Dear All,
Bapak/Ibu sekalian, maaf sekali lagi artikel bahasa inggris tentang dioxin dan
kesehatan, semoga bermanfaat.
Maaf bagi Bapak/Ibu yang tidak berkenan
Best Regard,
Ishmael+Indang+Iwan
RACHEL'S ENVIRONMENT & HEALTH WEEKLY #463, October 12, 1995
News and resources for environmental justice.
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: [EMAIL PROTECTED]
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
===============
[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.
[2] Pat Costner, PVC: A PRIMARY CONTRIBUTOR TO THE U.S. DIOXIN BURDEN
(Washington, D.C.: Greenpeace, February, 1995); $15.00; available from Sanjay
Mishra at Greenpeace: (202) 319-2444.
[3] Copies of the Science Advisory Board's dioxin critique are available, while
supplies last, by phoning (202) 260-8414.
[4] Michael J. DeVito and others, "Comparisons of Estimated Human Body Burdens
of Dioxinlike Chemicals and TCDD Body Burdens in Experimentally Exposed
Animals," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, No. 9 (September, 1995),
pgs. 820-831.
[5] Raymond R. Suskind, PROGRESS REPORT -PATIENTS FROM MONSANTO CHEMICAL
COMPANY, NITRO, WEST VIRGINIA, APRIL, 1950 (Cincinnati, Ohio: Kettering
Laboratory, April, 1950), pg. 9.
[6] S.L. Schantz and others, "Learning in monkeys exposed perinatally to
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)." NEUROTOXICOLOGY AND TERATOLOGY Vol.
11 (1989), pgs. 13-19. And see: R. Bowman and others, "Behavioral Effects in
Monkeys Exposed to 2,3,7,8-TCDD Transmitted Maternally During Gestation and
During Four Months of Nursing." CHEMOSPHERE Vol. 18 (1989), pgs. 235-242.
[7] Grace M. Egeland and others, "Total Serum Testosterone and Gonadotropins in
Workers Exposed to Dioxin," AMERICAN JOURNAL OF EPIDEMIOLOGY Vol. 139 (1994),
pgs. 272-281.
[8] Reuters reported October 6 on a new 20-year study of Air Force veterans
exposed to Agent Orange. Reuters said the new study shows that dioxin-exposed
vets have an increased incidence of diabetes and heart disease. We believe the
new study is available from Donna Tinsley at the Air Force; phone (202)
767-4587. Thanks to Pat Costner of Greenpeace for this intelligence.
Kunjungi:
http://www.balita-anda.indoglobal.com
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