CHAPTER 3

TRAGIC CHOICES

- Despite our seemingly frequent attempts to build a no-risk-society, there is no such thing

- Scientific progress has both:(a) created technical hazards(b) uncovered these hazards

Conversely, perceptions of risk and culturally dictated response to risk, are ancient parts of the human psych… flood/drought/etc. as “blessing”

or ”punishment” from the Gods… predicting / “controlling” physical or human environments… “survivability” of nuclear war

- The challenge is to accept that risks and hazards are a part of our daily lives

- The decision making processes related to risks and hazards is often little more than a “balancing act” of goals and responsibilities

How much is a life worth?

In order to carry out the larger discussion of risk/hazard/etc., basic information on the risk/hazard (so far as it is understood) is necessary… what are benefits/positive attributes as well as risks… what are spatial and temporal attributes of benefits/risks… what are political/economic/social costs

Information categories necessary for making risk decisions

1. Risk of an option must be articulated2. Benefits of an option must be stated3. Alternative options and associated

risks/benefits must be stated4. The level of certainty and uncertainty

associated with risks/benefits must be stated

5. How will these technical assessments be conveyed to decision makers

Analytical Tools: Cost-Benefit Analysis

- A long tradition as a chief tool of decision making--- involved comparing estimated short-term and long-term costs and benefits of alternatives

- Used properly, a reasonable guide for estimating future behavior

Analytical Tools: Cost-Benefit Analysis, cont

Some very controversial aspects:(1) What discount rate(s) should we

assign (2) Cannot be applied democratically(3) Assumes “full-cost information”(4) Pulling a price on environmental

goods is at best debatable(5) Rules out any possibility of

catastrophic events

Analytical Tools: Cost-Benefit Analysis, cont

A fundamental construct of C-B is that there exists anOptimal level of risk/hazard

Is there such a thing?

Policy makers have sought an alternative methodology

Risk-BenefitComparing risk with anticipated

benefits--- greater risk accepted in anticipation of greater benefit--- not always quantitatively driven

[“balance sheet” methodology]--- still not perfect – weighs a current

perspective to risk and benefit; issues of equality; etc

Revealed Preferences

Starr, Science magazine, 1969Based on the idea that study of

historical data on risk-benefit comparison will illustrate “patterns” of acceptability across a range of technologies

Revealed Preferences, cont

From study of cost-benefits Starr developed acceptability laws:

1. Risks are acceptable from a technology if they are proportional to the 3rd power of the benefit

2. The public will tolerate risks from voluntary activities (order of 1000x) over that of involuntary risks

3. Risk acceptability is inversely related to the population at risk

Revealed Preferences Limitations

Cutter provides two (I think viewing as three makes more sense):

1. Risk is defined as human fatalities… human health/welfare; environmental degradation; etc, are not addressed

2. Ignores delay between technology introduction and impact

3. Fails to examine equity

Expressed Preferences

Assessment of public views / attitudes on risk… most commonly through direct

opinion polling… timing of polling and nature of

risk directly affects public sentiment… realistically, very limited use

potential

Risk Assessment

Uses incidence data and modeling techniques to develop hypothesizes and conclusions about the level of harm from human activity

Risk Assessment, contFour “stages” to risk assessment:Stage 1. Risk Assessment

identification or determination of an activity/chemical link to health effect- Looking at chemicals, there are a myriad of possible impacting chemicals

A Legal Question

Exposure to a pesticide in year Y gives rise to 10 additional cases of cancer in a population of 100,000 in the year Y+20…

Who should be allowed to sue for damages, and for how much?

Risk Assessment, cont

Chemicals, cont- acids- hematoxins- neurotoxins - carcinogens - mutagens- teratogens

Risk Assessment, contChemicals, cont

- additionally, research indicates that long-term exposure to

certain compounds will effect:(1) endocrine system(2) immune system(3) nervous system- hormonal copycats

InterestingThe Delaney Amendments to the Food,

Drug and Cosmetics Act, forbidding the sale of any food additive containing a carcinogen in however small a quantity, had to be partially repealed when science advanced to the point of detecting such minute levels of carcinogens that clearly harmless substances were being outlawed

Risk Assessment, contStage 2. Examination of the

relationship between magnitude of exposure and the probability of occurrence of adverse health effects as identified in Stage 1… this is toxicology… we are seeking to quantify

dose-response

Risk Assessment, contDose-response, cont- Whether or not a substance is

dangerous is a result of:(1) Size of dose over a period of time(2) frequency of exposure(3) who is exposed(4) how well the body’s detoxification

system is operating

Risk Assessment, contInteresting:

Legally a poison is a chemical of LD50 – a lethal dose of 50 milligrams or less per kilogram of body weight

[LD50 is the amount of a chemical received in one dose that kills 50% of animals in a test population within a 14 day period]

Risk Assessment, contStage 3. Calculation of range and extent

of exposure- examined include:

(1) source and amounts of exposure

(2) amounts absorbed, distributed and stored in the body

(3) amount excreted(4) effects on different parts of

the body

Risk Assessment, cont

Researchers distinguish between: acute exposure chronic exposuresub-chronic exposure

Risk Assessment, cont

Stage 4. Risk characterization –description of the nature and magnitude of human risk as well as some statement of uncertainty for the estimate

* As a methodology, risk assessment has its own areas of disagreement *

Risks to Human Health- Usually based on involuntary

exposure - Most common ways of

examining this risk:(1) disease clusters – based on

identification of abnormal patterns of disease

Most Common Ways of Examining Risk, cont

Clusters, cont- considered least valuable identification methodology- least scientific- rarely conclusive- is observed a true aberration?

Most Common Ways of Examining Risk, cont

Clusters, cont- valuable as an indicator of the need for more intensive

examination- relatively inexpensive

Most Common Ways of Examining Risk, cont

(2) Epidemiological data – studies of populations of humans exposed to compounds - general sense a study of toxicity and hazard by answering the question of why some in a population are susceptible to a hazard

Most Common Ways of Examining Risk, cont

Epidemiological, cont- a field study methodology attempting to show a correlation between environmental contamination and human disease- a statistical study of an exposed

population vs a control population

Most Common Ways of Examining Risk, cont

Epidemiological, cont- conclusive evidence difficult to attain:

(a) multiple chemical sensitivity (MCS)

(b) delay between exposure and on-set

Most Common Ways of Examining Risk, cont

(3) Animal bioassay data(laboratory investigations)- usually on test animals- chronicles body parts affected

and process of the harming action - basis for toxicological studies

--- premise that animal studies can be extrapolated to humans

Most Common Ways of Examining Risk, cont

Animal bioassay data, cont- question of extrapolation- question of validity of extrapolating large dose animal

studies to smaller-dose long term exposure to humans

- most common investigative methodology for acute toxicity

Most Common Ways of Examining Risk, cont

Animal bioassay data, cont- lab experimentation seeks to

establish dose-response curves

--- controlled experiments--- cohort group

experiments

Most Common Ways of Examining Risk, cont

Animal bioassay data, cont- “Fairly high” doses are tested

to:(1) reduce lab animals needed(2) shorten time needed to document a response(3) lower cost

Most Common Ways of Examining Risk, cont

Animal bioassay data, cont- Problems lab experimentation:

(1) extrapolation validity – doselinear dose-response modelthreshold dose-response

model(2) extrapolation validity – species(3) long and expensive process

Most Common Ways of Examining Risk, cont

(4) Experimental studies of mutagenicor carcinogenic property- comparison of molecular structure to isolate chemical

structures that might identify carcinogens

- based on premise that known carcinogens might share a common chemical structure

Interesting

Animal bioassayChance rat will No. of sodas/daydevelop tumor human must drink

for same dose1 in 50,000 11 in 5000 101 in 500 1001 in 50 10001 in 5 10000

Environmental Risks

- Result from a number of sources: technological systems failure; environmental processes; human behavior patterns

- complex because both human risk and environmental impacts are taken into account

Environmental Risk Techniques

Fall into three broad categories (see Table 2-2):(1) monitoring and surveillance(2) modeling(3) screening and testing for

exposure/response

Environmental Surveillance

The (1) above- Observation of spatial and temporal

patterns of environmental indicators and their variations

- Source of baseline data for comparative trends and geographic analysis

- Source of data for annual international reporting

Interesting Applied Example

Sept 1998 Ft. Campbell RAB were told of two methodologies under study for modeling contaminant flow through karst(1) Present-Future(2) Mass-Transport

CausalityStage 2 above- Delineation of chain of events,

pathways and processes connecting cause (or source) of a problem to its effects--- environmental modeling is often used

… forms: schematic; mathematical; interactive computer

Simple illustration of this causality

As the average grade of ore declines from 8% or more to 3%, there is a barely perceptible increase in the amount of mine waste generated per ton of final metal. Below 3% wastes per ton increase dramatically. Eventually the cost of dealing with the wastes will exceed the value of the metal produced.

Exposure Response

Stage 3 above- Seeks to determine the relative characteristics of the impact of exposure (dose) to the type of environmental impact (effect)- As seen before, illustrated by use of graph curves and useful for prediction of effects of very high or very low exposure

Exposure Response, cont

Text tells us that two main types of dose-response relationships are worth noting (p 43):(1) threshold relationships(2) zero threshold

Who’s Right: The Experts or the Public?

Expert vs Public Views(1) social changes(2) increasing reliance on technology(3) the public’s increasing distrust of institutions(4) the institutionalization of

scientific conflict