Dioxin

Synonyms

a)           2,3,7,8 – tetrachlorodibenzodioxin

b)           TCDD

Four chlorine, a couple oxygens and 2 benzene rings make a dioxin molecule

C₁₂H₄Cl₄O₂

Melting point

295o C

Boiling point

500o C

Water Solubility

1.9 x 10^-7 g/100mL

Physical Appearance

Colorless to white crystals

Dioxin is often used as catch-all term for three acutely toxic chemical groups:  true dioxins, furans and polychlorinated biphenyls (PCBs).  What all of these groups have in common are two benzene rings and chlorine molecules.  The toxicity of other dioxins, furans and PCBs are all considered in comparison to TCDD.

Origin/Sources Of Emission

1.                  Process that burn chlorine with organic matter (such as waste incineration)

2.                  Wastewater discharged from the pulp and paper industry’s bleaching process.

3.                  Pulp and paper mills are the third largest known source of dioxin emissions.  Most of their emissions are released via wastewater discharges.  The wood used to produce paper contains lignin, a dark-colored substance that must be removed in order to produce white paper.  Chlorine acts to separate the lignin form the pulp which can be removed.  When chlorine is used as the “bleaching” agent then appears in the paper products, and in the wastewater and sludge from the mills.  Dioxin-contaminated wastewater runs into the bodies of water, where the dioxin concentrates in the aquatic food chain, ending up in fish.  The dioxin contaminated sludge from paper mills, which is mostly landfilled, represents one of the bigger dioxin reservoirs.  Alternatively, some paper mills spread their sludge on land which poses a significant risk to people and wildlife.  Others burn their sludge, which releases very high levels of dioxin into air.

4.                  Dioxin that gets into the pulp ends up in paper products.  If the paper is used for the packaging food products, dioxin can contaminate the food.  U.S Food and Drug Administration found that dioxin migrated into food from coffee filters, cream cartons, orange juice cartons, paper cups used for hot beverages and soup, paper plates used for hot food, dual ovenable trays and microwave popcorn bags.  According the FDA, dioxin levels in these paper product ranged from 1 to 13 parts per trillion (ppt)  When bleached paper products are discarded and burned or buried, the dioxin contained in them can re-enter the environment.

AFFECTS ON HEATH

1.      Dioxin causes cancer in animals including humans

2.      Dioxin causes high infant mortality, contaminated breast milk, decreased fertility in women, increased miscarriage rates and alteration in the ovarion cycle, decreased sperm count, hormonal changes and reproductive including endometriosis.

3.      Dioxin has been linked with genetic abnormalities.

4.      In Maine people are advised to eat no more than 2 meals per year of fish from the Penobscot, Androscoggin and Kenebec Rivers, because of high dioxin concentrations.

5.      Dioxin has a half-life of 7 – 11 years and accumulates in our bodies throughout our life.

6.      Other health effects include:  Chloracne, increased liver size thyroid damage, diabetes, neurological damage, respiratory problems, decreased immune responses, decreased male sex hormone, sperm loss and endometriosis.

7.      Lowered viability offspring

8.      Posing a significant threat to wildlife

9.      Dioxin can alter the number of Epidermal Growth Factor (EGF) receptors in various developing tissues (e.g: yellowish-brown discoloration of teeth in children exposed to extremely high concentration of dioxin like compounds.

How does dioxin get in our body?

Dioxin is formed when chlorine-containing chemicals, like plastic or industrial waste, are burned, or when pulp or paper are bleached.  The chemical then becomes airborne, settling on plants that are eaten by animals, which, in turn are eaten by humans.  Humans retain dioxin in their fatty tissue through both meat and dairy consumption.  And once dioxin is lodged in the body there it remains. (Bioaccumulation)

How does dioxin do so much damage once it gets into the body?

It attaches to cell receptors that are designed for regulatory hormones and enzymes.  The result-normal cell function including DNA can run amok.