Living in the Environment

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• Living in the Environment
• 14th Edition
• Mrs. Dow
• Chapter 19

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Annual Deaths
Cause of Death
442,000
Tobacco use
400,000
Excess weight
101,500 (43,450 auto)
Accidents
85,000
Alcohol use
75,000 (14,200 from AIDS)
Infectious disease
55,000
Pollutants/toxins
30,600
Suicides
20,622
Homocides
Case Study The Big Killer
17,000
Illegal drug use
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Risk, probability, hazards 19.1

• Risk (measure of likelihood of suffering from a
  hazard)
• Injury, disease, economic loss, environmental
  damage
• Probability (how likely estimate)

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Risk Assessment
Risk Management
Hazard identification What is the
hazard? Probability of risk How likely is the
event? Consequences of risk What is the
likely damage?
Comparative risk analysis How does it
compare with other risks? Risk reduction How
much should it be reduced? Risk reduction
strategy How will the risk be reduced? Financial
commitment How much money should be spent?
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4 types of hazard

• Cultural (unsafe working conditions, smoking,
  diet, drugs, unsafe sex, driving, poverty)
• Chemical hazards (chemicals in air, water, soil,
  food)

• Physical hazards (radioactivity, fire,
  earthquake, hurricanes, floods)
• Biological hazards (pathogens, pollen, bees,
  snakes)

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Number of individuals affected
Very sensitive
Majority of population
Very insensitive
0
20
40
60
80
Dose (hypothetical units)
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Toxicology (19.2)

• Toxicity measures how harmful a substance is in
  causing injury, illness, or death to a living
  organism.
• Depends on theses factors

• Dose
• Amount of exposure
• Frequency of exposure
• Age size of person
• Health of detoxification system
• Your genetic makeup

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Factors affecting harm caused by a substance

• Bioaccumulation (absorbed stored _at_ higher
  levels)
• Biomagnification (toxins increase _at_ greater
  trophic levels)
• Chemical interactions (decrease or multiply
  effects of toxin)
• Antagonistic reduces effect
• Synergistic (multiplies effect

• Solubility
• Water soluble (move throughout environment)
• Oil or fat soluble (accumulate in tissues)
• Persistence (how fast they break down)

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Bioaccumulation and Biomagnification
DDT in fish-eating birds (ospreys) 25 ppm
DDT in large fish (needle fish) 2 ppm
DDT in small fish (minnows) 0.5 ppm
DDT in zooplankton 0.04 ppm
DDT in water 0.000003 ppm, Or 3 ppt
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• Acute (immediate)

• Chronic (long-lasting)
• Response (amount of health damage)

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Critical question.

• How much toxin produces a harmful response?
• It is different for each individual.

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Bodies way to reduce toxins

• 1. Break down, dilute or excrete
• 2. Enzymes can repair damage to DNA proteins
• 3. Some cells reproduce fast to replace damaged
  cells
• Benign (not spreading)
• Malignant (spreading throughout system)

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Estimating toxins

• Lethal dose
• Median lethal dose (LD50) is the amount needed to
  kill 50 of test animals within 14 day period
• Most toxic substances (EPA)
• Arsenic, lead, mercury, vinyl chloride,
  polychlorinated biphenyls

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100
75
Percentage of population killed by a given dose
50
25
LD50
0
4
8
12
16
14
10
6
2
Dose (hypothetical units)
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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
Table 19-1Page 413
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Epidemiological studies

• Compare health of people exposed to toxin vs.
  control group
• Dose-response curve
• Shows effects of various dosages of a toxic
  agent on a group of organisms

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• Limitations
• Too few people
• People are exposed to many toxins throughout
  their lives (hard to pin point one)
• Hazards from new technologies

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Animal testing

• Live animals are exposed to a dose under
  controlled situations
• 2-5 years on average
• Alternatives
• Computer simulations
• Tissue cultures

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Nonlinear dose-response
Linear dose-response
Effect
Effect
Threshold level
No threshold
Threshold
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Dose-response models

• Non-threshold dose-response model
• Dosage of a toxic chemical/radiation increases
  w/dosage
• Threshold dose-response model
• Threshold dosage must be reached before any
  detectable harmful effects occur

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Issues

• Kids vs. adults
• Controversial
• Small doses of radiation may be good?

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Chemical hazards 19.3

• Toxic chemical
• Temporary or permanent damage
• Hazardous chemical
• Flammable or explosive
• Irritates skin or lungs

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Potentially toxic agents

• Mutagens or ionizing radiation
• Changes in DNA
• Birth defects to fetus or embryo
• Teratogens
• Alcohol or thalidomide
• Carcinogens
• Cause or promote cancer

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• Immune system protects from disease harm
• Neurotoxins
• Poisons that attack nervous system

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• Endocrine system
• Releases hormones
• Control sexual reproduction
• Growth
• Learning ability
• Behavior
• Hormonally active agents (HAA)
• Act as hormone disrupters
• Exist at low levels in environment
• DDT, PCBS, herbicides

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Reality

• 2 of chemicals in use have been tested
• 99.5 of used chemicals not regulated

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Biological hazards 19.4

• Non-transmissible
• Develop slowly
• Multiple causes
• Not caused by living organism
• Do not spread from person to person
• Cancer
• Diabetes
• Asthma
• Malnutrition
• Blood vessel disorders

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• Transmissible disease
• Caused by living organism
• Can spread from one to another
• Air, water, food, body fluids, insects

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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)
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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• World Health Organization
• 30 of deaths/year cardiovascular disease
• 26 from transmissible infectious disease
• 12 non-transmissible cancers

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Bacteria

• Can transfer from resistant to nonresident
  bacteria
• Human travel spreads disease
• Doctors overuse antibiotics livestock are being
  exposed
• Overuse of pesticides gt resistant insects

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Figure 19-8Page 419
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Tuberculosis (TB)

• Kills 1.7 million/year
• Global epidemic
• Lack of screening (developing)
• Urbanization
• Resistant to most antibiotics
• AIDS weakens system, allows TB to spread
• Bacteria caused
• Early detection is key

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Current tuberculosis epidemic
Deaths per 100,000 people
lt2.5
2.5-10
10-35
35-70
70-100
100
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Viral disease

• Biggest killer is HIV
• Kills 5 million people/year
• Influenza
• Kills 1 million people/year
• Hepatitis B
• Damages liver
• Kills 1 million people/year

• Ebola
• West Nile virus
• SARS (severe acute respiratory syndrome)
• Vaccines are best prevention

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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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AIDS

• Sub-Saharan life expectancy 47 years
• To slow AIDS
• Concentrate those most likely to spread disease
  truck drivers, sex workers, soldiers
• Free HIV testing
• Mass advertising education
• Free or low-cost drugs

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Malaria

• Kills 1 million/year
• Caused by protozoan Plasmodium
• From mosquito to human
• 1950s 1960s
• Curtailed by spraying, draining marshes
• Most mosquitoes are resistant to insecticides
• Prevention best method (zinc vitamin A
  supplements)

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Figure 19-14Page 425
Anopheles mosquito (vector) in aquatic breeding
area
eggs
adult
larva
pupa
The Life Cycle of malaria
1. Female mosquito bites infected
human, ingesting blood that contains Plasmodium ga
metocytes
4. Parasite invades blood cells, causing malaria
and making infected person a new reservoir
2. Plasmodium develops in mosquito
3. Mosquito injects Plasmodium sporozoites into
human host
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Malaria
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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Dengue Fever
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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Yellow Fever
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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Reducing infectious diseases

• High in developing countries
• 10 of medical research for infectious disease
• Costly to research vaccines
• 1/3 of world lack clean water

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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 campain to reduce
HIV/AIDS
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Bioterrorism

• Warfare agents cheap easy to make
• Recombinant DNA makes stronger
• Concealed in small vials

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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 19.5

• Involves identifying hazards evaluating their
  risks
• Strongest risk poverty
• Reduce poverty!

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Cause of Death
Annual Deaths
11 million (75)
Poverty/malnutrition/ disease cycle
Tobacco
5 million (34)
Pneumonia and flu
3.2 million (22)
Air pollution
3 million (21)
HIV/AIDS
3 million (21)
1.9 million (13)
Diarrhea
TB
1.7 million (12)
Auto accidents
1.2 million (8)
1.1 million (8)
Work-related injury and disease
1 million (7)
Malaria
1 million (7)
Hepatitis B
800,000 (75)
Measles
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Figure 19-19Page 430
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