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

cleaned. Samples were collected on 8 cm. x 11 cm. teflon
reinforced glass fibre (May, 1986, solvent rinsed) or cellulose
(August, 1986, soxhlet extracted with acetone) filters. Flow
rates were measured and recorded on a clock driven rotating card
recorder which also provided a record of the length of the
sampling period.
Air samples were collected for a period of from 30 to 52 h
at a flow rate of from 1.62 to 1.67 m3*min-l. During operation,
the sampler was approached from the downwind direction and, when
necessary, the power generator relocated to be downwind of the
sampler. At the end of the sampling period, the filter was
folded using solvent clean tongs so as to retain collected
particulates. It was found necessary to do this while the filter
remained in the sampler with the pump in operation to avoid loss
of the filter due to the wind. The filters were stored in
prebaked aluminum foil pouches and were stored frozen.
2.8.2 Va~our Phase ~am~linq
Two independent but similar systems, the Arctic Labs High
Volume Sampler (AHVS) and Terry Bidleman High Volume Sampler
(TBHVS) were used to collect vapour phase chlorinated organics.
Both employed polyurethane foam plugs to retain the sample, but
differed in mechanical details.
The results of the 1986 air sampling with the AHVS
indicated that some channeling around the front polyurethane plug
had occured, presumably due to shrinkage during sampling.
Subsequently , in 1987 a redesigned one piece f ilter/plug holder
was used similar to that used in the TBHVS air sampler.
The AHVS is shown in Figure 2.2 and consisted of a 142 mm
stainless steel filter unit, a pair of poly-urethane foam plugs
(15 cm x 7.8 cm) in a holder, a calibrated flowmeter and high
capacity oil-less vane pump (Gast, 270 L/minute) driven by a
brushless motor. The sampler was situated 4 m up wind of the air
pump and was approached from down wind when in use.