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 What is dioxin?

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عدد المساهمات : 120
تاريخ التسجيل : 16/01/2012
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مُساهمةموضوع: What is dioxin?   الإثنين أبريل 30, 2012 3:46 am

Dioxins and furans are some of the most toxic chemicals known to science. A draft report released for public comment in September 1994 by the US Environmental Protection Agency clearly describes dioxin as a serious public health threat. The public health impact of dioxin may rival the impact that DDT had on public health in the 1960's. According to the EPA report, not only does there appear to be no "safe" level of exposure to dioxin, but levels of dioxin and dioxin-like chemicals have been found in the general US population that are "at or near levels associated with adverse health effects."
Dioxin is a general term that describes a group of hundreds of chemicals that are highly persistent in the environment. The most toxic compound is 2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD. The toxicity of other dioxins and chemicals like PCBs that act like dioxin are measured in relation to TCDD. Dioxin is formed as an unintentional by-product of many industrial processes involving chlorine such as waste incineration, chemical and pesticide manufacturing and pulp and paper bleaching. Dioxin was the primary toxic component of Agent Orange, was found at Love Canal in Niagara Falls, NY and was the basis for evacuations at Times Beach, MO and Seveso, Italy.
Dioxin is formed by burning chlorine-based chemical compounds with hydrocarbons. The major source of dioxin in the environment comes from waste-burning incinerators of various sorts and also from backyard burn-barrels. Dioxin pollution is also affiliated with paper mills which use chlorine bleaching in their process and with the production of Polyvinyl Chloride (PVC) plastics and with the production of certain chlorinated chemicals (like many pesticides).
Does dioxin cause cancer?
Yes. The EPA report confirmed that dioxin is a cancer hazard to people. In 1997, the International Agency for Research on Cancer (IARC) -- part of the World Health Organization -- published their research into dioxins and furans and announced on February 14, 1997, that the most potent dioxin, 2,3,7,8-TCDD, is a now considered a Group 1 carcinogen, meaning a "known human carcinogen."
Also, in January 2001, the U.S. National Toxicology Program upgraded 2,3,7,8-TCDD from "Reasonably Anticipated to be a Human Carcinogen" to "Known to be a Human Carcinogen." See their reports on dioxins and furans from their most recent 11th Report on Carcinogens. Finally, a 2003 re-analysis of the cancer risk from dioxin reaffirmed that there is no known "safe dose" or "threshold" below which dioxin will not cause cancer.
A July 2002 study shows dioxin to be related to increased incidence of breast cancer.
What other health problems are linked to dioxin exposure?
In addition to cancer, exposure to dioxin can also cause severe reproductive and developmental problems (at levels 100 times lower than those associated with its cancer causing effects). Dioxin is well-known for its ability to damage the immune system and interfere with hormonal systems.
Dioxin exposure has been linked to birth defects, inability to maintain pregnancy, decreased fertility, reduced sperm counts, endometriosis, diabetes, learning disabilities, immune system suppression, lung problems, skin disorders, lowered testosterone levels and much more. For an detailed list of health problems related to dioxin, read the People's Report on Dioxin.
How are we exposed to dioxin?
The major sources of dioxin are in our diet. Since dioxin is fat-soluble, it bioaccumulates, climbing up the food chain. A North American eating a typical North American diet will receive 93% of their dioxin exposure from meat and dairy products (23% is from milk and dairy alone; the other large sources of exposure are beef, fish, pork, poultry and eggs). In fish, these toxins bioaccumulate up the food chain so that dioxin levels in fish are 100,000 times that of the surrounding environment. The best way to avoid dioxin exposure is to reduce or eliminate your consumption of meat and dairy products by adopting a vegan diet. According to a May 2001 study of dioxin in foods, "The category with the lowest [dioxin] level was a simulated vegan diet, with 0.09 ppt.... Blood dioxin levels in pure vegans have also been found to be very low in comparison with the general population, indicating a lower contribution of these foods to human dioxin body burden."
In EPA's dioxin report, they refer to dioxin as hydrophobic (water-fearing) and lipophilic (fat-loving). This means that dioxin, when it settles on water bodies, will rapidly accumulate in fish rather than remain in the water. The same goes for other wildlife. Dioxin works its way to the top of the food chain.
Men have no ways to get rid of dioxin other than letting it break down according to its chemical half-lives. Women, on the other hand, have two ways which it can exit their bodies:
• It crosses the placenta... into the growing infant;
• It is present in the fatty breast milk, which is also a route of exposure which doses the infant, making breast-feeding for non-vegan/vegetarian mothers quite hazardous.
Where does dioxin come from?
According to EPA, only 50% of dioxin sources are known. Of these, 95% comes from combustion processes. Garbage and medical waste incinerators are the largest identified sources.
Incinerators -- 95% of 50%
Dioxin is generated by the chlorine content in the waste stream burned in medical and garbage incinerators. Chlorine is present in various plastics, mostly PVCs. When these plastics are burned, chlorine is released, and quickly reacts with available phenol compounds to form dioxin. The phenol compounds are present in wood and paper products. Dioxins are released to the air, end up in the bottom ash, and in the fly ash captured by pollution control equipment.
When chemicals such as PCBs, chlorinated benzenes and chlorinated phenols are burned in hazardous waste incinerators, chlorine combines with available phenol compounds to form dioxin.
The Missing 50%
Although EPA identified chemical manufacturing/ processing and industrial/municipal processes as major sources of dioxin emissions, they had no data to measure how much dioxin is released from these sources. EPA acknowledged that the "agency lacks sufficient information about emissions from known sources" (emphasis added) and has asked industry to "call-in" with information on their dioxin emissions. Forest fires and vehicle exhaust are on the list, but known dioxin sources such as Dow Chemical in Midland, Michigan, Vertac in Jacksonville, Arkansas, and Monsanto in St. Louis, Missouri are omitted.
The Missing Chemical Industry
A major but unmeasured source of dioxin is the chemical industry -- in processes that use chlorine in the production of pesticides, pharmaceuticals, cosmetics, detergents, solvents, and dyes. Herbicides such as agent orange and 2,4-D are made by adding chlorine to phenoxy compounds. Dioxin is formed as a by-product and ends up in the formulated end-product, such as the herbicide Agent Orange or pure PVC polymer, as well as in the process waste streams.
The Unmeasured Pulp and Paper Industry
Another major source of dioxin emissions are pulp and paper mills. Dioxin is formed in the pulp and paper industry when chlorine or chlorine dioxide is used to bleach pulp and paper. Naturally occurring phenol compounds found in wood pulp react with chlorine to form dioxin. This results in dioxin in paper products, paper mill sludge, and in the wastes from these plants.
How Are People Exposed to Dioxin?
Dioxin, like DDT, does not break down easily in the environment. Instead, it bioaccumulates. This means that the body accumulates any dioxin to which you are exposed. Over time, continual low level exposures will "build up" until subtle adverse health effects begin to occur.
Until the EPA report, most people thought they would be exposed to dioxin only if they lived near an incinerator, a contaminated site, a pulp and paper mill or other direct source. Now we know this is not true.
According to EPA, 90% of human exposure occurs through diet, with foods from animals being the predominant pathway. Animals are exposed primarily from dioxin emissions that settle onto soil, water and plant surfaces. Soil deposits enter the food chain by ingestion by grazing animals. People then ingest dioxin through the meat, dairy products, fish and eggs they consume. A recent study by Dr. Arnold Schecter of the State University of New York at Binghampton found dioxin in many food products purchased in an upstate New York supermarket. Schecter estimated that the average daily intake of dioxin is "at least 50 times greater than what EPA estimates is a virtually safe dose of dioxin."
Who is likely to have the highest dioxin levels in their bodies? People that eat more than two inland fish meals a month. People who live near a dioxin source or eat food produced near a dioxin source. Children. Breast fed babies. Anyone who eats a lot of meat, dairy products, or fish. Dioxin is so pervasive that limiting further exposure of the American people cannot be accomplished through lifestyle or dietary changes. The only sensible way to limit further exposure is to shut down the sources of dioxin contamination.
How does dioxin damage us?
The EPA report is full of new information on dioxin including information on how dioxin and dioxin-like chemicals (PCBs, furans) damage the body. Scientists have identified a series of steps that are necessary for most if not all of the observed effects of dioxin and related compounds. Once dioxin is in the body, the molecules of dioxin (the more dioxin you are exposed to the more dioxin molecules present in the body) "attach" to specific receptor "sites" in cell tissue much like a ship pulling into a loading dock at a pier. This site is normally used by hormones and enzymes to regulate certain activities in the body. When dioxins and dioxin-like chemicals occupy this site instead of hormones and enzymes, select normal cell functions cannot be carried out. Hormone activity, developmental/reproductive and immune functions are especially vulnerable to disruption of receptor site activity.
We're Almost Full
One of the most striking findings of the report is the significance of what past dioxin exposures may mean for public health. The report identifies levels of dioxin in the human body referred to as the "body burden." According to EPA, some adverse effects of dioxins occur at levels slightly above average body burden levels currently found in the population and that "as body burdens increase within and above this range, the probability and severity as well as the spectrum of human non-cancer effects most likely will increase."
This means that, as a society, we have been accumulating dioxin and dioxin-like chemicals in our body. We are very close to "full" when it comes to the amount of dioxin that is known or expected to cause adverse health effects. It will only take a small additional exposure to "push" us over the edge and trigger adverse health effects. For most people, any exposure to dioxin, no matter how small, may lead to some adverse health effects. In other words, no amount of additional exposure to dioxin is safe.
How Do We Stop Dioxin Exposure?
No amount of additional exposure is safe. So what do we do to stop dioxin exposure? Unlike some other societal problems, we know what it would take to stop emitting dioxin.
At the 2nd Citizens' Conference on Dioxin held in St. Louis, MO in July, 1994 activists created two demands:
1) An immediate halt to the incineration of municipal, hazardous, medical, military and radioactive waste, and any such wastes incinerated in cement and or aggregate kilns, or other devices; and
2) An immediate commencement of a phase-out of the industrial production and use of chlorinated organic compounds (including plastic, PVC).
Greenpeace has called for a national strategy for zero dioxin that would include these actions:
EPA should place a moratorium on new dioxin permits.
EPA should sunset existing dioxin permits.
EPA should place a moratorium on all new incinerators and phase out the burning of chlorinated wastes at existing incinerators.
The use of chlorine and chlorine based bleaches in the paper industry should be eliminated.
A timetable for the rapid phase out of PVC should be established.
So we know what must be done. We have to get industry to place public health before private gain. And if industry won't do that voluntarily we have to get government to create laws and regulations to protect the environment and the health of the American people.
Simple, right? And we have to accomplish these tasks at a time when the prevailing political winds are calling for fewer regulations, less taxes and fewer restrictions on corporate power.
We can't effectively stop dioxin exposure without taking on some basic issues:
Our political system is broken. The vision of a democracy in which the people use their power to elect representatives to protect and advance their interest has turned into a nightmare. In this nightmare power comes from money and the ones with the most money have the most power.
Our movement is not as strong, as inclusive or as united as it needs to be. The Big 10 Environmental groups, with their ties to the President and Congress, have tended to see grassroots people as potential donors or postcard signers, not as essential players in the creation of national strategies. Grassroots activists, overwhelmed by their local battles, have not often had the time to step back and plan proactive, long-term strategies.
Organizing a group to win change is hard, harder than it used to be. People are too busy, too distrustful, or too unaccustomed to working as a group. The media adds to this trend away from community and towards rugged individualism by reporting too much bad news and not reporting about efforts to make things right. Every day we're inundated with tragic stories about things we can't do anything about. Rarely does the press cover stories about ordinary people organizing together to improve their lives.
We can't expect to win a campaign to stop dioxin exposure without overcoming the difficulties of organizing, strengthening and uniting our movement and beginning to rebuild our democracy.
But we can do it and we must do it. Not by creating a flashy 100 national organizations signed-on-but-just- on-paper-coalition where local people's involvement is limited to writing a check or sending clever postcards to their Members of Congress. This has to be hundreds of local coalitions figuring out how to work together to shut down local sources of dioxin, convince corporations to modify their production methods, and to create local, state and federal regulations and laws.
We Can Do It
Dioxin is a powerful national organizing issue. It is a serious health threat to all Americans and so it is the smokestack in everyone's backyard. Dioxin can provide the basis for building local coalitions of Viet Nam Veterans, La Leche League breast feeding advocates, farmers, indigenous people, incinerator opponents, and victims of breast cancer and endometriosis. Organizing around dioxin is a way to initiate a new dialogue with the American people on "getting government off our backs and then getting government on our side."
The EPA Reassessment of Dioxin gives us the chance to broaden and strengthen our groups and deepen our involvement in our local communities. Even if your group is deeply involved in local issues, dioxin effects everyone, and the EPA reassessment provides new, compelling information to share with Sunday school classes and PTAs. Dioxin provides grassroots activists with a way to reach new people and break through the labels that have been given us by the media and the corporations.
Dioxin can also be a powerful electoral issue. In the Times Mirror September 1994 poll, The New Political Landscape, the voting public is divided into 10 distinct political groups. Three Republican oriented groups make up 36% of registered voters. The four Democratic-oriented groups add up to 34%. The largest block of swing voters, making up 19% of the electorate, are the New Economy Independents. This group is made up primarily of high school graduates who are underemployed and not optimistic, under 50, 60% female and strongly environmentalist. According to this poll, candidates of either party need the New Economy Independents to win a majority. If stopping dioxin exposure can be made into a stated concern of these strongly environmentalist voters, no candidate can win without jumping onto our bandwagon.
What's Already Been Done
The Campaign really began when EPA scheduled public meetings in six cities in December, 1994 to hear comments on the science of the health and exposure sections of the document. With encouraging turnout from grassroots activists in most cities, the EPA heard more from the grassroots about dioxin than they had bargained for.
EPA was also forced to hold three additional dioxin public meetings in Columbus, OH, Atlanta, GA and Seattle WA in response to the demands of the grassroots.
Over 500 grassroots activists spoke to EPA, the media and the public during the meetings and at rallies and press events outside the meetings. In Columbus, OH a crowd of over 100 packed the City Council chambers. Thirty two speakers, mostly grassroots toxics activists from throughout Ohio and several other Rust Belt states, told of dioxin contamination, and the resulting health problems, they have suffered at home. Activists also held a rally in front of City Hall, using body cut-outs, tombstones, and body bags to dramatize the severe health impacts of dioxin exposure.
Comments from grassroots and environmental activists dominated the agenda in Dallas. Over 30 people spoke, representing groups from across Texas and four neighboring states, who are fighting toxic waste- burning cement kilns, medical waste incinerators, chemical waste plants, and Agent Orange-related dioxin contamination.
Speaking for the 800,000 member Texas PTA, Kim Phillips told the EPA panel, "It is not acceptable to poison or expose any child to a hazard that can be avoided. The illness and death of a child is extremely significant to parents, family, and community."
In New York, Newark, Washington, Chicago, San Francisco, Seattle and Atlanta, activists echoed the concerns raised in Columbus and Dallas. CCHW helped in the organizing of regional efforts to give testimony and focus the media's attention at the public meetings on the dioxin report. As part of this effort, CCHW mailed an alert about the dioxin report and the public meetings to 25,000 individual activists and groups. CCHW's staff have written and distributed a series of short articles on the EPA's report.
EPA's Plans
The next step for the EPA is to review the comments submitted during the period around the public meetings. A summary of these comments will be prepared and evaluated by EPA's Science Advisory Board. That will be the final scientific review of the reassessment. EPA watchers expect a final report on the health effects of dioxin should be released in the fall of 1995.
The EPA's report should lead to new federal regulations based on the reassessment. How long that policy making process will take depends, in part, on Congress. If the Contract on America advocates are successful in prohibiting all new regulations or adding elaborate cost-benefit analysis to the regulatory process, any new federal restrictions on dioxin may take two years or longer.
EPA is considering holding "dioxin policy workshops" later this year. Whether these occur, or whether EPA or Congress acts to drastically reduce dioxin exposure, is in the hands of grassroots environmental justice groups across the country.
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What is dioxin?
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