Singer Furn_EQM Response to NOTI on RCRA Facility Inv Rpt-OCR

Comment to RS1sponse 13
Ground water contamination in the landfill area has not been adequately defined. Additional
monitoring wells are needed to define the lateral and vertical extent of ground water contamination.
Once contamination has been adequately defined, potential corrective action measures (if needed)
for the landfill can be addressed. If monitored natural attenuation is chosen as a corrective measure,
natural attenuation must be proven to be occurring and is sufficient to remediate the contamination.
Comment to Response 14
As discussed in the January 14, 1998 site meeting, the background sampling locations are
acceptable. Additional sampling is required to show that the contaminants, other than heavy metals,
detected at the background sampling locations are in fact laboratory/method artifacts.
Comment to Response j 5
Contamination in environmental media (soil, groundwater, surface water, air, etc .. ), based on the
definition in Singer's permit, is when a hazardous constituent is detected above either naturally
occurring background concentrations for naturally occurring constituents or above practical
quantitation limits for non-naturally occurring constituents. As stated in Singer's Response 15, "The
RFI was designed to establish the nature and extent of contamination ... " The extent of ground water
contamination has not been defined at the site. Benzene and trichloroethene (TCE) have been
detected, above North Carolina Administrative Code (NCAC) 2L ground water standards, at down-
gradient monitoring well CAMU1-4SP during all five sampling events for which it has been sampled
(except for TCE on October 26, 1995). Five out of five sampling events have detected TCE above 2L
standard at down-gradient monitoring well CAMU1-7SP (benzene has also been detected in three
out of five sampling events). Benzene and TCE were also detected at down-gradient monitoring well
CAMU1-8SP and benzene was detected at down-gradient monitoring well CAMU1-5SP and
background monitoring well BG-2SP. According to EQM well construction diagrams, the "SP" wells
were generally installed about five feet into the saprolite using a five foot screen with a sand pack
that extend a few feet up into the alluvial aquifer. The analytical and well construction data suggests
that the ground water in the saprolite may be relatively more contaminated than in the alluvium. In
c.:ddit!on, these 'Nelfs am th€ most dovm gradient \Netls at the faci!ity; indicating the lateral and vertical
extent of contamination has not been defined. Additional monitoring wells are needed to define the
lateral and vertical extent of ground water contamination.
Comment to Response 17
Contamination has been detected in all of the down gradient wells at the site that were installed in
the saprolite. At two locations, CAMU1-4SP (TCE and benzene) and CAMU1-7SP (TCE), volatile
organic compounds have been detected above NCAC 2L standards. One of the wells (CAMU1-4SP)
is located approximately 100 feet from Lower Creek. In addition, numerous other contaminants have
been detected in the ground water at many of the monitoring well locations, Including pesticides,
herbicides, or PCBs. Additional monitoring wells are needed to define the lateral and vertical extent
of contamination. If these wells indicates contamination has reached Lower Creek, then additional
investigation may be needed to determine the hydraulic interaction between ground water and the
creek.
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Co!-nment to Responses 18-21
Singer's determination that the site does not pose a risk to human health or the environment was
based on an industrial exposure scenario. A risk assessment based on an industrial exposure
scenario requires the use of some mechanism to restrict future land use to that of industrial. At this
time the NC Hazardous Waste Section has no mechanism available that can be used to enforce
future land use restrictions. Therefore, all risk assessments submitted to North Carolina's RCRA
program must be based on a residential exposure.
In regard to comment 18 of the NOT! and as stated in this letter, Singer must define the lateral and
vertical extent of contamination at the facility in both soil and ground water.
Comment to Response 22
Due to the lack of any local ordinances banning the installation of drinking water wells and the fact
that both the saprolite and the bedrock are capable of yielding enough water for domestic or
industrial use, Singer must consider future uses of ground water at and surrounding the Singer
facility. Singer must also consider the surface water pathway due to the close proximity of
contamination detected in the ground water to Lower Creek.
GENERAL COMMENTS
The specific comments listed above indicate that additional investigation of the Singer Facility is
needed in order to fully define the lateral and vertical extent of soil and ground water contamination.
The RFI report should be revised to reflect the need for the additional investigation.
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