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Overview of BAT and BEP relevant to Article 5 and Annex C of the Stockholm Convention on Persistent Organic Pollutants and Environmental Impact

Assist. Prof. Dr. Siwatt PongpiachanSchool of Social & Environmental Development

National Institute of Development Administration (NIDA)

Contact: pongpiajun@gmail com

First National Awareness Workshop forDemonstration of Best Available Techniques(BAT) and Best Environmental Practices (BEP) infossil fuel-fired utility and industrial boilers inresponse to the Stockholm Convention onPersistent Organic Pollutants (POPs)

Topics1. Chemical Structures of Dioxin and Furan2. Carcinogenicity & Mutagenicity3. Genotoxicity Screening Tests4. Toxic Equivalence Factor (TEF) & Toxic

Equivalent (TEQ)5. A Study of Mutagenic Index in Bangkok’s

PM10

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Chemical Structures of Dioxin and FuranDioxins and dioxin-like compounds (DLC) are by-products of various industrialprocesses, and are commonly regarded as highly toxic compounds that areenvironmental pollutants and persistent organic pollutants (POPs).They include:

Polychlorinated dibenzo-p-dioxins (PCDDs), or simply, but inaccurately, dioxins.Technically PCDDs are derivatives of dibenzo-p-dioxin. There are 75 PCDDs, andseven of them are specifically toxic.

Polychlorinated dibenzofurans (PCDFs), or simply furans. Technically PCDFs arederivatives of dibenzofuran. There are 135 congeners (derivatives differing onlyin the number and location of chlorine atoms). Whilst they strictly speaking arenot dioxins, ten of them have "dioxin-like" properties.

Polychlorinated biphenyls (PCBs), which also are not dioxins, but twelve of themhave "dioxin-like" properties. Under certain conditions PCBs may form moretoxic dibenzofurans through partial oxidation.

Finally, dioxin may refer to dioxin proper, the basic chemical unit of the morecomplex dioxins. This simple compound is not persistent and has no PCDD-liketoxicity.

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Polychlorinated dibenzo-p-dioxins (PCDD or DIOXINS)

Homologue PCDD

1-Cl MCDD

2-Cl DCDD

3-Cl TrCDD

4-Cl TCDD

5-Cl PeCDD

6-Cl HxCDD

7-Cl HpCDD

8-Cl OCDD

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Structure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

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Polychlorinated dibenzofurans(PCDF or FURANS)

Homologue

PCDF

1-Cl MCDF

2-Cl DCDF

3-Cl TrCDF

4-Cl TCDF

5-Cl PeCDF

6-Cl HxCDF

7-Cl HpCDF

8-Cl OCDF

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Structures of the ten 2,3,7,8-substituted PCDF congeners that are toxicologically of most relevance

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Polychlorinated biphenyls (PCBs)

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1,4-dioxin

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CARCINOGENICITY & MUTAGENICITY

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MUTATION A change in the DNA moleculeProcess which produces changes in the DNA that may be inherited.

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MUTAGENICITY= mutagenic activity= genotoxicity (genotoxic activity)Mutagenic (genotoxic) compound = a compound that causes mutationMutations in certain genes could lead to malignant transformation of the cell.Many mutagens are supposed to be carcinogenic.

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CARCINOGENSKarkinos (Greek) =crayfish

Compounds or otherfactors that inducetransformation of a normalcell into a tumor one

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Benzo(a)pyrene

Polycyclic aromatic hydrocarbon

Carcinogenic activity confirmed

A product of combustion processes (e.g.

tobacco smoking)

A typical promutagenic agent

Metabolic conversion (addition of epoxide

group and two OH-groups).

A metabolic product binds to DNA →

adduct (a compound that results from

addition).

Presence of adduct can cause mutation.

Metabolic conversio

n

binds to DNA

BaP – guanin adduct

CLASSIFICATION OF MUTAGENSChemical (different compounds)Alkylating agentsAromatic hydrocarbons (e.g. benzo(a)pyrene)Intercalating agents (e.g. fluorescent dyes)Artificial derivatives of DNA basesPhysical (ionizing radiation, UV-radiation)Biological (viruses, transposable elements)

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Genotoxicity Screening Tests

1. On molecular level (Comet Assays)

2. On gene level (Ames Test)

3. On chromosomal level (Micronucleus Test)

Comet Assay

Ames Test

Micronucleus Test

Toxic Equivalence Factor (TEF)

Toxic Equivalency Factors (TEFs) are toxicity potency factors that are

used by the World Health Organization (WHO) and by scientists and

regulators globally as a consistent method to evaluate the toxicities of

highly variable mixtures of dioxin compounds. In the dioxin family,

2,3,7,8-TCDD is the "habanero" of the bunch, the most studied and the

most toxic member, and it is assigned a TEF of one. (One other dioxin-

like compound, 1,2,3,7,8-PnCDD, also has a TEF of one.) The other

family members are less toxic than 2,3,7,8-TCDD, and are also much

less studied on an individual basis.

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Toxic Equivalence Factor (TEF)

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Toxic Equivalent (TEQ)

Getting to a Total Dioxin-TEQ:To obtain the total toxicity of a particular mixture of dioxin compounds, it is necessary to know how much of each compound, in grams, exists in the mixture. These mass quantities are then multiplied by the corresponding TEFs for the compounds and all of the resulting products are added together.

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A Study of Mutagenic Index in Bangkok’s

PM10

Monitoring Stations in Bangkok (PCD)

No. MonitoringStations

1 Din-Daeng Community

2 Wat-Sing High School

3 Choc-Chai Police Station 4

4 Nonsi Witthaya School

5 The Metropolitan Electricity Authority the Sub Station of Thonburi

6 Klong Chan Community

7 Bodindecha

Extraction Evaporation Blowdown

THANK YOU FOR YOUR ATTENTION

Assist. Prof. Dr. Siwatt PongpiachanProject Manager: Demonstration of BAT/BEP for Fossil

Fuel Fired Utilities and Industrial Boilers in Thailand

Contact: pongpiajun@gmail.com

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