Environmental fate of brominated flame retardants · brominated flame retardants Martin Kohler1), Peter Schmid1), Paul C. Hartmann2), Michael Sturm2), Norbert V. Heeb1), Markus Zennegg1),

Martin Kohler ● AQUAbase Workshop on Risk Assessment of Organic Micro Pollutants in the Aquatic Environment ● Aachen 2006

Environmental fate of brominated

flame retardants

Martin Kohler1), Peter Schmid1), Paul C. Hartmann2), Michael Sturm2), Norbert V. Heeb1), Markus Zennegg1), Andreas C. Gerecke1), Erika Gujer1),

Hans-Peter E. Kohler2), and Walter Giger2)

1) Empa, Swiss Federal Laboratories for Materials Testing and Research2)Swiss Federal Institute of Aquatic Science and Technology (Eawag)


Outline

Introductionbrominated flame retardants properties and pathways into the environment

PBDE polybrominated diphenyl ethersbrominated diphenylethers in fish from Swiss lakesatmospheric transport

DecaBDE decabromo diphenyletherrapidly increasing levels in sewage sludge and sedimentssecondary poisoning?

HBCD hexabromocyclododecanesproperties and stereochemistryincreasing environmental concentrations and selective enrichment

Summarytake home messages


Introductionbrominated flame retardants

properties and pathways into the environment


Brominated flame retardants (BFR)

Properties of BFRBFR reduce the flammability of combustible materialsBFR are second most important additives for plastics (300,000 t/a)PBDE, HBCD and TBBPA are endocrine disrupting chemicalsPBDE: thyroid axis (T3, T4), (anti) estrogenic, anti androgenic, AhR interaction, EROD activity increase, delay of puberty, suppression ventral prostate growth. HBCD: T4/TTR competition. TBBPA: estrogenic

Hamers, T., Tox. Sci. 2006, 92(1), 157

OBrx Bry

PBDE

Br

Br

BrBr

Br

Br

HBCDBr

OH

Br

OH

Br

Br

TBBPA


How do BFR emerge?

Production(3 major manufacturers)

OEC

D /

In

dust

ryVo

lunt

ary

mea

sure

s fo

r th

e re

duct

ion

of e

mis

sion

s ar

e im

plem

ente

d

emissions

Processing(downstream users)

emissions

Products(plastics, textiles)

emissions

Disposal(dumping / incineration / recycling)

emissions


How do BFR emerge?Brominated flame retardants

... are barely water soluble (µg/l-ng/l)

... have a low vapor pressure (µPa)

how are they released?

Possible mechanismsevaporation upon production and downstream use, e.g. upon contact with hot polymers

degradation / ageing of polymers -dust particles are released and transported via the atmosphere and sewage

direct abrasion from materials and particle-bound transport

direct evaporation from materials and gaseous transport

brittle foam ...


BFR are present in the environment

BFR in WhitefishWhitefish from 8 Swiss lakes, 10 fish samples pooled from each lakePentaBDE and HBCD are present at the 100 ng/g lw levelConcentrations are still below total PCB concentrations

M. Zennegg, M. Kohler, A. C. Gerecke, P. Schmid, Chemosphere, 2003, 51, 545-553


PentaBDEbrominated diphenylethers in fish from Swiss lakes

atmospheric transport


Technical PBDE products

PentaBDE mix OctaBDE mix DecaBDE

- PentaBDE ≈ 5 Br atoms - OctaBDE ≈ 8 Br atoms - DecaBDE = 10 Br atoms- typical congener: BDE-47 - typical congener: BDE-183 - pure BDE-209- mixture of Tri-HexaBDEs - mixture of Hexa-NonaBDEs - traces of Nona/OctaBDEs- banned in EU in 2004 - banned in EU in 2004- persistent chemical - endocrine disruptor- developmental toxicity- endocrine disruptor Congener distribution in technical PBDE products

O

Br

BrBr

Br

BDE-47

O

Br Br

Br

Br

Br

Br

Br

BDE-183

O

Br Br Br Br

BrBr

Br

Br

Br

Br

BDE-209

Br3

[%]Br4

[%]Br5

[%]Br6

[%]Br7

[%]Br8

[%]Br9

[%]Br10

[%]Penta-BDE 0-1 24-38 50-62 4-8 - - - -Octa-BDE - - - 10-12 43-44 31-35 9-11 0-1Deca-BDE - - - - - - 0.3-3 97-98


PBDE in Swiss whitefish

0

10

20

30

40

50

60

70

80

90

100

Lake Greifen Lake Biel Lake Lucerne Lake Zürich LakeNeuchatel

LakeConstance

Lake Geneva Lake Thun

Con

cent

ratio

n [n

g/g

lw] (

lw: l

ipid

wei

ght)

BDE-28

BDE-47

BDE-99

BDE-100

BDE-153

BDE-154

BDE-183

Bars labeled from left (BDE-28) to right (BDE-183)

3 Br

4 Br

6 Br

7 Br

5 Br

O

Br Br

2

45

6

PBDE

3

2'

3'

4'6'5'

x y

M. Zennegg, M. Kohler, A. C. Gerecke, P. Schmid P. Chemosphere 2003, 51, 545


PBDE in Swiss whitefish – sources?

r2 = 0.70

0

10

20

30

40

50

60

70

80

20 40 60 80 100 120 140 160 180PBDE in whitefish [ng/g lw]

lake

sur

face

/ la

ke v

olum

e [k

m-1

]

Lake

Thu

n

Lake

Gen

eva

Lake

Con

stan

ce

Lake

Neu

chat

el

Lake

Zür

ich

Lake

Luc

erne

Lake

Bie

l

Lake

Gre

ifenPBDE travel through the atmosphere

O

Br Br

2

45

6

PBDE

3

2'

3'

4'6'5'

x y

VAcPBDE ~

PBDE levels correlate to surface /volume ratio of lake

M. Zennegg, M. Kohler, A. C. Gerecke, P. Schmid P. Chemosphere 2003, 51, 545


DecaBDErapidly increasing levels in sewage sludge and

sedimentssecondary poisoning?


BFR - rapidly increasing concentrationsInventories of DecaBDEare increasing

Sewage sludgeDecaBDE concentrations increased by 500% within 10 years (8 STPs in Switzerland)

Lake sedimentsDecaBDE is the major PBDE in sediments of Lake Greifen and concentrations are increasing since the late 1970s

PBDE in Swiss sewage sludge 1993 and 2002

M. Kohler, M. Zennegg, A. C. Gerecke, P. Schmid and N. V. Heeb, Organohalogen Comp. 2003, 61, 123-126

M. Kohler, M. Zennegg, P. C. Hartmann, M. Sturm, E. Gujer, P. Schmid, A. C. Gerecke, N. V. Heeb, H.-P. Kohler, and W. Giger,15th Annual Meeting of SETAC Europe, Lille, France, May 22-26, 2005.


BFR - secondary poisoning?

DecaBDE replaces Penta- and OctaBDE products, banned by the EUDecaBDE debromination: are there critical secondary products?Is DecaBDE a safe alternative to Penta- and OctaBDE?

EU risk assessment DecaBDEConclusion (i)There is a need for further information and/or testingSecondary poisoning:degradation to more toxic and bioaccumulative compounds

lower brominated diphenylethers

formation of endocrine disruptorssimilar to PentaBDE and OctaBDE?

-Brx

?


BFR - secondary poisoning?

DecaBDE debrominationTransformation in sewage sludge

2 NonaBDE and 6 OctaBDEdetected upon anaerobic degradation in sewage sludge (30% turnover in 238 days)

Other dehalogenation processesphotochemical transformationabiotic reduction processes

Are debromination products present in the environment?

A. C. Gerecke, P. C. Hartmann, N. V. Heeb, H.-P. Kohler, W. Giger, P. Schmid, M. Zennegg, M. Kohler, Anaerobic Degradation of Decabromodiphenyl Ether, Environmental Science & Technology, 2005, 39, 1078-10834

A. C. Gerecke, W. Giger, P. C. Hartmann, N. V. Heeb, H.-P. E. Kohler, P. Schmid, M. Zennegg, M. Kohler, Anaerobic degradation of brominatedflame retardants in sewage sludge, Chemosphere, 2006, 64, 311-17

Investigate lake sediments


HBCDproperties and stereochemistry

increasing environmental concentrations andselective enrichment


HBCD – an overviewProperties of HBCD

C12H18Br6 Mw: 641.73 major isomers (α-, β-, γ-HBCD)Six stereocentersThermally labile, degradation above 170-200 oCHighly lipophilic (log Kow = 5.6)Low vapor pressure (4.7 x 10-7 mm Hg)Low water solubility (α, β, γ-HBCD: 48.4, 14.7, 2.08 µg/l)

Production figures for HBCD16,700 t per year, minor contributor to total market for BFRImportant product on the EU-market (32% of BFR)

Typical application for HBCDAdditive flame retardant in polystyrene foam (insulation panels)


Complex stereochemistry of HBCD

Synthesis of HBCD from cyclododecatriene


HBCD stereoisomers16 HBCD stereoisomers are theoretically possible


HBCD stereoisomersStereoisomers

6 pairs of enantiomers4 meso forms

Assignment of HBCD structures

selective crystallizationpure γ-HBCD

purification of mother liquid by column chromatographypure α and β-HBCD

chromatography on chiralphase (HPLC)pure enantiomers

x-ray diffraction analysisassignment to structure

α β

γ δ/ε

δ/ε

N. V. Heeb, W. Bernd Schweizer, M. Kohler, A. C. Gerecke, Chemosphere 2005, 61, 65-73.


α-HBCD is a persistent substanceHBCD – an emerging pollutant

The α-HBCD isomer is persistent (minor compound in the technical product, dominated by γ-HBCD). A strong enrichment of this isomer in whitefish wasobserved

The stereochemistry of HBCD was determined. This was an important step for the EU risk assessment of this chemical

R

S

R

S

S

S

A. C. Gerecke, M. Kohler, M. Zennegg, P. Schmid, and N. V. Heeb, Organohalogen Comp., 2003, 61, 155-158.N. V. Heeb, W. Bernd Schweizer, M. Kohler, A. C. Gerecke, Chemosphere 2005, 61, 65-73.R. J. Law, M. Kohler, N. V. Heeb, A. C. Gerecke, P. Schmid, S. Voorspoels, A. Covaci, G. Becher, K. Janák, C. Thomsen,Environmental Science & Technology, 2005, 39(13), 281A - 287A (A-pages article and cover page of ES&T of July 1, 2006)


HBCD is present in sediments

HBCD, a brominated flame retardant, is present in sediment of Greifensee

HBCD appeared in the late 1980s (one decade later than the PBDE) and increase with time

HBCD levels (2.5 ng/g dw) are currently about 4 times below the levels of DecaBDE but at similar levels as PentaBDE

HBCDs were also detected inwhitefish from Greifensee:100 ng/g lipid-based,α-HBCD isomer only

2001

1995

1989

1982

1974

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1970 1980 1990 2000

Year

Tota

l HB

CD

s in

lake

sed

imen

t [ng

/g d

ry w

eigh

t] BrBr

Br

BrBr

Br

***

*

* *

M. Kohler , P. Schmid , P.C. Hartmann , M. Sturm , N.V. Heeb , M. Zennegg , A.C. Gerecke , E. Gujer , H.-P. E. Kohler , W. Giger,16th Annual Meeting of SETAC Europe, The Hague, The Netherlands, May 7-11, 2006.


HBCD levels Europe, Asia and America

HBCD market demand and levels in air and biota

highest market demand in Europehighest concentrations in air and dolphins in Europeconcentrations of HBCD follow local market demand

BFR Americas Europe Asia Rest of world all RegionsTBBPA 18,000 11,600 89,400 600 119,600HBCD 2,800 9,500 3,900 500 16,700DBDE 24,500 7,600 23,000 1,050 56,150OBDE 1,500 610 1,500 180 3,790PentaBDE 7,100 150 150 100 7,500Total PBDEs 33,100 8,360 24,650 1,330 67,440Total 53,900 29,460 117,950 2,430 203,740Data from BSEF, Bromine Science and Environmental Forum, 2001 (www.bsef.com)

A. Covaci, A. C. Gerecke, R. J. Law, S. Voorspoels, M. Kohler, N. V. Heeb, H. Leslie, C. R. Allchin, J. de Boer, Hexabromocyclododecanes (HBCDs) in the environment and humans - a review, Environmental Science & Technology, 2006, 40, 3679-3688


Take home messages

BFR (300'000 t/y) are second most important plastic additivesand potential endocrine disruptors

There is little knowledge on how BFR are getting in the environment

PentaBDE and OctaBDE were banned in the EU in 2004. They are subjected to bioaccumulation and atmospheric transport

DecaBDE inventories in sediments are rapidly increasing

Relevance of secondary poisoning by formation of PentaBDE/OctaBDE type lower brominated BDEs not know, yet

HBCD represents a BFR with a complex stereochemistry

There is evidence for substancial persistence and bioaccumulation of the α-HBCD isomers


Thank you

Andreas C. Gerecke (Empa)Christian Bogdal (Empa)Cornelia Seiler (Empa)Daniela Wenger (Empa)Erika Gujer (Empa)Heinz Vonmont (Empa)Markus Zennegg (Empa)Norbert V. Heeb (Empa)Oliver Nagel (Empa)Peter Schmid (Empa)Regula Haag (Empa)Renato Figi (Empa)Saverio Iozza (Empa)

Bernd W. Schweizer (ETHZ)Konrad Hungerbühler (ETHZ) Martin Scheringer (ETHZ)

Alfred Lück (Eawag)Anja Liedtke (Eawag)Christiane Vögeli (Eawag)Erwin Grieder (Eawag)Etienne Vermeirssen (Eawag)Hans-Peter Kohler (Eawag)Michael Sturm (Eawag)Paul Hartmann (Eawag)Rik Eggen (Eawag)Thomas Kupper (Eawag)Walter Giger (Eawag)

Anna Sobek (FAL Reckenholz)Thomas Bucheli (FAL Reckenholz)

Hans-Rudolf Buser (ACW Wädenswil)Marianne E. Balmer (ACW Wädenswil)Markus D. Müller (ACW Wädenswil)Thomas Poiger (ACW Wädenswil)

Daniel Bernet (Uni Bern)David Bittner (Uni Bern)Helmut Segner (Uni Bern)

Daniel Scheidegger (Kanton Bern)Markus Zeh (Kanton Bern)Ueli Ochsenbein (Kanton Bern)Seepolizei Thunersee (Kanton Bern)

Documents

Environmental fate of brominated flame retardants · brominated flame retardants Martin Kohler1), Peter Schmid1), Paul C. Hartmann2), Michael Sturm2), Norbert V. Heeb1), Markus Zennegg1),