Introduction
• What is Meant by “Environment”?
• What Is the Burden of Disease Due to the
Physical Environment?
Introduction
• How Does Risk Assessment Address the
Impacts of the Physical Environment?
• What is a Public Health Assessment?
• What Is an Ecological Risk Assessment?
• What Is an Interaction Analysis Approach?
• What is a Systems Analysis Approach?
Scenarios
Environment, Health, and Safety
Joe grew up in an industrial district of town.
His family lived in an old apartment building
and he played in a playground near a major
intersection. By the age of 6 Joe was found
to have high lead levels in his blood and was
not doing well in school. His mother
wondered, where could the lead come from?
Scenarios
Environment, Health, and Safety
Jill is pregnant and loves fish, which she
has eaten almost daily for years as part of
her effort to stay healthy. She hears that
fish should not be eaten regularly during
pregnancy. Why, she wonders, should I
cut down on eating something as healthy
as fish?
Scenarios
Environment, Health, and Safety
Ralph and Sonya, a prosperous
professional couple, and their two children
live in an older suburban home. They feel
secure that their environment is safe. They
were surprised to find when they wanted to
put their house up for sale that it did not
pass the safety tests for radon. Where did
the radon come from, they wondered, and
what can be done about it?
Scenarios
Environment, Health, and Safety
Sandra worked for an international agency
that had successfully addressed the
danger of radiation due to the hole in the
ozone. She was shocked when she was
told that she had a life-threatening skin
cancer called a melanoma. What could
cause melanoma, she asked. Could years
of sun exposure have played a role?
Scenarios
Environment, Health, and Safety
Seat belts on, children buckled in, airbags
activated, you head out the driveway to
face the world. You didn’t see that truck
coming when it hit you from the side. The
ambulance responded within minutes and
took your family to the nearest ER. You all
made it through with only minor injuries.
You ask yourself, was it just luck or did the
system work?
Four-step Risk Assessment and
Simplified Example: Benzene
Components
Simplified example:
benzene
Hazard Identification
Benzene causes leukemia
What health effects are caused by
the pollutant?
Strong evidence from cohort
studies and supportive
animal data exist
Four-step Risk Assessment and
Simplified Example: Benzene
Components
Dose-response relationship
What are the health problems at
different exposures?
Simplified example:
benzene
Strong dose-response
relationship among
occupational workers with
level of 1 ppm over a
working lifetime. The
impact of exposure at 1 ppm
is indistinguishable from
unexposed with rapid
increase in rates of leukemia
above that level.
Four-step Risk Assessment and
Simplified Example: Benzene
Components
Exposure Assessment
Simplified example:
benzene
Industrial exposures above 1
ppm common in a range of
How much of the pollutant are
industries at the time the
people exposed to during a specific standard was set.
time period? How many people are
exposed?
Over 250,000 workers
exposed to benzene
Four-step Risk Assessment and
Simplified Example: Benzene
Components
Risk Characterization
What is the extra risk of health
problems in the exposed
population?
Simplified example:
benzene
14–17 excess cases of
leukemia per 1000 workers
exposed to 10 ppm
throughout working lifetime
Where does lead in our bodies come from
and what can be done about it?
How Lead
Enters
Our bodies
Inhalation
Where it comes from
Workers in many lead-exposure industries:
Including mining, smelting, metal repair,
or
foundry work
Demolition and renovation activities that
generate fumes and dust, including home
renovations and hobby activities
Addition of lead to gasoline
Once inhaled deep into lung may remain
for
long periods and be absorbed into blood
over
time
Ways to reduce
exposure
Occupational controls
Phase-out of lead in gasoline in
U.S. from 1976 to 1996
Where does lead in our bodies come from
and what can be done about it?
How
Lead
Enters
Our
bodies
Where it comes from
Ingestion
Children—normal ingestion of dirt and dust
by infants and young children with up to 5%
of children who ingest large quantities—a
condition called “pica.” Children absorb
greater percentage of ingested lead than
Adults
Children’s toys and objects that are placed in
the mouth are especially important sources
Soil near old high traffic areas often
contaminated from previous lead in gas
Glazed pottery often includes lead that can
leach into food
Ways to reduce
exposure
Removal of lead paint from older
homes—lead levels in paint in the
1950s and earlier were as much as
50% lead
Enforce elimination of lead paint
from children’s toys
Monitoring and control of lead
levels in soil in young children’s
play areas
Very high blood levels may require
“chelation”—treatment to reduce
lead levels in blood
Where does lead in our bodies come
from and what can be done about it?
How
Lead
Enters
Our
bodies
Water
Where it comes from
Pipes especially in older water supplies and
homes built before the mid-1980s often
contain lead
Lead used in pipes outside and within the
home can leach into water—especially warm
water—over time
Ways to reduce
exposure
Regulation of levels of lead in
public water supply
Run home water before use
especially after away for extended
period. Use cold water for cooking
Where does lead in our bodies come
from and what can be done about it?
How
lead
enters
our
bodies
In-utero
Where it comes from
Pregnant women absorb higher
percentage of ingested lead
compared to children and can cross
placenta
Mother’s previous lead exposure stored
in her bones can be resorbed into her
blood during pregnancy
Ways to reduce
exposure
Special effort to reduce
exposure by pregnant women
including special care with
home renovations during
pregnancy especially homes
built before 1970
The Scope of Environmental
Diseases and Injuries
Environmental Diseases & Injuries
Unaltered
‘Natural’
Environment
Altered
Environment
Built
Environment
U.S. Environmental Protection Agency. Risk Assessment Portal. Available at: http://www.epa.gov/risk/hazardous-identification.htm. Accessed December
14, 2008.