# Rapport till Naturvårdsverket för projektet “Analys av polybromerade difenyletrar (PBDE) och

hexabromcyklododekan (HBCDD) i human mjölk från Stockholm – en tidstrends studie [Dnr 721-2653-05Mm]

Britta Fängström, Anna Strid och Åke Bergman Institutionen för miljökemi , Stockholms universitet

Stockholm 2005-11-23

# Temporal trends of brominated flame retardants in milk from Stockholm mothers, 1980-2004

Britta Fängström , Anna Strid and Åke Bergm a n

Departm e nt of Environmental Chem istry, Stockholm Universit y, SE-106 91 Stockholm, Sweden;



## Summary
The objective of the present st udy was to assess the tem poral trends of polybrom inated diphenyl eth e rs (PBDEs), includ ing d ecaBDE , and hexabromocyclododecane (HBCDD) in
mothers m ilk from the Stockholm area. The pooled sam p les were covering the tim e period 1980 to 2004, with em phasis on sam p les from the last ten years. The temporal trend of PBDEs must be expressed on a congener basis since the developm ent of t h e individual PBDE congener concentrations differ. BDE-47, -99 and -100 concentrations reached a peak in the

m i d 1990’s and are now clearly showing d ecreasing levels. BDE-153 concentrations
increased un til y ear 2000 and thereafter the concen trations m a y level off but it is yet n o t clear
how the concentration s of this PBDE congener will develop over the n e xt few years

. It is no t possible to quantify decaBDE (BDE-209) in the hum a n m ilk. This m a y be due to poor
transfer to the m ilk lipids but m o st likely it is a result of the short half -life of this com p ound in
hum a n blood. HBCDD concentratio ns are 2004, approxim a tely four tim es the concentration
in 1980 sho w ing an increasing tem p oral trend un til the early 2000’s. It is too early to judge if the levels are decreasing or leveling off. Th e HBCDD conce n trations are in a rang e b e tween BDE-47 and BDE-99 and BDE-100.

1

## Backgr o und

The environm ental contam ination of polybrom in ated diphenyl ethers (P BDEs) were first reported in f i sh from Sweden in the early 1980’s ( 1 ), subsequently in Japan ( 2 ) and in hum a n

m ilk from Germ any in 1988 ( 3 ). These initial studies have been followed by num e rous studies
worldwide in hum a ns, fish, birds and m a mm als ( 4,5 ). Extensive summ ari e s on hum an PBDE exposure are given in re cent reviews, includi ng those by e.g. Hites ( 4 ), Sjödin et al ( 6 ) and Ryan ( 7 ).

Swedish hum an m ilk, from Stockholm, have been shown to contain increasing concentrations
of PBDEs fr om the early 1970s to 1997 ( 8 ), while sam p les from 1997 to 2000 indicated a decrease ( 9 ). The observed decrease was m a inly due to a reduction of BDE-47 concentrations
in the m ilk. A decrease of PBDE concentration s in Swedish m ilk has also been indicated by Lind and co-workers 2003 ( 10 ). In N o rway, PBDE concentrations in hum an m ilk increased
from 1986 to 2001 ( 11 ), within a s i m ilar conce n tra tion r a nge as reported in Sweden and in Japan ( 8-10,12 ). These tem poral tren d studies all i ndicate decreasing PBDE concentrations,
all d r iven by decreasing BDE-47 concentratio n s . Recently s e veral re ports have indicated increasing concentration of BDE-153, at concentr ations sim i lar or even higher than B D E-47 ( 13-16 ). In the United States, the PBDE concentr ations are approxim a tely 20 tim es higher in
hum a n subjects, com p aring m ean or m e dian leve ls, than those hitherto reported in Europeans ( 4,17 ).

Hexabrom ocyclododecane (HBCDD) has recently been reported at highly varying concentrations (ranging from 0.09 to 10.4 ng/g lipids) in m ilk fr om m o ther’s from Uppsala, Göteborg, Lund and Lycksele ( 18 ). HBC DD has also been re ported in hum a n m ilk from Norway but at slightly lower concentrat ions, ranging from 0.25 to 2.0 ng/g lipids ( 19 ).

The aim s of the present study were: to extend previous studies of PBDEs in pooled hum a n m ilk sam p les from Stockholm to cover the period 1980 to 2004 to indicate any tem poral c oncentratio ns changes o f PBDE congeners and o f HBCDD
to determ ine any potential tem poral tre nds of decabrom odiphenyl ether (BDE-209)
to add inform ation on PBDE ti m e trend in hum a n m ilk from Sweden

2

### Further thes e concentrations were co mpared to previous studies for PBDEs perform e d in pooled human m ilk from Sweden.



## Materi al and M e thods
Samples: Milk was collected from he althy native Sw edish m o thers by the Mothers m i lk centre in Stockholm. Milk samples are purchased from t h e centre and banked annually. Fourteen

m ilk sa m p les were taken out from 1980 to 2004 fo r analysis (c.f. Table 1 for the years). The

com positions of the pools were prepared to be as com p arable as possible, with 55-80% of the

m ilk from mothers nursing their first infant. Equal am ounts of m ilk fr om individual mothers

were m i xed, from the years 1980, 1984/85, 1988-2002, 2003 and 2004, representing m ilk
from 116, 102, 20, 15 and 20 m o thers respectively. The average age of the m o thers was 27-28 years in 1980 and 1984/85, and between 29-31 years in 1988-2004.

Chemicals: The individual PBDE congeners (num bered according to Ballschm iter et al. ( 20 )): BDE-47, BDE-77, BDE-99, BDE-100, BDE-1 53 were synthesized in-house ( 21 ). H BCDD was purchased from Ca mbridge Isotope La boratory and BDE-209 from Fluka Chemie,
Switzer land. All solven ts were of pro analysis quality. 2-Propanol from AnalaR (BDH laboratory supplies pool, England) and m e thyl te rt -butyl ether (HPLC-grade; Rathburn, Walkerburn, Scotland) were glass-distilled prior to us e. Silica gel (<0.063 mm) was purchased from Merck (Darm s tadt, Germ any) and activated (300°C, 12 h) before use.

Instruments: The PBDE analysis was perform e d by gas chrom a tography/m a ss spectrom etry (GC/MS) using a Finnigan TSQ 700 instrum e nt (Therm oFinnigan, Brem en, Germ any) connected to a Varian 3400 ga s chrom a tograph equipped with an AS200S CTC autosam p ler.
The transfer line tem p erature was set to 290°C and the ion source tem p erature m a intained at 200°C. Injections were m a de using a septum -equipped tem p erature programm able injector (SPI) fitted with a high perform a nce insert directly connect ed to a DB-5 HT capillary colum n (15 m x 0.25 mm i.d., 0.1 μm fil m thickness; J&W Scientific) with helium as carrier gas at a head pressure of 3 psi. The injector tem p erature was programmed from 60°C to 320°C at
150°C/m i n a nd the oven from 80°C ( 1 m i n), 15°C/ m i n to 300°C (16 m i n). The PBDE

congeners w e re analysed with selected ion m onitoring (SIM) by scanning for the negative
brom ide ion (isotopes m / z 79 and 81) for m ed by electron capture reactions at chem ical ionization (ECNI) with m e thane (5.0, AGA, Sto c kholm
, Sweden) as the electron

3

### therm a lization buffer gas at 5.6 torr and a prim ary electron energy of 70 eV. All
chrom a tographic data were collected, analys ed and quantified using the p r oprie tary ICIS2
software from Ther m o fi nnigan. The linear relati o n ship of the GC/MS system was dete rm ined and the quantifications w e re performed using a single point external standard within the concentration range of the linear relationship.

Extraction and cleanup procedure: The extraction and clean up procedure for the m ilk

sam p les is a modified version of a method for serum analysis first de scribed and validated by Hovander and co-workers ( 22 ). In the m odified version of the m e thod, form ic acid and diethyl
ether are used instead of hydrochloric acid and m e thyl tert -butyl ether ( 13 ). Surrogate standard, B D E-77 was added to the sam p les prior to extraction. In short, for m ic acid (1 m l ) and 2-propanol (6 m l ) were added to a m ilk sa mple (5 g), subsequently extracted with a

m i xture of n-hexane/diethyl ethe r (1 :1, 6 m l ), and re-ex t ra cted once (3 m l ). The lipid co ntent was determ ined gravim etrically after gentle evap oration of the solvent. The bulk of lipids was

rem oved with concentrated sulfuric acid a nd th e s a m p les were pooled 2 x 5 g. Additio nal cleanup was perform e d on two subsequently ap plied sulfuric acid/ silica gel colum n s, accord ing to Hovander et al. ( 22 ). Finally the sa mple was f r action a ted o n a colum n of activated silica gel (0.7 g). Most of the PCB congener and m a jor traditional organochlorine pesticide interferences were eluted w ith hexa n e (3 m l ) and th e PBDEs were elu t ed with hexane:DCM (1:1, 8 m l ). The solvent in the PBDE fraction were changed to hexane and
reduced to 50-100 μ l bef o re GC/MS analys is. All sam p le s we re protected from daylight during handling and storage to prevent any phot ochem i cal degradation of the brom inated

com pounds to be analyzed.

Recovery experiment: A recovery study for the PB DE conge ners, BDE-47, BDE-99, BDE100, BDE-153 and BDE-209 was perform e d on 5g of co w milk with a lipid content at 3% to validate the recovery of the m e thod at two different spike levels (0.1 ng/sample and 1 ng/sam p le) ( 13 ).

Analysis: Four PBDE congeners, BDE-47, BDE- 99, BDE-100, BDE-153 and BDE-209 were analysed with GC/MS (ECNI), as specified a bove, were quantified in the duplicate sam p les (A/B) with a total sam p le volum e at 10g with the SS, BDE-77.

4Table 1. Concentrations of PBDE congeners(in ng/g lipid and pmol/glipid) in pooled human milksamples from Sweden, 1980-2004ÅrBDE-47BDE-99BDE-100BDE-153HBCDDng/g lipidpmol/g lipidng/g lipidpmol/g lipidng/g lipidpmol/g lipidng/g lipidpmol/g lipidng/g lipidpmol/g lipid19800.120.250.0600.110.0440.0780.0370.0580.0840.1319840.260.530.0430.0760.0730.130.0820.130.0960.1519880.571.20.260.460.160.290.240.380.240.381990a (Pool 1)0.551.10.240.420.170.300.170.260.220.341990a (Pool 2)1.02.10.621.10.280.490.280.440.200.3119921.42.90.480.840.310.550.480.750.290.4419941.73.60.841.50.310.540.450.700.380.5919952.14.30.751.30.510.900.671.00.510.8019962.04.00.741.30.430.770.530.820.330.5219971.63.30.691.20.360.640.651.00.290.4519992.14.40.530.940.290.520.821.30.370.5720011.83.60.571.00.631.11.32.00.540.8320021.42.90.330.590.270.480.721.10.600.9320031.22.50.290.510.310.551.11.80.490.7720040.931.90.260.470.290.510.921.40.390.60a) Two different pools from the same year, Pool 1; n=20, meanage = 30, 65% of the mothers nursing their first infant,Pool 2; n=20, mean age = 29, 55% of the mothers nursing their first infant.

### Solvent blank sam p les representing every 5 sam p le were cleaned up and analyzed in the sam e way as the o t her sam p les

. Lim it of quantif ica ti on (LOQ) for the PBDEs were defined in direct
relation to the am ount of in terference of PBDEs in the blank samples. The PBDE concentrations in the sample had to be three tim es higher than the PBDE am ount in the blank to be considered as a quantif iable. T h e average blank sam p le am ount has been subtracted
f r om the res u lts. Labo ratory ref e ren c e m a terial w a s run in pa r a lle l to the a n alyzed s a mples.
The overall recoveries and st andard deviation (S D) of th e surrogate standards were
84% S.D. 5.5 for BDE-77.



## Results

The PBDE c ongener concentrations, run as dupli cate sam p les (A/B), are presented in Table 1. The data presented are the “m ean” value of the tw o analysis in the pooled m ilk sa m p les from
1980 to 2004. The concentrations of decabrom odiphenyl eth e r were low, above lim it of detection (L OD) but below the quantificati on lim it (LOQ), ranging from 0.01 to 0.10 pm ol/g lipid. Da ta o n HBCDD concentr ation s are a l so presented in T a ble 1. The concentratio ns are given both on a lipid weight basis (ng/g) a nd on a molar basis (pm o l/g) to prom ote direct

com p arison between analytes s i nce there are su b s tantial d i f f

e rences in m o lecular weig ht between the analytes.



## Discussion
This study stresses the results from previ ous studies on PBDE in hum an milk from
Stockholm
, where the concentratio ns of the lower brom inated PBDEs are decreasing from the

m i ddle of 1990’s, after increas ing concentrations were observed in m ilk from the 1970-1980’s
to the m i d 1990’s. The PBDE concentrations in the pooled hum a n m ilk sa mples in the present study are in close agreem ent with concentrations reported in previous studies on human m ilk
from Swede n ( 8-10 ). To som e extend the sam e pools were used in the present study as in previous studies by Meironyté and co-workers ( 8,9 ) and the agreem ent between the s t udies is good although the extraction m e thod, standards, an alytical instrum e ntation and tim e for the analyses d i ffer.

51. 0 2. 0 3. 0 4. 0 5. 0

19 75 19 80 1 9 8 5 1 9 9 0 1 9 9 5 20 0 0 2005pmol/glipids 

### BD E-47 BDE-153

0. 5 1. 0 1. 5 2. 0 2. 5

19 75 19 80 19 85 19 9 0 19 95 20 00 20 05pmol/glipids



### HBCDD

0. 2 0. 4 0. 6 0. 8 1. 0

1 9 7 5 1 9 8 0 1985 1 990 1 9 9 5 2 0 0 0 200 5pmol/glipids 1. 0 2. 0 3. 0 4. 0 5. 0

19 75 19 80 1 9 8 5 1 9 9 0 1 9 9 5 20 0 0 2005pmol/glipids 

### BD E-47

1. 0 2. 0 3. 0 4. 0 5. 0

19 75 19 80 1 9 8 5 1 9 9 0 1 9 9 5 20 0 0 2005pmol/glipids 

### BD E-47 BDE-153

0. 5 1. 0 1. 5 2. 0 2. 5

19 75 19 80 19 85 19 9 0 19 95 20 00 20 05pmol/glipids 

### BDE-153

0. 5 1. 0 1. 5 2. 0 2. 5

19 75 19 80 19 85 19 9 0 19 95 20 00 20 05pmol/glipids



### HBCDD

0. 2 0. 4 0. 6 0. 8 1. 0

1 9 7 5 1 9 8 0 1985 1 990 1 9 9 5 2 0 0 0 200 5pmol/glipids 

### HBCDD

0. 2 0. 4 0. 6 0. 8 1. 0

1 9 7 5 1 9 8 0 1985 1 990 1 9 9 5 2 0 0 0 200 5pmol/glipids

Figure 1. BD E-47, BDE-1 53 and HBCDD concentrati ons in pm ol/g lipids i n po oled m ilk sam p les from Sweden 198 0 to 200 4

.



### From the m i ddle of 1990’s the concentrations of the lower brom inated PBDE congeners, i.e. BDE-47, BDE-99 and BDE-100, are decreasing, wh ile the concentrations of BDE-153 are increasing (Table 1, Figure 1). This is in acco rdance to indications from previous studies perform e d in hum a n m ilk from Swe d en were the influence of BDE-153 have increase and BDE-47 have decreased ( 8,9 ). The ratio of BDE-153/BDE-47 (ng/g lipids) in 1980 to 2004 is changed from 30 % to 99 %.

It is not possible to see any tim e tren d f o r BDE-209 in the m ilk sam p les due to low an d
sim ilar concentrations over the tim e period, all below LOQ (0.01-0.10 pmol/g lipid). Hum a n

m ilk m i ght not be as good indicator m a trix for BDE-209 as it has been proved to be for other organohalogen substances (OHS). The short ha lf-life of BDE-209 in hum a n blood (15 days) ( 23 ) m a y strongly influence the concentrations al so in the m i lk even though we do not know the half-life of this PBDE congener in hum a n m ilk. Further, we do not know how efficient the
transfer of BDE-209 is to the m ilk. We m a y specula te that the transfer is less efficient than for
the lower brom inated diphenyl ethers since a pr evious study on paired samples of hum an m ilk and blood plasm a where the BDE-153/BDE-47 ratio is lower in m ilk compare to blood, 28% and 67% respectively ( 24 ). This difference betw een m ilk and blood for BDE-153 has also

6

### been seen in Norway, wher e the relative am ount of BDE- 153 is lower in breast m ilk

com p ared to serum ( 16 ). Therefore serum see m s to be a m o re suitable m a trix for assessing
hum a n exposure to higher brom in ated diphenyl ethers i.e. thos e with six brom ines or more. Concentration of up to 3.4 pm ol/g lipid weight have been reported for BDE-209 in Faroese
mother’s m ilk ( 13 ) confirm i ng that this com pound can be transferred to the m ilk.

Despite the differences between m ilk and blood there is obviously a change in PBDE congener pattern over tim e , w ith increasing BD E-153 and decreasing B D E-47 concentrations. Higher concentrations of BDE-153 com p ared to BDE-47 has been seen in hum a ns from the U.S.A., Norway, The Netherlands and the Faroe Islands ( 13-16,25 ). The reason f o r th is is s t ill not explained but could possibly be due to a higher persisten ce of BDE-153 than of BDE-47. Possibly the change is influenced by the fact that PBDE products con t ain i ng the lower
brom inated diphenyl ethers (PentaBDE and Octa BDE) are phased out. It is too early to
dism iss the hypothesis of BDE-153 being form e d abiotically or via m e tabolismfrom BDE209. Im portantly, the present study can not conf ir m a decrease of BDE-153 in hum an m ilk
from Stockholm

.

The tim e trend for HBCDD in the Stockholm hum a n m ilk shows a lim ited increase over tim e (Figure 1 ) . The presen t situa tion is u n certain with no clear evidence of a decreasing tendency.
From 1980 t h e concentrations has increased fr om 0.13 pm ol/g lipid to 0.60 pm ol/g lipid in 2004 (Table 1). During the last 10 years the c oncentrations have varied between 0.60 and 0.93

pm ol/g lipid. These concentra tions are in a sim ilar range as BDE-99, BDE-100 and BDE-153 and even higher during the last few years than for BDE-99 and BDE-100. The result shows
that HBCDD are transferred to the m ilk. In a recently reported study on regional differences
of PBDEs in hum a n m ilk from Swede n, sim ilar HBCDD concentrations w e re reported, ranging from 0.09 to 10.4 ng/g lipid ( 18 ).

When pooled sam p les are analyzed no individual variation is taken into account, therefore the

com position of the pools are very important. All pool s were prepared to be as com p arable as possible e.g. with 55-80 % of the m ilk com i ng fr om m o thers nursing their first infant. In the beginning of the 1980s the num ber of m o thers in each pool w a s about 100 , thereafter from 1988 to 2004 only 15-20 m o thers are included in each pool. T h e averag e age of the m o thers is 27-31 years. Despite these rath er similar requirem ents in the pools there are differences between the pools which m i ght have an influe nce on the trend e.g. pool S1 and S2 from 1990

7

### (Table 1). However to be able to m a ke tim e tr end studies it is alm o st necessary to use pooled

sam p les to m i ni m i ze number of sa mples to be an alyzed. To m a ke the results as reliab l e as possible duplicate analyses were perf orm e d of the pools, control sam p les and blank samples has been run in parallel throughout the whol e analysis. The m e thod used for the PBDE analysis in hum a n m ilk has previously been used for PBDEs a nd PCB analysis ( 13,26 ) and is

a m odified m e thod for OHS analysis in hum an s e rum ( 22 ). A recovery study was perfor m ed
with cow’s m ilk (3% fat content) and th e overall recovery for BDE-47, BDE-99, BDE-100
and BDE-153 were about 90% w ithin a range of 79-107% ( 13 ).



## Acknowledgement
This study was financially supported by th e Swedish EPA and Stockholm University.

References

(1) Andersson, Ö.; Blom kvist, G. Pol y brom inated aro m atic pollutants f ound in fish i n Sweden. Chemosphere 198 1, 10
, 1 0 51-10 60. (2) Watanabe, I.; Kashim oto, T.; Tatsukawa, R. Pol y bro m inated biph eny l ethers in marine fish, shellfish and river and m a r i ne sedi m ents in Japan. Chemosphere 1987, 16
, 2 389- 2396

. (3) Kruger, C., Pol y brom ierte Biphen y le un d Pol ybrom ierte Biphen y lether-Nachweis und Bestimmung in ausgewählten Lebensm i ttel, West fälischen Wilhelms Universität zu Munster Germany , 19 88. (4) Hites, R. A. Pol y brom inated dip h en y l et hers in the environm ent and in peo p le: A m e taanaly s is of concentrations. Environ. Sci. Technol. 2 004 , 38
, 94 5-95 6. (5) Law, R. J.; A l aee, M.; Allc hin, C. R.; Boon, J. P.; Lebeuf, M.; Lepom
, P.; Stern, G. A. Levels and trends of pol y b r o m i nated diphen y lethers and othe r brom inated flam e retardants in wildlife. Environ. Int. 2 0 03, 29, 757- 770

. (6) Sjödin, A.; P a tterson, D. G. Jr.; Berg man, Å. A review on hum an exposure to brom inated flam e r e tardants (BFRs) - particularly po l y brom inated dip h en y l et hers (PBDEs). Environ. Int. 2003 , 29
, 82 9

- 839. (7) Ry an, J. J., Poly brom inate d dipheny l ethe rs (PBDEs) in hum an m i lk; occurrence worldwide, The Third Int ernational W o rkshop on B r ominated Fl ame Retardants 200 4 , 17. (8) Meiron y t é, D.; Norén, K.; Berg m a n, Å. Analy s is of p o l y brom inated dip h en y l et hers in Swedish human m ilk. A ti me-rel a ted trend stud y, 1 9 7 2 -199 7. Jour nal of Toxicol ogy and Environmental Health, Part A 1999 , 58
, 329-3 41. (9) Meiron y t é Guvenius, D. a nd Norén, K., Po l y br om inared diphen y l ethers in Swedish hum an milk. The foll ow-up stud y, The Second I n ternational Workshop on Brominated F l ame Retardants 1- 1-200 1 , 3 03. (10) Lind, Y.; Darnerud, P. O.; Atu m a, S.; Aune, M.; Becker, W.; Bjerselius, R.; Cnattingius, S.; Gly n n, A. Pol ybrom inated dipheny l ethers in breast milk from Uppsala county
, Sweden. Environ. Res. 200 3, 93
, 1 8 6 -194. (11) Thom sen, C., Froshaug, M ., Leksnes, H., and Becher, G., Brom inat ed fla m e ret a r d ants in breast m ilk fr om Nor w ay , Organohal og en Compoun ds 200 3
, 60 -65 , 33. (12) Akutsu, K.; Kitagawa, M. ; Nakaza wa, H.; Makino, T.; Iwazaki, K.; Oda, H.; Hori, S. Tim e

trend (1973-2000) of pol ybro m i nat e d dipheny l ethers in Japanese mother' s m ilk. Chemosphere 2003 , 53
, 64 5

- 654.



### 8(13) Fängström , B.; Strid, A.; G r andjean, P.; We ihe, P.; Bergman, Å. A retrospective study of PBDEs and PCBs in hum an m ilk fro m the Faroe Islands. Environmental Health: A global Acces s sci enc e source 2005, 4:1 2

. (14) Fängström , B

. ; Hovander, L.; Bignert, A.; Athanassi adis, I.; Linde rholm
, L.; Gr andjean, P.; Weihe, P.; Bergman, Å. Concentrations of PBDE, PCB and OH-PCBs in seru m from pregnant Faroese wo men and their children seven y ears later. Environ. Sci. T echnol. 20 05

. (15) Johnson-Restrepo, B.; Kannan, K.; Rapaport, D.; Rod a n, B. Pol y br om inated dip h en y l ethers and pol y c hlor inated biphen y ls i n hum an adipose tissue from New York. Environ. Sci. Technol. 2 005 , 39
, 51 77-5 182. (16) Thom sen, C., Liane, V., Froshaug, M., a nd Becher, G., Levels of brom inat ed flame ret a rdants in hum an sa m p l es fro m N o rway through three decades, Organoha logen Compo unds 2 005
, 658. (17) Schecter, A.; Pavuk, M.; P ä pke, O.; Ry a n , J. J.; Birnb a u m , L.; Rosen, R. Pol y br om inated diphen y l ethers (PBDEs) in U.S. m o thers' milk. Environ. Health Perspect. 2003, 111
, 17 23- 1729

. (18) Lignell, S., G l ynn, A., Darnerud, P. O., Aune , M., Bergdahl, I., Bar r egård, L., an d Bensry d
, I., Regional diff erences in levels of persistent or ganic pollutants in bre ast m ilk fro m prim apa r a
wo m e n in Uppsala. Göteborg, Lun d and Ly cksele (Sweden), 200 5

. (19) Thom sen, C., Froshaug, M ., Broadwell, S., Becher, G., and Eggesbo, M., Levels of brom inated fl am e retardant s in m ilk from the Norwegian hum an milk study : H U MIS, Organohal og en Compoun ds 200 5 , 5 09. (20) Ballsch m i ter, K.; Mennel, A.; Buy t en , J. Long chain alk y l-pol y s ilo xanes as non-polar stationary phases in capill ary gas chromatography. Fresenius J. Anal. Chem. 1993 , 34 6, 396

- 402. (21) Marsh, G.; Hu, J.; Jakobsson, E.; Rahm , S.; Bergman, Å. Synthesis and character ization of 32 pol y b r o m i nated diphen y l ethers. Environ. Sci. Technol. 19 99, 33, 3033- 303 7. (22) Hovander, L.; Athanasiadou, M.; Asplund, L.; Jensen, S.; Klasson Wehler, E. Extraction and cleanup methods for anal ysis of phenoli c and neutral organohalo gens in plasma. J. Anal. Toxicol. 2 0 00, 24, 696- 703

. (23) Thuresson, K.; Höglun d, P

. ; Hag m ar, L.; Sjödin
, A.; Berg m a n, Å.; Jakobsson, K. Apparent half-lives of hepta- to decabrom i nat e d di pheny l ethers in hum ans as deter m ined in occupationally exposed wo rkers. Environ. Health Perspect. 2005, Submitted May 2005

. (24) Meiron y t é Guvenius, D.; Aronsson, A.; Ek m a n-Ordeberg, G.; Bergman, Å.; Norén, K. Human prenatal and postnatal exposure to polybrom i na ted diphen y l ethers, pol y c hl orina t ed biphen y ls, pol y c hlor obi phen y lols an d pentachlorop h enol. Environ. Health Perspect. 2003, 1 11, 1 235- 1241

. (25) Weiss, J., Me ijer, L., Sauer, P., Linder hol m , L., Athanassiadis, I., a nd Bergm a n, Å., PBDE and HBCDD levels in bloo d from Dutch m o thers and infants - Analy s is of a Dutc h Groningen infant cohort, Organoha lo gen Compou nds 20 04
, 66
, 267 7. (26) Weiss, J.; Pä pke, O.; Bignert, A.; Jense n, S.; Gre y erz, E.; Agostoni, C.; Besana, R.; Riva, E.; Giovannini, M.; Zetterström , R. Concentrations of di oxins and oth e r organochlo r ines (PCBs, DDTs, HCHs) in hum an milk from Seveso, Mila n and a Lom b ardia n rural area in Italy : a study performed 25 y ears after the heavy dio x in exp o s ure in Seveso. Acta Paedi a tr. 200 3, 92
, 467-4 72.



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