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Rapporteurs' Reports
Much of the success of the colloquium must be credited to
WSTB members Lester Lave, James Mercer, Richard Conway, and
Gordon Robeck, who acted as rapporteurs for the workshops on
risk assessment/toxicology, hydrogeology, engineering, and regu-
latory strategies, respectively. The colloquium steering committee
provided them with the following list of questions for use in gen-
erating discussion, with an emphasis on technical and scientific
issues, during the workshop session.
. What methods are available for setting goals or standards?
How are they helpful?
. What are some strengths and concerns related to these
methods from a scientific, technical, or regulatory perspective?
. What is the ability of existing methods to account for
diverse conditions?
What is the adequacy of the data base in applying the
existing methods?
.
What uncertainties are associated with the methods and
their predictions?
.
What are the most important issues the methods neglect?
The following summaries of the workshops' efforts present the
wide diversity of opinion, vast breadth of expertise, and singular
177
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HAZARDOUS WASTE SITE MANAGEMENT
approaches to the resolution of the issues of concern that charac-
terized the entire colloquium.
RISK ASSESSMENT/ TOXICOLOGY WORKSHOP
Rapporteur: Lester B. Zaire
The workshop participants decided to focus on risk assessment
techniques for health and, most particularly, for cancer. Tools
exist to examine other health end points, trauma, and ecological
damage, but the participants felt constrained to leave these to
another time and place.
TOOLS FOR SETTING AMBIENT EN~ON~NTAI
STANDARDS
Four general approaches have been used to set ambient env
ronmental standards.
.
'1-
1. Using political and other nonscientific approaches. These
approaches do not attempt to use scientific data or criteria; nor
do they attempt to specify risks or health outcomes. Rather, they
grow out of political compromise or the imposition of one powerful
group's goals.
2. Setting the standard at the background (or nondetectable
level) plus some increment. For example, the standard for benzene
in water could be nondetectability, or background or twice the
background level.
3. Basing the standard on control technology and costs. Ex-
amples include the various EPA air and water emissions stan-
dards such as Best Available Control Technology (BACT) and
New Source Performance Standards (NSPS).
4. Setting the standards by risk analysis to quantify the mag-
nitude of the hazards and then by setting risk goals.
The first three of these approaches involve the "implicit" bal-
ancing of costs and risks. For example, the engineers determining
the best-available technology consider the costs and control effi-
ciency of each technology and implicitly decide which technologies
are too costly for incremental control. As long as industry and
the public have confidence in those making the implicit trade-offs,
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RAPPORTEURS' REPORTS
179
this can be a good approach. If that confidence is lost, however,
the balancing must be done explicitly, which requires risk analysis
and goal setting.
Criteria for Evaluating the Approaches
The following criteria were deemed the most relevant in evalu-
ating each of these approaches to setting standards: (1) efficiency/
effectiveness, (2) equity, (3) administrative ease, (4) transparency,
(5) the qualitative and quantitative uncertainty of the approach,
and (6) a miscellaneous category consisting of defensibility, resid-
ual risk, and others. The first criterion refers to whether the goal
is being accomplished and if so, whether it is being accomplished
at the least cost. The second criterion refers to whether the var-
ious parties are being treated fairly. Note that sometunes equity
is defined by process (having one's "day in court") rather than
by outcome (those who benefit must pay). The third and fourth
criteria are somewhat similar. The third looks at whether the
solution can be implemented simply and at low cost. The fourth
asks whether the approach is so simple that the public and other
parties understand how it works and see it as addressing their con-
cerns. The fifth criterion focuses on the extent to which scientists
are confident that their answer is qualitatively correct, and then
on the range of plausible quantitative estimates. The last category
refers to the ability of Congress and administrators to defend the
resulting goals and the risk after the process has been lowered
sufficiently to be accepted.
The criteria are best illustrated by applying them to the vari-
ous approaches. The first, political or arbitrary standard setting,
is not efficient or effective; it may be equitable, although those
who are unhappy are likely to complain that they had no chance
to present their case. Standard setting is administratively sim-
ple, although implementation may be extremely difficult. The
approach is not transparent because the public and other parties
are simply asked to trust the person making the arbitrary decision.
There is likely to be great qualitative and quantitative uncertainty
associated with the standard. Because the basis of the decision
is unknown, it is not likely to be defensible. Also, the residual
risk might be too high. In particular, this approach is faced with
the efficiency-residual risk dilemma. It is likely to impose too
high a cost or leave too large a residual risk. The background
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HAZARDOUS WASTE SITE MANAGEMENT
plus an increment criterion scores well on administrative ease, eq-
uity, transparency, residual risk, defensibility, and uncertainty. Its
principal problem is efficiency-it simply costs too much in most
cases.
Technology-based standards depend on the quality of the de-
cisionmakers and the information they have. If the process is
performed extremely well, it is likely to be efficient and admin-
istratively simple, and have low residual risk and relatively low
uncertainty. It will not be equitable, however, and so those who
must bear the burden will view themselves as having been treated
arbitrarily. Also, this approach is not likely to be transparent;
thus the public can easily lose confidence.
In fact, by the 1980s the first three approaches no longer
enjoyed the confidence of the public and other parties. Environ-
mental controls were too expensive for arbitrary or other political
judgments. Although background seems a wonderful goal, it is
incompatible with an industrial or other high-consumption soci-
ety. Engineering judgments have become more complicated as a
greater array of alternatives has emerged and as the control tech-
nology has become more expensive. It is simply not feasible to
rely on undocumented expert judgment in a highly emotional area
with many different levels of control and cleanup available at very
different cost levels. Thus, risk assessment and goal setting have
emerged as the prime approach to standard setting by default
rather than through an attractive display of the strong properties
of this approach.
Setting Risk Goals
Estimating the risks of some hazard is only one step in a long
process. Another necessary step is defining the safety goals: how
safe is safe enough? Several approaches have been proposed for
setting safety goals. In the 1980 "benzene decision, the Supreme
Court mentioned significant and trivial (de minimis) risks, without
ever attempting to define either. A significant risk was one so high
that it was worthy of attention and presumably of control. A de
minimis risk was so small that it was not worthy of attention.
Beyond this, the court gave few clues as to how to define these
concepts, and there has been little success by the agencies in
implementing the notions. The Food and Drug Administration
has defined a risk of one cancer per million lifetimes to be de
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R-APPORTEURS' REPORTS
181
minimis. EPA has been somewhat less explicit in considering that
risks on the order of one cancer per million lifetimes or per hundred
thousand lifetimes are de minimis.
Some researchers have used the notion of comparative risks.
They examine situations that we routinely encounter and accept
in our activities to infer the safety goals. For example, in smoking
cigarettes, someone is implicitly accepting high risks of lung can-
cer and heart disease. In eating peanut butter, one is implicitly
accepting the risk of liver cancer from aflatoxin contaminating the
peanut butter.
Finally, some researchers have attempted to examine the
safety implications of decisions made by federal regulatory agen-
cies. The agencies had no explicit safety goals and instead agonized
over each decision individually. Despite the individual decisions, a
pattern seems to emerge that gives some general guidance. Nev-
ertheless, setting safety goals is one of the most difficult steps in
the process.
Strengths and Weaknesses of Risk Aseesement and Management
In focusing on risk assessment the greatest strength was seen
as its internal consistency and its ability to make comparisons
across chemicals and waste sites. Risk assessment is targeted to
health outcomes, the area of greatest public concern. Furthermore,
it gives quantitative estimates of the health risks. Finally, the
method is able to deal with multiple chemicals and to offer an
aggregate measure of risk for such chemicals "stews." In summary,
risk assessment offers an intellectually appearing approach to a
difficult problem.
Its basic weakness stems from the difficulty of implementing
this approach, the method for which is complicated and difficult
to understand. Thus, few people understand the basis for the esti-
mates or the objections raised by injured parties. There are rarely
adequate data to implement the method, particularly with regard
to individual exposures. Indeed, exposure data were identified as
the primary source of uncertainty in current estimates. The com-
plexity of the method means that it is difficult to communicate
results and uncertainty to the public and to decisionmakers, a ma-
jor weakness in a democratic society. The models currently in use
were developed on the basis of somewhat plausible assumptions
rather than on the basis of the underlying biology. In the last year
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HAZARDOUS WASTE SITE MANAGEMENT
or two, however, great progress has been made in understanding
the biology of carcinogenesis, and recent work in pharmacokinet-
ics has developed the foundation for much better risk assessment
models.
The group also discussed the extent to which the risk esti-
mates had been validated. There has been some validation, but
first, one must understand that all current risk assessment tech-
niques are attempts to derive reasonable upper bounds to the
risk level. They are somewhat analogous to "probable maximum
floods." Thus, validation does not consist of asking whether the
risk estimates are accurate indicators of what is found in epidemi-
ological investigations. Because the risk estimates are reasonable
upper bounds, one needs to ask whether the risk estimates have
been found to understate the risks observed in the world. There
have been a few cases in which this question could be answered,
such as the bladder cancers from saccharin consumption; these
cases find that the risk levels estimated by the models are upper
bounds to what is measured in the world.
The Strengths and Weaknesses of Setting Risk Goals
Setting risk or safety goals requires public education and de-
bate; as a result the strengths and weaknesses of the method are
opposite sides of the same coin. Educating the public about safety
issues and about tiny levels of risk is extremely difficult. Even
statisticians have difficulty making decisions concerning small
probabilities unless they do the calculations first. Yet because
the United States is a democracy, there is no alternative to edu-
cating the public sufficiently to select a system for managing toxic
waste hazards.
Equity also plays an important role in the debate because
the public is concerned not only with the overall safety level but
with how the risk is apportioned. If children are at high risk, for
example, the public is concerned. Risk analysis has the ability to
estimate risks to individual groups, and thus safety goals must be
examined in detail.
CONCLUSION
The process of risk management and goal setting helps to
focus the attention of analysts, scientists, decisionmakers, and the
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RAPPORTEURS' REPORTS
183
public on the issues of critical importance. Thus, in an emotional,
complicated world, these tools help to push aside the secondary
issues and ensure that the important ones are highlighted; as a
result the tools help to ensure progress.
Risk assessment is still in its infancy, however, and there are
large uncertainties, both qualitative and quantitative, associated
with the estimates. Although advances in biology promise more
certain estimates in the future, the primary reason for using risk
assessment in setting standards is that nonscientific approaches,
approaches that do not balance safety and costs, and approaches
that do the balancing implicitly rather than explicitly are not
accepted by the public and other interested parties.
EPA's effort to bring the public into setting standards for the
ARSARCO smelter in Tacoma, Washington, is an example of how
difficult it is to educate the public about risk assessment and to
discuss safety goals. Yet whatever the difficulties, it is unclear that
there is any alternative to using risk assessment and setting safety
goals.
HYDROGEOLOGY WORKSHOP
Rapporteur: James W. Mercer
After discussing the colloquium papers the workshop group
summarized the role of hydrogeologists in hazardous waste site
management. That role is to use some methodology to estimate
exposure from ground water contamination. Exposure calcula-
tions are subsequently used with effects data in estimating the
associated risk. Such exposures may be estimated on a generic ba-
sis and the results used in setting policy, or the exposure may be
estimated on a site-specific basis and the results used to implement
policy. With this understanding as a foundation, the workshop ad-
dressed six questions presented to all workshops. Discussions of
the questions are given below under the following headings: Meth-
ods Used in Exposure Estimation, Strengths and Weaknesses of
the Methods, Methods' Electiveness Under Diverse Conditions,
Associated Data Base, Associated Uncertainties, and Important
Issues.
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HAZARDOUS WASTE SITE MANAGEMENT
METHODS USED IN EXPOSURE ESTIMATION
Hydrogeologists use a variety of methods to estimate exposure
at hazardous waste sites. These methods help us to understand
existing conditions and to evaluate remedial actions. They include
direct measurement, ground water modeling, theoretical calcula-
tions, and expert opinion.
Direct measurement includes tools and techniques normally
associated with site characterization such as siting, drilling, and
installation of monitoring wells; sampling ground water; and chem-
ical analysis of those samples. Ground water modeling refers to
the use of numerical and/or analytical solutions to simulate flow
and transport in the subsurface. Theoretical calculations include
statistical analysis and other mathematical expressions that are
not considered part of ground water modeling. Finally, expert
opinion refers to best professional judgment.
STRENGTHS Al WEAKNESSES OF TEE METHODS
Direct measurement or monitoring has the advantage of di-
rectly observing concentration distributions. This method should
be included even if other methods are selected. The disadvantages
of this method are its costs and the problems associated with
proper monitoring overt siting, well construction (making sure that
a representative sample is obtained), and sample analysis. Also,
this approach provides only a snapshot of the situation and not a
prediction of the future.
Ground water modeling is a valuable too! that aids site con-
ceptualization and the relative evaluation of various remedial alter-
natives. Modeling ground water flow is generally performed with
confidence. Unfortunately, that confidence is greatly diminished
when models are applied to organic transport. Such processes as
sorption and degradation are not as well understood as flow, and
rate constants describing these processes are generally unavailable.
Thus, modeling organics has a great deal of uncertainty associated
with it.
Statistical techniques, such as time series analysis, may be
helpful in predicting trends. These tools, however, require signifi-
cant data and do not aid in improving our physical/chemical un-
derstanding of solute transport. Other theoretical calculations-
for example, geochem~cal relationships may indicate possible
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RAPPORTEURS' REPORTS
185
reactions or transformations, but they cannot provide the reac-
tion kinetics. Therefore, these methods also have uncertainty
associated with them.
Expert opinion is used throughout these methods. It is used
to help site wells and to form conceptual models for testing and
analyzing. It is also used to estimate ranges of values for certain
parameters. Expert opinion by itself, however, without the above
methods, is of limited value.
METHODS' EFFECTIVENESS UNDER DIVERSE CONDITIONS
All of the above methods, given the limitations discussed, work
for diverse conditions if there are sufficient data. The uncertainty
introduced by a lack of sufficient data must be addressed when us-
ing any of the methods. For example, in a ground water modeling
application, multiple simulations may be required in which both
sensitivity analysis on uncertain parameters and scenario analysis
on uncertain conditions are performed.
ASSOCIATED DATA BASE
As indicated throughout this discussion a major problem with
all methods is the data or rather, the lack of it. The data re-
quirements may be divided into two groups: site-specific and
chemical-specific data. Site-specific data include hydrologic units,
intrinsic permeability distribution, source terms, hydrodynamic
dispersion, and so forth. Chemical-specific data include solubility,
wettability, volatilization, biodegradability, and others.
Participants in the workshop generally concurred in the be-
lief that both kinds of data are lacking. The emphasis at haz-
ardous waste sites is on chemical monitoring, and important hy-
drologic data, such as intrinsic permeability, are often overlooked.
In addition, the time frames associated with remedial investiga-
tion/feasibility studies are generally less than 1 year. Thus, not
even one annual cycle of hydrologic data will be available when the
remedy is specified. Chemical-related data are also lacking, a cir-
cumstance that is particularly true for multiphase flow problems
and chemical transformations.
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HAZARDOUS WASTE SITE AL4NAGEMENT
ASSOCIATED UNCE1ITAINT~S
The uncertainties associated with the four methods noted ear-
leir have been discussed throughout this report. More uncertainty
is associated with transport than with ground water flow. The
sources of this uncertainty are complex processes, data limita-
tions, and site variability.
Because of these uncertainties, the prediction of future organic
fates and their transport is very difficult. Although exact predic-
tions cannot be made, our ability to predict is adequate enough to
make many engineering decisions concerning remediation.
I~O:RTANT ISSUES
The following important issues were identified by the workshop
participants:
1. The methods discussed in this report must be used by
qualified people. Misuse of the methods obviously negates any
value that might be assigned to them.
2. The communication of results is critical. This process
should include the dissemination of enough information to allow
the results to be reproduced, the assumptions and methods used to
obtain the results, and the limitations and uncertainties associated
with the results.
3. It is important that these methods be validated and that
performance measures associated with these methods be verifiable.
4. Public education is important. Ground water character-
ization and cleanup is a long-term process, with some cleanup
standards exceedingly difficult to achieve.
ENGINEERING WORKSHOP
Rapporteur: Richard A. Conway
The formal presentations at the colloquium emphasized the
aspects of toxicology, hydrogeology (transport/transformation),
regulatory strategy, economics, and public concerns in setting
cleanup levels at hazardous waste sites. The role of engineering
was elucidated in a following workshop.
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187
The first step was to define what was meant by "engineering.
Webster's defines engineering as "the science by which the proper-
ties of matter and the sources of energy in nature are made useful
to man in structures, machinery, and products." The operative
word here is useful. Also encompassed by "products" presumably
would be the categories of processes and operations.
Thus, engineering transforms the findings of scientists (e.g.,
hydrogeologists and toxicologists) into products useful to man. In
terms of water quality issues the workshop participants recognized
that engineers play a role in developing useful models of trans-
port and transformation; they agreed to limit their discussion to
mitigation processes and operations, however, because engineering
plays a unique role in setting water quality goals.
DISCUSSION OF POSS~IE CHANGES ~ To
ENGINEERING ROTE
With material from the formal presentations of the collo-
quium, a schematic of the process of setting cleanup goals was
synthesized (Figure A). In this figure the cleanup goals that
is, the site-specific levels of acceptable exposure or risk-are es-
tablished by comparing release concentrations with background
levels; exposure concentrations with accepted concentration stan-
dards for chemicals in the various media; and the risk level with
policy goals for acceptable risk. When discrepancies between any
two of these inevitably are found, various mitigation strategies
are applied until a level of risk is achieved at a cost; and degree of
reliability acceptable to society. As shown in Figure A, mitigation
strategies can be applied to prevent releases, to contain releases,
or to treat the contaminated medium at the exposure point (see
Table A for some alternative mitigation strategies). This is an
iterative process; that is, various strategies are tested until an
acceptable risk level is achieved.
The process described above can take up to 4 years and cost
several million dollars before remediation, a 2-year process itself, is
even started. The workshop further explored a concept suggested
by David Miller during the colloquium to the effect that the time
and cost could be reduced markedly by starting studies of remedi-
ation alternatives immediately after release characterization and
well before the full risk assessment is completed (Figure A).
Knowing what kind of remediation is feasible in terms of
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HAZARDOUS WASTE SITE MANAGEMENT
S i te Best ri 3 ti on
Release Characterization
- t Transport/
Transfonrtati on
Ana 1 yS; S
(Al 1 Media)
i -1
1
Level Of
l ra) Exposure ,_
Detelilli nati on
1\
~ \
1 \
1 \
1 \
\
l
1
I Standards of
Chemicals in
Va ri OUS bledi a
I (Exposure
I Criteria)
Background
Level S
1
~1 ~
Cost g
Effectiveness
Data Base on
A1 ternati ve
Mi ti gati on
Strategi es
( Engi neeri ng )
-1
1_' 1
( a ) Dashed 1 i nes i ndicate
PersDeCtiVes of some Site-Specific Acceptable
environmental groups Exposure or Risk Levels
and regul atory agencies
(b) t)ash-dot-line is proposed earlier
i nvol vement of eng i Deeri ng i n the
standar~d-setting process
Demographics h
Envi ronmental
Studi es
_
Dose
Response
Assessment
\ Consequence
\ ~etet~lli nati on
~ ( Ri Sl( .
Chdracteri zati on )
Proposed
Prel imi nary
Engi neeri ng
Studies of
Mi ti gati on
Al ternatives
!
1
(b)
i
i
i
!
Pol icy
Goals Of
~ AcceDtabl e
pi sk
FIGURE A The role of engineering in establishing cleanup goals as dis-
cerned from colloquium presentations.
reliability to achieve goals (uncertainty), time to reach goals, per-
manency of goal attainment, and cost would provide direction for
the risk assessment instead of its pursual in the abstract. The only
factor keeping society from insisting on near-zero risk is the cost
of attaining it. Hence, knowing something of the cost-effectiveness
of engineered alternatives early in the process should markedly
speed up the assessment and thus the final remediation. In addi-
tion, factors that are critical to design are identified early and can
be resolved during the hydrogeologic studies and not later as an
add-on study.
In a similar vein but from a different perspective, during the
colloquium, Toby Page pointed out that factors like useful (cost-
effective) engineering solutions should be more fully considered.
When one tries to make an objective decision in this arena based
on classic risk analysis (an inexact process with great uncertainty),
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RAPPORTEURS' REPORTS
TABLE A Some Alternative Mitigation Technologies
189
Activity
Technology
Excavation and offeite disposal
Containment
Treatment of wastes and plumes
near release point
Treatment of plumes at the
drinking water wellhead
Physical barriers (e.g., Blurry walls and
caps, leachate collection)
Incineration and other thermal treatment
Stabilization, solidification for leaching
control
Soil flushing with water treatment
Soil biologic treatment
Pumping, treating, and recharging of
ground water
In situ biologic treatment of soil and
ground water
Chemical treatment (chemical reactions)
Physical separation of contaminants for
treatment (e.g., volatilization)
Air stripping and activated-carbon
adsorption
Based in part on U.S. General Accounting Office, Hazardous Waste: EPA's
Consideration of Permanent Treatment Remedies, GAO/ACED 86-178BR.
Washington, D.C., July 1986.
paralysis (inaction) can result. Subjective decisions often are ap-
propriate in cases in which uncertainties are great. Knowing the
effectiveness and cost of solutions is a component that helps a
subjective decision. But as David J. Len pointed out the need for
action should not be overemphasized; we should follow a policy of
ready-aim-fire and not ready-fire-aim. (As Tom HelIman quipped,
we should also avoid a policy of ready-aim . . ., ready-aim . .
ready-aim . . ., ready-aim-fire.)
Another observation of participants in the engineering work-
shop was that remediation systems cannot be reliably designed
for very low standards because design relationships are not proven
down to those levels. Also, analytical methods with "practical
detection limits" that is, reasonable detection levels based on
available analytical technology, considering economic and techni-
cal feasibility at or below the proposed cleanup standards are
needed for proper evaluation. Those individuals involved in risk
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HAZARDOUS WASTE SITE MANAGEMENT
assessment should keep this in mind as they debate goals in the
Tow micrograms-per-liter range.
In addition, engineers have a responsibility to describe the use-
fuIness of their design solutions in terms of effectiveness, reliability
(uncertainty), the time it takes to accomplish them, permanency,
and cost, in descriptions that are understandable to the public.
Specific uncertainties with the flushing method of soil cleanup,
the extraction/treat/recharge method of plume mitigation with
its associated problem of hysteresis because of slow Resorption,
and the longevity of plastic covers were identified. Also, much
less experience exists for in situ subsurface remediation compared
to surface treatment; consequently, the former is less reliable at
this time. Designs should be favored that fad] in a safe way, that
is, there is little risk to the community, and corrective action can
easily be taken.
Finally, the public needs to be informed of constraints in
the utility of remedial technology. Engineers need to get across to
decisionmakers who are trusted by the public what can and cannot
be done at a cost acceptable to society. For example, a qualitative
term like exorbitant cost could be expressed quantitatively in
terms of very low reductions in risk for the additional cost (Figure
B). Public expectations need to be tempered by the ability to
pay which is what the public ultimately does, no matter from
which pocket the funds originally came.
Also incumbent on engineers is the need to continue to seek
more elective, lower cost solutions to this problem. Further-
more, additional arbitrary political barriers to the implementation
of innovative options should be removed; in this manner, more
field sites could serve as engineering "laboratories" and potential
demonstration projects when risk to the public is minimal.
CONCLUSIONS
Engineering solutions that are cost-effective should be dis-
cussed early in the process of setting water quality standards; that
is, in selecting a method for dealing with a particular hazardous
waste site, consideration should be given to achievable engineering
solutions.
. Requiring a particular site to be rehabilitated to back-
ground or parts per billion levels often is not achievable with
present-day engineering methods.
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RAPPORTEURS' REPORTS
Site
Risk
~ .
Larc
risk
reduction
per unit
cost
FIGURE B Cost-effectiveness.
191
Low (de minimus) risk
reduction per unit cost
Range for
close evaluation
Site Remediation Cost
. Designs should be pointed toward rugged concepts that
are of a safe/faiT perspective rather than a fragile design in which
failure can result in serious consequences.
~ Engineers should take a leading role in helping to inform
the public and in some cases regulatory staff of the reliable en-
gineering aspects of hazardous waste site management and water
quality issues.
. Engineers need to communicate with the public on the al-
ternative solutions to a particular site cleanup: the cost versus the
level of pollutant cleanup, the reliability and uncertainty involved,
and the permanence of the alternatives.
REGULATORY STRATEGIES WORKSHOP
Rapporteur: Gordon Robecl~
The methods used by some states and EPA to set water quality
goals or standards rely heavily on a risk assessment that involves
setting some numerical concentration limit at a water use point.
Reducing carcinogens to a risk of lo-6 would be one example.
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HAZARDOUS WASTE SITE MANAGEMENT
Several workshop participants contended that this method has
not worked very well for federal cleanup cases and claimed that
available money, the time to do the cleanup, and feasible tech-
nology were and still are the driving forces for action. These
people seemed to prefer a goal based on future land and water
use, in addition to one that gives more weight to anticipated ex-
posures. Such a policy would give the local citizens more control
over how much cleanup they wanted and how much money should
be spent on a specific site. A third faction proposed that the most
straightforward goal was simply to clean up the site to its original
state.
One of the weaknesses of trying to calculate risk is that many
toxicants singly or in combination-have not been evaluated for
their health effects; thus, the total exposure from air or water,
or to the skin, for present or future users of the land and water
is difficult to estimate. Consequently, many believe a negotiated
technical solution to pump and treat ground water to the level of
surface water resources is the most practical and the quickest way
to confine the ground contamination. Although this approach has
been conducted successfully at some locations with the help of pre-
dictive models and strategically placed wells for testing the move-
ment and quality of water, there is still much to be learned about
contaminant retardation and biotransformation in the anaerobic
zone. Incidentally, the federal health program is making an ef-
fort to determine the health effects of 100 chemicals that may be
involved in such contamination, with perhaps hundreds more to
be considered in the distant future. Some estimate these evaTu-
ations may cost as much as $1 million-$4 million per chemical,
and even when they are completed, many in the field doubt that
the information will change the choice of technology for remedial
action. Others realize that health effect determinations and risk
assessment analysis must go forward and that with time and ef-
fort a stronger basis and understanding will support the remedial
actions and promote public confidence.
To expedite the cleanup process, EPA has proposed cIassify-
ing waters in three categories and thus guiding the decisionmaker
as to where, when, and how much cleanup should be required at
any one site. Some workshop participants thought that the sys-
tem of permitting discharges, as allowed by the Clean Water Act,
would be a fairer and more practical way of protecting a large
aquifer from excessive contamination. One state representative
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RAPPORTEURS' REPORTS
193
maintained that the decision tree process was working in his state,
but he also admitted that, initially, there was a lack of knowI-
edgeable well drillers, consultants, and stab people to aggressively
handle all the major cases. This individual stated, however, that
there has been rapid improvement in technology and personnel so
he is encouraged about future cleanup and source control. Other
workshop participants were concerned about the lack of oversight
and reliable statistics to help measure the rate of progress in the
state or federal cleanup programs.
Many people fee! a great frustration with the congressional
mandate to clean up to background levels, and they believe that
in 5 more years there will be great disappointment with the slow
rate of such cleanups. They think much of the effort must be
made by technical people to educate Congress and the public in
general as to what can be done with the available funds; they also
think it is necessary to convey how impossible it is going to be
to achieve original or background levels at all major sites. In any
event the workshop participants anticipated the need to be open
and flexible because circumstances will undoubtedly cause other
changes in legislation and in the availability of cleanup funds.
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Representative terms from entire chapter:
ground water
