2018-16257. National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List: Partial Deletion of the South Valley Superfund Site

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule; notice of intent.

SUMMARY:

The Environmental Protection Agency (EPA) Region 6 is issuing a Notice of Intent to Delete Operable Units 1, 2, and 5 of the South Valley Superfund Site (Site) located in Albuquerque, New Mexico, from the National Priorities List (NPL) and requests public comments on this proposed action. The NPL, promulgated pursuant to section 105 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, is an appendix of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). The EPA and the State of New Mexico, through the New Mexico Environment Department, have determined that all appropriate response actions at these identified parcels under CERCLA have been completed, other than five-year reviews and operation and maintenance activities. However, this deletion does not preclude future actions under Superfund. This partial deletion pertains to Operable Units 1, 2, and 5. The remaining Operable Units 3, 4, and 6 will remain on the NPL and are not being considered for deletion as part of this action.

DATES:

Comments must be received by August 30, 2018.

ADDRESSES:

Submit your comments, identified by Docket ID no. EPA-HQ-SFUND-1983-0002, by one of the following methods:

• http://www.regulations.gov . Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e. on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit http://www2.epa.gov/​dockets/​commenting-epa-dockets.
• Email: [e-mail].
• Mail: Michael A. Hebert, Remedial Project Manager, EPA Region 6, Mail Code—6SF-RL, 1445 Ross Avenue, Dallas, Texas 75202-2733.
• Hand delivery:

○ Michael A. Hebert, Remedial Project Manager, EPA Region 6, Mail Code—6SF-RL, 7th Floor Reception Area, 1445 Ross Avenue, Dallas, Texas 75202-2733.

○ Such deliveries are only accepted during the Docket's normal hours of operation (Monday through Friday, 7 a.m. to 4 p.m.) and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-1983-0002. The http://www.regulations.gov website is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to EPA without going through http://www.regulations.gov,, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in the hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at:

Zimmerman Library, Government Information Department, University of New Mexico, Albuquerque NM 87131, 505.277.9100, Monday-Thursday—7 a.m.-2 a.m., Friday—7 a.m.-9 p.m., Saturday—10 a.m.-6 p.m., Sunday—12 p.m.-2 a.m.

New Mexico Environment Department, Harold Runnels Building, 1190 St. Francis Drive, Santa Fe, NM 87505, 505.827.2855, Monday-Friday—8 a.m.-5 p.m.

FOR FURTHER INFORMATION CONTACT:

Michael A. Hebert, Remedial Project Manager, U.S. Environmental Protection Agency, Region 6, Mail Code—6SF-RL, 1445 Ross Avenue, Dallas, Texas, 75202-2733, [phone], email: [e-mail].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction

II. NPL Deletion Criteria

III. Deletion Procedures

IV. Basis for Intended Partial Site Deletion

I. Introduction

EPA Region 6 announces its intent to delete Operable Units 1, 2, and 5 of the South Valley Superfund Site (Site), from the National Priorities List (NPL) and requests public comment on this proposed action. The NPL constitutes Appendix B of 40 CFR part 300 which is the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), which EPA promulgated pursuant to Section 105 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, as amended. EPA maintains the NPL as those sites that appear to present a significant risk to public health, welfare, or the environment. Sites on the NPL may be the subject of remedial actions financed by the Hazardous Substance Superfund (Fund). This partial deletion of the South Valley Superfund Site is proposed in accordance with 40 CFR 300.425(e) and is consistent with the Notice of Policy Change: Partial Deletion of Sites Listed on the National Priorities List. 60 FR 55466 (Nov. 1, 1995). As described in § 300.425(e)(3) of the NCP, a portion of a site deleted from the NPL remains eligible for Fund-financed remedial action if future conditions warrant such actions.

EPA will accept comments on the proposal to partially delete this site for 30 days after publication of this document in the Federal Register.

Section II of this document explains the criteria for deleting sites from the NPL. Section III discusses procedures that EPA is using for this action. Section IV discusses Operable Units 1, 2, and 5 of the South Valley Superfund Site and demonstrates how the operable units meet the deletion criteria.

II. NPL Deletion Criteria

The NCP establishes the criteria that EPA uses to delete sites from the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted from the NPL where no further response is appropriate. In making such a determination pursuant to 40 CFR 300.425(e), EPA will consider, in consultation with the State, whether any of the following criteria have been met:

i. Responsible parties or other persons have implemented all appropriate response actions required;

ii. all appropriate Fund-financed response under CERCLA has been implemented, and no further response action by responsible parties is appropriate; or

iii. the remedial investigation has shown that the release poses no significant threat to public health or the environment and, therefore, the taking of remedial measures is not appropriate.

Pursuant to CERCLA section 121(c) and the NCP, EPA conducts five-year reviews to ensure the continued protectiveness of remedial actions where hazardous substances, pollutants, or contaminants remain at a site above levels that allow for unlimited use and unrestricted exposure. EPA conducts such five-year reviews even if a site is deleted from the NPL. EPA may initiate further action to ensure continued protectiveness at a deleted site if new information becomes available that indicates it is appropriate. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system.

III. Deletion Procedures

The following procedures apply to deletion of Operable Units 1, 2, and 5 of the Site:

(1) EPA consulted with the State of New Mexico before developing this Notice of Intent for Partial Deletion.

(2) EPA has provided the State of New Mexico 30 working days for review of this notice prior to publication of it today.

(3) In accordance with the criteria discussed above, EPA has determined that no further response is appropriate.

(4) The State of New Mexico, through the New Mexico Environment Department, has concurred with the deletion of Operable Units 1, 2, and 5 of the South Valley Superfund Site, from the NPL.

(5) Concurrently, with the publication of this Notice of Intent for Partial Deletion in the Federal Register, a notice is being published in a major local newspaper, the Albuquerque Journal, http://www.abqjournal.com. The newspaper announces the 30-day public comment period concerning the Notice of Intent for Partial Deletion of the Site from the NPL.

(6) The EPA placed copies of documents supporting the proposed partial deletion in the deletion docket, made these items available for public inspection, and copying at the Site information repositories identified above.

If comments are received within the 30-day comment period on this document, EPA will evaluate and respond accordingly to the comments before making a final decision to delete Operable Units 1, 2, and 5. If necessary, EPA will prepare a Responsiveness Summary to address any significant public comments received. After the public comment period, if EPA determines it is still appropriate to delete Operable Units 1, 2, and 5 of the South Valley Superfund Site, the Regional Administrator will publish a final Notice of Partial Deletion in the Federal Register. Public notices, public submissions and copies of the Responsiveness Summary, if prepared, will be made available to interested parties and included in the site information repositories listed above.

Deletion of a portion of a site from the NPL does not itself create, alter, or revoke any individual's rights or obligations. Deletion of a portion of a site from the NPL does not in any way alter EPA's right to take enforcement actions, as appropriate. The NPL is designed primarily for informational purposes and to assist EPA management. Section 300.425(e)(3) of the NCP states that the deletion of a site from the NPL does not preclude eligibility for future response actions, should future conditions warrant such actions.

IV. Basis for Partial Site Deletion

The following information provides EPA's rationale for deleting Operable Units 1, 2, and 5 of the South Valley Superfund Site from the NPL:

Site Background and History

The EPA ID for the South Valley Superfund Site is NMD980745558. The South Valley Superfund Site is in the southern portion of Albuquerque, in Bernillo County, New Mexico, directly across Interstate 25 from the Albuquerque International Airport and the University of New Mexico Golf Course. The South Valley Superfund Site consists of an area of approximately one square mile proximate to the intersection of South Broadway Boulevard and Woodward Road and is divided into two properties: the former Air Force Plant 83 site and the Univar site. The Air Force Plant 83 site is further divided into two parcels located north and south of Woodward Road known as North Plant 83 and South Plant 83, respectively. Various manufacturing operations occurred at the Air Force Plant 83 site from the 1940s until 1967, when the United States Air Force took ownership of the property and its contractor, General Electric Aircraft Engines (GEA), began manufacturing aircraft engine components at the property. GEA purchased the Air Force Plant 83 in 1983 and continued operations until October 1997, when North Plant 83 was closed, and until October 2010, when South Plant 83 was closed. Groundwater beneath the Site is in the Santa Fe Group which is comprised of several layers within the formation. The shallow zone aquifer (approximately 175-225 below ground surface [bgs]) beneath the North Plant 83 area has a continuous silty clay layer underneath it and is therefore primarily perched and does not have a uniform flow direction. The shallow groundwater in the South Plant 83 area flows east to west. Unlike North Plant 83, the silty clay layer beneath the South Plant 83 area is discontinuous and therefore is in hydraulic connection with the deeper aquifer zones. The deeper aquifer sand zones (approximately 225-355 bgs, 255-415 bgs, and 415-515 bgs) have discontinuous silts and clays interbedded within them which are not laterally extensive but may limit downward movement through the formation. Groundwater flows generally east to west in all the deeper aquifer zones.

Groundwater contamination was first suspected in the late 1970s in two municipal wells—San Jose No. 6 and San Jose No. 3. The wells were taken out of service after subsequent sampling indicated contamination. Groundwater monitoring results in the vicinity of the wells indicated the potential for a number of sources, including several industrial operations located in close proximity to the contaminated wells. When the Site was proposed to the NPL on December 30, 1982, (47 FR 58476), it was the number one priority of the State of New Mexico. EPA finalized the NPL listing on September 8, 1983, (48 FR 40658).

The Operable Units at the South Valley Superfund Site are as follows:

Operable Unit 1 (OU1) (included in partial deletion)—OU1 consists of the City of Albuquerque San Jose 6 (SJ-6) and San Jose 3 (SJ-3) wells, which were contaminated with volatile organic compounds (VOCs). EPA signed the Record of Decision (ROD) for OU1 on March 22, 1985 but did not identify a Potentially Responsible Party (PRP). The remedial goal was to eliminate the threat to human health posed by introducing water from the San Jose 6 and San Jose 3 wells into the City of Albuquerque drinking water supply. The objective was achieved by EPA replacing wells SJ-6 and SJ-3 with the Burton No. 4 well, which was completed in April 1987.

Operable Unit 2 (OU2) (included in partial deletion)—The remedial goals of OU2 were to eliminate the conduit(s) for contaminant migration from the shallow to the deeper aquifers and to restrict groundwater use under the Site. EPA signed the OU2 ROD on September 30, 1988 and identified GEA as a PRP. GEA implemented the remedial action by plugging SJ-6 and SJ-3 and any shallow wells that could act as conduits for contaminant transport from the shallow to the deeper aquifers, restricting groundwater use, and implementing groundwater monitoring. GEA integrated the OU2 groundwater monitoring program into Operable Unit 6 and continues the monitoring program today.

Operable Unit 3 (OU3)—The remedial goal of OU3 included reducing the concentrations of site-related VOCs in groundwater to acceptable levels (aquifer restoration) via a pump-treat-injection system. EPA signed the ROD on June 28, 1988 and identified Univar as the Potentially Responsible Party. Univar initiated groundwater recovery system in April 1992 and a vapor recovery system in November 1999. Univar shut off both systems in November 2006. Subsequent monitoring has shown that the groundwater and vapor recovery systems reduced the dissolved chlorinated VOC concentrations to levels below and compliant with applicable or relevant and appropriate requirements as defined in the ROD. On June 10, 2014, the EPA acknowledged that Univar completed all requirements of the Consent Decree dated March 27, 1990, as they relate to the constituents of concern in groundwater identified in the ROD and the subsequent Explanation of Significant Differences dated September 26, 2006, except for addressing 1,4-dioxane contamination. The EPA acknowledged that Univar is addressing 1,4-dioxane in groundwater at OU3 pursuant to Section XVI(D) of the above Consent Decree.

Operable Unit 4 (OU4)—OU4 consists of the vadose zone at the Univar site. As the PRP, Univar was required to investigate the soil around a pit on its property to establish the source of the solvents under their plant. The investigation found no evidence in the vadose zone that a release occurred at this location. EPA signed the ROD on June 28, 1988 and specified No Further Action.

Operable Unit 5 (OU5) (included in partial deletion)—OU5 consists of the unsaturated and saturated portion of the shallow zone aquifer at North Plant 83 and South Plant 83. EPA signed the ROD on September 30, 1988, and identified GEA as the PRP. The remedial goals for this operable unit were remediating shallow zone groundwater and eliminating source materials via enhanced dewatering, soil flushing, and soil vapor extraction (SVE) to result in aquifer restoration. GEA conducted soil vapor surveys and collected soil borings in the South Plant 83 area and the North Plant 83 area to identify VOC contamination. The result of these investigations indicated that the concentrations of VOCs would best be remediated using SVE. GEA operated SVE systems at the North Plant 83 and South Plant 83 areas in 1992 and 1993. Prior to remediation, the groundwater contamination encompassed approximately twelve acres at North Plant 83 and approximately seven acres at South Plant 83. GEA initiated shallow groundwater recovery systems at the North Plant 83 and South Plant 83 areas in May 1994 and completely shut down the groundwater recovery systems in July 2010. GEA completed compliance groundwater monitoring and on September 22, 2014 requested closure of OU5 stating that GEA had satisfactorily completed all requirements of the Administrative Order dated July 3, 1989. All wells and infrastructure associated with the OU5 groundwater treatment system have been plugged and abandoned or removed as approved by EPA.

After the closure of South Plant 83 in October 2010, GEA performed additional remedial activities associated with OU5 soils. Specifically, GEA performed investigations within the North Plant 83 and South Plant 83 building footprints and excavated and disposed of hexavalent chromium contaminated soil from the East and West Tank Line area in South Plant 83. In addition, GEA filed a deed restriction in the Bernalillo County records covering areas where semi-volatile organic compounds (i.e., polyaromatic hydrocarbons) or hexavalent chromium contamination remained above industrial soil screening levels.

Operable Unit 6 (OU6)—OU6 consists of the deep aquifer at North Plant 83 and South Plant 83. EPA signed the ROD on September 30, 1988 and identified GEA as the PRP. The remedial goals of OU6 are hydraulically containing the plume to protect the City of Albuquerque's water supply wells and reducing the concentrations of site-related VOC compounds in groundwater to acceptable levels (aquifer restoration). The original plume was approximately 100 acres in size but as of 2018, only two wells have constituents above cleanup levels. The groundwater remediation system at OU6 began operation in March 1996. Remedial action activities have hydraulically contained the plume and shrunk it significantly from its former volume and mass. To date, over 7.5 billion gallons of contaminated water have been recovered, treated, and reinjected back into the deep aquifer.

The South Valley area of Albuquerque has experienced ongoing development and redevelopment for decades. The proposed extension of Sunport Boulevard from east of Interstate 25 to west of Interstate 25, if constructed, is expected to spur local economic growth and redevelopment.

Remedial Investigation and Feasibility Study

Operable Unit 1 (OU1)—Other than the sampling that established that San Jose No. 6 and San Jose No. 3 municipal water supply wells had been impacted, there was no remedial investigation performed for OU1. Upon detection of contamination, the City of Albuquerque discontinued use of the water supply wells. Subsequently, the EPA, the City of Albuquerque, and other stakeholders conducted several meetings to discuss potential sites for a replacement municipal well, which culminated in the final design and ultimate installation of a replacement municipal water supply well, Burton Well No. 4. In addition, a remedial investigation was initiated which provided information utilized to develop remedial activities for the remaining operable units at the Site.

Operable Unit 2 (OU2)—GEA conducted a remedial investigation for OU2 because of the contamination identified in OU1. As part of the remedial investigation, GEA compiled existing investigative information and collected additional soil, groundwater, surface water, and sediment information associated with the one-square-mile boundary area of the South Valley Superfund Site. In addition, GEA identified contamination associated with several different sources. Based upon the remedial investigation data, GEA determined in the feasibility study that contaminated groundwater in the shallow zone was potentially migrating into the intermediate zone throughout the Site through improperly constructed groundwater wells. The contaminants of concern identified in the remedial investigation were VOCs, with the main contaminant being trichloroethylene (TCE).

Operable Unit 5 (OU5)—GEA conducted a remedial investigation for OU5 because of the contamination identified in OU1. As part of the remedial investigation GEA, compiled existing investigative information and collected additional soil, groundwater, surface water, and sediment information associated with the one-square-mile boundary area of the South Valley Superfund Site. Further, GEA identified contamination associated with several different sources. The contaminants of concern identified in the remedial investigation were VOCs, with the main contaminant being TCE.

Based upon the remedial investigation data, GEA determined in the feasibility study that OU5 soil contamination occurs in areas associated with the two areas, North Plant 83 and South Plant 83, and groundwater contamination occurs in the shallow aquifer below portions of both the North Plant 83 and South Plant 83 areas. GEA also identified groundwater contamination comprising of similar constituents of concerns as in OU5 in several other hydrogeological units beneath the Site, which are addressed in OU6.

After the closure of South Plant 83 in October 2010, GEA performed additional remedial activities associated with OU5, including soil investigations within the North Plant 83 and South Plant 83 building footprints. GEA identified 68 separate areas as a potential concern with 41 of these locations being identified for investigation. In addition, GEA sampled soil borings for VOCs, semi-volatile organic compounds, polychlorinated biphenyls, and selected metals. GEA did not detect VOCs above industrial soil screening levels and did not detect any polychlorinated biphenyls. GEA detected semi-volatile organic compounds (i.e., polyaromatic hydrocarbons) and hexavalent chromium in a few of the 41 locations investigated. In addition, GEA inspected, investigated, and cleaned out sanitary sewer lines for both North Plant 83 and South Plant 83. While GEA detected concentrations of metal contaminants in sediments within the sewer lines, it did not identify impacts in the soils adjacent and beneath the sewer lines.

Selected Remedy

Operable Unit 1 (OU1)—EPA signed the ROD for OU1 on March 22, 1985. The selected remedy was installation of a new water supply well to replace the capacity of the contaminated well San Jose No. 6. The remedial goal was to eliminate the threat to human health posed by introducing water from this well into the City of Albuquerque drinking water supply.

Operable Unit 2 (OU2)—EPA signed the ROD for OU2 on September 30, 1988. The selected remedy consisted of cleaning out and sealing abandoned wells that were acting as conduits for contaminant migration, groundwater quality monitoring during and after implementation of any remedial action, and the imposition of access restrictions regarding well construction specifications and depth of completions through the State Engineer's office. The remedial goals were eliminating conduit(s) for contaminant migration from the shallow to intermediate aquifers and preventing the use of contaminated groundwater in the site area.

Operable Unit 5 (OU5)—EPA signed the ROD for OU5 on September 30, 1988. The selected remedy consisted of further investigation to define the extent of soil and groundwater contamination, soil remediation utilizing SVE on portions of North Plant 83 and South Plant 83, groundwater remediation through extraction, treatment with air stripping followed by carbon adsorption, and reinjection into the aquifer for shallow (OU5) groundwater contaminated zones located under portions of North Plant 83 and South Plant 83 along with intermediate/deep (OU6) groundwater contaminated zones on-site and off-site. The remedial goals for OU5 were remediating shallow zone groundwater and eliminating source materials via enhanced dewatering, soil flushing, and SVE. Further, as a result of the investigations performed by GEA after closure of South Plant 83 in October 2010, GEA conducted removal of soil proximate to the East and West Tank Line area in South Plant 83 in 2011.

Response Actions

Operable Unit 1 (OU1)—The United State Corps of Engineers completed a final design for a new municipal water supply well in late 1986. The remedial action performed at OU1 was the replacement of wells SJ-6 and SJ-3 with the Burton No. 4 well, which was completed in April 1987.

Operable Unit 2 (OU2)—GEA completed a final design dated July 20, 1990, that contained plans to install monitoring wells, clean out and plug abandoned wells including the SJ-6 well (OU1), and conduct a groundwater monitoring program. GEA completed the installation of new monitoring wells and the plugging and abandonment of wells that could act as conduits for contaminant transport to lower groundwater zones by the end of 1992. GEA initiated an OU2 groundwater monitoring program, which in 1996 was combined with the OU6 groundwater monitoring program to simplify groundwater monitoring and reporting at the Site. The New Mexico State Engineer's office issued a restriction concerning groundwater well construction within the boundaries of the South Valley Superfund Site on December 19, 1988.

Operable Unit 5 (OU5)—Because the remedial investigation identified both soil and groundwater contamination, the response actions for OU5 were separated by media into soil and groundwater actions. For soils, GEA finalized the remedial design for the SVE systems in late 1991, which EPA subsequently approved on January 24, 1992. GEA installed and operated SVE systems on both the North Plant 83 and South Plant 83 areas. The North Plant 83 SVE system operated for approximately four months from June 1992 to June 1993. The South Plant 83 SVE system operated for approximately five months from October 1992 to March 1993. For groundwater, GEA's contractor, Canonie Environmental, completed a final design dated July 21, 1993, that contained construction details for the remedial systems for the shallow zone groundwater remediation on the North Plant 83 and South Plant 83 areas. The North Plant 83 system initially was comprised of seven extraction wells, and the South Plant 83 system was comprised of three wells. These systems were augmented through their operational lifetime to adapt to changes in groundwater concentrations and flow patterns.

After the closure of South Plant 83 in October 2010, GEA performed additional remedial activities associated with OU5. GEA conducted removal of soil proximate to the East and West Tank Line area in South Plant 83 in 2011. Approximately 3.5 tons of contaminated soil and concrete were removed and transported for final disposal at an off-site hazardous waste disposal facility. Following removal, GEA backfilled the area with clean fill and capped the area with a five-inch-thick, 3,000 pounds/square inch layer of reinforced concrete. GEA filed a deed restriction in the Bernalillo County records covering areas where semi-volatile organic compounds (i.e., polyaromatic hydrocarbons) or hexavalent chromium contamination remained present above industrial soil screening levels. GEA removed approximately 1,750 feet of primary 4-inch to 8-inch diameter cast iron process sewer lines, 435 feet of similar smaller branch lines, and seven manholes and disposed these materials at a Resource Conservation and Recovery Act treatment, storage, and disposal facility. Finally, GEA cleaned and abandoned in place the South Plant 83 sewer system piping and plugged the connection to the City of Albuquerque sewer system.

Cleanup Levels

Operable Unit 1 (OU1)—There were no cleanup levels established for OU1, as the remedy was simply replacement of a municipal water supply well to replace the capacity lost by the contaminated SJ-6 well.

Operable Unit 2 (OU2)—There were no cleanup levels established for OU2, as the remedy was simply the installation of additional groundwater monitoring wells, the plugging and abandonment of wells that could act as conduits for contaminant transport to lower groundwater zones, the imposition of access restrictions regarding well construction specifications and depth of completions through the State Engineer's office, and the establishment of a groundwater monitoring program to obtain data concerning groundwater contamination.

Operable Unit 5 (OU5)—The investigations and remediation work for OU5 was separated by media into soil and groundwater work. For soil, the ROD required the utilization of SVE for soil remediation but did not specify cleanup levels. The ROD stated, “Soils treatment will continue until the vapor extraction system ceases to produce volatile contaminants and will be followed by sampling to confirm soil remediation.” GEA obtained post remediation soil samples after the SVE systems ceased operations and proposed cleanup levels for soils in April 1993. The proposed cleanup levels considered soil exposure pathways including dermal contact, inhalation, and ingestion (i.e., by children ages 2 to 6) as well as the potential for contaminants to leach from soil into groundwater that would exceed drinking water standards. GEA based the cleanup levels on the assumption of an operating manufacturing facility with restricted access but also on the worst-case exposure scenario that the site could be converted to residential use. During a meeting with GEA on November 2, 1993, EPA verbally agreed to the proposed cleanup levels. In a letter dated June 21, 1994, EPA indicated that the levels of contaminants found in the soils were below limits that required removal. In addition, out of an abundance of caution, as part of the 2017 Remedial Action Report for OU5, GEA performed a comparison of the post remediation soil concentrations to the EPA Industrial and Residential Soil Screening Levels (November 2015) which indicated all the post soil remediation soil concentrations were below the EPA Industrial and Residential Soil Screening Levels. For groundwater, the ROD specified that cleanup levels would be maximum contaminant limits from the Safe Drinking Water Act and levels in the New Mexico Water Quality Control Commission regulations, whichever was more stringent. These levels were updated in an Explanation of Significant Differences dated October 16, 2006, which added a level for tetrachloroethylene promulgated under the Safe Drinking Water Act in 1992. GEA implemented and conducted a groundwater monitoring program throughout the operation of the shallow zone groundwater remediation systems. After six years of monitoring indicating that none of the off-site wells of the North Plant 83 system well network exceeded cleanup levels, EPA approved closure of the off-site wells and conveyance system. GEA flushed, cleaned, and abandoned conveyance piping in place and plugged and abandoned wells in 2010. One on-site well associated with the North Plant 83 system remained slightly above cleanup levels. In 2010, GEA performed in-situ chemical oxidation around this well which subsequent sampling confirmed that contaminant concentrations fell and remained below cleanup levels. The South Plant 83 system experienced a similar history to the North Plant 83 system. By 1999, all wells associated with the South Plant 83 system except for two wells were below cleanup levels. By 2006, only one well had concentrations above cleanup levels. Like the North Plant 83 system, GEA performed in-situ chemical oxidation in 2010 around this well, which subsequent sampling confirmed that contaminant concentrations fell below cleanup levels shortly after the in-situ treatment and remained below cleanup levels through 2012.

After the closure of South Plant 83 in October 2010, GEA performed additional remedial activities associated with OU5. Utilizing investigations results, GEA completed an assessment of the risk for the contaminants identified in the investigation. This assessment indicated that hexavalent chromium contamination in deep soils would not pose a risk to human health and the environment assuming that an impermeable cover remained in place and institutional controls were implemented. The assessment also indicated that the semi-volatile organic compounds (i.e., polyaromatic hydrocarbons) identified in soils would not pose a risk to human health and the environment if the existing concrete cap was left in place. GEA removed soil with concentrations of hexavalent chromium above 50 milligrams per kilogram (mg/kg) but did not remove soil with hexavalent chromium contamination ranging from 5.6 to 50 mg/kg at depths between 5 to 14 feet below the existing concrete slab. GEA filed a deed restriction in the Bernalillo County records covering areas where semi-volatile organic compounds or hexavalent chromium contamination remained above industrial soil screening levels.

Operation and Maintenance

Operable Unit 1 (OU1)—The operation and maintenance concerning the Burton No. 4 replacement well is performed by the City of Albuquerque.

Operable Unit 2 (OU2)—There is no operation and maintenance associated with OU2. The restriction concerning groundwater well construction within the boundaries of the South Valley Superfund Site issued by the New Mexico State Engineer's office on December 19, 1988, remains in effect but is now monitored under OU6. This restriction is not needed and does not affect the protectiveness of the actions performed at OU2.

Operable Unit 5 (OU5)—Since the soil and groundwater remediation systems associated with OU5 have met their associated cleanup levels and have been dismantled, there are no operation and maintenance activities required or ongoing for the OU5 SVE and groundwater remediation systems. In addition, while still in effect, the New Mexico State Engineer's restriction concerning groundwater well construction is no longer required for the protectiveness of the OU5 remedy because groundwater concentrations are below the maximum contaminant limits from the Safe Drinking Water Act and levels in the New Mexico Water Quality Control Commission regulations. After ceasing operations in September 2010 and completing demolition of the South Plant 83 buildings in May 2011, GEA performed investigations of the South Plant 83 property which included evaluating soil impacts near any existing sub-grade foundation features as well as the North Plant 83 and South Plant 83 sewer systems. In addition, GEA cleaned out and abandoned in place the sewer systems. Because of the soil investigation, GEA removed hexavalent chromium contamination near the location of the East and West Tank Line on the South Plant 83 property. Some contamination remained in place and, as a result, GEA filed a declaration of restrictive covenants on September 9, 2014 in the Bernalillo County property records. The declaration identified five areas where semi-volatile organic compounds or hexavalent chromium contamination exceed industrial soil screening levels. The declaration also contained the following: Identification of the abandoned sanitary sewer lines and existing sewer line locations; restriction that the property use is limited to commercial and industrial; restriction that groundwater beneath the site cannot be used; and engineered barriers must remain in place on portions of the property where semi-volatile organic compounds and hexavalent chromium remain above industrial soil screening levels. GEA performs normal property maintenance inspections of the North Plant 83 and South Plant 83 to identify fencing integrity issues and to maintain weed control. These inspections also observe the integrity of the concrete cap over the East and West Tank Line removal area to ensure it is competent. GEA also ensures that the deed restriction remains in the Bernalillo County records.

Five Year Review

Operable Unit 1 (OU1)—A five-year review is not necessary for OU1 because no hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure.

Operable Unit 2 (OU2)—A five-year review is not necessary for OU2 because no hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure. While still in effect, the New Mexico State Engineer's restriction concerning groundwater well construction is no longer required for the protectiveness of the OU5 remedy because groundwater concentrations are below the maximum contaminant limits from the Safe Drinking Water Act and levels in the New Mexico Water Quality Control Commission regulations. In 1996, the OU2 groundwater monitoring program was combined with the OU6 groundwater monitoring program, which is and has been the subject of ongoing five-year reviews associated with the Site. The next five-year review for the Site is due in July 2020.

Operable Unit 5 (OU5)—A statutory five-year review is necessary for OU5 because hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure. OU5 has been the subject of ongoing five-year reviews with the next review due in July 2020. No issues and/or recommendations were identified in the 2015 five-year review for OU5.

Community Involvement

The major community involvement activities associated with the operable units proposed for deletion are as follows:

• Open Houses and Workshops: September 1988; November 1993; July 1995; October 1997; September 1998; November 1999, October 2000; November 2001; January 2013.
• Original Proposed Plan Fact Sheet and Public Meetings: June 1988; July 1988; August 1988; February 1989.
• Public Meetings: October 2000; November 2001.
• Original ROD Fact Sheets: July 1988; November 1988; April 1989.
• Milestone Fact Sheets: May 1989; March 1990; April 1990; June 1990; March 1991; November 1993; June 1995; April 1996; December 2011; January 2013; June 2015; July 2015; June 2018.
• Citizens on Site Mailing List: 590.

Other notable community involvement activities are:

• Pre Five-Year Review public notices published in local newspapers indicating Five-Year Reviews were being initiated.
• Post Five-Year Review public notices published in local newspapers indicating Five-Year Reviews were completed and available in the local repository or from the State or EPA.
• Monthly site status summaries that were made available to the public or more recently, updates to site activities made on the site web page available on the internet.
• September 23, 2010, newspaper article in the Albuquerque Journal concerning the closure of the General Electric plant.
• Discussion of the site at public meetings associated with the Sunport Boulevard Extension from approximately 2010 to the present.
• Fact sheets and public notices have been provided in both English and Spanish.

Determination That the Criteria for Deletion Have Been Met

The implemented remedies have achieved the degree of cleanup or protection specified in the OU1, OU2, and OU5 RODs for the portions of the Site proposed for deletion. The selected remedial action goals and associated cleanup levels for the OU1, OU2, and OU5 portions of the Site proposed for deletion are consistent with EPA policy and guidance. No further Superfund response for the OU1, OU2, and OU5 portions of the Site proposed for deletion are needed to protect human health and the environment. The State of New Mexico, in an August 11, 2017, letter from the New Mexico Environment Department, concurred with the proposed partial deletion of the OU1, OU2, and OU5 portions of the Site from the NPL.

The NCP specifies that EPA may delete a site from the NPL if all appropriate response under CERCLA has been implemented and no further response action is appropriate. 40 CFR 300.425(e)(1)(ii). EPA, with the concurrence of the State of New Mexico, through NMED, believes that this criterion for the deletion of the OU1, OU2, and OU5 portions of the Site has been met and the OU1, OU2, and OU5 portions of the Site no longer pose a threat to public health or the environment. Consequently, EPA is proposing to delete the OU1, OU2, and OU5 portions of the Site from the NPL. Documents supporting this action are available in the Docket.

List of Subjects in 40 CFR Part 300

• Environmental protection
• Air pollution control
• Chemicals
• Hazardous waste
• Hazardous substances
• Intergovernmental relations
• Penalties
• Reporting and recordkeeping requirements
• Superfund
• Water pollution control
• Water supply

Authority: 33 U.S.C. 1321(d); 42 U.S.C. 9601-9657; E.O. 13626, 77 FR 56749, 3 CFR, 2013 Comp., p. 306; E.O. 12777, 56 FR 54757, 3 CFR, 1991 Comp., p. 351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp., p. 193.

Dated: July 19, 2018.

Arturo Blanco,

Acting Regional Administrator, Region 6.