[Federal Register Volume 84, Number 140 (Monday, July 22, 2019)]
[Proposed Rules]
[Pages 35054-35059]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-15419]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 300
[EPA-HQ-SFUND-1990-0010; FRL-9996-76-Region 4]
National Oil and Hazardous Substances Pollution Contingency Plan;
National Priorities List: Partial Deletion of the Townsend Saw Chain
Co. Superfund Site
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule; notice of intent.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) Region 4 is issuing
a Notice of Intent to Delete the soil, sediment, surface water,
surficial aquifer, and the intermediate aquifer of this Site with the
exception of a limited area (5,000-8,000 square feet) of the
intermediate aquifer below the 1C clay in the vicinity of monitoring
wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain Co.
Superfund Site (Site) located in Pontiac, South Carolina, from the
National Priorities List (NPL) and requests public comments on this
proposed action. The NPL, promulgated pursuant to section 105 of the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) of 1980, as amended, is an appendix of the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). The EPA and the
State of South Carolina, through the South Carolina Department of
Health and Environmental Control (SC DHEC), have determined that all
appropriate response actions at these identified media and/or parcels
under CERCLA except for five-year reviews, operations and maintenance
and monitoring have been completed. However, this deletion does not
preclude future actions under Superfund. All Site areas and media will
be included in this partial deletion except for the groundwater in the
intermediate aquifer as specified above which will remain on the NPL
and are not being considered for deletion as part of this action.
DATES: Comments must be received by August 21, 2019.
[[Page 35055]]
ADDRESSES: Submit your comments, identified by Docket ID no. EPA-HQ-
SFUND-1990-0010, by one of the following methods:
http://www.regulations.gov. Follow the online instructions
for submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e. on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
Email: Joydeb Majumder, Remedial Project Manager,
[email protected].
Mail: Joydeb Majumder, Remedial Project Manager, Superfund
and Emergency Management Division, Superfund Restoration and
Sustainability Branch, U.S. Environmental Protection Agency, Region 4,
61 Forsyth Street SW, Atlanta, Georgia 30303-8960.
Hand delivery: USEPA Region 4 Superfund Record Center,
Attention: Tina Terrell, Records Center, Superfund and Emergency
Management Division, Superfund Enforcement Branch, U.S. Environmental
Protection Agency, Region 4, 61 Forsyth Street SW, Atlanta, Georgia
30303-8960. Monday to Friday 7:30 a.m. to 4:30 p.m.; Phone: 404-562-
9121.
Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
1990-0010. EPA policy is that all comments received will be included in
the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov website is
an ``anonymous access'' system, which means the EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an email comment directly to the EPA without
going through http://www.regulations.gov, your email address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If the EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, the
EPA may not be able to consider your comment. Electronic files should
avoid the use of special characters, any form of encryption, and be
free of any defects or viruses.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in the hard
copy. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at:
(1) USEPA Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-
8960, Monday-Friday 7:30 a.m.-4:30 p.m., Contact Tina Terrell 404-562-
8835; and
(2) Northeast Regional Library, 7490 Parklane Road, Columbia, South
Carolina, Monday--Thursday: 9:00 a.m.-9:00 p.m., and Friday-Saturday:
9:00 a.m.-6:00 p.m., Phone: (803) 736-6575.
FOR FURTHER INFORMATION CONTACT: Joydeb Majumder, Remedial Project
Manager, Superfund Restoration and Sustainability Branch, Superfund and
Emergency Management Division, U.S. Environmental Protection Agency,
Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-8960, phone 404-
562-9121, email: [email protected]
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Introduction
II. NPL Deletion Criteria
III. Deletion Procedures
IV. Basis for Intended Partial Site Deletion
I. Introduction
EPA Region 4 announces its intent to delete the soil, sediment,
surface water, surficial aquifer, and the intermediate aquifer with the
exception of a limited area (5000-8000 square feet) of the intermediate
aquifer below the 1C clay in the vicinity of monitoring wells IMW-01B,
MW-128, and OW-143 of the Townsend Saw Chain Co. Superfund Site (Site),
from the National Priorities List (NPL) and requests public comment on
this proposed action. The NPL constitutes Appendix B of 40 CFR part 300
which is the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP), which EPA promulgated pursuant to Section 105
of the Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA) of 1980, as amended. EPA maintains the NPL as the list of
Site that appear to present a significant risk to public health,
welfare, or the environment. Sites on the NPL may be the subject of
remedial actions financed by the Hazardous Substance Superfund (Fund).
This partial deletion of the Townsend Saw Chain Co. Superfund Site is
proposed in accordance with 40 CFR 300.425(e) and is consistent with
the Notice of Policy Change: Partial Deletion of Sites Listed on the
National Priorities List. 60 FR 55466 (Nov. 1, 1995). As described in
300.425(e)(3) of the NCP, a portion of a Site deleted from the NPL
remains eligible for Fund-financed remedial action if future conditions
warrant such actions.
EPA will accept comments on the proposal to partially delete this
Site for thirty (30) days after publication of this document in the
Federal Register.
Section II of this document explains the criteria for deleting
Sites from the NPL. Section III discusses procedures that the EPA is
using for this action. Section IV discusses the soil, sediment, surface
water, surficial aquifer, and the intermediate aquifer with the
exception of the intermediate aquifer below the 1C clay in the vicinity
of monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw
Chain Co. Superfund Site and demonstrates how it meets the deletion
criteria.
II. NPL Deletion Criteria
The NCP establishes the criteria that the EPA uses to delete Sites
from the NPL. In accordance with 40 CFR 300.425(e), Sites may be
deleted from the NPL where no further response is appropriate. In
making such a determination pursuant to 40 CFR 300.425(e), EPA will
consider, in consultation with the State, whether any of the following
criteria have been met:
i. Responsible parties or other persons have implemented all
appropriate response actions required;
[[Page 35056]]
ii. all appropriate Fund-financed response under CERCLA has been
implemented, and no further response action by responsible parties is
appropriate; or
iii. the remedial investigation has shown that the release poses no
significant threat to public health or the environment and, therefore,
the taking of remedial measures is not appropriate.
Pursuant to CERCLA section 121(c) and the NCP, EPA conducts five-
year reviews to ensure the continued protectiveness of remedial actions
where hazardous substances, pollutants, or contaminants remain at a
Site above levels that allow for unlimited use and unrestricted
exposure. The EPA conducts such five-year reviews even if a Site is
deleted from the NPL. The EPA may initiate further action to ensure
continued protectiveness at a deleted Site if new information becomes
available that indicates it is appropriate. Whenever there is a
significant release from a Site deleted from the NPL, the deleted Site
may be restored to the NPL without application of the hazard ranking
system.
III. Deletion Procedures
The following procedures apply to deletion of the soil, sediment,
surface water, surficial aquifer, and the intermediate aquifer with the
exception of the intermediate aquifer below the 1C clay in the vicinity
of monitoring wells IMW-01B, MW-128, and OW-143 of the Site:
(1) The EPA consulted with the State of South Carolina before
developing this Notice of Intent for Partial Deletion.
(2) The EPA has provided the state 30 working days for review of
this notice prior to publication of it today.
(3) In accordance with the criteria discussed above, the EPA has
determined that no further response is appropriate.
(4) The State of South Carolina, through the SC DHEC, has concurred
with the deletion of the soil, sediment, surface water, surficial
aquifer, and the intermediate aquifer with the exception of the
intermediate aquifer below the 1C clay in the vicinity of monitoring
wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain Co.
Superfund Site, from the NPL.
(5) Concurrently, with the publication of this Notice of Intent for
Partial Deletion in the Federal Register, a notice is being published
in a major local newspaper, the Greenville News. The newspaper
announces the 30-day public comment period concerning the Notice of
Intent for Partial Deletion of the Site from the NPL.
(6) The EPA placed copies of documents supporting the proposed
partial deletion in the deletion docket, made these items available for
public inspection, and copying at the Site information repositories
identified above.
If comments are received within the 30-day comment period on this
document, EPA will evaluate and respond accordingly to the comments
before making a final decision to partially delete the soil, sediment,
surface water, surficial aquifer, and the intermediate aquifer with the
exception of the intermediate aquifer below the 1C clay in the vicinity
of monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw
Chain Co. Superfund Site. If necessary, the EPA will prepare a
Responsiveness Summary to address any significant public comments
received. After the public comment period, if EPA determines it is
still appropriate to delete the soil, sediment, surface water,
surficial aquifer, and the intermediate aquifer with the exception of
the intermediate aquifer below the 1C clay in the vicinity of
monitoring wells IMW-01B, MW-128, and OW-143 of the Townsend Saw Chain
Co. Superfund Site, the Regional Administrator will publish a final
Notice of Partial Deletion in the Federal Register. Public notices,
public submissions and copies of the Responsiveness Summary, if
prepared, will be made available to interested parties and included in
the Site information repositories listed above.
Deletion of a portion of a Site from the NPL does not itself
create, alter, or revoke any individual's rights or obligations.
Deletion of a portion of a Site from the NPL does not in any way alter
the EPA's right to take enforcement actions, as appropriate. The NPL is
designed primarily for informational purposes and to assist EPA
management. Section 300.425(e)(3) of the NCP states that the deletion
of a Site from the NPL does not preclude eligibility for future
response actions, should future conditions warrant such actions.
IV. Basis for Intended Partial Site Deletion
The following information provides the EPA's rationale for deleting
the soil, sediment, surface water, surficial aquifer, and the
intermediate aquifer with the exception of the intermediate aquifer
below the 1C clay in the vicinity of monitoring wells IMW-01B, MW-128,
and OW-143 of the Site:
Site Background and History
Due to contaminated soils, sediments, groundwater, and surface
water, the EPA, EPA proposed listing the Site on the National
Priorities List (EPA ID: SCD980558050) on June 24, 1988 (53 FR 23988),
and finalized the listing on February 21, 1990, (55 FR 6154), under
CERCLA, 42 U.S.C. 9601. The 50-acre Site located in Pontiac, Richland
County, South Carolina was a small manufacturing facility located
approximately two miles south of Pontiac, South Carolina. Starting in
1971, Textron Inc., began utilizing the facility for manufacturing the
saw chain component of chain saws. Between 1964 and 1981, under the
Townsend Division of Textron, Inc. and a previous owner, Dictaphone
Inc., waste rinse waters from on-site plating and parts-assembly
processes were discharged to the ground surface in a low-lying area
adjacent to the facility. These discharges are the origin of the
groundwater and soil contamination. There is one sitewide operable unit
that includes soils, sediments, and groundwater associated with the
waste water rinse releases from the previous operation.
The Site consists of a 50-acre area associated with a former metal
products Manufacturing facility and is referred to as ``the Site'' in
this report. The leading edge of the contaminated groundwater plume has
also migrated to a 350-acre parcel of undeveloped land located to the
northeast across Spears Creek Church Road, which includes a 113-acre
Conservation Easement through the Congaree Land Trust. This 350-acre
parcel is referred to as the ``off-Site area.'' While the off-Site area
is technically part of the Superfund site, for ease of understanding,
the 50 acre parcel is referred to as ``off-Site'' to distinguish from
the 50-acre area. The Site has 2 underlying aquifers.
The portion of the Site being proposed for deletion in today's
action are soil, sediment, surface water, surficial aquifer, and the
intermediate aquifer with the exception of the intermediate aquifer
below the 1C clay in the vicinity of monitoring wells IMW-01B, MW-128,
and OW-143, for a limited area (5000-8000 square feet) in the vicinity
of the three wells. Since June 2016, all of the contaminated
groundwater plume has been remediated to levels below the Safe Drinking
Water Act Maximum Contaminant Levels (MCLs) except for a limited area
(5000-8000 square feet) in the vicinity of three wells located in the
on-site area (IMW-01B, MW-128, OW-143).
[[Page 35057]]
Site-specific geological and stratigraphic information was
developed during the installation of test borings and monitoring well
boring. Soils underlying the Site can be divided into three units; Unit
I exposed at the surface and consists of alternating layers of sand,
silty or clayey sand, and silt or clay lenses. These various layers
appear to be hydraulically connected. Perched water zones occur within
the upper part of Unit I. Unit II is a low-permeability confining unit
consisting of hard, dry, kaolinitic silty clays or clayey silt. Unit II
appears to be laterally continuous on the Site property. Unit III
consists of slightly silty, fine-to medium-grained sand. Because only a
few Site well borings have penetrated into Unit III, its hydrogeologic
and stratigraphic characteristics are not as well known. Units II and
III and the lower portion of Unit I are part of the Middendorf
Formation. Sand strata within the Middendorf are productive aquifers,
and the formation serves as a major aquifer in South Carolina.
There is potential redevelopment of the western portion of the Site
west of Spears Creek Church Road to commercial property including
retail and other commercial uses. AMBAC Intermodal (formerly American
Bosch), a manufacturer and supplier of fuel injection equipment
operates on approximately five acres of the fifty-acre Site. The
remaining portion of the Site east of Spears Creek Church Road has been
redeveloped to various commercial uses.
Remedial Investigation and Feasibility Study (RI/FS)
In August 1991, the EPA entered into an Administrative Order on
Consent with Homelite Division of Textron, Inc. to perform a Remedial
Investigation/Feasibility Study (RI/FS). Investigation results
indicated that hazardous substances, including chromium and volatile
organic compounds (VOC) were present in soil and groundwater at the
Site and groundwater and surface water in the off-Site area.
A Baseline Risk Assessment (BRA) was conducted in 1993. The BRA
concluded that, under the industrial land use scenario that existed at
the Site in 1993, the Site did not present any unacceptable human
health risks via any medium. However, under the anticipated future land
use scenario, which assumed residential and commercial land uses in the
off-Site area and continued industrial land uses on the Site, excess
human health risks existed through contact with contaminated ground
water (e.g. ingestion, inhalation, and dermal exposure).
The Feasibility Study, completed on August 19, 1996, considered
remedial options including a Resource Conservation and Recovery Act
(RCRA) cap, solidification/stabilization, in-situ chemical treatment,
and excavation/offsite disposal as alternatives to address contaminated
soils. The FS considered groundwater use restrictions/institutional
controls, groundwater extraction/treatment/spray field discharge,
groundwater extraction/treatment/publicly-owned treatment works (POTW)
discharge, and in-situ chemical treatment to address contaminated
groundwater.
Selected Remedy
On December 22, 1993, an Interim Record of Decision (IROD) was
issued for the Site. The interim remedy selected in the IROD was
intended to prevent the continued off-Site migration of the chromium-
contaminated groundwater plume. The interim action consisted of the
following remedial components:
(1) Planning and execution of a hydrogeologic investigation that
would support the remedial design of an Interim Action Pump and Treat
System (IAPTS). This system would, at a minimum, prevent further off-
Site migration and enlargement of the contaminant plume; and
(2) Expeditious design and construction of such a system and
initiation of ground water pump-and-treat operations.
The EPA issued the ROD for the Site on December 19, 1996. Based on
the results of the RI/FS and the Baseline Risk Assessment, the EPA
determined that remediation of soils, groundwater, and sediments would
be required for the protection of human health and the environment.
The remedial action objectives includes:
Soils
Prevent the leaching of contamination into groundwater, which can
contribute to human health risk via groundwater;
Groundwater
(1) Prevent exposure to chemicals of concern in groundwater which
pose an unacceptable human health risk;
(2) Reduce concentrations of chemicals of concern, thereby
restoring potential use of the aquifer as a potable water source; and
(3) Prevent or reduce the continued discharge of contaminated
groundwater to surface water, such that surface water quality standards
are not exceeded.
Surface Water
(1) Reduce contamination to levels which (a) cannot pose ecological
risk to tributary flora and fauna, and (b) are incapable of
recontaminating tributary sediment;
(2) Prevent exposure of the tributary ecosystem to chemicals of
concern, and/or reduce the concentrations of chemicals of concern such
that no unacceptable ecological risks are present. The selected remedy,
as stated in the ROD, included several major components and a
contingency remedy. The selected remedy includes:
Soil Treatment
(1) Excavation and removal of the uppermost highly contaminated
soils, and treatment of surficial soils through in-situ chemical
treatment.
Groundwater Remediation
(1) In-situ chemical treatment of ground water;
(2) Continued operation of IAPTS; and
(3) Sediment removal action at the off-Site area seep (to be
performed upon completion of the chromium ground water cleanup.
Site Monitoring
(1) Continued quarterly sampling/analysis of Site ground water.
(2) Additional quarterly sampling of surface water in the unnamed
off-Site tributary. and
(3) Periodic sampling of treated Site soils.
Response Actions
The Remedial Design and Remedial Action were implemented by
Textron, Inc. through two Unilateral Administrative Orders. The Site's
principal exposure pathway of concern was ingestion of groundwater.
Therefore, the soil cleanup goal was based upon leachability to
groundwater. Although not prescribed in the Site's Interim Record of
Decision, approximately 75 tons of soils from hotspot areas
contaminated with chromium, lead, and several other heavy metals, were
excavated and disposed of properly in 1995 and 1996. The excavations
were located near the northeast and northwest corners of the
manufacturing facility. Soils with contamination above the cleanup goal
for hexavalent chromium had been removed and no further soil
remediation was required based on currently available data. Between
June and December 1995, a five-well IAPTS was constructed and new
treatment equipment installed for the wastewater treatment system. The
system consisted
[[Page 35058]]
of the three original recovery wells located along Spears Creek Church
Road, and two new recovery wells located in the off-Site area. The
IAPTS began operating in December 1995. Groundwater from these wells
was pumped to a treatment facility at the manufacturing facility and
treated in electrochemical precipitation cells. Treated groundwater was
then discharged to an on-Site, South Carolina DHEC-permitted spray
field.
Remedial design work for the in-situ chemical treatment technology
began in May 1997 and was completed in September 1999. Injection lines
of wells on 40-foot centers were used to place a ferrous sulfate
solution in contact with chromium contaminated groundwater. The
solution converted the main contaminant, hexavalent chromium, into an
inert and harmless type of chromium mineral, which remains safely in
the subsurface. The 2001 ESD established an updated chromium soil
cleanup number. Based upon this ESD, no additional soil cleanup was
necessary.
In April 2002, the IAPTS was shut down as a trial measure because
it was thought to be affecting groundwater flow pathways and
potentially affecting chemical treatment activities. The system has
remained shut down since this time. While in operation, the IAPTS
recovered over 550 pounds of chromium from groundwater. During 2000-
2003, the in-situ treatment was implemented along successive injection
well lines, proceeding northeastward across Spears Creek Church Road
and into the off-Site area. Since 2002, the off-Site area was largely
the focus of treatment; however, spot treatments have been performed on
small resistant areas within the former plume area onsite. In September
to October 2004, seven additional monitoring wells were installed in
four locations in the off-Site area. The wells were installed to better
characterize groundwater flow direction both above and below the 1C
clay.
The Explanation of Significant Difference (ESD) issued in April
2007, was to add two remedy components to the original remedy to
enhance remedy performance and to place the IAPTS into stand-by mode.
The two new remedy components were institutional controls (ICs) over
the 39.79 acres portion of the Site on the western side of Spears Creek
Church Road including parcel 28800-01-03 and a portion of parcel 28800-
01-22 and installation of a Permeable Reactive Barrier (PRB) in the
off-Site area to prevent discharge of TCE and chromium contaminated
groundwater to surface water. The objectives for ICs were to (1)
restrict the use of ground water as a drinking water source until MCLs
are met for the Site and off-Site area; (2) restrict the use of the
Site (property associated with original facility operations) to
commercial, industrial, or light industrial land uses only; and (3)
restrict the use of the off-Site area in order to protect the future
PRB from damage. The IAPTS would remain in stand-by mode until
determined that it needed to be reactivated or dismantled.
To enhance groundwater cleanup, a bio-stimulation approach and a
pilot test of a combination of fatty acids and ferrous sulfate
injection system (creating a BioBarrier) was conducted in 2009. Based
on the results of the pilot study, construction of the BioBarrier by
injection was initiated in 2010 in lieu of the PRB proposed in the 2007
ESD. The initial BioBarrier consisted of twelve new wells for injection
of the carbon source substrate that were installed along the top of the
slope (upgradient area) and three new injection wells in the
downgradient area in late 2011.
As of 2012, the BioBarrier had reduced chromium concentrations in
the leading edge of the plume to below MCLs. A second round of Phase 2
ferrous sulfate injections were conducted in 2012 and completed by
April 2013. By mid-2013, the combination of the BioBarrier and
upgradient ferrous sulfate injections, the overall plume area had been
reduced to 53,400 square feet from an original size of 400,250 square
feet. Since that time, remedial activities at the Site have largely
consisted of installation of injection wells and injection of the
carbon source amendment to address residual areas of the plume. Since
June 2016, all of the plume has been remediated to levels below the MCL
except for a limited area (5000-8000 square feet) in the vicinity of
three wells located in the ``on-Site area'' (IMW-01B, MW-128, OW-143).
In 2013, fourteen new injection wells were installed. Seven
injection wells were installed in the perched groundwater table in the
western area of the Site and seven injection wells were installed in
the BioBarrier area to augment existing injection wells.
Cleanup Levels
The Remedial Design for the Soil/Sediment remedy began in 1995 and
was completed in 1997 by the PRP with EPA oversight. Soil cleanup
levels for chromium were attained by soil removals conducted in 1996.
As of April 2017, all groundwater monitoring wells with the exception
of IMW-01B, MW-128, and OW-143 in the intermediate aquifer below the 1C
clay had attained and maintained the groundwater cleanup goals for a
period of at least eight separate and distinct sampling rounds pursuant
to the February 24, 2015, Textron Verification Monitoring Strategy.
Semi-annual sampling of surface water and sediments in the
tributary to Spears Creek have demonstrated a declining trend in
(contaminant or chromium) concentrations over the past eight years as
groundwater remediation progressed. The ESD did not establish a
chromium cleanup goal for sediment. The 2010 Five-Year review
referenced the Ecotox threshold of 81 mg/kg for total chromium.
Chromium concentrations are below screening values in 11 of 12 samples
analyzed at 4 locations and any sporadic exceedances do not present
significant risks to ecological receptors. No additional response
action for chromium in sediments was required.
The Ambient Water Quality Criteria (AWQC) for surface water for
ecological protection for hexavalent chromium is 11 ug/L and the AWQC
for trivalent chromium is 74 ug/L which are typically adjusted for
hardness. The 2001 ESD set the stream cleanup goal as 40 ug/L which was
retained in the 2010 and 2015 five-year reviews. As of July 2016,
surface water sampling results for total and hexavalent chromium had
been well below that level for eight sampling events and below
detection levels for six sampling events.
Operation and Maintenance
EPA approved an Operations, Maintenance, and Performance Monitoring
Plan for the Site in August 2001. This plan encompasses the operation
and maintenance of both the in-situ chemical injection treatment and
pump-and-treat systems. The Plan was revised in March 2002, to shut
down the IAPTS as a trial measure. The Site's 2007 ESD further
stipulated that the IAPTS should be maintained in a stand-by condition
for reactivation, if needed. The 2010 five-year review listed as one
recommendation the evaluation of the need to continue holding the lAPTS
in stand-by condition at the Site due to the improved performance of
the in-situ treatment. The November 22, 2010, semiannual groundwater
results demonstrated two years of consecutive reduction in the
contaminant plume size and contaminant concentrations.
In 2012, an assessment of historic and recent volatile organic
chemical concentration data at the Site was conducted for the three
chlorinated VOCs that had been detected over time (perchloroethylene,
trichloroethylene, and 1,1 dichloroethylene). The data
[[Page 35059]]
evaluation determined that the initially low concentrations observed at
the Site had declined over time due to attenuation and the in-situ
reductive processes employed in the remediation. Groundwater MCLs for
the 3 VOCs are met. The potential for vapor intrusion issues was also
evaluated using the most conservative (95th percentile) and median
attenuation factors for soil types. Allowable groundwater
concentrations were back-calculated from USEPA indoor air Regional
Screening Levels, the indicated attenuation factors, and Henry's Law
Constants. All detections of perchloroethylene and 1,1 DCE in the most
recent data were below the allowable groundwater concentrations
calculated using the most conservative attenuation factors. The most
recent TCE groundwater concentrations were an order of magnitude below
with the allowable concentrations derived from the median attenuation
factors for depths of greater than 5 meters which corresponds with Site
groundwater depths (approximately 30 ft bgs). Additionally, all VOC
detections were from wells screened below the middle clay layer which
provides a barrier to vertical vapor migration or adjacent to the
Congaree Land Trust where development would be prohibited. There is no
vapor intrusion pathway of concern at the Site.
The monitoring wells located on and around the Site are regularly
sampled at designated quarterly or semi-annual intervals. Groundwater
sampling at monitoring wells will continue until all the remedial goals
for all contaminants are achieved at the three remaining monitoring
wells that have not yet attained Site cleanup standards. Future
groundwater restoration activities may include additional subsurface
injections of ferrous sulfate and a blend of fatty acids to address
chromium MCL exceedances in the intermediate aquifer below the 1C clay
in the vicinity of monitoring wells IMW-01B, MW-128, and OW-143.
Institutional Controls (ICs)
The 2007 ESD required ICs over the 39.79 acres portion of the Site
on the western side of Spears Creek Church Road including parcel 28800-
01-03 and a portion of parcel 28800-01-22. The restrictions limit soil
and groundwater use and restrict the property use to commercial,
industrial or light industrial uses. Groundwater use is prohibited for
potable, irrigation or other uses except with express written consent
of Textron, Inc. This was implemented in a Declaration of Covenants and
Restrictions recorded on Deeds recorded at the Richland County Register
of Deeds on February 9, 2007 in Instrument #2007011804. The ICs are
recorded on the deed, are transmitted to successors, and are verified
during the five-year Review process.
Five-Year Review
Previous five-year reviews were conducted because hazardous
substances remained on Site above levels which allowed for Unlimited
Use/Unrestricted Exposure and the Site groundwater had not attained all
cleanup levels contemplated in the Record of Decision (ROD) and
subsequent Explanation of Significant Difference (ESD). Five year
Reviews will no longer be conducted at the portions of the Site deleted
from the NPL which achieved Unrestricted Use/Unlimited Exposure (UU/
UV). Five-year reviews will continue to be conducted for that portion
of the Site designated for industrial and commercial uses. A 39.79-acre
portion of the Site including parcel 28800-01-03 and a portion of
parcel 28800-01-22 meets clean up criteria, but has Institutional
Controls, requires five-year reviews and does not meet Unlimited Use/
Unrestricted Exposure criteria. Five-year reviews will continue for
that portion of the groundwater of the Site still on the NPL. The last
five-year Review was completed in July 2015 and found the remedy
protective of human health and the environment. There were no Issues or
Recommendations in the Five-Year Review. The next Five-Year Review is
scheduled to be completed in July 2020.
Community Involvement
On June 12, 1991, April 14, 1992, August 23, 2001, and June 6,
2006, EPA, SC DHEC, and Textron representatives conducted public
availability sessions for RI/FS kickoff, the interim groundwater remedy
ROD, and two Explanation of Significant Difference proposals addressing
groundwater. On August 31, 1993 and September 17, 1996, EPA, DHEC, and
Textron representatives conducted proposed plan meetings. EPA conducted
community interviews during December 10-13, 1991, prior to the Site
National Priority Listing. EPA and DHEC conducted community interviews
for the three Five-Year reviews in 2005, 2010, and 2015.
Determination That the Criteria for Deletion Have Been Met
The EPA has followed procedures required by 40 CFR 300.425(e)
regarding requirements for deletions. EPA consulted with the State of
South Carolina through the SC DHEC. South Carolina issued a May 12,
2017, concurrence letter indicating its agreement with today's proposed
action.
The implemented remedy achieves the degree of cleanup or protection
specified in the ROD and ESD for the areas proposed for deletion. The
selected remedial and removal action objectives and associated cleanup
levels for the areas proposed for deletion are consistent with agency
policy and guidance. No further Superfund response in the areas
proposed for deletion are needed to protect human health and the
environment.
List of Subjects in 40 CFR Part 300
Environmental protection, Air pollution control, Chemicals,
Hazardous waste, Hazardous substances, Intergovernmental relations,
Penalties, Reporting and recordkeeping requirements, Superfund, Water
pollution control, Water supply.
Authority: 33 U.S.C. 1321(d); 42 U.S.C. 9601-9657; E.O. 13626,
77 FR 56749, 3 CFR, 2013 Comp., p. 306; E.O. 12777, 56 FR 54757, 3
CFR, 1991 Comp., p. 351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp.,
p. 193.
Dated: June 19, 2019.
Mary S. Walker,
Regional Administrator, Region 4.
[FR Doc. 2019-15419 Filed 7-19-19; 8:45 am]
BILLING CODE 6560-50-P