such as chromium is an analyte of interest, the well casing or screen should not
increase or decrease the amount of chromium in the ground water. Any
material leaching from the casing or screen should not be an analyte of interest,
or interfere in the analysis of an analyte of interest.
In addition, monitoring well casing and screen materials should be relatively easy to install
into the borehole during construction of the monitoring well.
Owners and operators also should consider the purpose of the well when determining
the well's design. Will the well be used solely as a piezometer? Will the well be placed in
an area where there is currently no contamination and where natural water quality is not
likely to interact with it? Will the well be used to delineate the extent of a plume, but not
used to determine compliance with cleanup levels? Will the well be used to extract
contaminated ground water as part of corrective action activities? Will the well be used as a
point of compliance well for which accurate information is crucial?
The following discussion of casing and screen materials comes from several sources,
but the majority of it is directly from the EPA/EMSL Las Vegas Handbook of Suggested
Practices for the Design and Installation of Ground Water Monitoring Wells (Aller et al.,
1989), with additional information from various references, as cited. EPA believes that the
use of this up to date technical guidance, along with the technical criteria provided below, aid
in the selection of appropriate well materials. In addition to references cited by Aller et al.
(1989) the following references also are available for consideration when choosing well
casing and screen materials:
Cowgill, U.M. 1988. The Chemical Composition of Leachate from a Two
Week Dwell Time Study of PVC Well Casing and Three Week Dwell Time
Study of Fiberglass Reinforced Epoxy Well Casing, in A.G. Collins and A.I.
Johnson, eds., Ground Water Contamination: Field Methods, ASTM STP 963,
American Society for Testing and Materials, Philadelphia, PA, pp. 172 184.
Gillham, R.W. and S.F. O'Hannesin. 1990. Sorption of Aromatic
Hydrocarbons by Materials Used in Construction of Ground Water Sampling
Wells, in D.M. Nielsen and A.I. Johnson, eds., Ground Water and Vadose Zone
Monitoring, ASTM STP 1053, American Society for Testing and Materials,
Philadelphia, PA, pp. 108 122.
Hewitt, A.D. 1989. Leaching of Metal Pollutants from Four Well Casings
Used for Ground Water Monitoring. CRREL Special Report 89 32, U.S. Army
Cold Regions Research and Engineering Laboratory, Hanover, NH 03755 1290.