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

Instrumental calibration was compared by exchange and
analysis of GC/ECD calibration standards. The results (Table 3.6)
indicate good agreement between labs for these compounds with no
systematic differences. Four polyurethane plug extracts were
exchanged after initial analysis: the results (Table 3.7)
indicate reasonable agreement between labs for the limited number
of compounds compared.
Air samples were collected simultaneously in August 1986
and June 1987 by Arctic Labs and U.S.C. then analysed -
independantly as part of the intercalibration excersise and
accuracy check. The mean values and standard deviations during
each sampling trip for the two labs are compared in Table 3.8
for those compounds reported by both laboratories. The results
are generally comparable and means are within two standard
deviations, although HCB and alpha-HCH in August 1986 show
greater differences. The low 1986 value found by Arctic Labs is
believed due to breakthrough as a result of the channelling
arround the front plug. The air sampler modification in 1987
minimised this tendancy and consequently the 1987 concentration
values are more comparable. For all compounds the average
difference of means for AL compared to USC were 77% and 102% for
1986 and 1987 respectively.
d ) Snow Samples
Snow sampling and analyses were intercalibrated
+ with
Denis Gregor of Surveys and Interpretation Division, Water
Quality Branch, Inland Waters Directorate, Environment Canada
with analytical support by the National Water Quality Lab
(N. W. Q. L) , Burlington, Ontario. Initial comparison was done with
a snow sample collected by Denis Gregor from adjacent to the air
strip in early May 1986 three weeks prior to the Arctic Labs
samples, collected from a remote site. The snow sample was
collected, transported and allowed to melt in solvent cleaned 40L
FEP teflon bags. The melted snow was dichloromethane extracted
without filtration in the field lab in Resolute Bay using a