=======================Electronic Edition========================
RACHEL’S ENVIRONMENT & HEALTH WEEKLY #463
—October 12, 1995—
News and resources for environmental justice.
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DIOXIN AND HEALTH
The word “dioxin” stands for a group of chemicals that occurs
rarely, if ever, in nature. A very large proportion of dioxin
comes from human sources. Dioxin began accumulating in the
environment around 1900 when the founder of Dow Chemical (in
Midland, Michigan) invented a way to split table salt into sodium
atoms and chlorine atoms, thus making large quantities of “free
chlorine” available for the first time. [1](Dow’s chlorine is
“free” in the sense of “chemically unattached,” not free in the
sense of “without cost.”) Initially, Dow considered free
chlorine a useless and dangerous waste. But soon a way was found
to turn this waste into a useful product, attaching chlorine
atoms onto petroleum hydrocarbons and thus creating, during the
1930s and 1940s, a vast array of “chlorinated hydrocarbons.”
These new chemicals, in turn, gave rise to many of today’s
pesticides, solvents, plastics, and so forth. Unfortunately,
when these chlorinated hydrocarbons are processed in a chemical
plant, or are burned in an incinerator, they release an unwanted
byproduct –dioxin –the most toxic family of chemicals ever
studied.
Dioxin is released by paper mills, by metal smelters, by many
chemical plants, by many pesticide factories, and by all
incinerators. According to Greenpeace chemist Pat Costner, the
biggest source of dioxin discharges into the environment is
factories that make the popular plastic, PVC (polyvinyl
chloride). [2] Industry and EPA (U.S. Environmental Protection
Agency) have known much of the bad news about dioxin since at
least the late 1970s, but have done little or nothing about it.
In 1991, the paper industry and the Chlorine Council (a trade
group) pressured EPA to relax the few dioxin standards that EPA
had set at the time; in response, EPA has spent the last 4 years
re-examining the toxicity of dioxin, in preparation for deciding
what to do about it. (See RHWN #269, #270,
#275.) EPA released
a draft of its 9-volume “dioxin reassessment” last year (see RHWN #390 and #391). Yesterday, EPA’s Science Advisory Board released
its own critique of the 9-volume “dioxin reassessment.” [3]
So-called “conservatives” in Congress have attacked Chapter 9 of
EPA’s dioxin reassessment –the chapter that contains most of the
chillingly bad news about dioxin. We reported in REHW #457 that
Congress was preparing to pillory EPA scientists in a public
hearing; that hearing has been delayed, and perhaps has been
scrapped completely. “Conservatives” in Congress complain that
Chapter 9 has not been adequately “peer reviewed.”
Last month the main authors of EPA’s Chapter 9 published –in a
peer-reviewed journal –their own conclusions about the toxicity
of dioxin. [4]
The basic message from these senior EPA scientists is that dioxin
is toxic to humans in surprisingly many ways, and that the
general public is not adequately protected from ill effects by a
traditional “margin of safety.” Public health policy usually
aims to keep the public’s exposure to poisons at least 100 times
below levels known to harm humans or animals. As we will see,
this new report from EPA shows that U.S. adults are already
carrying around an average dioxin burden in their bodies that is
remarkably close to the levels known to cause illness in humans
or animals.
We want to note at the outset that all of the results reported
here were taken from peer-reviewed literature and were
statistically significant. All of the following information is
taken from the new EPA study. [4]
EPA’S LATEST FINDINGS: EPA says the average U.S. citizen has no
particular exposure to dioxin besides what is routinely eaten in
food –mainly in red meat, fish, and dairy products. This
routine dietary exposure has produced an average body burden that
is estimated to be 13 nanograms of dioxin per kilogram of body
weight (ng/kg). (A nanogram is a billionth of a gram; a gram is
1/28th of an ounce. A kilogram is about 2.2 pounds.) Ng/kg is
equivalent to parts per trillion. So 13 ng/kg seems tiny –and
as an absolute quantity it is. But compared to the amount that
causes havoc in dioxin-exposed animals and humans, 13 ng/kg
qualifies as a major public health problem, in our opinion. (EPA
estimates that 5% of Americans –some 12.5 million people –have
body burdens twice the average.) Here are some effects of
dioxin, as reported by EPA: [4]
CHLORACNE: Chloracne was the first disease associated with
exposure to dioxin, first described in 1897. Chloracne appeared
as an occupational problem in the 1930s among pesticide workers,
and among workers who manufactured industrial chemicals called
PCBs [polychlorinated biphenyls]. However, dioxin was not
identified as the cause of chloracne until about 1960. (Dioxin
was an unwanted contaminant of the pesticides and PCBs.)
Chloracne produces skin eruptions, cysts and ‘pustules’ –like a
very bad case of teenage acne, except that the sores can occur
all over the body and in serious cases can last for many years.
To grasp the nature of a bad case of chloracne, we can recall Dr.
Raymond Suskind’s description of one of his patients, a white man
who got chloracne from dioxin exposure in a Monsanto chemical
plant in West Virginia in 1949: “… he has given up all social
and athletic functions and remained in his house, according to
his own description, for months on end. Several times he has
been mistaken for a Negro and forced to conform with the racial
segregation customs of the area. This has happened on buses or in
the theatres [sic],” Suskind wrote. [5]
In laboratory animals, chloracne occurs at body burdens as low as
23 ng/kg and as high as 13,900 ng/kg; in humans, chloracne has
occurred at body burdens as low as 96 ng/kg and as high as 3000
ng/kg. This means that some humans get chloracne when their
dioxin body burden is only 7 times as high as the body burden of
the average person in the U.S. today. In other words, there is
not even a factor of 10 separating the average person from the
possibility of chloracne. In fact, the EPA study cites examples
of humans getting chloracne with body burdens only 3 times as
high as the U.S. average.
CANCER: There have been 5 peer-reviewed studies showing cancer in
humans exposed to dioxin. The exposures occurred through
accidents or through routine activities at work. These studies
of humans show that, for some human populations, the danger of
cancer begins to rise noticeably when the dioxin body burden
reaches 109 ng/kg. This means that a cancer effect in humans is
evident when the dioxin body burden reaches a point 8 times as
high as the average dioxin body burden in the U.S. public.
Again, there is not a factor of even 10 separating the average
American from the possibility of cancer from dioxin.
BEHAVIORAL EFFECTS & LEARNING DISORDERS: Laboratory experiments
on monkeys (marmosets) reveal learning disabilities in young
monkeys with a dioxin body burden as low as 42 ng/kg. [6] Thus
learning disorders are evident in monkeys who have a dioxin body
burden only 3.2 times as high as that of the average American.
Again, there is not a factor of even 10 separating the average
U.S. resident from the possibility of a dioxin effect on the
central nervous system.
DECREASED MALE SEX HORMONE: Researchers at the National Institute
of Occupational Safety and Health (NIOSH) found reduced levels of
testosterone –male sex hormone –circulating in the blood of
dioxin-exposed male workers. [7] Other sex hormone levels in
these men were affected as well. If we can assume that dioxin
exposure caused the diminished testosterone levels, then some
humans are 280 times as sensitive as rats are, from the viewpoint
of testosterone. What seems most important is that these
dioxin-exposed workers had body burdens only 1.3 times the dioxin
body burden of the U.S. population. Thus there is not even close
to a factor of 10 separating the average U.S. male from the
testosterone effects seen in dioxin-exposed workers. The
reduction in testosterone levels was statistically significant,
but the reduction was small and the measured levels still
remained within the range that is considered normal.
DIABETES: In two studies, an increased incidence of diabetes has
been reported in dioxin-exposed Vietnam veterans; a third study
that reaches similar conclusions was reportedly released last
week by the U.S. Air Force. [8] The body burdens that seem to
produce an increase in diabetes range from 99 to 140 ng/kg. Thus
the average American, with a body burden of 13 ng/kg, is a factor
of 8 below the lowest level thought to create a diabetes hazard.
Once again, there is not even a factor of 10 separating the
general public from the levels though to cause health problems in
dioxin-exposed people.
IMMUNE SYSTEM TOXICITY: In monkeys (marmosets), changes in white
blood cells associated with the immune system can be measured at
dioxin levels of 10 ng/kg –25% below the level already found in
average Americans. Mice with body burdens of 10 ng/kg –25%
below the amount already found in you and me –display an
increased susceptibility to infections by viruses, presumably
because their immune system has been damaged.
SPERM LOSS AND ENDOMETRIOSIS. Female rhesus monkeys with body
burdens only 5 times as high as the U.S. average have a
measurable increase in the painful, debilitating disease of the
uterus, called endometriosis. Endometriosis is increasing in U.S.
women. (RHWN #364, #377.) Male
offspring of rats with a body
burden only 5 times as high as the U.S. average have diminished
sperm production. During the last 50 years, sperm production of
men through the industrialized world has dropped 50%. (RHWN #343,
#432.)
CONCLUSION: We have only scratched the surface of the bad news
that has accumulated about dioxin. It is an astonishingly
versatile and potent poison. EPA, and the corporations that
release dioxin into the environment, have waffled and fudged for
20 years or more. The answer to this burgeoning public health
problem is clear, if not easy: over the next 20 years, we must
ban chlorine as an industrial feed stock and thus cut off the
source of all dioxins. What other choice do we have?
                
                
                
                
    
–Peter Montague
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[1] Jack Weinberg, editor, DOW BRAND DIOXIN (Washington, D.C.:
Greenpeace, September, 1995); 34 pages, $15.00, from Sanjay
Mishra at Greenpeace: (202) 319-2444.
Descriptor terms: dioxin; chlorine; dow chemical; epa; studies;
pesticides; solvents; metal smelters; paper mills; pulp mills;
pvc; polyvinyl chloride; pcbs; science advisory board; sab; food
safety; diet; meat; milk; dairy products; fish; chloracne;
cancer; learning disorders; central nervous system; testosterone;
male sex hormones; occupational safety and health; diabetes;
ranch hand study; vietnam veterans; immune system toxicity;
viruses; sperm loss; endometriosis; greenpeace; pat costner;