DIOXINAS, FURANOS PCBs

PFOS

2011

2

¿Qué son los COPs?

Tóxicos, Persistentes, Bioacumulables,

Contaminantes globales

Tóxicas: en muy bajas concentraciones afectan la salud de

las personas, animales y el medio ambiente.

Persistentes: tienen muy lenta degradación física, química

o microbiológica.

Bioacumulables: por sus características físico-químicas se

acumulan en tejidos grasos, biomagnificándose al subir en

la cadena alimenticia.

Contaminantes globales: se dispersan por el medio

ambiente por medio de corrientes de aire, marinas, ríos y en

los seres vivos, encontrándose en el agua, sedimentos,

animales y personas incluso en zonas remotas.

3

¿Cuáles son?

• Plaguicidas organoclorados: Aldrin, Clordano,

DDT, Dieldrin, Endrin, Heptacloro,

Hexaclorobenceno, Mirex y Toxafeno,

• Bifenilos Policlorados (PCBs) usado como

aceite dieléctrico en transformadores y

acumuladores y otros usos.

• Dioxinas y Furanos: subproductos no

intencionales generados por combustión y en

algunos procesos industriales cuyos insumos

contienen cloro.

4

Convenio de Estocolmo

Objetivo: Proteger la salud humana y el medio

ambiente frente a los Contaminantes Orgánicos

Persistentes (Art.1)

Chile al ratificarlo se compromete a definir medidas

para reducir y/o eliminar las emisiones derivadas de la

producción y el uso de estas sustancias.

Conama, punto focal del Convenio de Estocolmo

5

Convenio de Estocolmo

Antecedentes Mayo de 2001, Estocolmo, firma del Convenio por

parte de 102 países, incluido Chile.

Mayo de 2004, El Convenio entra en vigor.

Enero de 2005, Es ratificado por Chile (A la fecha111 países lo han ratificado)

Mayo de 2005, Punta del Este Uruguay, se realiza la Primera Conferencia de las Partes

19 de mayo de 2005, Se publica en el Diario Oficial

What Are “Dioxins”?

A family of structurally related chemicals

which have a common mechanism of

action and induce a common spectrum of

biological responses

Dioxins

75 congeners

7 toxic

PCBs

209 congeners

12 toxic

Furans

135 congeners

10 toxic

2,3,7,8-TCDD

1,2,3,7,8-PeCDD

1,2,3,4,7,8-HxCDD

1,2,3,6,7,8-HxCDD

1,2,3,7,8,9-HxCDD

1,2,3,4,6,7,8-HpCDD

1,2,3,4,6,7,8,9-OCDD

2,3,7,8-TCDF

1,2,3,7,8-PeCDF

2,3,4,7,8-PeCDF

1,2,3,4,7,8-HxCDF

1,2,3,6,7,8-HxCDF

1,2,3,7,8,9-HxCDF

2,3,4,6,7,8-HxCDF

1,2,3,4,6,7,8-HpCDF

1,2,3,4,7,8,9-HpCDF

1,2,3,4,6,7,8,9-OCDF

3,3',4,4'-TeCB

3,3',4,4',5-PeCB

3,3',4,4',5,5'-HxCB

Cl

Cl

Cl

Cl

2,3,7,8-Tetrachlorodibenzofuran

O

2,3,7,8-Tetrachlorodibenzo-p-dioxin

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

Cl

Cl

3,3',4,4',5,5'-Hexachlorobiphenyl

Dioxin-Like Compounds

Dioxinas

Furanos

b

b

b

b

a

a

b

b

Molecular structure of

1,2,3,4,6,7-hexa-CN

Molecular structure of 2,3,7,8-

Tetrachlorodibenzo-p-dioxin

Introduction Methods

9

10

b

b

b

b

a

a

Results

.

SummaryMethods Results

Naftalenos PolNaftalenos Policlorados

2,3,7,8-Tetrachlorodibenzo-p-dioxin

“The Most Toxic Man-Made Compound”

• Prototype for family of structurally related compounds

• Common mechanism of action

• Common spectrum of biological responses

• Environmentally and biologically persistent

(Basis for TEQ approach)

Why the Interest in Dioxins???

• 1899 – ChloracneCharacterized

• 1929 – PCBs produced commercially

• 1947 – “X” Disease in cattle

• 1949 – Nitro, West Virginia

• 1957 – Chick Edema Disease; TCDD identified in TCPs

• 1962-1970 – Agent Orange use in Southeast Asia

• 1968 – “Yusho” oil disease

• 1971 – Times Beach; TCDD causes birth defects in mice

• 1973 – PBB contamination in Michigan

• 1976 – Seveso, Italy

• 1978 – Kociba rat cancer study

• 1979 – “Yucheng” oil dieases

• 1981 – Capacitor fire in Binghamton, NY

• 1985 – 1st US EPA health assessment of TCDD

• 1991 – NIOSH cancer mortality study of US workers

• 1999 – Belgium dioxin poisoning; Viennese poisoning

“Dioxins”Polyhalogenated Dibenzo-p-dioxins and furans

Never produced intentionally

Unwanted byproducts of industrial and combustion

processes

Polyhalogenated Biphenyls, Naphthalenes,

Azo/azoxybenzenes

Commercially produced

Major industrial chemicals

Limited number of congeners have dioxin-like properties

Lateral halogenation

> 3 Halogens

Chlorinated, brominated, and mixed chloro-bromo

congeners

Dioxin-Like Compounds

• Semivolatile

• Lipophilic

• Hydrophobic

• Persistent

• Bioaccumulating

• Toxics

PCBs

• Large Family of Chemicals– 209 Possible Congeners

– Small Subset Are “Dioxins”

– NEVER have PCBS without Dioxin-like

PCBs

• Majority Have Own, Inherent,

Toxicities– Multiple, Overlapping, Structural Classes

– Can Interact Additively, Synergistically,

and/or Antagonistically With Dioxins and

With Other PCB Congeners

TCDD is NEVER Found Alone

• Complex Mixtures Exist both

Environmentally and in Animal and Human

Tissues

• TCDD is only a Small Part of Total

Chemical Mass

• We have the Most Toxicological

Information about TCDD

Toxic Equivalency Factors (TEFs)

• Developed for Risk Assessment

• Interpret Complex Database Derived from Analysis of Samples Containing Mixtures of Dioxin-like Chemicals

• Express Quantitatively the Toxicity of a Chemical in terms of an Equivalent concentration of TCDD (Relative Potency)

• ∑([Chemical] x TEF)PCDD/PCDF/PCB=TEQ

Five Compounds Make up about 80+%

of the Total TEQ in Human Tissues

• Four of 17 Toxic PCDD/PCDF Congeners

– 2,3,7,8-TCDD

– 1,2,4,7,8,-PeCDD

– 1,2,3,6,7,8-HxCDD

– 2,3,4,7,8-PeCDF

• One of the 12 Toxic PCBs

– PCB 126

Major Past Sources of Dioxins (20th

Century Problem)

• Chloralkali Facilities

• Chlorinated herbicide and biocide Production

• Leaded Gasoline

• Municipal, Medical, and Hazardous Waste Incineration

• Chlorine Bleaching of Paper and Pulp Products

Recently Identified Sources

• Open Burning of Household Waste

• Uncontrolled Combustion

– Forest Fires and Volcanos

• Metal Refining

From Factory to the FetusDioxins and PCBs: Pathways of Exposure

and Neurodevelopmental Effects

Dioxins:PVC ManufacturingMedical/Municipal Incinerator

PCBs:TransformersLandfillsHazardous Waste Sites

AIR

SOIL

WATER

FOOD

DioxinsPCBs

PCBs

How do Dioxins Move in the

Environment

• If emitted into air, undergo atmospheric transport

and deposition on land or water

• If emitted into water, bind to sediment

• Recycle in environment

• Bioaccumulate up the food chain

• Resistance to physical, chemical, and biological

degradation

• Dioxins are less mobile than Hg or the more volatile PCBs.

• Dioxins do not appear to exhibit global retort, or

strong “grasshopper” effect.

• Dioxins are continually exchanged among media and

should be viewed as a complex system of stocks and flows

Dioxin Environmental Mobility

Reentrainment

SOURCESTRANSPORT

DEPOSITION

FOOD

SUPPLY

Runoff

Erosion

Combustion

Industrial

Processes

Direct

Discharge

Sources and Pathways to Human Exposures

How are People Exposed?

• Dioxins are omnipresent

• Majority of exposure (>95%) is via microcontamination of food– Meat, fish, dairy

• Sensitive Subpopulations with High Exposure– Subsistence Fishers and Hunters

– Nursing Infants

– Occupational Workers• Oral, dermal, and inhalation exposures

How You are Exposed Makes Little

Difference

• Dioxins are well absorbed from the GI tract and lungs

– Skin absorption is limited and slow

• Dioxins primarily lodge in the liver and fat

• Dioxins are primarily eliminated after metabolism, which is VERY slow

Why do the Body Burdens Increase

Over Time?

• Persistence– Resistance to Biological, Chemical, and Physical

Degradation

– Long Half-Lives in Animals and People• More Body Fat-Longer Half-Life

• Half-Life is Dose-Dependent

• Bioaccumulation– Due to Persistence in Animal tissues Higher Trophic

Organisms have Higher Concentrations

– Older Organisms have Higher Body Burdens than Young

Half-Life Varies with Body Burden

and Body Composition (Emond et al., 2004)

209.79206.29

194.25

157.67

104.17

50.69

27.96

18.6313.57

10.88 9.46 8.71

217.71 215.88212.75

203.00

171.75

114.54

61.50

33.96

22.2918.33 17.2916.58

0.00

50.00

100.00

150.00

200.00

250.00

1.00E-07 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03

Dose ug/kg de BW

T1

/2 (

da

y)

6.9% FAT

25% FAT

Experimental exposure

Occupational exposure

Background Human exposure

Trace Levels --- Highly Toxic

• Soil, Food --- PPT

• Water --- PPQ

• Air --- fg/m3

• Human Serum ---PPT

• Intake --- 1pg/kg/d TEQ

• Upper Bound Cancer Risk 1x10-3

• Non-Cancer MOE < 10

21%

16%

19%

14%

5%

4%

7%

6%

1%

Soil ingestionSoil dermal contact

Freshwater fish andshellfish

Marine fish and shellfish

Inhalation

Milk

Dairy

Eggs

Beef

Pork

Poultry

Other meats

Vegetable fat

95% of Background Exposure From

Commercial Food Supply

Dioxin/PCB Exposure Trends

• Environmental Levels– Peaked in late ‟60s/early ‟70s – decline since

confirmed by sediment data

– Decline also supported by Emissions Inventory –shows significant decrease from ‟87 to „;95 (~80%)

• Human tissue data suggest mid-90s levels approximately half of 1980– 55 25 ppt TEQ lipid (~5ng/kg ww)

– Decrease continues

• Success of Regulatory Agenda

Dioxin TEQ Levels (PCDDs/PCDFs) in

U.S. Residents Have Fallen from 1960s

(Lorber, 2002)

Mean and Range of TEQs By Age Group

0

5

10

15

20

25

30

35

40

12-19 20-39 40-59 60+

Age Group (Number of Pools)

TE

Q

4.5

6.2

9.0

(17) (13) (10) (11)

13.7

10

6.6

23.5

19.3

15.8

34.4

25.6

41.7

12-19 20-39 40-59 60+

Age Group (years)

(Needham, 2005)

Adverse Effects

Wildlife and Domestic

Animals

Great Lakes fish, birds,

mammals

Baltic seals, Dolphins

Developmental/reproductiv

e effects

Immunological effects

Effects observed at

environmental levels

Cows, Horses, Sheep,

Chickens

Effects observed during

poisoning episodes

Laboratory Animals

Fish

Amphibians

Turtles

Birds

Rats

Mice

Guinea Pigs

Hamsters

Rabbits

Dogs

Non-human primates

Effects of Dioxins

BIOCHEMICAL

• Induction of Drug Metabolizing Genes– Cyp1A1/2, 1B1; GST;

UDPGT; ALDH…

• Induction of Proliferation Genes

• Induction of Cytokines– TNF, IL-6, IL-1β

• Induction of Oxidative Stress

• Induction of Growth factors/receptors– TGFs, EGFR…

• Modulation of Hormones/Receptors

TOXIC

• LethalityWasting

• Gonadal/Lymphoid Atrophy

• Hyperplasia/Metaplasia

• Endocrine Disruption

• Carcinogenicity

• Repro/Developmental toxicity

• Functional Devpt. Toxicity

• Dermal Toxicity

• Immunotoxicity

• Neurotoxicity

• Hepatic Toxicity

• Cardiovascular Toxicity

• Bone/Teeth Toxicity

Effects of Dioxins

• Multiple Effects

• Multiple Tissues

• Both Sexes

• Multiple Species

• Throughout

Vertebrata

• Molecular/

Biochemical

• Metabolic/ Cellular

• Tissue/Organ

• Growth/

Differentiation

• Wasting/Death

Dioxin Effects Require the “Ah

Receptor”

• Highly conserved protein

– throughout Vertebrates

– Related Proteins in Invertebrates

• Member of Growing Family of Key Regulatory

Proteins

– Development, Aging, Hypoxia, Daily Rhythms

• Necessary, but Not Sufficient, for All of the

Effects of Dioxins

DRE TATA

Altered gene expression

TCDD, ...

Co-activators

Co-repressors

Arn

t

hsp90

mRNA

Changes in protein levels

(e.g., CYPIA1, IL-1, ...)

Differentiation

and

Proliferation

Rb, RelA,…HIFa, Sim,...

chromatin

phosphorylation/

dephosphorylation

ClClCl ClO

O

ClClCl ClO

O

ClClCl ClO

O

ClClCl ClO

OArn

t

BT

Fs BT

Fs

hsp90AIP,..

Other Proteins

AIP,..hsp90

Mechanism of Action

Introduction Methods Results

PCNs

Summary

Dioxins‟ Effects in People

• Cardiovascular Disease

• Diabetes

• Cancer

• Porphyria

• Endometriosis

• Decreased Testosterone

• Chloracne

• Biochemical – Enzyme Induction

– Receptor Changes

• Developmental– Thyroid Status

– Immune Status

– Neurobehavior

– Cognition

– Dentition

– Reproductive Effects

– Altered Sex Ratio

– Delayed Breast Devpt

Unfortunate Poisoning Episodes

• PCBs/PCDFs – Japan (“Yusho”)

– Taiwan (“Yucheng”)

• PBBs/PBNs– Michigan

• TCDD– Seveso, Italy

– Vienna, Austria

– Ukraine

• Clear Evidence of Adverse Health Effects

Chloracne

Classic Toxic Effect

• “Hallmark of Dioxin Toxicity”

• High-Dose Response

• Genetic Polymorphism

• Occurs in People, Monkeys, Cows, Rabbits, and Mice

• Associated with multiple problems with skin, teeth, hair and nails following prenatal exposure

La exposición a

dioxinas genera

Cloroacné!

HEALTH EFFECTS IN “HIGHLY”

EXPOSED POPULATIONS

• Exposures Are Not As High As We

Once Thought:10-100X Background

(“Ambient”)

• Occupational Populations

– Chloracne, Cancer, Heart Disease,

Diabetes, ...

• Poisoning Episodes

– Chloracne. Cancer, Heart Disease,

Diabetes, Reproductive,

Developmental, Hormonal and Immune

Effects

EFFECTS SEEN IN ADULTS AT

BACKGROUND EXPOSURES

• Type II Diabetes

– Decreased Glucose Tolerance

– Hyperinsulinemia

– Mechanistic Plausibility

• Endometriosis

– Hormone Disruption and Immune Suppression

– Animal Models

• Cancer????

HEALTH OUTCOMES IN

PRENATALLY-EXPOSED CHILDREN

• Studies in the US (Michigan, North Carolina, Lake Oswego); Japan; the Netherlands; Sweden; Finland

• Low Birthweight

• Cognitive and Behavioral Impairment

• Immune System Effects

• Hormonal Changes (Thyroid Effects)

• Altered Dentition

Dioxin Effects of Greatest

Concern

• Developmental Alterations Occurring at “High End” of Background Population

• Decreased neuro-optimality and IQ

• Altered Behavior

• Altered Immune System

• Altered Hormone Systems

• Altered Growth

ORGANOFLUORINES

F is the most electronegative element. C-F bond

is the strongest of known covalent bonds.

e.g., C-F bond can withstand boiling with 100%

sulfuric acid without any defluorination.

Perfluorinated (fully fluorinated) alkanes are

anthropogenic.

O

C8F17 S - O-

O

PFOS: Perfluorooctanesulfonate

PFOS is the ultimate degradation product of

POSF-based compounds and the compound

found in the environment

-

STRUCTURES OF PERFLUORINATED

SURFACTANTS MONITORED (1)

ORGANOFLUORINE SURFACTANTS

Surfactants: Surface-active agents; due to selective

adsorption at the interface.

Amphiphilic or amphipathic : Implies attraction to two

different kinds of media. Surfactant structure consists

of ‘hydrophilic’ and ‘hydrophobic’ parts.

The hydrophobic portion repels not only water but also

oil and fat. So, fluorinated surfactants exhibit both

water and oil repellency when adsorbed on substrates

such as textiles or paper.

USES OF FLUORINATED

SURFACTANTS (1)

Adhesives, antifogging, antistatic agents, cement

and paint additives, insulators for cables,

electroplating, etching of glass, herbicides and

insecticides, cleaners for hard surfaces (automotive

waxes), cosmetics (hair conditioning formulations).

Fire-Fighting Foams: Formulated to float on

flammable liquids and extinguish flames. FS in

Aqueous Film-Forming Foams (AFFF) reduce the

surface tension of water and form a film on the

fuel surface.

USES OF FLUORINATED

SURFACTANTS (2)

Paper: Used in folding cartons for snack foods,

carry-out fast food, cake mixes, margarine, candy,

bakery products and pet foods.

Polishes, Waxes, Leather: In floor waxes to

provide dust repellency.

Textiles: Carpets, Polyester, etc. to impart soil, oil

and water repellency.

ANALYSIS

Ion-pair extraction (TBA/MTBE)

Betasil- C18 column separation

HPLC-ESMS/MS (triple quadrupole; ES-ve)

Hansen et al. 2001, ES&T, 35, 766-770

Further validation and improvement to accommodate variety of

species/tissues

Sample-Homogenize

: Florisil/carbon column

Location Ringed Gray Seal

Seal

Concentrations (ng/mL) of PFOS

in blood and sera of seals: Spatial differences

Values in brackets are mean; n = 10 to 50

Baltic Sea 16-475 [110] 14-76 [37]

Canadian Arctic <3-12 11-49 [28]

Norwegian Arctic 5-14 [9] NA

PFOS IN POLAR BEARS :

ALASKAN ARCTIC

Liver 82-680 [350] ng/g, wet wt

Blood <2-52 [34] ng/mL

Values in brackets are mean; n = 10 to 40

CONCENTRATIONS (ng/g, wet wt) OF

PFOS IN LIVERS OF COASTAL

AQUATIC MAMMALS

Bottlenose dolphin Florida <75-1520 [490]

Bottlenose dolphin Med.Sea <7-425 [54]

Harbor seal California <4-57 [27]

River dolphin India <35-81

Weddell seal Antarctica <35

Values in brackets are mean; n = 2 to 50

Species n conc.

Salmon andwhitefish liver

15 80

Mink liver 18 2630

Liver-BMF 33

BIOMAGNIFICATION OF PFOS IN MINK

(LIVERS)

Concentrations are in ng/g, wet wt.

ENVIRONMENTAL FATE

PFOS is relatively water soluble, low

vapor pressure and tends to bind to

particulates

While PFOS and related

perfluorinated alkanes are

persistent and can be accumulated

into and retained in biota, their

environmental fate processes are

fundamentally different from

organochlorines and paradigms and

models developed for OCs do not

apply

TOXIC EFFECTS OF PERFLUOROCHEMICALS

Peroxisome proliferation (interference with fatty acid binding and transport)

Mitochondrial bioenergetics (stimulation of mitochondrial respiration)

Inhibits cell-cell communication

Reproductive and developmental effects: rat LD50 = 250 mg/kg

Neuro-endocrinal effects

CONCLUSIONS

PFOS is a ubiquitous global environmental

pollutant: present both in urban and remote

locations. Distribution of PFOA, FOSA and PFHS

is localized.

PFOS bioaccumulates in humans and wildlife;

biomagnifies in the food chain.

Age or sex-related accumulation is not prominent

Transport pathways and environmental fate of

fluorochemicals are the subjects of further/current

investigation.