This document provides information about dioxin, including its properties, effects, and methods of control. It defines dioxin as a class of chlorinated chemical compounds that are extremely stable and persistent in the environment. The document outlines the toxic effects of dioxin exposure on human health, especially long-term effects on the immune, endocrine, and reproductive systems. It also discusses major sources of dioxin in the environment and methods to prevent and control dioxin emissions, especially from waste incineration. The key points are that dioxin exposure poses health risks like cancer, and controlling combustion conditions and installing emission controls are important for reducing environmental dioxin levels.

1. DIOXIN
PROPERTIES,
EFFECTS
AND
CONTROL
By SUBODH ANAND MAHANUR
M.TECH ENVIRONMENTAL ENGINEERING (FIRST YEAR)
1
Under the guidance of Dr. P. P. Bhave

2. What is Dioxin ?
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 Dioxin is a general name for a class of chlorinated
chemical compounds with similar chemical structure.
 It includes PCDD’s, PCDF’s, and dioxin like PCB’s.
 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin is often
referred to as TCDD or “dioxin”.
 The chemical formula for TCDD is C12H4Cl4O2

3. Molecular structure of dioxin
3

4. Properties
 Dioxins with four or more chlorines in their molecular
structures are extremely stable.
 It means they do not breakdown or change into other
substances.
 That is why they are called as Persistent Organic
Pollutants (POPs).
 In EPA's dioxin report, they refer to dioxin as
hydrophobic (water-fearing) and lipophilic (fat-loving).
 In this way they accumulate in food chain, mainly in fatty
tissues of animals.
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6. Dioxin and Furan congeners
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7. Toxic Equivalents(TEQ)
 To evaluate the toxicity of all dioxin-like substances
present in the sample
 To observe combined effect of all dioxins and dioxin-like
substances present
 TEQ = (concentration of dioxin)*(toxicity factor)
 Total TEQ = Sum of all TEQ present in sample
 2,3,7,8-TCDD is used as a reference and given a TEF of
1
 Each of the 17 toxic dioxins/furans is then assigned a
toxicity factor that estimates its toxicity relative to TCDD
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8. Toxic Equivalent Factors (TEF) for
Dioxins and Furans8

9. Sources
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 Natural processes such as volcanic eruptions and forest
fires
 Uncontrolled waste incinerators (solid waste and
hospital waste) due to incomplete burning
 Metallurgical processes such as high temperature steel
production, smelting operations and scrap metal
recovery furnaces

10. 10
 Cement kiln burning, coal-fired electricity generation
and backyard burning of household trash
 Manufacturing processes including chlorine bleaching of
paper pulp
 Manufacturing of some herbicides and pesticides

11. Point sources of dioxin
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12. Non point source of dioxin
12

13. Estimates of anthropogenic
sources of dioxins in the US13
Source g of TEQ per year
Municipal waste incineration 1100
Backyard trash burning 1000
Landfill fires 1000
Secondary copper melting 541
Medical waste incineration 447
Forest fires 208
Cement kilns 171
Iron ore sintering 100

14. Dioxin Emission Pathways
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Dioxin and Furan emissions from combustion sources
can be explained by three principal pathways.
 Feed material going to the incinerator contains dioxin
and/or furan
 Formation of dioxin from thermal breakdown and
precursor compounds
 De novo synthesis

15. How are we exposed to dioxin?
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 The major sources of dioxin are in our diet.
Today people are exposed to dioxins primarily by
eating food, in particular animal products,
contaminated by these chemicals.
 Since dioxin is fat-soluble, dioxins are absorbed
and stored in fat tissue and, therefore, accumulate
in the food chain.
 More than 90 percent of human exposure is
through food.

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18. Effects of dioxins on human health
Short-term exposure
 Skin lesions, such as chloracne
 Patchy darkening of the skin
 Altered liver function
 Dermatitis
 Gastrointestinal problems.
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 Long term exposure - effects on
 Immune system
 Endocrine system
 Reproductive system
 Nervous system
 Cardiovascular system

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Long-term exposure – effects on
 Immune system
 Dioxin directly reduces the number of B-cells(immune
cells that develop in bone marrow, then circulate
throughout the blood and lymph, fighting off invaders)
and it reduces number of T-cells( immune cells that
develop in thymus)
 EPA concludes that the even low doses dioxin attack the
immune system.

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 Endocrine System –
 Dioxin is an endocrine disruptor results in human health
effects including lowered fertility and and increased
incidence of “endometriosis”.
 Endometriosis : It occurs when cells from the lining of
womb(uterus) grow in other areas of the body causing
pelvic pain, especially associated with menstruation.

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 Reproductive system –
 Decrease in sperm production by almost 50%
 Lower Infertility among young men
 Increased risk of Cryptochidism
 Decrease in testosterone (a male sex hormone that is
important for sexual and reproductive development)
 Nervous system –
 Causes nerve damage, birth defects
 Delay in nervous system development

23. Carcinogenic Dioxin
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 TCDD dioxin is listed as a human carcinogen in
the Thirteenth Report on Carcinogens published by the
National Toxicology Program because it causes
cancer, particularly lung cancer.
 Based on animal data and on human epidemiology data,
TCDD was classified as a "known human carcinogen”
by WHO’s International Agency for Research on
Cancer (IARC)

24. Sensitive groups to dioxin exposure
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 The developing fetus is most sensitive to dioxin
exposure through the pregnant woman’s placenta.
 New-born can be exposed to dioxins through breast
milk.
 High consumers of fish in certain parts of the world.
 Workers in the pulp and paper industry, in incineration
plants and at hazardous waste sites.

25. Dioxin Contamination Incidents
 Large amounts of dioxins were released in a serious
accident at a chemical factory in Seveso, Italy, in 1976.
 2,3,7,8-TCDD, was released into the air and eventually
contaminated an area of 15 square kilometres where
37 000 people lived.
 Within days a total of 3,300 animals were found dead,
mostly poultry and rabbits. 447 people were found to
suffer from skin lesions or chloracne.
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26.  In 1999, high levels of dioxins were found in animal
based food (poultry and eggs, pork)from Belgium.
 The cause was traced to animal feed contaminated with
illegally disposed PCB-based waste industrial oil.
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27.  A few cases of intentional human poisoning have also
been reported. The most notable incident is the 2004
case of Viktor Yushchenko, President of the Ukraine,
whose face was disfigured by chloracne.
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28. Prevention and Control
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 Control during incineration
1. Improvement of combustion conditions
2. Control of the temperature-time profile of flue gases
3. Separation of fly ashes
4. Injection of inorganic additives
5. Injection of organic additives

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 Removal of PCDD/Fs in exhaust gases
1. Scrubber coupled with bag filter or electrostatic
precipitator
2. Activated carbon adsorption
3. Catalytic filter and the combined dioxin and NOx
destruction
4. Process of electron beam radiation

30.  Injection of inorganic additives
Adding inhibitors or blockers to inhibit the generation of
dioxin in incineration process is a main dioxin control
method which is widely used.
Inorganic inhibitors include basic compounds, ammonia.
Ammonia is commonly used in the joint removal of NOx
and PCDD/F.
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 Improvement of combustion conditions
Complete destruction of dioxin and furans in waste
material during combustion is achieved through 3-T rule.
Temperature > 900°C
Time > 1.5 sec
Turbulence – Re > 10000

32.  Catalytic filter and the combined dioxin and NOx
destruction
 Mainly carbon dioxide and HCl result as destruction
products.
 It can reduce the concentration of PCDD/Fs in the
exhaust gases to below 0.1 ng TEQ/Nm3.
 The reactor used for the removal of PCDD/Fs separately
is the catalytic filter.
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33. Reducing dioxin exposure on
personal level
 Remove skin from fish and chicken
 Wash fruits and vegetables to remove any leftover pesticide
or herbicide before eating
 Select cuts of meat that are naturally lean, or trim visible fat
 Use fat-free or low-fat milk and use butter in moderation
 While catching fish from pond or stream, check local fishing
advisories
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34. Risk assessment by US-EPA
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 2,3,7,8-tetrachlorodibenzo-p-dioxin is a human
carcinogen
 The general public’s exposure to ambient levels of
dioxins may cause up to 1 case of cancer for 1000
people exposed; however, the true risks are likely less
than that.
 There does not appear to be a “threshold” or safe dose,
of dioxins that does not cause toxic (non-cancer) effects

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 U.S. residents are exposed daily to about one picogram
dioxins per kilogram body weight (pg/kg bw), meaning
their exposure is close to the level that caused biological
changes in animals
 Emissions of dioxins have declined more than 80
percent since 1987
 Open burning of household waste is one of the largest
known, non-regulated sources of dioxins

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37. Reporting Units
1 milligram (mg) 0.001 g
1 microgram (µg) 0.000001 g
1 nanogram (ng) 0.000000001 g
1 picogram (pg) 0.000000000001 g
1 femtogram (fg) 0.000000000000001 g
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38. References
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 Daniel Vallero (2014) “Fundamentals of Air pollution” , chapter-6,
page-152
 A. Schecter (1994) “Dioxins and Health”
 Levels and congener distributions of PCDDs, PCDFs and dioxin-
like PCBs in environmental and human samples: a review K.
Srogi,2007
 WHO report on EXPOSURE TO DIOXINS AND DIOXIN-LIKE
SUBSTANCES : A MAJOR PUBLIC HEALTH CONCERN, 2010
 Lois Marie Gibbs(2000) “Dying from Dioxin”

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THANK YOU