Transcript Semester 2 - Grayslake North High School

Risk, Toxicology
and
Human Health
AP Environmental Science
Chapter 8
Love Canal
•Love Canal in Niagara Falls, NY
• Love Canal Tragedy
DDT – Miracle Invention!
• What is DDT?
Dichlorodiphenyltrichlo
roethane
• Insectide
• Used to kill malariacarrying mosquito.
Kermit to Kermette
• DDT is the most wonderful new
chemical!
• DDT spraying on neighborhoods to
get rid of mosquitoes
Predator Birds Eggshells
Consequences of using DDT
• Can slow down growth in
photosynthetic algae
• Thinning eggshells of
predator birds-populations
declining
• Stays in environment for
up to 150 yrs.
Toxins are threat to living organisms
• Bioaccumulation: The amount of
• Toxic substances that accumulate in
the fatty tissues of living orgs. Not
water soluble and cannot be excreted
from body.
Examples of Toxic Substances
•
•
•
•
•
•
•
• How do organisms take up
Mercury
the toxic substances?
Lead
Fungicides
• Autotrophic—Passive
Pesticides
absorption
Herbicides
PCB’s
• Heterotrophic: Through
POP’s (persistent organic
food chain/web. More
pollutants)
dangerous levels
accumulate.
Bioaccumulation
Toxins are threat to living organisms
• Biomagnification: The accumulation
of toxic substances from the lower
levels of the food web to the top
predator, each time
magnifying/accumulating in the fatty
tissue of living orgs.
How much?
• A study in 1968 showed that Americans
were consuming an average of 0.025
milligrams of DDT per day!
• At concentration above 236 mg DDT per
kg of body weight, you'll die.
• Concentration of 6-10 mg/kg leads to such
symptoms as headache, nausea, vomiting,
confusion, and tremors.
Human Health
• Health is a state of complete physical,
mental, social and spiritual well-being
and not merely the absence of disease
or infirmity (disability)
or
• The ability to lead a socially and
economically productive life
Holistic Concept of Health
• This concept recognizes the strength of social,
economic, personal freedom and
environmental influences on health
• Determinants
–
–
–
–
–
Heredity
Health and family welfare services
Environment
Life-style
Socio-economic conditions
Disease
• Disease results from the complex
interaction between man, an agent
and the environment
• Ecological point of view –
“maladjustment of the human
organism to the environment”
Epidemilogical Triad
Any Environment
Vector (how infected: water,
pollution, insect, contact)
Pathogen:
(Virus/bacteria, protist) (Organism)
Agent
Host
Key Concepts
• Types of Hazards
• Exposure Assessment
• Risk estimation, management, and
reduction
Types of Hazards
• Biological Hazards
– These are living organisms or their
products that are harmful to humans
Biological Hazards
• Water-borne diseases
– Transmitted in drinking water
• Disease organisms shed into water in
feces
• Can produce illness in those who
consume untreated, contaminated water
Biological Hazards
• Water-borne diseases
– municipal water treatment facilities
are usually able to purify water
• removing these agents by filtration
• killing them by disinfection
Biological Hazards
• Water-borne diseases
– Examples
• Polio virus
• Hepatitis A virus
• Salmonella
• Shigella
• Cholera
• Amoebic dysentery
• Giardia
• Cryptosporidium
E. coli outbreak in Walkerton
• In May 2000 the small community of
Walkerton, Ontario was laid waste by a toxic
strain of E. coli:0157.
– The contamination came from the public water
supply.
– Six people died in the first week including a two
year old daughter of a local medical doctor.
– Four new cases surfaced in late July, all very
young children.
– Over a thousand innocent people were infected.
bss.sfsu.edu/ehines/geog600/
Freshwater%20and%20ocean%20Pollution.ppt
Waterborne Bacteria
• Disease symptoms usually are
explosive emissions from either end of
the digestive tract
Escherichia coli
Vibrio sp.
Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio
Waterborne Protozoans
• Disease symptoms are usually explosive
emissions from either end of the digestive
tract
*P. Darben
Giardia sp.*
Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio
Waterborne
Human Viruses
Hepatitis A virus
Norwalk virus*
Hepatitis E virus
Rotavirus*
*F. Williams
Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio
Indicator Tests
Total coliform
[Endo agar]
Fecal coliform
[m-FC agar]
Fecal streptococci
[M-enterococcus]
Prescott et al., Microbiology
Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio
Case Study on Eradicating
Dracunculiasis
Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward
Guinea Worm Disease
• People have suffered from Guinea Worms for
centuries – the “fiery serpent” was mentioned
in the bible
• People are infected by drinking water that
contain the larvae in a tiny freshwater
crustacean called Cyclops
• A year later, larvae mature into 3 feet worms
that emerge through skin blisters
• This is such a painful process that men and
women can’t work, children can’t attend
school
Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward
http://www.pmeh.uiowa.edu/fuortes/63111/GUINEA/
The Guinea
Worm grows
down the leg
and its sex
organs appear
at the ankle or
on the foot
usually,
bursting when
it senses water,
releasing ova.
Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward
• No vaccine for Guinea
worm is available.
• People do not seem to
build up any resistance
and the disease can be
reinfected over and
over.
• No research is being
conducted for any
vaccine or cure.
• Worms are removed
slowly each day by
winding around a stick.
http://www.pmeh.uiowa.edu/fuortes/63111/GUINEA/
Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward
Biological Hazards
• Food–borne diseases
– To protect against food-borne disease
• local health departments
–inspect
» food service establishments (restaurants)
» retail food outlets (supermarkets)
» processing plants
–verify that food
» stored
» handled properly
Biological Hazards
• Food-borne diseases
– Examples
• Salmonella, serotype enteritidis
–Eggs or undercooked chicken
–Reptiles
• Escherichia coli 0157:H7
–Spinach
–Undercooked meat
» Jack in the Box
Biological Hazards
• Vector-borne diseases
– Transmitted by insects, other
arthropods and other animals
including humans
– Improper environmental
management can cause vectorborne disease outbreaks
Biological Hazards
• Vector-borne diseases
– Examples
• Mosquitoes
–Malaria
–St. Louis encephalitis
–La Crosse encephalitis
–West Nile Virus
• Fleas
–Bubonic plague
– Murine typhus
Anopheles mosquito (vector)
in aquatic breeding area
eggs
larva
pupa
adult
1. Female
mosquito bites
infected human,
ingesting blood
that contains
Plasmodium
gametocytes
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
Areas in which malaria has
disappeared, been eradicated,
or never existed
Areas with limited risk
Areas where malaria
Transmission occurs
Fig. 16.10, p. 409
Biological Hazards
• Vector-borne diseases
– Examples
• Humans
–SARS
–Tuberculosis
–HIV
–Gonorrhea
–Syphilis
–Chlamydia
–Etc.
Deaths per
100,000 people
<2.5
2.5-10
10-35
35-70
70-100
100+
Tuberculosis epidemic, kills about 2
million people a year.
Biological Hazards
• Vector-borne diseases
– Greatest viral health threat to
human life are virulent flu strain
• 1918 Swine Flu
–Killed 20 – 30 million
• Today flu kills
–1 million per year worldwide
–20,000 in the U.S.
Spread of Diseases
• Increases international travel
• Migration to urban areas
• Migration to uninhabited areas and
deforestation
• Hunger and malnutrition
• Increased rice cultivation
• Global warming
• Hurricanes and high winds
• Accidental introduction of insect vectors
• Flooding
Reducing Spread of Diseases
• Increase research on tropical diseases and
vaccines
• Reduce poverty and malnutrition
• Improve drinking water
• Reduce unnecessary use of antibiotics
• Educate people on taking antibiotics
• Reduce antibiotic use in livestock
• Careful hand washing by medical staff
• Slow global warming
• Increase preventative health care
Types of Hazards
• Biological Hazards
• Chemical Hazards
– Harmful chemicals in the air, water,
soil, and food
– Most human have small amounts of
about 500 synthetic chemicals
Hazardous Chemicals
• Methods to determine threat
–Case Studies
• MD with actual patient record
Epigenetics
• Epigentics: (epi=top)
• a set of chemical reactions that switch
parts of the genome off and on at
strategic times and locations.
Epigenetics is the study of these
reactions and the factors that
influence them.
Epigenetics (cont.)
• Genome responds to stress, diet,
behavior, toxins, & other factors that
regulate gene expression.
• Epigenetics Introduction
• Epigenetics and gene control
Love Canal
• Love Canal
• Love Canal Part 2
Case Studies
In-depth, longitudinal examination of a single
instance or event
• 18 year- old, 5-8, 145 pound healthy male
– Circumstances
• Collapsed on 2/4/07 at 4:30 PM while in the kitchen
• Ambulance rushed him to VHH where he died of cardiac
arrest a little after 5 PM
• Toxicology results – negative
• Brain Aneurysm
– History
• Broken neck at age 7
• Hit by car June of 2005
Pesticide Effects
• http://www.pbs.org/wnet/nature/epis
odes/frogs-the-thin-green-line/videoagricultures-effect-on-frogs/4848/
• The effect of atrazine on amphibians
and eventually humans.
Hazardous Chemicals
• Methods to determine threat
– Case Studies
• MD with actual patient record
–Epidemiology
• Health officials investigating case studies
Epidemiology
• Study of the distribution and causes of
disease in populations
– how many people or animals have a disease
– the outcome of the disease (recovery, death,
disability, etc.)
– the factors that influence the distribution
and outcome of the disease
Epidemiology of Rabies
• In 2001, 49 states, the District of
Columbia, and Puerto Rico reported 7,437
cases of rabies in animals and no cases in
humans to CDC
• The total number of reported cases
increased by 0.92% from those reported in
2000 (7,369 cases)
Epidemiology of Rabies
• Wild animals accounted for 93% of
reported cases of rabies in 2001
• Outbreaks of rabies infections in
terrestrial mammals like raccoons,
skunks, foxes, and coyotes are found
in broad geographic regions across the
United States
Epidemiology of Rabies
Geographic boundaries of currently
recognized reservoirs for rabies in
terrestrial mammals
Epidemiology of Rabies
• Domestic species accounted for 6.8%
of all rabid animals reported in the
United States in 2001
• The number of reported rabid
domestic animals decreased 2.4%
from the 509 cases reported in 2000 to
497 in 2001
Epidemiology of Rabies
• Successful vaccination programs that
began in the 1940s caused a decline in
dog rabies in this country
• But, as the number of cases of rabies
in dogs decreased, rabies in wild
animals increased
Epidemiology of Rabies
Human rabies
• Declined from 100 or more each year to
an average of 1 or 2 each year
• Programs
– Animal control and vaccination programs
begun in the 1940's have practically
eliminated domestic dogs as reservoirs of
rabies in the United States
– Effective human rabies vaccines and
immunolglobins have been developed
Hazardous Chemicals
• Methods to determine threat
– Case Studies
• MD with actual patient record
– Epidemiology
• Health officials investigating case studies
Toxicology
• Toxicology is the
study of the adverse
effects of chemical,
physical or biological
agents on living
organisms and the
ecosystem.
• Toxicology,
ancient in
practice, came
to be known
simplistically
as the ‘science
of poisons’.
Laboratory Investigations to Measure
Toxicity
• “The dose makes the poison.”– almost
everything is toxic at some level.
(According to Swiss scientist Paracelsus 500 years ago.)
• How do you determine if a drug or
chemical is safe to use…lab testing!
Laboratory Investigations
Animal Studies
– Populations of lab animals usually
rodents
– Measured doses under controlled
conditions
– Takes two to five years
– Costs $200,000 to $2,000,000 per
substance
• Newer methods
Laboratory Investigations
• Newer methods
– Bacteria (Transgenic experiments)
– Cell and tissue culture
• Appropriate tissue
• Stem cells
– Chicken egg membrane
Which dose is right?
• Laboratory testing on different drugs
or chemicals are done by looking at a
dose response curve.
• To determine the toxicity of a
chemical, look at dose to which 50%
of the test population is sensitive.
Percentage of population killed by a given dose
100
In case of
lethal dose
(LD), this is
called LD50.
75
50
25
LD
0
2
4
6
8
50
10
12
Dose (hypothetical units)
14
16
Fig. 8.16, p. 171
LD-50 Dose Response
• LD50 =individual dose
required to kill 50% of
test population (e.g.,
rats, fish, mice,
cockroaches).
• Standard to compare
relative toxicities of
chemicals.
• The lower the LD50
dose, the more toxic
the pesticide.
• A pesticide with an
LD50 value of 10 mg/kg
is 10 times more toxic
than a pesticide with an
LD50 of 100 mg/kg
Number of individuals affected
Different
sensitivities to
toxin to specific
populations.
Very
Sensitive
0
Majority
of population
20
40
low
Sensitivity
60
80
Dose (hypothetical units)
Fig. 8.15, p. 171
Laboratory Investigations
• Validity Challenged
– Human physiology is different
– Different species react different to same
toxins
• Mice die with aspirin
– Species can be selected depending on
physiological area
• Pigs circulatory very similar to humans
Toxicity
Toxicity
LD50
Lethal Dose
Examples
Super
< 0.01
less than 1 drop
dioxin, botulism
mushrooms
<5
less than 7 drops
heroin, nicotine
Very
5-50
7 drops to 1 tsp.
morphine, codeine
Toxic
50-500
1 tsp.
DDT, H2SO4, Caffeine
Moderate
500-5K
1 oz.-1 pt.
aspirin, wood alcohol
Slightly
5K-15K
1 pt.
>15K
>1qt.
Extreme
Non-Toxic
ethyl alcohol, soaps
water, table sugar
(LD50 measured in mg/kg of body weight)
Hazardous Chemicals
• Why so little is known of toxicity
– Only 10% of at least 75,000 commercial
chemicals have been screened
– ~2% determined to be carcinogen,
teratogen or mutagen
– >1000 new synthetic chemicals added
per year
– >99.5% of US commercial chemicals are
NOT regulated
Dose-Response Curves
Nonlinear
dose-response
Linear
dose-response
Linear
dose-response
Effect
Effect
Nonlinear
dose-response
Threshold
level
Dose
No threshold
Dose
Threshold
Fig. 16.6, p. 401
Chemical Hazards
• Hazardous Chemicals
• Mutagens
– Chemicals (and ionizing radiation) that
changes DNA or RNA in cells
Chemical Hazards
• Hazardous Chemicals
• Mutagens
–Teratogens
• Chemicals, radiation, or viruses that cause
birth defects while the human embryo is
gestating, especially in the first three
months
Teratogens
• Examples:
– Rubella
– Mercury in water
– Fetal alcohol syndrome
– Crack babies
– Methamphetamine
Ocean Pollution: Mercury and
Minamata Disease
• Mercury has many
industrial uses but is
extremely toxic
• A chemical plant
released large
quantities of mercury
into Minamata Bay,
Japan
• http://www.youtube.
com/watch?v=LdKG1
Y2XFN0
bss.sfsu.edu/ehines/geog600/ Freshwater%20and%20ocean%20Pollution.ppt
• Residents who ate
highly contaminated
fish suffered
neurological disease
and birth disorders
Chemical Hazards
• Hazardous Chemicals
• Mutagens
– Teratogens
–Carcinogens
Carcinogens
• Causative agents
– Chemicals – Tobacco smoke
– Radiation – Pilots and cosmic radiation
– Viruses – HPV and cervical cancer
• Texas Governor mandated vaccination of
all School females with Merck’s HPV
vaccine
• Promote growth of malignant tumors
Carcinogens
• Latent Period
– Long time lapse between exposure
• Smoking
• Eating
• Lifestyle choices – laying in sun
– Symptoms
• Lung cancer
• AIDS
• Melanoma
Chemical Hazards
• Hazardous Chemicals
• Mutagens
– Teratogens
– Carcinogens
• Hormonally Active Agents
Hormonally Active Agents
• Estrogen-like chemicals
– Alter development
• Early pubescence
• Low sperm count
• Runts in wildlife
– Examples of hormone mimics
• PCB
• Organophosphates pesticides
• Industrial solvents
Hormone
Estrogen- like chemical
Antiandrogen chemical
Receptor
Cell
Normal Hormone
Process
Normal Mimic
Hormone Blocker
Hormone
Estrogen- like chemical
Antiandrogen chemical
Receptor
Cell
Normal Hormone
Process
Normal Mimic
Hormone Blocker
Hormone
Estrogen- like chemical
Antiandrogen chemical
Receptor
Cell
Normal Hormone
Process
Normal Mimic
Hormone Blocker
Chemical Hazards
• Hazardous Chemicals
• Mutagens
– Teratogens
– Carcinogens
• Hormonally Active Agents
• Precautionary Principles
Precautionary Principle
• Better safe than sorry
–Two scenarios
• Assume new chemicals guilty –
Humans are not guinea pigs
• Most Chemicals not toxic and too
expensive to test
Precautionary Principle
• Better safe than sorry
–Two scenarios
• Assume new chemicals guilty –
Humans are not guinea pigs
• Most Chemicals not toxic and too
expensive to test
Precautionary Principle
• Bioaccumulation
–An increase in concentration of a
chemicals in specific organs or
tissues in organisms
Precautionary Principle
• Biomagnification
– Increase in concentration in organisms
• DDT
• PCB
• Slowly degradable, fat-soluble chemicals
– At successively higher trophic levels of
food chains or in fatty tissue
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 ppm
Types of Hazards
• Biological Hazards
• Chemical Hazards
• Physical Hazards
– Ionizing radiation, airborne particles,
equipment design, fire, earthquake,
volcanic eruptions, flood, tornadoes, and
hurricanes
Physical Hazards
• Example: Radon
– Source:
• Arises naturally from decomposition of
uranium in the earth
• Occurs at dangerous levels in some
buildings and homes
– Can cause lung cancer
– Test kits available for under $20
Types of Hazards
• Biological Hazards
• Chemical Hazards
• Physical Hazards
• Cultural Hazards
–Sociological
–Psychological
Cultural Hazards
• Sociological
– result from living in a society where
one experiences noise, lack of privacy
and overcrowding
• Population growth
– Beyond carrying capacity when
environmental resources can support no
further growth
Cultural Hazards
• Psychological
– Environmental factors that produce
psychological changes expressed as
stress, depression, hysteria
Key Concepts
• Types of Hazards
• Exposure Assessment
• Methods of toxicology
• Risk estimation, management, and
reduction
Exposure Assessment
4 important considerations
1. Route
2. Magnitude
3. Duration of exposure
4. Frequency
Key Concepts
• Types of Hazards
• Exposure Assessment
• Risk estimation, management,
and reduction
Risk Analysis
• How can risks be estimated, managed
and reduced?
Risk Analysis involves…
•
•
•
•
Identifying hazards
Evaluate risks
Ranking risks
Determining options and
deciding course of action
• Informing policy makers and
public about risks
Risk Analysis
Risk
The possibility of suffering harm from a hazard
that can cause injury, disease, economic loss, or
environmental damage.
Risk is Expressed in terms of probability, a
mathematical statement about How likely it is
that some event or effect will occur.
Risk=Exposure X Harm
Fig. 16.2, p. 297
Risk
probability
Risk
assessment
Risk
severity
Is the risk acceptable?
Cost–benefit
Acceptable if
benefits
outweigh costs
Natural
standards
Acceptable if
risk is not
greater than
those created by
natural hazard
Expressed
preferences
Acceptable if
people agree to
accept the risks
Revealed
preferences
Acceptable if
risk is not
greater than
those currently
tolerated
Fig. 16.14, p. 412
Risk Analysis Usefulness
• Organize and analyze available
scientific information
• Identify significant hazards
• Focus on areas that warrant more
research
Risk Analysis Usefulness
• Help regulators decide how money
for reducing risks should be
allocated,
• Stimulate people to make more
informed decisions about health and
environmental goals and priorities.
Risk Perception
• If chance of death is 1 in 100,000 people
are not likely to be worried or change
behavior.
• Most of us do a poor job of assessing
relative risks from hazards around us.
Risk Perception
• Most people deny the high-risk
activities they voluntarily enjoy
– Motorcycles (1 in 50)
– Smoking (1 in 300 pack a day smokers, by
65)
– Hang-gliding (1 in 2,500)
What do you think
are the highest risk
hazards in the U.S.?
Cause of Death
Deaths
Tobacco use
431,000
Alcohol use
150,000
Accidents
95,600 (42,000 auto)
Pneumonia and
Influenza
Suicides
Homicides
84,400
30,500
19,000
Hard drug use
15,000
AIDS
14,000
Fig. 16.1, p. 396
Shortens average life span
in the United States by
Hazard
Poverty
7-10 years
Born male
7.5 years
Smoking
6 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
AIDS
3 months
Drowning
1 month
Pesticides
1 month
Fire
1 month
Natural radiation
8 days
Medical X rays
5 days
Oral contraceptives
5 days
Toxic waste
4 days
Flying
1 day
Hurricanes, tornadoes
1 day
Living lifetime near
nuclear plant
10 hours
Fig. 16.15, p. 414
Yet some of these people are terrified of
dying from…
• Commercial plane crash
– 1 in 4.6 million
• Train crash
– 1 in 20 million
• Snakebite
– 1 in 36 million
• Shark attack
– 1 in 300 million
Each year 99.1% of the
people on Earth do not
die.
Average life expectancy
continues to increase.
Bibliography
1.
2.
3.
4.
5.
6.
Humayun, Ayesha, “Introductory Lecture on Environment and Health” @
http://www.publichealth.pitt.edu/supercourse/SupercoursePPT/17011-18001/17961.ppt
Bent Flyvbjerg, “Five Misunderstandings About Case-Study Research,” Qualitative Inquiry, Volume 12,
Number 2, April 2006 219-245 @
http://flyvbjerg.plan.aau.dk/Publications2006/0604FIVEMISPUBL2006.pdf
Centers for Disease Control: National Center for Infectious Disease, “Epidemiology of Rabies,” @
http://www.cdc.gov/ncidod/dvrd/rabies/Epidemiology/Epidemiology.htm
http://bss.sfsu.edu/ehines/geog600/Freshwater%20and%20ocean%20Pollution.ppt
Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio @
http://www.texastmdl.org/presentations/Pathogen Issues I final.ppt
Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward