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Operable Unit 2

Background

OU2 is located in the west-central portion of MCAS Cherry Point and covers approximately 104 acres. OU2 is bounded by the STP and OU3 to the north, Roosevelt Boulevard to the east, a residential area to the south, and Slocum Creek to the west. There are three FFA sites grouped within OU2 because of their proximity to the Old Sanitary Landfill (Site 10).

The IAS conducted in 1983 identified Site 10.  Site 46 was identified in the RFA conducted in 1988, and an RRR identified Site 76 in 1995.  An RI for OU2 was conducted in 1994 and 1995, and included borehole geophysical logging; soil, groundwater, surface water, leachate seep, and sediment sample collection; and surface water level monitoring (B&R, 1997a). The RI concluded that groundwater in the surficial aquifer was contaminated with a wide range of organic contaminants (VOCs, SVOCs, and pesticides) and metals. In addition, there were several VOC “hot spot” areas of soil contamination identified. An FS was recommended to evaluate potential remedial actions.

Remedial alternatives for OU2 were evaluated in the FS (B&R, 1997c), presented in the Proposed Remedial Action Plan (PRAP) (B&R, 1996c), and finalized in the ROD for OU2 (TT, 1999b). The selected remedy included natural attenuation of groundwater, soil vapor extraction (SVE) at major soil “hot spots,” institutional controls (ICs), and LTM of groundwater, surface water, and sediment to ensure the effectiveness of natural attenuation. Land Use Controls (LUCs) were established, which restrict site use to industry only, prohibit intrusive activities below the water table, and prohibit groundwater use (CH2M HILL, 2002a).   In 1996, a soil vapor extraction (SVE) pilot study was conducted, and in 1997 a full-scale SVE system to treat soil at four soil “hot spot” areas was installed.  According to the five year review, the SVE remedy in place was operating as designed since March 1998; VOC mass removal continued to increase at significant rates in Hot Spots 1 and 3, while little to no removal has been observed at Hot Spots 2 and 4.  The SVE treatment of the soil hot spots was discontinued in August 2003 because the system was no longer removing a significant mass of contamination and was not performing as a cost-effective remedial approach. Variations to this system, along with other technologies, will be evaluated for future use.  Quarterly and annual reports of system status and routine monitoring have been submitted.

Fish tissue samples were collected from Slocum Creek adjacent to OUs 1, 2, 3, and 4 in 1998 and the results indicated no potential unacceptable risk to human health from fish tissue ingestion (TT, 1999a). In 1999, surface water and sediment samples were collected adjacent to OUs 1, 2, 3, and 4 as part of a SLERA in Slocum Creek (TT, 2001). No consistent patterns of contamination were observed. The results suggested that the presence of high concentrations of numerous trace metals in bottom sediments of Slocum Creek reflect a substantial impact upon the overall environmental quality of the Slocum Creek estuarine system.

Annual LTM of groundwater began in October 2002. A summary of the samples collected at OU2 as part of the ongoing LTM program is included in Table 3-5. Annual LTM will continue until it is confirmed that the constituents detected in groundwater do not exceed the performance standards identified in the ROD (CH2M HILL, 2002b).

Site 10—Old Sanitary Landfill

Site 10, the Old Sanitary Landfill, is approximately 40 acres and is located west of Roosevelt Boulevard, south of the STP (Site 43), and east of Slocum Creek and covers approximately 40 acres. Site 10 is divided by Turkey Gut, a small perennial stream that flows northwest into Slocum Creek. The site consists of a sanitary landfill, former sludge impoundments, and a former drum storage area, which was used to store petroleum products.  The former drum storage area is currently used to store miscellaneous equipment and is fenced and covered with gravel.

Site 10 served as the primary landfill at MCAS Cherry Point beginning in 1955. Before the late-1970s, all landfilling activities were carried out south of Turkey Gut. Subsequently, landfilling operations also occurred north of Turkey Gut. Landfill operations ceased at Site 10 in the early to mid-1980s. Industrial wastes reportedly disposed of in the landfill included POLs, solvents, and sludges. The quantity of wastes are unknown, but are estimated to be thousands of tons. Hazardous liquids and POLs were also spread on the landfill surface and burned, deposited in unlined pits on the south side of Turkey Gut, and buried at the landfill.

Between 1984 and 1987, an IRI was conducted to identify contaminated sites and included the collection of soil, groundwater, surface water, sediment, and leachate seep samples and aquifer testing at Site 10. Contamination, primarily VOCs, was verified in the shallow groundwater, soil, and sediment at Site 10.  For the RFI conducted between 1989 and 1991, soil, groundwater, surface water, and sediment samples were collected, and a soil-gas survey and aquifer testing were conducted at Site 10 based on data gaps identified from previous investigations (NUS, 1991).

The Phase I TDM conducted in 1992 included magnetometer survey, soil sampling, and test pits excavation (Halliburton NUS, 1992). Additional test pits and/or soil borings were recommended to further delineate the horizontal and vertical extent of soil contamination, primarily VOCs and metals, in the area just south of Turkey Gut. During the Phase II TDM, a terrain conductivity survey, additional test pit excavation, and soil sampling were conducted. No further investigation of soils was recommended just south of Turkey Gut based on low concentrations and localized contamination found in soil. Additional soil borings were recommended in the central portion of the landfill to further delineate the horizontal and vertical extent of soil contamination, primarily VOCs and metals (Halliburton NUS, 1994a).

 

Site History—Operable Unit 2, Site 10
Event	Date
POL, solvents, and sludges disposed of at Old Sanitary Landfill	1950s to 1980s
Hydrogeologic and Geotechnical Analysis	1981
IAS	1983
IRI	1988
Groundwater Assessment	1988
Evaluation of Sludge Impoundment Area	1991
RFI	1991
Phase I Technical Direction Memorandum	1992
Phase II Technical Direction Memorandum	1994
Basis of Design Report for Air Sparging System	1997
Air Sparge Work Plan	1997

 

 

Site 46—Polishing Ponds No.1 and No. 2

Site 46 is located to the north of Site 10, and consists of two inactive, unlined ponds. The ponds are approximately 12 ft deep and formerly served as wastewater aeration basins for the STP from 1942 until 1996. The treated wastewater was discharged to Slocum Creek via a National Pollution Discharge Elimination System (NPDES)-permitted outfall.  The STP was upgraded and no longer requires the use of the ponds for aeration. The ponds have been retained for potential storm water management in the future, and concurrence will be obtained from the USEPA and NCDENR prior to use of these inactive ponds. MCAS Cherry Point submitted a Closure Plan for this site to the State of North Carolina in December 1988. EPA Region 4, which formerly had primacy, agreed to waiving the closure requirements, allowing the ponds to be addressed under the NCDENR RCRA authority.

 

Site History—Operable Unit 2, Site 46
Event	Date
Wastewater aeration basins	1942-1996

 

 

Site 76—Vehicle Maintenance Area (Hobby Shop)

Site 76 is a fenced area located south of Site 10, and consists of a garage building and parking lot where personal vehicles are repaired. The area covers approximately 250 ft by 250 ft, and is bounded by a wooded area adjacent to Slocum Creek, a residential area to the east, Site 10 to the north, and a wooded area to the south. Site 76 is the only site at OU2 that is currently active.  Ongoing site activities include general auto maintenance and auto body repair. Based on a review of historical aerial photographs, the Site 76 area was developed between 1958 and 1964.

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Operable Unit 3

Background

OU3 is located in the west-central portion of MCAS Cherry Point and covers approximately 19 acres. OU3 is bounded by Slocum Road to the north, the STP and OU2 to the south, Slocum Creek to the west, and an adjacent wooded area to the east. OU3 consists of two FFA sites that were grouped into one OU because of their proximity and common waste types.

Sites 6 and 7 were identified in the IAS conducted in 1983.  Between 1984 and 1987, an IRI was conducted that included groundwater sampling at Site 6.   In 1991 and 1993, soil, groundwater, surface water, and sediment samples were collected at Sites 6 and 7 as part of the 21-Unit RFI.  During 1992, soil and groundwater samples were collected as part of the 10-Unit TDM. Recommendations included additional soil sampling to evaluate the presence or absence of combustion byproducts such as PAHs; groundwater, surface water, and sediment sampling; and evaluation of the interaction between groundwater, surface water, and sediment and the lime/alum ponds (Halliburton NUS, 1993b).

An RI was conducted from 1994 to 1996, and included the collection of soil, groundwater, surface water, and sediment samples, borehole geophysical logging, and surface water level monitoring. Analytical results for Site 6 indicated that this area has been relatively unaffected by fly ash disposal activities or incineration/burning at Site 7; however, minimal residual material remained onsite.

Remedial alternatives for OU3 were evaluated in the FS (B&R, 1996d), presented in the PRAP (B&R, 1996e), and finalized in the ROD for OU3 (TT, 2000). The selected site-wide remedial action for OU3 is monitored natural attenuation and institutional controls for groundwater, and soil vapor extraction and institutional controls for soil (OHM, 1998b). The LUCAP elements in place at OU3 are listed in Table 3-4.

Fish tissue samples were collected from Slocum Creek adjacent to OUs 1, 2, 3, and 4 in 1998; the results indicated no potential unacceptable risk to human health from fish tissue ingestion (TT, 1999a). In 1999, surface water and sediment samples were collected adjacent to OUs 1, 2, 3, and 4 as part of a SLERA in Slocum Creek (TT, 2001). No consistent patterns of contamination were observed. The results suggested that the presence of high concentrations of numerous trace metals in bottom sediments of Slocum Creek reflect a substantial impact upon the overall environmental quality of the Slocum Creek estuarine system.

Annual LTM of groundwater began in October 2002. A summary of the samples collected at OU3 as part of the ongoing LTM program is included in Table 3-5. Annual LTM will continue until it is confirmed that the constituents detected in groundwater do not exceed the performance standards identified in the ROD (CH2M HILL, 2002c).

Site 6—Fly Ash Ponds

Site 6 formerly consisted of three unlined ponds bounded by Slocum Creek to the west, Luke Rowe’s Gut to the south, and Slocum Creek Road to the north and east. The ponds covered approximately 2.5 acres and were approximately 10 to 15 ft deep.  The ground surface west of the former pond locations slopes steeply to approximately 5 ft above msl, giving way to a flat and heavily vegetated area adjacent to Slocum Creek. There are wetland areas adjacent to Slocum Creek and Luke Rowe’s Gut, and a portion of the site lies within the 100-year floodplain of Slocum Creek.  Fly ash and cinders from the old power plant were disposed of in the ponds from the 1940s until about 1970. The ponds were then reportedly used for the disposal of lime/alum sludge from the potable water treatment plant from December 1980 until the new water treatment plant became operational in mid-1994. It was also reported that up to 5,000 gallons of waste POLs were disposed of in the ponds (Water & Air Research, 1983).  A review of historical aerial photographs indicated that the ponds were not constructed until the late 1950s.  Earlier aerial photographs indicate the presence of a natural pond and/or shallow depressions. The third pond appeared in an aerial photograph from 1978 (B&R, 1996f).

In 1996, as part of the closure of the water treatment plant, the ponds at Site 6 were removed.   This non-ER,N funded effort was accomplished by solidifying and excavating the pond sludge, removing piping and debris, leveling the berms, and revegetating the site.  The site was revegetated with pine seedlings in 1996 by MCAS Cherry Point personnel as part of a “Longleaf Pine Initiative” to return the land to its natural state (OHM, 1998b). The boundaries of the various LUCs in place at OU3 are listed in Table 3-4. Annual LTM began in October 2002 and will continue until it is confirmed that the constituents detected in groundwater do not exceed the performance standards defined in the OU3 ROD.

 

Site History—Operable Unit 3, Site 6
Event	Date
Disposal of fly ash and cinders	1940s to 1970
Solidification and excavation of pond sludge, removal of piping and debris, berm leveling	1996
Revegetation of site	1996

 

 

Site 7—Old Incinerator and Adjacent Area

Site 7 formerly consisted of an incinerator and open burning ground that covered approximately 5 acres. It is bounded by the STP to the south and east, Luke Rowe’s Gut to the north, and Slocum Creek to the west. The former incinerator was reportedly located adjacent to Luke Rowe’s Gut in the eastern part of the site. The open burning area was reportedly south of Luke Rowe’s Gut near its confluence with Slocum Creek.

From the 1940s until approximately 1955, waste POLs, NADEP wastes, and other wastes (including municipal refuse) were burned in the incinerator or on the adjacent open burning grounds. Fly ash disposal and open burning are suspected in the western portion of Site 7. The fly ash is believed to have originated from the incinerator, and was reportedly mixed with other wastes. Aerial photographs indicate that the incinerator was removed between 1981 and 1984.

As part of the selected remedy at Site 7, a fence and warning signs were installed, and  soil samples were collected (OHM, 1998b). In 2000, OHM installed an air sparge system for enhanced bioremediation of a localized area of soil contamination.  In 2000, OHM installed an air sparge system for enhanced bioremediation of a localized area of soil contamination. According to the 2002 5-year review, the AS system at Site 7 was in operation 90 percent of the time and was generally functioning as designed. Based on the February 2001 confirmatory soil sampling results, it was noted that the extent of benzene contamination in soil at Site 7 extends beyond the radius of influence of the current AS system to the southwest and northeast (OHM, 2000).   As a result, additional AS points were installed to address the extended area
of contamination. Based on soil and groundwater monitoring results indicating that the air sparge system had effectively remediated the soil hot spot, the air sparge system was shut down in mid-2003 (CH2M HILL, 2003c). The LTM results will continue to be evaluated to
ensure that groundwater concentrations do not rebound since the air sparging was discontinued.

Operable Unit 4: Site 4 – Borrow Pit/ Landfill

Background

OU4 consists of one FFA site, Site 4, and is located in the northwest-central portion of MCAS Cherry Point and covers approximately 130 acres.  Site 4 is a Borrow PitLandfill North of Runway 14, and is bounded by Mill Creek to the south and west, Rifle Range Access Road to the north, and Duffy Road to the east.

Site 4 consists of several borrow pits that were used for waste disposal, as well as a fenced and lined drum storage area that is located in the north-central portion of the site.   Site 4 was identified in the IAS and RFA, which indicated that the borrow pits were initially excavated in the 1940s. The borrow pits had been excavated to a depth below the water table, and a drain was reportedly cut to Slocum Creek. The disposal of demolition and asbestos wastes began in the 1950s. Other wastes, including wastes from NADEP, may have also been disposed of at Site 4; however, no records were maintained on the types or amounts of wastes. The date that disposal activities ceased at the site is not known (Water & Air Research, 1983). The majority of historical activities at Site 4 took place in the western portion of the site, where the borrow pits used for waste disposal were located. The area was permitted in 1997 as an active land clearing and inert debris landfill, and is currently used for recycling of unpainted/untreated wood, yard waste, and inert construction debris. The drum storage area, located in the northeastern corner of OU4, was visible in the 1988 aerial photograph. The area is now used for the storage of new material for NADEP.

Sampling was  conducted between 1984 and 1987 as part of an IRI.  During the 21 Unit RFI, VOCs were found in groundwater.  A 10-Unit TDM was conducted in 1992. Elevated lead concentrations were found during the RI in Mill Creek sediments in the eastern part of Site 4. Subsequent investigation revealed that the lead concentrations increased upstream from OU4, and were greatest near an inactive skeet and trap range located to the northeast. It was concluded that the lead in Mill Creek sediments did not originate from site activities at OU4, but from the skeet and trap range. Because the lead originated from military
munitions at an operational military range, it was determined that the lead was not a RCRA
solid waste or the result of a release regulated under CERCLA. Therefore, the EPA and NCDENR agreed to remove the lead from consideration as a contaminant of concern in OU4 remedy selection process.

Fish tissue samples were collected from Slocum Creek adjacent to OUs 1, 2, 3, and 4 in 1998 and the results indicated no potential unacceptable risk to human health from fish tissue ingestion (TT, 1999a). In 1999, surface water and sediment samples were collected adjacent to OUs 1, 2, 3, and 4 as part of a SLERA in Slocum Creek (TT, 2001). No consistent patterns of contamination were observed. The results suggested that the presence of high concentrations of numerous trace metals in bottom sediments of Slocum Creek reflect a substantial impact upon the overall environmental quality of the Slocum Creek estuarine system.

The Navy and MCAS Cherry Point initiated interim groundwater monitoring in October 2003 to monitor VOC and SVOC concentrations that were found to exceed State groundwater quality standards during the RI.  VGM has been conducted on a semi-annual basis, and will continue as LTM in 2006. 

The  Final Focused FS was submitted in May 2004.  The OU4 PRAP was finalized in April 2005, followed by the final  OU4 ROD, which was signed in September 2005, and identified two COCs,  1,1,2,2-tetrachloroethane and benzene (CH2M HILL, 2006a).  The Selected Remedy includes monitored natural attenuation (MNA) and LUCs for groundwater.  The LUCs will limit exposure to groundwater and prohibit the use of groundwater, except for monitoring.  The Remedial Design was finalized in April 2006. 

Site History—Operable Unit 4, Site 4
Event	Date
Disposal of demolition and asbestos wastes	1950s, 1982 to mid-1990s
Permitted landfill, used for recycling of untreated wood, yard waste and inert construction waste	1997 to present
IAS	1983
RFA	1988
IRI	1988
21 Unit RCRA Facilities Investigation	1993
10 Unit Technical Direction Memorandum	1993
Slocum Creel Fish Ingestion Report	1999
RI/FS Work Plan	1999
Slocum Creek SLERA	2001
RI	2002
FS	2004
PRAP	2005
Draft ROD	2005

 

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Operable Unit 5

Background

OU5 is located in the northeastern portion of MCAS Cherry Point. OU5 consists of two FFA sites, 1 and 2, that were grouped into one operable unit because of their proximity, history, and common waste types. Site 19 (Borrow Pit/Landfill North of Runway 32) was formerly part of OU5, but was transferred to OU13 because the site is closer to the other OU13 sites.

Sites 1 and 2 were identified in the IAS and RFA.  Between 1985 and 1987, groundwater samples were collected at Site 1 as part of an IRI to identify contaminated sites. The IRI concluded that groundwater had not been affected by historical waste practices at Sites 1 and 2, and that no further investigation was recommended (NUS, 1988).  A 21 Unit RFI was conducted in 1991 that included groundwater sampling. No releases to groundwater were confirmed; however, seepage was observed and as a result, it was not possible to conclude that there had been not been any releases from the borrow pits. Therefore, additional groundwater monitoring and sampling of surface water and sediment surrounding the sites was recommended (Halliburton NUS, 1993c).

During the OU5 RI investigation, soil, groundwater, surface water, and sediment samples were collected. The RI results did not indicate any significant risks to human health or the environment; however, VOC concentrations slightly exceeded State groundwater standards in several monitoring wells. The RI was finalized in August 2005.

The Navy and MCAS Cherry Point initiated interim groundwater monitoring in October 2003 to monitor VOC concentrations that were found to exceed State groundwater quality standards during the RI field investigation. The 2005 VGM Report for OU5 was submitted in May 2006. VGM is
conducted on a semi-annual basis, and will continue as LTM in 2007.  The final RI was submitted in August 2005.  The Focused FS was finalized in October 2005.  The final OU5 PRAP was submitted in November 2005.  The OU% ROD was finalized in May 2006.  It has been determined that No Further Action (NFA) is necessary at Site 1; therefore the ROD addresses remedial action only at Site 2. Three COCs were identified at OU5: trichloroethene, vinyl chloride, and benzene (CH2M HILL, 2006b). The Selected Remedy for Site 2 includes MNA for groundwater and LUCs that will limit exposure to and prohibit the use of surficial groundwater, except for monitoring. Upon signing the ROD, the Remedial Design (RD) will be completed and will outline the implementation of MNA and LUCs at Site 2. The RD is expected to be completed by fall 2006.

 

Site History—Operable Unit 5
Event	Date
IAS	1983
RFA	1988
IRI	1988
21 Unit RCRA Facilities Investigation	1993
Work Plan	2002

 

 

Site 1—Borrow Pit/Landfill

Site 1 is located west of an access road in the northeastern portion of MCAS Cherry Point. It is a former borrow pit area that was later used for waste disposal. The total disturbed area of Site 1 was estimated to be approximately 4 acres. The northern boundary of Site 1 is approximately 100 ft south of Reed’s Gut, and the other boundaries include an unnamed tributary to the west, a line 200 ft north of an unpaved road to the south, and the unpaved access road to the east.

The area was originally used as a borrow pit area, but was later used as a disposal site. Site use reportedly began in the mid- to late-1950s, and continued for an unknown period of time. No records were kept detailing the quantities or types of wastes that were disposed of at the site. Some chemical waste, crushed 55-gallon drums, and construction and demolition debris were reported to have been disposed of at the site, but only small amounts of rubble and trash were seen onsite during the IAS (Water & Air Research, 1983).

Site History—Operable Unit 5, Site 1
Event	Date
Former borrow pit and disposal area	Late 1950s to unknown

 

Site 2—Borrow Pit/Landfill

Site 2 is located east of an access road in the northeastern portion of MCAS Cherry Point, directly opposite Site 1. Like Site 1, it is a former borrow pit area that was later used for waste disposal. The total disturbed area of Site 2 was estimated to be approximately 6 acres. Site 2 is bounded on the east and northeast by an unnamed tributary to Reed’s Gut, an unpaved road to the south and southwest, and an unpaved access road to the west.

The area was originally used as a borrow pit area, but was later used as a disposal site. Site use reportedly began in the mid- to late-1950s, and continued for an unknown period of time. No records were kept detailing the quantities or types of wastes that were disposed of at the site. Some chemical waste, crushed 55-gallon drums, and construction and demolition debris were reported to have been disposed of at the site, but only small amounts of rubble and trash were seen onsite during the IAS (Water & Air Research, 1983).

Site History—Operable Unit 5, Site 2
Event	Date
Former borrow pit and disposal area	Late 1950s to unknown

 

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Operable Unit 6: Site 12 – Crash Crew Training Area

Background

OU6 includes one FFA site, Site 12, the Crash Crew Training Area, and consists of the eastern portion of Runway 28, an east-west trending runway along the eastern edge of MCAS Cherry Point. Initially a second site, Site 35, was included in OU6 due to its proximity to Site 12.  However, Site 35 is listed as a RCRA SWMU and therefore was remediated under the provisions of RCRA. Site 12 is located along the south-central portion of Runway 28. The runway is bordered by grassy areas to the north, south, and east, with dense woods beyond the grass. Hancock Creek is located approximately 700 ft east of the eastern end of Runway 28.

The Crash Crew Burn Pit is a circular concrete pad currently used to burn waste JP‑5 to train crash crews to extinguish fires. The concrete burn pit was reportedly constructed in 1985, and is approximately 100 ft in diameter with a 5‑in.-high curb around the circumference (Halliburton NUS, 1993c). The burn pit itself is drained through subsurface piping to a nearby oil–water separator, as is a circular trench drain that rings the outside of the burn pit to capture fire water not contained within the burn pit. After training exercises or a heavy rainfall, facilities maintenance personnel pump all liquids from the oil–water separator and transport them to the IWTP.

Site 12 was identified in the IAS and RFA, which indicated that Site 12 had been used for crash crew training activities since the mid-1960s. According to the IAS, waste POLs and waste burnable (i.e., likely non-chlorinated) solvents were formerly burned in one of two circular bermed areas on Runway 28, but that only contaminated fuel was burned at the time the report was written. The IAS also indicated that spills and leaks from the burn pits were evident at the time of the report, and that stained and oily soil was present in the drainage swale south of Runway 28. Between 1985 and 1990, effluent from the oil–water separator was discharged through a NPDES-permitted outfall to the nearby drainage swale (Halliburton NUS, 1993c). Around 1990, the effluent pipe of the separator was welded shut.

 

Sampling was conducted during a 21 Unit RFI in 1991. Total petroleum hydrocarbon (TPH) contamination was detected in the soil and sediment samples, and additional sampling of all media was recommended (Halliburton NUS, 1993c). Additional samples were collected in 1993 as part of the 10 Unit TDM. TPH contamination was found to be limited in area and depth; however, further investigation of inorganic constituents in soil and groundwater was recommended at Site 12 (Halliburton NUS, 1993b).

During a 1999 site visit conducted by CH2M HILL, some clarification was obtained regarding the nature of the burn pits that pre-dated the current concrete burn pit constructed in 1985. According to interviewed crash crew personnel, the former burn pits were constructed of dirt placed on top of the asphalt runway surface and shaped into circular berms. The crash crew personnel recalled the existence of two dirt burn pits of this type, and indicated that fuels (including gas and diesel) and magnesium aircraft parts were formerly burned in the pits. A review of historic aerial photographs revealed five separate locations where earthen burn pits had once been located since the early 1960s, with either two or three of the burn pits being present at any one time.

 

The Final RI conducted for OU6 concluded that, based on the limited number of constituents that pose potential human health risk only within an unrealistic exposure pathway, an FS did not appear to be warranted for OU6, and NFA was recommended (CH2M HILL, 2005b). However, regulator concerns regarding the extent of sampling beneath historic burn pit locations were expressed, and a Supplemental Site Investigation (SSI) was initiated in October 2003. The investigation included additional soil and groundwater sampling beneath the former burn pit locations. The final SSI was submitted in May 2005.

The Final RI was submitted in August 2005 and concluded that an FS addressing all exceedances of NC standards was not warranted at OU6. No definitive connection was drawn between Site 12 activities and the constituents identified during the RI, except at Burn Pit E. Based on infrequent detections of constituents exceeding NC standards, minimal extent of groundwater contamination, and lack of human health or ecological risk for realistic exposure pathways, it was recommended that an FFS be prepared for Site 12, addressing only the delineated areas of arsenic, benzene, naphthalene and 2-methylnaphthalene in subsurface soil and groundwater at Burn Pit E. The final FFS was submitted in January 2006.

The PRAP for OU6 was submitted for public review and commenting in May 2006. The Remedial Alternative selected in the PRAP is the excavation and offsite disposal of contaminated soil, along with MNA and LUCs for groundwater. A ROD is currently in draft format and is anticipated to be signed by September 2006. The RD is expected to be completed by fall 2006.

The Navy and MCAS Cherry Point initiated VGM in May 2005 to monitor VOC concentrations found to exceed State groundwater quality standards identified in the FS. The 2005 VGM Report for OU6 was submitted in June 2006. VGM is conducted on a semi-annual basis, and will continue as LTM in 2007 after the ROD is signed and the RD is complete.

Site History—Operable Unit 6
Event	Date
Crash Crew Training activities—burning of waste POLs, solvents and contaminated fuels	mid-1960s to unknown
IAS	1983
RFA	1988
21 Unit RCRA Facilities Investigation	1993
10 Unit Technical Direction Memorandum	1993
Work Plan	1999
Supplemental Investigation Plan	2003
SSI	2005
Draft Final RI	2005
Draft Focused FS	2005

 

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Operable Unit 13

Background

OU13 is located in the southeastern portion of MCAS Cherry Point near Runway 32, and covers approximately 61 acres. Several sites were grouped within OU13 because of their proximity to each other. There are two FFA sites (Sites 19 and 21) within the boundaries of OU13. OU13 also includes releases to groundwater from Site 44B, which was a former sludge application area. OU13 is not currently used for any active purpose other than providing a buffer of cleared land adjacent to Runway 32.

Sites 19 and 21 were identified in the IAS and RFA, and Site 44B was identified in the 21-Unit RFI. Between 1985 and 1987, groundwater samples were collected at Sites 19 and 21 as part of an IRI to identify contaminated sites. In November 1991, additional groundwater samples were collected at OU13 as part of the 21 Unit RFI to support a Corrective Measures Study and to verify releases from various sites. During the RI field activities for OU13 conducted in 1994 and 1999, soil, groundwater, surface water, sediment, and fish tissue samples were collected. An FS was recommended to evaluate remedial alternatives associated with potential unacceptable risks to human health based on concentrations of VOCs, pesticides, and/or inorganic constituents that exceeded screening criteria in groundwater and surface water (TT, 2002b).  

The Navy and MCAS Cherry Point initiated VGM in October 2003 to monitor VOC concentrations that were found to exceed state groundwater quality standards during the RI. VGM has been conducted on a semi-annual basis, and will continue as LTM in 2006. The 2005 OU13 VGM Report was submitted in July 2006. 

The Focused FS was submitted in July 2004. The OU13 PRAP was finalized in April 2005, followed by the final OU13 ROD, which was signed in September 2005. The COCs identified for OU13 include 1,1-dichloroethene, methylene chloride, vinyl chloride, and bis(2-ethylhexyl)phthalate (CH2M HILL, 2005c).  The selected remedy includes MNA for groundwater and LUCs, which will limit exposure to groundwater and will prohibit the use of groundwater except for monitoring. The Remedial Design was finalized in April 2006.

Site History—Operable Unit 13
Event	Site	Date
IAS	19, 21	1983
RFA	19, 21	1988
IRI	19, 21	1988
21 Unit RCRA Facilities Investigation	OU13	1993
RI/FS Work Plan	OU13	1999
RI	OU13	2002
FFS	OU13	2004
PRAP	OU13	2005
ROD	OU13	2005

 

 

Site 19—Borrow Pit/Landfill (North of Runway 32)

Site 19 consists of an area of approximately 16 acres that includes several former borrow pits that were reportedly used for waste disposal. Site 19 is located on the northern side of Runway 32, with Hancock Creek and the tributary Shop Branch to the north and east. There are wetland areas adjacent to Hancock Creek and Shop Branch. 

Parts of Site 19 were first disturbed in 1949 and used through the early 1960s. Fly ash from the steam plant, wastes from NADEP, and asbestos-lined piping may have been disposed of in the borrow pits (Water & Air Research, 1983). No records were kept detailing quantities or specific types of wastes.

 

Site History—Operable Unit 13, Site 19
Event	Date
Several borrow pits used for waste disposal (fly ash from steam plant, wastes from NADEP, asbestos-lined piping)	1949 to early 1960s

 

 

Site 21—Borrow Pit/Landfill (South of Runway 32)

Site 21 consists of an area of approximately 36 acres that includes several borrow pits that were reportedly used for waste disposal. Site 21 is located south of Runway 32, and Shop Branch runs through Site 21 before crossing under the runway.  Parts of the area were first disturbed in 1949 and used through the early 1960s. Fly ash from the steam plant, wastes from NADEP, and asbestos-lined piping may have been disposed of in the borrow pits (Water & Air Research, 1983). No records were kept detailing quantities or specific types of wastes.

 

Site History—Operable Unit 13, Site 21
Event	Date
Several borrow pits used for waste disposal (fly ash from steam plant, wastes from NADEP, asbestos-lined piping)	1949 to early 1960s
10 Unit Technical Direction Memorandum	1993

 

 

Site 44B—Former Sludge Application Area

Site 44B consists of a relatively flat 11-acre area adjacent to Site 21 where sludge from the STP was applied. The area was reportedly a landfill in the 1950s and 1960s, and the waste reportedly included asbestos pipe. Between September and November 1987, liquid sludge from the STP digesters was reportedly land-applied at Site 44B. The sludge may have contained organic compounds and other constituents that were not digested during the sewage treatment process.

 

Site History—Operable Unit 13, Site 44B
Event	Date
Sludge and asbestos pipes disposed of in landfill	1950s and 1960s

 

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Operable Unit 14: Site 90 - Building 130 VOC-Contaminated Groundwater

Background

Site 90 is a plume of groundwater contaminated with chlorinated VOCs that was first identified near Building 130, which is used as a hangar. Prior to the RI currently underway, there have been no investigations or remedial activities specific to Site 90; however, numerous groundwater samples have been collected as part of investigations at the Building 130 abandoned fuel pipeline area. This abandoned aviation fuel pipeline in the area is being addressed under the MCAS Cherry Point UST program.

In July 1994, soil and groundwater samples were collected in the Site 90 area to support a Base Realignment and Closure (BRAC) project. The purpose of the investigation was to identify contamination that may require cleanup before the demolition of existing structures and site preparation required for construction of facilities, Building 130 was designated as BRAC Site 7. The study indicated that VOCs, SVOCs, pesticides, metals, and low levels of TPH were present in soil and groundwater near Building 130. No significant risks were identified; however, the report stated that remediation was needed for soils impacted with TPH above state criteria (Halliburton NUS, 1994b).

From January to March 1995, Law Engineering collected soil and groundwater samples as part of a Site Assessment. The focus of the study was the abandoned underground aviation fuel line system. The soils indicated TPH contamination and the groundwater data indicated a broader distribution of contamination types. The data appeared to indicate that multiple releases of jet and gasoline-grade fuels have occurred at several different locations over time in the area. The presence of free product was also observed at the western end of Building 130 (Law Engineering, 1995).

In June 1995, Law Engineering collected soil and groundwater samples and conducted aquifer testing as part of a Site Assessment addendum. The study was conducted to further evaluate the extent of free-product accumulation, the extent of contamination, and to assess the potential for exposure to subsurface contaminants. TPH and VOC contamination in the soil was found. The groundwater data suggested that while most of the contamination was located along the abandoned fuel piping along Sixth Avenue, multiple releases of jet and gasoline-grade fuels have occurred at several different locations over time in the area. Further investigation of the extent of dissolved-phase groundwater contamination upgradient and downgradient of Building 130 was recommended.

In 2000, Tetra Tech NUS collected groundwater samples as part of the OU1 RI, and petroleum-related compounds and chlorinated VOCs were detected in groundwater. Based on these groundwater data it was decided that Site 90 be addressed separately from OU1, and a RI for Site 90 was initiated in 2001 with the preparation and regulatory approval of the RI Work Plan. Phase I fieldwork for the RI was completed in October 2002, and included groundwater and soil sampling. The Phase I results, and the results of independent groundwater sampling for chlorinated VOCs conducted by the UST Program, indicated that the chlorinated VOC plume in the Hangar 130 area extended further downgradient than previously thought. Consequently, a Phase I RI Interim Report was prepared that recommended that a Phase II investigation be performed to determine the full extent of the chlorinated VOC plume in the surficial aquifer (CH2M HILL, 2003c). The Phase II RI investigation consisted of the sampling of approximately 60 monitoring wells along the flightline area extending from Site 90 to the northwest, and was performed in October 2003. Based on the results of the Phase II investigation findings, a Phase III investigation was recommended. The Phase III investigation was conducted in April 2005, which included monitoring well installation and additional sampling. The Final Phase II Interim Report was submitted in June 2005.

During examination of the Phase III RI results, it was determined that data gaps still existed with regard to surface water and sediment in the drainage ditch to the northwest of OU14. Based on the data gaps, an ERA is being conducted for OU14 (Site 90) as part of the ongoing Phase III RI.  Because the area that includes Site 90 is urbanized and is comprised of paved surfaces (e.g., parking lots and streets) and buildings, there is no habitat or ecological resources present within the site boundaries being addressed as part of the ERA.  Instead, aquatic receptors in a downgradient stream (water column biota and benthic macroinvertebrates) are being evaluated for potential risk from exposure to CVOC-contaminated ground water that originated from Site 90 and is possibly discharging to surface water and sediment of the stream.  This perennial stream, which is an unnamed tributary of Mill Creek, is approximately 1,400 feet long and 1,000 feet northwest of Site 90.  Surface water and sediment samples were collected in April 2006, and the ERA will be performed in June 2006 according to the NCDENR Guidelines for Performing Screening Level Ecological Risk Assessments within the North Carolina Division of Waste Management (NCDENR, 2003), as well as applicable EPA and Navy guidance (EPA, 1997; EPA, 2001a; Chief of  Naval Operations, 2003; NAVFAC, 2004).  

The Draft OU14 Phase III RI Report is scheduled to be submitted in summer 2006, and will include the results of the ecological and human health risk assessments.

Site History - Operable Unit 14, Site 90
Event	Date
VOC-contaminated groundwater	unknown
Site Characterization and Evaluation Report for BRAC	1994
Site Assessment Report	1995
Site Assessment Addendum	1996
Corrective Action Plan (CAP)	1997
Remedial Action Contract (RAC) Work Plan	2000
Remedial Investigation (RI) Work Plan	2002
Phase I Remedial Investigation Interim Report	2003
Phase II Remedial Investigation Interim Report	2005

 

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Operable Unit 15: Site 82 - Slocum Creek in the Vicinity of OU2 and OU3

Background

During historical investigations at OU2 and OU3 there were constituents that exceeded State water quality standards in samples collected from Slocum Creek. Chemicals were also detected in sediment at concentrations above ecological screening values. For some chemicals, the standards and screening values were exceeded in samples upstream of OUs 2 and 3. Therefore, it was concluded that OU2 and OU3 were not the source(or only source of these chemicals.

Fish Tissue samples were collected from Slocum Creek adjacent to OUs 1, 2, 3, and 4 in 1998 and the results indicated no potential unacceptable risk to human health from fish tissue ingestion(TT, 1998a). In 1999, surface water and sediment samples were collected adjacent to OUs 1, 2, 3, and 4 as part of a screening-level ecological risk assessment(SLERA) in Slocum Creek(TT, 2001). No consistent patterns of contamination were observed. The results suggested a low risk potential, except for metals in sediment at localized areas. A Final PRAP was submitted for OU15 in October 2002, and a NFA ROD was signed in June 2003.

 

 

 

Preliminary Screening Areas (PSAs)

The sites described in this section have been identified by the pending FFA as requiring desk-top audits. These sites may have been previously referred to as POEIs. POEI terminology has been retained for documents that have already been produced.

 

POEIs 22 and 23—Radioactive Waste Storage Areas #1 and #2

POEI 22 is located near Buildings 133 and 421, and POEI 23 is located near Building 1424, within NADEP (Figure 3-12). The areas each consist of a concrete pad and curb covered with an overhead roof that is fenced to control site access. These POEIs were identified during February and April 1998 site visits. The areas were historically used to store low-level radioactive solids (aircraft engine and transmission parts).

Consensus was reached by the Tier I Partnering Team in September 2000 to retain these areas as POEIs pending receipt of additional information regarding actual operations at the sites in question. Interviews were conducted with Station Radiological Affairs Support Office personnel and the following information was provided:

·         All operations at these sites were conducted in strict adherence to Standard Operating Procedures for Ionizing Radiation (MCAS Cherry Point INST IR-001 published and maintained by Occupational Safety and Health Division, Naval Aviation Depot, MCAS Cherry Point).

·         The material stored at these POEIs was very low-level radioactive magnesium thorium, and was a byproduct of the manufacture of J79 transfer, rear, and inlet gearbox casings. All parts were machined in Building 133, and waste scrap, millings, etc., were strictly managed in accordance with IAW IR-001 (placed in sealed 55-gallon drums, properly labeled, stored and disposed of by safety office personnel [Code 6.8.810]). By following the Standard Operating Procedure, there was extremely low probability for a release at the POEIs. Based on this information, closure of POEIs 22 and 23 was recommended in October 2000 as part of a POEI Closure Document.

In January 2001, the EPA responded by letter to the POEI Closure document (EPA, 2001b). The letter indicated that the EPA was waiting on feedback from its radiological support staff and was not yet able to provide concurrence on the proposed closure of Radioactive Waste Storage Areas #1 and #2 (P-22 and P-23). The EPA also requested a copy of the Standard Operating Procedures for Ionizing Radiation.

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Site Screening Areas (SSAs)

The sites described in this section have been identified as requiring screening for possible inclusion in the CERCLA RI/FS process. Some of the sites on this list may have been previously referred to as POEIs. POEI terminology has been retained for documents that have already been produced.

 

POEI 35a—High Power Engine Run-Up Area and Test Cells

Background

A Decision Document (DD) was signed on June 30, 2004, which documented regulatory concurrence with the NFA recommendation.

POEI 35a consists of the eastern end of Runway 28, near OU6. The runway surface in this area is mostly asphalt, with a number of relatively small concrete pads. The runway represents a topographic high in the immediate area, and is bordered with grassy areas with dense woods beyond. Most of the area is used for engine high power run-up activities, and consists of a series of test pads where aircraft engines are mounted on racks and run at high speeds for maintenance purposes. The southwestern portion of POEI 35a is currently used for experimentation regarding long-term storage and preservation of aircraft. POEI 35a was identified during a 1997 regulator site visit as a potential contaminant source area based on the nature of historical site activities. Shallow groundwater flow at Site 35a generally flows east toward Hancock Creek. The water table is encountered at approximately 11 ft bgs.

 In 1996, soil and groundwater samples were collected at POEI 35a, and TPH, oil and grease, and inorganic constituents were detected in the soil samples (REW, 1996). Lead and a trace of one VOC were detected in the groundwater. Based on these results, a POEI Evaluation was conducted in 1999 that included the collection of soil, groundwater, surface water, and sediment samples. The POEI Evaluation sampling results were presented in the Final POEI Evaluation Report in January 2004 (CH2M HILL, 2004b), which concluded that there had not been a significant release of contaminants to the environment from Site 35a. The detected constituents that exceeded human health screening criteria did not appear to be related to site-specific activities, and NFA was recommended (CH2M HILL, 2001b). The Final POEI Evaluation Report and a Decision Document recommending NFA was submitted in June 2004 (CH2M HILL, 2004c).

Site History—POEI (SSA) 35a
Event	Date
Aircraft engine maintenance/test area	Present
Soil/Groundwater Study	1996
Work Plan for OU6	1999
Evaluation Report	2004
Decision Document (DD)	2004

 

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Site 85—Hobby Shop Disposal Area

Background

A Decision Document (DD) was signed in September 2003, which documented regulatory concurrence with the NFA recommendation.

Site 85 was identified as a waste disposal area, approximately 0.33 acres, located near the eastern shoreline of Slocum Creek (OHM, 1998c). Site 85 is situated immediately west of the base auto hobby shop (OU2, Site 76) (Figure 3-14). Much of Site 85 consists of a relatively flat forested area bordering the tidal open waters of Slocum Creek to the west. In the eastern part of the site, a short slope leads eastward toward the adjoining developed areas (CH2M HILL, 2001).

Site 85 historically contained a significant amount of surface debris that had been disposed of at the site. No records indicating the quantities or types of wastes disposed of at the site are known to exist, nor is it specifically known when disposal activities occurred. The exposed debris included empty 55-gallon drums, empty 5- to 15-gallon steel pails, automobiles, concrete debris, office equipment, rubber tires, fire hoses, steel matting, pipes, a set of metal spectator bleachers, and various other items (OHM, 1998c).

In 1997, site inspections revealed evidence that MCAS Cherry Point residents, including children, had trespassed onto Site 85, and had used the site for play activities. A rope swing was found hanging from a tree. As a result of this discovery, an emergency response action was taken to secure the site with fencing to prevent potential human exposure. A wetlands delineation was completed in 1997 to minimize wetlands impacts during a planned debris removal at Site 85 (B&R, 1988). Debris removal activities were completed in 1998. Approximately 30 to 40 cubic yards of metal and debris were removed from the site (OHM, 1998c).

In 2001, a Site Screening Process (SSP) investigation was conducted at Site 85. The SSP investigation included the collection of soil and groundwater samples to determine if residual contamination remained at the site following the debris removal, and whether groundwater had been impacted by past disposal activities. The SSP Report concluded that there was not significant contamination, and NFA was recommended (CH2M HILL, 2003d). A Decision Document (DD) signed in September 2003 documented regulatory concurrence with the NFA recommendation.

 

Site History—Site 85
Event	Date
Waste Disposal Area—empty drums, automobiles, concrete debris, office equipment, rubber tires, fire hoses, steel matting, pipes and other items were found	unknown
Wetland Delineation report for Site 85	1998
Action Memorandum, Debris Removal	1998
Site Screening Process Work Plan	2001
Site Screening Process Report	2002
Site Screening Area Decision Document	2003

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