The monitoring wells are sampled using the protocol listed in the RCRA Ground-Water
Monitoring Technical Enforcement Guidance Document.33 The volume of the water in the
casing is determined by measuring the water depth from the surface and the depth to the bottom
of the well. This latter measurement also determines whether siltation has occurred that might
restrict water movement in the screen area. For those wells in the glacial till that do not recharge
rapidly, the well is emptied and the volume of water removed is compared to the calculated
volume. In most cases, these volumes are nearly identical. The well is then sampled by bailing
with a dedicated Teflon bailer. The field parameters for these samples (pH, specific
conductance, redox potential, and temperature) are measured statically. For those samples in the
porous, saturated zone that recharges rapidly, three well volumes are purged using dedicated
submersible pumps while the field parameters are measured continuously. These parameters
stabilize quickly in these wells. In the case of the dolomite wells, samples are collected as soon
as these readings stabilize. Samples for VOCs, SVOCs, PCB/pesticides, metals, and
radioactivity are collected in that order. The samples are placed in precleaned bottles, labeled,
and preserved.
During each sampling event, one well is selected for replicate sampling. An effort is made to vary this selection so that replicates are obtained at every well over the course of time. In addition, a field blank is also obtained.
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