c/EPA
United States
Environmental ?'0taction
Agency
Office of
TOXIC Substances
Washington, DC 20460
EPA-560," 2-73-003
April 1980
Substances
Toxic Substances:
A Brief Overview of
the issues Involved
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TOXIC SUBSTANCES:
A Brief Overview
of the
Issues Involved
(This publication was prepared, under a Grant from the U S
Environmental Protection Agency, by the New Jersey Public
Interest Research Group (NJPIRG) in cooperation with the
New Jersey League of Women Voters)
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CONTENTS
INTRODUCTION: Toxic Substances: A Brief Overview I
BIOLOGY: DNA and All That. 9
CHEMISTRY: Name That Toxic! 13
PHYSIOLOGY: How the Toxic Substances Sneak Past Your
Skin and Liver. 15
ECOLOGY: Where the Toxics Hide in the World.
Toxics Moving and Influencing the Environment. 18
ANALYSIS: Risk: A Very Theoretical Solution to a Very
Real Problem. 20
LAW AND TOXICS 23
AN EXTENSIVE BIBLIOGRAPHY 26
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INTRODUCTION
TOXIC SUBSTANCES
A Brief Overview
by Robert Dahl, NJPIRG
This pamphlet contains an introduction to some of the basic issues
involved with the control of toxic substances. It is hoped that anyone
unfamiliar with the field will find it easily understandable, but it is
suspected that specialists in related fields will find it somewhat brief:
It is intended to be a starting point, not the final word. There is
suggested additional reading, which is also general in nature. The pam-
phlet offers: Useful definitions of pollution and toxics; A categoriza-
tion of toxics by both chemical properties and effects; A review of the
problems in detection and identification of low-level ubiquitous toxics;
and perhaps most important, an exposition that toxics are not a new look
at an old .problem, but are a whole new problem.
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Toxic Substances - A Fundamental Change in Pollution Problems
Man's pollution of his environment is not new—it may, in fact, be
intimately associated with the species known as "intelligent man". When
man began to make tools and purposely alter his environment, he became a
generator of pollution. In the Introduction to the Reference Encyclo-
pedia of Ecology and Pollution, Rene Dubos states that "contrary to gen-
eral belief, (pollution) problems do not result from the fact that
modern man suddenly acquired wasteful and careless habits...The arti-
facts made of stone, ivory, or pottery which litter prehistoric sites
are the equivalent of gadgets, plastic containers, and aluminum cans
with which we litter our landscape. There is no evidence that we are
more wasteful than our prehistoric ancestors...what is certain is that
our wastes and pollutants are chemically different from those of the
past".
Before the Industrial Revolution, most wastes were easily biode-
graded because they were made from 'natural1 materials. These materials,
such as sewage, wood, and leather, had been present in the environment
for a long time. Bacteria, insects and other decomposers were pre-
adapted (from ages of decomposition of bio-materials in normal trophic
interactions) to break down these wastes. Indeed, care must still be
taken to keep decomposers out of the wooden frame of a house, or a
favorite pair of leather shoes.
In the last hundred years, however, there have been great advances
in knowledge on nearly all fronts, particularly in our ability to use
and manipulate chemical substances to produce materials with nearly any
desired properties. .Certainly man has benefited greatly from this
ability, but as these products are produced, distributed and consumed,
their ultimate destination is a return to the environment at large.
Many of these substances and their associated byproducts are totally new
to the world, and there are, therefore, no decomposers equipped to
handle them. Some substances are elements, such as metals, and are
simply not decomposable. Since these substances are continuously pro-
duced, and decompose slowly if at all, they accumulate. As they accumu-
late they may affect the functioning of ecological systems, including
the ecology of human beings. Rene Dubos continues: "like other organisms
in nature, human beings are ill-equipped biologically to deal with many
of the man-made substances produced by modern technology...We have no
instinct or organ to warn us of the dangers that lurk in an invisible
beam of radiation or In toxic substances which are tasteless and odor-
less in the concentrations commonly found in the so-called normal envir-
onment of technological societies".
The goal of controlling man-made toxic substances in our environ-
ment cannot be thought of as part of a 'back to nature' movement, which
implies that we were once cleaner than we are now. Man has always been
a polluter; in the past he changed the degree or amount of decomposition
necessary, today he Is changing the kind of decomposition necessary.
Nature is not equipped to do that decomposition, so man must do it him-
self. This demands a fundamental change in man's philosophy and relation
to his environment.
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Pollution vs. Toxicity - an attempt to define terms.
The words 'pollutant' and 'toxicant1, two terms for substances
which can be toxic, are often used interchangeably. This is not surpris-
ing because both words have a broad range of meaning in general use. It
is helpful and realistic, however, to assign at least somewhat more
exact meanings to these words—even though these definitions must necess-
arily overlap to some degree.
When we speak of a toxic substance, we are speaking of any material
which will inhibit or destroy the normal functions of living tissues
when that tissue Is exposed to a specific dosage for a specific duration.
This inhibition of function may occur very quickly or may take several
decades to develop.
We may speak of the air being polluted with high levels of carbon
dioxide, even though this compound is normally present in low concentra-
tions, and is vital for photosynthesis in green plants. A lake may be
polluted by an over-supply of phosphates, whereas if^all the phosphate
were removed the lake would become as lifeless as the rock beneath it.
This is perhaps the best definition of a classic pollutant: a substance
which is essential and beneficial in nature, but is harmful in elevated
concentrations. Pollutants generally become toxic when concentrations
reach the parts per million (ppm) range.
Toxicants may be regarded in the same light, but the range of
concentrations which are not harmful becomes vanishingly small, or
disappears altogether. Toxicants are active in the parts per billion
(ppb) range.
Chemical Categories of Toxics
Host toxic substances can be placed into one of several general
categories on the basis of their chemical properties. These categories
overlap widely.
Metallic elements and compounds—such as lead, mercury, and cadmium.
Since metals are elements, they are not biodegradable.
Small organic and inorganic molecules—such as nitrates, sulfur
oxides, and carbon monoxide. Most of these are normally present, but
become problems at higher concentrations.
Larger organic compounds—such as benzene, PCB's, phthalates, and
most pesticides. These compounds are not normally present, and very low
concentrations may be harmful.
Radioactive wastes—while not directly entering Into and disturbing
chemical reactions, do exert a chemical effect. As a radioactive iso-
tope of an element decays into a non-radioactive isotope, it gives off a
high-energy particle which may Interact with many molecules along its
path. The interactions generally Impart some energy to the molecules—
allowing them to undergo reactions which are not possible under normal
condi tions.
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Thus, most small organic and inorganic compounds are pollutants
which may become toxic by virtue of elevated concentrations, while
metals, large organics and radioactive isotopes can be viewed as toxic
substances at almost any concentration.
The Effects of Toxics
When the concentration of a toxic substance becomes high enough,
through intentional or accidental release or assimulation, it may cause
immediate (acute) effects. These unfortunate events have the benefit of
facilitating the correlation of a specific toxin and its symptoms. More
often, however, the toxin is present in low (but still active) concentra-
tions, which may not cause symptoms to appear immediately. This is
known as 'chronic1 exposure, and the delay between exposure and the
appearance of symptoms is called the latency period. The phenomena of
chronic exposure and a latency period make it very difficult to corre-
late specific symptoms with specific chemicals. Extensive testing may
be needed, in which the chemical is administered in what is judged to be
an acute dose (to bacteria or mice). Even if toxicity is established,
the exact mechanism of toxicity may be difficult or impossible to
elucidate—either due to our lack of complete understanding of the
chemical interactions of life, or due to the non-specific action of the
toxin. Toxins are generally assigned to one or more of the following
categories:
Mutagens - Cause random changes in the information stored in the
DMA, the genetic material of nearly all living things. While cells
possess systems for the correction of mutations (indeed some cells have
systems for causing mutation—with vital functions protected), once the
mutation is complete the information is changed. As with any finely
tuned system, a change is more likely to be harmful than good, although
it is often neutral.
Carcinogens - cause the unrestricted proliferation of abnormal
cells which we call cancer. Mechanisms seem to be mutagenic in some
cases, but are largely unknown.
Teratogenlc - causing birth defects and abnormalities. The classic
example is the sedative drug Thalidomide, which was identified as the
causative agent in a number of similar deformed births. Thalidomide was
subsequently shown to fae teratogenlc, carcinogenic and mutagenic.
General toxins - which may affect various life functions. A good
example Is Mercury, which Is known to react with the sulfhydril groups
in proteins. These groups play a major role in the three-dimensional
configuration of large protein molecules. The biochemical activities of
these proteins are defined by their ability to recognize other molecules
by their three-dimensional characteristics. Changes in the shape of the
protein may reduce or destroy that ability. General toxins may cause
anything from discomfort, headaches and indigestion, to behavioral
changes, neurological damage and death.
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Problems in the Detection and Identification of Toxics.
A partial list of problems likely to arise in any investigation of
a suspected toxic chemical includes:
- Toxins may be active in concentrations too low to be detected by
qualitative analysis. For example, it is not clear whether hexachlor-
ophene is itself toxic, or is laced with minute undetectable impurities
of the ultra-toxic dioxins.
- Latency between exposure and expression of symptoms makes it
difficult to correlate a specific toxin and its effects. For instance,
asbestos usually takes 20-30 years to show its effect.
- Chemically related compounds may have nearly the same toxicity,
or very different toxicities. This makes it very difficult to predict
which chemicals are likely to be dangerous.
- Synerglstic effects - two toxins (or even non-toxins) may inter-
act in such a way that they are far more toxic when together than would
be expected on the basis of their toxicity when present alone.
Resolution - There are many chemicals in use today to which
people are commonly exposed. This makes correlation of specific chem-
icals to specific effects even more difficult.
- Natural toxification - relatively non-toxic compounds may be
made more toxic by the body's detoxification systems. Tom Eisner, a
biologist at Cornell University, tells an interesting "natural history"
story on this subject. Many plants produce toxins for protection against
insect herbivores. Many insects, in turn, have evolved a detoxification
system which allows them to eat the toxic plants. He has found that
some plants now produce non-toxic chemicals which are rendered toxic by
the insect's already existing detoxification mechanism.
Ignorance of toxic mechanisms make scientific study difficult.
- Scientific testing procedure is designed in such a way that
false results are given with a certain frequency (there is a trade-off
here between having tests sensitive enough to find small yet real diff-
erences; and avoiding false positive results due to normal random varia-
tion in results) .
- Toxics are useful in some cases, and are produced because people
need or want them or things they help produce. Hexachlorophene is an
excellent example; It was widely used as an anti-bacterial cleanser, but
was found to cause brafn damage when used in high concentrations. It
is, however, excellent in fighting staphylococci in specific situations.
The decision was made to classify hexachlorophene as a drug, so that it
may only be used when the benefits out-weigh the costs. It is still
used to fight staphylococcf, But not diaper rash.
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Decision Making: What Level of Risk is Acceptable?
- In the decision process to determine whether the use of a sub-
stance constitutes an unacceptable risk, traditional methods of cost/
benefit analysis break down, because important parameters are not well
known. For instance, there is a 'zero/infinity1 paradigm, meaning that
the probability of an event is near zero, but the potential cost of that
event approaches infinity. A good example of this is the problem of
accidental nuclear reactor core meltdown—which would release large
amounts of radioactive material into the environment. Advanced tech-
nology can reduce the chance of this happening to near zero, but the
potential cost remains high (and may even get higher, since an ever more
costly piece of equipment is destroyed). Cost benefit analysis talks in
dollars and cents, but it is difficult to estimate the value of such
things as clean water, pleasant surroundings, good health, and a clear
night sky.
The presence of toxic substances in the ambient environment is a
problem of our entire society. At present, however, small segments of
the society are making the significant decisions (or lack of decisions)
for the entire society. Scientists evaluate the effects of toxics, and
may make recommendations regarding decisionmaking, but the actual power
to make and enforce decisions rests with various government agencies.
As mentioned above, the usual method of governmental decisionmaking
is cost/benefit analysis. Costs and benefits of an action are estimated,
and if the benefits exceed the costs, the action is carried out. This
system sounds extremely simple, and it can be. Problems generally
arise, however, because to facilitate comparison both costs and benefits
must be translated into a common currency: the arbitrary units of
dollars and cents. There may be wide disagreement on the value assigned
to a certain cost or benefit, and special interest groups may seek to
reduce or inflate the assigned values in an attempt to tip the scales in
their favor.
In the regulation of toxic substances, cost/benefit is reduced to
the concept of "acceptable risk". Actuarials determine the level of
risk which the population seems to accept (e.g. driving cars), and
assumes that comparable environmental risks will be acceptable. One
major flaw in this system is that there is a large data base for accur-
ate estimation of the risks while driving a car, but little such data
exists for the estimation of environmental and public health risks.
The other major weakness of this approach is that there is rarely
an opportunity for the general public to express its views on the level
of risk they are willing to accept. Ideally, a well-informed public
should be the primary decisionmaker in regard to the risks to which they
wi11 be exposed.
Assuming that these problems can be ironed out of the process,
there remains a large problem In the validity of one of the primary
assumptions of cost/benefit analysis. This is the assumption that
relationships are continuous—meaning that a small change in the con-
centration allowed by regulation would cause only a small change in the
costs of maintaining this level, and a corresponding small change in the
benefits expected. This may not always be the case. For example, in a
study on the carcinogenic effects of tobacco smoke (thus the study had a
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large data base, and therefore reliable figures), the following results
were found relating exposure to carcinogens (# of cigarettes per day)
with relative risk:
RELATIVE RISK
Cancer of
# Cigarettes Lung Cancer Esophagus
Non-smoker 2 I
1-10 12 3
11-20 26 3-2
21 - 30 39 3.7
31 - kO 1*5 3-8
i»l + 60 3-8
(From Wynder and Stellman, 1977. Cancer Research 37:A608-22)
With regard to lung cancer it is clear that the higher the exposure,
the greater the risk. With cancer of the esophagus, however, the results
are very different. It appears that any non-zero level of exposure is
equally bad. It is not important here that the absolute fi-gures for
cancer of the esophagus are lower than the figures for lung cancer, the
point is that according to this study, there is no completely safe lower
limit. When one considers that living in the Boston-New York-Philadelphia
area has been estimated to be equivalent to smoking on the order of 10
cigarettes a day, the implications on public health are staggering. It
is suspected that many toxic substances are in a way similar to the
effect of smoking on cancer of the esophagus--no level of exposure,
other than zero, can be said to cause no increase in the incidence of
detrimental effects. Under these conditions the previously mentioned
assumption that a small change in concentration will cause only a small
change in cost/ benefit, simply is false. Small changes at high levels
will have little effect—drastic reduction of exposure to near zero will
have a drastic effect.
It is important to note that many decisions as to level of accept-
able risk have to be made with much less data than is available in the
case of cigarette smokers. Rather than wait for future date (which may
be very long in coming), these decisions must be made to limit poten-
tially damaging exposure.
Decisions on toxic substances will still be made by government
agencies, but the Issues must be decided using different criteria,
including input from the society at large (e.g. non-special interest
groups such as the task forces in this program). In this way society
will have real influence in deciding these very real issues which have
derived from one of man's ancestral habits, and his new-found knowledge
and prosperity.
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Suggested Reading
Chemical Villains: A Biology of Pollution
James W. Berry, David W. Osgood, and Philip A. St. John. The C. V.
Mosby Company, St. Louis, 197*».
Highly recommended. This book contains excellent and understand-
able short review of ecosystem theory, biochemistry, and anatomy/
physiology. The second half of the book contains no-nonsense infor-
mation on a wide variety of Toxics. 180 pages with 89 illustrations.
North American Encyclopedia of Ecology and Pollution, edited by Wm.
White Jr. 6 Frank J. Little, Jr., North American Publishing Co.,
Philadelphia. 1972.
A collection of articles by various specialists; worth skimming
through. Rene Dubos1 Introduction is excellent.
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BIOLOGY
DNA AND ALL THAT
Introduction
In the last thirty to forty years our knowledge of the workings of
living systems has mushroomed from descriptive hand-waving to an intimate
understanding of a few of the basic bio-chemical systems of life itself.
The pollution of living systems with various toxic substances has in
some cases been shown to have specific adverse effects at specific
points in these systems. It is important that we have some understand-
ing of these systems at the molecular level, so that we better under-
stand the effects of toxic substances on our ecosystem in general, and
on ourselves in particular.
In the first half of the twentieth century, there was intense
activity in the scientific world. It was obvious that life required
large amounts of information to be stored inside each cell. This is
apparent when one considers that every human being starts life as a
single cell, and In the first nine months of existence grows into a
completely functioning, though nearly helpless, individual. The amount
of information necessary to orchestrate this development must be impress-
ive, and nearly all contained in that single, first cell.
It was known that certain parts of the cell called chromosomes are
responsible for the transfer of genetic information, but chromosomes are
made of both DNA (deoxy-ribo-nucleic acid) and proteins. The question
was: Is the information stored in the DNA or in the protein? Circum-
stantial evidence suggested that the proteins were more likely to be the
correct answer. This turned out to be dead wrong.
It has been found that the DNA contains the genetic information,
and that this Information is translated into the structure, and thereby
the function, of proteins. The story of the flow of this information is
a beautiful example of the elegance and simplicity of nature. The dis-
ruption of this system by toxic substances has widespread and irrever-
sible impact on all living things.
The Structure of DNA
Each DNA molecule is like a long chain with spurs. It has a long
backbone of repeating units, and each unit in the backbone has a side-
group (a so-called nucleotide base) projecting from it. There are four
possible side groups: Adenine, Thymene, Guanine, and £ytosene (remember
the initials, not the names). DNA molecules are virtually always pres-
ent in pairs, due to weak but significant interactions between the side
groups. Adenine prefers to be near Thymene, and Guanine pairs with
£ytosene. Thus the typical structure of a DNA molecule, or rather a pair
of DNA molecules, is with their projecting side groups aligned with A
paired with T, and G paired with C. The two backbones are on the out-
side. The two backbones have some 'spring1 in them, which makes them
twist around one another. Thus the pair of DNA molecules can be visual-
ized as a twisted ladder, with the rungs being the side groups project-
ing inward and joining, and the sides of the ladder as the backbone of
repeating units. The two molecules are 'complementary1 to one another;
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that is, if one has the sequence A T G C, its neighbor will have the
sequence T A C G. This complementarity gives DNA one of the most
important characteristics, the ability to replicate itself.
DNA Rep Iicat ion
DNA replication is schematically a very simple operation, the two
strands of DNA are separated, and a new complementary mate is assembled
for each. Both of the new ladders are exactly identical to the original.
This has been proven by the very clever use of strands of DNA which are
'marked1 with radioactive side groups. The marked strands can be follow-
ed through several generations, and in each case the old DNA material is
divided evenly between the two 'daughter1 cells.
The fact that DNA can be replicated implies the possibility that it
may be replicated incorrectly. An incorrect replication of a DNA mole-
cule is known as a mutation. A mutation may be the substitution of one
side-group for another, say A is replaced by G; or whole sections of DNA
may be moved from here to there as the backbone is broken and repaired
incorrectly. Sections of DNA may even be lost completely. Many toxic
substances are known or suspected to cause mutations. Since virtually
all living things use the DNA system, a substance which causes mutation
in one organism is likely to cause mutation in many other organisms.
Once a mutation is complete, the changed DNA is replicated as though it
were correct, since the cell has no way of knowing that it.contains an
error. These errors may have profound effects on cell systems, includ-
ing causing cancer. This is because the sequence of A T G and C side
groups on the DNA strands is the clever yet simple code used for the
storage of the information necessary in protein synthesis.
Protein Synthesis
Protein, like DNA, consists of a long chain of repeating units. In
proteins there are twenty side units called amino-acids - we will not
worry about their names. Proteins are not paired to form 'twisted
ladders', like DNA. Proteins play a wide variety of roles in all cells.
They may be structural, such as the proteins in muscle fibers; or pro-
teins may be functional, such as the digestive enzymes.
The recommended daily intake (RDA) for protein is about ^0 to 50
grams per day. This protein enters the body as long-chain proteins
produced fay some other organism, such as a corn plant, a wheat plant, or
a chicken. These long-chain proteins are of no use to a human being, so
the digestive enzymes tear the protein back down into its individual
amino-acid building blocks. The most facinating part of this story is
the use of the Information In the DNA to take these amino-acid building
blocks and put them together In a new way so that they will form a
protein which will be helpful to a human being.
The first step In protein synthesis is the generation of a DNA-like
molecule called 'messenger-RNA1 Cor MRNA for short: RNA, rjbo-nucleic
acid). This Is done by a system almost identical to that used in DNA
Feplication. First, the two strands of the DNA separate (probably not
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completely from end-to-end, only in the section that is going to be
transcribed Into RNA), but this time only one side is replicated, using
RNA building blocks rather than DNA building blocks. The MRNA strand is
peeled off, and the DNA strands are repaired. Thus the DNA is used only
as a template for making messenger-RNA. The newly-made MRNA strand is
then transported to another part of the cell, carrying the information
from the DNA. This Is why it is called Messenger RNA.
Now it gets a bit more complicated. A large protein structure
known as a ribosome accepts the MRNA strand, and with the help of energy
and special "transfer RNA (called tRNA, of course), the ribosome gener-
ates a protein. To do this, the ribosome uses twenty kinds of tRNA
molecules, one for each of the twenty kinds of ami no-acids which will
make up the protein. Each of the twenty tRNA molecules binds to one
specific amino-acid, and will also bind to a specific sequence of three
of the side groups on the mRNA. As one tRNA/amino-acid complex binds to
the beginning of the mRNA, the ribosome traps it there and waits. When
another tRNA/ amino-acid complex binds to the next three side groups on
the mRNA, the ribosome moves forward three side groups, joins the ami no-
acids together, and lets one of the tRNA's escape. The ribosome contin-
ues to shift down the mRNA molecule, three side-groups at a time, adding
another amino-acid to the growing protein with each shift. Finally the
ribosome reaches a special combination of three side groups which means
STOP. The ribosome then releases the string of ami no acids it has
generated, and releases the mRNA. It seems unbelievable, but it is
true.
To summarize protein synthesis: a section of DNA is transcribed
onto mRNA; the mRNA is translated three units at a time by ribosomes
using tRNA/amino-acid complexes; the ribosome uses cellular energy
sources to join the amino-acids together to form proteins. Thus each
three side groups of the mRNA (and therefore of the DNA itself) corres-
pond to one of the amino-acids In a protein. A mutation, or a change in
the DNA will cause a change in the sequence of amino-acids in a protein,
which potentially alters the structure of the protein and its ability to
function properly, since the structure of a protein and its function are
very closely related. The relationship between protein function and
protein structure Is the final concept needed to understand the signif-
icance of mutations in the DNA.
Protein Structure
When a protein Is produced by the process outlined above, it is
only a long string of amino-acids. The various amino-acids in the
string have different chemical properties. For example some of them are
'oily1 in nature. These are called 'hydrophobic1 (literally 'fear of
water1), because they tend to avoid being in direct contact with water
(much the same way that 'oil and vinegar don't mix1). Other groups are
hydrophyl1Ic, or 'water loving1. These differences are very important.
In the environment Inside the cell, which Is mostly water, the protein
automatically bends and folds back on Itself in such a way that as many
as possible of the' hydrophyl1ic amino-acids are on the outside. Factors
which fine-tune the folding of the protein are temperature, acidity, and
the concentrations of certain substances Inside the cell. If conditions
are correct the protein will contort itself in a very specific way, and
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by virtue of its shape and surface, the protein will become 'active' -
that is, it will have the ability to attract and hold certain specific
smaller atoms or molecules. A good example is blood hemoglobin, which
may hold either oxygen or carbon dioxide to move these gasses back and
forth between the body and the lungs.
It now becomes apparent that a mutation in the DNA will mean the
change in the activity of the protein, through the following course of
events: Mutation causes change in the sequence of side groups in the
DNA, which causes a change in the side groups in the mRNA, which causes
a change in the folding of the protein, which may change the ability of
that protein to attract and hold molecules, which means a change in the
ability of the protein to do its job.
So, where do Toxics fit In with all of this? This is certainly a
very complex system, and toxics may have their adverse effects at any
point in the system. They may cause mutations to occur more frequently;
they may cause breakdowns in the process which regulates when each
section of DNA is used; they may alter the inner cellular environment in
such a way that proteins do not have their normal shape and therefore
the proteins will not function properly; in essence, the system is so
delicate that toxic substances can interfere at any level and have an
impact on the everyday functioning of this system - a system we call
life.
Conclusions
Today, it is universally accepted that the DNA carries the genetic
information and that this information is expressed through the synthesis
of proteins, which act as the structural elements for various tissues,
and as enzymes which take part in virtually every cell reaction. Every
animal, plant, fungi, bacteria and algae on the earth relies on the
integrity of this system. Man, who is certainly one of the most extra-
ordinary examples of this system, shares unbreakable ties with every
living thing through this common chemistry of life. He is, however,
unique in his ability for self-awareness and the accumulation of know-
ledge. Man must turn this self-awareness and knowledge to look on his
actions with a more comprehensive viewpoint. The problem of toxic
substances in the environment is conspicuous- In its urgency and in its
threat to the very foundations of life itself.
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CHEMISTRY
NAME THAT TOXIC! - A step toward understanding the Chemist's Jargon
One of the problems that people face when trying to help solve the
toxics problem is the exotic jargon of chemists. Chemists are, of
course, not the only group with their own jargon: lawyers, bureaucrats,
psychologists, artists, carpenters, plumbers, and almost any other
special interest group develop their own private channel to talk on by
the use of specific words. In the final analysis they are all the same;
a carpenter speaks of headers, liners, jacks and sills, while a chemist
talks about carbon chains, hydroxyl groups, benzene rings and inorganic
salts. There are many chemicals with names; and to make matters worse,
there is often more than one name for the same chemical. It would,
therefore, be senseless to list and explain even a small fraction of
them here. Instead, we offer a short introduction to chemical termin-
ology.
Everything is composed of atoms, and an atom is mostly empty space.
Each atom has a small heavy core (nucleus) made of Protons and neutrons.
A number of light electrons are in orbits around the nucleus. The
protons in the nucleus have a positive charge, and the electrons have a
negative charge (neutrons have no charge). If an atom has as many
electrons as protons, the atom has no net charge as a whole. If there
is a shortage or surplus of electrons, the atom will have a net charge,
and may be called an ion (say eye-on). The condition of the electrons
determines the chemical properties of an atom - in fact all of chemistry
may be reduced to the Interactions of electrons of one atom with the
electrons of another atom, (if there is a change in the number of pro-
tons in the nucleus, the atom changes very severely, and becomes a
different element - for example in nuclear reactors Uranium splits into
other lighter elements such as Iodine, Argon Strontium, and others. The
altered number of protons in the nucleus effects the electrons orbiting
around it, and thus changes the chemical properties. A change in the
nucleus is a drastic and relatively rare event in nature.) If there is
a change in the number of neutrons in an atom, the atom does not change
to another element, but becomes a different isotope (literally means
'same place1) of the same element. For example carbon normally has a
total of 12 protons and neutrons \n Its nucleus -6 protons and 6 neutrons,
A certain percentage of carbon atoms have a total of 1A protons and
neutrons, 6 protons (which makes It act like other carbons), and 8
neutrons. Isotopes are Indicated by the chemical symbol with a number
in the upper right hand corner, for example Carbon U is written
others are L,1 and 1^33 Uay "fodine-one-thirty-one", and "Uranium two-
thirty-eight1^ or Just "you-two-thi rty-eight") .
Atoms may be bonded to one another to form molecules. Air is
mostly molecules of Nitrogen (two Nitrogen atoms bonded together) and
Oxygen molecules (two atoms of Oxygen bonded together). Water is a
molecule made up of one atom of Oxygen and two atoms of Hydrogen. A
method of shorthand for writing how many atoms of each element are in a
molecule has been established. The chemical symbols for the elements
are used, with a number in the lower-right corner to indicate how many
atoms of this element are present. For example water is written H^;
molecular Oxygen is 0 ; and sugar (glucose) is C^-i^g' which means
13
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six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. Note
that this system does not tell you how the atoms are hooked together.
Obviously there are many ways to arrange these 6+12+6=2^ atoms - much
the same way that different bricks can be combined in different ways to
produce walls, window sills, and front steps. For example, wood is
chemically very similar to sugar and starch, but the small differences
make it impossible for animals to digest wood.
One of the most important properties that characterizes a substance
is its ability to dissolve in various types of liquids. For example,
thanks to TV ads, everyone knows that oil and vinegar don't mix—Why is
this true? The problem is that vinegar is a "polar" substance, which
means that each molecule acts like a tiny magnet. All these magnet-like
molecules attract and repel one another, and line themselves up. Water
is polar, so other polar substances will dissolve in it rather easily.
When one attempts to mix a non-polar substance such as oil in water, it
does not work because it is difficult to get the water molecules to
separate to let the oil molecules in between them. There are different
degrees of polarity and non-polarity, so it is often possible to get two
substances which will dissolve temporarily, and then separate later as
the polar molecules slowly attract one another, as is the case with most
salad dressings. If one chooses the ingredients correctly, and mixes
properly, the ingredients will stay dissolved. Examples would be cold
cream or first-aid ointment.
The interactions of atoms and molecules are really what chemistry
is all about - and when you think about it, it becomes obvious that
these interactions depend on how two substances react when they are
close together - in fact how they 'react1 when they touch one another.
There are several other concepts which could help to understand the
chemist's jargon, but you probably already own one of the best resource
books in your own home. For example - how do you find out what trichloro-
fluroethylene really is? Divide and Conquer—and get out the dictionary!!
By looking up each section of the chemical name you can get a better
idea of what the substance Is made of. Many modern .dictionaries give
definitions for the more common chemical substances, so it is often
possible to look up the word directly. If you really get interested,
many libraries have books on Chemistry - and a good high-school text
will give the basics clearly and in enough detail that you will be able
to hold your own and understand most of the chemical buzz-words.
In conclusion, Chemistry is like any other special subject in that
it has it's own jargon. It Is worth learning a bit of this jargon, and
Is really no harder than learning what a fugue sounds like, or an Im-
pressionist painting looks like, or even how to dance Disco. Chemistry
may not make the best cocktail party conversation, but if you wish to
communicate with the various groups involved with toxic substances, your
group will be more effective and less frustrated if you can understand
some of the basic Ideas behind the big buzz words. Probably the best
strategy Is to recruit a Chemist or Chemical Engineer, or study up on
the subject - either way it will be necessary to make more detailed
investigations of various substances as they become important to you.
Hopefully, there will be effective communication between groups, so that
there will not be duplication of research efforts.
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PHYSIOLOGY
How the Body Deals With Toxics
There are three major ways toxic substances can enter the body:
through the skin, lungs, or digestive tract. A specific toxic substance
may enter the body and do damage through one route, say the digestive
tract, but may be unable to enter by another route, say the skin. It is
useful to have some understanding of how and why toxics are able to
penetrate the barriers which attempt to keep the body separate from the
outside world.
Ingest ion: Food For Thought
The material which makes up the eyes with which you read this page,
and the brain with which you understand it, had to come from the food
and water that you ate. Unfortunately, this food and water is becoming
more and more contaminated with various toxic substances.
If a toxic is present in a very high concentration - and the body
has the ability to sense Its presence - one of several mechanisms may
come into play to help reduce exposure. The taste buds may reject the
substance and motivate the person not to swallow - or if the substance
has been swallowed, the esophagus may be activated to perform the vomit
reflex - which is basically a long swallow in reverse. Unfortunately,
however, many toxic substances do not stimulate either of these re-
sponses -and the food is consumed without any immediate problems. As
the toxic substance passes through the digestive tract, one of several
things happens to it. In some cases the toxic may be unable to pass
through the walls of the intestine - and so the toxic is carried along,
and ultimately is eliminated with the feces. In this case there prob-
ably is no harm to the body, though it may irritate and cause problems
such as cancer in the lining of the stomach, intestine, or rectum. (it
is important to note here that the same substance may be harmful if
inhaled or applied to the skin rather than eaten. For example, you can
eat four packs of cigarettes a day if you like - but don't inhale them!),
If the toxic in the food or water is able to pass through the wall
of the intestine, there is the potential for greater harm. As substances
pass through this wall, they enter the blood system, and are carried to
the liver. The liver may be visualized as an active filter system which
has the ability to alter some substances in such a way that they become
either more useful or less harmful to the body. A good example is the
ability of some enzymes in the liver to isolate and remove certain
heavy metals. Unfortunately, the liver's intricate system is neither
perfect nor fool-proof; some toxics are not deactivated by the liver,
and some are even rendered more toxic by the liver.
After passing through the liver, the blood enters general circula-
tion - going to all parts of the body. It is at this stage that the
most widespread damage is possible, as chemicals travel through the
bones, nerves, glands, fat, muscle, and other tissues. As previously
mentioned the toxics will tend to accumulate in areas depending on their
specific chemical properties. Ultimately, the blood passes through the
15
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kidneys and here many toxics which have not been absorbed by other
tissues are removed from the blood. The kidneys are not perfect, they
cannot remove al1 toxic substances, and, of course, since the kidneys
remove the toxics they tend to be exposed to the highest concentra-
tions. This can lead to problems with the kidneys themselves, or other
parts of the urinary system.
Ingestion of toxics may result from various kinds of exposure. The
toxic substances may be in the food we eat, water we drink, or even in
the air we breathe. (The mucous which protects the lungs by trapping
and holding many Inhaled particles is gradually moved up the wind-pipe
and is swallowed. Thus many of the toxics in the air will find their
way into the digestive tract by riding on dust particles.) The body is
equipped to handle many of these substances, but many more are not
stopped and enter the blood system, thereby gaining access to the entire
body.
"The Air, the Air is Everywhere"*
(*from the song Pollution in the Musical "Hair".)
It is often easy to forget that air even exists. Breathing is
almost like the heartbeat: a constant fact of life which we are rarely
even aware of.
There are well over two hundred million people in the USA today,
and every one of them is eating and breathing. We have some degree of
control over the food we eat, if we object to butter for one reason or
another, we can buy margarine. For breathing, however, there is no
'substitute1 produce - the air we have is the air we must breathe.
As we breathe, air enters through the nose, passes through the
nasal cavities, on into the windpipe, and finally deep into the passage-
ways of the lungs. At each point along the way there are 'filters' to
help to keep out dust and particles. The nose hairs trap the largest
airborne particles - frequently causing a tickling sensation which
causes us to "back-flush" the system - to sneeze. Particles which are
small enough to get by the hair without triggering a sneeze may be
trapped in the mucous which lines the sinuses and windpipe. This mucous
moves constantly toward the esophagus (gullet) and is unconciously
swallowed. (Interesting to note here that by this system some airborne
toxics may become Ingested toxics.) Particles which are not stopped by
the mucuous layers pass deeper into the lungs. This is where some big
trouble can start. In order to better understand the problem, however,
it is best to side-track to explain some things about how lungs work.
The job that the lungs must perform - 21) hours a day - is to allow
oxygen to dissolve from the air Into the blood, and to let C02 dissolve
from the blood into the air. This is done by bringing the air and the
blood into close contact, in tiny sacks in the lung called aveoli. It
is important to note that the aveoli do not expand and contract with
each breath - they merely open onto passageways in which the air is
moving. A (surprizingly) good analogy may be made by comparing the air-
aveoli relationship to the postal service-residence relationship: The
postman goes by every residence every day (almost) and each trip he
16
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accepts a little mail and leaves a little mail - but he never drives
through the living room. It's the same with the aveioli. The air flows
by, not through, and with each cycle something goes out and something
comes in. The 02 and C02 drift in and out of the aveoli, but unfor-
tunately there is sometimes a little junk mail - an occasional letter
bomb.
The danger lies in that there is a range of sizes of particles
which are small enough to get past all of the filters, and yet too big
to drift in and out of most aveoli without making contact and sticking
to the aveolar wall. The problem is made more complex by the fact that
very small particles, such as individual molecules of some volatile
toxic substances, may pass across the membrane which allows the 02/C02
exchange between air and blood, thus entering the bloodstream directly
(note that in this case the blood does not go directly through the
liver, and so there is reduced opportunity for that organ to remove or
deactivate toxics). It is also possible that the particles may adhere
to molecules of airborne toxics, and thus transfer the toxics more
efficiently to the lungs. This is apparently the situation with asbes-
tos workers who smoke cigarettes - the asbestos particles cause asbestos!
and cigarettes cause lung cancer, but both together cause the odds of
getting lung cancer to increase greatly. The theory is that the cancer-
causing substances adhere to the asbestos particles and are transferred
to the lungs more effectively because they are not exhaled, but settle
in the lungs along with the asbestos fiber. This is a grim example of
synergism - when two forces combine to become more powerful than they
would be if each acted alone.
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ECOLOGY
Ecology: Toxics Moving in the Environment
Life means recycling. Everything that is, or was, or could be a
part of any living thing is part of a grand recycling scheme. This
includes the air we breathe, the ground we walk on, the water we drink,
and our body i tself.
The entire recycling process of nature can be broken down into two
broad categories of events; growth, and decomposition. Growth is char-
acterized by substances being brought together from less concentrated
sources -such as the bringing together of parts of the soil, air and
water for the new leaves of Spring. Decomposition is just the opposite;
substances move from a concentrated, organized form into a disorganized,
more disperse form, such as the decay and 'disappearance* of the leaves
each Autumn. As toxic substances enter the environment, they also
undergo these same interactions of increase and decrease in concentra-
tion. Perhaps the best way to explain this is with an example or two.
DOT, or dichloro-Diphenyl-Trichloroethane was widely used in the
U.S. as an insecticide. tt was known to be toxic to many insects, both
beneficial and harmful, but its effects on other forms of life were
largely unknown. DDT has been very useful in the protection of many
crop plants, and has been used to fight Malaria in many parts of the
world. After many years of use, however, it was found that DDT did not
decompose into simpler compounds, but moved through nature's recycling
process virtually unchanged. DDT is an oily substance (non-polar), and
therefore it tends to become concentrated in oily areas, such as fat
tissues and river-bottom muck. It was later found that DDT is held and
accumulated in the fat tissues in animals - when the animal eats plants
or other animals with low concentrations of DDT, nearly all of the DDT
is absorbed along with the good stuff, but DDT cannot be used or ex-
creted by the body, and so the animal accumulates DDT in fat tissues.
The DDT is relatively harmless as long as it remains trapped in the fat
tissue. Problems arise, however, when the body is under stress, and
fats are used to provide emergency energy. As the fats are used, the
DDT is released tnto the bloodstream. The suddenly elevated concentra-
tions moves the DDT to all areas of the body in heavy dose, and may
cause trouble. Birds.of prey, which accumulate very high concentrations
of DDT through their position at the top of the 'Food Chain', are par-
ticularly susceptable to DDT poisoning. The DDT seems to interfere with
the formation of the egg shell, resulting in thin shells which are
easily broken (even by the extraordinarily gentle parents as they incu-
bate the egg). The production of eggs is a time of great stress for the
female, so it Is probable that her fat reserves are being released, DDT
and all, In an effort to cope with the stress. It is ironic that DOT
should be held in relatively harmless form in the fat only to be re-
leased when ft has Its most detrimental effects.
Iodine - 131 ('131 ) 's another toxic substance which may be
concentrated by the body, fodine-131 is produced in nuclear fission
(splitting of Uranium and/or Plutonium in either bombs or nuclear power
plants). Iodine of ail isotopes is absorbed by the body from food, and
18
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tends to accumulate in the Thyroid gland, where it is used in the
functioning of that gland. This small gland in the neck produces
hormones which affect nearly everything happening in the body. If the
radioactive Iodine is ingested, it will naturally become concentrated in
the Thyroid gland. As the Iodine decays, it gives off certain high
energy particles, which may cause unusual things to happen - events
which may lead to cancer of the Thyroid. Fortunately, lodine-131 decays
fairly rapidly - half of it decays every 8 days - but it is continuously
produced in power plants and other nuclear sources.
In conclusion, as long as each of us is alive and must maintain
ourselves and our children by eating food grown on the earth, and
breathing the air of the earth, we must limit ourselves to using only
chemicals which are not toxic to ourselves or other species with which
we share the earth.
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RISK ANALYSIS
Risk and Scientific Testing
Science is estimation. From the astronomers who estimate the
number of stars in the galaxy, to the zoologists who estimate how long
the average Gazelle lives, the work of a scientist is primarily forming
'educated guesses' based on a few observations. One very important
thing that a scientist must do, is to estimate how far off the true mark
the estimate is likely to be. For this reason scientific results are
customarily computed with a "confidence interval" - meaning a range of
values which is judged to have a high probability of including the
correct answer. (We could KNOW the correct answer, if we could collect
all data from al1 possible situations, but that is impractical if not
impossible.)
For example; if a chemical is tested for carcinogenic!ty, it may be
mixed with the food or air of, say, 100 white mice. Meanwhile, another
100 white mice are given the same food and air without the suspected
carcinogen. After some period of time the mice are examined for cancer.
Assume that the results are:
jt of cancers in 100 mice
Mice with chemical (test group) 6
Mice without chemical (control group) 5
What does this mean? Five mice got cancer even without the chem-
ical, but one additional mouse got cancer with the chemical. Would this
mouse have gotten cancer anyway? Or was the cancer caused by the chemical
In other words, how much confidence can we have that the one extra
cancer was caused by the exposure to the chemical? There are several
ways to decide this question.
One could use 100,000 mice, and if there were 5,000 cancers in the
control group and 6,000 In the test group, we would have to say that it
is overwhelmingly likely (though not technically proven) that the chem-
ical was causing the extra \% cancer rate. But it is very expensive to
maintain 100,000 mice, and to pay the staff to run such a large test.
The alternative Is to Increase the dose of the suspected chemical. Lets
say that we give 100 test mice ten times the former dosage - which they
would never be exposed to under "normal" conditions. This time the
results are:
# of cancers in 100 mice
Mice with lOx chemical (test group) 15
Mice without chemical (control group) 5
20
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We will probably agree that it is unlikely that all 15 in the test group
would have gotten cancer without the chemicals - but it seems that about
5 mice per 100 get cancer with or without the chemical, so we cannot
blame all 15 cancers on the carcinogen!city of the suspected chemical.
One mouse got cancer from the chemical when the dosage was one unit, and
the cancer rate increased to 10 per 100 when the concentration was
artificially increased to 10 times the former concentration.
Dose (say ppm)
1
10
Response (increase In cancer rate)
n
lot
Great. Now we may say that each unit (ppm) of
increase in cancer rate. But we really cannot
do not know any of the points in-between - and
figure of U - it is
of -since it ts such a small change.
response1 curve through these points,
bi1i t ies:
the chemical causes a 13;
be sure of that since we
what about that first
not a figure that we can really be very 'confident1
We could draw almost
for example here are
any 'dose-
three possi-
10
0:
10
GRAPH A
GRAPH B
GRAPH C
The 'x's in the above graphs represent the results that we got in our
Imaginary experiment (note that the 's' at zero does and zero response
has been added - ft Is a reasonable and necessary assumption that no
dose causes no increase). Which one of these graphs looks most likely
to you?
21
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Right off the bat Graph B looks like a sham. Why should odd doses
give higher rates than even doses? That doesn't make sense. Graph C
seems a bit less likely than A, but not quite as silly as B. The best
thing to do at this stage is to get more data - and acknowledge that
there is at least a possibility of danger in exposure to this chemical
at any level. (Note that Graphs A and C are like the Cigarette Smoking
example which was used in the introduction. Graph A represents the type
of situation with Cigarettes and lung cancer, Graph C represents cigar-
ette smoking and cancer of the esophagus.)
But this all brings us back to the question, "How much confidence
can we have that these results are accurate?" If the one extra cancer
in the first experiment was just by chance, then the lower 'x' should be
at zero, and Graph C would look like the more correct graph. If the
test group had been 100,000 mice, the extra ]% cancer rate would be
represented by an additional 1,000 cancers, and it would be hard to say
that it happened because of random chance, and so the 'x1 would be a
good 'x1; that is, we would have more confidence that it should be where
it is. Thus you can see that there is a trade-off here - the more mice
we use, the more confidence we have that our results are accurate, the
less mice we use, the less confidence we can have in the results.
This immediately brings up another trade-off: Money. How many
dollars will we spend for a given degree of confidence? How about
switching to bacteria? Bacteria can be raised by the billions, so we
can be very sure of the results - but the results are still on bacteria,
not man (or even mice). It seems less likely that chemicals should
effect man and bacteria in the same way (although results indicate that
about 90% of the chemicals which cause mutation in bacteria also cause
cancer in higher animals). Another problem with bacteria is that they
have no higher organ system and so toxins such as nerve toxins may not
be detected.
As you can see, there are many problems associated with scientific
testing, and In the ultimate analysis the tests do not tell us anything
about what is or is not true in any absolute sense. They do, however,
give us a narrow glimpse: We must use our judgment to determine the
wider meaning of the data. This judgment often requires very personal
priorities to be weighed, and so it is not optimal to have only a very
few people with technical backgrounds making these decisions of judgment
for all of society. This Is somewhat like the story of the three blind
men who touch an elephant, one touches a leg, one a tusk, and one the
long trunk - and they argue about it forever. But people are not blind,
they are able to see both the beautiful gifts and the hidden terrors of
the chemicals which we are capable of producing. Hopefully, we will be
able to tell the difference between the ones that are beneficial and
docile, like horses, and the ones which, like the wild zebra, can be
captured but nevsr tamed and should be left unexploited by the human
race.
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LAWS DEALING WITH TOXIC SUBSTANCES
Laws
A series of federal laws were created during the 1960's and 1970's
to ameliorate the effects of pollution on land, in the air and in fresh
and salt water. They also deal with the problems of identifying, con-
trolling and removing hazardous substances, in certain circumstances.
Most laws have attacked the problems in piecemeal fashion, focusing on a
few sources such as factory emissions without recognizing the inter-
relationship between air quality and water quality outside the plant as
well as the safety of the working environment inside the plant. However,
these laws are the tools which can be used to reduce the dangers which
the spread of toxic substances poses to the quality of the environment
and human health. Each law has certain strengths and weaknesses.
Regulations
Regulations to Implement the federal laws are developed by the
responsible administrative agencies, primarily the U.S. Environmental
Protection Agency. The Occupational Safety and Health Administration,
Food and Drug Administration, and Consumer Product Safety Commission
regulate employee and consumer exposure as well. Regulations spell out
in exact language which pollutants can be controlled, which are labeled
hazardous or toxic and what actions are required by the states. They
are published in the Federal Register.
Legal Definition of Toxic Substances
Legally toxic substances are materials which pose "unreasonable risk
of injury or hazard to health or the environment." 'A more comprehensive
definition is found in the New Jersey Water Pollution Control Act (P.L.
1977, Chapter 7*0. Sec. 3- r. "Toxic pollutant means those pollutants,
or combinations of pollutants, including disease causing agents, which
after discharge and upon exposure, ingestion, inhalation, or assimilation
into any organism, either directly or indirectly by ingestion through food
chains, will, on the basis of information available to the commissioner,
cause death, disease, behavioral abnormalities, cancer, genetic mutations,
physiological malfunction, including malfunctions In reproduction, or
physical deformation, in such organisms or their offspring."
Laws
At lease fifteen major federal laws have been passed since the 1961
Oil Pollution Act to define which substances will be designated toxic or
hazardous substances and how they are to be controlled.
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MAJOR LAWS CONTROLLING TOXIC SUBSTANCES
Lifted in toto from Toxic Substances Sourcebook (w/minor changes)
Steven S. Ross, Editor, Environment Information Center, Inc., New York,
New York (March 1978), p. 15.
EPA
Toxic Substances Control Act of 1976: places heavy reporting burden on
industry; EPA can demand premarket testing of some existing and all
new chemicals.
Safe Drinking Water Act of 1975: carcinogens and toxic substances in
public drinking water supplies.
Resource Conservation and Recovery Act of 1976: disposal of toxic and
other hazardous wastes in landfills; requires identification of
hazardous wastes and permits for generators, transporters, and
operators of treatment or storage facilities handling solid wastes.
Water Pollution Control Amendments of 1972 and 1977: discharges of
hazardous effluents into nation's waterways; clean-up of hazardous
spi.lls on land and in the water; control of discharges landward
.of the three-mile limit.
Marine Protection, Research and Sanctuaries Act of 1972: ocean dumping
from three to twelve miles controlled by permits.
Clean Air Act Amendments of 1970: allows EPA to set national emission
standards for hazardous air pollutants; standards now exist for
beryllium, asbestos, mercury, and vinyl chloride.
Federal Insecticide, Fungicide and Rodenticide Act of 1972: covers
sales and use of economic poisons, and foodstuff treated with such
poisons; counterpart legislation exists for enforcement by USDA
and FDA.
FDA
Federal Food, Drug and Cosmetic Act of 1906, amended in 1938 and 1962:
bars any detectable amounts of carcinogens in foods and cosmetics;
hair dyes specifically exempted.
Occupational Safety and Health Administration
Occupational Safety and Health Act of 1970: hazardous materials in
the workplace, or in products bought for use in the workplace.
Consumer Product Safety Commission
Consumer Product Safety Act of 1972: commission to enforce earlier
statutes; excludes tobacco, foods, drugs, cosmetics.
Federal Hazardous Substances Act of 1927, amended 1976: flammable,
corrosive, allergenic or toxic materials in consumer products.
-------
Flammable Fabrics Act of 1353 as amended: clothing as well as fabrics
used for other purposes in the home.
Poison Prevention Packaging: child-proof caps on containers of chemicals
drugs used in the home.
DOT
Oil Pollution Act of 1961: oil spills, chemical spills from ships.
Dangerous Cargo Act: Tank Vessel Act: Ports and Waterways Safety Act of
1972: Pipeline Safety Act: various railroad and truck transpor-
tation safety laws.
25
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Bibliography for Toxic Substances
GENERAL REFERENCES
Audubon Magazine, includes articles on environmental pollutants.
Calabrese, Edward J. Pollutants and High Risk Groups. The Biological
Basis of Increases in Human Susceptibility to Environmental and
Occupational Pollutants. Wiley-Interscience, 1978.
Center for Science in the Public Interest. The Household Pollutants
Guide. Anchor Books, 1978.
Consumer Reports, includes articles on toxic materials in consumer
products.
Consumer Research Magazine
Coulston, Frederick and F. Kerke Eds., Environmental Quality and Safety.
Vol. 5 of Global Aspects of Chemistry, Toxicology and Technology as
Applied to the Environment. Academic Press, 1976.
Council on Environmental Quality, Reports on Environmental Quality
Washington, D. C. 1969 and on. Annual report of the Council on
Environmental Quality.
Dinman, B.D., Non-concept of No-Threshold: Chemicals in the Environment.
Science 175= 495-97-
Environment magazine, popular accounts of environmental problems.
Environmental Science and Technology
Fuller, John G., The Poison That Fell From The Sky. Random House.
New York, 1977. Popular account of industrial accident in Italy.
Gardener and Cook, Chemical Synonyms and Trade Names, 7th Edition
CRC Press, 1971-
Gosselin, Robert E. et al. Clinical Toxicology of Commercial Products.
4th Edition, Williams and Wilktns, 1976.
Prevention, popularly written accounts of health effects of substances.
Sax, N. Irving, Dangerous Properties of Industrial Materials, 4th Ed.
Van Nostrand Reinhold Co. New York, 1975-
Science, weekly magazine includes reports of original scientific work
and articles on matters of science related to economics and politics
Series on Toxic Substances: Toxic Substances Legislation: How
Well Are Laws Being Implemented? Science Volume 201: 1198. Sept.
29, 1978.
Chemical Carcinogens: How Dangerous are Low Doses? Science Volume
202: 37, Oct. 6, 1978.
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BACKGROUND MATERIAL: BIOLOGY, ECOLOGY, PHYSIOLOGY, TOXICOLOGY, TESTING
Ariens, E.J., A.M. Simonis, and J. Offermeier,
Introduction to General Toxicology, Academic Press, N.Y. 1976
Discussion of cellular mechanisms, exposure, defense mechanisms,
interaction of substances, metabolism of toxic substances.
Bell, George H., Textbook of Physiology and Biochemistry. 9th Ed.
Churchill Livingstone, Medical Division of Longman Inc. 1976
Longman, Inc. 19 W. M»th St., N.Y.C. 10036, $25- Well written
textbook for undergraduate and postgraduate students.
Berry, James W. et al, Chemical Villains, A Biology of Pollution.
C.B. Mosby Co., St. Louis, 1971* $9-95. Basic background information
on ecology, biology and the effects and sources of familiar toxic
materials.
Casarett, Louis J. and John Doul1, Eds. Toxicology, the Basic Science of
Poisons. MacMlllan Publishing Co. New York, 1975- A graduate
level text on toxicology.
Cole, G.A., Limnology, C.V. Mosby, St. Louis, 1975
Test on the science of streams, lakes and ponds.
Cudmore, L. Larison, The Center of Life: A Natural History of the Cell.
(Quadrangle Press, N.Y. Times, 1977 $8.95. For the general reader,
well written In a bright style.
DeWitt, William, Biology of the Cell: An Evolutionary Approach.
W.B. Saunders, 1977, $13-95- Basic test on biology.
Hunter, W.J. and J.G. Smeets, Eds. The Evaluation of Toxicological Data
for the Protection of Public Health.
Oxford, Pergamon Press, 1977-
Odum, Eugene, Fundamentals of Ecology, W. B. Saunders 1971
The classic test on ecology.
Pachter, H.M. Paracelsus: Magic into Science, Collier Books, N.Y l°6l.
Paracelsus (H93-15M) is considered the founder of toxicology. He
promoted the concept of the toxic agent as a chemical entity and
articulated the dose/response concept.
Paget, G. E. Ed. Methods in Toxicology. F.A. Davis Co., Philadelphia
Blackwell Scientific Publications 1970. Explanation of early
approaches to toxicology including LD .
Rothwell, Norman V. Human Genetics, Prentice-Hall, 1977, $1^.50
Accurate, up-to-date, for college students, non-science majors.
Tardiff, Robert G. tn VJtro Methods of Toxic Evaluation. Ann. Rev.
Pharmacology and Toxicology 18:357'67 1978.
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Waldbott, George, Health Effects of Environmental Pollutants, 2nd Ed.
C.V. Mosby, 1979, $13.50. Description of how various chemical
pollutants can affect the human body. Non-technical style with
case histories, college level.
CHEMICAL CARCINOGENS AND MUTAGENS
American Cancer Society, Cancer Facts and Figures
Ames, Bruce, et al., Carcinogens are Mutagens : A Simple Test System
Combining Liver Homogenates for Activation and Bacterial for
Detection. Proc. Nat. Academy of Sciences 70: 2281-2285, 1973-
Auerbach, Charlotte, Mutation Research. Problems, Results and Per-
spectives, Halsted Press, 1976.
Busch, Harris, Ed. The Molecular Biology of Cancer, Academic Press,
New York,
Council on Environmental Quality: Carcinogens in the Environment.
Reprint from the 6th Annual Report, Dec. 1975. Available from
Supt. of Documents, U.S. Govt. Printing Office, Washington, D.C.
20*»02, $.75, Stock No. OM -01 1-00030-1 .
Epstein, S.S., Environmental Determinants of Human Cancer,
Cancer Research 3^:2^25,
Epstein, S.S., The Political and Economic Basis of Cancer,
Technology Review, 78:1, 1976.
Fraumeni, Joseph F. Ed., Persons at High Risk of Cancer. An approach
to Cancer Etiology and Control. Proceedings of a Conference, Key
Biscayne, 197^. Academic Press, London, 1975.
Hiatt, Watson and Winsten, Eds. Origins of Human Cancer. Cold Spring
Harbor Conferences on Cell Proliferation, k Vols. Cold Spring
Harbor Laboratories, 1977-
Hollaender, Alexander, Ed. Chemical Mutagens - Principles and Methods
for their Detection. Plenum Press, New York, k VoTs. 1971 - 1975-
I ARC: Evaluation of Carcinogenic Risk of Chemicals to Man. Vols 1-16.
Kraybill, H.F., and M.A. , Mehlman Eds., Environmental Cancer, Advances
in Modern Toxicology, Vol. Ill, Halsted Press, 1977.
National Academy of Sciences Magazine, Summer 1978.
Saffiotti, U. and Wagoner J.K. Eds. Occupational Carcinogenesi s , Annals
of N.Y. Academy of Science Vo. 271, 1976.
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PESTICIDES: INSECTICIDES, HERBICIDES, FUNGICIDES
Audus, L.J. Ed., Herbicides: Physiology, Biochemistry, Ecology, 2nd Ed.
Academic Press, London/New York, 1976, 2 volumes.
Gunn, D.L. and J.G.R. Stevens, Eds., Pesticides and Human Welfare.
Oxford University Press, 1976, $A paper.
Haque, Rizwanul and V.H. Freed, Environmental Dynamics of Pesticides.
Vol. 6 in Environmental Science Research, Plenum, N.Y., 1975.
Hayes, Wayland J., Toxicology of Pesticides. Williams and Workings Co.
1977-
Pesticides Monitoring Journal. Federal Working Group on Pest Manage-
ment. Group responsible to the Council on Environmental Quality.
Plimmer, Jack R. et al. Editors, Pesticide Chemistry in the Twentieth
Century. American Chemical Society, 1977- Review papers, dis-
cussions of recognition of risks, resistance to pesticides.
U.S.E.P.A. Pesticide Safety Tips (A107)
U.S.E.P.A. Safe Pesticide Use Around the Home, Washington, D.C.
Sept.
Upholt, W., Pest Control Technology and the E.P.A.: What is Responsible
Regulations? Environmental Management, Vol. 1 pp. 484-^89, 1978.
Watson, David L. and A.W. Brown, Editors, Pesticide Management and
Insecticide Resistance. Academic Press, 1977 (1978?).
AIR POLLUTION
Aharonson, E.F. et al., Editors. Air Pollution and the Lung. Wiley,
New York, 1976.
American Lung Association: Air Pollution Primer.
Conservation Foundation: Citizen's Guide to Clean Air. A Manual for
Citizen Action. Washington, D. C.
Cote, W.A. et al. A Study of Indoor Air Quality. E.P.A. Research,
Triangle Park, N. Carolina, Sept. 197*».
Finkel, A. J. and W.C. Duel, Editors, Clinical Implications of Air
Pollution Research. Proceedings of A.M.A. Air Pollution Medical
Research Conference, Dec. 5~6, 197*». Publishing Sciences Group,
Inc. Acton, Mass. 1976.
Friedlander, Smoke, Dust and Haze, Wiley, 1977-
Good, W.O. et al. Sputum Cytology Among Frequent Users of Pressurized
Spray Cans. Cancer Research 35: 316-21. 1975.
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Hogan, Barbara, Aerosol Sprays. Center for Science in the Public
Interest. 1976.
Mansfield, T.A. Ed., Effects of Air Pollutants on Plants. Society for
Experimental Biology Seminar Series. 1976, Cambridge Univ. Press.
Mitre Corp. Scoring of Organic Air Pollutants: Chemistry, Production
and Toxicity of Selected Synthetic Organic Chemicals. McLean, Va.
Sept. 1976.
National Academy of Sciences, Committee on Medical and Biological
Effects of Environmental Pollutants: Ozone and other Photochemical
Oxidants. Washington, D.C. 1977.
National Academy of Sciences. Physiological and Toxicological Aspects
of Combustion Products.
Stern, Arthur C. Editor: Air Pollution, 3rd Edition. 5 Volumes.
1976 Vol I Air Pollutants, Their Transformation and Transport.
1977 Vol II The Effects of Air Pollution
1976 Vol III Measuring, Monitoring & Surveillance of Air Poll.
1977 Vol IV Engineering Control of Air Pollution
1977 Vol V Management
U.S. Environmental Protection Agency. Air Quality Criteria for Lead.
Dec. 1977 E.P.A. 600/8-77-017-
Wade, W.A. et al. A Study of Indoor Air Quality. Journal of the Air
Pollution Control Assoc. Sept. 1975, pp. 933'39-
ECONOMIC ANO LEGAL ASPECTS:
Ayres, Robert U. Resources, Environment and Economics.
Applications of the Materials/Energy Balance Principle. Wiley-
Intersclence, 1978.
Chemical Week. McGraw Hill, 1221 Ave. of the Americas, N.Y.C. 10020
Weekly magazine for Industry news from business viewpoint.
Chemical and Engineering News.
Magazine for technical information related to economics of the
chemical industry.
Commoner, Barry. The Closing Circle, Nature, Man and Technology.
1971, Alfred A. Knopf, Inc. 1972, Bantam Books Edition.
Down, C. G. and J. Stocks, Environmental Impact of Mining. Halsted
Press, 1977.
Dales, J.H. Pollution, Property and Price. University of Toronto
Press,Toronto, Canada, 1972.
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Ecology Law Quarterly, Special Issue: Hazardous Substances in the
Environment, Law and Policy. Vol. 7, No. 2, 1978. Available from
School of Law, Boalt Hall, Univ. of California, Berkeley, Calif-
ornia, 9^720, $5.
Industrial Wastes, Scranton Gillette Communications, Inc.
k}k S. Wabash Ave., Chacago, 111., 60605- Magazine for industrial
waste processing industry.
Resources for the Future, (1755 Mass. Ave. N.W., Wash. D.C., 20036)
Current Issues in U. S. Environmental Policy. Johns Hopkins Univ.
Press, $A.95, available from above address.
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