HOW TRANSMITTED TO HUMANS
SARS Transmitted directly from animals to
humans
Virus spread by respiratory droplets
(coughing, sneezing, mucus) of humans/close
person-to-person contact
METHOD FOR CONTROLLING SPREAD OF DISEASE
Not have animals and humans in close proximity Destroy
infected animals
Quarantine infected individuals/stay at home Wear facial
masks/cover mouth and nose Wash hands frequently
Note: Not sexually transmitted, blood borne, water borne, or transmitted by insect vectors
West Nile Fever
West Nile
Transmitted by bite of infected mosquito
Transmitted by blood transfusions, organ
transplants, and from mother to child during
pregnancy
Reduce the mosquito population or the chance of being
bitten. Must mention a specific method such as wearing
more clothing/physical barriers, insect repellant,
insecticides, eliminating standing water (e.g., tires,
gutters), staying indoors in early evening, screening or
mosquito netting, clearing vegetation around dwellings.
Eradicate infected birds Use biological mosquito controls
such as fish, frogs, bats, birds, Bacillus thuringiensis (Bt)
Screen blood donations, testing of pregnant women
Notes: Mosquitoes can be infected by biting an infected bird or horse. The disease cannot be transmitted
from an infected human to an uninfected human via mosquitoes. Some public health advisories suggest
direct transmission from birds/horses to humans.
Malaria Transmitted by bite of infected mosquito
Reduce mosquito population or chance of being
bitten (see scoring guidelines for West Nile Fever)
Use biological mosquito controls (fish, frogs, bats,
birds, Bt) Spray mosquito habitat with pesticides
Take prophylactic antimalarial drugs
Transmitted by blood transfusions/organ transplants
Screen blood donations
Cholera Transmitted by ingestion of water/food
contaminated with human fecal material (cholera
bacteria)
Provide sanitary collection and treatment of
sewage/black water Provide pathogen-free water
supply Implement sanitary standards in food
preparation Boil water to kill bacteria Shut down
shellfish beds
Transmitted by inadequate hand washing (direct
ingestion)
Tuberculosis Bacterium spread by respiratory
droplets (coughing, sneezing, mucus)
Increase practice of hand washing
Immunization programs Quarantine Treatment of
infected individuals with antibiotics
ENVIRONMENTAL FACTOR THAT CONTRIBUTED TO THE HOW FACTOR INFLUENCED THE INCREASED
EMERGENCE OR REEMERGENCE OF THE DISEASE
INCIDENCE OF THE DISEASE
SARS High population density of humans Human contact
with infected animals
West Nile Climate variability (El Niño, global climate
change) Decrease in populations of mosquito predators
Increase in mosquito habitat Environmental factors that
increase availability of standing water
Increased transport of products and materials providing
accidental transport of infected mosquitoes
Increased likelihood of transmission
Led to increase of mosquito population Led to an
increase in the likelihood of transmission
Introduced the mosquito (vector) to new habitats
Malaria Decreased populations of mosquito predators
Genetic resistance to pesticides
Increased mosquito population; increased
transmission
Climate variability (El Niño, global climate change)
Increased mosquito habitat; increased transmission
Habitat alteration
Increased number of breeding sites for mosquitoes
Increasing human population density
Allowed for increased transmission opportunities
Emergence of microbes resistant to anti-malarial drugs
Led to increase in potential human host population
Cholera Lack of sanitation (transport/treatment) Lack
of access to pathogen-free water
Increased transmission of pathogen
Increasing human population density Climate
variability (El Niño, global climate change) Natural
disasters (e.g., tsunamis, floods)
Tuberculosis Increased human population density
Evolution of strains of tuberculosis bacteria that are
resistant to antibiotics
Factors that increase susceptibility of human host
(immune suppressed/compromised)
Conditions became suitable for outbreak (e.g., bacterial
contamination increases, sanitation decreases)
Increased opportunities for human-to-human
transmission
Decreased ability of immune system to destroy
pathogen
Increase in international travel/commerce Immigration
from country to country Urbanization Ecosystem
disturbance in previously uninhabited areas
Deforestation in tropical regions Increased cultivation of
rice Climate change High winds or hurricanes
Accidental introduction of disease vectors Deliberate
introduction of pathogens (bioterrorism) Flooding
Natural migration of disease vectors Resistance to
antibiotics or pesticides
Explanation must match mechanism.
“the burning of coal” as the human activity releases mercury into the environment.
•
Only the first type of fossil fuel indicated in the answer will be considered. If the wrong
source is named (e.g., petroleum products) students will not earn any points in part (a).
•
“Fossil fuel” alone, while not wrong, is unacceptable because mercury is a contaminant
primarily in coal, and the document directs the student’s attention to it.
•
“power plants/industry,” indicates that coal is used.
how mercury is transported.
•
the movement of air, wind, or air currents, since “goes into the air”
•
atmospheric mercury into the water cycle,
•
washing” at the power plant as the actual source of mercury pollution must describe how the
water is transported from that site.
how mercury enters aquatic systems from the source described above.
“Aquatic systems” can include the abiotic and/or the biotic components of the system.
how mercury gets from soil to water (e.g., by erosion or leaching).
Examples are:
•
•
•
•
•
falls as dry particles into water or onto soil
falls with rain/precipitation into water or onto soil
enters water and becomes incorporated into food chains
could enter groundwater/surface water from the coal-washing process
could enter streams and rivers from groundwater
Mercury facts such as:
•
three states of mercury—particulate, elemental, and an oxidized form
•
microorganisms in the soil and water can convert inorganic mercury into an organic form,
methyl mercury, in which form it can readily enter food chains
2
Question 1 (cont’d.)
(ways that the amount of mercury released into the environment can be reduced
•
•
•
Not burning coal lowers he atmospheric Hg levels
solar and wind energy as alternatives to coal.
Coal burning filters
Reduce the amount or change the type of fossil fuel burned
•
burn higher-rank coals but with equivalent (or lower) mercury content, thereby generating
more BTUs per unit amount of coal
•
burn coal with equivalent or better rank, but with lower mercury levels
•
use another kind of fossil fuel with lower mercury content, such as natural gas
•
switch to a power-generating system (wind, solar, hydroelectric, etc.) that has a much lower or
nonexistent mercury contamination component
•
make furnaces burn more efficiently (any of a variety of methods)
Pre-combustion removal of mercury:
•
wash the coal (physical density separation or chemical cleaning)
Post-combustion removal of mercury
•
use sorbents such as activated carbon, calcium, sodium tetrasulfide, or silicates which convert
the gaseous mercury into an insoluble, thermally stable solid compound that can then be removed by
using electrostatic precipitation, wet scrubbers, baghouse, fabric filter, or other particulate removal
device (gaseous mercury must be converted before any of these other control methods can be
effective, so “scrubbing” or “filtering” alone is not enough)
•
use catalyst systems that oxidize elemental mercury, which can then be removed, by wet lime
or limestone flue gas desulfurization (FGD) systems
•
cool the flue gas and capture fly ash
3
.
Other
•
enforce the Clean Air Act, stop exempting utilities from mercury control regulations, obtain
international agreements, enact legislation to require controls, or the like (must include discussion of
any of these chosen)
•
use tax incentives or other means of encouraging voluntary reductions (must include
discussion)
•
conserve energy, reduce consumer demand, or the like (must include discussion)
Explain why there are greater health risks associated with eating large predatory fish, such as tuna and sea
bass, than from eating small nonpredatory fish.
Why is there more mercury in predatory vs. nonpredatory fish.
This explanation should be based on the idea of bioaccumulation/biomagnification and
may include concepts such as:
•
•
food chains or webs/trophic levels
mercury transfers to higher trophic levels
• the concentration of mercury increases in higher and there is a direct relationship of size, long lifespan,
and the accumulation of mercury.
For example: over the course of a lifetime, older fish have had more time to accumulate significant amounts
of mercury, regardless of their trophic level. This point also could be earned for a discussion of absorption
through the skin/gills as it is related to the accumulation of mercury over a longer lifetime
.
bioaccumulation/ biomagnification,
•
•
•
mercury is stored in fat/muscle and cannot be removed easily by body enzymes
mercury can enter food chains by being converted to methyl mercury
explains the difference between bioaccumulation and biomagnification
4
.
Effects of Lead on Human Health
menstrual problems
multiple sclerosis
muscular dystrophy
neurological effects/brain development and
function/ hostility/hypertension/learning
disorders/mental retardation/numbness Parkinson’s
disease prostate enlargement red blood
cell/anemia/enzyme function restlessness stroke
How Lead Is Introduced (read all for a
correct answer)
Industry:
mining and refining processes
Consumer goods:
batteries
cigarette smoke
coal combustion
colored inks
cosmetics
electronics
firing ranges/bullets
food (esp. candy)
gasoline additives
hair dyes
insecticides
paint
pottery glazes
plumbing
radiator repair shops
TV picture tube
toothpaste
volcanic eruptions
window blinds
wine
Effects of Lead on Human Health
abdominal pain
adrenal/liver/kidney dysfunction
allergies
anxiety
autism
birth defects/toxic to the fetus
blindness
bones/joint pain and weakness/arthritis
cardiovascular disease
colic
constipation
convulsions
depression
dizziness/headache/fatigue/nausea
dyslexia
epilepsy
GI symptoms
gout
hallucination/mood swings/nightmares/poor
concentration/psychosis
hyperactivity
immune system depression
impotence
http://www.unep.org/urban_environment/pdfs/dandorawastedump-reportsummary.pdf
http://www.lef.org/protocols/prtcl-156.shtml
Heavy Metal Toxicity
PCBs
• Ingesting seafood
contaminated with
PCBs • Inhaling dust
contaminated with
PCBs • Absorption
through skin •
Drinking contaminated
water
Mercury
• Ingesting seafood contaminated with
mercury • Ingesting food or water
contaminated by soil, mine waste or
particulates containing mercury • Inhaling
mercury vapors (from broken thermometers,
barometers, compact fluorescent lightbulbs,
etc.) • Absorption through skin • Medical and
dental procedures
Lead
• Ingesting food or water from
ceramic tableware produced with
lead-containing glazes • Ingesting
food or water contaminated by
soil, mine waste, particulates or
plumbing containing lead •
Ingesting lead-based paint •
Inhaling dust or vapors
contaminated with lead
PCBs
• Birth defects
• Nervous system damage
Mercury
• Birth defects
• Nervous system damage
• Brain damage
• Brain damage
• Learning disabilities
• Learning disabilities
Lead
• Birth defects
• Nervous system
damage
• Brain damage
• Mental retardation
• Mental retardation
• Learning disabilities
• Paralysis
• Paralysis
• Mental retardation
• Attention deficit disorder
• Damage to the reproductive
system • Feminization • Low
sperm counts • Hermaphroditism •
Cancer
• Attention deficit disorder
• Reproductive system damage
• Feminization • Low sperm counts •
Hermaphroditism • Kidney damage •
Hearing loss
• Paralysis
• Attention deficit
disorder • Kidney damage •
Hearing loss • Anemia • Liver
or stomach damage
• Minamata disease • Autism* * While
controversial, published studies have suggested a
link between mercury and autism.
Describe TWO specific steps, other than an outright ban, that a city or nation can take to reduce
the threat posed by this pollutant
PCBs
• Educate people about how to
avoid PCBs
Mercury
• Educate people about how to
avoid mercury
Lead
• Educate people about how to
avoid lead
• Substitute safer alternatives
for PCBs
• Substitute safer alternatives for
mercury
• Substitute safer alternatives
for lead
• Replace products that
contain PCBs with different
products
• Replace products that contain
mercury with different
products
• Replace products that
contain lead with different
products
• Collect and safely dispose of
products containing PCBs
• Collect and safely dispose of
products containing mercury
• Collect and safely dispose of
products containing lead
• Set and/or enforce policies
that limit the production, use
and discharge of PCBs
• Set and/or enforce policies that
limit the extraction,
production, use and discharge
of mercury
• Set and/or enforce policies
that limit the extraction,
production, use and
discharge of lead
• Phytoremediation of
contaminated areas
• Phytoremediation of
contaminated areas
• Treat water supplies to remove
mercury
• Restrict fishing for species
known to have high mercury
concentrations
• Treat water supplies to
remove lead
• Remove, cap or contain mine
waste with high mercury
concentrations
• Use technology to remove mercury
from coal and smokestacks • Reduce
coal burning • Clean up mercury
spills
• Remove, cap or contain soils
with high lead concentrations
• Phytoremediation of
contaminated areas
• Treat water supplies to
remove PCBs
• Restrict fishing for species
known to have high PCB
concentrations
• Dredge contaminated
waterways
• Wash contaminated soil
• Incinerate contaminated soil
• Remove, cap or contain mine
waste with high lead
concentrations
• Remove lead-based paint from
painted surfaces
Reasons why children are particularly susceptible to toxic pollutants
•
Children take in more water, food and air per unit of body weight than adults.
•
Children often put dirty objects or hands in their mouths.
•
Children have less developed immune systems.
•
The liver of a child does not metabolize pollutants as efficiently as the liver of an adult.
•
The growing organ systems of children are more sensitive to pollutants than the mature systems
of adults.
•
Children will accumulate pollutants for a longer period of time than adults.
Toxology
Smoking
Leading cause of death among adults in the United States is tobacco use.
Adding a $2-4 federal tax to the price of a pack of cigarettes is a form of user-pays approach.
The four main types of hazards include



biological hazards.
physical hazards.
chemical hazards.
Cultural hazards




smoking.
drugs.
diet.
unsafe sex.
biological hazards




pollen.
parasites.
bacteria.
bees.
physical hazards




hurricanes.
landslides.
ionizing radiation.
fires.
Evaluating the potential harm to humans of a particular chemical requires determining
the sources and amounts of exposure.
the amounts absorbed and distributed throughout the body.
the amount excreted.
Exposure
1. chronic exposure-A person receiving background radiation from a low-level radioactive dump
site for a lifetime has experienced
2. acute exposure -A person flying over the Chernobyl site two days after the explosion most
probably experienced
3. acute effect-.A person experiencing dizziness after using a strong household cleaner
4. chronic effect.-A person experiencing liver damage after a lifetime of alcohol abuse
5. acute effect.-A person with kidney damage after an acute exposure to a toxic chemical
Dose/Response
Dose and response may be affected by the chemical's




solubility characteristics.
biomagnification.
antagonistic and synergistic interactions with other chemicals.
persistence.
The level of threat posed by a particular substance is determined by



laboratory investigations.
epidemiology.
case studies.
Laboratory investigations involve




tests on live laboratory animals.
controlled experiments.
construction of dose-response curves.
a control group.




uncertainty about the accuracy of a threshold dose-response model.
uncertainty about the accuracy of a linear dose-response model.
that human metabolic processes differ from those of test animals.
we are going to run out of animals.
1.
2.
3.
A threshold dose-response model implies there is a dose below which no detectable harmful effects occur.
The model most often assumed because it errs on the side of safety is the linear dose-response model.
Dose-response curves are generated from laboratory studies comparing experimental and control groups of
test animals.
Dose-response curves show the effects of various doses of toxic agents on a group of test organisms.
4.
epidemiology
An epidemiological study showing a standard increase in physical effects for each rise in the dose of a toxic substance
would imply a linear dose-response curve.
The study of the pattern of a disease in a population is called epidemiology.
Epidemiological studies are limited by difficulty in establishing cause and effect because people have been exposed to
many different toxic agents.
Toxins
The principal types of chemical hazards include all of the following




toxic and hazardous substances.
mutagens.
teratogens.
carcinogens.
Toxic substances are fatal to over 50% of test animals at given concentrations.
Hazardous chemicals include




strong acids.
asphyxiants.
allergens.
strong bases.
Mutagens cause mutations.
Mutagens directly change molecules of DNA.
All of the following are expressions of harmful inheritable mutations in humans




hemophilia.
sickle-cell anemia.
manic depression.
thalasseamia.
Teratogens cause birth defects.
irth defects can be caused by



radiation.
viruses.
chemicals.
Of the following chemicals, the to cause birth defects is(are)


PCBs.
thalidomide.


steroid hormones.
heavy metals.
Carcinogens cause cancer.
Carcinogens may be
viruses.
radiation.
chemicals.
According to the World Health Organization, which of the following plays the most important role in causing or
promoting cancer? cigarette smoke
A delay of 10-40____ years between initial exposure to a carcinogen and appearance of detectable symptoms is
typical.
The system responsible for defense against disease and harmful substances is the immune system.
Two lines of defense in the human body's immune system are antibodies and cellular defenses.
The immune system can be made vulnerable to allergens, bacteria, and viruses through the action of
 some synthetic chemicals.
 ionizing radiation.
 viruses like HIV.
Specialized cells, tissues, and organs which secrete hormones are part of the endocrine system.
All of the following are synthetic neurotoxins that have been released into the environment




industrial solvents.
chlorinated hydrocarbons.
arsenic and mercury.
lead.
The system responsible for growth, reproductive development, and much of our behavior is the endocrine system.
All of the following are synthetic chemicals that can act as hormone mimics or hormone blockers




dioxins.
PCBs.
some pesticides.
DDT.
The endocrine system is disrupted by the intake of
lead.
PCBs.
dioxins.
DDT.
The intake of synthetic mimics can severely disrupt the endocrine system.
You would predict that a hormone disrupter would most effect a tertiary consumer.
You have been studying a large lake ecosystem. You learn that PCBs have been dumped into the water. You predict
that the most affected population would be the predatory birds.
Vectors are agents of disease transmission.
All of the following are transmissible diseases
 pneumonia.
 diarrhea.
 tuberculosis.
 AIDS.
Infectious and parasitic diseases cause about 26%____ of the world's deaths.
infectious diseases most deadly




acute respiratory infections
Malaria
tuberculosis
AIDS
In a developing country, you are most likely to fear health threats from unsanitary drinking water.
Outbreaks of infectious diseases often occur because of a change in the physical, social, or biological environment of
hosts.
carrier vectors.
disease reservoirs.
In which of the following situations would you predict an outbreak of an infectious disease is likely to occur?
Deforestation is rapid with large loss of biodiversity.
It's an El Niño-Southern Oscillation year.
Agriculture is spreading to more marginal land.
Disease-causing organisms can be spread by natural disasters such as
floods.
landslides.
hurricanes.
the rise in the incidence of bacterial diseases once controlled by antibiotics is the
genetic adaptability of bacteria.
spread of bacteria around the globe.
use of antibiotics in the dairy industry.
overuse of antibiotics by doctors.
In 1998, health officials warned that bacterial strains resistant to multiple antibiotics were likely to occur more
frequently unless humans improved sanitation procedures, especially hand-washing.
Tuberculosis is caused by bacteria.
The incidence of tuberculosis is increasing because
strains of the TB bacterium have developed resistance to antibiotics.
increased population size and the advanced age of the population.
weakened immune systems from the spread of AIDS.
poverty.
All of the following are viral diseases
AIDS.
ebola.
influenza.
rabies.
Each year, up to 1 in 3____ Americans suffer a food-borne illness.
About 80% of food-borne illness in the United States is caused by cyanobacter and salmonella.
Although most food in the United States is safe, there is an increasing risk of bacterial infections because of
lax inspection.
overuse of antibiotics by doctors and meat producers.
changes in meat production.
Vaccines can help prevent all of the following diseases
polio.
rabies.
measles.
mumps.
(except Aides??????)
Malaria is caused by viruses.
Malaria is spread by Anopheles mosquitoes.
All of the following are symptoms of malaria
general weakness and weakened immune system.
chills and fever.
enlarged spleen.
anemia.
During the mid-1900s, the spread of malaria decreased sharply from
draining swamplands.
draining marshes.
spraying breeding areas with DDT and other pesticides.
using drugs to kill the parasites in the bloodstream.
Incidence of malaria has increased since 1970 because
a. organisms causing malaria developed resistance to drugs.
b. the vectors developed resistance to insecticides.
c. reservoirs from hydropower have increased.
Sexually transmitted diseases (STDs) may be transmitted
from mothers to infants during birth.
by exposure to infected blood.
from one IV drug user to another when needles are shared.
An epidemiologic transition happens when mortality is caused more from chronic diseases than from infectious
diseases of childhood.
The leading causes of death in the developed countries are environmental and lifestyle factors.
The factor most responsible for illness in developed countries is diarrheal diseases.
Of the following strategies to improve health care, the one that would have the least effect on improving health care in
developing countries would be better exercise programs.
Primary preventive health care that could make significant improvements in developing countries at low cost includes
all of the following
family-planning counseling.
postnatal care.
immunization against preventable infectious diseases.
all of these answers
EPA science advisors consider all of the following to be high-risk ecological problems except
global climate change.
species extinction and loss of biodiversity.
stratospheric ozone depletion.
wildlife habitat destruction.
Pesticides, oil spills, and thermal pollution are considered by EPA science advisors to be low-risk ecological
problems.
EPA science advisors consider indoor and outdoor air pollution problems to be high-risk health problems.
All of the following are part of the process of risk assessment except
determining the types of hazards involved.
estimating how many people are likely to be exposed.
estimating the probability that each hazard will occur.
none of these answers
The major cause of a reduced human life span today is poverty.
Susceptibility to environmental stresses is increased in people already affected by
poverty.
disease.
malnutrition.