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#249 - Dioxin Dangers -- What's Going On, 03-Sep-1991

We urge our readers to attend the First Citizens' Conference on Dioxin
September 21-22, 1991, at the Omni-Europa Hotel in Chapel Hill, North
Carolina. For more information phone Ellen and Paul Connett in Canton,
NY: (315) 379-9200. The conference will discuss the latest scientific
information on dioxin, fraud and manipulation in dioxin studies, and
solutions to the dioxin problem offered by citizens.

The recent flap in the press over dioxin can all be traced back to a
single government scientist who announced in April that he believes
dioxin is less able to cause cancer in humans, and is therefore less
dangerous, than he believed 10 years ago. In late April, Vernon N.
Houk, a 62-year-old government worker, was keynote speaker at a
University of Missouri conference sponsored by Syntex, a company that
was being sued in a Missouri court by the family of a truck driver who
had died of cancer and who had worked for years in a truck terminal
that was contaminated with dioxin. Syntex faces another 350 dioxin
lawsuits from individuals who lived at Times Beach, Missouri--a town
the U.S. government bought out when they found it was heavily
contaminated with dioxin, 10 years ago. During his speech in April, Dr.
Houk dropped a bombshell: he said he believed he himself had made a
mistake 10 years ago when he urged the federal government to evacuate
2200 residents from Times Beach. In August, the NEW YORK TIMES turned
Dr. Houk's reassessment into two front-page stories and an editorial,
the main message of which was, "Many scientists now believe dioxin
isn't as bad as we thought." At least 26 other newspapers in the U.S.
and Canada jumped on the bandwagon.

As the summer wore on, Dr. Houk himself went even further. In August he
was quoted in the SEATTLE (Washington) TIMES (August 18, pg. B3) saying
he believed the pulp and paper industry in the northwestern U.S. "has
reduced dioxin levels enough to protect public health." He said this
was his personal view, not a government opinion. As we saw last week
(RHWN #248), the paper industry is facing so many dioxin lawsuits that
it is now being compared to the asbestos industry. In a story devoted
to Dr. Houk himself, the NEW YORK TIMES noted that he is now being
praised and acclaimed (the TIMES said "lionized") by industrial
companies that produce dioxin as a waste product, because they say he
has put an end to the "dioxin scare."

Dr. Houk's views on the dangers of dioxin reflect the narrow public
health perspectives of the federal government. Standards for exposure
to a chemical are generally based on the chemical's ability to cause
cancer, and not on its ability to cause other health problems. On this
basis, Dr. Houk justifies his change of heart: "If [dioxin's] a
carcinogen, it's a very weak carcinogen and Federal policy needs to
reflect that," Dr. Houk says.

In actual fact there is much new scientific evidence indicating that
dioxin is more dangerous than anyone knew 10 years ago. Recent evidence
(summarized in a long article in the NEW YORK TIMES May 15, 1991 [pg.
C4], and in CHEMICAL & ENGINEERING NEWS August 12, 1991 [pgs. 7-14])
reveals that dioxin has many toxic effects on wildlife and humans
besides its ability to cause cancer. In one species of animal or
another, dioxin causes wasting syndrome [progressive weight loss
leading to death]; atrophy of the thymus (a blood-forming organ
important in the immune system); atrophy of the spleen (another blood-
forming organ important in the immune system); atrophy of the
testicles; enlargement, deterioration and death of liver tissue;
hyperplasia (excessive cell growth) in the urinary tract and bile
ducts; birth defects; and suppression of the immune system. In
addition, its ability to cause cancer in laboratory animals, wildlife
and humans is now a matter of record (see RHWN #219.)

The present understanding of dioxin is that it functions like a steroid
hormone. Steroid hormones are powerful chemicals that enter cells, bind
to a "receptor" (a protein), form a "complex" that then attaches to the
cell's chromosomes where it directly encounters the genetic material,
turning on and off chemical switches that may then affect distant parts
of the body in various important ways. It is not unusual for very small
amounts of a steroid hormone to have major effects on the body.

In animal studies, dioxin is still the most potent poison ever seen.
For example, it kills hamsters at one 64-thousandth of the fatal dose
of sodium cyanide. The hamsters die of "wasting syndrome"--they lose
weight and die. In rainbow trout, northern pike, and salmon, one-tenth
of a part per trillion of dioxin in water causes growth retardation of
young fish. The U.S. Fish and Wildlife Service calls dioxin "the most
toxic synthetic compound ever tested under laboratory conditions."[1]
No new evidence has changed any of this. Back when Dr. Houk was
recommending that people be evacuated from Times Beach, in 1981, the
danger did not seem remote or theoretical. Seventy-five horses in the
town had died. Dogs, rodents, chickens, cats and birds had died. No new
evidence has been found in the past 10 years to change anyone's
estimate of dioxin's toxicity to these species.

In rhesus monkeys, as little as 25 parts per trillion in the diet
causes increased passivity and measurable reductions in the ability to

"With laboratory animals, it seemed as if dioxin caused just about any
effect you can think of," says Dr. Steven Safe, a toxicologist at Texas
A&M University. "You name it, it did it, and at extremely low doses,"
he says. Dr. Safe says the mystery of dioxin has largely been solved by
confirmation that TCDD [dioxin] and other toxic agents interact
directly with genetic material [the chromosomes that, taken together,
comprise the DNA molecule], the way hormones do. It is not unusual for
a hormone to have different effects and different potencies in
different species of animals. This does not make dioxin any less toxic-
-it merely makes it better-understood.

CHEMICAL & ENGINEERING NEWS says, "One of the most significant
realizations of the past few years is that TCDD [dioxin] cannot be
considered by itself... that there are a number of dioxin-like
compounds that can all have toxic effects." Dioxins, dibenzofurans,
PCBs, and some halogenated naphthalenes all mimic hormones; therefore
scientists now believe they can all cause the range of toxic effects
attributed to dioxin. This is not good news for anyone because dioxin
alone may account for 7 ppt [parts per trillion] in the blood of
average Americans but when these related compounds are taken into
consideration, the average American may be carrying 100 ppt of dioxin
equivalents in his or her blood stream. The meaning of these levels of
contamination will become clearer in the next few years.

Even now, far-reaching effects in fish and birds in the Great Lakes are
observable at 35 to 65 ppt. Philip M. Cook at the U.S. Environmental
Protection Agency laboratory in Duluth, MN, says he believes Great
Lakes fish are failing to reproduce already because of the dioxin
burden they carry.

Researchers observing wildlife in the Great Lakes are seeing
hermaphroditic offspring of birds--for example, male birds with
partially developed female sex organs. They are seeing female-female
bonding behavior. These potent dioxin-family toxins seem to act like,
or interfere with, normal sex hormones like estrogen, producing
"chemically castrated" males, and sexually-confused females.

Linda S. Birnbaum, director of the Environmental Toxicology Division of
the EPA's Environmental Health Effects Research Laboratory has overall
responsibility for the EPA's year-long reassessment of dioxin's
toxicity (see RHWN #248). Unlike Vernon Houk, for whom "the issue is
mostly decided" already (says CHEMICAL & ENGINEERING NEWS), Dr.
Birnbaum believes when all the evidence has been evaulated, EPA may not
change its regulatory number for dioxin much. The number was initially
established because of a great fear of dioxin as a carcinogen. Now a
whole new set of toxic properties of dioxin, and dioxin-like chemicals,
have become apparent, even as the carcinogenicity question has assumed
less importance.

--Peter Montague


REVIEWS REPORT NO. 8]. Laurel, Maryland: U.S. Department of the
Interior, Fish and Wildlife Service, Patuxent Wildlife Research Center,
May, 1986.

[2] R. Bowman and others. "Behavioral Effects in Monkeys Exposed to
2,3,7,8-TCDD Transmitted Maternally During Gestation and for Four
Months of Nursing," CHEMOSPHERE Vol. 18 (1989), pg. 235.

Descriptor terms: dioxin; vernon houk; mo; syntex co; times beach, mo;
pulp and paper industry; wildlife; cancer; immune system; birth
defects; birds; fish; endocrine disrupters; health; epa; dioxin

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