MICROBIAL MONITORING DURING BIOAUGMENTATION WITH DEHALOCOCCOIDES - Bioaugmentation for Groundwater Remediation - page 176

to agitate at the midpoint of the well screen to avoid stirring up sediment in the sump
and/or at the bottom of the well.
4. While continuing to surge the well with the bailer, reconnect the flow-through cell and
record the field measurements for pH, ORP, specific conductance, temperature, dis-
solved oxygen and turbidity until stabilization of geochemical parameters is achieved.
5. Disconnect the flow-through cell but continue to surge the well with the bailer through
the sample collection process.
(a) In order to sample groundwater for off-site biomass collection, fill the appropri-
ate sample containers (e.g., clean, sterile 1-L amber glass or plastic bottles with
Teflon # -lined caps, no preservatives added) directly from the effluent end of the
pump. The bottles should be filled with groundwater from tubing that has already
been used to withdraw one to two well volumes of groundwater to ensure that
a representative sample of aquifer water, rather than well water, is collected. The
bottles should be filled to capacity (i.e., minimal headspace) to minimize air
exposure. Apply the Teflon # -lined caps and ensure a tight seal.
(b) For on-site biomass collection, use sterile Sterivex ™ -GP 0.22-micrometer ( m m)
membrane filter cartridges. Attach ¼- 5= 16 -inch polyethylene tubing to the inlet of
the Sterivex ™ cartridge and secure with a clamp. Place the cartridge over a
graduated cylinder that can accurately measure the volume of water filtered.
Ideally, 0.5-2 L of water should be collected; however, depending on groundwa-
ter characteristics, up to 10 L may be filtered, and as little as 10 mL may be
sufficient for subsequent biomarker analysis. Close the inlet and the outlet of the
Sterivex ™ cartridge with male and female Luer-Lock plugs, respectively.
If needed, replicate samples should be collected consecutively without flow
interruption. Record the volume of filtered groundwater on the chain-of-custody
form and on the Sterivex ™ cartridge barrel with a black permanent marker, and
transfer each capped Sterivex ™ cartridge to a separate, new 50 mL Falcon conical
plastic tube.
6. Immediately after sampling, transfer samples to coolers with ice packs and/or blue ice
(in Ziploc # bags) to ensure refrigeration at 4 C until arrival at the analytical labora-
tory. Falcon tubes (50 mL) or equivalent containers are used to protect Sterivex ™
cartridges during shipping and storage. Use additional packing material, as appropri-
ate, to prevent movement and breakage during shipping, and place each sample in
separate Ziploc # plastic bags. The coolers with samples should be shipped for next day
delivery to the analytical laboratory. It is important to notify analytical laboratories
when samples are shipped to avoid delays in handling and processing that could affect
biomarker integrity.
7. Immediately following sample collection, record the sampling well location, the well
name, notes on individual samples (e.g., the volume of water that passed through each
Sterivex ™ cartridge), date and time of sampling, and the type of analyses requested.
Standard chain-of-custody forms must accompany each sample shipment.
A variety of analytical techniques can be used to obtain qualitative and quantitative
microbiological data for environmental samples. The monitoring objectives for a particular
sample (or site) will largely dictate the choice of analytical approach. Descriptions of these
techniques are provided in the following section.