Five-Year Review Report Landfill & Development Company Superfund Site
Burlington County, New Jersey
Prepared by:
United States Environmental Protection Agency Region 2
Emergency & Remedial Response Division New York, New York
July 2011
Table of Contents
Five-Year Review Summary Form .................................................................................................. 2
I. Introduction ...................................................................................................... ' ............. : ............. 5
II. Site Chronology ......................................................................................................................... 5
III. Background............................................................................................................................... 5 Site Location and Description ............................................................................................. 5 Topography..................................................................................................................... : .... 6 Geology/Hydrogeology ........................................................................................................ 6 Surface Water Features ...............................................................................6 Land and Resource Use .............................. ~ ........................................................................ 7 History of Contamination .................................................................................................... 7 Initial Response ................................................................................... : ................................ 7 Basis for Taking Action ................................................................... : ................................... 8
IV. Remedial Actions ..................................................................................................................... 8 Remedy Selection ..................................... ; .......................................................................... 8 Remedy Implementation ................. : ................................................................................... 10 Remedy Operation and Maintenance ............................................................. 12
V. Progress Since the Last Review ............................................................................................... 12
VI. Five-Year Review Process ..................................................................................................... 12 Community Notification and Involvement.. ...................................................................... 13 Document Review ........................................................................ : .................................... 13 Data Review ...................................................................................................................... 13 Site Inspection ................................................................................................................... 15 Interviews .......................................................................................................................... 16
VII. Remedy Assessment ........................................................................................... : ................. 16 Question A ......................................................................................................................... 16 Question B ......................................................................................................................... 18 Question C .................................... : ....... : ................... -.... ' ................... ~ ................................. 19 Technical Assessment Summary ....... '............................................................. .20
.VIII. Recommendations and Follow-Up Actions ......................................................................... 20
IX. Protectiveness Statement ......................................................................................................... 20
X. Next Review:· ........................................................................................................................... 21
EXECUTIVE SUMMARY
This is the first five-year review for the Landfill & Development Company Superfund site, located in the Townships of Mount Holly, Eastampton, and Lumberton in Burlington County, New Jersey. The major components of the selected remedy included: construction and operation of a groundwater extraction system to provide hydraulic contai~ent; construction and operation of an enhanced aerobic bioreactor in one of the landfill cells; continued maintenance of the existing final cover system on the landfill; continued landfill leachate and gas collection and disposal; decommissioning of residential water supply wells; and long-term monitoring for groundwater. This five-year review found that the remedy is functioning as intended by the decision document, and is protecting human health and the environment. Institutional controls are in place in the form of the approved landfill closure plan and the groundwater Classification Exception Area established by the New Jersey Department of Environmental Protection.
Five-Year Review Summary Form
SITE IDENTIFICATION
: Landfill & Develo Site
NPL status: X Final 0 Deleted 0 Other Icn,ol"'it\l\
Remediation status
Multi date: Se
Are site related properties currently in use? 0 YES ALL 0 YES SOME X NO NONE 0 N/A GW
Tribe 0 Other Federal
Author affiliation: EPA
: 12/22/2010
Type of review: X Post-SARA Statutory 0 Pre-SARA or post-SARA Policy 0 NPL-Removalonly o Non- L Remedial Action Site 0 ional Discretion
Review number: X 1 Triggering action:
o Previous Five-Year Review Report 0 Other (specify) X Actual RA Onsite Construction or RA Start at au # o Construction Com
Dyes Xno
Does the rem nrl'.t",,·t the environment? X o no * ["aU" refers to operable unit.] 'c
** [Review period should correspond to the actual start and end dates of the Five-Year Review in WasteLAN.]
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Five-Year Review Summary Form, cont'd.
Issues, Recommendations and Follow-up Actions:
This report does not identify any major issues at this site needed to protect public health and/or the environment that is not addressed by the remedy selected in the site decision documents as routinely operated, modified, maintained and adjusted over time.
The existing actions should continue: groundwater extraction with a portion of extracted water diverted to recharge cell 9; process monitoring at monthly frequency; implementing the LongTerm Monitoring (L TM) program at current frequency; and, monitoring contamination levels in extraction well RW-3 to determine whether volatile organic compound (VOC) concentrations become low enough to consider the well for shutdown. The L TM Plan should be reviewed to ensure that the data being collected are sufficient to determine whether aquifer restoration can be achieved.
Protectiveness Statement:
Because the remedial actions at the L&D Company Site are protective, the site is protective of human health and the environment. The landfill is capped and fenced, hydraulic containment has been established, and new water supply wells installed and screened in an aquifer not affected by the site for the remaining downgradient residences. Institutional controls are in place in the form of the approved landfill closure plan and the groundwater Classification Exception Area established. by NJDEP. These controls will need to remain in place until contaminant concentrations in groundwater meet the appropriate criteria.
Other Comments:
None.
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(
I. Introduction
The purpose ofthe five-year review is to determine whether the remedy ata site is protective of i~ human health and the environment. The methods, findings and conclusions of reviews are
documented in Five-Year Review reports. In addition, Five-Year Review reports identify issues found during the review, if any, along with recommendations to address them.
This review was conducted pursuant to Section 121(c) of the Comprehensive Environinental Response, Compensation, and Liability Act of 1980, as amended, 42 U.S.C. § 9601 et seq. and 40 C.F.R. 300.430(f)(4)(ii) and with the (Comprehensive Five-Year Review Guidance), OSWER Directive 9355. 7-03B-P (June 2001).
This is the first five-year review for the Landfill and Development Company (L&D) Superfund site, which is located in the Townships of Mount Holly, Eastampton, and Lumberton in Burlington County, New Jersey. The triggering action for this statutory review is the inItiation of the remedial action on July 17,2006. The five-year review is required due to the fact that hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure.
This review was conducted by U.S. Environmental Protection Agency (EPA) Remedial Proj ect Manager (RPM) Douglas Tomchuk. This document will become part of the site file. Reports ,pertinent to this five-year review are listed in Table 2 of the report.
'II. Site Chronology
Table 1 summarizes the relevant site-related events from discovery of contamination to the writing of this first five-year review.
III. Background
Site Location and Description
, The Landfill & Development Company Site is a closed landfill located in Burlington County, New Jersey. Itoccupies portions of the Townships of Mount Holly, Eastampton, and
. Lumberton. The site is located on the north side of Route 38 and is approximately 200 acres in
. size. The closed landfill consists of two sections, the Mount Holly section on the west and the Eastampton section oli the east. In addition to the two landfill sections, the site includes five sediQ1entation ponds, a perimeter road, a leachate collection system, a landfill gas management system, and a closed power plant. The North Branch of Rancocas Creek (hereafter referred to as Rancocas Creek) is located approximately 700 feet north of the landfill boundary. (See Figure 1).
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Topography
Geology/Hydrogeology
The L&D Site is divided into five hydrogeologic units·based on similar hydrologic properties. The units, in descending order from the ground surface, are as follows (see Figure 1): • Mount Laurel/Cape May Sand (MLCMS) aquifer • Upper Wenonah confining unit • Middle Wenonah aquifer • Marshalltown/Lower Wenonah confining unit, and • Englishtown aquifer.
Groundwater flow in all three aquifers is northward, towards Rancocas Creek. The Middle Wenonah and MLCMS aquifers discharge into Rancocas Creek. At times, the MLCMS aquifer north of the Eastampton section of the landfill may also discharge into Smithville Canal. Groundwater also discharges seasonally as groundwater seeps. Vertical hydraulic gradients are downward to the Englishtown aquifer south of the landfill, and upward from the Englishtown aquifer north ofthe landfill (with an increasing upward gradient towards Rancocas Creek).
Portions of the MLCMS aquifer and Middle Wenonah aquifer have been impacted by the landfill. Groundwater in the underlying Englishtown aquifer has not been impacted by the landfill. The greatest concentrations of contaminants in groundwater are found in the Middle Wenonah aquifer in a relatively narrow band downgradient of the eastern portion of the Mount Holly section. This relatively narrow band of higher concentrations is referred to as the "Central Area." Only the Central Area of the Middle Wenonah aquifer is associated with unacceptable levels of risk.
Based on a comparison of historical groundwater levels versus the bottom elevation of landfill contents, groundwater is likely in contact with the refuse in the northwestern portion of the Mount Holly section. here are several other areas with the potential for groundwater to periodically be in contact with the refuse.
Surface Water Features
There are also several surface water features in the vicinity of the site. Rancocas Creek is located north of the landfill and flows in a westerly direction. A man-made canal, known locally as the Smithville Canal, originates at Smithville Lake, and flows (when not stagnant or dry) to the west/northwest. Surface drainage at the landfill is controlled by the topography and a surface water runoff collection system that includes five sedimentation ponds. There are some locations between the landfill and Rancocas Creek where groundwater seasonally discharges to land surface (referred to as "groundwater seeps"). These features should not be confused with seeps of liquid leaching from the landfill itself (referred to as "leachate seeps") which are not present. During wetperiods, numerous groundwater seeps have been observed between the landfill and Rancocas Creek, some with standing. water and others flowing. However, during dry periods, the groundwater seeps are not present.
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Land and Resource Use
To the north of the L&D Site, there are first a number of commercial properties, followed by , several residential properties and then an area of open space (designated Green Acres property)
and Rancocas Creek. To the east are residential properties, and to the west are residential properties and a county children's home. To the south is a combination of commercial/retail properties and farmland. (Please see Figure 2.) .
Groundwater use in the vicinity of the L&D Site is restricted through a Classification Exception Area (CEA) that NJDEP established on May 23, 2008. The CEA restricts use of the upper .aquifers under the site, extending to Rancocas Creek, but does allow use of the uncontaminated Englishtown aquifer. (See Figure 3.)
There were no federally listed or proposed threatened or endangered species found at the site.
History of Contamination
The site operated as a sand and gravel pit from the early 1940s until approximately 1968. The first waste disposal activities at the site are believed to have been initiated in 1962, when the property owner, George Pettinos, began disposing of demolition debris in the Mount Holly section of the landfill. The disposal of demolition debris occurred from 1962 until the late 1960s. During this time period, a 10-foot thick layer of refuse was deposited on what is believed to have been the excavated base of the sand and gravel pit. In 1968, George Pettinos leased the Mount Holly section to Mount Holly Township for use as a landfill, and the landfill began
. accepting industrial and commercial solid waste and sewage sludge. The Landfill and I Development Company (the L&D Company, currently a subsidiary of Waste Management, Inc.) acquired the property in 1971, and began landfilling operations in the Eastampton section of the
. site in 1976. These operations continued until 1981.
Initial Response
The L&D Company operated the landfill until December 31, 1986, when it ceased accepting waste materials after reaching its permitted capacity. The landfill sections were closed in accordance with an approved closure plan, and the constructed closure systems for the entire landfill were approved by NJDEP on May 24, 1995. The engineering controls that are maintained as part of the landfill post-closure requirements include:
• A leachate collection system in the Mount Holly section and in a limited area of the Eastampton section;
• A methane gas collection system;. and • A clay cover system.
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Residents downgradient of the landfill using private wells were provided with bottled water by L&D Company to ensure that they were not potentially exposed to contaminants originating from the site.
Basis for Taking Action
The site was included on the National Priorities List (NPL) in 1983. A Remedial Investigation and Feasibility Study (RIIFS) was initiated by NJDEP in 1986. In 1988, the L&D Company signed an Administrative Order on Consent which included, among other things, completion of the RIlFS. NJDEP selected a remedy for the site and a Record of Decision (ROD) was issued i~ 2004.
The groundwater investigations at the site found that the shallow aquifers (the Mount Laurel/Cape May Sands, and the Middle Wenohah ) were contaminated with volatile organic compounds (VOCs) from the site. VOCs found at the site included: 1,2-dichloroethene, 2butanone, 4-methyl-2-pentanone, acetone, benzene, cis-l ,2-dichloroethene, methylene chloride, toluene, and vinyl chloride.
Elevated metals concentrations are found in groundwater at background wells, and in some cases background groundwater quality exceeds groundwater quality criteria (e.g., aluminum, arsenic, cadmium, chromium, iron, lead, manganese, and thallium), for total and/or dissolved metals. However, sampling results indicate that for some inorganic parameters (including metals) the landfill is causing impacts to groundwater quality, while for other inorganic parameters it is difficult to determine if the landfill is causing impacts to groundwater. Inorganic parameters impacted by the landfill at one or more wells include chloride, hardness, ammonia, total dissolved solids (TDS), iron, lead, manganese, and sodium. Inorganic parameters that mayor may not be impacted by the landfill include ~luminum, arsenic, cadmium, and thallium.
The .cumulative carcinogenic risk from exposure to groundwater in the Central Area of the Middle Wenonah aquifer is 1.7 x 10-2 for the adult/child resident. For this population, the following chemicals have been identified as risk drivers; that is, the risk from exposure through all evaluated pathways exceeds the upper bound of EP A's acceptable level of 1 x 10-4 due to arsenic, 1,2-dichloroethane, benzene, methylene chloride, and vinyl chloride.
The noncarcinogenic hazard index (HI) from exposure to contaminants in the groundwater of the Central Area of the Middle Wenonah aquifer through ingestion, inhalation, and dermal contact is a HI of 230 for the adult/child resident. The risk drivers for this population are: arsenic, 1,2dichloroethane, 2-butanone, 4-methyl-2-pentanone, acetone, benzene, methylene chloride, toluene, and vinyl chloride. Therefore, the Hazard Quotient (HQ) for each of these chemicals exceeds the EPA benchmark of 1.
IV. Remedial Actions
Remedy Selection A Superfund Record of Decision was issued by NJDEP, with EPA concurrence, on September
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30,2004. For the landfill contents, the primary remedial action objective was to maintain the existing engineering controls that accomplish the following:
• Prevent direct contact with landfill contents; • Reduce leaching of constituents to groundwater over time; • Control surface water runoff and erosion; and • Control landfill gas migratio~.
A secondary remedial action objective for landfill contents was to reduce the mass, toxicity, or mobility of potentially hazardous constituents in Cell 9.
For groundwater, remedial action objectives were to:
• Prevent human consumption of groundwater from the MLCMS and Middle Wenonah aquifers between the landfill and Rancocas Creek;
• Achieve remediation goals established for groundwater in the MLCMS and Middle Wenonah aquifers; and
• Avoid and/or minimize negative impacts to human health or the environment (e.g., the wetlands) caused by active remedial measures.
The ROD identified the selected remedy for the site and included:
• Construction and operation of a groundwater extraction system in the Middle Wenonah aquifer in the Central Area to provide hydraulic containment;
• Construction and operation of Enhanced Aerobic Treatment (Cell 9), whereby leachate and groundwater would be recirculated into the landfill along with appropriate air injection to enhance contaminant degradation. Excess water would be discharged to the POTW (publicly owned treatment works) for treatment if necessary;
• Long-term monitoring for groundwater exceeding the remediation goals, including in the Flank Areas not targeted for active extraction and treatment;
• Continued maintenance of the existing final cover system on the landfill; • Continued landfill leachate and gas monitoring, collection, and disposal; • Decommissioning of residential water-supply wells downgradient of the landfill, • Implementation of a Classification Exception Area, and; • Continued maintenance of the site security.
The ROD also included the following language:
Burlington County is in the process of acquiring properties along Rabbit Run and Hand Lane. The County would like to acquire these properties for various reasons, including:
• The dwellings are served by on-site septic systems located in the floodplain or adjacent to Rancocas Creek. These septic systems may be responsible for the
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exceedance of the water quality standard for fecal colifonn in the North Branch of the Rancocas Creek;
• The dwellings are in the floodplain and therefore are subject to frequent flooding; and, .
• These properties lie adjacent to Smithville Park, and the County would like to create a greenway along the North Branch of the Rancocas Creek that would link Smithville Park to other County-owned properties along the Creek and Rancocas State Park.
If the County does not provide written documentation to NJDEP from the Board of Chosen Freeholders of Burlington County within 6 months that the properties will be acquired by March 2006, or otherwise satisfactorily demonstrate to NJDEP that itwill acquire these properties in a reasonable timeframe, the following remedy will also be implemented: '
• Water line extension to Hand Lane and along the western portion ofRabbit Run, downgradient of the landfill.
If the County does provide written documentation to NJDEP that it will acquire these properties in a reasonable timeframe, then the water line extension along the western portion of Rabbit Run downgradient of the landfill will not be installed.
Currently, the residents on Hand Lane and Rabbit Run are provided bottled water by the L&D Company. Those residents will continue to receive bottled water until their property either is acquired by the County or the water line is installed.
Several of the property owners sold their properties to Burlington County, after several extensions to the time frame to install the water line. On September 3,2009, an "Explanation of Significant Differences" (ESD) was issued by EPA involving the residential water supply components of the remedy. The ESD indicated that future water supply to residences on Hand Lane and the western portion of Rabbit Run will be provided by the installation of a new residential water supply well at each of the remaining properties not owned by Burlington County. The water supply wells would be installed in the Englishtown aquifer, which is not impacted by the landfill and not restricted for use by the CEA. Any existing water supply wells on those properties will be decommissioned. The new water supply wells would be in lieu of the public water line extension identified in the ROD.
Remedy Implementation
The Remedial Action Work Plan (RA WP), dated January 26,2006, provided details regarding the remedy design. It also included the rationale and criteria for when certain aspects of the remedy can be discontinued, (e.g., recirculation of groundwater into Cell 9). The RA WP was approved by NJDEP on June 23,2006, subject to four conditions that the L&D Company agreed to implement during the construction and post-construction phases (by letter dated July 3, 2006).
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Installation of extraction wells and associated piezometers began in July 2006. The installation of the groundwater recirculation and air injection piping and equipment began in October 2006. Continuous operation of groundwater extraction with recirculation of extracted water (plus leachate at times) began on February 27,2007.
The air injection phase of the remedy was tested in November 2007, and had intermittent operation during a shakedown period between November 30 and December 10,2007, at which time more continuous. operation of the air circulation was initiated. The air system then operated over a period of approximately 3.5 months. On April 2, 2008, air recirculation was discontinued due to subsurface combustion of waste near air injection well AI-2S. In August 2008, additional air monitoring points were added via direct push technology, and based on temperature and carbon monoxide readings in the vicinity of AI-2S, some subsurface smoldering of waste was still occurring in that area.
When tested in December 2009, the VOC levels in the landfill seemed to be reduced in . comparison to the concentrations measured when the system was operating for an extended period oftime in 2008. The testing results could indicate either ofthe following: (1) there were less VOCs in Cell 9 than in the initial phase of the remedy, as a result ofthe remedy; or (2) the air system may need to operate longer than the several weeks tested in December 2009 to get enough circulation and temperature increase to yield the higher VOCs. In order to attempt to determine which circumstance was more likely, the L&D Company conducted a longer-term air system test in Fall 2010. It was determined that continuing operation of the aeration system would provide limited additional benefit when compared with the cost of system operation. No further operation of the air recirculation system is planned, although extracted groundwater continues to be injected in Cell 9.
The groundwater extraction system continues to operate. In the ROD, groundwater extraction was anticipated to continue for three years after the aerobic treatment was discontinued to achieve the Remediation Goals in the Middle Wenonah aquifer.
The residential water supply components of the remedy (installation of new residential wells and decommissioning of existing wells) were addressed in a RA WP Addendum. The RA WP Addendum was approved by NJDEP in a letter dated July 29,2009.
Several of the residents on Hand Lane and Rabbit Run sold their properties to Burlington County, and those properties are included in the area designated as Green Acres property. By early 2010, it was clear that three residents would not be selling to the County, so permanent
, drinking water supply wells were installed for those residences in Feb,ruary 2010. One· remaining property had a new well installed and tested in August 2010, bringipg the total to four.
, These wells were installed by the L&D Company, with oversight from NJDEP, in the Englishtown Aquifer, which is not affected by the site. Therefore, the alternative water supply component of the remedy is completed.
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Bottled water had been supplied to residents potentially impacted by the landfill from before the ROD was issued. Now that acceptable water is available to all remaining residents, it is no longer necessary for the L&D Company to provide bottled water to the residents.
The landfill property and areas downgradient of the landfill, but still south of Rancocas Creek were designated a Classification Exception Area by NJDEP on May 23, 2008. The CEA does not include the Englishtown Aquifer. A CEA Biennial Certification was completed in May 2010, and the next Biennial Certification is due May 23,2012. The CEA will continue witil groundwater quality standards are achieved. The long-term monitoring program, which began in May 2006, continues to be implemented in accordance with the schedule in the document entitled, "Long-Term Monitoring: L~cations and Frequency" (dated April 15, 2005 plus addendum dated January 16,2006); This plan includes both the Central Area as well as the Flank Areas.
Remedy Operation and Maintenance
The L&D Company operates the groundwater and leachate recovery systems as part of its landfill closure permit. Collected leachate is sent to the local sewage treatment plant for disposal. Landfill gas is collected and flared (methane recovery was discontinued prior to issuance of the ROD because it was no longer economically viable). Groundwater circulation into the bioreactor cell continues, although air addition has been discontinued. The L&D Company continues to conduct long-term monitoring in accordance with the approved Long Term Groundwater Monitoring (L TM) Plan. As part of the L TM, wells ,are sampled at intervals established in the plan, based on the well location. The landfill closure permit requirements continue to be implemented. Site fencing is maintained, the cap inspected and inowed, and the leachate collection system checked. Several flow meters and associated piping have required replacement due to corrosion.
V. Progress Since the Last Review
This is the first five-year review for the site.
VI. Five-Year Review Process
Administrative Components
The five-year review team consisted of Douglas Tomchuk (EPA-RPM), Ed Modica (EPAHydrogeologist), Lora Smith and Becky Ofrane-Hughes (EPA-Risk Assessors), Mindy Pensak (EPA-Ecological Risk Assessor & BTAG), Dave Kluesner (Community Involvement Coordinator) and Glenn Savary (NJDEP Project Manager).
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Community Notification and Involvement
EPA notified the community of its initiation of the five-year review process by publishing a notice in the Burlington County Times on June 1, 2011. The notice indicated that EPA would be conducting a five-year review of the remedy at the Landfill & Development Company Site to ensure that the remedy remains protective of public health and is functioning as designed. The notice included the RPM's address and telephone number for questions related to the five-year review process. In addition, the notice indicated that once the five-year review was completed, the results would be made available to the public at the following location: ,
Burlington County Library 5 Pioneer Boulevard Westampton, NJ 08060
The RPM did not receive any comments in response to the June 1,2011 notice in the Burlington County Times.
Document Review
A list of the documents that were reviewed in the preparation of this review can be found in Table 2.
Data Review
Groundwater data has been collected regularly at the site for process monitoring of the groundwater extraction system and as part of the long-term monitoring plan. These data have been reported in the Remedial Action Progress Reports and the last round of data reported was included the Remedial Action Report dated January 31, 2011.
Based on process performance data, the extraction system is performing as designed, effectively containing dissolved phase VOCs and preventing downgradient migration. Recovery wells have been operating at close to target rates of 6 gallons per minute (gpm) per well. The wells have been periodically rehabilitated to maintain specific capacities above critical levels. The effectiveness of capture is demonstrated by hydraulic gradients and VOC concentration trends at monitoring wells located downgradient of extraction wells. Monitoring wells in the vicinity of RW-IR (a replacement for well RW-l due to fouling) show that the extraction wells reversed hydraulic gradients after commencement of pumping. VOC concentrations at downgradient monitoring wells show decreasing concentrations after pumping began (LDM-21O, LDM-206, and LDM-7).
As a result of groundwater extraction, contaminants downgradient of the central area in the Middle Wenonah and MLCMS aquifer monitoring wells have decreased substantially (see
, Figure 3 for well locations). For example, in well LDM-206, methylene chloride was detected at , 1200 micrograms per liter (ug/L) in 2005, reduced to 38 ug/L in late 2007 and has been nondetect since. Benzene was detected at 110 ug/L in 2006 but has decreased to 3.5 ug/L in the
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latest sampling event. This concentration is still above the New Jersey Ground Water Quality Standard (NJGWQS) of 1 uglL, but below the Federal Maximum Contaminant Level (MCL) of 5 ugiL. Also at LDM-206, 1,2-dichloroethane was detected at 1500 ugiL in 2006 and was reported at 4.7 ugiL in 2010. The groundwater extraction remedy is functioning as intended by the ROD. In the MLCMS aquifer, benzene and chlorobenzene continue to exceed NJGWQS and MCLs, but are limited to the immediate vicinity of the landfill boundary.
The centrally located recovery wells RW-2 and RW-4 have the highest VOC concentrations whereas recovery wells at the edges, RW-1 and RW-3, have much lower VOC concentrations. Since 2007, concentrations of acetone, 2-butanone, 4-methyl-2-pentanone, 1-2,dichloroethane, benzene, and methylene chloride have declined to various degrees. Extraction well RW-2 was . shut-down on March 25, 2009 due to persistently low VOC concentrations. The well will remain in stand-by/shut-down mode unless "trigger concentrations" (benzene> 35 IlgiL or 12,dichloroethane> 20 Ilg/L) are observed in RW-2 or in monitoring well LDM-306.
Observations of the LTM regarding VOCs include the following:
• In the MLCMS aquifer, the pattern ofV,oC impacts has remained the same since prior to the remedy and at the time of the RI sampling in 1999. Concentrations exceeding criteria are limited to benzene and chlorobenzene, and are limited to the immediate '. vicinity of the landfill boundary. Criteria are not exceeded for any VOCs north of the immediate landfill boundary. There are currently higher concentrations of benzene and chlorobenzene observed at LDS-205 (see Figure 3 for LTM well locations) compared to before the remedy, presumably related to the flushing Cell 9 associated with the remedy. It is likely that the groundwater in the vicinity ofLDS-205 is captured by nearby extraction well RW-1R (which is screened deeper), and it is also noted that both benzene and chlorobenzene are non-detect at LDS-206 which is located further downgradient.
• In the Middle Wenonah aquifer, there have been significant concentration reductions for VOCs in the Central Area since prior to the remedy and at the time of the RI sampling in 1999. At LDM-206, concentrations are currently non-detect for most VOCs and only slightly above criteria for 1,2-DCA (4.7 ugll) and benzene (3.5 ug/l), whereas prior to the remedy there were multiple VOCs with concentrations greater than 1,000 ugll. These much lower VOC concentrations at LDM-206 are attributed to the successful hydraulic capture of the most impacted ground~ater that is provided by the remedy extraction. Concentration reductions have also been noted at LDM-7 (on the order of90% reductions in 1,2-DCA and benzene).
oAt LDM-21O, there have been significant reductions of most VOCs such as MEK, acetone, MIBK, and toluene. However, there are relatively stable concentrations of 1,2-DCA (on the order of 10-JO ugll) and benzene (on the order of25-45 ugll), which are the only two VOCs exceeding criteria at this well. These are the same constituents observed at the two outer recovery well locations (RW-2 and RW-4) and these
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concentrations of 1,2-DCA and benzene may reflect the general concentration of the "relatively clean" groundwater at the edges of the remedy capture zone. The other constituents are within the capture zone of the remedy and/or have been sufficiently remediated within the landfill. The concentrations of 1,2-DCA and benzene observed at LDM-210 attenuate significantly by the time the groundwater reaches LDM-206 several hundred feet downgradient (currently less than 5 ug/l for each constituent).
o At 22M, which is just upgradient of the remedy extraction wells, there has also been a very substantial decline in VOC concentrations for many constituents such as MEK and methylene chloride. Since this is upgradient of the extraction wells, it is not due to capture; rather, these concentration declines indicate reduced source strength beneath the landfill. This is likely due to the remedy, but is also due to declining source strength over time due to natural degradation within the landfill that was already occurring prior to the remedy. Again, the most significant VOC concentrations remaining at this well are 1,2-DCAand benzene.
• In the Middle Wenonah aquifer, the concentration patterns in the Flank Areas (see Figure 3 for well locations in the Flank Areas) are similar to those prior to the remedy
. and at the time of the RI sampling in 1999. There are minor exceedances ofjust a few VOC parameters.
• In the Englishtown aquifer, no VOCs exceed criteria, and no VOCs have been detected over the course of the remedy (similar to historic ~esults) .
. Groundwater remains impacted above criteria for metals. As stated in the ROD, there are background concentrations for some metals which exceed criteria, and the landfill may add to these impacts. The presence of elevated metals and other inorganics is addressed by the remedy
, via groundwater use restrictions in the CEA. The Long-Term Monitoring Plan should be reviewed to ensure that the data being collected are sufficient to determine whether aquifer restoration (i.e., contaminant concentrations at or below NJGWQS or MCLs) can be achieved. If NJGWQS or MCLs cannot be attained after implementation of the groundwater remedy, then the ROD calls for issuance of Technical Impacticability (TI) waivers, through an ESD.
Leachate and landfill gas monitoring has continued under the landfill closure plan.
Site Inspection
. A site inspection related to the five-year review was conducted on December 22,2010. Those in attendance included: Douglas Tomchuk (EPA-RPM); Lora Smith (EPA-Risk Assessor); Mindy Pensak (EPA-Ecological Risk Assessor), Ed Modica (EPA-Hydro geologist) and Glenn Savary (NJDEP Project Manager).
Activities included a walk-though of the bioreactor piping system, and a drive through of the landfill. A visual inspection of the residential water supply wells was also conducted.
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Interviews
EPA Region 2 staff met with the NJDEP project manager, Glenn Savary and representatives of the L&D Company (Rob Greenwald, Peter Rich and Roy Wagner of GeoTrans, and Carl Januszkiewicz of Waste Management) during the site visit. No formal interviews were conducted for this review.
VII. Remedy Assessment
Question A: Is the remedy functioning as intended by the decision documents?
All components of the groundwater remedy for the L&D Landfill Superfund Site have been installed, are operational, and are functioning as intended by the decision documents.
According to the 2004 ROD, the major components of the remedy include construction of a groundwater extraction system, construction ofenhanced aerobic treatment, long-term monitoring in the central and flank areas of the landfill, maintenance of existing cover, continued landfill leachate and gas monitoring, collection and disposal, maintenance of site security, and decommissioning of residential water-supply wells (and public water line extension) downgradient ofthe landfill.
The Groundwater ExtractionlRecirculation component of the remedy is intended to provide hydraulic containment ofdissolved phase VOCs in the Middle Wenonah aquifer ofthe Central Area (Cell 9) of the landfill, an area where the greatest impact to groundwater was observed. The system also allows extracted groundwater and other landfill leachate to recharge the cell. Construction of the system began in July of2006 and was put into operation by late February 2007. Based on performance data, the extraction system is performing as designed, effectively containing dissolved phase VOCs and preventing downgradient migration.
Based on process performance data, the extraction system is performing as designed, effectively containing dissolved phase VOCs and preventing downgradient migration.
The Enhanced Aerobic Treatment component of the remedy included air injection and groundwater/leachate recirculation to stimulate biodegradation of waste in the source area and enhance contaminant mass reduction in the landfill. The construction of the air-recirculation system began July 2006 and was operated between Dec 2007 and April 2008. While in operation, this system functioned as intended as VOC concentrations were reduced, generally on the order of 90 to 100%. It was determined that continuing operation of the aeration system would provide limited additional benefit when compared with the cost of system operation and according to the 2011 Remedial Action Report, no further operation of the air recirculation system is planned. Water quality data from Process Monitoring indicate that Enhanced Aerobic Treatment worked as designed. Evaluation of influent from recovery wells shows that VOC concentrations declined during operation. '
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Air quality data from Process Monitoring indicate that Enhanced Aerobic Treatment is having its intended effect on contaminant mass. Following a test period in November 2007, the air recirculation system was brought on-line and was operated for 3.5 months beginning December 10, 2007. On April 2, 2008, the air recirculation was discontinued due to subsurface combustion ~fwaste near air injection well AI-2S. Summa canister results from extended air system testing (Fall of2010) indicated that the VOC contaminant mass remaining in Cell 9 was reduced. Due to substantial reduction in vapor concentrations in Cell 9 for VOC constituents in groundwater, further operation of the air system was determined to have had little added benefit given the cost of operating the air system.
The Long-Term Groundwater Monitoring Program was initiated in May 2006. Monitoring wells are screened in the MoUnt Laurel/Cape May Sands (MLCMS), Middle Wenonah, and Englishtown aquifers and are sampled at different frequencies, according to the aquifer. In general, results from most recent groundwater sampling (November 2010) show that monitoring wells in Flank Areas show VOC concentrations that are substantially lower than the center. There are some exceedances of vinyl chloride, chlorobenzene, and benzene reported in wells in the MLCMS and Middle Wenonah aquifers in the Flank Areas, although still located on the landfill property. There were no exceedances reported for wells screened in the Englishtown aquifer.
NJDEP issued a Classification Exemption Area in 2008 to restrict groundwater use in the vicinity of the site until groundwater standards are achieved. A CEA was necessary to manage elevated metal concentrations. Groundwater remains impacted above criteria for metals. As stated in the ROD, there are background metals concentrations exceeding criteria for some metals, and the landfill may add to these impacts. The presence of elevated metals and other inorganics is addressed by the remedy via water use restrictions. The CEA applies vertically to . the shallowest aquifers (the MLCMS and the Wenonah), ensuring that uses of the aquifer are restricted until groundwater standards are achieved. A well survey was performed for other wells between the landfill and Rancocas Creek. It was found that all properties were either connecting to public supply or have wells screened in the uncontaminated Englishtown aquifer for potable supply and confirmed that any existing wells screened in shallower aquifers are not used for potable purposes. Continued operation of the groundwater extraction system and process monitoring in conjunction with the CEA ensures protectiveness of human health and the environmerit.
.. Groundwater remains impacted above criteria for metals. As stated in the ROD, there are· . background concentrations for some metals which exceed criteria, and the landfill may add to
these impacts. The presence of elevated metals and other inorganics is addressed by the remedy via groundwater use restrictions in the CEA. The Long-Term Monitoring Plan should be reviewed to ensure that the data being collected are sufficient to determine whether aquifer restoration (i.e., contaminant concentrations at or below NJGWQS or MCLs) can be achieved. If NJGWQS or MCLs cannot be attained after implementation of the groundwater remedy, then the ROD calls for issuance of TI waivers, through an ESD.
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According to the September 2009 Explanation of Significant Differences, the residential watersupply component of the remedy was modified, such that residents on Hand Lane and the western part of Rabbit Run were to be provided new residential water supply by the installation of wells at remaining properties not owned by Burlington County. The new water supply wells are in lieu of the public water line extension described in the 2004 ROD. Four wells were installed, one at Hand Lane and three on Rabbit Run. Installation of the last well was completed in July 2010. The wells were double-cased and screened in the Englishtown Aquifer, which is known not to be impacted by the landfill. Two residential wells on Hand Lane and Rabbit Run were identified for decommissioning. The wells were properly abandoned and sealed in place in June of201O. The residential well component of the remedy has been completed and is functioning as intended.
Other structural components of the remedy appear to be regularly maintained and functional. Although some subsidence was noted on inspection, the condition of the landfill cover appeared to be in good repair and well maintained. The gas monitoring and leachate collection systems are functioning and are well maintained. The fence that encloses the landfill is in good repair; if any fence sections are occasionally breached or vandalized, they are promptly repaired.
Every effort should be made to minimize trespassing for the purpose of preserving the integrity of the cover system. When trespassers or vandals do come on the site, L&D Company should continue to conduct any necessary repairs in a timely manner. It should be noted that the following activities should continue in accordance the existing plans:
• landfill leachate collection, monitoring and disposal; • groundwater extraction with a portion ofextracted water diverted to recharge Cell 9; •. process monitoring at monthly frequency; • implementing L TM program at current frequency; and, • monitoring contamination levels in extraction well RW-3 to determine whether VOC
concentrations become low enough to consider the well for shutdown.
Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives used at the time of remedy selection still valid?
There have been no physical changes to the site that would adversely affect the protectiveness of the remedy.
Land use assumptions, exposure assumptions and pathways, cleanup levels and remedial action objectives (RAOs) considered in the decision documents remain valid. Although specific parameters have changed since the time the risk assessment was completed, the process that was used remains valid.
All groundwater monitoring data are compared to NJDEP's Ground WaterQuality Standards (NJ.A.C.7:9C). While some NJGWQS have been revised since the time of the hUman health risk assessment and the ROD, the selected remedy remains protective of human health.
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The selected remedy was necessary in order to attain the RAOs. The groundwater extraction system is reducing the mass, toxicity, and/or mobility of potentially hazardous constituents in Cell 9 and is expected to aid in achieving remediation goals established for groundwater in the MLCMS and Middle Wenonah aquifers. The landfill cover, fence, and continued maintenance of these barriers prevent direct contact with landfill contents and control surface water runoff and erosion. Decommissioning of residential wells and restricting installation of new wells prevents human consumption of groundwater from contaminated aquifers in the area. The groundwater ~d leachate monitoring systems reduce leaching of constituents to groundwater and control iandfill gas migration.
Soil vapor intrusion (VI) is evaluated when soils and/or groundwater are known or suspected to 'contain VOCs. A January 2004 evaluation of the potential for VI in residences downgradient of the landfill found the vapor intrusion pathway was incomplete. This was based on the finding of a low level of one VOC in the shallow groundwater in the proximity of downgradient residences (as compared with the November 2002 OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils). The LTM data supports the determination that only low levels ofVOCs are found downgradient of the landfill in the shallow aquifers, and that concentrations in those wells are decreasing for most VOCs. Therefore, the vapor intrusion pathway is likely to remain incomplete. No specific monitoring for soil vapor intrusion is necessary.
Although the ecological risk assessment screening values used to support the 2004 ROD may not necessarily reflect the current values, the exposure assumptions remain appropriate and thus the remedy remains protective of ecological resources. The terrestrial exposure pathway has been addressed by containing contaminated soil within a secure covered landfill. However, it was noted during the site visit that in some areas, the integrity of the cap may have been ,compromised by installing the groundwater treatment system. Continued cap maintenance
. should continue to ensure the cap integrity remains, so as to minimize ecological risk. Groundwater treatment is noted to have minimal drawdown in the wetland areas. Drawdown in the wetland area should be considered and annually monitored to minimize potential ecological impacts. No evidence of adverse risk in either the Smithville Canal or Rancocas Creek was found to be associated with the landfill during the RIfFS, and no data collected since then would suggest that this would be of concern.
Question C: Has any other information come to light that could call into question the protectiveness of the remedy?
No human health or ecological risks have been identified, and no weather-related events have affected the protectiveness of the remedy. No other information has come to light that could call . into question the protectiveness of the remedy.
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Technical Assessment Summary
According to the data reviewed and the site inspection, the remedy is functioning as intended by the ROD. There have been no changes in the physical conditions of the site that would affect the protectiveness of the remedy. For residences downgradient of the landfill that remain~\the installation of wells, screened in the Englishtown aquifer, along with establish!nent ofthe, ", Classification"ExS,eption,ruefensures that usage of the shallow aquifers is~~estriCted ~r:til", " groundwatef..'Stan.dards are~achi~ved. __ ..... ,.'. >. ,'- " '.~ _ ~"" .......<"
..~.
VIII. Recommendations and Follow-Up Actions
This report does not identify any issues or recommend any action at this site needed to protect public health and/or the environment that is not addressed by the remedy selected in the site decision documents as routinely operated, modified, maintained and, adjusted over time . .It should be noted that the following activities should continue in accordance with the existing 'plans:
• landfill leachate collection, monitoring and disposal; • groundwater extraction with a portion of extracted water diverted to recharge Cell 9; • process monitoring at a monthly frequency; • implementing the L TM program at the current frequency; and, • monitoring contamination lev~ls in extraction well RW-3 to determine whether VOC
concentrations become low enough to consider the well for shutdown.
The Long-Term Monitoring Plan should be reviewed to ensure that the data being collected are sufficient to determine whether aquifer restoration (i.e., contaminant concentrations at or below NJGWQS or MCLs) can be achieved. IfNJGWQS or MCLs cannot be attained after implementation of the groundwater remedy, then the ROD calls for issuance ofT! waivers, through an ESD.
IX. Protectiveness Statement
Because the remedial actions at the L&D Company Site are protective, the site is protective of human health and the environment. The landfill is capped and fenced, hydraulic containment has been established, and new water supply wells installed and screened in an aquifer not affected by the site for the remaining downgradient residences. Institutional controls are in place in the form of the approved landfill closure plan and the groundwater Classification Exception Area established by NJDEP. These controls will need to remain in place until contaminant concentrations in groundwater meet the appropriate criteria.
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X. Next Review
The second five-year review for the L&D Company Site should be completed before July 2016, ears from this report's approval date.
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...J~ It; 2-(1) Date
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Table 1 Chronology of Site Events
Event Date
Sand and gravel pit operations at the site Early 1940s - 1968
George Pettinos began demolition debris disposal 1962
The landfill began accepting industrial and cOmIi1ercial solid waste and sewage sludge 1968
The Landfill and Development Company acquired the property 1971
The L&D Landfill Site was added to the National Priorities List (NPL) 1983
NJDEP provided funds to conduct an RIIFS May 30, 1986
Permitted capacity reached - stopped accepting waste December 31, 1986
L&D entered into an Administrative Order on Consent with NJDEP 1988
Constructed closure systems approved May 24, 1995
Proposed Plan issued May 20, 2004
Record of Decision issued Sept. 30, 2004
Remedial Action Work Plan Approved June 30, 2006
On-site construction started July 17,2006
Classification Exception Area designated by NJDEP May 23, 2008
Explanation of Significant Differences for residential water supply issued September 3,2009
Remedial Action Work Plan Addendum (for water supply wells) approved July 29, 2009
Water supply wells installed Feb - August 2010
Preliminary Close-Out Report Issued by EPA Sept. 27, 2010
Site visit for Five-Year Review December 22, 2010
Remedial Action Report issued January 31, 2011
Remedial Action Report approved by NJDEP May 25,2011
Concurrence on Remedial Action Report approval by EPA June 9, 2011
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i! •
Table 2
Documents Reviewed:
Revised Ecological Risk Assessment Report (April 2000)
September 2004 Record of Decision,
Superfund Preliminary Close-Out Report dated September 2010
Remedial Action Report L&D Landfill, Mount Holly, January 31, 2011, prepared for L&D Co., Inc. by GeoTrans, Inc.
See water/air quality data tables: -Water Process Monitoring Results, Tables C-1 to C-4 -LTM Results, November 2010 Sampling Event, Tables D-1 to D-4 -Historical Sampling Results for Selected VOCs, Table D-5 -Air System Data, Summa Cannister Results, Tables E-6 to E-10
Letter approving the Remedial Action Report, from Glenn Savary,_ NJDEP to Mark Devine of Waste Management, dated May 25,2011
Letter concurring with NJDEP approval of Remedial Action Report, from Carole Petersen, EPA to Len Romino, NJDEP, dated June 9, 2011
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Table 3:
Cleanup Goals - For L& D Site contaminants in groundwater.
Contaminant Cleanup Goal (ug/l)
1,2-Dichloroethane 2
2-Butanone 300
4-Methyl-2-Pentanone
400
Acetone 700
Benzene 1
Cis-I,2dichloroethene
10
Methylene Chloride 2
Toluene 1000
Vinyl Chloride 2
24
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~ o N o <0 Z
90
60
30
~
-' III :::; 0
...: w w .':::. -30 z 0
« '" > -60 w -' w
-90
-120
-150
WEST C
:;:
f
SYSTr.>~!:'!:-~---;-:-;,;-IT.O.C. M..58
UPPER
. lvilODLE
LOWER
~
WENONAH
WENONAH
MARSHALLTOWN
ENGLISHTOWN
LEGEND
LDE-l -WELL OR PIEZOMETER IDENTIFICATIONI'"' ~. -TOP OF CAS'" mVAnoN (FEET)
_--'+====:::-- TOP OF CASING
EXISTING GROUND
~%E~FL~~fE}hINfRVAL W.L. 38.4r--BOTTOM OF SCREEN INTERVAL
i__-----BOTTOM OF WELL OR PIEZOMETER
1. FOR CROSS-SECTION LOCATIONS SEE FIGURE 2.
2. WATER LEVELS FOR SECTION C-C' AND F -F" WERE MEASURED ON 14 JUNE 1995.
Figu NOTE: Based an Drawing in Phase II RI Adendum (GeaSyntec, 1995).
Figure 1
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" QUADRANGLEr ,/1 .... LOCATIONS
SOURCE: U.S.G.S QUADRANGLES, MOUNT HOLLY, NJ, 1967 (PHOTOREVISED 1981 ) & PEMBERTON. NJ, 1957 (PHOTOREVISED 1981 ). ,.._________________....
o 2000 4000
Figure 2SCALE IN FEET
~ 1 A.
EXTENT OF LEACHATE COlLECnON SYSTEM AND
WlEHll SWALES (USUAlLY DRY) INTERMEDIATE LINER FENCE LINE MONITORING WELL SLOPE ASSOCIATED WITH •
RESIDENCES THAT RECEIVED - THE LANDFILL 181 NEW SUPPLY WELL AS .J.IIIi::lIIl. MLCMS AQUIFER PART OF REMEDY [UIIHCIe) MIDDLE WENONAH AQUIFER GROUNDWATER EXTRACTION ~ ENGLISHTOWN AQUIFER WELLS - CENTRAl AREAA
REMEDY0 LEACHATE COLlECTION MANHOLE D CEA EXTENT
~ LANDFill CELLS
PREVIOUSLY PLANNED WATERLINE EXTENSION
SECTION
o 1000 2000 I~~~~~I~~~~I
SCALE IN FEET
Figure 3
