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What is the relationship between
environmental health & our own
health?
Environmental
Health is the
study of how environmental
factors affect human health & our
quality of life. Any factor that
threaten of are harmful to human
health are called hazards.
Environmental
hazards can be
biological, social, chemical or
physical.
Biological Hazards: Viruses,
bacteria, & other organisms in
the environment that cause harm
to humans are classified as
biological hazards. Pathogens
infect humans & make us sick.
Social
Hazards: Hazards that
result from where we live, our
jobs or our lifestyle choices.
Ex:
smoking-increases you risk
of lung cancer or living beside a
factory where illegal chemicals
are being released
Chemical
Hazards: Chemicals
in the environment that harm
human health. They can by
synthetic or produced by
organisms.
Ex: disinfectants to clean your
kitchen
Physical
Hazards: Physical
process that pose threat to our
health including natural
disasters. Ex: UV radiation from
sun
Epidemiology & Toxicology are
two scientific fields that help us
understand how, where & to what
extent environmental hazards
affect our health.
Epidemiology is the study of
disease in human population.
Epidemiologists are scientist that
study how & where disease
occurs & how to control them.
Toxicology is the study of how
poisonous substances affect an
organism’s health. A substance’s
toxicity determines how harmful
a substance is to an organism.
Toxicity
is determined by two
factors:
What
How
the substance is
much of the substance is
needed to cause harm
Toxicity is determined by
measuring the response a
substance produces at
different doses. A dose is the
amount of substance an
organism is exposed to. This
includes the amount & time
exposed.
The response is the effect an
organism show as a result of
exposure.
The
relationship between the
different doses & the response
they generate is called the doseresponse relationship.
Determining this relationship is
difficult in humans.
Every
person is different.
Two people can drink
contaminated water & have
two different reactions.
Below are some reasons
why people react
differently.
• Sensitivity: People with health
issues may be more sensitive
to hazards. Sensitivity can also
vary w/age, sex & weight.
Babies & older people are
more sensitive that adults.
Genetics: Many diseases
have both genetics &
environmental factors.
Environmental factors can
increase the risk of
developing the disease
Risk
Assessment is the process
of measuring the chance that an
environmental hazard will cause
harm.
1)Risk is the likelihood that that a
given hazard will cause harm.
2)The process of measuring risk is
called risk assessment.
Hazard
Annual Risk of
Death per 100,000
people
Heart Disease
271.0
Motor Vehicle Accident
Falls
Illegal drugs
Rail trespassing accidents
15.0
6.0
5.6
0.15
Being hit by a meteorite
0.04
Lightning
0.016
You
encounter biological
hazards EVERY DAY! Biological
hazards are the second leading
cause of death worldwide.
Infectious
Disease are
caused by pathogens, such
as viruses & bacteria.
Infectious diseases account
for nearly 30% of all deaths
each year.
Infectious
disease spread
through the human
population in different
ways. Pathogens can be
spread by human, water or
food, or by other
organisms.
Humans
– Some disease
can be spread directly from
one human to another. For
example: touching, biting,
or contact w/bodily fluids.
HIV
and TB are two
diseases that can be
transmitted from person
to person.
Water
or food – Some
pathogens spread when
people eat contaminated
food or drink. Cholera is
disease caused by a
bacterium in water.
It
makes people sick when they
drink the contaminated water.
The person may experience
intense diarrhea and vomiting.
You can die from the cholera.
Other
Organisms – Organism
carries the pathogen and passes
it to a person. The organisms do
not suffer from the disease but
passes on the pathogen to
humans.
Malaria
is a disease that is
transmitted by this way. A female
mosquito picks up the pathogen
& when it bites an infected
person & then transmits it when
it bites a non-infected person.
Emerging
Disease is a disease
that has appeared in the human
population for the first time or
has existed but is increasing
rapidly or spreading around the
world.
Ex:
Swine flu
Increasing
mobility – people
are more mobile so the disease
is being spread more easily
Antibiotic
resistance - bacteria
becoming resistant to the
antibiotics b/c of natural
selection.
Some
bacteria survive after
being exposed to the drug. They
reproduce & create more
bacterial resistant to the
antibiotic.
Changing
environment – When
we cut down trees, we may
come into contact w/ animals
that spread disease. Climate
change can also encourage the
spread of disease.
Social
Hazards - some can be
avoided while other cannot. You
might live near an old toxic
waste dump…a hazard difficult
to change. You may choose to eat
unhealthy foods….a change YOU
can make!
All
chemical hazards can be
dangerous in large enough
quantities. A chemical hazard
is anything that may harm
human health.
Chemical
Pollution
Hazard vs. Pollution
is matter or energy that
is released into the environment,
causing negative effects that
impact people, wildlife & other
parts of the environment
Example: oil in poison ivy. This is
a chemical hazard b/c it can
cause itchy rash on humans but
not a pollutant because it doesn’t
harm the environment.
Types
of Chemical Hazards
Chemical
hazards can cause
cancer, birth defects & improper
function of human body systems.
Carcinogens: Chemicals that
cause cancer are known
carcinogens. Cancer is a
disorder where cells grow
uncontrollably.
Cancer
does have a
genetic component but can
be influenced by
environmental factors.
• Chemical Mutagens –
are substances that cause
genetic changes or
mutations in the DNA or
an organism.
• Ex: benzene…second
hand smoke, gasoline &
air pollution
Teratogens
– are
chemicals that harm
embryos & fetuses.
Example:
alcohol
thalidomide,
Neurotoxins
– Chemicals
that affect the nervous
system. Neurotoxins are
various heavy metals such
as lead, mercury &
cadmium.
Allergens
– Substances
that over activate the
immune system causing a
response when one is not
necessary.
Examples:
mold, bacteria,
animal proteins
Endocrine
Disruptors – is
a chemical that interferes
with the endocrine system
or hormones.
Hormones
regulate our
body functions like growth
& development. Small
children are at the greatest
risk b/c they are
developing.
Example:
PCBs
Our
homes & buildings may
contain chemical hazards
including asbestos, radon,
volatile organic compounds,
carbon monoxide & lead.
Indoor pollution is not always
easy to detect
Asbestos
is a mineral that
forms long think fibers. It
is used as insulation to
muffle sounds and keep
heat in.
When
disturbed, these
fibers can be inhaled &
may go into lung tissue.
This may cause cancer &
asbestosis.
Radon
is a colorless,
odorless, highly toxic
radioactive gas. This gas is
made naturally when
uranium in rock, soil &
water decay.
Radon
is detected w/a
special kit & can be vented
out of the building.
Volatile
Organic
Compounds (VOCs) is a
diverse group of indoor
pollutants. These
chemicals contain carbon
and are released into the
air by plastics, perfumes &
pesticides.
We
are unsure how they
affect our health b/c we are
exposed to them in such
low levels. Formaldehyde
is an exception.
Carbon
Monoxide is a
colorless & odorless gas.
Low exposure can cause
headaches, nausea,
dizziness & fatigue.
Higher
exposure can
impair vision, chest pains,
lower brain function &
death. Carbon monoxide
can lead from stoves, car
exhaust & tobacco smoke.
You
can protect yourself
with a carbon monoxide
detector.
Lead
is another indoor
hazard. Lead can be in the
air, drinking water,
contaminated soil, dust &
lead-based paint.
Lead
poisoning can lead to
learning problem. When
ingested, lead poisoning
can damage the brain, liver,
kidneys & stomach.
Hazardous Waste
is waste
with characteristics that
make it harmful to human
health and the
environment

CORROSIVE
• Chemical action can burn
or destroy living tissue &
other material brought
into contact
Ignitable, flammable,
or combustible
• Easily set on fire
Explosive-
explode
when exposed to
heat, sudden shock,
pressure or certain
chemical substance
Toxic
- Hazardous
substance that causes
adverse effects to living
things or environment
Less toxic
More toxic
CAUTION
Mild hazard
Warning
Moderate
hazard
DANGER
POISON
Extremely
toxic,
flammable,
corrosive
There
are chemical
hazards in the air, on land,
and in the water.
These
contaminants include
antibiotics, detergents,
drugs, disinfectants,
solvents, perfumes and
other substances.
Hazards
in the air –
Chemicals in the air can
travel by wind & impact an
area far away from the
beginning point.
Volcanic
eruptions &
human activity can release
chemical hazards in the
air….such as carbon
monoxide, sulfur dioxide,
etc.
Hazards
on Land –
Chemical hazards can
enter the soil in many ways.
Using pesticides put
chemicals directly in the
land.
Also
improper disposal of
electronic devices can add
heavy metals like lead in
the soil
Hazards
in Water – Many
chemicals are soluble in
water and enter the
organisms’ tissues through
drinking or absorption.
Chemicals
can enter the
water in many different
ways. Runoff…water runs
off the land & picks up
everything in its path.
Hazards
can also be
released directly into the
water.
Toxic
chemicals
accumulate in organisms as
they feed on one
another…this is called
biomagnification!
When
the toxic substance
builds up large
concentrations in the
bodies of organisms it is
called bioaccumulation
Persistent
Organic
Pollutants (POPs) are the
chemicals that magnify
through the food web &
cause adverse health
effects for humans.
POPs
can be carried long
distances by water & wind.
Ex.
DDT, PCBs
The
use of POPs has led to
an international treaty.
As
of 2009, 152 countries
have signed the
Stockholm Convention on
POPs agreeing to reduce
the use of the top 12.
The
average American
household uses about 18
pounds of hazardous waste
each year.
Natural
Disasters can affect
the Earth’s surface, human
lives and property.
Earthquakes:
earth shakes due
to tectonic plates scraping
against one another
Landslide: rock
and soil
slide down a slope usually
after an earthquake
Tsunami: a
large ocean
wave caused by an
earthquake at the bottom of
the ocean
Volcano:
opening in the
Earth’s crust through which
lava, ash and gases are
ejected
Tornadoes:
type of
windstorm in which a
funnel of air drops down
from a storm cloud touches
the Earth
Hurricanes:
a powerful
storm that forms over the
ocean in the tropics
Avalanche:
mass of snow
sliding down a slope