Organohalogen concentrations and a gross and histologic ...

182
quantification approach used for PCBs and OCs in the adipose tissues was
based on peak area of the GC-µECD response, which is described in detail in
Dietz et al., (2004). Briefly, PCBs is the sum (Σ) of the concentrations of the 51
individual or co-eluting congeners (if detected): PCB # 31/28, 52, 49, 44, 42,
64/71, 74, 70, 66/95, 60, 101/84, 99, 97, 87, 110, 151, 149, 118, 146, 153, 105,
141, 179, 138, 158, 129/178, 182/187, 183, 128, 174, 177, 171/ 202/156, 200,
172, 180, 170/190, 201, 203/196, 195, 194, 206. Σ-DDTs is the sum of 4,4’-
DDT, 4,4’-DDD and 4,4’-DDE. Σ-HCHs is the sum of the α-, β- and λhexachlorocyclohexane.
Σ-CHLs is the sum of oxychlordane, transchlordane,
cis-chlordane, trans-nonachlor, cis-nonachlor and heptachlor epoxide.
Contaminant fractions were subsequently sent to the National Water
Research Institute (Environment Canada, Burlington, Ontario, Canada L7R
4A6 (NWRI)) for determination of brominated diphenyl ether (PBDE) flame
retardants.
PBDEs, non-ortho PCBs and PCDD/Fs
BDPEs were determined by electron capture negative ion (low resolution)
MS using an external standard. Briefly, PBDEs is the sum (Σ) of the concentrations
of the 35 individual or co-eluting congeners (if detected): PBDE# 10,
7, 11, 8, 12/13, 15, 30, 32, 28/33, 35, 37, 75, 71, 66, 47, 49, 77, 100, 119, 99, 116,
85, 155/126, 105, 154, 153, 140, 138, 166, 183, 181, 190. Gas chromatographic
conditions for the PBDEs were described by Luross et al. (2002).
Extraction and analysis of PCDD/Fs in polar bear fat was conducted by
Axys Analytical Services (Sidney, BC, Canada) used previously described
techniques with only minor modification (U.S. EPA, 1998, 1999). Fat samples
were homogenized with Na2SO4 and spiked with mixture of 13Clabelled
non-ortho PCBs, as well as PCDDs (2,3,7,8-TCDD, 1,2,3,7,8pentaCDD,
1,2,3,4,7,8-hexaCDD, 1,2,3,4,7,8-hexaCDD, 1,2,3,6,7,8-hexaCDD,
1,2,3,7,8,9-hexaCDD, 1,2,3,4,6,7,8-heptaCDD, and OCDD) and PCDF isomers
(2,3,7,8-TCDF, 1,2,3,7,8-pentaCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-hexaCDF,
1,2,3,6,7,8-hexaCDF, 1,2,3,7,8,9-hexaCDF, 2,3,4,6,7,8-hexaCDF, 1,2,3,4,6,7,8heptaCDF,
1,2,3,4,7,8,9-heptaCDF, and OCDF) surrogate standards to
monitor extraction efficiency. Samples were extracted in toluene via Soxhlet
and concentrated. Extracts were cleaned-up and PCDD/Fs were isolated
through a series of chromatographic columns (U.S. EPA 1998). Analysis was
performed using a high-resolution mass spectrometer coupled to a highresolution
gas chromatograph (HRGC-HRMS) equipped with a DB?5 capillary
chromatography column (60 m ´ 0.25 mm i.d. ´ 0.1 µm film thickness;
J&W Scientific, Folsom, CA, USA). A second column, DB-225 (30 m ´ 0.25
mm i.d. ´ 0.15 µm film thickness), was used for confirmation of 2,3,7,8tetraCDF.
All analytical procedures were carried out according to protocols
as described U.S. EPA (1998).
Statistical analyses
Excel 97 ® was employed as spreadsheet and SAS (1990) in calculations of
means and confidence intervals of reproductive organ measurements and
BMD. A one-tailed one-sample t-test was used to determine the significance
(p