Spatial Variability of Flame Retardants in Indoor

Dust

Simona Jilková1, Lisa Melymuk1*, Šimon Vojta1, Pernilla

Bohlin-Nizzetto2, Martina Krátká1, Jana Klánová1

1 Research Centre for Toxic Compounds in the Environment (RECETOX)2 Norwegian Institute for Air Research (NILU)

Project goals

2

1. Assess sampling techniques in

indoor environments

2. Understand the distribution of

SVOCs in indoor environments

What sampling techniques

(air, dust, surface wipes)

are most effective for

different compound

classes?

How can we achieve a balance

between representativity, ease of

sampling and practicality in large

screening indoor studies?

What is the spatial variability in

compounds within a room?

Are the different indoor matrices

(air, dust, surface films) in

equilibrium or having some

defined relationship?

Can we predict air concentrations

from indirect sampling? E.g., from

concentrations in another target

matrix?

Sampling

• Active air sampling

(gas and particle

fractions,

particle-size

specific fractions)

• Passive air sampling

• Surface films/dusts:

windows wipes and

surface wipes

• Dusts: floor dusts

and bed dust

3

Dust variability

• Variability between

matrices (exposed vs.

hidden vs. bed) is 20-

65%

• Variability within

matrices is ~90-100%

4

IMPLICATION:

• Individual dust samples show localized effects and may

not be representative of average room conditions

• Homogenized dust samples are more representative.

05

1015202530

BDE28

BDE47

BDE66

BDE100

BDE99

BDE85

BDE154

BDE153

BDE183

BDE209

Conc. (n

g/g

)

Bed Bed

Exposed floor Exposed floor

Hidden floor Hidden floor

Predicting air concentrations from dust

• Weschler and Nazaroff, 2010 method

for predicting dust concentrations from air

Predicted air conc. =

(dust conc. x dust density)/(OM fraction x KOA)

5

Air concentrations predicted from dust

6

y = 0.32xR² = 0.99

(0.75)

0

0.005

0.01

0.015

0.02

0.025

0 0.05 0.1

Pre

dic

ted a

ir c

onc.

(pg

/m3)

Measured air conc. (pg/m3)

OCPs

y = 1.6xR² = 0.87

0

0.02

0.04

0.06

0.08

0.1

0 0.05 0.1

Pre

dic

ted a

ir c

onc.

(pg

/m3)

Measured air conc. (pg/m3)

PCBs

y = 0.078xR² = 0.62

0

0.1

0.2

0.3

0.4

0 2 4 6

Pre

dic

ted

air

conc.

(pg

/m3)

Measured air conc. (pg/m3)

PBDEs

0

2

4

6

8

10

0 50 100

Pre

dic

ted a

ir c

onc.

(pg/m

3)

Measured air conc. (pg/m3)

NFRs

Background and objectives

• Dust samples are frequently used indoors to (a) evaluate

presence and concentrations of flame retardants (FRs),

(b) identify sources, and/or (c) estimate human exposure

• A wide range of techniques are used to sample dust

(collection area, collection method, type of dust...) that

may not be comparable or representative.

• GOAL: assess the utility of dust for source

identification, for evaluating overall indoor

levels, and/or human exposure, and identify

what practices in dust collection are best suited

for different study goals.

7

Sampling techniques

• Wipe sampling

– Pre-cleaned kimwipes, wetted

with isopropyl alcohol

– Wiped over surfaces until no

more visible dust on wipe

– Number of wipes per sample

depended on “dirtiness” of

surface

– Surface area recorded

• Vacuum sampling

– Polyester vacuum socks

inserted at front of vacuum hose

– Surface area and dust mass

recorded

8

Study locations

• 3 rooms

– 1 residential (open concept

living room/dining room/

kitchen)

– 1 seminar room (classroom

with ~60 person capacity)

– 1 computer room (teaching

computer room with ~60

person capacity)

9

Room layouts

Flat

Seminar

room

Computer

room

10

Target compounds

19 halogenated FRs

• TBP-AE

• TBP-BAE

• TBP-DBPE

• TBX

• PBEB

• PBT

• HBB

• DBHCTD

• EH-TBB

• BEH-TEBP

• BTBPE

• syn-, anti-DDC-CO

• DDC-CO-MA

• DBDPE

• α-, β-,γ-, δ-DBE-DBCH

• α-, β-TBCO

• PBBZ

• TBCT

• PBBA

10 PBDE congeners

• BDE 28

• BDE 47

• BDE 66

• BDE 85

• BDE 99

• BDE 100

• BDE 153

• BDE 154

• BDE 183

• BDE 209

17 organophosphate FRs

• TIBP

• TNBP

• TCEP

• TCIPP

• DBPP

• BDPP

• TDCIPP

• TPHP

• EHDPP

• TBOEP

• CDP

• TEHP

• o-, m-, p-TMPP

• TIPPP

• TDMPP

• TDBPP

• TBPP

11

(Abbreviations from

Bergman et al. 2012)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%PBBATBCTPBBZb-TBCOa-TBCOg,d-DBE-DBCHb-DBE-DBCHa-DBE-DBCHDBDPEBEH-TEBPa-DDC-COs-DDC-COBTBPEEH-TBBDBHCTDHBBTBP-DBPEPBTPBEBDDC-CO-MATBXTBP-BAETBP-AE

HFRs - detection

Not detected:

TBX, DDC-CO-MA,

α- and β-TBCO,

TBCT, PBBA

Low levels:

TBP-AE, TBP-BAE,

PBEB, PBT, TBP-

DBPE, DBHCTD

Consistent detection, high levels:

α-, β-, γ- and δ-DBE-DBCH, DBDPE,

BEH-TEBP, syn- and anti-DDC-CO,

BTBPE, EH-TBB, HBB, PBBZ

12

Flat, wipes Flat,

dust

Sem

inar

rm,

dust

Sem

inar

rm,

wip

e

Com

p.

rm,

dust Computer rm,

wipes

OPFRs - detection

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100% TBPP

TDBPP

TDMPP

TIPPP

p-TMPP

m-TMPP

o-TMPP

TEHP

CDP

TBOEP

EHDPP

TPHP

TDCIPP

BDPP

DBPP

TCIPP

TCEP

TNBP

TIBP

All OPFRs

detected in flat, 14

of 19 detected in

seminar and

computer rooms

Low levels (always <5% of

ΣOPFRs): TIBP, TCEP, DBPP,

BDPP, TDCIPP, EHDPP,

TEHP, o-TMPP, p-TMPP, p-

TMPP, TIPPP, TDMPP,

TDBPP, TBPP

Consistent detection, high

levels:

TNBP, TPHP, TBOEP, CDP, and

especially TCIPP (avg. 70% of

ΣOPFRs)

13

Flat, wipes Flat,

dust

Sem

inar

rm,

wip

e

Com

p.

rm,

dust Computer rm,

wipes

Sem

inar

rm,

dust

Summary of overall concentrations – floor dust

• What flame retardants are in average floor dust?

0

5000

10000

15000

20000

25000

30000

35000

40000

Flat Seminar room Computerroom

Av

g.

flo

or

du

st

co

nc.

(ng

/g)

OPFRs

HFRs

PBDEs

“Signal” of FRs dominated by OPFRs

0

5000

10000

15000

20000

25000

30000

35000

40000

Flat Seminarroom

Computerroom

Av

g.

flo

or

du

st

co

nc.

(ng

/g)

Other PBDEs

Other HFRs

Other OPFRs

DBDPE

TDCIPP

DDC-CO

TNBP

TCEP

BEH-TEBP

TPHP

EHDPP

BDE 209

CDP

TCIPP

TBOEP

Compounds with avg. >50 ng/g

14

Summary of overall concentrations – surface wipes

• What flame retardants are on average surfaces?

0

1000

2000

3000

4000

5000

6000

Flat Seminarroom

Computerroom

Av

g.

wip

e c

on

c.

(ng

/m2)

OPFRs

HFRs

PBDEs

0

1000

2000

3000

4000

5000

6000

Flat Seminar room Computer room

Av

g.

wip

e c

on

c.

(ng

/m2)

Other PBDEs

Other HFRs

Other OPFRs

TBOEP

ΣTMPP

ΣDBE-DBCH

TPHP

BDE 209

TNBP

BEH-TEBP

CDP

TCIPP

•“Signal” of FRs dominated by OPFRs

• Higher conc. in flat due to choice of

surfaces – locations that are not often

cleaned therefore have large dust mass per

unit area

Compounds with avg. >10 ng/m2

15

IN MORE DETAIL...

• PBDEs - link to sources in flat

• NFR source identification

• OPFR source identification

• Concentrations by mass vs. area

• Implications for sampling technique, future

work

16

PBDEs – floor dust – by mass

Ranging over 3 orders of magnitude

Σ10PBDEs: 3.55 – 1382 ng/g

10PBDEs in floor dust

Flat

Sem

inar

room

Com

pute

r roo

m

0

500

1000

1500

Con

c.

(ng

/g)

9PBDEs in floor dust

Flat

Sem

inar

room

Com

pute

r roo

m

0

10

20

30

40

Co

nc.

(ng

/g)

BDE-209 - floor dust

Flat

Sem

inar

room

Com

pute

r roo

m

0

500

1000

1500

Co

nc.

(ng

/g)

Concentrations, spatial

differences driven by BDE-209

17

Floor dust - PBDE Congener Distributions

Relatively consistent congener

profiles in seminar room and

computer room, >95% BDE-209

More variability

in all congeners,

and particularly

in BDE-209

•BDE-209

ranged from

78-98% of

ΣPBDEs

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Seminar room Computerroom

Flat

BDE 183

BDE 153

BDE 154

BDE 85

BDE 99

BDE 100

BDE 66

BDE 47

BDE 28

Fraction BDE-209

18

BDE-209 distribution – relationship to sources

• BDE-209 source in electronics?

y = -0.05x + 1.03R² = 0.72

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Fra

cti

on

of

BD

E-2

09

Distance from TV unit (m)

Contribution of BDE-209 to

Σ10PBDEs in floor dust decreases

with distance from TV unit

- Suggests electronics as source?

y = 0.01x + 0.61R² = 0.02

0

0.2

0.4

0.6

0.8

1

0 2 4 6

Fra

cti

on

of

BD

E-2

09

Distance from TV unit (m)

No such distribution observed in wipe samples

More variation in contribution of BDE-209

(87-97% in floor dust but 26-87% in wipes)

- Differences in sources to dust and surfaces?

- More or less mixing in one matrix than another?

19

Floor dust

Surface wipes

Computer room vs. seminar room – BDE-209

• Same building materials, different room equipment

• Differences due to computers?

010203040506070

Seminarroom

Computerroom

Seminarroom

Computerroom

Floor dust Surfaces

BD

E-2

09

co

nc.

(ng

/m2)

0200400600800

10001200

Seminar room Computerroom

Floor dustBD

E-2

09

co

nc. (n

g/g

)

• Or just because the computer room is more dusty?

0

20

40

60

Du

st lo

ad

ing

(m

g/m

2)

Dust surfaceloading

Avg. per room

20

Computer room vs. seminar room – other FRs

• If we see differences by mass and area, suggests

electronics as source...

0

0.5

1

1.5

2

Seminarroom

Computerroom

Seminarroom

Computerroom

Floor dust Surfaces

Conc.

(ng/m

2)

TIPPP

0

2

4

6

8

10

12

14

Seminarroom

Computerroom

Seminarroom

Computerroom

Floor dust Surfaces

Conc.

(ng/m

2)

TDCIPP

0

0.5

1

1.5

2

2.5

3

3.5

Seminarroom

Computerroom

Seminarroom

Computerroom

Floor dust Surfaces

Conc.

(ng/m

2)

TEHP

• But, in floor dust by mass, none of these compounds have a statistically

significant difference between seminar room and computer room

21

Computer room vs. seminar room – other FRs

0

500

1000

1500

2000

2500

3000

3500

4000

Seminarroom

Computerroom

Seminarroom

Computerroom

Floor dust Surfaces

Conc.

(pg/m

2)

HBB

HBB is only FR with significant difference

between seminar room and computer

room.

Suggests electronics as source to

computer room.

No other FRs have a significant difference

in concentrations between computer room

and seminar room.

0

50

100

150

200

Seminar room avg. Computer room avg.

Conc.

(ng/g

)

HBBWhat hinders our ability to identify

differences?

• Complex influences on observed

concentrations: source differences, but

also differences in dust loading, room

use

22

PBDEs – floor dust – area vs. mass

By mass: ranging over 3 orders of

magnitude

Σ10PBDEs: 3.55 – 1382 ng/g

By area: ranging over 4 orders of

magnitude

Σ10PBDEs: 0.04 – 82.1 ng/m2

10PBDEs in floor dust

Flat

Sem

inar

room

Com

pute

r roo

m

0

20

40

60

80

100

Co

nc.

(ng

/m2)

10PBDEs in floor dust

Flat

Sem

inar

room

Com

pute

r roo

m

0

500

1000

1500

Con

c.

(ng/g

)

- Potential source-related differences apparent in ng/g, but not by ng/m2

- Confounding factor of variable dust surface loading obscures source

differences

23

Σ10PBDEs in floor dust – ng/g Σ10PBDEs in floor dust – ng/m2

Spatial variability in flat

24

Concentration

[ng/m2]

<0.1

0.1-0.5

0.5-1

1-5

5-10

10-50

50-100

100-500

ΣPBDEs

Concentration

[ng/m2]

0.5-1

1-5

5-10

10-50

50-100

100-500

500-1000

ΣNFRs

Spatial variability in lecture rooms

25

Concentration

[ng/m2]

1-5

5-10

10-50

50-100

ΣNFRs in

computer

room

ΣNFRs in

seminar room

Concentration

[ng/m2]

0.05-0.1

0.1-0.5

0.5-1

1-5

5-10

10-50

Implications for sampling – example – HFRs in floor dust

26

Averages

0

100

200

300

400

500

600

700

800

Seminar room avg Computer avg Flat avg

Conc.

(ng/g

)

PBBZ DBE-DBCH

DBDPE BEH-TEBP

DDC-CO BTBPE

EH-TBB DBHCTD

HBB TBP-DBPE

PBT TBP-BAE

TBP-AE

0

200

400

600

800

1000

1200

1400

1600

Seminar rm -low

Seminar rm -high

Computer rm -low

Computer rm -high

Flat - low Flat - high

Conc.

(ng/g

)

Highest and lowest conc.• Up to 1400x difference in

concentrations of HFRs within a given

room

• Typically individual HFRs range 6x

within 1 room

• Comparable to the range observed

between rooms

27

0

200

400

600

800

1000

1200

1400

1600

Seminar rm -low

Seminar rm -high

Computer rm- low

Computer rm- high

Flat - low Flat - high

Conc.

(ng/g

)

PBBZ

DBE-DBCH

DBDPE

BEH-TEBP

DDC-CO

BTBPE

EH-TBB

DBHCTD

HBB

TBP-DBPE

PBT

TBP-BAE

TBP-AE

Key challenges

• Different concentrations and compound profiles

are obtained from different areas in a room and

sample types – what is representative?

• When using surface wipe sampling on horizontal

surfaces, how to include influence of dust

loading per surface?

• What metric is most important for exposure –

ng/m2 or ng/g? – e.g., for child dust ingestion

28

Acknowledgements

• Sampling assistance: Roman Prokeš

• Financial support from Czech Ministry of Education

(LM2011028 and LO1214), the European Social Fund

and state budget of the Czech Republic (projects

"Employment of Best Young Scientists for International

Cooperation Empowerment” CZ.1.07/2.3.00/30.0037 and

"Employment of Newly Graduated Doctors of Science for

Scientific Excellence" CZ.1.07/2.3.00/30.009).

29

30

Lisa Melymuk

Research Centre for Toxic Compounds in the Environment

Masaryk University, Brno, Czech Republic

melymuk@recetox.muni.cz

Full compound list - HFRs

• TBP-AE – allyl 2,4,6-tribromophenyl ether (ATE)

• TBP-BAE - 2-bromoallyl-2,4,6-tribromophenyl ether (BATE)

• TBP-DBPE - 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE)

• TBX - 2,3,5,6-tetrabromo-p-xylene (pTBX)

• PBEB – pentabromoethylbenzene

• PBT - pentabromotoluene

• HBB – hexabromobenzene (HBBZ)

• DBHCTD - hexachlorocyclopentenyl-dibromocyclooctane (HCDBCO)

• EH-TBB - 2-ethylhexyl-2,3,4,5-tetrabromobenzoate

• BEH-TEBP - bis(2-ethlyhexyl)tetrabromophthalate (BEHTBP)

• BTBPE - 1,2-bis(2,4,6-tribromophenoxy)ethane

• syn-, anti-DDC-CO - Dechlorane Plus (DP)

• DDC-CO-MA – Dechlorane Plus mono adduct (DPMA)

• DBDPE – decabromodiphenylethane

• α-, β-,γ-, δ-DBE-DBCH – tetrabromoethylcyclohexane (TBECH)

• α-, β-TBCO - 1,2,5,6-tetrabromocyclooctane

• PBBZ - 1,2,3,4,5-pentabromobenzene

• TBCT - 3,4,5,6-tetrabromo-2-chlorotoluene

• PBBA - pentabromobenzyl acrylate

31

Full compound list - OPFRs

• TIBP - tri-iso-butyl-phosphate

• TNBP - tri-n-butylphosphate

• TCEP - tris (2-chloroethyl) phosphate

• TCIPP - tris (1-chloro-2-propyl) phosphate (TCPP)

• DBPP - dibutylphenylphosphate

• BDPP - butyldiphenylphosphate

• TDCIPP - tris (1,3-dichloro-2-propyl) phosphate (TDCPP)

• TPHP - tri-phenyl phosphate

• EHDPP - 2-ethylhexyl diphenyl phosphate (2EHDPP)

• TBOEP - tris(2-butoxyethyl) phosphate (TBEP)

• CDP - cresyl diphenyl phosphate

• TEHP - tris(2-ethylhexyl)phosphate

• o-, m-, p-TMPP – tritolyl phosphate (ToTP, TmTP, TpTP)

• TIPPP - tris(2-isopropylphenyl)phosphate

• TDMPP - tris(3,5-dimethylphenyl)phosphate

• TDBPP - tris(2,3-dibromopropyl)phosphate

• TBPP - tris(4-tert-butylphenyl) phosphate (TpTBPP)

32

Full analytical methods

• Prior to extraction, all samples were spiked with known amounts of recovery standards [8 13C12-

BDEs, 13C18-triphenyl phosphate, 13C-DBDPE, 13C-HBB, 13C-BTBPE, 13C-aDP, 13C-sDP, 13C-

PBBZ]. Kimwipes were extracted with 250 ml of dichloromethane using automated warm Soxhlet

extraction (Büchi B-811, Switzerland). Extracts were then concentrated to cca 2 ml and divided

into aliquotes. For analysis of PBDEs and other FRs, 70 % of the extract was cleaned-up using 5

g of H2SO4-modified silica column and eluted with 20 ml of dichloromethane. For analysis of

OPFRs, 30 % of the extract underwent non-destructive clean-up on non-modified activated silica

(5 g) column, topped with 1-2 cm of Na2SO4 and eluted with 20 ml of dichloromethane:acetone 3:7

(v:v). Both eluents were concentrated under gentle stream of N2 to final volume (50 µl for

destructive part and 1 ml for non-destructive part) and spiked with internal standard (13C12-BDE-

77).

• PBDEs and other FRs were analyzed on GC/HRMS consisting of Agilent 7890A GC coupled to

Autospec Premier MS (Waters, Micromass, UK), equipped with 15 m x 0.25 mm x 0.10 µm Rtx-

1614 (Restek, USA) capillary column. The MS was operated in EI+ SIM mode at the resolution

>10000. For BDE-209, the resolution was set to >5000. One µl of sample was injected in splitless

mode, using He as a carrier gas with initial constant flow of 1 ml/min, which changed to 1.4 ml/min

after 14th minute (PBDEs). For PBDEs inlet, GC/MS interface and ion source temperatures were

280, 280°C and 250 °C respectively. GC temperature programme was as follows: 80 °C (1 min

hold), then 20 °C/min to 250 °C, 1.5 °C/min 260 °C (2 min hold) and finally 25 °C/min to 320 °C

(4.5 min hold). For other FRs, inlet temperature was 250 °C and oven temperature programme

was: 80 °C (1 min hold), then 30 °C/min to 140 °C, 4°C/min to 175 °C, 8 °C/min to 270 and finally

15 °C/min to 325 °C (5 min hold).

33

FRs in electronics – wipes from electronic surfaces

BDE-209?

• What fraction of conc. in wipes is reflecting components in electronics and what

from air/other dust in room?

BEH-TEBP, DBE-DBCH,

HBB, BTBPE?TCIPP, CDP?

0

2

4

6

8

10

12

14

16

Conc.

(ng/u

nit)

TBP-AE TBP-BAE TBP-DBPE

PBEB PBT HBB

DBHCTD EH-TBB BEH-TEBP

BTBPE ΣDDC-CO DBDPE

ΣDBE-DBCH PBBZ

0

2

4

6

8

10

12

Conc.

(ng/u

nit)

BDE 28 BDE 47 BDE 66

BDE 85 BDE 99 BDE 100

BDE 153 BDE 154 BDE 183

BDE 209

0

100

200

300

400

500

600

700

800

Conc.

(ng/u

nit)

TIBP TNBP TCEP TCIPP DBPP

BDPP TDCIPP TPHP EHDPP TBOEP

CDP TEHP ΣTMPP TIPPP TDMPP

TDBPP TBPP

34

HFRs in floor dust

35

OPFRs in floor dust

36

BFRs in floor dust – by area

37

HFRs in wipes

38

Conc. in flat dominate due to dusty surfaces.

HFRs in wipes – excluding surfaces with long dust accumulation

39

OPFRs in wipes

All surfaces:

Excluding those with long dust accumulation:

40