RTI Document No. 6448-012/005/01F Technical Update of Groundwater Contamination Beneath the FCO Building Cleaning Room Area-....- General Electric - Wilmington, NC September 8, 1998 Reviewed by: lj'-ýL 9-4w wki- at-a-Z ~er~ Jeff W. Reynolds, P.G. Research Hydrogeologist Geosciences Department Registered N.C. No. 1075 W. Joseph Alexander, P.G. Manager Geosciences Department Registered N.C. No. 1314
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General Electric - Wilmington, NCSeptember 8, 1998
Reviewed by:
lj'-ýL 9-4w wki- at-a-Z~er~ Jeff W. Reynolds, P.G.
Research HydrogeologistGeosciences DepartmentRegistered N.C. No. 1075
W. Joseph Alexander, P.G.ManagerGeosciences DepartmentRegistered N.C. No. 1314
Update of Soil and Groundwater Contaminationin the FCO Building Cleaning Room Area
General Electric CompanyWilmington, North Carolina
NC Division of Water Quality - Groundwater Section
August 41998 Meeting
Objective:
0 Provide update of project monitoring and assessment activities
Topics of Discussion:
* Project recap
" Review facility location
" Review hydrogeologic conditions
* Review available data
* Discuss conclusions and next steps
August 27, 1998 Meeting Update of Soil and Groundwater Contaminationin the FCO Building Acid Containment Area
GE - Wilmington, NC
Project Recap
A breach in the FCO cleaning room horizontal acid tank containment was identifiedand repaired in September 1996.
0 Assessment activities were performed and shallow (FB-series) wellpoints installed in
study area from October 1996 to January 1997.
* Routine groundwater monitoring was conducted from January to May 1997.
a Decreasing contamination and increasing pH trends were noted in source wellpoint(FB-1) during initial monitoring period.
a Acid containment was resurfaced with acid-resistant coating (August 1997).
* Dry conditions resulted in the drop of water levels below wellpoints from June toDecember 1997.
a NC DWQ was updated during meeting on September 23, 1997 (RTI document No.6448-012/003/0iF).
0 Water levels recovered beginning January 1998; groundwater monitoring wasresumed.
* Increasing contamination and decreasing pH trends noted in source wellpoint (FB-1);suspected to be a result of remobilization/oscillation of an existing pocket ofcontamination.
* Investigated area for indications of possible continuing sources; no continuingsources identified (March - June 1998).
0 Wellpoints FB-2, FB-3, and FB-4 in cleaning room area were removed and Geoprobeborings were drilled in these boreholes.
* Deeper welpoints were installed at FB-2A, FB-3A, FB-4A.
W. Joseph Alexander, P.G.ManagerGeosciences DepartmentRegistered N.C. No. 1314
Update of Soil and Groundwater Contaminationin the FCO Building Cleaning Room Area
General Electric CompanyWilmington, North Carolina
NC Division of Water Quality - Groundwater Section
August 4, 1998 Meeting
Objective:
* Provide update of project monitoring and assessment activities
Topics of Discussion:
" Project recap
* Review facility location
" Review hydrogeologic conditions
" Review available data
" Discuss conclusions and next steps
U
August 27, 1998 Meeting Update of Soil and Groundwater Contaminationin the FCO Building Acid Containment Area
GE - Wilmington, NC
Project Recap
A breach in the FCO cleaning room horizontal acid tank containment was identifiedand repaired in September 1996.
* Assessment activities were performed and shallow (FB-series) wellpoints installed instudy area from October 1996 to January 1997.
0 Routine groundwater monitoring was conducted from January to May 1997.
* Decreasing contamination and increasing pH trends were noted in source wellpoint(FB- 1) during initial monitoring period.
a Acid containment was resurfaced with acid-resistant coating (August 1997).
0 Dry conditions resulted in the drop of water levels below wellpoints from June toDecember 1997.
* NC DWQ was updated during meeting on September 23, 1997 (RTI document No.6448-012/003/0iF).
* Water levels recovered beginning January 1998; groundwater monitoring wasresumed.
0 Increasing contamination and decreasing pH trends noted in source wellpoint (FB-11);suspected to be a result of remobilization/oscillation of an existing pocket ofcontamination.
0 Investigated area for. indications of possible continuing sources; no continuingsources identified (March - June 1998).
* Wellpoints FB-2, FB-3, and FB-4 in cleaning room area were removed and Geoprobeborings were drilled in these boreholes.
a Deeper wellpoints were installed at FB-2A, FB-3A, FB-4A.
* Assessment activities are continuing.
Exhibit 1. Location of Fuel Conponents Operation (FCCO) BuildingGenera Electric -Wilnigton
F- r -- i*-- l, -- -- I -, F *, -- E--- 8-* F I - F- I- V F [ F V
FB-212A
Vertical Ducts
Plant North
( Bodng/Wellpoint Locationand ID Number
Containment Breach Location(discovered and repairedSeptember 1996)
0 Sump Breach Location(repaired August 1997)
Note: Acid tank containmentwas resurfaced August 1997and reinspected July 1998.
Note Waer-table cntours preparedusing arnual interpolationmethod.Alternate interpretations are possible.
* Well F-2A is screened in the loversuwficial aquifer and wvas not includedin the evaluation.
-D FCOF-22
Scale:I inch = 300 feet
0 150 300
Feet
E15"NM80
E170000
Plant North
36.0
35.5
35.0 q\ -~-
(0
2U
34.5
34.0
33.5
33.0
32-5
32.0
- - -0- - *FB-1
0 oo G 0oo0 o 0 CIo 00 . :0, , i,,... -/-• -
0 '0 0 0 00
* Replacement (deepeni g)of wellpoints FB-2,
0 0 FB-3, and FB-4
(6/23/98)
Note: 1. The depth of FB-3 was measured on 2/5/98 to be 0.43 feet shallowerthan the depth measured When.installed..2. Open symbols indicate water-table elevation is below bottom of wellpoint:symbol is plotted at the elevation of the wellpoint bottom.
Location of soil samples field-screened for pH and nitrate. Strip-
@ measured nitrate levels shown "(ppm as NO,). Field analyses byRTI using test strips.
Note: All water samples analyzed by RTI's Center for
Environmental Measurements and Quality Assurance
Exhibit 9. Results of FB-Exploratory Borings - FCO:Cleaning Room Area,':
August 27, 1998 Meeting Update of Soil and Groundwater Contaminationin the FCO Building Acid Containment Area
GE - Wilmington, NC
Conclusions and Next Steps
Conclusions:
" Changes in groundwater quality beneath the FCO cleaning room were observed sincerecovery of the water levels beneath the building.
" The changes in water quality may be a result of remobilization/oscillation of an existingpocket of contamination.
" Three of the FB-series wellp.ýints have been deepened so that monitoring beneath theFCO cleaning room area can continue during dry periods.
* The surficial aquifer beneath the cleaning room area has a saturated thickness ofapproximately 5 feet.
* The presence of a clayey semiconfining unit has been confirmed beneath the FCOcleaning room area, therefore impact to the principal aquifer is not expected.
" Groundwater is expected to eventually flow from beneath the FCO building north-northeast toward effluent channel.
* There is little to no apparent risk to human health associated with the FCOgroundwater conditions.
Next Steps:
Continue evaluation of potential sources of groundwater contamination in cleaningroom area.
Continue monitoring of indicator parameters in FB-series wellpoints and F-series wells.
Conduct short-term pumping tests of well FB-4A.
Assessment activities are continuing.
APPENDIXAnalytical Results, FCO Wellpoint Series
units are mg/L
Wellpoint FB-IDate pH Nitrate (as N) Fluoride Cr Zr Cu Ni Sn