Distribution of Chlorinated Hydrocarbon Pesticides and PCBs in the ...

N.W.Q.L. continuous large volume extractor and analysed by
N.Q.W.L. in Burlington. The 1986 results indicated reasonable
agreement between labs despite differences in timing location and
analytical methods.
A more rigorous intercalibration was undertaken in June
1987. Triplicate snow samples (3 x 200L, 5 x 40L samples in
teflon bags) were collected by Arctic Labs upon arrival at the
Ice Island on 6 June and returned to Resolute Bay for extraction*
Snow (3 x 150-300L in a cleaned aluminum melting tank and 40L
teflon bags) was collected from the same depth and general
location by Arctic Labs on 8, 9, and 15 June, melted and eluted
through XAD-2 columns in the Ice Island field lab. Columns were
extracted and analysed in the Seakem labs in Sidney, B.C.
The results of this intercalibration, given in ~ppendix C
and summarised in Table 3.9., indicate reasonable agreement*
Mean concentrations generally within one standard deviation for
most of the compounds of interest except alpha endosulphan. The
mean percentage difference of Arctic Labs from NWQL data for
eleven compounds detected by both labs was 94% (103% excluding
alpha endosulphan).
An additional snow intercalibration for the HCHs was done
in June 1987 with Greg Patton of U.S.C. who collected 15-20L
samples in an cleaned aluminum tank, thawed the sample in the Ice
Island field lab. The melted snow sample (2-3L) was aspirated
through a filter (Gelman 47mm binderless glass fiber) and a pair
of bonded n-octyl silica gel cartridges (J.T.Baker C8-SPE) in
series and the cartridge sealed in a vial, and later extracted
and analysed at U.S.C. Due to the smaller sample size only *he
HCHs were detected and the results of these analyses and the
individual sample HCH values found by Arctic Labs and N.W. Q - L=
are compared in Table 3.10. The mean HCH values are comparable
but considerable variation is evident between individual samples
for these compounds. The ratio of alpha to gamma is lower for
the Arctic Labs data compared to the other laboratories.