Dioxins are environmental pollutants. They are of concern because of their highly toxic potential. Dioxins have the dubious distinction of belonging to the “dirty dozen” - a group of dangerous chemicals known as persistent organic pollutants.
Dioxins have been present in the environment since the 1800s. The term "dioxin" actually refers to a group of chemicals which have a similar chemical structure. These chemicals include chlorine.
Some 419 types of dioxin-related compounds have been identified but only about 30 of these are considered to have significant toxicity, with tetrachlorodibenzo para dioxin (TCDD) being the most toxic.
Why should I be aware of this?
Dioxin is formed when chlorine - containing chemicals, like plastics or industrial wastes, are burned, whether in a municipal incinerator or a home wood - burning stove. The chemical enters the food chain when animals eat contaminated plants, and it accumulates in the fat of mammals and fish.
How does this affect me?
- Experiments have shown they affect a number of organs and systems.
- Once dioxins have entered the body, they endure a long time because of their chemical stability and their ability to be absorbed by fat tissue, where they are then stored in the body.
- Their half-life in the body is estimated to be seven to eleven years.
- In the environment, dioxins tend to accumulate in the food chain. The higher in the animal food chain one goes, the higher is the concentration of dioxins.
All about dioxins
The chemical name for dioxin is: 2,3,7,8- tetrachlorodibenzo para dioxin (TCDD).
- Unlike PCBs which were used in several industrial applications, dioxins have no uses.
- Dioxins are unwanted by products of a wide range of manufacturing processes including smelting, chlorine bleaching of paper pulp and the manufacturing of some herbicides and pesticides. In terms of dioxin release into the environment, waste
- They are formed unintentionally and predominantly released as byproducts of human activities such as incineration and fuel combustion.
- They are also formed in minor quantities by natural processes such as forest fires and volcanoes.
- Dioxins travel through the air and deposit on water or land.
- In water, dioxins initially bind to small particles or plankton.
- On land, dioxins deposit on plants or bind to the soil, most often without contaminating groundwater.
- Animals accumulate dioxins in fat through their food; concentrations increase at each step in the food chain.
Many countries monitor their food supply for dioxins. This has led to early detection of contamination and has often prevented impact on a larger scale. *Increased dioxin levels were detected in milk in 2004 in the Netherlands. This was traced to a clay used in the production of the animal feed.
- In July 2007, the European Commission issued a health warning after high levels of dioxins were detected in a food additive - guar gum - used as thickener in small quantities in meat, dairy, dessert or delicatessen products.
- In 1999, high levels of dioxins were found in poultry and eggs from Belgium.
- Another case of dioxin contamination of food occurred in the United States of America in 1997. Chickens, eggs, and catfish were contaminated with dioxins when a tainted ingredient (bentonite clay, sometimes called “ball clay”) was used in the manufacture of animal feed. The contaminated clay was traced to a bentonite mine.
- Large amounts of dioxins were released in a serious accident at a chemical factory in Seveso, Italy, in 1976. A cloud of toxic chemicals, including 2,3,7,8-Tetrachlorodibenzo-p-dioxin, or TCDD, was released into the air and eventually contaminated an area of 15 square km.
Who is most at risk?
- The developing fetus is most sensitive to dioxin exposure.
- The newborn, with rapidly developing organ systems, may also be more vulnerable to certain effects.
- Some individuals or groups of individuals may be exposed to higher levels of dioxins because of their diets. They might be high consumers of fish in certain parts of the world.
- People in certain occupations such as workers in the pulp and paper industry, in incineration plants and at hazardous waste sites, are also at a higher risk.
Dioxin and health
- A draft report by The Environmental Protection Agency (EPA) says dioxin may be ten times more likely to cause cancer than previously estimated.
- The EPA report suggests a relatively high risk of cancer from exposure to dioxin for older people who eat large amounts of fatty meats and dairy products contaminated with the chemical.
- Children, too, may be at risk since the toxin is linked to developmental delays, disruption of hormone secretions, and irregularities of the immune system.
- The report concludes that children's intake of dioxin is greater than that of adults because the chemical is found in dairy products, even breast milk.
Dioxin and environment
In terms of dioxin release into the environment, waste incinerators (solid waste and hospital waste) are often the worst culprits, due to incomplete burning.
Although formation of dioxins is local, environmental distribution is global. Dioxins are found throughout the world in practically all media. The highest levels of these compounds are found in some soils, sediments and food, especially dairy products, meat, fish and shellfish. Very low levels are found in plants, water and air.
What can I do?
- Trimming fat from meat may decrease the exposure to dioxin compounds.
- Do not burn trash in your backyard.
- Eat a low-fat diet.
- Eat a well-balanced diet
- Since many dioxins contain chlorine or are by-products of processes involving chlorine compounds, Greenpeace is demanding a ban on all industrial uses of chlorine.
- Don't buy bleached paper products.
- Cut down on your use of plastics (including little items, such as baby pacifiers, plastic food containers, and ice cube tray.
- Do not burn plastic.