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EH&S, Inc. 1
ENVIRONMENTAL HEALTHRISK ASSESSMENTS
SCIENCE OR VOODOO?
Ron Pearson, M.S., CIHEnvironmental Health & Safety, Inc.
St. Paul MN
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The Nature of Risk
200 people die annually in U.S. fromelectrocution (risk level 10-6 per year)
should I replace the wiring in my oldhouse?
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The Nature of Risk
7000 people die annually in U.S. fromfalls in their homes
but ... most are over age 65, so shouldthe rest of us ignore this?
It's all about CHOICES
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Estimating Risk
Probabilities are fine until it happens tome
Some of the uncertainty is due tochance, some of it isn't
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Estimating Risk
Historical risks are easily understood -e.g. car accidents
What kind of car do you drive? Does it have airbags?
Do you drive fast?
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Comparing Risks
action annual risk uncertainty
all cancers 3 in 1,000 10%
pack-a-day 4 in 1,000 150%smoker
mountain 6 in 10,000 50%climber
car accident 24 in 10,000 10% drinking MCL 6 in 1,000,000 1,000%
of chloroformin water
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Comparing Risks
Human nature dictates that we tend toworry more about risks that are severeand abrupt, as opposed to somethingthat has some "probability" of occurringdown the road
Many say that we cant compareunlike risks, but in fact, we do it all thetime
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The Costs of Risk Reduction
Location Risk Reduction Cost per(geog.) means life saved
Indonesia Death Immunization $100countries (infection)
U.S./ Cancer Pollution $1,000,000
other prevention
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Why do we need Risk
Assessment? "Emerging" risks - e.g. hormonalanalogues
Shifts in perception information overload - the "health studies"results that we are bombarded with daily
ability to measure minute amounts of
substances
many traditionally severe health risks(e.g. smallpox) are gone
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Environmental Health RiskAssessment health risk = the likelihood that an
adverse effect will occur to a person (orgroup of persons) in a chemical
exposure situation Usually, a higher exposure causes more
serious effects or makes them more
likely At some low exposure level, the risks
become insignificant
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Estimates of Risk
Estimates of risk are needed to assist inmaking decisions
Only in extreme cases will risksestimates alone drive decision making
zero risk compels no action, while a
great risk may compel immediate action IN REALITY, risk estimates lie
somewhere in between
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Environmental Health Risk
Assessments use two types ofRisk Estimates:
for carcinogens, the increased
probability of individuals' gettingcancer from a particular exposure
for other toxicants, a comparison of
expected exposure to an exposure thatis assumed to be insignificant
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Environmental Health Risk
Assessments use two types ofRisk Estimates
Why? Because they are most often usedin USEPA risk assessments
In general, effects on systems such asthe reproductive or immune system arenot scrutinized nearly as much ascarcinogenic effects
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What DONT risk assessmentsestimate? total number of people affected relative incidence of an adverse effect in
populations known to be exposed with
those not exposed the ratio of the expected risk with the
exposure to that expected without it
reduced life expectancy associated withthe effect
lost income potential, costs to society
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Uncertainties in RiskAssessments Dose Effect = relationship between the
amount of a chemical exposure and thenature and/or severity of the toxic
effect Data on toxic chemicals usually come
from:
laboratory experiments on animals NOTepidemiology studies of humans
moreover, many are inferences based onbacterial and/or human cells
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Uncertainties in Risk
Assessments Dr. Bruce Ames, (Ames salmonellamicrosomal screening test developer),stated repeatedly that he neverintended for his "tool" to be applied as itis today
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Uncertainties in RiskAssessments both of these sources of data cause
problems because:
an animal or cell is not a human being
most animal toxicity data is short-term
relatively high exposures are used
experimentally, to cause statisticallysignificant effects
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Uncertainties in Risk
Assessments many species arehomogeneous(purposely, to limit
variability inresponse)
By contrast, humansare diverse in theirresponse tochemicals due to:
genetic make up
age
habits
occupation
health status
diet, etc.
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Uncertainties in RiskAssessments
some argue that extrapolations fromanimals to humans are more reliablethan epidemiology studies, due to:
small study populations (lack of"statistical significance")
confounding variables
lack of exposure data differences between study populations
and the population to be protected
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Uncertainties in RiskAssessments When no effect is seen in lab animals, is
there negligible risk to humans exposedat such a level?
a 1% incidence of any disease would beimpossible to detect in a study of 25animals, but would represent more than
2 million cases if the entire U.S.population were exposed
HOW DO WE ANSWER THISQUESTION???
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Uncertainties in Risk
Assessments In risk assessment, it is often assumedthat:
for cancer: there is no safe dose, and; at low doses, the relationship between
dose-effect is directly proportional(linear)
for other health effects: there is a safedose
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Public Perception and Public
Demands The "vicious circle": public perception ->
media reporting ->congressional action ->agency regulation in response to publicdemands
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Public Perception and PublicDemands
Are we (in the U.S.) better off now thanbefore the "skyrocketing" industrial useof chemicals?
Since 1940 - life expectancy hasincreased nearly 15 years
Since 1970 - infant mortality has
decreased by 1/2 Since 1970 - heart disease has dropped
by nearly 1/3
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Public Perception and Public
Demands Cancer deaths have increased...or have
they?
Many feel the this is due simply to: smoking (increases lung, pharyngeal,
pancreatic and bladder cancer incidence)
sun exposure (malignant melanoma hasincreased eight-fold)
the increase in life expectancy (you have todie of something...)
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Where has this all brought us?
Many times, the science ofepidemiology simply confirms theobvious - rarely has an epidemiologicalstudy drawn attention to an agent thatwas not already recognized by an astuteobserver in the field (e.g. Fen-Phen)
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Where has this all brought us?
We fear carcinogens in our drinkingwater ... but what about Milwaukee'spublic water supply and an outbreak ofcryptosporidium? Would we better offtaking some of our money from theformer and spending it on the latter?
Asbestos: we won't even get into it ...
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Regulatory Reform
What agencies conduct health riskassessments?
OSHA EPA
FDA
USDA
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Regulatory Reform
1983 - the NAS published the "RedBook" - "Risk Assessment in the FederalGovernment: Managing the Process"
defined four steps of risk assessment,but more importantly, discussed how toseparate the "science" from the "policy"
R l R f
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Regulatory Reform
1987: EPA published "Unfinished
Business" - ranked items such aspesticides in food and radon as higherhealth risks than items such as
groundwater contaminants orhazardous waste sites BUT...failed torank airborne lead as a high risk - again,it was driven bycarcinogens....essentially we have noscientific methods for comparing cancerwith non-cancer risks
R l R f
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Regulatory Reform
1991 - Federal Focus, Inc. called for an
executive order (16 CRR 171),essentially prohibiting the use of overlyconservative assumptions
Risk Assessment has been representedby many as a "value free" process, whenin fact it is full of judgements
Risk Assessment and Risk Managementare, and should remain, separateprocesses
R l R f
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Regulatory Reform Risk Assessment produces very precise
numbers of questionable accuracy
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Regulatory Reform
Federal Trend: legislators pursuing riskassessment as means of telling us whatthe "real" risks are, so we can spend ourmoney accordingly - represents anothereasy answer for attacking what ails us -after all, what politician in their right
mind would outright oppose legislationthat is supposedly "good for theenvironment"?
R l t R f
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Regulatory Reform State Trends: decreasing funding for
public health/environmental healthprograms but increasing environmentalregulatory spending - in 1994 we spent$4.09 per capita on the former and$18.87 per capita on the latter
In the Republican party's "Contractwith America" a bill called the "JobCreation and Wage Enhancement Act"bolstered risk assessment and costbenefit analyses requirements
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Cost-Benefit Analysis
A good example of cost-benefit analysisand the fallacies that can be put forth:
OSHA's proposed IAQ rule estimatedthat a facility manager would spend anaverage of 15 minutes documenting
each complaint
"Ad t " i th S i
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"Advancements" in the Scienceof Environmental Health Risk
Assessment ASTM RBCA - Risk Based Closure
Assessment methodology many states have jumped on the
bandwagon for this approach toscreening UST sites, especially as statefunds have become more scarce
ASTM RBCA Risk Based Closure
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ASTM RBCA - Risk Based ClosureAssessment methodology
uses a tiered approach
Tier I: "lookup tables"
Tiers 2 - 4: incorporate more site specificvalues for: ground water
soil types
specific information on receptors
Still, much of the conclusions dependon mathematically modeled results -"garbage in - garbage out" still applies
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Conclusion: Where do we gofrom here?
Most environmental problems areextremely complicated technically
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Conclusion: Where do we gofrom here? We live in the age of entitlement: we
want the government to provide us arisk-free society, and we want it now!
We MUST decide how much minusculereductions in risk we are willing to payfor
We MUST question our legislatorsAND regulators motives and actions
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Conclusion: Where do we gofrom here? We live in the age of technology, and
science can solve all of our ills: modernscience has it's limitations, particularlywhen it comes to the analysis of livingsystems - it may never suffice inaccurately predicting health effects or
their potential from low level exposures We MUST decide how much
uncertainty we are willing to tolerate
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Conclusion: Where do we gofrom here? We live in the age of the sound byte:
most of the public gets the lion's shareof this information from the media
We MUST improve communication ofthese issues dramatically
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Conclusion: Where do we gofrom here?
We live in the age of cancer paranoia:most of the EPA's regulatory efforts
focus on cancer We MUST shift the emphasis equally to
non-cancer endpoints
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"Security is mostly a superstition. It
does not exist in nature, nor do thechildren of men as a whole experienceit. Avoidance of danger is no safer inthe long run than outright exposure.Life is either a daring adventure, ornothing."... Helen Keller
DON'T WORRY - BE HAPPY ...Bobby McFerrin