Dioxins and Dioxin-like compounds (DLCs) are compounds that are highly toxic environmental persistent organic pollutants (POPs). They are mostly by-products of various industrial processes – or, in case of dioxin-like PCBs and PBBs, part of intentionally produced mixtures.
Polychlorinated dibenzo-p-dioxins (PCDDs), or simply dioxins. PCDDs are derivatives of dibenzo-p-dioxin. There are 75 PCDD congeners, differing in the number and location of chlorine atoms, and seven of them are especially toxic, the most dangerous being 2,3,7,8-Tetrachlorodibenzodioxin (TCDD)
Polychlorinated dibenzofurans (PCDFs), or furans. PCDFs are derivatives of dibenzofuran. There are 135 isomers, ten have dioxin-like properties.
Polychlorinated/polybrominated biphenyls (PCBs/PBBs), derived from biphenyl, of which twelve are “dioxin-like”. Under certain conditions PCBs may form dibenzofurans/dioxins through partial oxidation.
Finally, dioxin may refer to 1,4-Dioxin proper, the basic chemical unit of the more complex dioxins. This simple compound is not persistent and has no PCDD-like toxicity.
Polychlorinated dibenzo-p-dioxins :
Polychlorinated dibenzofurans :
Polychlorinated biphenyls :
Because dioxins refer to such a broad class of compounds that vary widely in toxicity, the concept of toxic equivalency factor (TEF) has been developed to facilitate risk assessment and regulatory control. Toxic equivalence factors (TEFs) exist for seven congeners of dioxins, ten furans and twelve PCBs. The reference congener is the most toxic dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) which per definition has a TEF of one.
In reference to their importance as environmental toxicants the term dioxins is used almost exclusively to refer to the sum of compounds (as TEQ) from the above groups which demonstrate the same specific toxic mode of action associated with TCDD. These include 17 PCDD/Fs and 12 PCBs. Incidents of contamination with PCBs are also often reported as dioxin contamination incidents since it is this toxic characteristic which is of most public and regulatory concern.
So, Lets learn about Dioxin in the prescriptive of a layman or a normal person who knows Science,
WHAT ARE DIOXINS?
“Dioxins” refer to a family of chlorine-based chemical compounds most often formed as a result of combustion processes such as commercial or municipal waste incineration and from burning fuels (like wood, coal or oil). Dioxins can also be formed when household trash is burned and as a result of natural processes such as forest fires. Chlorine bleaching of pulp and paper, certain types of chemical manufacturing and processing, and other industrial processes all can create small quantities of dioxins. Cigarette smoke also contains small amounts of dioxins. It is important to clarify that dioxins do not naturally occur as “dioxins” in the environment; they are formed through the process of heating or burning a material containing elements which react with heat to form dioxins.
Dioxins: Is there an organic advantage?
There is no way to control the dioxins that settle on crops and fields – whether organic or conventional – as the result of industrial or residential burning. However, organic production practices do reduce dioxin exposure through reduced use of synthetic herbicides and pesticides. There are no studies comparing the dioxin levels of organic and non-organic animal products, but it is reasonable to assume that, because organic livestock would not be consuming as many dioxins through their feed, their milk and meat products would similarly show lower dioxin levels.
Each year over 1.2 billion pounds of synthetic chemicals are disposed of or applied to our land or disposed directly into our waters. Nothing on earth is free from this “toxic burden.” In fact, this is why the organic industry was birthed: to restore our soil to health and to bring awareness to the public of this pollution. The organic promise is to do everything possible to reduce the amount of harmful chemicals in our Food, our bodies, and the earth. Organic food and farms cannot promise 100% pure food, but in test after test of organic foods versus conventional foods, organic consistently shows significantly less residue than conventional.
What is the advisory exposure level for Dioxins?
EPA and FDA have not established an advisory level for dioxin. The World Health Organization (WHO) has established a provisional tolerable monthly intake (PTMI) of dioxins and related compounds of 70 picograms/kilogram body weight (pg/kg). Unfortunately, food is not regularly tested for dioxins because they are present in the environment worldwide and are also formed by some natural processes. Therefore, it is not economically practical to test all food for dioxin levels. Since there is no way to know exactly how much dioxin you are consuming, we recommend following the precautionary principle which advises taking proactive, preventative measures to reduce your personal exposure to known sources.
What are the sources of Dioxin exposure?
One’s exposure level somewhat depends on location and distance from a dioxin emitting source. Dioxins are produced by a wide range of manufacturing processes including smelting, chlorine bleaching of paper pulp, the manufacturing of some herbicides and pesticides, waste incinerators2, and the uncontrolled burning of residential waste1. Vinyl/polyvinyl chloride plastics (PVC, or #3 plastics) will also release dioxins when heated, such as by the sun or in the microwave. PVC/#3 plastics include PVC pipes, siding and other building materials, as well as common cling wrap and some plastic food storage containers.
Once dioxins are released into the environment they settle on crop and pasture land, whether through the application of synthetic pesticides and herbicides, or traveling for miles on microscopic pieces of dust and ash, and those crops and pasture are then ingested by livestock animals. More than 90% of human exposure to dioxins is through the food supply, mainly high fat-content meat and dairy products, fish (especially freshwater fish) and shellfish2, 3. Dioxins endure a long time in the body because they are stored in fatty tissue, and dioxins tend to accumulate in the food chain (i.e.: the higher an animal is in the food chain, the higher the concentration of dioxins in its body). Their half-life in the body is estimated to be seven to eleven years1. Because humans are at the top of the food chain, we can accumulate dioxins very quickly. Breast milk has a very high fat content, so a nursing infant has a greatly increased risk of exposure through its mother3.
What can I do to reduce my risk of exposure to Dioxins?
The best way for an individual to reduce their risk of exposure to dioxins is to reduce their intake of dioxins through food. EPA does not recommend avoiding particular foods because of dioxins; however, switching to an organic diet significantly reduces one’s intake of synthetic herbicides and pesticides which contain dioxins, and reducing one’s intake of animal fats including red meat, fish and dairy will reduce exposure. Chicken has been shown to have less dioxin levels than other meats. You can also control your immediate exposure by not burning trash , switching to glass containers for use in the microwave and replacing vinyl siding.