NCD981021157_19920925_New Hanover County Airport Burn Pit_FRBCERCLA ROD_Final Record of Decision Amendment - Groundwater Remediation-OCR

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
SEP 2 5 1992
4WD-NCRS
Mr. Michael A. Kelly
Deputy Director
North Carolina Department of Environment,
Health, and Natural Resources
Division of Solid Waste Management
P.O. Box 27687
Raleigh, North Carolina 27611-7687
I RE: State~s Concurrence on the New Hanover County Airport
Burn Pit Superfund Site Record of Decision
Dear Mr. Kelly:
EPA-Region IV appreciates the State's concurrence on the Record of Decision (ROD)
for the New Hanover County Airport Burn Pit Superfund Site located in Wilmington,
North Carolina. For the record, EPA would like to respond to•your September 24,
1992· concurrence letter. Your letter, along with this response, will be included
in Appendix A of the ROD. These letters should stand as official documentation
that EPA-Region IV and North Carolina Department of Environment, Health, and
Natural Resources have agreed on the preferred alternatives at this point in
time.
For your information, the Agency has incorporated the States' s groundwater
standard of 1. 0 ug/1 for benzene as the performance standard in the ROD. And the
Agency recognizes that the State may in the future put in place, pursuant to
State law (General Statute 130A-310, 8), a deed recordation/restriction to
document the presence of residual contamination which may limit the future use
of the property.
Please contact me at (404)3457-7791 if you have any questions or comments
regarding this matter.
sincerely yours,
Jon K. Bornholm
Remedial Project Manager
cc: Curt Fehn, EPA
'John "Walch, NCDEHNR ,,
···1
Printed on Recycled Paper
• NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Mr. Charlie Steahman
Groundwater Supervisor
.Wilmington Regional Office
127 Cardinal Drive Extension
Wilmington, NC 28405
December 6, 2000
RE: Final Record of Decision Amendment
Groundwater Remediation
New Hanover County Airport Burn Pit
NCO 981 021 157
Wilmington, New Hanover County, NC
Dear Charlie:
DIVISION OF WASTE MANAGEMENT
The NC Superfund Section has reviewed the Amendment to the Record of
Decision (ROD) dated March 30, 2000 for the New Hanover County Airport Burn Pit
Superfund Site, Groundwater Remediation, located in Wilmington, NC and concurs
with the selected remedy, subject to the following conditions.
I. Since remediation of the soil at the subject Site was completed in I 989 and the
groundwater is expected to meet State and federal cleanup levels within three to
five years, the State does not foresee long-term groundwater contamination that
would prevent unrestricted use of the property. Therefore, the State does not
require deed recordation or restrictions in accordance with NCGS l 30A-3 l 0.8,
Recordation of inactive hazardous substances or waste disposal sites.
2. State concurrence with this Amended Record of Decision (ROD) and the newly
selected remedy for the Site is based solely on the information contained in the
Amended ROD received by fax on May 15, 2000. Should the State receive new
or additional information which significantly affects the conclusions or remedy
selection contained in the Amended ROD, it may modify or withdraw this
concurrence with written notice to EPA Region IV.
3. State concurrence on this Amended Record of Decision (ROD) in no way binds
the State to concur in future decisions or commits the State to participate,
financially or otherwise, in the clean up of the site. The State reserves the right to
40 I OBERLIN ROAD, SUITE 1 SO, RALEIGH, NC 27605
PHONE [phone] FAX [phone]
AN EQUAL OPPORTUNITY I AFFIRMATIVE ACTION EMPLOYER -50% RECYCLE0/10% POST-CONSUMER PAPER
f?oj)
Mr. Charlie Steahman
12-6-2000
Page 2 of2
•
review, overview, comment, and make independent assessment of all future work relating to
this site.
Attached is a copy of the Record of Decision Amendment signed by the EPA Regional
Administrator on April 11, 2000. This copy of the ROD Amendment is for your review and
files. If you have any questions or comments please give me a call at, [phone], extension
341.
Sincerely, ~(\
QJ 1R -~ct~{\
Randy McElveen
Environmental Engineer
NC Superfund Section
cc: Grover Nicholson, NC Superfund Section
NORTH SUPERFUND ID : MRY 15'00 •
AMENDED RECORD OF DECISION
THE DECLARATION
Site Name and Location
New Hanover County Airport Burn Pit
Wilmington, Brunswick County, North Carolina
Statement of Basis and Purpose
10:58 No .005 P.05
This decision describes a fundamental change to the groundwater restoration approach
presented in the Record of Decision (ROD) of the New Hanover County Aiq,on Burn Pit Site
(the Site). As the result of information developed since the original ROD was finalized, the
United States Environmental Protection Agency (USEPA) has decided to choose airsparging as the new Selected Remedy for groundwater. This change to the original Selected Remedy was
chosen in accordance with Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA), as amended, and to the extent practicable, the National Oil and Hazardou.1
Substances Pollution Contingency Plan,
EPA· has determined that all soit remediation has been completed at the Site. Site-specific
data obt_a)ned pdo_r to the_ R9D indicated the aquifer or groupdl\'_ater plume flowing beneath and down gradient of the Site pose a threat to human health or the environment, Although
contaminant levels and risk to human health now appear to be minimal for this site, during a recent study of site conditions it could not be conclusively determined that natural attenuation of
contaminants in groundwater is occurring. Therefore, active groundwater remediation options have been reevaluated for this Site to achieve groundwater clean-up goals. Based on a site-
specific feasibility study and documents published by the USEPA for sites similar to the Burn Pit Site, air sparging appears to be a remedial treatment alternative which is technically and
economically supedor to the previously selected pump-and-treat alternative.
The State ofNonh Carolina concurs with this amendmeut to the ROD (See concurrcuce
letter Appendix A).
Rational For Selection of Air Sparglng As Groundwater Restoration Remedy
Air Sparglng
Air sparging remediation technology has been implemented with success at sites
contaminated with Volatile Organic Compounds (VOCs) and has gained general indust1y
acceptance in the last few years. It is one of the groundwater remedial technologies that the
USEPA has proposed for consideration at Supcrfund Sites because of its potential for providing a faster, more effective and less costly altem¥ivc to traditional cleanup methods, such as purnp-and-treat, ·
. NORTH SUPERFUND ID: MAY 15'00 10:59 No .005 P.06 •
Even though a pump-and-treat remedy was selected in the September 29, 1992 ROD as
the preferred remedy, air sparging technologies offer a number of other advantages over the
pwnp-and-treat approach. These advantages have been documented by the USEPA and include:
• The potential to substaatiaUy decrease the time required to achieve remedial goals,
Readily available equipment and easy installation,
• Requires no extraction, treatment, storage or discharge considerations for groundwater.
Fu1thcr, metal contaminants arc being deleted from the original ROD as Contaminants of
Concern (COC). Several sampling investigations using low flow (low turbidity) sampling were
completed by the Potential Responsible Parties (PRPs) and the results indicated that metal
contaminants were not present above Federal and State standards. Therefore, metals did not
require remediation and the air sparging technology was then considered as an available
remediation technology.
Statutory Determination
Considering the new info!Tlllltion that has been developed and the changes that have been
made to the Selected Remedy, USEPA believes that the remedy remains protective of human
health and the environm(:llt and complies with Federal and Sta\c requirernentnhat were identified
in the September 29, 1992 ROD, as applicable or relevant and appropriate to this remedial action
at the time the original ROD was signed The air sparging reri'.iedy ~atisfics the stat~tory . .
preference for treatment as a principle clement because it restores the shallow aquifer beneath the
Site.
Upon completion of this remedy, no hazardous or toxic substances are expected to remain
on-site above health based levels that prevent unlimited use and umcstricted exposure. However,
it is expected that it may take five years to achieve the clean-up goals. Therefore, a Five Y car
Review will be conducted within five years of completion of the Preliminary Close-Out Report.
Richard D. Green, Director
Waste Management Division
NORTH SUPERFUND ID: MRY 15'00 i0:59 No.005 P.07 •
Decision Summary
1.0 SITE NAME, LOCATION, AND DESCRIPTION
l. l Site Location
The New Hanover County Burn Pit Supcrfund Site is located on Gardner Drive, 500 feet
west of the New Hanover County Airport in New Hanover County, approximately 1.5 miles north
of Wilmington, North Carolina as shown in Figure I.
The approximately 1,500 square foot bum pit was located near the center of a four-acre
plot (see Figure 2) on the New Hanover County Airpo11 property.
1.2 Affected Population
The clo,sest residential.~rea to the Site is approximately 0.22 mi.Jes to the west of the Site.
This area is separated from the Site by a road, railroad tracks, and a wooded area. The plume of
· volatile organic compounds (VOCs) does not affect off-site residential or industrial pop·ulatibos" ..
since the known plume docs not extend more than 350 feet from the location of the original burn
pit.
1.3 Land Use
Land use in the vicinity is commercial, light industrial, and residential. There are rental car
maintenance facilities, a closed sawmi!Vlumberyard, and a trucking company to the cast and
northeast of the Site. The closest residential areas to the Site are approximately 0.22 miles to the
west of the Site. This area is separated from the Site by a road, railroad tracks, and a wooded
area.
The land immediately northeast, north, west, and south of the Site is forested with mixed
southern hardwoods typical of the coastal plain area. This wooded area extends for
approximately 300 to 500 feet west and north and 800 feet south of the Site.
l .4 Natural Resources
The groundwater under the Site is designated as Class GA in accordance with North
Carolina's groundwater classification system and Class IIB under USEPA Groundwater
Classification Guidelines (December 1986). The Class GA classification means that the
groundwater is an existing or potential solfrce of drinking water supply for humans as defined in
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HORTH SUPERFUHD ID: MAY 15'00 il:00 r✓o.005 P.08
I
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Title 15A, North Carolina Administrative Code, Subchapter 2L (Tl5A NCAC 2L). EPA
classifies the upper zone of the aquifer (i.e., the groundwater above of the blue clay layer) as Class
IIB since the aquifer is of drinking quality but is not currently being used as a source of drinking·
water. The groundwater beneath the blue clay layer is assumed to be interconnected with ·the
Castle Hayne Limestone formation and is therefore, classified as IIA. Class IIA is defined as an
aquifer that is currently being used as a drinking water source. For these reasons, the
groundwater needs to be remcdiated to a level protective of public health and the environment as
specified in federal and state rcgulatioos governing the quality and use of drinking water. Both
the Pee Dee and the Castle Hayne arc major drinking water sources for New Hanover County.
1,5 Site Operational History
The New Hanover County Airport Burn Pit was constructed by the County of New
Hanover in 1968. From 1968 to 1979, the Cape Fear Technical Institute (now known as the Cape
Fear Community College), used the bum pit for fire-training purposes, burning jct fuel and
gasoline in the burn pit, and extinguishing the fires with water. The Wilmington Fire Department
used the bum pit for fire-training purposes from 1968 to 1976 and the United States Air Force
used the burn pit for fire-training purposes during the Vietnam War.
Jct fuel and drainage from petroleum fuel storage ranks in the area were burned;-and the
fires were extingµisl_1cd with water., carbqu dioxide, and d_ry chpnicals. S1nn.c til1)c prior to 1982,
materials used in river spill cleanups were dumped into the burn pit.
In 1986, the North Carolina Division of Health Services discovered heavy metals and
nwnerous organics in the soil around the burn pit and in other nearby soil samples. Surface water
within three (3) miles downstream oftbc Site is used for recreational activities, and an estua1y
wetland is located approximately one ( 1) mile from the Site. Approximately 6,300 people obtain
drinking water from public and private wells within three (3) miles of the Site. A private well is
located approximately 1,500 feet to the northwest of the Site.
To date, EPA has identified four (4) potentially responsible parties (PRPs) at the Site: the
County of New Hanover, North Carolina; the City of Wilmington, Nonh Carolina; the Cape Fear
Community College; and the United States Air Force.
The Site was listed on the National Priorities List on March 31, 1989. EPA negotiated
with the three (3) municipal PRPs in March 1989, for performance of the remedial
investigation/feasibility study (Rl/FS ), but the parties were unable to reach an agreement, In May
1990, however, the parties signed an Administrative Order on Consent for a removal action.
During the removal, the PRPs removed all of the source material present at the Site at a cost of
$452,500.00.
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NORTH SUPERFUND ID: MAY 15'00 11 : 00 No . 005 P. 09 •
EPA conducted a fund-lead Rl/FS in 1991 and 1992, and issued a Record of Decision
(ROD) for the Site on September 29, 1992. The ROD contemplated pwnp-and-treat of the
groundwater to address low levels of benzene, ethyl benzene, lead, and chromium at an estimated
present worth cost of$1.5 million.
As part of the selected remedy, the ROD included a technical impracticability provision
and provided for an additional year of groundwater sampling for EPA to determine whether or
llOt natural attenuation was occurring in the groundwater. After six (6) rounds of sampling
conducted by EPA's Ecological Science Division, there was no evidence that natural attenuation
w11s occurring with any of the contaminants currently present in the groundwater.
1.6 Highlights of Community Participation
In accordance with CERCLA, Section 117 and the National Contingency Plan (NCP)
300.435(c)(2)(ii) a revised proposed plan was mailed to interested parties and other persons who
have requested to be included on USEPA's mailing list for the Site. The proposed plan
suppoI1ing infonnation was made available to the public in the information repository maintained
at the EPA Docket Room in Atlanta and at the New Hanover Public Library located at 210
Chestnut Street, Wilmington, North Carolina. Notice of availability of these documents were
· puolished in Wilmington Morning Star on,Novcmbcr I, 1999:
. .. The USEPA conducted a public meeting on November 36iT999. A comment period of
sixty days was provided to receive written or oral comments from the public from November 16,
1999 to January 15, 2000. At the public meeting, many residents were concerned about their
drinking water and surface water run-off. The citizens requested the USEPA to sample their
wells and to detemline if run-off from the Site and the contamination in the grouudwatcr from the
Site bad impacted their well water. Based on these concerns, the USEPA's Environmental
Services Division sampled the wells in the vicinity of tbe Site during the week of January 17,
2000. Results of this sampling event are expected in April 2000,
In response to comments at the public meeting, the NCDENR Superfund Section, county
officials and their consultants, and NCDENR Surface Water Quality personnel, completed
reconnaissance oftbe on-site and adjacent surface water pathways on January 13, 2000. On
January 21, 2000, NCDENR Surface Water Quality, Wilmington Regional Office, completed
surface water sampling in the areas agreed to by the North Carolina Supcrfund Section and the
Potentially Responsible Pa11ics (PRPs) during the reconnaissance on January 13, 2000.
NCDENR Surface Water Quality collected another set of surface water samples on
February 3, 2000. A NCDEl\'R Superfund Section representative and three residents from the
area were present during all or part of the surface water sampling event and observed sampling
locations and procedures. One of the four surface water samples collected on February 3, 2000
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NORTH SUPERFUND ID: MAY 15'00 11:01 No.005 P.10 • •
was at a different location than the 13 January sampling event. This change was made due to
recommendations from the local residents. The prelimina1y results from both sampling events
indicate no detection of any COCs or VOCs.
Only one w1itten comment was received during the 60 day public comment period. A
letter was submitted by residents requesting another thi.i1y days extension pending test results on
the sampling investigation. Since the preliminary results from the surface water samples indicated
no detection of any COCs or VOCs, and since any additional private well sampling results would
not impact treatment decisions at the burn pit, the USEPA felt that it was necessary to continue
the remedial schedule as planned to implement the proposed remedy.
2.0 REASONS FOR ISSUING THE ROD AMENDMENT
2.1 Description of the Original Selected Remedy
The groundwater remediation alternative originally selected for the New Hanover Site is
Alternative GWl/3 -Groundwater Extraction and Physical Treatment (Air Stripping) with
Discharge to Publicly Owned Treatment Waterworks (POTW). A dcsctiption of the original
selected remedial alternative follows.
"The selected ROP rcr;ncdy, wa~ pump and treat and was chosen because i\ was the most
effective remedy that could treat all the contaminants of concern (COC) at the site including
metals. ln Table l of the September 1992 ROD, the COCs were detennined to include Benzene,
Chloroform, 1,2,-Dichloroethane, Ethylbeozene, Chromium and Lead. The selected pwnp and
treat remedy was estimated at a present worth cost of$1.93 millio□.
The contaminated aquifer would have been remediated until the performance standards
specified in Table 1 are achieved. Figure 2 delineates the estimated periphery of the plume
emanating from the burn pit area of the New Hanover Site. Following treatment of the extracted
groundwater, the groundwater would have been discharged into a sewer connection to the
North side POTW which is owned and operated by the City of Wilmington. A sewer line exists
along tbc periincter roads to the New Hanover County Airport. ·
Three (3) extracting wells, each pumping at a rate of five (5) gpm would have been
necessary to achieve and maintain a sufficient drawdown in the underlying aquifer to contain and
remove the plume of contamination, The extraction wells would have been located within and
near the periphery of the plume. The extracted groundwater would have been treated in an
above-ground, on-site air stripper. An optional pretreatment step was planned to remove TSS
and iron to prevent fouling oft he air stripper. The necessity of a pretreatment step as well as the
number, placement, and pumping rate of the extraction wells was to be dctennined in the
Remedial Design. The air stripper was to be designed to achieve a less than I ug/1 level of
benzene in the effluent, which was a pretr~atment requirement specified by the Publicly Owned
Treatment Watcrwork (POT\V).
4
N □f<TH SUPERFUND ID: M.'1Y 15'00 11:02 No.005 P.11 •
2.2 Rationale for Changing the Selected Remedy
From the beginning of negotiations, the PRPs raised their concern over the groundwater
pump-and-treat selected remedy in the ROD because it was driven by the State of North ·
Carolina's stringent cleanup level for benzene (lppb). The PRPs requested that EPA consider
less expensive options, or in the alternative, a waiver of the groundwater cleanup standards.
Upon failure to negotiate a Consent Decree, the EPA issued a Unilateral Administrative
Order (UAO) on February 28, 1994, for pcifonnance of the remedial design and remedial action
at the site. The PRPs agreed to do the work on March 21, 1994 and selected their contractor to
prepare the Remedial Design of the groundwater treatment system. The contractor conducted
additional field activities installing monitoring wells in September and October 1994, in support
of obtaining more data to aid in development of the Remedial Design (RD).
The RD required submittal of the Remedial Design Work Plan. On May 17, 1994, the
PRPs submitted the_Remedial Design Work Plan (RDWP) which provided a detailed scope of
work and technical approach for completion of the RD set forth in the ROD, as well as a schedule
for RD completion. As required in the RDWP, a Preliminary Remedial Design report
representing a 30% submittal was submitted to EPA on December 15, 1994. EPA approved the
30% submittal un February 1995. · '
In accordance with the UAO, th~"Piu>s submitted the Intennedia,tc Design (60%
submittal) Rcpo11 to EPA on June 1, 1995. The Intermediate Design Report did not address the
remedy as outlined in the ROD. Instead, the 60 % Design submittal recommended Air Sparging
as the preferred remedy. Since the original ROD included metals contamination (inorganic
chromium and lead) as Contaminants of Concern (COCs) Air Sparging was not an appropriate
remedy.
After conferencing with the PRP's representative in the summer of 1996, low flow (low
turbidity) sampling of select monitoring wells was completed at the Site in tbc Fall of 1996 and
the results indicated no occurrence of metals was associated with the preservative leaching of
trace metals from high concentrations of solids found in previous sampling.
Since metals contamination was determined by field testing of the source area
groundwater to no longer be COCs, the PRPs requested permission to conduct a study to
evaluate current groundwater remediation technologies and their potential applicability to the
Burn Pit Site.
The remedial technology considered best for treating the Site related volatile organic
compounds (YOCs) is Air Sparging. In order to verify its effectiveness at the Bum Pit Site, an
Air Sparging TreatabiLity Study was conducted in 1998 and the results arc documented in the Air
Sparging Pilot Test TrcatabiLity Srndy Repor;t dated December 16, 1998. The Air Sparging
Treatability Study results showed air sparging to be very effective at treating the VOCs present in
I ..
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NORTH SUPERFUND ID: MAY iS'OO li:02 No.005 P.12 • •
the groundwater at the Site. A Feasibility Study Amendment (FSA) was then conducted to
document the comparison of alternatives in the original ROD with the proposed air sparging
remedy.
After signing of the ROD, the PRPs requested permission to conduct a study to determine
whether conditions at the Site satisfy the newly established requirement set forth by the Noith
Carolina Department of Environment and Natural Resources for submittal of a Con-cctivc Action
Plan (CAP) which uses Natural Attenuation or Intrinsic Bioremcdiation as the proposed
remediation approach. The CAP would be based 011 the T15A NCAC:02L.0106(1) rule. Also, the
PR.P, requested permission to conduct a study to evaluate cun-ent groundwater remediation
technologies and their potential applicabiLity to the Burn Pit Site.
After completing this study, the PRPs concluded that groundwater sampling/laboratory
analysis did not indicate a net reduction of contaminant concentration level~ over the three and
one-half year period of record. Therefore, the PRPs felt that it could not be conclusively
determined without additional data and analysis that a remediation/attenuation based CAP would
be effective under cun-ent NCDENR guidelines.
Since metals contamioatioo was no longer of concern, air sparging technology was then
considered the preferred remedy. Therefore, based on the results of the studies noted above and
guidance published by EPA, and other consultants experience with similar sites, Air Sparging is
.. consi•ctered to be a more effective a'i1d less costly alteiilative for groundwater remediation at the'
Site,,, Cos\ ass,ociated. wjth irr,iplemcntation of an air sparging system for the Bum Pit Site was
estimated to be approximately $245,000.00,
l'ump and Treat
The selected ROD remedy was pump aud treat and was chosen because it was the most
effective remedy that could treat all the contaminants of concern at the site including metals.
Following the ROD, the PRPs have submitted documentation to vclify that there is no occurrence
of metals above Federal or State standards, Therefore, metals contamination is no longer
considered a contaminant of concern. The ROD for the Site requires 9. 7 million gallons of
groundwater to be extracted, treated above ground and discharged to the City of Wilmington's
Northside POTW for a period of4.5 years, Because of the USEPA's experience with the pump-
a□d-treat approach, it is believed that a system period of operation of 4.5 years (based upon an
extracted volume of groundwater of 9. 7 million gallons) may not be realistic.
Although the pump-and-treat approach to groundwater remediation has bee□ implemented
at a variety of contaminated Sites over the past several years, it has become apparent through a site
specific treatability study and other documentation, that air sparging has the potential for a faster
and more efficient cleanup at Sites with low concentration~ of VOCs. The USEP A has confinned
that although pump-and-treat is the most commonly used technology for remediating contaminated
groundwaters, contamination reduction stops long before reaching remediation levels (cleanup
standards).
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i✓ORTH SUPERFUND ID: MAY 15'00 11:03 No.005 P.13 •
The primary reason this occurs is that chemicals have an affinity to bind to organic and
inorganic matter present in the soils of the aquifer. Chemicals also have a solubility limit in
groundwater that causes them to release from soil particles in the aquifer to the groundwater at a
rate much less than the extraction rate of the pump and treat system. Therefore, in many cases
where contaminant concentrations are near the solubility limit, pump and treat remedies are long
tenn containment remedies that take many years to reach performance standards. Hence at some
sites, such as this one, the slow rate of contaminant removal and the relative costs associated with
this type of traditional remedy are unwananted or unnecessary.
Therefore, the USEPA and the State have worked with the PRPs and their contractor to
change the remedy to Air Sparging as an alternative remedy that is a more effective and less costly
groundwater remediation alternative,
3.0 DESCRIPTION OF NEW ALTERNATIVES
Based upon consideration of the requirements of CERCLA, the NCP, and the.detailed
analysis of alternatives, EPA reviewed a total of five groundwater restoration options for this ROD
amendment to evaluate the feasibility of this option in light of new information that has been
obtained since the original ROD was finalized. Tbe alternatives were evaluated and compared to
the nine criteria, as required by the NCP. This analysis of alternatives is documented in the
Amended Feasibility Study dated June 24, 1999. A swnmary is provided below.
Alternative 1 involved containing the groundwater plume with a sluny wall. Alternatives 2-4 are
• vaiiaticins offne original remedy, which stated.that pump-and-treat iVbuld be utilized io restore ·
groundwater to levels protective of human health. Alternative 2 involved a treatment by which
the extra.cted groundwater would have consisted of chromium reduction, metals precipitation
using sodium hydroxide, flocculation, clarification and filtration; and air stripping to meet State
requirements for ultimate groundwater discharge via on-site spray i.JTigation. Alternatives 3 and 4
involved the installation of a groundwater extraction system to remove 9. 7 million gallons of
contaminated groundwater, chromium reduction and metal precipitation, and discharge of the
treated groundwater to Smith Creek or POTW. EPA Region 4 bas selected Alternative 5 (of the
focused feasibility study) as its preferred remedy which is estimated at $245,000 in present worth
cost over 4.5 years. This response action will address the contaminated groundwater by volatizing
and degrading benzene and other volatile organic compounds from the contaminated groundwater.
Alternative GWI: Vertical Barrier/Cap
This alternative involves containing the groundwater plume with. a vertical barrier (i.e.,
slurry wall) and the construction of an impenneable cap to prevent precipitation from causing
groundwater mounding within the area encompassed by the vertical barrier. The vertical barrier
would be accomplished by employing a slurry wall to a depth of approximately 30 feet. The slurry
wall would be anchored in the 5 foot blue clay layer encountered under the Site. Restrictions on
future land use would be warranted.
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i,ORTH SUPERi'UND ID: MAY 15'00 11:04 No.005 P.14 • •
Periodic sampling of the groundwater would take place in order to monitor changes in both
contaminant concentrations as well as defining the migration of the plume. The need for additional
monitoring of groundwater and the frequency of the monitoring would be resolved in the Remedial
Design (RD). ·
The capital costs include the installation of the slurry wall and the construction of the cap,
Operation & Maintenance (O&M) costs would include maintenance of the cap, periodic
groundwater sampling, and the costs for conducting the 5 year reviews as required by Section
212(c) ofCERCLA
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Peliod of Operation:
$ 925,900
$ 161,800
$1,087,700
6 months for design and contractor selection/
8 months to construct
30 years
Altern·ative GW2: Grou·nuwater Extraction and Physical/Chemical Treatment (Clironµum
Feductlon. Metals Precipitation. and Air Stripping) with Discharge via.Spray Irrlgatio!I,.,
This alternative involved the installation of a groundwater extraction system to remove the
9. 7 million gallons of contaminated groundwater, chromium reduction, metals precipitation, VOC
removal using air stripping, and on-site discharge by spray irrigation. Groundwater would be
extracted from within the plume. The point of compliance for this alternative is the e>.1ent the
plume has traveled in the aquifer where levels of contaminants arc above the cleanup goals.
The treatment train for the extracted groundwater would consist of chromium reduction;
metals precipitation using sodium hydroxide, flocculation, clarification, and filtration; and air
stripping to meet State requirements for ultimate groundwater discharge via on-site spray
irrigation.
The settled sludge from the metals removal step would be pumped to a filter press. The
sludge recovered from the dewatering operation would be recycled or analyzed and disposed off-
site at a hazardous or solid waste landfill. Following the air stripper, the treated groundwater
would then be pumped to the on-site spray irrigation system Operation of the extraction system
during wet weather or frceiing temperature conditions requires provisions for sufficient storage of
treated groundwater.
Capital Costs:
PW O&M Costs:
Total PW Costs:
9
$1,053,900
$L26s.ioo
$2,319,100
l✓lJRTH SUPERFUND ID:
e
Time to lmplemeat:
Estimated Period of Operation:
MRY 15'00 11:0S No.005 P.15 •
6 months to design and select contractor/
8 months to construct
4.5 years
Alternative GW3: Groundwater Extraction and Physical/Chemical Treatment (Chromium
Reduction and Metals Precipitation) with Discharge to Surface Water
This alternative involves the installation of a groundwater extraction system to remove the
9. 7 million gallons of contaminated grouadwater, chromium reduction and metals precipitation,
and discharge of the treated groundwater to Smith Creek located approximately 4,000 feet south
of the Site. The groundwater extraction system would be identical to that described in Alternative
2. Following the removal of the metals, the treated groundwater would be piped and discharged
into Smith Creek via an NPDES permit. The point of compliance is the same as specified in
Alternative 2.
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Peri,od ofOp.~rntions:
$I, 132,500
$1.194.500
$2,327.000
6 months for design and contractor selection
5yc.ars
Alternative GW4: Groundwater Extraction and Phni~al Treatment (Air Stripping} with
Discharge to POTW
This alternative was selected because it was the most effective remedy that could treat all
the contaminants of concern at the Site including metals. The remedy consist of the installation
of a groundwater extraction system to remove the 9, 7 million gallons of contaminated
groundwater, an air stripping step to remove the VOCs, and discharging the treated groundwater
to the Northsidc POTW which is owned and operated by the City of Wilmington, Groundwater
would be extracted from within the plume and pumped to an on-site treatment system It was
anticipated that this groundwater treatment system would achieve cleanup goals to meet the
"below detection limit" for benzene (i.e., 1.0 ug/1) requirement for discharge to the POTW,
Treated groundwater would flow from the air stripper to a sewer connection to the POTW. The
point of compliance for this alternatives was the extent the plume traveled in the aquifer.
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Period of Operations: i
$ 859,100
$1,073,700
$1,932,800
6 months for design and contractor
selection/2 months to constmct
4,5 years
10
!~ORTH SUPERFUND JD: MRY 15'00 11 : 05 No . 005 P. 16 • •
Alternatiye GWS; h1situ Groundwater Air Spargjng
This alternative includes insitu groundwater air sparging and ongoing monitoring of
groundwater contaminant levels which was documented in the Amended Feasibility Study dated
June 24, 1999. A Trcatability Study of this system was conducted between late 1997 th.rough
December 1998. The result~ of the study established that air sparging effectively reduced ·
contaminant concentrations in the groundwater at the Site, to concentrations below the detection
limit in many oftbe observation wells at the study area (Sec Figure 2).
This type of treatment concept bas been implemented with major success at sites
contaminated with VOCs and has. gained general industry acceptance in the years since the
Feasibility Study was submitted. Air is injected into the aquifer below the deepest known portion
of contamination through a strategically located network of vertically or horizontally installed air
sparging wells. The injected air diffuses through the groundwater thereby volatilizing and
enhancing degradation of the VOC contaminants dissolved in the groundwater. The contaminants
are then in vapor fonn and move into any cracks or breaks in the subsurface and are eventually
vented into the atmosphere. The Pilot Test Treatability Study at the Site consisted of installing a
sparge well in the primary source area of the plume. Air was forced into the aquifer
through the spargc well that effectively volatized and degraded the VOC contaminants. Air
Sparging is most efficient in the immediate area around the sparge well and efficiency decreases
with increased distance from the sparge well. The Treatability Study resulted in l 00% reduction of
-an VOC compounds within a radius ofl2.8 feet from the sparge well to approximately 50%
r_ed1,1,ction at a radius of 21.5 feet. ..... , , , ·
Capital Costs: $245,000.00
Time to Implement: 3 to 5 years
4.0 COMPARATIVE ANALYSIS OF NEW ALTERNATIVE REMEDIES
USEP A Region 4 has reconsidered the Selected Remedy presented in the September 1992
ROD. This section profiles Alternative 5, which the Agency is now selecting, after cornpaiing it to
the other alternatives that were evaluated, using the nine criteria as specified in the NCP.
Evaluation
4.1 Overall Protectiveness
The greatest reduction in the potential risk of groundwater ingestion and inhalation would
be achieved since all contaminated groundwater would be treated insitu to levels established by the
Record ofDeeision Amendment.
11
HORTH SUPERFUND ID: MRY 15'00 11:05 No.005 P.17 •
4.2 Compliance with ARARS
Groundwater contaminant concentrations would meet the established cleanup goals for the
New Hanover County Airport Burn Pit Site.
4.3 Long-Term Effectiveness 11nd Permanence
The potential of off-site contaminant migration via groundwater would be eliminated
permanently. The groundwater treatment system would require performance specifications to
ensure the adequate operation oflhe system. Long-term public health risks associated with
groundwater ingestion and inhalation would be eliminated. It is expected that no future site use
restrictions would be required once groundwater treatment is completed (See Table 2).
4.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Insitu treatment of contaminated groundwater would achieve a maximum and·pellTlanent
reduction of contaminant mobility, toxicity, and volume in the groundwater.
4.5 Short-Term Effectiveness
Small-scale construction activities during instaUation of sparging we Us and during air
stri/ipillg operation may result in the release ofmin'i"mal volatilized coma.rmnai:its, and the operation
of dril.lipg equipment woµJd prpduce addi~ional n9ise. Therefore, health and ~afc.:ty requirements
while implementing this alternative would include periodic monitoring of organic vapors and the
use of personal protection equipment by all personnel at the Site. Equipment and personnel
decontamination facilities would also be necessary.
4.6 Implementability
Preliminary Schedule
Approximately ~ix to nine months would be required for design and review. Assuming no
major delays, this alternative could be implemented in approximately one to two years. lnsitu
groundwater air sparging remediation would require approximately three to five years.
4.7 State Acceptance
The State of North Carolina concurs with this amendment to the 1992 ROD (sec
Appendix A).
4.8 Community Acceptance
There were no major objections to the proposed remedy during the public comment pc1iod.
The USEPA received a letter from residents ill the area requesting another thirty days extension
i
12
NORTH SUPERFUND ID: MRY 15'00 11:05 No.005 P.18 •
pending test results on the ,ampling investigation. The USEPA felt that it was necessaiy to
continue the remedial schedule as planned to implement the proposed remedy.
4.9 Cost
A comparison or present worth cost associated with the groundwater alternative indicates
that Alternative 5 is the least expensive $245,000 (see Appendix B).
5.0 STATUTORY DETERMINATlONS
Under its legal authorities, EPA's primary responsibiLity at Superfuad sites is to select
remedial actions that arc protective of human health and the environment. In addition, Section 121
ofCERCLA established several other statu\01y requi.rements and preferences. These specify that
when complete, the selected remedial action for a Site must comply with applicable or relevant and
appropriate environmental standards established under Federal and State cnviroamcntal laws unless
a statutory waiver is granted. The selected remedy must also be cost-effective and utilize
pennanent treatment technologies or resource recovery technologies to the
maximum extent practicable. Finally, the statute includes a preference for remedies that
pennanently and significantly reduce the volume, toxicity, or mobility of hazardous wastes.
Considering the new infonnatioa □ow available and the changes made to the selected
remedy by this ROD amendment, USEPA believes that the air sparging remedy will be protective
of human health apd the enviroll!l}CJJ\and complies with federal and st.ate rcquiremegts th~t were
identified in the September 1992 ROD as applicable or relevant and appropriate to this remedial
action. In addition, the revised remedy utilizes pennanent solutions and alternative treatment
technologies to the maximum extent practicable for this Site.
13
i-WRTH SUPERFUND ID: MRY 15'00 11:07 No.005 P.19 •
Table 1
GROUNDWATER REMEDIATION LEVELS
Maximum Remediation
Contaminants Concentration Level·
Detected (ppb)
(ppb)
VOLAT[LE ORGANICS
. ., "' ,,, .
Benzene 220 1
~ -~
Chlorofonn 3.4 . l 9
1,2-Dichloroethane 4.4 .38
Ethylbcnzene 120 .29
IN ORGANICS
Chromium 82 50
Lead 22 15
I
1'ADLE 2
'
SUMMARY OF INSTITUTIONAL AND LAND USE RESTRICTIONS '
NEW HANOVER COUNTY AIRPORT BURN PIT SITE
WlLMINGTON, NORTH CAROLINA
Activities
Remedial Activities Fencing"' Restrictions Land Use Development Groundwater
Use
6: Air Sparging No No No No N"
Notes:
(Ii Fencing rcstric1ions apply to the period of remediation only (c:xccpl for no action). Since Air Sparging is an insitu tcc.hnoiogy. no fencing requirement!-arc
required.
Yc.c.::::: Restrictions apply.
No ::::-No rc.c.tric1ions after rcmcdi.1tion assuming ARARs and cleanup goals a:rc rnet.
•
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C z
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0
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0
tWRTH SUPERFUND ID: MRY 15'00 11:08 No.005 P.21
APPENDIX A
State of North Carolina Concurrence Letter
I
I
NORTH SUPERFUND ID: MAY 15'00 11 : 08 No . 005 P. 22
APPENDIX B
Summary of Cost Estimates for Evaluated Alternatives
'· I
NORTH SUPERFUND ID: MRY 15'00 11:08 No.005 P.23 •
COST ESTIMATE OF AIR SPARGING BASED CORRECTIVE ACTION FOR
NEW HANOVER COUNTY AIRPORT BURNPIT SUPERFL:~!J SITE
DESCRIPTION COST
(dollars)
Remedial Design 70,000
Equipment costs for remedial action 60,000
Installation of Equipment 11 ,500
Annual operating costs to include sampling and analysis
Tum key operation by contractor or designated 20,000/yr, x S years =
subcontractor 100,000
Tota.l Present Worth Cost S24:,!;00
NORTH SUPERFUND
TO:
OFFICE:
PROM:
OFFICE:
MAY 15'00 10:57 No.005 P.01
... .. . . -~~ · -·.: \·t:. . :'.1~tL: ·: . ·· · . · ··tt\ ·• · . ·. · \'}~i United states Envlronmi-.ntal ~otection Agency-" 5,
Waste Management Division · · • I
North Site Management Branch
61 Fo~ Street, SW
Atlailta, Georgia 30303
'I'ELEPHONE I:
-2.,f ~
RETUR.i.~ FAX#: [phone]
• •
D ~ fE ~ w [~ ;r(·
DEC 8 21JOO ~
SUPERFUND SECTION
NEW HANOVER COUNTY AIRPORT BURN PIT
SUPERFUND SITE
AMENDED RECORD OF DECISION
·MARCH2000
United States Environmental Protection Agency
Region 4
• •
TABLE OF CONTENTS
Section Page
THE DECLARATION ....................................................... I
DECISION SUMMARY ...................................................... 1
1.0 INTRODUCTION ..................................................... 1
1.1 Site Location ........................................................ 1
1.2 Affected Population .................................................... I
1.3 Adjacent Land Uses .................................................... 1
1 .4 Natural Resources ..................................................... 1
1.5 Site Operational History ................................................. 2
1.6 Highlights of Community Participation ...................................... 3
2.0 REASONS FOR ISSUING THE ROD AMENDMENT ........................ 4
2.1 · Description of Original Selected Remedy .................................... 4
2.2 Rationale for Changing New Selected Remedy ................................ 6
3.0 DESCRIPTION OF NEW ALTERNATIVES ................................ 8
4.0 COMPARATIVE ANALYSIS OF NEW ALTERNATIVE REMEDIES ........... 11
4.1 Overall Protection of Human Health and the Environment ...................... 11
4.2 Compliance with ARARS ............................................... 12
4.3 Long-Term Effectiveness and Permanence .................................. 12
4.4 Reduction of Toxicity, Mobility or Volume through Treatment .................. 12
4.5 Short-Term Effectiveness ............................................... 12
4.6 Implementability ...................................................... 12
4.7 State Acceptance ..................................................... 12
4.8 Community Acceptance ................................................ 12
4.9 Cost ............................................................... 13
5.0 STATUTORY DETERMINATIONS ..................................... 13
List of Figures
Figure 1 Site Location Map ................................................... 2
Figure 2 Estimated Extent of Concentrations in Groundwater .......................... 5
List of Tables
Table I -Groundwater Remediation Levels
Table 2 -Institutional and Land Use Restrictions
APPENDICES
•
Appendix A -North Carolina Division of Superfund Letter of Concurrence
Appendix B -Summary of Cost Estimates for Evaluated Alternatives
• •
AMENDED RECORD OF DECISION
THE DECLARATION
Site Name and Location
New Hanover County Airport Bum Pit
Wilmington, Brunswick County, North Carolina
Statement of Basis and Purpose
' \ --·
This decision descnbes a fundamental change to the groundwater restoration approach
presented in the Record of Decision (ROD) of the New Hanover County Airport Bum Pit Site
(the Site). As the result of information developed since the original ROD was finalized, the
United States Environmental Protection Agency (USEPA) has decided to choose air sparging as
the new Selected Remedy for groundwater. This change to the original Selected Remedy was
chosen in accordance with Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA), as amended, and to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan.
EPA has determined that all soil remediation has been completed at the Site. Site-specific
data obtained prior to the ROD indicated the aquifer or groundwater plume flowing beneath and
down gradient of the Site pose a threat to human health or the environment. Although
contaminant levels and risk to human health now appear to be minimal for this site, during a
recent study of site conditions it could not be conclusively determined that natural attenuation of
contaminants in groundwater is occurring. Therefore, active groundwater remediation options
have been reevaluated for this Site to achieve groundwater clean-up goals. Based on a site-
specific feasibility study and documents published by the USEP A for sites similar to the Bum Pit
Site, air sparging appears to be a remedial treatment alternative which is technically and
economically superior to the previously selected pump-and-treat alternative.
The State of North Carolina concurs with this amendment to the ROD (See concurrence
letter Appendix A).
Rational For Selection of Air Sparging As Groundwater Restoration Remedy
Air Sparging
Air sparging remediation technology has been implemented with success at sites
contaminated with Volatile Organic Compounds (VOCs) and has gained general industry
acceptance in the last few years. It is one of the groundwater remedial technologies that the
USEPA has proposed for consideration at Superfund Sites because of its potential for providing a
faster, more effective and less costly alternative to traditional cleanup methods, such as purnp-
and-treat. · ·
• •
Even though a pump-and-treat remedy was selected in the September 29, 1992 ROD as
the preferred remedy, air sparging technologies offer a number of other advantages over the
pump-and-treat approach. These advantages have been documented by the USEP A and include:
• The potential to substantially decrease the time required to achieve remedial goals,
• Readily available equipment and easy installation,
• Requires no extraction, treatment, storage or discharge considerations for groundwater.
Further, metal contaminants are being deleted from the original ROD as Contaminants of
Concern (COC); Several sampling investigations using low flow (low turbidity) sampling were
completed by the Potential Responsible Panies (PRPs) and the results indicated that metal
contaminants were not present above Federal and State standards. Therefore, metals _did not
require remediation and the air sparging technology was then considered as an available
remediation technology.
Statutory Determination
Considering the new information that has been developed and the changes that have been
made to the Selected Remedy, USEPA believes that the remedy remains protective of human
health and the environment and complies with Federal and State requirements that were identified
in the September 29, 1992 ROD, as applicable or relevant and appropriate to this remedial action
at the time the original ROD was signed. The air sparging remedy satisfies the statutory
preference for treatment as a principle element because it restores the shallow aquifer beneath the
Site.
Upon completion of this remedy, no hazardous or toxic substances are expected to remain
on-site above health based levels that prevent unlimited use and unrestricted exposure. However,
it is expected that it may take five years to achieve the clean-up goals. Therefore, a Five Year
Review will be conducted within five years of completion of the Preliminary Close-Out Repon.
Richard D. Green, Director
Waste Management Division
•
Decision Summary
1.0 SITE NAME, LOCATION, AND DESCRIPTiON
I. 1 Site Location
The New Hanover County Bum Pit Superfund Site is located on Gardner Drive, 500 feet west of the New Hanover County Airport in New Hanover County, approximately 1.5 miles north
of Wilmington, North Carolina as shown in Figure I.
The approximately 1,500 square 'foot bum pit was located near the center of a four-acre
plot (see Figure 2) on the New Hanover County Airport property.
1.2 Affected Population
The closest residential area to the Site is approximately 0.22 miles to the west of the Site.
This area is separated from the Site by a road, railroad tracks, and a wooded area. The plume of volatile organic compounds (VOCs) does not affect off-site residential or industrial populations
since the known plume does not extend more than 350 feet from the location of the original hum
pit.
1.3 Land Use
Land use in the vicinity is commercial, light industrial, and residential. There are rental car
maintenance facilities, a closed sawmill/lumberyard, and a trucking company to the east and
northeast of the Site. The closest residential areas to the Site are approximately 0.22 miles to the west of the Site. This area is separated from the Site by a road, railroad tracks, and a wooded
area.
The land immediately northeast, north, west, and south of the Site is forested with mixed southern hardwoods typical of the coastal plain area. This wooded area extends for
approximately 300 to 500 feet west and north and 800 feet south of the Site.
1.4 Natural Resources
The groundwater under the Site is designated as Class GA in accordance with North
Carolina's groundwater classification system and Class IIB under USEP A Groundwater
Classification Guidelines (December 1986). The Class GA classification means that the
groundwater is an existing or potential source of drinking water supply for humans as defined in
•
Title 15A, North Carolina Administrative Code, Subchapter 2L (TISA NCAC 2L). EPA
classifies the upper zone of the aquifer (i.e., the groundwater above of the blue clay layer) as Class
IIB since the aquifer is of drinking quality but is. not currently being used as a source of drinking
water. The groundwater beneath the blue clay layer is assumed to be interconnected with the
Castle Hayne Limestone formation and is therefore, classified as IIA. Class IIA is defined as an
aquifer that is currently being used as a drinking water source. For these reasons, the
groundwater needs to be remediated to a level protective of public health and the environment as
specified in federal and state regulations governing the quality and use of drinking water. Both
the Pee Dee and the Castle Hayne are major drinking water sources for New Hanover County.
1.5 Site Operational History
The New Hanover County Airport Bum Pit was constructed by the County of New
Hanover in 1968. From 1968 to 1979, the Cape Fear Technical Institute (now known as the Cape
Fear Community College), used the bum pit for fire-training purposes, burning jet fuel and
gasoline in the bum pit, and extinguishing the fires with water. The Wilmington Fire Department
used the bum pit for fire-training purposes from 1968 to 1976 and the United States Air Force
used the bum pit for fire-training purposes during the Vietnam War.
Jet fuel and drainage from petroleum fuel storage tanks in the area were burned, and the
fires were extinguished with water, carbon dioxide, and dry chemicals. Some time prior to 1982,
materials used in river spill cleanups were dumped into the bum pit.
In 1986, the North Carolina Division of Health Services discovered heavy metals and
numerous organics in the soil around the bum pit and in other nearby soil samples. Surface water
within three (3) miles downstream of the Site is used for recreational activities, and an estuary
wetland is located approximately one (I) mile from the Site. Approximately 6,300 people obtain
drinking water from public and private wells within three (3) miles of the Site. A private well is
located approximately 1,500 feet to the northwest of the Site.
To date, EPA has identified four ( 4) potentially responsible parties (PRPs) at the Site: the
County of New Hanover, North Carolina; the City of Wilmington, North Carolina; the Cape Fear
Community College; and the United States Air Force.
The Site was listed on the National Priorities List on March 31, 1989. EPA negotiated
with the three (3) municipal PRPs in March 1989, for performance of the remedial
investigation/feasibility study (Rl/FS), but the parties were unable to reach an agreement. In May
1990, however, the parties signed an Administrative Order on Consent for a removal action.
During the removal, the PRPs removed all of the source material present at the Site at a cost of
$452,500.00.
2
•
EPA conducted a fund-lead RI/FS in 1991 and 1992, and issued a Record of Decision
(ROD) for the Site on September 29, 1992. The ROD contemplated pump-and-treat of the
groundwater to address low levels of benzene, ethyl benzene, lead, and chromium at an estimated
present worth cost of $1.5 million.
As part of the selected remedy, the ROD included a technical impracticability provision
and provided for an additional year of groundwater sampling for EPA to determine whether or
not natural attenuation was occurring in the groundwater. After six (6) rounds of sampling
conducted by EPA's Ecological Science Division , there was no evidence that natural attenuation
was occurring with any of the contaminants currently present in the groundwater.
1.6 Highlights of Community Participation
In accordance with CERCLA, Section 117 and the National Contingency Plan (NCP)
300.435(c)(2)(ii) a revised proposed plan was mailed to interested parties and other persons who
have requested to be included on USEP A's mailing list for the Site. The proposed plan
supporting information was made available to the public in the information repository maintained
at the EPA Docket Room in Atlanta and at the New Hanover Public Library located at 210
Chestnut Street, Wilmington, North Carolina. Notice of availability of these documents were
published in Wilmington Morning Star on November I, 1999.
The USEPA conducted a public meeting on November 30, 1999. A comment period of
sixty days was provided to receive written or oral comments from the public from November 16,
1999 to January 15, 2000. At the public meeting, many residents were concerned about their
drinking water and surface water run-off. The citizens requested the USEP A to sample their
wells and to determine if run-off from the Site and the contamination in the groundwater from the
Site had impacted their well water. Based on these concerns, the USEPA's Environmental
Services Division sampled the wells in the vicinity of the Site during the week of January 17,
2000. Results of this sampling event are expected in April 2000.
In response to comments at the public meeting, the NCDENR Superfund Section, county
officials and their consultants, and NCDENR Surface Water Quality personnel, completed
reconnaissance of the on-site and adjacent surface water pathways on January 13, 2000. On
January 21, 2000, NCDENR Surface Water Quality, Wihnington Regional Office, completed
surface water sampling in the areas agreed to by the North Carolina Supei:fund Section and the
Potentially Responsible Parties (PRPs) during the reconnaissance on January 13, 2000.
NCDENR Surface Water Quality collected another set of surface water samples on
February 3, 2000. A NCDENR Superfund Section representative and three residents from the
area were present during all or part of the surface water sampling event and observed sampling
locations and procedures. One of the four surface water samples collected on February 3, 2000
3
• •
was at a different location than the 13 January sampling event. This change was made due to
recommendations from the local residents. The preliminary results from both sampling events
indicate no detection of any COCs or VOCs.
Only one written comment was received during the 60 day public comment period. A
letter was submitted by residents requesting another thirty days extension pending test results on
the sampling investigation. Since the preliminary results from the surface water samples indicated
no detection of any COCs or VOCs, and since any additional private well sampling results would ·
not impact treatment decisions at the bum pit, the USEP A felt that it was necessary to continue
the remedial schedule as planned to implement the proposed remedy.
2.0 REASONS FOR ISSUING THE ROD AMENDMENT
2.1 Description of the Original Selected Remedy
The groundwater remediation alternative originally selected for the New Hanover Site is
Alternative GW#3 -Groundwater Extraction and Physical Treatment (Air Stripping) with
Discharge to Publicly Owned Treatment Waterworks (POTW). A description of the original
selected remedial alternative follows.
The selected ROD remedy was pump and treat and was chosen because it was the most
effective remedy that could treat all the contaminants of concern (COC) at the site including
metals. In Table I of the September 1992 ROD, the COCs were determined to include Benzene,
Chloroform, 1,2,-Dichloroethane, Ethylbenzene, Chromium and Lead. The selected pump and
treat remedy was estimated at a present worth cost of $1.93 million.
The contaminated aquifer would have been remediated until the performance standards
specified in Table I are achieved. Figure 2 delineates the estimated periphery of the plume
emanating from the bum pit area of the New Hanover Site. Following treatment of the extracted
groundwater, the groundwater would have been discharged into a sewer connection to the
N orthside POTW which is owned and operated by the City of Wilmington. A sewer line exists
along the perimeter roads to the New Hanover County Airport. ·
Three (3) extracting wells, each pumping at a rate of five (5) gpm would have been
necessary to achieve and maintain a sufficient drawdown in the underlying aquifer to contain and
remove the plume of contamination. The extraction wells would have been located within and
near the periphery of the plume. The extracted groundwater would have been treated in an
above-ground, on-site air stripper. An optional pretreatment step was planned to remove TSS
and iron to prevent fouling of the air stripper. The necessity of a pretreatment step as well as the
number, placement, and pumping rate of the extraction wells was to be determined in the
Remedial Design. The air stripper was to be designed to achieve a less than I ug/1 level of
benzene in the effluent, which was a pretreatment requirement specified by the Publicly Owned
Treatment Waterwork (POTW).
4
•
2.2 Rationale for Changing the Selected Remedy
From the beginning of negotiations, the PRPs raised their concern over the groundwater
pump-and-treat selected remedy in the ROD because it was driven by the State of North
Carolina's stringent cleanup level for benzene (lppb). The_PRPs:requested that EPA consider
less expensive options, or in the alternative, a waiver of the \i~~undwater cleanup standards.
Upon failure to negotiate a Consent Decree, the EPA issued a Unilateral Administrative
Order (UAO) on February 28, 1994, for performance of the remedial design and remedial action
at the site. The PRPs agreed to do the work on March 21, 1994 and selected their contractor to
prepare the Remedial Design of the groundwater treatment system The contractor conducted
additional field activities installing monitoring wells in September and October 1994, in support
of obtaining more data to aid in development of the Remedial Design (RD).
The RD required submittal of the Remedial Design Work Plan. On May 17, 1994, the
PRPs submitted the Remedial Design Work Plan (RDWP) which provided a detailed scope of
work and technical approach for completion of the RD set forth in the ROD, as well as a schedule
for RD completion. As required in the RDWP, a Preliminary Remedial Design report
representing a 30% submittal was submitted to EPA on December 15, 1994. EPA approved the
30% submittal on February 1995.
In accordance with the UAO, the PRPs submitted the Intermediate Design (60%
submittal) Report to EPA on June 1, 1995. The Intermediate Design Report did not address the
remedy as outlined in the ROD. Instead, the 60 % Design submittal recommended Air Sparging
as the preferred remedy. Since the original ROD included metals contamination (inorganic
chromium and lead) as Contaminants of Concern (COCs) Air Sparging was not an appropriate
remedy.
After conferencing with the PRP's representative in the summer of 1996, low flow (low
turbidity) sampling of select monitoring wells was completed at the Site in the Fall of 1996 and
the results indicated no occurrence of metals was associated with the preservative leaching of
trace metals from high concentrations of solids found in previous sampling.
Since metals contamination was determined by field testing of the source area
groundwater to no longer be COCs, the PRPs requested permission to conduct a study to
evaluate current groundwater remediation technologies and their potential applicability to the
Bum Pit Site.
The remedial technology considered best for treating the Site related volatile organic
compounds (VOCs) is Air Sparging. In order to verify its effectiveness at the Bum Pit Site, an
Air Sparging Treatability Study was conducted in 1998 and the results are documented in the Air
Sparging Pilot Test Treatability Study Report dated December 16, 1998. The Air Sparging
_ Treatability Study results showed air sparging to be very effective at treating the VOCs present in
6
•
the groundwater at the Site. A Feasibility Study Amendment (FSA) was then conducted to
document the comparison of alternatives in the original ROD with the proposed air sparging
remedy.
After signing of the ROD, the PRPs requested permission to conduct a study to determine
whether conditions at the Site satisfy the newly established requirement set forth by the North
Carolina Department of Environment and Natural Resources for submittal of a Corrective Action
Plan (CAP) which uses Natural Attenuation or Intrinsic Bioremediation as the proposed
remediation approach. The CAP would be based on the Tl5A NCAC:02L.0106(1) rule. Also, the
PRPs requested permission to conduct a study to evaluate current groundwater remediation
technologies and their potential applicability to the Burn Pit Site.
After completing this study, the PRPs concluded that groundwater sampling/laboratory
analysis did not indicate a net reduction of contaminant concentration levels over the three and
one-half year period ofrecord. Therefore, the PRPs felt that it could not be conclusively
determined without additional data and analysis that a remediation/attenuation based CAP would
be effective under current NCDENR guidelines.
Since metals contamination was no longer of concern, air sparging technology was then
considered the preferred remedy. Therefore, based on the results of the studies noted above and
guidance published by EPA, and other consultants experience with similar sites, Air Sparging is
considered to be a more effective and less costly alternative for groundwater remediation at the
Site. Cost associated with implementation of an air sparging system for the Burn Pit Site was
estimated to be approximately $245,000.00.
Pump and Treat
The selected ROD remedy was pump and treat and was chosen because it was the most
effective remedy that could treat all the contaminants of concern at the site including metals.
Following the ROD, the PRPs have submitted documentation to verify that there is no occurrence
of metals above Federal or State standards. Therefore, metals contamination is no longer
considered a contaminant of concern. The ROD for the Site requires 9.7 million gallons of
groundwater to be extracted, treated above ground and discharged to the City of Wilmington's
Northside POTW for a period of 4.5 years. Because of the USEPA's experience with the pump-
and-treat approach, it is believed that a system period of operation of 4.5 years (based upon an
extracted volume of groundwater of9.7 million gallons) may not be realistic.
Although the pump-and-treat approach to groundwater remediation bas been implemented
at a variety of contaminated Sites over the past several years, it bas become apparent through a site
specific treatability study and other documentation, that air sparging has the potential for a faster
and more efficient cleanup at Sites with low concentrations ofVOCs. The USEPA has confirmed
that although pump-and-treat is the most commonly used technology for remediating contaminated
groundwaters, contamination reduction stops long before reaching remediation levels ( cleanup
standards).
7
•
The primary reason this occurs is that chemicals have an affinity to bind to organic and
inorganic matter present in the soils of the aquifer. Chemicals also have a solubility limit in
groundwater that causes them to release from soil particles in the aquifer to the groundwater at a
rate much less than the extraction rate of the pump and treat system Therefore. in many cases
where contaminant concentrations are near the solubility limit, pump and treat remedies are long
term containment remedies that take many years to reach performance standards. Hence at some
sites, such as this one, the slow rate of contaminant removal and the relative costs associated with
this type of traditional remedy are unwarranted or unnecessary.
Therefore, the USEP A and the State have worked with the PRPs and their contractor to
change the remedy to Air Sparging as an alternative remedy that is a more effective and less costly
groundwater remediation alternative.
3.0 DESCRIPTION OF NEW ALTERNATIVES
Based upon consideration of the requirements ofCERCLA, the NCP, and the detailed
analysis of alternatives, EPA reviewed a total of five groundwater restoration options for this ROD
amendment to evaluate the feasibility of this option in light of new information that has been
obtained since the original ROD was finalized. The alternatives were evaluated and compared to
the nine criteria, as required by the NCP. This analysis of alternatives is documented in the
Amended Feasibility Study dated June 24, 1999. A summary is provided below.
Alternative I involved containing the groundwater plume with a slurry wall. Alternatives 2-4 are
variations of the original remedy, which stated that pump-and-treat would be utilized to restore
groundwater to levels protective of human health. Alternative 2 involved a treatment by which
the extracted groundwater would have consisted of chromium reduction, metals precipitation
using sodium hydroxide, flocculation, clarification and filtration; and air stripping to meet State
requirements for ultimate groundwater discharge via on-site spray irrigation. Alternatives 3 and 4
involved the installation ofa groundwater extraction system to remove 9.7 million gallons of
contaminated groundwater, chromium reduction and metal precipitation, and discharge of the
treated groundwater to Smith Creek or POTW. EPA Region 4 has selected Alternative 5 ( of the
focused feasibility study) as its preferred remedy which is estimated at $245,000 in present worth
cost over 4.5 years. This response action will address the contaminated groundwater by volatizing
and degrading benzene and other volatile organic compounds from the contaminated groundwater.
Alternative GWI: Vertical Barrier/Cap
This alternative involves containing the groundwater plume with a vertical barrier (i.e.,
slurry wall) and the construction of an impermeable cap to prevent precipitation from causing
groundwater mounding within the area encompassed by the vertical barrier. The vertical barrier
would be accomplished by employing a slurry wall to a depth of approximately 30 feet. The slurry
wall would be anchored in the 5 foot blue clay layer encountered under the Site. Restrictions on
future land use would be warranted.
8
• •
Periodic sampling of the groundwater would take place in order to monitor changes in both
contaminant concentrations as well as defining the migration of the plume. The need for additional
monitoring of groundwater and the frequency of the monitoring would be resolved in the Remedial
Design (RD).
The capital costs include the installation of the slurry wall and the construction of the cap.
Operation & Maintenance (O&M) costs would include maintenance of the cap, periodic
groundwater sampling, and the costs for conducting the 5 year reviews as required by Section
212(c) ofCERCLA. .
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Period of Operation:
$ 925,900
$ 161,800
$1,087,700
6 months for design and contractor selection/
8 months to construct
30 years
Alternative GW2: Groundwater Extraction and Physical/Chemical Treatment (Chromium
Reduction, Metals Precipitation, and Air Stripping) with Discharge via Spray Irrigation
This alternative involved the installation of a groundwater extraction system to remove the
9.7 million gallons of contaminated groundwater, chromium reduction, metals precipitation, VOC
removal using air stripping, and on-site discharge by spray irrigation. Groundwater would be
extracted from within the plume. The point of compliance for this alternative is the extent the
plume has traveled in the aquifer where levels of contaminants are above the cleanup goals.
The treatment train for the extracted groundwater would consist of chromium reduction;
metals precipitation using sodium hydroxide, flocculation, clarification, and filtration; and air
stripping to meet State requirements for ultimate groundwater discharge via on-site spray
irrigation.
The settled sludge from the metals removal step would be pumped to a filter press. The
sludge recovered from the dewatering operation would be recycled or analyzed and disposed off-
site at a hazardous or solid waste landfill. Following the air stripper, the treated groundwater
would then be pumped to the on-site spray irrigation system. Operation of the extraciion system
during wet weather or freezing temperature conditions requires provisions for sufficient storage of
treated groundwater.
Capital Costs:
PW O&M Costs:
Total PW Costs:
9
$1,053,900
$1,265,200
$2,319,100
Time to Implement:
Estimated Period of Operation:
•
6 months to design and select contractor/
8 months to construct
4.5 years
Alternative GW3: Groundwater Extraction and PhysicaVChemical Treatment (Chromium
Reduction and Metals Precipitation) with Discharge to Surface Water
This alternative involves the installation of a groundwater extraction system to remove the
9. 7 million gallons of contaminated groundwater, chromium reduction and metals precipitation,
and discharge of the treated groundwater to Smith Creek located approximately 4,000 feet south
of the Site. The groundwater extraction system would be identical to that described in Alternative
2. Following the removal .of the metals, the treated groundwater would be piped and discharged
into Smith Creek via an NPDES permit. The point of compliance is the same as specified in
Alternative 2.
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Period of Operations:
$1,132,500
$1,194.500
$2,327,000
6 months for design and contractor selection
5 years
Alternative GW4: Groundwater Extraction and Phvsical Treatment (Air Stripping) with
Discharge to POTW
This alternative was selected because it was the most effective remedy that could treat all
the contaminants of concern at the Site including metals. The remedy consist of the installation
of a groundwater extraction system to remove the 9. 7 million gallons of contaminated
groundwater, an air stripping step to remove the VOCs, and discharging the treated groundwater
to the Northside POTW which is owned and operated by the City of Wilmington. Groundwater
would be extracted from within the plume and pumped to an on-site treatment system It was
anticipated that this groundwater treatment system would achieve cleanup goals to meet the
"below detection limit" for benzene (i.e., 1.0 ug/1) requirement for discharge to the POTW.
Treated groundwater would flow from the air stripper to a sewer connection to the POTW. The
point of compliance for this alternatives was the extent the plume traveled in the aquifer.
Capital Costs:
PW O&M Costs:
Total PW Costs:
Time to Implement:
Estimated Period of Operations:
$ 859,100
$1,073,700
$1,932,800
6 months for design and contractor
selection/2 months to construct
4.5 years
10
• •
Alternative GW5: Insitu Groundwater Air Sparging
This alternative includes insitu groundwater air sparging and ongoing monitoring of
groundwater contaminant levels which was documented in the Amended Feasibility Study dated
June 24, 1999. A Treatability Study of this system was conducted between late 1997 through
December 1998. The results of the study established that air sparging effectively reduced
contaminant concentrations in the groundwater at the Site, to concentrations below the detection
limit in many of the observation wells at the study area (See Figure 2).
This type of treatment concept has been implemented with major success at sites
contaminated with VOCs and has gained general industry acceptance in the years since the
Feasibility Study was submitted. Air is injected into the aquifer below the deepest known ponion
of contamination through a strategically located network of venically or horizontally installed air
sparging wells. The injected air diffuses through the groundwater thereby volatilizing and
enhancing degradation of the VOC contaminants dissolved in the groundwater. The contaminants
are then in vapor form and move into any cracks or breaks in the subsurface and are eventually
vented into the atmosphere. The Pilot Test Treatability Study at the Site consisted of installing a
sparge well in the primary source area of the plume. Air was forced into the aquifer
through the sparge well that effectively volatized and degraded the VOC contaminants. Air
Sparging is most efficient in the immediate area around the sparge well and efficiency decreases
with increased distance from the sparge well. The Treatability Study resulted in I 00% reduction of
all VOC compounds within a radius of 12.8 feet from the sparge well to approximately 50%
reduction at a radius of 21.5 feet.
Capital Costs: $245,000.00
Time to Implement: 3 to 5 years
4.0 COMPARATIVE ANALYSIS OF NEW ALTERNATIVE REMEDIES
USEP A Region 4 has reconsidered the Selected Remedy presented in the September 1992
ROD. This section profiles Alternative 5, which the Agency is now selecting, after comparing it to
the other alternatives that were evaluated, using the nine criteria as specified in the NCP.
Evaluation
4.1 Overall Protectiveness
The greatest reduction in the potential risk of groundwater ingestion and inhalation would
be achieved since all contaminated groundwater would be treated insitu to levels established by the
Record of Decision Amendment.
11
• •
4.2 Compliance with ARARS
Groundwater contaminant concentrations would meet the established cleanup goals for the
New Hanover County Airport Burn Pit Site.
4.3 Long-Term Effectiveness and Permanence
The potential of off-site contaminant migration via grciugdwater would be eliminated
pennanently. The groundwater treatment system would require perfonnance specifications to
ensure the adequate operation of the system Long-term public health risks associated with
groundwater ingestion and inhalation would be eliminated. It is expected that no future site use
restrictions would be required once groundwater treatment is co'mpleted (See Table 2).
' I_,'
4.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Insitu treatment of contaminated groundwater would achieve a maximum and pennanent
reduction of contaminant mobility, toxicity, and volume in the groundwater.
4.5 Short-Term Effectiveness
Small-scale construction activities during installation of sparging wells and during air
stripping operation may result in the release of minimal volatilized contaminants, and the operation
of drilling equipment would produce additional noise. Therefore, health and safety requirements
while implementing this alternative would include periodic monitoring of organic vapors and the
use of personal protection equipment by all personnel at the Site. Equipment and personnel
decontamination facilities would also be necessary.
4.6 Implementability
Preliminary Schedule
Approximately six to nine months would be required for design and review. Assuming no
major delays, this alternative could be implemented in approximately one to two years. Insitu
groundwater air sparging remediation would require approximately three to five years.
4.7 . State Acceptance
The State of North Carolina concurs with this amendment to the 1992 ROD (see
Appendix A).
4.8 Community Acceptance
There were no major objections to the proposed remedy during the public comment period.
The USEP A received a letter from residents in the area requesting another thirty days extension
12
•
pending test results on the sampling investigation. The USEPA felt that it was necessary to
continue the remedial schedule as planned to implement the proposed remedy.
4.9 Cost
A comparison or present worth cost associated with the groundwater alternative indicates
that Alternative 5 is the least expensive $245,000 (see Appendix B).
5.0 STATUTORYDETERMINATIONS
Under its legal authorities, EPA's primary responsibility at Superfund sites is to select
remedial actions that are protective of human health and the environment. In addition, Section 121
of CERCLA established several other statutory requirements and preferences. These specify that
when complete, the selected remedial action for a Site must comply with applicable or relevant and
appropriate environmental standards established under Federal and State environmental laws unless
a statutory waiver is granted. The selected remedy must also be cost-effective and utilize
permanent treatment technologies or resource recovery technologies to the
maximum extent practicable. Finally, the statute includes a preference for remedies that
permanently and significantly reduce the volume, toxicity, or mobility of hazardous wastes.
Considering the new information now available and the changes made to the selected
remedy by this ROD amendment, USEPA believes that the air sparging remedy will be protective
of human health and the environment and complies with federal and state requirements that were
identified in the September 1992 ROD as applicable or relevant and appropriate to this remedial
action. In addition, the revised remedy utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable for this Site.
13
•
pending test results on the sampling investigation. The USEP A felt that it was necessary to
continue the remedial schedule as planned to implement the proposed remedy.
4.9 Cost
A comparison or present worth cost associated with the groundwater alternative indicates
that Alternative 5 is the least expensive $245,000 (see Appendix B).
5.0 STATUTORY DETERMINATIONS
Under its legal authorities, EPA's primary responsibility at Superfund sites is to select
remedial actions that are protective of human health and the environment. In addition, Section 121
of CERCLA established several other statutory requirements and preferences. These specify that
when complete, the selected remedial action for a Site must comply with applicable or relevant and
appropriate environmental standards established under Federal and State environmental laws unless
a statutory waiver is granted. The selected remedy must also be cost-effective and utilize
permanent treatment technologies or resource recovery technologies to the
maximum extent practicable. Finally, the statute includes a preference for remedies that
permanently and significantly reduce the volume, toxicity, or mobility of hazardous wastes.
Considering the new information now available and the changes made to the selected
remedy by this ROD amendment, USEPA believes that the air sparging remedy will be protective
of human health and the environment and complies with federal and state requirements that were
identified in the September 1992 ROD as applicable or relevant and appropriate to this remedial
action. In addition, the revised remedy utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable for this Site.
B. Hudson P. Vorsatz R. Jourdan M. Tucker R. Green
13
'JAMES 8. HUNT JR.
GOVCRNOR
BILL HOLMAN
SECRETARY
,•!''. -
. ·:.-~ ...:~:.: _\_·.
RoD
NOR.CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WASTE MANAGEMENT
Ms. Beverly Hudson
North Superfund Remedial Branch
US EPA Region IV
March 30, 2000
61 Forsyth Street, Eleventh (JI) Floor
Atlanta, Georgia 30303
RE: State Concurrence with the Amendment to the Record of Decision
Groundwater Remediation
--New Hanover County Airport Burn Pit
NCD 981 021 157
Wilmington, New Hanover County, NC
Dear Ms. Hudson:
The State of North Carolina has reviewed the Amendment to the Record
of Decision (ROD) for the Ground Water Remediation of the New Hanover
County Airport Burn Pit, dated 30 March 2000. We concur with the selected
remedy, subject to the following conditions.
I. Since remediation of the soil at the subject Site was completed in 1989 and the
groundwater is expected to meet State and federal cleanup levels within three
to five years, the State does not foresee long-term groundwater contamination
that would prevent unrestricted use of the property. Therefore, the State does
not require· deed recordation or restrictions in accordance with NCGS 130A-
310.8, Recordation of inactive hazardous substances or waste disposal sites.
2. State concurrence with this Amended Record of Decision (ROD) and the
newly selected remedy for the Site is based solely on the information
contained in the Amended ROD. Should the State receive new or additional
information which significantly affects the conclusions or remedy selection
contained in the Amended ROD, it may modify or withdraw this concurrence
by giving written notice to USEPA Region IV.
3. State concurrence on this Amended Record of Decision (ROD) in no way
binds the State to concur in future decisions or commits the State to
participate, financially or otherwise, in the clean up of the site. The State
reserves the right to review, overview, comment, and make independent
assessment of all future work relating to this site.
Wiii NM·ltAW·N
1646 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699•1646
401 OBERLIN ROAD, SUITE 150, RALEIGH, NC 27605
PHONE 919-733·4996 FAX 9 \ 9•71 5-3605
AN EQUAL OPPORTUNITY/ AFFIRMATIVE ACTION EMPLOYER• 50% RECYCLED/10% POST•CONSUMER PAPER
Ms. Beverly Hudson
30 March 2000
Page 2
•
4. Although residual contamination is not expected to remain in groundwater after remediation
is complete, if the total residual risk level to human health exceeds 10-6, the State may require
deed recordation/restriction to document the presence of residual contamination and possibly
limit future use of the property as specified in NCGS 130A-310.8.
The State of North Carolina appreciates the opportunity to help amend the Record of Decision
(ROD) for the subject site, and we look forward to working with the EPA on the final remedy. If
you have any questions or comments, please give me a call at, [phone], extension 291.
cc: Phil Vorsatz, Chief, North Superfund Remedial Branch
Jack Butler, Chief, NC Superfund Section
Randy McElveen, NC Superfund Section
Sincerely, }_)4 _
1
.
v-c.-..---
ver Nicholson, Head
Federal Remediation Branch
NC Superfund Section
New Hanover ROD amendment •
I of I
Subject: New Hanover ROD amendment
Date: Fri, 18 Feb 2000 16:04 -0500 (EST)
From: [e-mail]
To: [e-mail], [e-mail],
[e-mail]
Hi Randy,
Thank you for taking the time out of your busy schedule to review the
revised ROD amendment for the New Hanover County Burn Pit Site. We
appreciate your comments. As Ciscussed by telephone on Feb.17th,
comments 4,7,9,11,13,16,17,19&20 will be incorporated into the
document. Attached please find the final revised copy. Again, thanks
for your assistance.
Beverly
Orodame~ I .doc
Name: rodame~l.doc
Type: Winword File (APPLICATION/MSWORD)
Encoding: X-UUENCODE
Description: rodame~l.doc 02/18/00 3:30P
Download Status: Not downloaded with message
2/28/2000 12:38 PM
I of I
file:///Untitled
Dear Beverly,
Hope you are enjoying the nice sunny weather lately. I have a few additional changes on the ROD
Amendment. We feel that these changes will make the document read better or are fundamental to the
ROD Amendment process and documentation. The States comments are in bold print as before. The
rest of the document is fine. If you will make these last changes as provided in this attached copy of the
ROD Amendment and email us the final version, the State will forward a concurrence letter to the EPA
for insertion into the Appendix of the document. Please have someone proof-read the document one last
time. There were some problems in the conversion process from MS Word to Word Perfect. I'll give
you a call and discuss the changes requested. Thanks, Randy
***************************************************
W. Randy McElveen,
NC Department of Environment and Natural Resources
401 Oberlin Road, suite 150
Raleigh, North Carolina 27605
[phone] ext. 341
[e-mail]
( not case sensitive)
+Please note that my email address has changed+
"He is no fool who gives what he cannot keep to gain what he cannot
lose."
Jim Elliot, THE SHADOW OF THE ALMIGHTY
****************************************************
3/2/2000 2:27 PM
NORTH IROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WASTE MANAGEMENT
November 18, 1999
RE: Comments on the Proposed Plan Fact Sheet dated November 1999
Groundwater Remediation
New Hanover County Airport Burn Pit
NCO 981 021 157
Wilmington, New Hanover County, NC
Dear Ms. Hudson:
The Proposed Plan Fact Sheet for the New Hanover County Airport Burn Pit
Superfund Site, Groundwater Remediation, located in Wilmington, North Carolina
has been received and reviewed by the North Carolina Superfund Section. The North
Carolina Superfund Section offers the following comment.
1. The issue of metals contamination being properly eliminated from the list of
contaminants of concern (COCs) by low flow sampling of wells in the source area
has not been addressed in this Proposed Plan. It is recommended that the
following language be added to the paragraph under Statement of Basis and
Purpose on the cover sheet of the Proposed Plan Fact Sheet.
Following the second sentence of the paragraph that ends as follows: " ... instead
of extracting the groundwater and treating it through air stripping." (Add here)
Air Sparging technology can now be considered · as the preferred remedy since
metals contamination was determined by field testing of the source area
groundwater to no longer be contaminants of concern (COCs).
The Intermediate ( 60%) Remedial Design Report, for the original record of
decision (ROD) dated September 1992 proposed a remedy change to Air
Sparging. However, since the original ROD included metals (inorganics:
chromium & lead) as COCs Air Sparging could not be used. All the remedies that
were considered in the original ROD addressed metals contamination including
the preferred remedy pump and treat. Therefore, the PRPs request to change the
remedy to Air Sparging was determined to be inappropriate since Air Sparging
does not treat metals contamination.
401 OBERLIN ROAD, SUITE 150, RALEIGH, NC 27605
PHONE 919·733-4996 FAX [phone]
AN EQUAL OPPORTUNITY/ AFFIRMATIVE ACTION EMPLOYER· 50% RECYCLE0/10% POST-CONSUMER PAPER
RD[)
Ms. Hudson
11-18-99
Page 2 of2
•
After conferencing with the PRPs' representatives in the summer of 1996, low flow (low turbidity) sampling of select monitoring wells was completed at the New
Hanover County Airport Bum Pit Site in the Fall of 1996. The PRPs progress report
dated 6 January 1997 states that: "groundwater samples were collected from monitoring wells MWS-002 and MWD-002 using a low flow sampling technique.
The report states that the sampling and analysis results of these wells" ... indicate no
occurrence of RCRA metals above Federal or State standards. These results suggest
that the previous occurrence of RCRA metals was associated with preservative
leaching of trace metals from the high concentrations of solids found in previous
samples." Laboratory analysis test sheets were attached to the progress report.
If you have any questions or comments, please contact me, at [phone],
extension 341.
Sincerely, c~
~'K-~L Randy McElvee
Environmental Engineer
NC Superfund Section
cc: Grover Nicholson, N.C. Superfund Section
• • I.
November 19, 1999
EPA SUPERFUND UPDATE
AMENDED PROPOSED PLAN FACT SHEET
ADDENDUM
SITE GROUNDWATER
RECEIVED
DEC 061998
,,;_·-r:· iFUND SECTION
New Hanover County Airport Burn Pit
Wilmington, New Hanover County, North Carolina
EPA AMENDS INVESTIGATION OF GROUNDWATER, RECOMMENDS AIR
SPARGING TECHNOLOGY AND DELETES METAL CONTAMINANTS AT
THE SITE.
Statement of Basis and Purpose
This decision descnbes a fundamental change to the groundwater restoration approach presented
in the Record of Decision (ROD) oft he New Hanover County Airport Burn Pit (Site). As the
result of information developed since the original ROD was finalized, the United States
Environmental Protection Agency (USEPA) has decided to employ air sparging as the new
Seiecteci Remedy and deieies the m~tais as contaminants oi concerns. Site-specitic
characterization data indicated the aquifer ground-water plumes flowing beneath and
downgradient of the Site pose a realistic threat to human health or the environment. This change
to the original Selected Remedy was chosen in accordance with CERCLA, as amended, and, to
the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan ,
which states that air sparging is generally recommended in special situations where groundwater is
unlikely to be used in the foreseeable future and therefore can be remediated over an extended
period of time.
. ,,.. " . '\ '. •) '. . ., .. . . . . ' ; ,;· 't. • . • •
~~~~,r-:-~~-~-:..;:~
~~ ..
• NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
FILE COPl
October 20, 1999
Ms. Beverly Hudson
North Superfund Remedial Branch
US EPA Region IV
61 Forsyth Street, Eleventh (11) Floor
Atlanta, Georgia 30303
DIVISION OF WASTE MANAGEMENT
RE: Comments on the Record of Decision (ROD) Amendment
Groundwater Remediation
New Hanover County Airport Bum Pit
NCD 981 021 157
Wilmington, New Hanover County, NC
Dear Ms. Hudson:
The Amendment to the Record of Decision (ROD) dated September 1999 for
the New Hanover County Airport Bum Pit Superfund Site, Groundwater
Remediation, located in Wilmington, North Carolina has been received and reviewed
by the North Carolina Superfund Section. The North Carolina Superfund Section
offers the following comments.
General Comments:
As documented in the States Response to Comments letter dated 15 May 1996, on the
Intermediate (60%) Remedial Design Report, the original ROD dated September
1992 includes some metals (inorganics: chromjum & lead) as contaminants of
concern (COCs). All the remedies considered in the original ROD addressed metals
contamination including the preferred remedy pump and treat: Therefore, the PRPs
request to change the remedy to Air Sparging was determined to be inappropriate
since Air Sparging does not treat metals contamination (see the States comment letter
to the 60% RD dated 10 August 1995).
On 10 July 1996, a representative of the NC Superfund Section participated in a
conference call with Rick Garrett, and Mike Mason Design Engineers/Hydrogeologist
with Richard Catlin & Associates the Potentially Responsible Parties' (PRPs)
Remedial Design consultant. The issues of metals contamination in groundwater and
acceptable low flow groundwater sampling techniques and additional plume
delineation at the New Hanover County Airport Bum Pit Site were discussed. A
similar dialogue took place with Ray Church of New Hanover County and Dennis
Burke his technical consultant on May 8, 1996.
401 OBERLIN ROAD, SUITE 150, RALEIGH, NC 27605
PHONE [phone] FAX 919•715-3605
AN EQUAL OPPORTUNITY/ AFFIRMATIVE ACTION EMPLOYER -SO% RECYCLED/10% POST-CONSUMER PAPER
Ms. Hudson
10-20-99
Page 2 of 4
•
Following these conference calls with the PRPs' representatives, low flow (low
turbidity) sampling of select monitoring wells was completed at the New Hanover County Airport Bum Pit Site in the Fall of 1996. The progress report dated 6 January
1997 states that: "groundwater samples were collected from monitoring wells MWS-002 and MWD-002 using a low flow sampling technique. The report states that the
sampling and analysis results of these wells " .. .indicate no occurrence of RCRA metals above Federal or State standards. These results suggest that the previous occurrence ofRCRA metals was associated with preservative leaching of trace metals from the high concentrations of solids found in previous samples."
Metals contamination being removed from the original ROD is a fundamental change
to the basic features of the selected remedy that must be documented by a ROD
Amendment. Therefore, based on the context of the 1992 ROD and the follow-up
low flow sampling noted in the paragraph above, one of the primary purposes of this ROD amendment is to establish that metals contamination should no longer be considered COCs. Using the above references or your own records please document
that metals are being removed from the list ofCOCs as established in the 1992 ROD.
As you can see the primary focus of this ROD amendment is not stringent standards
or even a better remedy (Air Sparging) but the deletion of metals contamination as a
COC at this Site. The State requests that this theme change be made throughout the
document. If you would like to discuss this or other issues of the ROD further please
give me a call.
Specific Comments:
1. The last paragraph on page 2 states that this remedy (air Sparging) requires less than a five-year. review. The State would like to see, at a minimum, 3 to 5 years of monitoring after the Air Sparging process has attained the performance
standards. This monitoring program is a minimum for verifying that the contaminant plume will remain below performance standards after aquifer
equilibration. Details of the monitoring schedule will be determined in the remedial design/ remedial action work plans. At that time we can decide which wells should be sampled under various scenarios. The final sampling event should include a round of sampling from all-primary boundary and plume monitoring
wells.
2. The second sentence of the sixth paragraph on page 5 does not include appropriate details about the original ROD. The following is recommended
language for this sentence or paragraph starting with the second sentence. "The selected ROD remeqy was pump and treat and was chosen because it was the most effective remeqy that could treat all the COCs al the Site including metals.
Ms. Hudson
10-20-99
Page 3 of 4
•
In Table 1 of the September 1992 ROD. (and through out the ROD) the COCs
were determined to include Benzene. Chloroform. 1.2-Dichloroethane.
Ethylbenzene. Chromium and Lead. The selected pump and treat remedy was
estimated at a present worth cost 0($1.93 million."
3. In the second sentence of the last paragraph on page 5 please replace "be" with
"by" EPA's Ecological Science Division ...
4. The last paragraph on page 6 states that the information repository is maintained
" ... at the EPA Docket Room in Atlanta and at the Library." Please state that the
"Library" is the "New Hanover County Public Library" or include other
appropriate details about where and what Library.
5. Page 7 describes the original selected remedy and references Table I as listing
performance standards that (gro'undwater) "would have been" remediated to.
Table I is missing page 2 of the original Table I from the September 1992 ROD
that includes the metals contaminants chromium & lead. The performance
standards documented in the original ROD must be included in Table I of this
ROD Amendment.
6. The use of the word however in the first paragraph on page 10 has no purpose in
the first sentence of a new section. Recommended wording for the first sentence
follows: "From the beginning of negotiations the PRPs raised concern over the
groundwater pump-and-treat remedy selected in the ROD ... " etc. Actually I am
not sure what purpose this paragraph or the following paragraph serves. I would
not raise these issues again in this document. They really have nothing to do with
why the ROD is being amended. The focus of this ROD Amendment is the fact
that metals contamination was eliminated as a COC at the Site.
7. The State requests that the Rationale for Changing the Selected Remedy be re-
evaluated and re-written. The first 4 paragraphs on page IO really have little or no
relevance to this ROD Amendment. The last three paragraphs on page IO and the
first 2 paragraphs on page 11 include historical details about the progress of the
work and has little or no relevance to the rationale for changing the remedy.
Again the primary purpose for this ROD Amendment is the deletion of metals as
COCs and then changing the selected remedy to Air Sparging.
8. The last sentence of the fourth paragraph on page 11 does not read well. The
following changes are recommended. " ... it is believed that operation of the
pump and treat system for a period of 4. 7 years ... " etc.
Ms. Hudson
10-20-99
Page 4 of 4
•
9. The following changes are recommended to the fifth paragraph on page 11. "
contamination reduction stops before reaching remediation levels ( cleanup
standards). Compounding of the contamination problem may result from the
smearing of contaminants that occurs in the aquifer due to high flow rates during
extraction of groundwater. In many cases pump and treat remedies are long term
containment remedies that take many years to reach performance standards.
Hence at some sites, such as this one, the relative costs associated with this type
of traditional remedy are unwarranted or unnecessary.
Therefore, the USEPA and the State has worked with the PRPs and their
contractor-to accept Air Sparging as an alternative remedy which is a more
effective and less costly groundwater remediation alternative.
10. Please make the following changes at the end of the first paragraph on page 12.
"The Air Sparging remedy will address the contaminated groundwater by
volatilizing the low levels benzene contamination from the aquifer. EPA Region
IV has selected Alternative 5 ... " etc.
11. Please remove the word train from " ... treatment train ... " in the last paragraph
on page 14.
12. The State requests that a revised copy of this ROD Amendment be mailed to the
State for further review and comment after all original comments have been
properly addressed and before finalizing the revised document. The State will
make additional comments (as necessary) and provide a concurrence letter to the
revised document. Please provide a new date on the cover page of the revised
document.
If you have any questions or comments, please contact me, at [phone],
extension 341.
Sincerely,
~ ;~_ 1\J\ciQ~
Randy McElveen
Environmental Engineer
NC Superfund Section
cc: Grover Nicholson, N.C. Superfund Section
ENGINEERS and SCIENTISTS
April I 9, 1999
Ms. Beverly Hudson
· Remedial Project Manager
United States Environmental Protection
Agency, Region IV
I 00 Alabama Street, NE
Atlanta, Georgia 30303-3104
• 220 Old Dairy Road • P.O. Box 10279
Wilmington, North Carolina 28405
Telephone: [phone]
Fax: [phone]
Re: New Hanover County Airport Burn Pit Superfund Site
Wilmington, New Hanover County, North Carolina
Docket No. 94-20-C
CATLIN Project No. 94040
Dear /yls. Hudson:
The attached Feasibility Study Amendment Proposed Scope dated April 15, 1999 defines our plan
(or amending the existing Feasibility Study to incorporate air sparging per your request. We
believe that this will give you adequate documentation to prepare the Record of Decision
Amendment.
Please review the proposed workscope and let us know if this meets your needs prior to us
initiating the work. If you have any questions or comments, please call us so that we may
expedite the process.
Sincerely,
AY #7 u /I¼ /Ii
Gary D. McSmith, EIT
Sile Manager
GDM/GRG/kns
Enclosure
cc: Mark M. Davis, EPA ORC, w/cnc.
G. Richard Garrett. P.G.
Project Manager
Catherine Sanders. US Army Corps of Engineers, w/enc.
Don Hooker, US Army Corps of Engineers, w/enc.
Wanda M. Copley, Ne_w Hanover County Attorney, w/cnc.
Lonnie B. Williams, Jr .. Esq.,
Attorney for Cape Fear Community College, w/enc.
Ray .Church. New Hanover County .Director of
Environmental Management. w/enc.
Thomas C. Pollard. Wilmington City Attorney, w/enc.
Randy McElvccn. NCDENR, w/cnc.
North America • Europe
•
NEW HANOVER COUNTY AIRPORT BURN PIT SITE
CATLIN PROJECT NO. 94040
FEASIBILITY STUDY AMENDMENT PROPOSED SCOPE
APRIL 19, 1999
Recommend preparing a Feasibility Study Amendment that presents new data supporting air
sparging as the selected remedy. U.S. EPA Region IV is then willing to prepare a ROD
Amendment using the amended Feasibility Study as the .foundational reference justifying the
change in remedy. The Feasibility Study Amendment will not reiterate any information regarding
other potential alternatives, nor will it introduce any additional alternatives except air sparging.
The existing Feasibility Study is organized into five sec:ions as follnws:
Executive Summary
l .0 Introduction
_ 2.0 Identification, Screening, and Evaluation of Technologies and Process Options
3.0 Evaluation of Remedial Action Alternatives
4.0 Analysis and Summary of Alternatives
Recommended changes to each of the five sections are as follows:
Executive Summary
Write approximately two written pages of .text that updates and summarizes site activities to
date and remedy selection changes resulting from the Feasibility Study Amendment.
Add a description of air sparging in a stand-alone table formatted like existing Table ES-!
for air sparging. The existing Table ES-I will not be reproduced in the Amendment. Only
air sparging information will be presented in the table amendment.
1.0 Introduction
Add excerpts from the existing Air Sparging Pilot Test Treatability Study Report that
summarizes the history and results of the study and report.
Discuss how metals are no longer a concern at the site. Add recent drawings and tables
showing extent of contamination.
2.0 Identification. Screening. and Evaluation of Technologies and Process Options
The purpose of this section is to perform initial technology screening. Air sparging dropped
out in Table 2. l of the original Feasibility Study because of "potential for volatilizing organic
contaminants and• recontaminating clean soils and ineffectiveness in removing inorganic
New Hanover County Burn Pit; 4040amnd.scp
CATLIN Project No. 94040
CATLIN Engineers and Scientists
April I 9, 1999
•
·contaminants." Refute these arguments by reviewing data from history of air sparging to
address vadose .zone soils concerns and stating that chemicals of concern are 'voes. Metals
are no longer a concern due to low flow sampling ,techniques. We are not .going to reevaluate
other alternatives.
3.0 Evaluation of Remedial Action Alternatives
Add information for Alternative 6, Air Sparging. Write text Section 3.7 Alternative 6, Air
Sparging. Use existing reports to cut and paste as much as possible.
4.0 Analvsis and Summary o'r Alternatives
Prepare an addendum to Tables 4-1, 4-2, 4-6, 4-7, 4-8, and 4-9 that includes information on
air sparging only.
New Hanover County Burn Pit; 4U40amnd.scp
CATLIN Project No. 94040
· CATLIN Engineers and Scientists
April 19, 1999
MICHAEL F. EASLEY
/\TIOBNEY GENEH/\1.
State of North Carolina
Department of Justice
P. 0. BOX629
RALEIGH
27602·0629
MEMORANDUM
TO:
FROM:
DATE:
RE:
Rob Gelblum
Phil Telfer ~
October 6, 1993
New Hanover County Burn Pit Site
REPLY TO: Philip A. Telfer
Environmental Division
[phone]
[phone]
·· Thi~ is a follow-up to the meeting regarding 'the · New Hanover County
Burn Pit site. During the conference call, EPA did raise the issue of whether
the revisions to 2L would eliminate the Rules as ARAR's. I related Bill Meyer's
idea of how the Rules. would be applied to Superfund sites in the· future: if a
site qualified for one of the new subsections of 2L .0106, the State would pro-
pose that subsection as the ARAH for a ROD. This explanation seemed to
move the assembled multitude in Atlanta from grave duubts regarding the Rules'
status as an ARAR to "its a difficult ·question." ·
Based on EPA's comments, it would behoove us to be prepared on other
sites to. __ address two issues: (1) consistency of application between Sup.erfund and
non-Superfund sites (EPA. was using consistency in general, not limited to this
comparison); and (2) the guidance's provision that variances and exceptions can be
ARAR's. Please . share your conclusions with the Superfund Branch to make sure
positions taken on the Burn Pit will not endanger ARAR status for 2L i_n the
future.
Call me if we need to discuss.
PAT/vph
cc: Bill Meyer
Richard Whisnant
ep:robmemo.pt
An Equal Opportunity/ Affirmative Action Employer
• • UNITED ST ATES ENVIRON ME NT AL PROTECTION AGENCY
REGION IV
345 COURTLAND STREET. N.E.
SEP 2 5 1992
4WD-NCRS
Mr. Michael A. Kelly
Deputy Director
ATLANTA. GEORGIA 30365
North Carolina Department of Environment, Health, and Natural Resources
Division of Solid Waste Management P.O. Box 276B7
Raleigh, North Carolina 27611-76B7
RE: State's Concurrence on the New Hanover County Airport Burn Pit Superfund Site Record of Decision
Dear Mr. Kelly:
RECEIVED
SUPERFUN'.l SECTION
EPA-Region IV appreciates the State's concurrence on the Record of Decision (ROD) for the New Hanover County Airport Burn Pit Superfund Site located in Wilmington, North Carolina. For the record, EPA would like to respond to your September 24, 1992 concurrence letter. Your letter, along with this response, will be included in Appendix A of the ROD. These letters should stand as official documentation that EPA-Region IV and North Carolina Department of Environment, Health, and Natural Resources have agreed on the preferred alternatives at this point in time.
For your information, the Agency has incorporated the States' a groundwater standard of 1. O ug/1 for benzene as the performance standard. in the ROD. And the Agency recognizes that the State may in the future put in place, pursuant to State' law (General Statute 13OA-310.B), a deed recordation/restriction to document the presence of residual contamination which may limit the future use of the property.
Please contact me at ( 404) 3457-7791 if you have any questions or comments regarding this matter.
Sincerely yours,
~k' 6owJL.---·_
Jon K. Bornholm
Remedial Project Manager
cc: Curt Fehn, EPA
John Walch, NCDEHNR
Printed on Recycled Paper
•
: Ip Jo 1992 s
State of North Carolina \ ,f
Department of Environment, Health and Natural R":\!)urces "
Division of Environmental Management ~~ , .,.,I!
512 North Salisbury Street• Raleigh, North Carolina 2760 91,ow•~•
James G. Manin, Governor
William W. Cobey, Jr., Secretary
A. Preston Howard, Jr., P.E.
Acting Director
Regional Offices
Asheville
704/251-6208
Fayetteville
919/486-1541
Mooresville
704/663-1699
Raleigh
919/571-4700
Washington
919/946-6481
Wilmington
919/395-3900
Winston-Salem
919/896-7007
September 24, 1992
M E M O R A N D U M
TO: Bill Meyer, Director
Division of Solid Waste Management
FROM: ~A. Preston Howard, Jr. ~(~
SUBJECT: lNew-Hano:v:er_County_Airpor.t_Burn_~ft"7
Wilmington, New Hanover County
Review of Draft IRe_c_ord_of-Decisiol).
Project #92-44
As requested, the Division of Environmental Management has
reviewed the subject document. The comments from our Water
Quality, Air Quality and Groundwater Section are provided
below:
Air Quality
The selected remedy includes air stripping. The air
stripper must be registered with the NC DEHNR. The
following information must be submitted to DEM -AQ
Section prior to operating the air stripper;
name of company operating source
principal company contract
location of source (address)
site diagram which shows streams, roads, homes,
buildings
description of process
total air flow -stack height -fuels used
total weight and kind of air pollution released
calculations used to determine daily emissions
acceptance of requirement to notify DEM in event
emissions increase (above stated values)
length of time remediation activities will last
An air permit is not required for the system described
Pollution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer
' . • •
since there is no control device.
Materials presented in the Draft Record of Decision are
nearly sufficient to meet registration requirements, however,
the Air Quality Section has not retained this information or
registered the system.
DEM requests this information be sent to the Regional
Office. Registration letters may be brief. Questions
concerning registration may be directed to John Anderson at
[phone].
Water Quality
Will the city of Wilmington accept this waste stream?
It would appear that without adequate pretreatment
(oil/water separator, filtration, air stripping, and
activated carbon) that this activity may require a
modification of the City"s NPDES Permit.
Will the metals identified in the waste stream have
any significant adverse impact on the City"s
wastewater treatment facility and/or sludge disposal
activities?
Groundwater Section
We will recommend assessment of the semi-confined aquifer.
Also, we recommend that groundwater remediation occur until
state 2L standards are achieved for all the contaminants found
in groundwater at the site.
The remediation alternative selected, groundwater
extraction and physical treatment (air stripping) with effluent
discharge to the local POTW, is excellent. This eliminates the
possibility of the effluent contaminating groundwater resources
through land application processes.
Thank you for the opportunity to review the subject
document. Should you have any questions or wish additional
discussion on this matter, please contact Mr. Rick Shiver at
[phone].
APH/sbp/NEWHANOV.SWM
cc: Alan Klimek
Steve Tedder
Nargis Toma
Rick Shiver
Central Files
Groundwater Files
• •
State .of North Carolina
Department of Environment, Health, and Natural Resources
Division of Solid Waste Management
James G. Martin, Governor
William W. Cobey, Jr., Secretary
Mr. Jon K. Bornholm
Remedial Project Manager
24 September 1992
US Environme_ntal Protection Agency
Region IV
345 Courtland Street, NE
Atlanta·, GA 30365
RE: Concurrence . on Record of Decision
New Hanover County Airport Burn Pit NPL Site
Wilmington, New Hanover County, NC
Dear Mr. Bornholm:
William L. Meyer
Director
We have received and reviewed your responses . to comments made on the Draft
Record of Decision. The Division of Solid Waste Management concurs with the selected
remedial alternative with the following exception. The remediation goal for benzene at the
Site should be 1 ug/1. Benzene can be accurately detected at or below this level by US EPA
Method 602. Any deviation from this remediaton goal will require a waiver from the North
Carolina Division of Environmental Management. Areas where state water quality
standards are not achieved will require deed recordation.
If there are any questions, please call me at (9 I 9) 733-4996.
cc: Curt Fehn, US EPA
Perry Nelson, NC DEM
Sincerely,
-
ichael A. lv----'1-
Depu
P.O. Box 27687, Raleigh, North Carolina 27611-7687 Telephone [phone]
An Equal Opportunity Affirmative Action Employ:r
•
:, SEP J o ,992 ~
State of North Carolina 1, ,,
Department of Environment, Health and Natural ~ urces ~
Division of Environmental Management q,.rot \ -,.<I:.
512 North Salisbury Street• Raleigh, North Carolina 2760 •ow~\,
James G. Manin, Governor
William W. Cobey, Jr., Secretary
A. Preston Howard, Jr., P.E.
Acting Director
Regional Offices
Asheville
704/251-6208
f'aycttcvillc
919/486-1541
Mooresville
7(\4/663-1699
Raleigh
9l'!/571-4700
Washington
9 I 9/946-(,181
\Vilmington
919/395-3900
Winston•Salcm
919/896-7()()7
September 24, 1992
M E M O R A N D U M
TO: Bill Meyer, Director
Division of Solid Waste Management
FROM: ~A. Preston Howard, Jr. ~[c'.~
SUBJECT: New Hanover County Airport Burn Pit
Wilmington, New Hanover County
Review of Draft Record of Decision
Project #92-44
As requested, the Division of Environmental Management has
reviewed the subject document. The comments from our Water
Quality, Air Quality and Groundwater Section are provided
below:
Air Quality
The selected remedy includes air stripping. The air
stripper must be registered with the NC DEHNR. The
following information must be submitted to DEM -AQ
Section prior to operating the air stripper;
name of company operating source
principal company contract
location of source (address)
site diagram which shows streams, roads, homes,
buildings
description of process
total air flow -stack height -fuels used
total weight and kind of air pollution released
calculations used to determine daily emissions
acceptance of requirement to notify DEM in event
emissions increase (above stated values)
length of time remediation activities will last
An air permit is not required for the system described
l'o//ution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Pn11:1l nnf"'l(lrl11ni1v Affirm'lriv" Arlinn ~mnlrwf'.r
• •
since there is no control device.
Materials presented in the Draft Record of Decision are
nearly sufficient to meet registration requirements, however,
the Air Quality Section has not retained this information or
registered the system.
DEM requests this information be sent to the Regional
Office. Registration letters may be brief. Questions
concerning registration may be directed to John Anderson at
[phone].
Water Quality
Will the city of Wilmington accept this waste stream?
It would appear that without adequate pretreatment
(oil/~ater separator, filtration, air stripping, and
activated carbon) that this activity may require a
modification of the City's NPDES Permit.
Will the metals identified in the waste stream have
any significant adverse impact on the City's
wastewater treatment facility and/or sludge disposal
activities?
Groundwater Section
We will recommend assessment of the semi-confined aquifer.
Also, we recommend that groundwater remediation occur until
state 2L standards are achieved for all .the contaminants found
in groundwater at the site.
The remediation alternative selected, groundwater
extractio~ and physical treatment (air stripping) with effluent
discharge to the local POTW, is excellent. This eliminates the
possibility of the effluent contaminating groundwater resources
through land application processes.
Thank you for the opportunity to review the subject
document. Should you have any questions or wish additional
discussion on this matter, please contact Mr. Rick Shiver at
[phone].
APH/sbp/NEWHANOV.SWM
cc: Alan Klimek
Steve Tedder
Nargis Toma
Rick Shiver
Central Files
Groundwater Files
• • UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IV
345 COURTLAND STREET. N.E.
ATLANTA. GEORGIA 30365 RECEIVtD
SEP O 9 199l
SEP 8 1992 SUPERRIND SECTION
I
4WD-NCRS
OVERNIGHT EXPRESS MAIL--RETURN RECEIPT REQUESTED
I
Mr. John Walch
North Carolina Department of Environment,
1Health, & Natural Resources
Division of Solid Waste/Superfund Section
401 Oberlin Road ·
Suite 150
Raleigh, North Carolina 27605
RE: Review Revised Draft Record of Decision for the
New Hanover County Airport Burn Pit Superfund Site
I .
' i Dear Mr. Walch:
Enclosed for the State's review are copies of the revised
Feasibility Study and Record of Decision (ROD) for the New Hanover
County Airport Burn Pit Superfund Site. I have also enclosed a
copy of your August 28, 1992 comments.with hand written notes as to
how the Agency responded to each of the State's comments on the
draft ROD. I trust the responses are adequate and that upon your
receipt of comments from NCDEM, NCDEHNR will be able to transmit to
the Agency a letter of concurrence.
If you have any questions, please fell free to call me at
[phone].
I Sincerely yours,
J:~~==-Remedial Project Manger
enclosures
cc: Mike Kelly, NCDEHNR (w/o encl)
Printed on Recycled Paper
• • ~EC\E~~tOJ
SEP O 9 1992
SUPERflJND SECTION
State of North Carolina
Department of Environment, Health, and Natural Resources
Division of Solid Waste Management
James G. Martin, Governor
William W. Cobey, Jr., Secretary
Mr. Jon K. Bornholm
Remedial Project Manager
US Environmental Protection Agency
Region IV
345 Courtland Street, NE
Atlanta, GA 30365
28 August 1992
RE: Comments Concerning Draft Record of Decision
New Hanover County Airport Bum Pit NPL Site
Wilmington, New Hanover County, NC
Dear Mr. Bornholm:
William L. Meyer
Director
, We have reviewed the above referenced document and are providing the following
comments. The North Carolina Department of Environment, Health & Natural Resources
Division of Environmental Management may be providing additional comments on the Draft ROD. We will forward these to you as soon as we receive them. A Responsiveness Summary for comments submitted on the Draft Feasibility Study must be reviewed by this office prior to receiving a letter of concurrence for the ROD.
Comments Concerning The Record of Decision:
I.
b..tlitt h>l
'gotn c1Ul
: ~ $(,Lo..-~•~.,_
The one year delay to gather additional data discussed in Section I 1.0 of the Decision
Summary is not stated in the Draft ROD. Should this be included in the ROD? Prior to agreeing that the remedial goals have been achieved, the results of at least two successive sampling efforts at the Site will need to reflect contaminant levels at or below the remedial goals set for the Site.
P. 0. Box 27687, Raleigh, North Carolina 27611-7687 Telephone [phone]
An Equal Opportunity Affirmative Action Employer
• •
Mr. Jon Bomholm
Comments on Draft ROD
28 August 1992
Page 2
Comments Concerning The Decision Summary:
4.
5.
6.
7.
8.
9.
10.
11.
Table of Contents: Many page numbers refere~ced are not correct and should be revised
in the final document. Please note, comments are referenced to the original page
numbers shown on document.
List of Acronym~: "Requirement" should be added to the definition of ARAR.
C{)l"-r <-c..,-kJ-. .
General: The pa~e numbering is incorrect ~egjnning with T<\bl~ 19. See comment
Number 2. ;'t-/1 t"l""'!)Ar.'"t .,.,. 1 QJL. c...orr~
Sections 3.0 & 4.0, Pages 7-8: The date of the Administrative Order on Consent seems
to be in question. Paragraph I, page 7 indicates the Order was issued on June 21 1990,
while paragraph 3, P.age 8 indicates t~e Order was §igned. in May 19?0. Please clapfy.
,4-\~ 't\..-i'R'1s <;;3",...t.l '1 /l'\.4'l "IOC. o) ..-of. ,,s...e.! ,,..J.,( .--.. ~a-"' A-f-'t""c. Ir' Aj .4-loVlll""'-,., -f' ..J'"t4 '2-f.
Section 7.0, Page I{, p;),;__ 4: This paragrap md1cates that the volume of impacted
groundwater at the Site is estimated at 9. 7 million gallons. This quantity is not in
agreement with the quantity calculated (7.18 million gal) in comment 27 of your letter
of 5 August 1992 listing all comments made on the Draft Feasibility Study. Please clarify
and if necessill)', revise the duration and associated cost, of groun(lwate~ treatment.
Zt.v;v .! V.>(..-,. ;) 'I, l M r'· -(M"'('""a ~-M ·~ ~,v:_!_'( '-i yo
Section 7.1.2, Page 16: The total PAH's for sample B-21 are reported_to_be_Q.56 mg/kg.
However, upon reviewing the contaminants listed in the referenced Table 3, 0.643mg/kg
was calculated. Corr e.vk J... ' ____ _,,,
· Section 7.2, Page 24, Para. 3: Chang_euinstall" to "installed".
~ A (er ni . ..,~d_ .
Section 7.2, Page 24, Para. 3: This paragraphs states that a total of 10 (ten),different
VOC's, 7 (seven) different SVOC's and 21 llletals were detected in the groundwater at
the Site. The data presented in, Ta~les 6 and 7 does not supr.ort this. · -ti, ;D _ Q..._\;+r ;~ •¼\.tw..:lr 1,...., ~ "Ull t. '<ft--.~ • .(: ._! 11 •~ ft ;i.,.
Section 7.2, Page 25, Para. I: This paragraph states that the MW-002 well cluster is
located approximately 50 ft downgradient of the former bum pit location. However, the
well cluster is actually southweslof..tm;_former bum pit location. The groundwater flow
direction indicated inQ.ection-'Z.2..para::Gis to the south-southeast. ·
4 L..,~ e,_k,..,._,,_-J-
Section 7.3, Page 36, Para. I: This paragraph states that the regional groundwater flow
direction is generally to the southwest, however Section 7.2, para. I states that
groundwater flow direction is to the south-southeast. The direction of flow should be
consistent throughout the document. ~ cf}l.)K._
f(l~",...l ~·o,vJ\ ttrw :, it» s'
~-r J) .sl'l\~ er~
• •
Mr. Jon Bornholm
Comments on Draft ROD
28 August 1992 _
Page 3
12.
13.
14.
15.
16.
Table 6, Page 32: The May 1991 sample results table was mis-copied.
Table 6, Page 33: The July 1992 sample results table:indicates that methyl butyl.ketone
was detected in MWS-002, this is not reflect~-~,.r~,;;.,.., ~
Section 7.4, Page 36, Para. 1: This paragraph indicates that metals are chemicals of
concern at the Site. However, the last paragraph in Section 7.2 indicates that metals are
not considered to bt:,. a significant Site related contaminant. Please clarify. ,._....,..,.,.. : -\..~+ tf i)~ Sw\-1... '1-2-lw> bA-1"' e,l,u,"!"d..
Table 8, Page 42: This table indicates that chloroform is a chemical of concern,
however, Section 7.2, page 24 states that acetone and chloroform were introduced during
field activities and should not be considered. L,,'o"f i~ s. ~. 7. ,._ c.l...."-8"'.I..
Section 8.0, Page 42: Ch<l11ge "summaries" to "summarizes".
urn c.-kd. 1.~ Table 17, Page 64: Please clarify why t~e NCAC Title 15, Subchapter 2L, Section .0202
1.,+"f •,-, groundwater quality standard for benzene was not included in Table 17. The last ·\:• . .;f sentence in Section 9.1.2 states: "The most stringent state or federal requirements were
~•' ..,.. ,~ ~ included in the table". The NCAC 15 -2L.0202 groundwater standard for benzene is ', ~ i ;~'y 0.001 mg/I which is a lower concentration, thus more stringent, than the MCL, 0.005 W-"v-~, ,,. g/1, referenced in the Table. Where state groundwater standards are achieved, the . <,•;;<-~ uounty will need to implement deed restrictions at the Site through an agreeme!)t signed • •., prior to the ROD. In addition, under the Inactive Hazardous Response Act, N.C.G.S. N~ x Section 130A-310.8, deed recordation is required for those areas where State ~~q, ~ roundwater standards are not achieved. · -,:ea~ ... w:\l 'ti.I,\ 'r,.L d,..e, lt ..., :-I'\.,. Q.ov
18. Section 9.3.3, Page 70: The total cost of this option appears to be low. The estimated
19.
-~rio(j,of operati"on should be increased from 3 (three) years to 4 (four) years. Section
7.0 indicates the volume of contaminated groundwater is estimated at 9.7 million gallons, according to previous estimates 3 pore volumes will be removed during remediation,
therefore the total volume of contaminated groundwater equals 29.1 million gallons (9. 7
mg x 3 volumes). Three 5 gpm pumps are proposed, for a total of 15 gpm (5 gpm x 3
pumps). In one year, 7.884 million gallons will be pumped (15 gpm x 60 min/hr x 24
hr/day x 365 days/year). Therefore, ft will take approximately 4 years of operation to
remediate the Site (29.1 mg I 7.884 mg/year = 3.69 years or approximately 3 years 9
months). After periodic shut downs for maintenance, and any additional shut downs due
to mechanical failure, etc., the system will ope1ate for at least 4 (four) years. , _w_, Cc,.., h -Y\A,,f\l.., \;..w,. "-(r t1..t--~ .L-• u.. r .J,~ 1u, bu--, 1~
Sections 9.3.4 & 9.3.5, Pages 71-72: Do the estimated costs and operating times of these
alternatives need to be adjusted to reflect the larger volume of contaminated water than
was previously estimated in the Draft Feasibility Study? IL..ty h.A.vi ~"\ ~
• •
Mr. Jon Bornholm
Comments on Draft ROD
28 August 1992
Page 4
20.
21.
22.
23.
24.
25.
Tables 20 & 21.1 The columns reflecting costs should· be adjusted for Remedial
Alternatives 3 -S: to reflect the increased volume of contaminated groundwater and the
longer period of bperation. ~/Y,, J c.,u h h..vl ~ .◄cl t1<I .-.~
'"u>rr
Section 10.3.1, Page 78: The State of North Carolina will not concur on the Record of
Decision until all comments on the Draft Feasibility Study, Proposed Plan, Draft Record
of Decision and Decision Summary are adequately addressed. u,,.k,.st.o.l
Section 10.3. , Page 79: Delete the extra "n" from "no". · , 1
:,. \\_ '11. ..,\.... l._ ~ ,.-t, :.-¾ ~ r t,v, ~ d .
Table 22, Page 80: See Comment No. 17 concerning the remediation level for benzene.
A lower remediation level for benzene will also change the risk level associated with
benzene at the Site. Q...\..r. \w e..rwc-H!Syo"~ fA ,,_ C., ... ..,.J IJ-1).
Section 11.4, Page 84: The total present worth cost indicated in the first sentence does
not coincide with the cost shown at the bottom of the chart. Also, the costs presented
in the chart do not add to the totals shown. (A.ic\-Ct.,:~ ~ $,4w.J.
Section 11.4, Page 84: The costs shown in this Section may require revision because of
the larger volume of contaminated groundwater indicated by Section 7.0. See Comment
No. 18. C..,rr ~
26. Section 11.4, Page 85: The cost chart is incomplete. Are costs shown lump sum costs
or per year? Co r c ~Ll
If there are any questions, please call me at [phone].
~lyJ. JlL
John W. Walch
Environmental Engineer
Superfund Section
MEMORANDUM
TO:
FROM:
RE:
• •
31 July 1992
File
John Walch, Environmental Engineer ~i 1
Inactive Hazardous Sites Branch u'-'
Record Of Decision
New Hanover County Airport Burn Pit
Wilmington, New Hanover County
NCO 981021157
Jon Bornholm called today to inform me that in a meeting
earlier today with his superiors {Curt Fehn & Bobby Jordan), an
amended version of Alternative No. 3 is going to be the selected
alternative for the ROD.
The ROD will recommend that Alternative No. 3 be enacted after
a one (1) year delay for monitoring. Mr. Bornholm informed me that
due to the time schedule for contracting and design the actual
implementation of the remedial action would not occur for
approximately one (1) year. Therefore, any remediation of
groundwater at the site would not occur for approximately two (2)
years from the date the ROD is signed. The additional one year
would allow for more monitoring of the site, if this monitoring
reveals that contaminant levels are naturally decreasing, the pump
& treat system would not be used.
MEMORANDUM
TO:
FROM:
RE:
• •
30 July 1992
File
John Walch, Environmental Engineer ~f~J
Inactive Hazardous Sites Branch ~-
Potential Record Of Decision
New Hanover County Airport Burn Pit
Wilmington, New Hanover County
NCD 981021157
I spoke to Jon Bornholm today to express the Superfund
Section's concerns over the potential No Action/Long Term
Monitoring ROD for the site and to ask for the responses to the
Section's comments of 10 June 1992 (hand delivered by Mike Kelly at
the public meeting). Mr. Bornholm did not recall the letter.
I indicated to Mr. Bornholm that there is a good possibility
that if EPA does not remediate the site, NC DEM may become involved
and require the site to be · remediated to NC drinking water
standards. I indicated that the New Hanover County may not be aware
of this and should be informed.
I also told Mr. Bornholm that the benefits of remediating the
site now would probably be much greater than to have long term
monitoring and potential future remediation of the site. After
discussing long term monitoring at the site, I asked Mr. Bornholm
what mechanisms could or would trigger a remedial action at the
site. Mr. Bornholm indicated that he had thought of several
possible triggers for future action: if the property is sold, off-
site migration of contaminants and/or no decrease in contaminant
levels over time.
I asked Mr. Bornholm how the ROD was affected by the cost of
different alternatives. Mr. Bornholm did not directly answer. He
stated that the ROD was risk driven. I told Mr. Bornholm that we
felt that the proposed cost for pump & treat was extremely high and
could be decreased. Mr. Bornholm stated that the contractor had
informed him that the $100,000 pretreatment process proposed was
probably not necessary for the site due to the short duration of
the project and limited time for fouling of the air stripping
packing.
• •
Mr. Bornholm also informed me that benzene levels at the site
had not yet begun to naturally decrease due to biodegradation. The
levels of benzene at the site were:
MWS-2
MWD-2
DATE
4/91
5/91
11/91
7/91
4/91
5/91
11/91
7/91
LEVEL (ppbl
110
31
74
96
110
94
110
88
Mr. Bornholm also informed me that with the elimination of
beryl~ium du_e to the_ higher MCL ( 1 to 4 ppb) t;pe risk leve_~
associated with the site had decreased from 1 x 10 to 3.1 x 10
which is within the US EPA's acceptable range. Therefore, with the
risk being decreased, the driving force behind remediation has been
eliminated and remediation may not be justifiable.
Mr. Bornholm informed me that he would keep me informed of the
ROD's status.