Too Little, Too Late: The Folly of Risk Assessment
Fair Use Statement
The following Rachel's Environment & Health BiWeekly says that it could take as long as 85,000 years to figure out the synergistic effects of combinations of 3 of only 10% of the 80,000 chemicals now in use. This is unacceptable. Some call for invoking the "precautionary principle." You may also wish to read about the precautionary principle.
RACHEL'S ENVIRONMENT & HEALTH BIWEEKLY #707
---September 7, 2000---
MODERN ENVIRONMENTAL PROTECTION--PT. 4
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MODERN ENVIRONMENTAL PROTECTION--PT. 4
A recent report from the British Royal Society confirms that some
common industrial chemicals, released into the environment, can
interfere with hormones in living things with devastating
effect. Such chemicals are "cause for grave concern," the
report says. The Royal Society is the United Kingdom's national
academy of sciences, founded in 1660.
In humans and other animals, hormones act as chemical messengers
that control much of life. The system of control by hormones is
known as the "endocrine system." A recent report from U.S.
Environmental Protection Agency (EPA) described the endocrine
system this way: "An endocrine system is found in nearly all
animals, including mammals, non-mammalian vertebrates (e.g.,
fish, amphibians, reptiles, and birds), and invertebrates (e.g.,
snails, lobsters, insects, and other species). The endocrine
system consists of glands and the hormones they produce that
guide the development, growth, reproduction, and behavior of
human beings and animals.... Disruption of this complex system
can occur in various ways. For example, some chemicals may mimic
a natural hormone, 'fooling' the body into over-responding to the
stimulus or responding at inappropriate times. Other chemicals
may block the effects of a hormone in parts of the body normally
sensitive to it."
Substances that interfere with the endocrine system are called
"endocrine disrupting chemicals" or EDCs. The Royal Society's
report says that we should take EDCs seriously because there is
irrefutable evidence that some EDCs have had devastating effects
on wildlife, and the endocrine system of humans is similar to
that of wildlife. The report gives two examples of EDCs harming
1. Tributyl tin (TBT) is a highly toxic form of the familiar
metal, tin. TBT was introduced in the mid-1960s in marine
anti-fouling paints, to prevent growth of crustaceans (e.g.,
barnacles) on the bottoms of ships. By 1970, biologists studying
the English coast reported female shell fish (dog whelks) growing
male sex organs. Soon after, biologists studying the Connecticut
coast found female snails growing penises. By 1981, this
condition -- known as imposex -- was traced to pollution from
boats and ships. Laboratory experiments confirmed that TBT could
indeed cause female molluscs to develop male sex organs.
The imposex effects of tributyl tin have now been reported
worldwide -- in the UK, New Zealand, Japan, and Alaska. Over 100
species of molluscs have been adversely affected by tributyl tin
and in some cases imposex has led to population declines and even
extinction of species. The Royal Society draws important lessons
from the TBT story:
"The example of the 'TBT story' shows that the effects of TBT
were completely unexpected and unpredicted, despite legislation
governing new chemicals; nobody foresaw that TBT would cause
endocrine disruption in molluscs." The Society says, "...[T]he
effects were first discovered by accident by field biologists.
This suggests that, until our understanding of how, and what,
chemicals cause endocrine disruption improves very considerably,
it is likely that other unexpected cases of endocrine disruption
in wildlife will become apparent. This example also highlights
the difficulty of predicting what effects a chemical will have in
the wider environment where it may mix with other chemicals, get
degraded, or come into contact with a variety of species of
animals and plants," the Royal Society says.
2. The Royal Society then recounts the discovery that some fish
in all UK rivers and streams are now intersex -- having
characteristics of both males and females. The story began nearly
20 ye ars ago with the chance discovery that 5% of the roach (a
species of fish) living in two sewage lagoons were "grossly
intersex." A nationwide survey revealed that all sewage effluents
had the ability to feminize fish.
Eventually, scientists learned that the problem originated with
individual humans discharging natural estrogens and the synthetic
estrogens found in contraceptive pills directly into sewage. The
Royal Society notes that estrogens were present in sewage
effluent at "extremely low concentrations (parts per trillion)"
-- but these extremely low levels were sufficient to feminize
male fish. The Royal Society goes on: "Studies on wild
populations of freshwater fish have shown that intersex fish are
present in most rivers. In some of the poorer quality rivers,
which receive large inputs of effluents from STWs [sewage
treatment works], all of the male fish were intersex to varying
degrees. Interestingly, the rivers containing the most severely
affected fish also received significant inputs of industrial
effluent, and hence it has not been possible to completely
exclude a contribution from industrial chemicals in at least some
cases of intersexuality in fish.... It is likely that many
chemicals in the environment, possibly interacting with one
another, cause this condition in fish," the Royal Society says.
The Royal Society then discusses regulations to control EDCs: "To
date, essentially all research on EDCs has been driven by effects
(or purported effects) many of which have caused public concern
and made sensationalist stories in the media. Thus, for example,
the possible decrease in [human] sperm counts was very
influential in highlighting the human issues, while intersex fish
helped to highlight the wildlife aspects of the EDC issue. This
is an extremely slow (and costly) way of going about things; when
an effect is observed, research is then carried out to determine
the cause. Because our understanding of the environment is very
incomplete, there will always be a role for approaching many
issues in this way. However, it would be more logical to start
with a chemical, and make an assessment of what effects, if any,
it will induce. This is the aim of toxicity testing," the Royal
However, the Society identifies problems with the
chemical-by-chemical approach: "The problem with starting with
the chemical is that there are over 80,000 man-made (let alone
natural) chemicals in everyday use. In turn, these will degrade
in the environment to even more chemicals. Our knowledge of
degradation processes (in the environment, but also within humans
and wildlife) is often very poor...."
Then, in a key phrase, the Society says, "In order to develop
policy and legislation to protect humans and the environment from
EDCs it is first necessary to determine the risk of harm to human
health and the environment." The Royal Society then suggests what
is needed to complete risk assessments:
(a) Identify chemicals that have endocrine-disrupting properties.
Because current tests cannot reliably identify
endocrine-disrupting chemicals, new tests must be developed.
(b) With new tests in hand, we must then test each individual
chemical AND "interaction between chemicals that do not have
endocrine disruptive effects individually, but might in
combination." Testing combinations of chemicals is essential, the
Society says, because, "In reality, humans are exposed not to a
single endocrine disrupter but to a 'cocktail' of such chemicals,
and the possibility that such chemicals have additive or
reinforcing effects (e.g. combination of an oestrogenic with an
anti-androgenic compound) has to be considered seriously."
(c) Next we must examine the length of time these chemicals are
in the environment, the Society says.
(d) Next we must analyze the breakdown byproducts of these
chemicals, the Society says.
(e) Next we must determine the levels of exposure of humans and
wildlife to these chemicals, the Society says;
(f) And finally we must determine the levels at which these
chemicals are likely to cause adverse effects, the Society says.
So there you have it. A perfectly rational solution to the
problem of EDCs, based on the very best science. Who could argue
against such a program?
But wait. While this testing is going on, all the same chemicals
will be spewed into the environment because the current
philosophy of "environmental protection" says chemicals can't be
controlled before risk assessments have been completed. Under
this assumption, just how long will it be before we can protect
ourselves and wildlife from EDCs?
To estimate the time involved, let's examine what it would take
to test combinations of chemicals to see if, together, they cause
endocrine disruption. There are documented instances of chemicals
behaving in precisely this fashion [REHW #384 ], so the Royal
Society has identified an important goal. Suppose we wanted to
test just 10% of commercial chemicals, or 8000 chemicals, in
combinations of three. How many combination of three chemicals
can you make out of 8000 chemicals? The answer is 85 billion.
Let's assume we could test one million different combinations
each year -- surely a preposterous overestimate of human
scientific capacity. It would then take 85,000 years to complete
the tests. In other words, the Royal Society's rational program
based on the very best science will NEVER protect wildlife,
humans or the environment from damage.
It looks to us as if the U.S. EPA's Endocrine Disruptor Screening
Program (EDSP) is cut from similar cloth: developing new tests to
examine 15,000 chemicals, to discern EDCs from non-EDCs, then
requiring risk assessments on each of the individual EDCs.
Even though the EPA program seems ambitious, it leaves out far
more than it includes, e.g., EPA says there are 50 important
hormones in humans, but the EDSP is only testing three of the
50. The EDSP is ignoring byproducts and breakdown products of
the 15,000 chemicals. Furthermore, the EDSP is ignoring
combinations of chemicals. This EPA program will employ an army
of scientists for a decade -- and probably far longer. It will
generate "an immense amount of data" but "the difficulty will be
in interpreting these data," the Royal Society points out. The
chemical manufacturers will have one interpretation of the data
and public health specialists will have a different
interpretation. Ultimately, they will resolve their differences
in court. Who will have the advantage in this contest? If EPA
ever successfully bans more than 2 or 3 chemicals in the next 30
years based on this program, we will be very surprised.
There is a glimmer of hope in the Royal Society's report. After
reviewing conflicting evidence linking EDCs to testicular cancer,
abnormal penises, breast cancer and other human diseases, the
Society says, "Despite the uncertainty, it is prudent to minimise
exposure of humans, especially pregnant woman, to EDCs."
How would precautionary action work? It would begin by shifting
the burden of proof onto the purveyors of chemicals. As Joe
Thornton has suggested (REHW #704), chemical manufacturers should
be given several years in which to make a reasonable
demonstration of no hazard for each of their chemicals (including
its associated byproducts and breakdown products), to show that
each is neither persistent nor bioaccumulative, nor carcinogenic,
nor mutagenic, nor disruptive of intracellular signalling (by
hormones, neurotransmitters, growth factors, cytokines, and so
on), nor toxic at low doses to development, reproduction,
immunity, or neurological function. Testing should occur on
multiple generations of sensitive species of animals, unless
testing on less than whole animals can give equivalently useful
and reliable results. These are the sorts of tests required of
new medical drugs.
Any chemical not passing these tests would be automatically
phased out from commercial use within a decade or so. Displaced
workers would be offered funds for retraining.
The Royal Society's report -- though clearly not intending to --
eloquently shows that the current appproach to environmental
protection cannot protect anyone or anything except the chemical
industry. We must adopt a modern precautionary approach.
 Patrick Bateson and others, ENDOCRINE DISRUPTING CHEMICALS
(EDCs) (London: The Royal Society, June 2000). To locate a PDF
version of the report on the web, go to
http://www.royalsoc.ac.uk/policy/index.html, click on "reports
and statements," then search for "endocrine disrupters."
 U.S. Environmental Protection Agency, ENDOCRINE DISRUPTER
SCREENING PROGRAM REPORT TO CONGRESS (Washington, D.C.: U.S.
Environmental Protection Agency, August 2000). Available on the
 Joe Thornton, PANDORA'S POISON; CHLORINE, HEALTH, AND A NEW
ENVIRONMENTAL STRATEGY (Cambridge, Mass.: MIT Press, 2000), pg.
359. ISBN: 0262201240.
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