ing eight times (~7C to 2C), from freezing to thaw-
the "winter." The meltwater fractions were drawn off
ing temperatures 12 times (~1C to 5C), from thaw-
into sterile glass dilution bottles. Each bottle was com-
pletely filled. In some instances, partially filled bottles
ing temperatures to even warmer temperatures four
times (~3C to 10C), and then remained warm on the
were stored briefly in the refrigerator until enough
last day (9C to 14C). The complete cycling schedule
leachate could be collected to fill the bottle.
is given in Table A1.
Snow column construction
We were unable to collect meltwater samples until
Columns were made of 14.9-cm-internal-diameter
the column was kept at temperatures consistently above
0C. Meltwater fractions were collected in 160-mL ster-
(i.d.) PVC pipe and were 101.6 cm tall. A 15.9-cm-i.d.
end cap was fitted on the bottom end. The end cap was
ile glass dilution bottles, but only selected samples were
not solvent-bonded but the upper (outside) rim of the
analyzed, depending upon the number of available
end cap was sealed with medium-set PVC cement. So
samples that could be processed that day. After the last
that sample could be drawn from the bottom of the col-
meltwater fraction was taken, one bottle of sterile buff-
umn, a small (~2.5-cm) hole was drilled through the
ered dilution water was poured into the PVC column,
lower end of the PVC pipe and end cap. A plastic barbed
the water in the column was then swirled, and the rinse-
fitting was placed in the hole and tightened until it did
water sample was then collected from the bottom of
not leak. Tygon tubing (0.95-cm i.d.) was attached to
the column.
the fitting and secured to the fitting with a small pipe
Second indoor study
clamp. A C-type tubing clamp was placed on the other
end of the tubing and was left in the closed position
Prior to starting this experiment, the snow used in
this study was moved from storage at 10C
except when samples were drawn off. Samples were
(14F) to 15C (5F), where it was stored for
collected only when there was flow from the tubing;
no suction was applied. The sides of the columns were
several weeks. The temperature of the incubator was
wrapped with a layer of 2.2-cm Armaflex foam insula-
cycled from temperatures that were well below freez-
ing to slightly below freezing nine times (~7C
tion to promote warming from the top and bottom of
to 1C), from freezing to thawing temperatures once
the snow column, rather than the sides, and thus simu-
but held for four days (~0C to 5C), and from tem-
late what would happen in the snowpack. Prior to start-
ing an experiment, the inside of the column and tubing
peratures slightly above thawing to warmer tempera-
tures 12 times (~3C to 9C). The complete cycling
were washed with a detergent solution, rinsed with co-
pious amounts of tap water, and then rinsed three times
schedule is given in Table A2. The meltwater fractions
with distilled water.
were collected in 480-mL, sterile glass bottles. By col-
As snow was packed in the PVC columns, snow
lecting the samples in larger bottles, we were able to
samples were taken to determine the initial level of con-
analyze all the meltwater fractions. The column was
tamination in the snow at the start of the experiment.
rinsed as described previously and the rinse water was
collected.
Test procedures for snowmaking study
Outdoor study
Wastewater was collected after leaving the lagoon
The snow used in this study was stored at 10C.
and prior to entering the snow guns in 110-mL sterile,
polypropylene containers with snap lids. The freshly
The snow column was placed outside in an open
fallen manufactured snow was collected and placed in
field on the morning of a sampling day. Meltwater
the same type of containers. All the containers were
fractions were drawn off until late afternoon. The
placed in insulated coolers containing bags of snow and
column was then either left outdoors and sampled the
transported back to our laboratory for analyses later that
next morning at approximately 7:00 a.m. or was
placed in the environmental chamber at ~0C for
afternoon and evening. The snow samples were melted
at room temperature prior to analyses. Samples were
storage until the next sampling day. The schedule is
collected from approximately 7:45 a.m. to 9:45 a.m.
given in more detail in Table A3. The meltwater
The high temperature for that day was 10.6C (13F)
fractions were collected as described in the previous
and the low was 19.4C (3F).
study, and all fractions were analyzed. The column was
rinsed as described previously and the rinse water was
Test procedures for snow column studies
collected.
First indoor study
Microbiological analyses
In this study, the temperature of the incubator was
Microbiological tests included enumerating the to-
tal number of heterotrophic bacteria at 37C (the growth
cycled from well below freezing to slightly below freez-
5
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