Organohalogen concentrations and a gross and histologic ...

Briefly, ∑PCBs is the sum (s) of the concentrations of the 51 individual or coeluting
congeners (if detected): CB # 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. ∑DDTs is the sum of 4,4’-DDT, 4,4’-DDD and 4,4’-
DDE. ∑HCHs is the sum of the α-, β- and γ-hexachlorocyclohexane. ∑CHLs is
the sum of oxychlordane, trans-chlordane, cis-chlordane, trans-nonachlor, cisnonachlor
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
BDPEs (n=80) were determined by electron capture negative ion (low resolution)
MS using an external standard. Briefly, ∑PBDEs is the sum (s) of the
concentrations of the 35 individual or co-eluting congeners (if detected): BDE#
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).
Statistics
The statistical analyses were performed with the SAS statistical software
package (SAS V8 and enterprise guide V1) and a significance level of p=0.05
was used. The contaminant data were log-transformed (base e) prior to the
analyses in order to meet the assumption of normality and homogeneity of
the variance, while BMD showed no deviation from normality (Shapiro-
Wilk test).
Histology in relation to age, sex, protein casts and season
The relationship between grades of histopathological changes (mild, moderate
and severe, respectively) and age was tested within a one-way ANOVA
(age as dependent variable and histopathological change as independent).
When significant differences were found these were tested among each
other by Tukey’s post hoc test. Then, the prevalence of grades of histopathology
between males and females was tested within a X 2
-test on categorised
age groups (subadults, adults and old, respectively). The relationship between
grades of histology, season (Oct-Mar vs. Apr-Sept) and medullary hyaline
casts, respectively, was tested within a X 2
-test.
Histology and contaminants
The relationship between each group of contaminants (PCBs, DDTs, CHLs,
dieldrin, HCHs, HCB and PBDEs, respectively) and histology (mild, moderate
and severe) was tested within a two-way ANOVA (contaminant group
as dependent variable and age/sex group and histology as class variables)
with 1 st order interaction links (age/sex group*histological changes). The
principle in the further datahandling was a successively reduction of nonsignificant
interactions, judged from the type-III sum of squares (p>0.05),
after which the significance of each of the remaining factors was evaluated
from the final model (LSMean). When significant differences was found
between age/sex groups (subadults, adult females and adult males, respectively)
in the model, these were tested among each other by Tukey’s post hoc
test.
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