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ENVIRONMENTAL HEALTH RISK 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. from electrocution (risk level 10-6 per year)

should I replace the wiring in my old house?

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The Nature of Risk

7000 people die annually in U.S. from falls in their homes

but ... most are over age 65, so should the rest of us ignore this?

It's all about CHOICES

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Estimating Risk

Probabilities are fine until it happens to me

Some of the uncertainty is due to chance, 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

chloroform in water

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Comparing Risks

Human nature dictates that we tend to worry more about risks that are severe and abrupt, as opposed to something that has some "probability" of occurring down the road

Many say that we “can’t” compare unlike risks, but in fact, we do it all the time

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The Costs of Risk Reduction Location Risk Reduction Cost per

(geog.) means life saved

Indonesia Death Immunization $100 countries (infection)

U.S./ Cancer Pollution $1,000,000 other prevention

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Why do we need Risk Assessment? "Emerging" risks - e.g. hormonal

analogues 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 Risk Assessment

health risk = the likelihood that an adverse effect will occur to a person (or group 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 in making decisions

Only in extreme cases will risks estimates 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 of Risk Estimates:

for carcinogens, the increased probability of individuals' getting cancer from a particular exposure

for other toxicants, a comparison of expected exposure to an exposure that is assumed to be insignificant

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Environmental Health Risk Assessments use two types of Risk Estimates

Why? Because they are most often used in USEPA risk assessments

In general, effects on systems such as the reproductive or immune system are not scrutinized nearly as much as carcinogenic effects

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What DON’T risk assessments estimate? 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 with the effect

lost income potential, costs to society

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Uncertainties in Risk Assessments Dose Effect = relationship between the

amount of a chemical exposure and the nature and/or severity of the toxic effect

Data on toxic chemicals usually come from:– laboratory experiments on animals NOT

epidemiology studies of humans– moreover, many are inferences based on

bacterial and/or human cells

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Uncertainties in Risk Assessments Dr. Bruce Ames, (Ames salmonella

microsomal screening test developer), stated repeatedly that he never intended for his "tool" to be applied as it is today

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Uncertainties in Risk Assessments 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 statistically significant effects

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Uncertainties in Risk Assessments many species are

homogeneous (purposely, to limit variability in response)

By contrast, humans are diverse in their response to chemicals due to:

– genetic make up– age– habits– occupation– health status– diet, etc.

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Uncertainties in Risk Assessments

some argue that extrapolations from animals to humans are more reliable than 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 Risk Assessments

When no effect is seen in lab animals, is there negligible risk to humans exposed at such a level?

a 1% incidence of any disease would be impossible to detect in a study of 25 animals, but would represent more than 2 million cases if the entire U.S. population were exposed

HOW DO WE ANSWER THIS QUESTION???

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Uncertainties in Risk Assessments In risk assessment, it is often

assumed that: 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 safe dose

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Public Perception and Public Demands The "vicious circle": public perception ->

media reporting -> congressional action -> agency regulation in response to public demands

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Public Perception and Public Demands

Are we (in the U.S.) better off now than before the "skyrocketing" industrial use of chemicals?

Since 1940 - life expectancy has increased 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 has

increased eight-fold)– the increase in life expectancy (you have

to die of something...)

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Where has this all brought us? Many times, the science of

epidemiology simply confirms the obvious - rarely has an epidemiological study drawn attention to an agent that was not already recognized by an astute observer in the field (e.g. Fen-Phen)

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Where has this all brought us? We fear carcinogens in our drinking

water ... but what about Milwaukee's public water supply and an outbreak of cryptosporidium? Would we better off taking some of our money from the former and spending it on the latter?

Asbestos: we won't even get into it ...

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Regulatory “Reform”

What agencies conduct health risk assessments?

OSHA EPA FDA USDA

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Regulatory “Reform”

1983 - the NAS published the "Red Book" - "Risk Assessment in the Federal Government: Managing the Process"

defined four steps of risk assessment, but more importantly, discussed how to separate the "science" from the "policy"

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Regulatory “Reform” 1987: EPA published "Unfinished

Business" - ranked items such as pesticides in food and radon as higher health risks than items such as groundwater contaminants or hazardous waste sites BUT...failed to rank airborne lead as a high risk - again, it was driven by carcinogens....essentially we have no scientific methods for comparing cancer with non-cancer risks

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Regulatory “Reform” 1991 - Federal Focus, Inc. called for an

executive order (16 CRR 171), essentially prohibiting the use of overly conservative assumptions

Risk Assessment has been represented by many as a "value free" process, when in fact it is full of judgements

Risk Assessment and Risk Management are, and should remain, separate processes

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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 risk assessment as means of telling us what the "real" risks are, so we can spend our money accordingly - represents another easy answer for attacking what ails us - after all, what politician in their right mind would outright oppose legislation that is supposedly "good for the environment"?

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Regulatory “Reform” State Trends: decreasing funding for public

health/environmental health programs but increasing environmental regulatory 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 "Contract with America" a bill called the "Job Creation and Wage Enhancement Act" bolstered risk assessment and cost benefit analyses requirements

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Cost-Benefit Analysis

A good example of cost-benefit analysis and the fallacies that can be put forth:

OSHA's proposed IAQ rule estimated that a facility manager would spend an average of 15 minutes documenting each complaint

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"Advancements" in the Science of Environmental Health Risk Assessment ASTM RBCA - Risk Based Closure

Assessment methodology many states have jumped on the

bandwagon for this approach to screening UST sites, especially as state funds have become more scarce

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ASTM RBCA - Risk Based Closure Assessment methodology

uses a tiered approach Tier I: "lookup tables" Tiers 2 - 4: incorporate more site specific values for:

– ground water– soil types– specific information on receptors

Still, much of the conclusions depend on mathematically modeled results - "garbage in - garbage out" still applies

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Conclusion: Where do we go from here?

Most environmental problems are extremely complicated technically

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Conclusion: Where do we go from here? We live in the age of entitlement: we

want the government to provide us a risk-free society, and we want it now!

We MUST decide how much minuscule reductions in risk we are willing to pay for

We MUST question our legislators AND regulators motives and actions

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Conclusion: Where do we go from here? We live in the age of technology, and

science can solve all of our ills: modern science has it's limitations, particularly when it comes to the analysis of living systems - it may never suffice in accurately 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 go from here? We live in the age of the sound

byte: most of the public gets the lion's share of this information from the media

We MUST improve communication of these issues dramatically

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Conclusion: Where do we go from 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 the children of men as a whole experience it. Avoidance of danger is no safer in the long run than outright exposure. Life is either a daring adventure, or nothing."... Helen Keller

“DON'T WORRY - BE HAPPY” ... Bobby McFerrin