Specifications

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4.2.7 Strategy
The sampling strategy using passive dosimeter, Miran and Medigas 3010 was chosen since there
would be at least one personal and one environmental sample per delivery to a maximum of two
personal samples and one environmental sample for each delivery. The Medigas and passive
dosimeter badges are personal samples and their data can be compared to the WCB OF BC
exposure limits. The Miran was an environmental sample and cannot be compared to the WCB
OF BC limits but can be used to provide information concerning the amount of nitrous oxide in
the room at any point during the labour and delivery.
5.0 RESULTS
5.1 Formaldehyde
5.1.1 Silica Gel Tubes – Area Samples
Silica gel sampling tubes were collected throughout the sampling day. Three tubes were used for
short term sampling for less than 125 minutes and one tube was used for 317 minutes. The
results of all tubes were below the detection limit of 1.0 µg/sample. The blank was also
< 1.0µg/sample.
5.1.2 Colorimetric Tubes – Personal Samples
Gastec direct-reading colorimetric tubes were used to determine nurse exposure to formaldehyde
while it was being dispensed. A table with the results can be found in Appendix 4 of this report.
The results of breathing zone samples 1,2 and 5-8 were all below the detection limit of the tubes
which was 0.05 ppm. Sample 3 was taken 3 cm above a container of formalin to determine the
presence of formalin. Breakthrough (concentration exceeded tube capacity) was (>1 ppm)
observed with 3 of the 5 strokes of the Gastec pump. Sample 4 was taken above the formalin
stain located on the cardboard surrounding the formalin container. Breakthrough was also
observed with this sample before the 5 strokes of the pump could be completed.