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RAP |
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Appleton Electric |
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Columbus |
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Public Notice Documents |
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Remedial action approval |
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April 5, 2018 |
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May 6, 2018 |
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PUBLIC NOTICE
PROPOSED REMEDIAL ACTION DECISION
FORMER EGS ELECTRICAL GROUP – APPLETON ELECTRIC LLC SITE
Nebraska Department of Environmental Quality
Land Management Division
Remediation Section
Notice is hereby given pursuant to Neb. Rev. Stat. § 81-15, 185.01 that the Nebraska Department of Environmental Quality (NDEQ) is proposing approval of the Remedial Action Plan (RAP) at the Former EGS Electrical Group – Appleton Electric LLC Site, 2500 East 23rd Street, Columbus, Nebraska. The site is located in the northeast quarter of Section 22, Township 17 North, Range 1 East, Platte County, Nebraska.
The groundwater at this site has been contaminated with trichloroethene as a result of previous operations. The NDEQ has assigned the groundwater pollution event at this site a Remedial Action Class 2 (RAC-2). RAC numbers are used to prioritize the groundwater pollution events with one (1) being the highest priority and three (3) being the lowest priority. The proposed final cleanup levels for trichloroethene and its breakdown products are shown in Table 1. The NDEQ is proposing a combined remedy of direct in situ treatment and monitored natural attenuation. A fate and transport groundwater model will be used to determine the extent of in situ treatment, and will be validated by performance monitoring data. A sub-slab depressurization system will be installed in the existing building at the site to limit the potential for vapor intrusion. Additionally, institutional controls will be developed to restrict land use to commercial/industrial, prohibit the use of groundwater for drinking water or irrigation water supplies, and require continued operation and maintenance the proposed sub-slab depressurization system.
Any person may receive additional information, submit written comments regarding the proposed actions, or request a public hearing, in writing, on or before May 6, 2018. A request for hearing must state the nature of the issues to be raised and all arguments and factual grounds supporting such position. If the Director grants a public hearing, the hearing will be advertised by public notice at least 30 days prior to its occurrence. Comments and requests should be mailed to: Mr. David Haldeman, Land Management Division, Nebraska Department of Environmental Quality, P.O. Box 98922, Lincoln, NE 68509-8922.
The proposed RAP and supporting documents are available for inspection at the office of the NDEQ at 1200 N Street, Suite 400, The Atrium, Lincoln, Nebraska. These materials may also be viewed online at http://deq.ne.gov/ by selecting “Public Notices,” or by accessing the Enterprise Content Management Portal at https://ecmp.nebraska.gov/publicaccess/viewer.aspx?&MyQueryID=340, using NDEQ Facility Number “39131” and Program “RAP.” Please notify the NDEQ if alternate formats of materials are needed by April 21, 2018. Individuals requiring special accommodations or alternate formats of materials should notify the NDEQ by calling (402) 471-2186. TDD users should call (800) 833-7352 and ask the relay operator to call the NDEQ at (402) 471-2186. Further information may be obtained from Mike Felix, Remediation Section, (402) 471-4210.
FACT SHEET
PROPOSED REMEDIAL ACTION DECISION
FORMER EGS ELECTRICAL GROUP – APPLETON ELECTRIC LLC SITE
The Nebraska Department of Environmental Quality (NDEQ) is providing public notice of its intent to approve the Remedial Action Plan (RAP) at the Former EGS Electrical Group – Appleton Electric LLC Site. This fact sheet provides background information on the site, a summary of groundwater contamination, a description of the proposed action, a description of the public participation procedures, and the NDEQ contact person.
Site Location: The Former EGS Electrical Group – Appleton Electric LLC Site is located at 2500 East 23rd Street, Columbus, Nebraska. The site is located in the northeast quarter of Section 22, Township 17 North, Range 1 East, Platte County, Nebraska.
Groundwater Contamination: The groundwater at this site has been contaminated as a result of previous operations. The primary contaminant of concern detected in groundwater is trichloroethene. The NDEQ compared contaminant concentrations detected in groundwater to Maximum Contaminant Levels (MCLs) to determine the significance of the contamination. MCLs are established by Nebraska Title 118 – Groundwater Quality Standards and Use Classification, Chapter 4.
The only dissolved contaminant found to be above the MCL is trichloroethene.
There are three potential exposure pathways at this site: ingestion of and dermal contact with contaminants in groundwater, and inhalation of volatilized contaminants via vapor intrusion. There is no current human exposure to contaminants in groundwater because there are no potable wells installed within the footprint of the contaminant plume. There is no current human exposure to volatilized contaminants via vapor intrusion because the indoor air sample did not contain any contaminants at concentrations exceeding exposure criteria for industrial indoor air.
Groundwater Remedial Action Class: The NDEQ assigns a Remedial Action Class (RAC) to a groundwater contamination event to determine the importance of remedial action based, in part, on the use of the groundwater in the area (Title 118, Appendix A, Step 8). Groundwater that is being used as a public drinking water supply is assigned the highest remedial action class of RAC-1. The Department typically requires extensive cleanup of groundwater that is classified as RAC-1. When the use of groundwater in the area is more limited, the groundwater is assigned a remedial action class of RAC-2 or RAC-3. Generally, groundwater cleanup will be less extensive for these classifications.
The pollution event for this site has been classified as a RAC-2, because it has impacted a Class GB aquifer (potential for being used as a public or private drinking water supply), and because there are no domestic wells within 500 feet of the contamination. The NDEQ is proposing the final cleanup levels for trichloroethene and its breakdown products, shown in Table 1.
| Groundwater Concentration |
Trichloroethene | 5 µg/L |
cis-1,2-Dichloroethene | 70 µg/L |
trans-1,2-Dichloroethene | 100 µg/L |
1,1-Dichloroethene | 7 µg/L |
Vinyl Chloride | 2 µg/L |
µg/L - micrograms per liter
Based on Nebraska Title 118 Maximum Contaminant Levels |
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Remedial Action Objectives: Remedial Action Objectives (RAOs) are statements that define qualitative and quantitative goals that are to be achieved for the contaminants identified at the site. RAOs provide the framework from which potential remedial actions are evaluated which will achieve the objectives. The proposed RAOs for the Former EGS Electrical Group – Appleton Electric LLC Site are to restore the aquifer and prevent exposure of current or future groundwater receptors to contaminant concentrations greater than MCLs.
Proposed Remedial Actions: The NDEQ is proposing a combined remedy of direct in situ treatment and monitored natural attenuation. A fate and transport groundwater model will be used to calculate the natural assimilative capacity of the aquifer and define direct treatment thresholds such that the proposed final cleanup levels are achieved within a reasonable timeframe (i.e., 20 to 30 years). Any areas of the contaminant plume that exceed the assimilative capacity predicted by the model will be directly treated using an in situ technology. Performance monitoring will be used to validate the groundwater model and confirm that contaminant concentrations remain below the direct treatment thresholds. A sub-slab depressurization system will be installed in the existing building at the site to limit the potential for vapor intrusion. Additionally, institutional controls will be developed to restrict land use to commercial/industrial, prohibit the use of groundwater for drinking water or irrigation water supplies, and require continued operation and maintenance the proposed sub-slab depressurization system.
Public Participation Procedures: Any person may receive additional information, submit written comments regarding the proposed actions, or request a public hearing, in writing, on or before May 6, 2018. A request for hearing must state the nature of the issues to be raised and all arguments and factual grounds supporting such position. If the Director grants a public hearing, the hearing will be advertised by public notice at least 30 days prior to its occurrence. Comments and requests should be mailed to:
Mr. David Haldeman
Land Management Division
Nebraska Department of Environmental Quality
P.O. Box 98922
Lincoln, NE 68509-8922
Contact: The proposed RAP and supporting documents are available for inspection at the office of the NDEQ at 1200 N Street, Suite 400, The Atrium, Lincoln, Nebraska. These materials may also be viewed online at http://deq.ne.gov/ by selecting “Public Notices,” or by accessing the Enterprise Content Management Portal at https://ecmp.nebraska.gov/publicaccess/viewer.aspx?&MyQueryID=340, using NDEQ Facility Number “39131” and Program “RAP.” Please notify the NDEQ if alternate formats of materials are needed by April 21, 2018. Individuals requiring special accommodations or alternate formats of materials should notify the NDEQ by calling (402) 471-2186. TDD users should call (800) 833-7352 and ask the relay operator to call the NDEQ at (402) 471-2186. Further information may be obtained from Mike Felix, Remediation Section, (402) 471-4210.
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