli
sm (bacterium) Pneumonic plague (bacterium) Tu
laremia (bacterium)
Contagious Yes Yes No No Yes No
Symptoms Fever, aches, headache, red spots on
face and torso Vary but include fever, bleeding,
shock, and coma Fever, chest pain,
difficulty breathing, respiratory
failure Blurred vision, progressive paralysis,
death within 24 hours if not treated High fever,
chills, headache, coughing blood,
difficulty breathing, respiratory failure Fever,
sore throat, weakness, respiratory stress,
pneumonia
Mortality (if untreated) 30 Varies 90100
60100 90100 3060
Existence of vaccine Yes No Yes Yes No
Yes (in testing)
Treatment Vaccination within 4 days
after exposure, IV hydration Ebola has no cure,
antiviral riboflavin and some antibiotics may
help Early treatment with Cipro and other
antibiotics Equine antitoxin given
early. Intensive care, respirator Antibiotics
Antibiotics
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Risk Analysis

• Risk analysis

• Comparative risk analysis

• System reliability

• Risk management

• Risk perception

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Risk Analysis
Comparative Risk Analysis
Most Serious Ecological And Health Problems

• High-Risk Health Problems
• Indoor air pollution
• Outdoor air pollution
• Worker exposure to industrial
• or farm chemicals
• Pollutants in drinking water
• Pesticide residues on food
• Toxic chemicals in consumer products
• High-Risk Ecological Problems
• Global climate change
• Stratospheric ozone depletion
• Wildlife habitat alteration and destruction
• Species extinction and loss of biodiversity

• Medium-Risk Ecological Problems
• Add deposition
• Pesticides
• Airborne toxic chemicals
• Toxic chemicals, nutrients, and sediment
• in surface waters

• Low-Risk Ecological Problems
• Oil spills
• Groundwater pollution
• Radioactive isotopes
• Acid runoff to surface waters
• Thermal pollution