This paper is available online with live links at: http://www.rachel.org/library/getfile.cfm?ID=363
Precautionary guidance for toxic site cleanups
DRAFT 5, April 13, 2004
Peter Montague 732-828-9995; peter@rachel.org; www.rachel.org
Overview of this presentation:
I. Why is a precautionary approach needed?
a. The non-precautionary approach has led to considerable harm, world-wide.
b. The world is now full -- of humans and their artifacts -- so the human economy is now large
enough to threaten the integrity of the ecosystems that humans depend upon. This is a recent
development and we are just beginning to learn to adjust to this new reality. New conditions call for
new approaches.
c. The public trust responsibility of government calls for a precautionary approach.
II. What is the Precautionary Principle?
III. Applying the precautionary principle to a toxic site.
I. WHY IS PRECAUTION NEEDED? -- Part a
I.a. Failures of the Risk-Based (Non-precautionary) Approach
The current "risk-based" regulatory system rests on three assumptions:
1) Assumption No. 1: humans can manage the biosphere by deciding how much harm the
Earth (or any portion of the Earth) can safely absorb. This is sometimes known as the
"assimilative capacity" approach. According to this approach, scientists can reliably determine how
much harm the Earth, or any portion of the Earth (such as the Hudson River, or bald eagles, or a
human population), can absorb or assimilate.
2) Assumption No. 2: Once the "assimilative capacity" for a particular chemical (or other
kind of harm) has been determined, then we can -- and will -- see to it that no greater amount
of damage is permitted. We will enforce limits, river by river, factory by factory, chemical by
chemical so that the total, cumulative releases to not exceed the "assimilative capacity" of the Earth
(or any portion of the Earth).
3) Assumption No. 3: We already know which substances and activities are harmful and
which are not; or, in the case of substances or activities that we never suspected are harmful,
we will be warned of their possible dangers by traumatic but sub-lethal shocks that alert us to
the danger before it is too late.[1]
Obviously the system really hinges on Assumption No. 1 -- that we can determine the "assimilative
capacity" of an ecosystem, or of a population of birds or polar bears or humans. For this purpose, a
special technique has been developed called "risk assessment."
In the U.S., risk assessment is now a fundamentally important decision-making tool. Risk
assessment now provides the basis for almost all environmental management, not merely the
control of chemicals. Before cutting new roads into a national forest, someone completes a risk
assessment to decide how much the roads will harm bears and other forest dwellers. Ocean fisheries
are managed by risk assessment to determine the "maximum sustainable yield" of fish.[2] Risk
assessment determines allowable drug residues in beef, allowable pesticide residues in food,
allowable withdrawals of water from rivers and aquifers, allowable contamination of drinking
water, limits on the discharge of fine particles and toxic chemicals from coal-fired power plants,
auto emission limits, livestock grazing allotments on arid lands, allowable harvests of endangered
species, fishing and hunting quotas, workplace exposure limits, radiation limits in medical settings,
cleanup standards for contaminated sites, and on and on.[3]
Four Difficulties of Risk Assessments (Among Others)
1. The Risks of Multiple Hazards (e.g., Chemical Mixtures) Cannot Yet Be Assessed
Most people are routinely exposed to mixtures of chemicals (pharmaceuticals, food additives,
pesticide residues, second-hand tobacco smoke, vehicle exhausts, disinfectants and cleaning agents,
fine and ultrafine particles from combustion sources, pollutants in drinking water, and exudates
from consumer products, among others) along with other stresses (ultraviolet radiation, bacteria and
viruses, genetic disorders, aging, etc.). Such combinations of complex chemical exposures and
stresses are rarely acknowledged, and their combined effects on health and behavior cannot be
assessed with any substantial degree of confidence.[4]
2. Low-Level and High-Level Exposures Can Produce Different Effects but Low-Level
Exposures Are Rarely Examined
Low-level exposure to a particular chemical can sometimes produce effects quite different from
those caused by higher doses of the same chemical. These differences can include positive effects
at low doses (hormesis) and harmful effects at higher doses -- as in the case of the essential
mineral, chromium. Or, in the case of some chemicals that interfere with biochemical signaling
systems, harm can occur at low doses but not at higher doses, exhibiting an inverted-U shaped
dose-response curve.[5]
Testing of low doses of chemicals has typically been avoided because large numbers of animals are
required so costs can be prohibitive.
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3. Some Chemicals Are Only Active During a Brief Stage of Development
Some chemicals are only biologically active during a brief period of time (a "window of
vulnerability") in the development of an organism, so toxicity must be tested during those particular
times. Chemicals tested during other times will appear to be less potent or even inert.[6]
4. Basic data are often lacking, so judgments and assumptions must be relied upon
The National Academy of Sciences has said, "Risk assessment techniques are highly speculative,
and almost all rely on multiple assumptions of fact -- some of which are entirely untestable."[7]
As a result, despite many advances in the science of toxicology during recent decades, conclusions
about risk can still vary dramatically depending upon who is doing the risk assessment.
As William Ruckelshaus (first administrator of U.S. Environmental Protection Agency) said in
1984, "We should remember that risk assessment data can be like the captured spy: If you
torture it long enough, it will tell you anything you want to know."[8]
Peer review of risk assessments by all stakeholders can reduce the range of disagreement;
nevertheless, despite substantial effort and constant improvements in risk assessments, the goal of a
rational and reproducible technique for making decisions has eluded decision-makers.
There are many excellent case studies of instances in which the risk-based approach has left us a
legacy of very expensive problems that we are now struggling to solve, including: depleted
fisheries; harm from x-rays and radioactivity; exposures to benzene, asbestos, and PCBs; damage to
the Earth's ozone shield; exposure to the artificial hormone, diethylstilbestrol (DES); the excessive
use of antimicrobials and growth promoters; lead in gasoline, and MTBE as a substitute for lead in
gasoline; tributyl tin as an anti-fouling paint on ships and boats; chemical contamination of the
Great Lakes; and more.[9]
I. WHY IS PRECAUTION NEEDED? –Part b
I.b. The world is now full -- of humans and their artifacts
** The human economy uses, directly or indirectly, roughly 40% of the net primary product
of terrestrial photosynthesis.
This means that, with one more doubling of human population (40 to 45 years), humans will be
appropriating 80% of net terrestrial primary productivity.[10]
** One result of human appropriation of the earth's terrestrial resources is soil degradation,
which is widespread; worldwide, rates of soil loss exceed rates of soil formation by at least a
factor of 10.[11]
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** Another result of human appropriation of terrestrial resources is the rapid loss of species,
which is now proceeding at a rate somewhere between 100 and 1,000 times the historical rate
of extinction.[12]
** The human contribution to atmospheric carbon dioxide (a 30% global increase in 200
years) and methane (which doubled in concentration during the same period) indicates that
the human economy is now capable of disrupting ecosystems at a global scale.
** The buildup of greenhouse gases in the atmosphere, and the rupture of the earth's
stratospheric ozone shield by chlorofluorocarbons (CFCs), indicate that the human economy
has already exceeded the assimilative and regenerative capacities of the biosphere to absorb
some human wastes.
There is considerable evidence to support this general proposition. For example, persistent
synthetic toxicants are now measurable from the peaks of the highest mountains to the floors of the
deepest oceans and everywhere in between.
It seems evident that nature is unable to degrade certain synthetic compounds as rapidly as humans
are able to produce them.
Science is changing as a result of the "full world hypothesis." For example, two new academic
fields emerged in the mid-1980s -- conservation biology, and ecological economics.[13]
Ecological economists argue the "full world" hypothesis will require humans to re-organize their
intellectual activities, shifting the fundamental scientific paradigm from Newtonian physics to
ecology.
Newtonian physics views the world as linear, separable, reducible to its component subsystems that
can be readily aggregated to model the behavior of the whole system.
In contrast, an ecosystem perspective develops a worldview adapted to complex living systems -constantly interacting and evolving, nonlinear, and not scalable by simple aggregation.
In the ecological view, human knowledge of the evolving world is fraught with fundamental
uncertainties that are large and likely to remain so, spawning a scientific approach that has less
confidence in its predictions and prescriptions than was common in an earlier era.
The ecological approach has produced a generation of scientists who advocate greater humility and
a more precautionary approach than was common in the past, with an orientation toward learning
from nature for the purpose of working with it rather than subduing it.
Here we see that the precautionary approach is a response to scientific uncertainty. Environmental
scientists are now exploring ways in which their discipline(s) can be made more helpful to those
who want to act with precaution – without compromising the integrity and objectivity of
science.[14]
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I. WHY IS PRECAUTION NEEDED? – Part c
I.c. The Public Trust Doctrine
The Public Trust Doctrine is an ancient legal doctrine handed down to us from Roman law, through
English law, into the law of the 13 original colonies and now the states.[15]
The public trust doctrine asserts that the sovereign (in our case, state government) has an
inalienable duty (a duty that cannot be denied or given away) to protect the common wealth -- air,
water, wildlife, public health, our genetic heritage, and more -- which we all inherit and own
together and none of us owns individually.[15]
As trustee, government must protect the trust assets (nature and human health) for the trust
beneficiaries (present and future generations). Government even has a duty to protect the trust
assets against harmful actions by the beneficiaries themselves, and so from time to time
government must limit some of the prerogatives of private property in order to protect the common
wealth for present and future generations.
In carrying out its duty to protect the public trust, government has a duty to anticipate harm, to look
ahead to protect the trust against impending threats.[16] If government waits until harm can be
demonstrated beyond doubt, then it will be too late -- the trust property will be damaged and
government will have failed in its duty as trustee.
The precautionary principle provides a way for government to fulfill its responsibility to protect the
public trust, to anticipate and avoid harm, to foresee and forestall.
II. The Precautionary Principle
The precautionary principle provides the basis for a new way of making decisions about the
environment and human health. Instead of asking, "How much harm will we tolerate?" or "How
much harm can we get away with?" the precautionary approach asks, "How much harm can we
avoid?"
The precautionary principle originated in Germany in the 1970s in response to damage by acid rain
in the beloved Black Forest. The original German concept, "Vorsorgeprinzip," was developed to
guide environmental planning. It translates best as "the principle of forecaring" but it also carries
the connotation of foresight and preparation for the future, not merely precaution.
In one form or another, the language of precaution has now been adopted in many international
treaties and conventions, such as the North Sea Declaration (1987), The Ozone Layer Protocol
(1987), the Ministerial Declaration of the 2nd World Climate Conference (1990), the Maastricht
Treaty that created the European Union (1994), The United Nations Law of the Sea (2001), and the
Cartagena Protocol on Biosafety (2000), among others.
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The United States adopted the precautionary principle when it signed the Rio Declaration on
Environment and Development in 1992; principle 15 of that agreement says,
"In order to protect the environment, the precautionary approach shall be widely applied by States
[nations] according to their capabilities. Where there are threats of serious or irreversible damage,
lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures
to prevent environmental degradation."[17] Cost-effective means lowest-cost.
Unfortunately, the U.S. federal government has never acted upon this commitment and indeed is
sometimes openly hostile to a precautionary approach. (For example, see
http://www.house.gov/reform/min/inves_admin/admin_reach.htm )
Another formulation of the PP appeared in a consensus statement in 1998:
"When an activity raises threats of harm to human health or the environment, precautionary
measures should be taken even if some cause and effect relationships are not fully established
scientifically."[18]
All formulations of the precautionary principle contain three basic elements:
a) Where there is reasonable suspicion of harm occurring or about to occur...
b) and there is scientific uncertainty as to cause and effect...
c) then we all have a duty to take action to prevent harm.
Notice that the precautionary principle puts ethics first -- we all have a duty to prevent harm.
But also notice that the precautionary principle does not tell us what kind of action to take. It does
not tell us to ban or regulate. It simply tells us to prevent harm.
Some formulations of the precautionary principle suggest the kinds of actions we should take:
** establish goals;
** examine all reasonable alternatives for achieving those goals with the expectation that the
least-harmful approach will be preferred;
** shift the burden of proof to the proponents of new approaches -- they bear the burden of
producing information about the consequences of their proposed activities, monitoring and
reporting as time passes, paying for any harm that ensues and taking steps to remediate as
needed;
** those who will be affected by the decision should participate in making the decision
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Corollaries of this last point include:
*** science is not the only valid way of knowing; other kinds of knowledge can be useful to
decision-makers: historical knowledge, spiritual knowledge, local knowledge, community
preferences, cultural values, artistic perceptions, etc.
*** democratic decision-making means involving the public in the earliest stages of a project,
when the first questions are being asked and goals are being set.
Ultimately, the goal of a precautionary approach is to make decisions today that we will not regret
in 50 years.
III. Precautionary guidance for toxic site cleanups
Initial thoughts:
1) All reasonable alternatives should be considered. This approach is written into the Superfund
law, as well as the National Environmental Policy Act of 1969.
2) Affected parties should be represented in making the decision. This is fundamental to
decision-making in a democracy. Of course we want to be informed by the best science available,
but when it comes to making public policy, scientists are on a par with other citizens. As the
European Union said in 2000, "Science should be on tap, not on top."
3) Intergenerational equity should be considered. By saving money today, are we diminishing
the future for our children, reducing their options, saddling them with economic, environmental or
health burdens that we rightfully should bear?
4) When we choose a "containment" strategy -- whether a cap or a landfill or some other
containment structure -- we can ask, "What is the estimated duration of the hazard" and
"What is the estimated duration of the containment structure?"
One way to approach this is to estimate the duration of the containment by asking those who supply
the materials for the structure how long they will warranty the materials. This is particularly easy to
do in the case of geotextiles and other polymeric barriers -- how long will the manufacturers
warrant that such materials will retain their integrity? Even the suppliers of clay barriers might be
asked this question.
What should we do if we cannot estimate the duration of the hazard? What assumptions should we
make?
5) We also might ask ourselves, who will fund the long-term future of this containment,
processing or monitoring? The U.S., as a member of the Organization for Economic Cooperation
and Development (OECD) in 1974 agreed to the principle that, "The polluter shall pay." What
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happens if the polluter for some reason defaults? Who will continue the funding? Is insurance
available in such situations? If not, why not?
6) If our chosen option requires containment, processing (such as pumping groundwater),
and/or monitoring for 50 years or more into the future to safeguard the environment and
human health, we can ask, "What experience do humans have maintaining vigilance over
managing local hazards on this time-scale?" What evidence can we offer to show that human
institutions can reliably maintain funding, focus, personnel and commitment to processing, or
monitoring problems of toxic wastes for two generations (50 years) or longer?
7) We can ask, about any decision, if it eventually becomes clear that things are going badly,
will we be able to take corrective action, or reverse course? (For example, what happens if a
landfill's liners are breached? As a practical matter, can the waste be removed so that the liner can
be repaired or replaced?)
8) We can try to learn from a Superfund cleanup.
What can we learn from a Superfund cleanup?
a) We can learn that many Superfund sites were created by firms that now say they cannot
afford to clean up their toxic wastes. To deter such firms, ecological economist Robert Costanza
has proposed a "precautionary principle polluter pays" (4P) assurance bond.[13, pgs. 209-215.]
Using the "4P" approach, before a new technology, process or chemical could be introduced, the
worst-case harm would be estimated in dollar terms. Then the proponent of the new activity would
be required to post a bond for the full amount before startup.
Such "assurance bonds" are common in the construction industry today, to assure that a job will be
completed on schedule and they are intended to keep "fly by night" firms out of the construction
business where they might cut corners and endanger public health.
A "4P" bond effectively shifts the burden of proof onto the proponent -- if harmlessness could be
shown as time passed, some or all of the bond would be returned (with interest). A "4P" bond
would also give the proponent powerful financial incentives to reduce the worst case damages by,
for example, adopting intrinsically less-damaging alternatives. The "4P" bond would also give the
proponent a financial incentive to continually examine the effects of the new activity -- if damages
could be shown to be less than the worst-case estimate, part of the bond could be returned (with
interest) but the burden of proof for such a showing would remain with the proponent.
b) Examine the industrial process(es) that created the problem, and look around the nation
(world?) for similar processes that are likely creating similar problems. Take steps to avoid
continued degradation.
c) Examine the characteristics of the chemical substances that are causing the problem at this
site and take precautionary action to prevent those substances from causing similar problems
elsewhere.
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Example: In 1992, the International Joint Commission (IJC, formed by the 1910 Boundary Waters
Treaty between the U.S. and Canada to manage the waters of the Great Lakes) began to develop
biological criteria for managing chemicals. (See
http://www.ijc.org/php/publications/html/6bre.html )
** Biological criteria for environmental decisions:
In their joint 1978 Water Quality Agreement, the U.S. and Canada defined a "toxic substance" as "a
substance which can cause death, disease, behavioral abnormalities, cancer, genetic mutations,
physiological or reproductive malfunctions or physical deformities in any organism or its offspring,
or which can become poisonous after concentration in the food chain or in combination with other
substances." The International Joint Commission (IJC) defined "persistent" chemicals as those
having a half-life of 8 weeks or longer. The half-life is defined as the time it takes for half of any
substance to degrade once it has been released into the environment.
The IJC's biological criteria:
Synthetic chemicals should be eliminated if they are toxic or persistent in the environment.
Synthetic chemicals that bioaccumulate should be eliminated.
A substance bioaccumulates if its concentration increases as it moves through the food chain. For
example, DDT may be found at one ppm (part per million) in fish and at 10 ppm in fish-eating
birds. Thus DDT bioaccumulates and therefore would be a candidate for elimination.
The Natural Step.
The Natural Step offers another set of criteria for judging "sustainability."
The Natural Step was invented by a Swedish pediatric oncologist, Karl-Henrik Robert, with
assistance from a physicist, John Holmberg. Robert, a respected cancer researcher, concluded in the
mid-1980s that humans are destroying the natural environment because they lack fundamental
principles for making decisions about technologies.
The Natural Step defines four "system conditions" that must prevail for a society to be sustainable.
(http://www.naturalstep.org/ )
System condition #1: In order for a society to be sustainable, nature's functions and diversity
will not be systematically subject to increasing concentrations of substances extracted from
the Earth's crust.
System condition #2: Nature's functions and diversity will not be systematically subject to
increasing concentrations of substances produced by society.
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System condition #3: Nature's functions and diversity must not be systematically
impoverished by physical displacement, over-harvesting, or other forms of ecosystem
manipulation.
System condition #4: Resources must be used fairly and efficiently in order to meet basic
human needs globally.
d) Ask whether the problems at this site are technical problems or problems of human
behavior (or both) and then, based on this analysis, consider steps appropriate to alleviating
the problems(s).
e) What else could we learn from a cleanup?
9) Principles for Making Decisions Under Uncertainty
From Donald Ludwig, Ray Hilborn and Carl Walters,, "Uncertainty, Resource Exploitation, and
Conservation: Lessons from History," Science Vol. 260 (April 2, 1993), pgs. 17, 36.
This excellent and important short paper is available at
http://www.rachel.org/library/getfile.cfm?ID=201
"Most principles of decision-making under uncertainty are simply common sense."
1. Consider a variety of plausible hypotheses about the world;
2. Consider a variety of possible strategies;
3. Favor actions that are robust to uncertainties;
4. Hedge
5. Favor actions that are informative
6. Probe and experiment
7. Monitor results
8. Update assessments and modify policy accordingly
9. Favor actions that are reversible
========================
Notes and References
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[1] Theodore Taylor and Charles Humpstone, Restoration of the Earth (New York: Harper and
Row, 1973).
[2] D. Ludwig and others, “Uncertainty, Resource Exploitation, and Conservation: Lessons from
History,” Science Vol. 260, No. 5104 (1993), pgs. 17-18. Available at:
http://www.rachel.org/library/getfile.cfm?ID=201
[3] Mary O'Brien, Making Better Environmental Decisions; An Alternative to Risk Assessment.
Cambridge, Mass.: MIT Press, 2000.
[4] David O. Carpenter and others, “Understanding the Human Health Effects of Chemical
Mixtures,” Environmental Health Perspectives Vol. 110 (Supplement 1), pgs. 25-42.
[5] Wade V. Welshons and others, "Large Effects from Small Exposures. I. Mechanisms for
Endocrine-Disrupting Chemicals with Estrogenic Activity," Environmental Health Perspectives
Vol. 111, No. 8 (June 2003), pgs. 994-1006. Low-dose effects, including some non-monotonic
(inverted-U-shaped) dose-response curves, were described in Low-Dose Peer Review Panel,
National Toxicology Program's Report of the Endocrine Disruptors Low-Dose Peer Review
(Research Triangle, N.C.: National Toxicology Program, 2001) available as an 8-megabyte file
from http://ntp-server.niehs.nih.gov/htdocs/liaison/LowDoseWebPage.html . And see "Paracelsus
Revisited -- Part 2" in Rachel's Environment & Health News #775 at
http://www.rachel.org/bulletin/index.cfm?issue_ID=2271 . On hormesis, see, for example, Edward
J. Calabrese and Linda A. Baldwin, "Toxicology rethinks its central belief," Nature Vol. 421 (Feb.
13, 2003), pgs. 691-692, and see Rebecca Renner, "Redrawing the Dose-response Curve,"
Environmental Science & Technology (Mar. 1, 2004), pgs. 90A-95A.
[6] For example, see Beverly S. Rubin and others, "Perinatal Exposure to Low Doses of Bisphenol
A Affects Body Weight, Patterns of Estrous Cyclicity, and Plasma LH Levels," Environmental
Health Perspectives Vol. 109, No. 7 (July 2001), pgs. 675-680. See also K.S. Landreth, "Critical
windows in development of the rodent immune system," Human and Experimental Toxicology Vol.
21, Nos. 9-10 (Sep-Oct, 2002), pgs.493-498; and M.C. Garofolo and others, "Developmental
toxicity of terbutaline: Critical periods for sex-selective effects on macromolecules and DNA
synthesis in rat brain, heart, and liver," Brain Research Bulletin Vol. 59, No. 4 (Jan. 15, 2003), pgs.
319-329; and T.A. Lindsley and L.J. Rising, "Morphologic and neurotoxic effects of ethanol vary
with timing of exposure in vitro," Alcohol Vol. 28, No. 3 (Nov., 2002), pgs. 197-203; M.R. van den
Heuvel and R.J. Ellis, "Timing of exposure to a pulp and paper effluent influences the
manifestation of reproductive effects in rainbow trout," Environmental Toxicology and Chemistry
Vol. 21, No. 11 (Nov., 2002), pgs. 2338-2347.
[7] Quoted in Anthony B. Miller and others, Environmental Epidemiology, Volume 1: Public
Health and Hazardous Wastes (Washington, DC: National Academy of Sciences, 1991), pg. 45.
[8] William Ruckelshaus, “Risk in a Free Society,” Risk Analysis. Vol. 4, No. 3 (1984), pgs. 157162. Available at http://www.rachel.org/library/getfile.cfm?ID=361
11
[9] Poul Harremoes and others, Late lessons from early warnings: the precautionary principle
1896-2000 [Environmental Issue Report No. 22] (Copenhagen, Denmark: European Environment
Agency, 2001). Available at (3-megabyte file): http://www.rachel.org/library/getfile.cfm?ID=301
[10] Peter M. Vitousek, and others. "Human Appropriation of the Products of Photosynthesis,"
Bioscience Vol. 36 No. 6 (June, 1986), pgs. 368-373. And Peter M. Vitousek and others, "Human
Domination of Earth's Ecosystems," Science Vol. 277 (July 25, 1997), pgs. 494-499; available at
http://www.rachel.org/library/getfile.cfm?ID=200 And see Jane Lubchenco, "Entering the Century
of the Environment: A New Social Contract for Science," Science Vol. 279 (Jan. 23, 1998), pgs.
491-497, available at: http://www.rachel.org/library/getfile.cfm?ID=203
[11] David Pimentel and others, "Environmental and Economic Costs of Soil Erosion and
Conservation Benefits," Science, Vol. 267, No. 5201. (Feb. 24, 1995), pp. 1117-1123.
[12] Stuart L. Pimm and others, "The Future of Biodiversity," Science Vol. 269 (July 21, 1995),
pgs. 347-350.
[13] Robert Costanza and others, An Introduction to Ecological Economics (Boca Raton, Fla.: St.
Lucie Press, 1997).
[14] David Kriebel and others, “The Precautionary Principle in Environmental Science,”
Environmental Health Perspectives Vol. 109, No. 9 (September 2001), pgs. 871-876. Available at
http://www.rachel.org/library/getfile.cfm?ID=170
[15] Peter Manus, "To a Candidate in Search of an Environmental Theme: Promote the Public
Trust," Stanford Environmental Law Journal Vol. 19 (May 2000), pg. 315 and following pages.
Available at http://www.rachel.org/library/getfile.cfm?ID=234
[16] James T. Paul, "The Public Trust Doctrine: Who Has the Burden of Proof?" Paper presented
July, 1996 in Honolulu, Hawaii, to a meeting of the Western Association of Wildlife and Fisheries
Administrators. Available at http://www.rachel.org/library/getfile.cfm?ID=190
[17] The Wingspread Statement on the Precautionary Principle (1998) can be found here:
http://www.rachel.org/library/getfile.cfm?ID=189
[18] Rio Declaration (1992) available at:
http://www.un.org/documents/ga/conf151/aconf15126-1annex1.htm
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