five year reviewfive-year review report third five-year review report for south andover site...

30
--_._------- Five-Year Review Report Third Five-Year Review Report for South Andover Site Andover, Anoka County, Minnesota June 2011 Prepared by: United States Environmental Protection Agency Region 5 Chicago, Illinois Approved by: Date: 7 - I J Richard C. Karl, Director Superfund Division U.S. EPA, Region 5

Upload: others

Post on 26-Jan-2021

1 views

Category:

Documents


0 download

TRANSCRIPT

  • --_._-------

    Five-Year Review Report

    Third Five-Year Review Report

    for

    South Andover Site

    Andover, Anoka County, Minnesota

    June 2011

    Prepared by: United States Environmental Protection Agency

    Region 5

    Chicago, Illinois

    Approved by: Date:

    7 - I J

    Richard C. Karl, Director Superfund Division U.S. EPA, Region 5

  • [This page intentionally left blank.]

  • Table of Contents

    List of Acronyms .............................................................................................................................. v

    Executive Summary ...................................................................................................................... vii

    Five-Year Review Summary Form ................................................................................................ ix

    I. Introduction ........................................................................................................................ 1

    II. Site Chronology .................................................................................................................. 2

    III. Background ........................................................................................................................ 2 Physical Characteristics Land and Resource Use History of Contamination Initial Response Basis for Taking Action

    IV. Remedial Action ................................................................................................................. 5 Remedy Selected Remedy Implemented Institutional Controls Monitoring

    V. Progress Since the Last Five-Year Review .................................................................... 11

    VI. Five-Year Review Process ............................................................................................... 12 Administrative Components Community Notification and Involvement Document Review Data Review Site Inspection

    VII. Technical Assessment ...................................................................................................... 13

    VIII. Issues ................................................................................................................................. 13

    IX. Recommendations and Follow-Up Actions .................................................................... 13

    X. Protectiveness Statement ................................................................................................. 14

    XI. Next Review ...................................................................................................................... 14

    Attachment ................................................................................................................................... 15 Attachment A. Documents Consulted

    Figures ........................................................................................................................................... 17 Figure 1. Site boundaries and reported waste disposal activities, South Andover Site Figure 2. Locations of monitoring wells Figure 3. Approximate Site boundary shown on a recent aerial photo of the area. Figure 4. Location of plume within Andover city limits.

    South Andover Site--Five-Year Review Report -iii- June 2011

  • [This page intentionally left blank.]

  • ARARs

    bgs

    cPAHs

    CFR

    CERCLA

    1,2-DCA cis-l,2-DCE CRA FIT FS HRL IC MCL MPCA msl MW NCP NPL OU PAH PCB PCE PRPs RAL RA RD RI ROD SAAG SMCL SOW SY~C

    1,1,2-TCA TCE TSCA USEPA UUIUE VIC VOC

    List of Acronyms

    applicable or relevant and appropriate requirements below ground surface carcinogenic polynuclear aromatic hydrocarbons Code of Federal Regulations Comprehensive Environmental Response, Compensation, and Liability

    Act 1 ,2-dichloroethane cis-l,2-dichloroethene Conestoga-Rovers & Associates Field Investigation Team feasibility study health risk limit institutional controls maximum contaminant level Minnesota Pollution Control Agency mean sea level monitoring well National Contingency Plan National Priorities List operable unit polynuclear aromatic hydrocarbons polychlorinated biphenyl tetrachloroethene (perchloroethylene) potentially responsible parties recommended allowable limit remedial action remedial design remedial investigation Record of Decision South Andover Administrative Group secondary maximum contaminant level statement of work semi-volatile organic compound 1,1,2-trichloroethane trichloroethene Toxic Substances Control Act United States Environmental Protection Agency unlimited use or unrestricted exposure Voluntary Investigation and Cleanup volatile organic compound

    South Andover Site--Five-Year Review Report -v- June 2011

  • [This page intentionally left blank.]

  • Executive Summary

    Record of Decision (ROD) Amendments were issued in June 1992 for operable unit (OU) 1, which addressed contaminated groundwater, and in May 1994 for OU 2, which addressed contaminated soils. These followed the ROD issued in March 1988 for au 1 and the ROD issued in December 1991 for au 2. The groundwater remedy required: short-term monitoring of the groundwater (for approximately five years); immediate resampling if an action level were exceeded; abandonment of wells no longer being monitored; and further monitoring if determined to be necessary. The soil remedy required: excavation and off-site transportation for thermal treatment of soil predominately contaminated with carcinogenic polynuclear aromatic hydrocarbons (cPAH); excavation and off-site transportation of soils contaminated with polychlorinated biphenyls (PCBs), cPAHs, lead, and antimony for disposal; sampling and removal of drums remaining on the Site; and groundwater monitoring for three years after all excavation was finished. The Site achieved construction completion with the signing of the Preliminary Close Out Report on November I, 1994. The trigger for this review was the signing of the second five-year review report in September 2006.

    The assessment of this review is that the remedy was constructed and was monitored in accordance with the two ROD Amendments. The groundwater monitoring periods specified in the RODs and ROD Amendments were insufficient and no institutional controls were required. Groundwater monitoring greater than that required in the decision documents has been performed over the last several years to track the contaminated plume. The groundwater sampling data do not show an indoor air vapor intrusion pathway present despite volatile organic compounds (VOCs) present in the groundwater. The restrictions on installing wells within the City of Andover prevent future exposure to the small contaminated groundwater plume that still exists. For the soil, OU2, the remedy is considered protective in both the short-term and the long-term because there is no evidence of current or future exposure. For the groundwater, OU I, the remedy is considered protective in the short-term because there is no evidence of current exposure. Long-term protectiveness of the groundwater will be achieved when the groundwater reaches cleanup levels. For the entire site, the remedy is considered protective in the short-term because there is no evidence of current exposure. Site-wide long-term protectiveness will be achieved when the groundwater reaches cleanup levels.

    South Andover Site--Five-Year Review Report -vii- June 2011

  • [This page intentionally left blank.]

  • F'IVe-Year ReVlew summary Form SITE IDENTIFICATION

    Site Name (from CERCLlS): South Andover Site

    EPA ID (from CERCLlS): MND980609614

    Region: 5 I State: MN I City/County: Andover, Anoka County SITE STATUS

    NPL status: x Final Deleted Other (specify) Partially Deleted (OU 2--soil}

    Remediation status (choose all that apply): Under construction x Operating Complete

    Multiple OUs?* x Yes No I Construction completion date: 11/01/94 Has site been put into reuse? JL Yes No

    REVIEW STATUS

    Lead Agency: x EPA State Tribe Other Federal Agency

    Author name: Bernard J. Schorle

    Author title: Remedial Project Manager I Author affiliation: USEPA, Region 5 Review period:** 10106 to 5111

    Date(s) of site inspection: May 24, 2011

    Type of review: -.:i. Post-SARA - Pre-SARA Non-NPL remedial action site NPL State/Tribe-lead - -Regional discretion NPL-removalonly

    Review number: I (first) 2 (second) x 3 (third) Other (specify)

    Triggering action: Actual RA on-site construction at OU # Actual RA start at OU #- -=Construction completion JL Previo.us five-year review report Other (specify)

    Triggering action date (from CERCLlS): 9129106 Due date: 9/29/11 *--"OU" refers to operable UOlt

    **--Review period should correspond to the actual start and end dates of the five-year review in CERCLIS

    Issues:

    VOC concentrations in the groundwater remain at levels in excess of MCLs.

    Recommendations and Follow-up Actions:

    Continue the groundwater monitoring. This should be done about once every 30 months to monitor the

    concentrations of vinyl chloride and other VOCs.

    Protectiveness Statement(s):

    For the soil, OU2. the remedy is considered protective in both the short-term and the long-term because there is no

    evidence of current or future exposure. For the groundwater, OU 1, the remedy is considered protective in the short

    term because there is no evidence of current exposure. Long-term protectiveness of the groundwater will be

    achieved when the groundwater reaches cleanup levels. For the entire site, the remedy is considered protective in the

    short-term because there is no evidence of current exposure. Site-wide long-term protectiveness will be achieved

    when the groundwater reaches cleanup levels.

    South Andover Site--Five-Year Review Report -IX- June2011

  • [This page intentionally left blank.]

  • South Andover Site

    Andover, Anoka County, Minnesota

    Third Five-Year Review Report

    I. Introduction

    The purpose of a five-year review is to detennine whether the remedy at a site is protective of human health and the environment. The methods, findings, and conclusions of the review are documented in a five-year review report. In addition, the five-year review report identifies issues found during the review, if any, and provides recommendations to address them.

    The U.S. Environmental Protection Agency (USEPA) is preparing this five-year review report pursuant to Section 121 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (42 U.S.C. § 9621) and the National Contingency Plan (NCP) (40 Code of Federal Regulations (CFR) Part 300).

    CERCLA §121 states:

    If the President selects a remedial action that results in any hazardous substances, pollutants, or contaminants remaining at the site, the President shall review such remedial action no less often than each 5 years after the initiation of such remedial action to assure that human health and the environment are being protected by the remedial action being implemented. In addition, if upon such review it is the judgment of the President that action is appropriate at such site in accordance with section 104 or 106, the President shall take or require such action. The President shall report to the Congress a list of facilities for which such review is required, the results of all such reviews, and any actions taken as a result of such reviews.

    USEPA interpreted this requirement further in the NCP; 40 CFR §300.430(f)(4)(ii) states:

    If a remedial action is selected that results in hazardous substances, pollutants, or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure, the lead agency shall review such action no less often than every five years after the initiation of the selected remedial action.

    USEP A Region 5 has conducted this five-year review of the remedies implemented at the South Andover Site (Site) in Andover (Anoka County), Minnesota, a National Priorities List (NPL) site. This review was conducted for the entire Site by the remedial project manager (RPM) for the period from October 2006 through May 2011. This report documents the results of the reVlew.

    This is the third tive-year review for the Site. The triggering action for this statutory review is the signature date of the second five-year review report on September 29,2006. 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 or unrestricted exposure.

    South Andover Site--Five-Year Review Report -1- June 2011

  • II. Site Chronology

    Event Date

    Salvage operations and waste disposal 1954 - 1981

    Two fires involving tires 1988 - 1989

    Proposed for placement on the National Priorities List (NPL) 12/30/82

    Final on NPL 9l 08/83

    Remedial investigation (Rt) report, operable unit (OU) I, groundwater 1/29/88

    Feasibility study (FS) report, OU 1 1/29/88

    Record of Decision, OU 1 3/30/88

    Rt report, OU 2, soil July 1991

    FS report, OU 2 October 1991

    ROD, OU 2 12/24/91

    Design investigation report, OU 1 February 1992

    ROD Amendment, OU 1 6/09/92

    Consent Decree with South Andover Administrative Group (SAAG), lodged 4/30/93 entered 8/27/93

    Focused FS, OU 2 March 1994

    ROD Amendment, OU 2 5/31/94

    Preliminary Close Out Report (construction completion under CERCLA) 11/1/94

    Remedial action report, OU 2 December 1994

    Notice of intent to delete OU 2 from the N PL 9/15/98

    Notice of deletion of OU 2 from the NPL 10/28/98

    First five-year review report 9/28/01

    Technical correction of partial deletion ofOU 2 from the NPL 8/18/06

    Second five-year review report 9/29/06

    Site inspection for third five-year review 5/24/ II

    III. Background

    Physical Characteristics

    The Site is located in Andover. Minnesota, near its southern limits, approximately 16 miles north-northwest of Minneapolis and 3 miles northeast of the City of Anoka. The site is situated at 450 16' N Latitude, and 93 0 12' W Longitude, in the south half of Section 34, Township 32 North, Range 24 West. The City of Andover was fonnerly known as Grow Township.

    Land and Resource Use

    At the time of the remedial investigation, the Site was made up of several privately owned parcels of land that totaled approximately 50 acres. Figure I shows the Site boundaries and the names of some of the operators that were on the Site. Bunker Lake Boulevard defines the northern extent of the irregularly shaped Site and Jay Street is located approximately 300 feet east of the Site. Figure 2 shows the location of the Site in relation to these two streets and also shows the locations of some of the monitoring wells. Figure 3 shows the approximate location of the Site on a recent aerial photo of the area.

    South Andover Site--Five-Year Review Report -2- June201 I

  • For many years this area was sparsely populated. However, residential development was initiated 1/4 mile north of the Site in the early 1970s, and continued development has occurred to the east, north, and south. Small businesses and new residential developments are now common in the vicinity of and on the Site. There are several businesses located on the Site, including a department store, a grocery store, a chain drug store, and a small mall.

    The Waste Disposal Engineering Landtill is located about 3,000 feet northeast of the Site. This landtill, which formerly accepted hazardous waste, is a National Priorities List site.

    There are several small recreational lakes in the area. Crooked Lake is 1 mile west of the Site and Bunker Lake is 1 1/4 miles to the east. The Site is generally located within the Coon Creek watershed, which supports an oak savannah plant community.

    History of Contamination

    At and prior to the listing of the Site on the National Priorities List, auto salvage operations were conducted at the Site. Additionally, storage, disposal, and incineration of ink; ink and paint sludge; adhesives; chlorinated and non-chlorinated solvents; and other wastes occurred at var'ious locations across the Site. Solvent recovery and the storage of transformers and salvaged electrical equipment were also reported. Former drum storage and chemical waste disposal areas were partially obscured by more than 3 million waste tires.

    Industrial waste handling operations began at the Site during the mid 1950s. More than 1,000 drums of waste were stored on several contiguous parcels owned by Cecil Heidelberger, William Batson, David and Shirley Heidelberger, Charles Mistelske, and Cyril Link. Trenching, depression tilling in wetlands, dumping and burning of wastes, open pit burning, and smelting operations have been reported on several of the parcels.

    Two tire tires occurred at the Site. The tirst occurred during July 1988 near the northeastern portion of the Cecil Heidelberger property. The fire was confined to this general area where small piles of tires and rubber chips were located and was extinguished with water. A second, much larger tire tire occurred at the Site in February 1989. Information from the Minnesota Pollution Control Agency (MPCA) indicates that this fire involved three to five acres and approximately 300,000 tires located near the southeastern portion of the Cecil Heidelberger property. A tire break was established around the tire area and the tire was smothered with sand after burning two to three days. Some empty drums and drums containing industrial chemical wastes were involved in the fire. These drums were later removed from the Site under MPCA's emergency removal program.

    Initial Response

    Several early investigations were performed at the Site. An initial appraisal was performed by Residual Management Technologies (RMT) and PEDCo Environmental in 1979 at the request of USEPA. A follow-up investigation by RMT/PEDCo in 1981 included the installation of 22 monitoring wells. Ecology & Environment, Inc. (E&E) installed 26 additional wells and 22 piezometers in 1981 as part of an expanded Field Investigation Team (FIT) groundwater investigation.

    An initial RI, completed in January 1988, was performed at the Site to characterize the nature and extent of contamination. Soil investigations were limited by the presence of the large volume of tires piled on the Site and piles ofjunked automobiles at various auto salvage yards on the Site, so this study dealt mainly with the groundwater, OU 1. An FS was performed in conjunction

    South Andover Site--Five-Year Review Report -3- June 2011

  • with this RI and the report for the FS was issued in January 1988. Following the removal of the tires, a second RI was performed that focused on the potential soil and surface water contamination at the Site, OU 2. The report for this RI was issued in July 1991 and the FS report for OU 2 was issued in October 1991. A design investigation took place following the RI for OU 1 to determine the current groundwater quality within the surficial aquifer system and to provide data that would be useful for determining whether the remedy that had been selected for OU 1 should be implemented or revised. The report for the design investigation was issued in February 1992 (incorrectly stated as February 1991 on the title page of the report). When it was determined through additional sampling that the amount of soil unacceptably contaminated by carcinogenic polynuclear aromatic hydrocarbons (cPAHs) (the ROD clean-up level was 4 ppm for PAHs) was significantly less than what had been estimated previously, a focused FS was conducted to determine the most effective treatment technology for the cPAH-contaminated soils. The report for this study was issued in March 1994.

    The first two RIs showed the presence of three major hydro-stratigraphic units within the unconsolidated sediments: an upper sand aquifer which ranges from 23 to 40 feet thick, an intermediate till and lacustrine aquitard that is 47 to 65 feet thick, and a lower sand aquifer. These unconsolidated sediment deposits are underlain by a sandstone bedrock aquifer. Major water users in the Coon Creek watershed obtain potable water supplies from the bedrock aquifer. The lateral flow in the surficial aquifer was found to radiate in a generally westwardly direction from the eastern portion of the Site. Water level measurements in the well nests indicated a dominant downward component of flow in both the surficial aquifer and the middle aquitard. The potentiometric surface of the lower sand aquifer indicated lateral flow southwest across the Site.

    During the initial RI, elevated levels of a number of organic and inorganic compounds were detected in shallow monitoring wells on the Site. A summary of the chemicals detected at the Site is given in Table 6-1 of the 1988 RI report. Only one contaminant was detected in samples from the lower sand aquifer, and it was only detected in one well, which contained 97 ppb methylene chloride. The methylene chloride may be a lab contaminant as opposed to actually being present in the well. Residential well sampling by Anoka County and the MPCA indicated that one residential well on-site, which was drawing from the surticial aquifer, was found to be contaminated. This well was ordered to be abandoned by the MPCA.

    The 1988 ROD said that the contaminants in the groundwater were found in zones of discrete contaminated areas rather than in a continuous plume and that this was indicative of the multiple waste handling and disposal operations which occurred on the Site. The 1992 ROD Amendment said, " In conclusion, the results of the Design Investigation indicate that a discrete groundwater plume does not exist at the Site. Rather, the groundwater situation is best characterized by random detections of compounds below background and regulatory standards." Later, it was found that there was a plume extending otTthe Site.

    The following types of compounds were detected in soil, sediment, surface water, or groundwater at the Site: halogenated volatile organic compounds (vinyl chloride, methylene chloride, chloroform, 1,1, I-trichoroethane, trichloroethene, tetrachloroethene); nonhalogenated volatile organics (acetone, carbon disulfide, 2-butanone, 4-methyl-2-pentanone, 2-hexanone, toluene, ethyl benzene, styrene, xylenes); halogenated semivolatile organics (PCBs, some pesticides, chlorinated phenols); nonhalogenated semivolatile organics (PAHs, phthalates, phenols); and inorganic compounds (metals, cyanide).

    The horizontal extent of soil contamination was spatially discontinuous and heterogeneous, which is characteristic of a "hot spot" distribution. Vertical contamination was generally limited

    South Andover Site--Five-Year Review Report -4- June2011

  • to surface soils at a depth of 6 feet or less. Volatile organic compound contamination extended to the water table. Low level volatile organic compound contamination existed in isolated areas on-site in soils and groundwater in both the upper and lower aquifer systems. Contamination by P AHs, semivolatile organic compounds, occurred in the soil. Both soil and groundwater were contaminated with bis(2-ethylhexyl)phthalate. Low concentrations of PCBs were found in isolated areas in the surface soil. The highest detected PCB concentration was 15 ppm and occurred 0 to 6 inches below the ground surface. Inorganic contamination by antimony and lead was associated with some areas of till, at depths of 6 feet or less. Groundwater contained elevated levels of arsenic. The observed direction of groundwater flow suggested an on-site arsenic source. It is not known if the arsenic-containing soil on-site was the only source impacting the groundwater. The semi volatile P AH, PCB, pesticide, and inorganic contaminants present at the Site demonstrate relatively low potential for subsurface mobility. Some volatile organic compounds demonstrated moderate to high mobility.

    Basis For Taking Action

    The contaminated surficial aquifer contained several contaminants at concentrations which exceeded maximum contaminant levels (MCLs) set by the Safe Drinking Water Act and posed excess lifetime cancer risks that were greater than 1 x 1 0-6• The groundwater did not pose an imminent risk to the population because the upper aquifer was not being used as a source of drinking water on or near the Site. However, because there was a downward gradient through the aquitard separating the upper and lower sand aquifers, the upper sand aquifer was a possible source of contamination to the lower sand aquifer which served as a regional drinking water source. There was a potential for an increase in the excess lifetime cancer risk to a value greater than 1 x 1 0-6 if wells were set in the upper aquifer as a result of future development of the Site or if the lower aquifer became contaminated. In addition to the cancer risk, use of the contaminated groundwater would exceed the reference dose for bis(2-ethylhexyl) phthalate and acetone.

    In the baseline risk assessment for the Site, the evaluation of metals and detected organic chemicals led to an estimated excess lifetime cancer risk from groundwater of 5x 1 0-4 for the upper sand aquifer and 2x 10-4 for the lower sand aquifer. A majority of the risks were due to arsenic. Total population cancer risk was mainly due to the risk from groundwater. When this risk was added to the risk from soil for residents, the total estimated site-related excess cancer risk ranged from 5x 1 0-4 to 7x 1 0-4. The hazard index is the risk of noncancer effects from site-related chemicals. It is the ratio of calculated intake to acceptable intake. When the hazard index is less than or equal to 1, noncancer health effects are considered to be unlikely. For the groundwater, a couple of detected contaminants contributed a hazard index greater than 1 under conservative conditions. For pathways other than groundwater in both current and hypothetical future scenarios, only one calculated hazard index exceeded 1. The exceedance was for the hypothetical future child resident at one location, where the subchronic hazard index was 3 due to the presence of antimony. At five surface soil sample locations, lead levels exceeded values that might produce blood levels that exceed 10 to 15 micrograms per deciliter (flgldL), the acceptable level established by USEPA at the time. Lead in groundwater did not exceed the USEPA exposure range.

    IV. Remedial Action

    Remedy Selected

    USEPA issued a Record of Decision (ROD) for OU 1 on March 30, 1988 and issued a second ROD, for OU 2, on December 24,1991. While the soil investigation was ongoing, an additional investigation of the groundwater was conducted because of questions raised about the remedy

    South Andover Site--Five-Year Review Report -5- June 2011

  • that had been selected for the groundwater. The results of this additional investigation lead to USEPA issuing a ROD Amendment for OU 1 on June 9,1992. In 1993, USEPA negotiated an agreement with some of the potentially responsible parties for the Site, the South Andover Administrative Group (SAAG), to implement the remedy. This resulted in a consent decree that was entered by the court on August 27, 1993. The SAAG retained Conestoga-Rovers & Associates (CRA) as a consultant for the remedial design and remedial action program. In the course of the design work, CRA determined that the quantity of soil contaminated with cP AHs was considerably smaller than had been estimated earlier. Following the preparation of a Focused Feasibility Study by CRA, USEPA issued a ROD Amendment for OU 2 on May 31, 1994 that changed how SAAG would address the soil contaminated with cPAHs.

    The major components of the final amended au I remedy included:

    • Short-term monitoring of groundwater at the Site for approximately five years. Ten monitoring wells and one residential well would be sampled semiannually and analyzed for approximately thirty volatile organic and inorganic compounds.

    • Immediate resampling of wells if action levels (MCLs) are exceeded. If upon resampling action levels are exceeded, additional activities would be initiated.

    • Abandonment of those wells no longer being monitored. Wells would be abandoned in accordance with Minnesota Department of Health standards.

    • Additional monitoring if determined to be necessary upon review of the monitoring data.

    The 1988 ROD groundwater remedy consisted of four major components; three of these were deleted by the 1992 ROD Amendment. The deleted three components were: 1) extraction of groundwater from the surficial aquifer; 2) providing municipal water to private well users on or near the Site; and 3) placing restrictions on new wells on or near the Site. The fourth component, monitoring groundwater at the Site, was modified by the 1992 ROD Amendment. The remedial action objectives that were identified in the 1988 ROD included: 1) minimize the potential for direct contaminant consumption; 2) control contaminant migration to the lower sand aquifer; 3) control contaminant migration to surface water; and 4) provide measures that will be consistent with the final site recommendations. The action levels for groundwater at the Site are the MCLs. At the time of the decision documents for the groundwater, the Minnesota Department of Health

    had health based criteria for contaminants in drinking water referred to as recommended allowable limits (RALs). In the case of public water systems, RALs were used as guidelines with MCLs being the regulatory standard. Subsequently, the RALs have been replaced by health risk limits.

    The major components of the final amended OU 2 remedy included:

    Excavation and transportation of the predominately cPAH-contaminated soils to a facility for thermal treatment in either a rotary kiln incinerator or a low temperature thermal desorption unit.

    • Excavation and transportation for disposal approximately 9,300 cubic yards of soils

    contaminated with PCBs, cP AHs, lead, and antimony to an off-site solid waste landfill

    permitted to receive industrial and/or commercial wastes.

    • Sampling, characterization, transportation, and disposal of drums previously inventoried by MPCA and USEP A.

    • The ROD Amendment served to update the MCLs for several constituents which were

    being monitored in groundwater.

    The ROD Amendment stated that groundwater monitoring would terminate three years

    after all excavation activities had been completed.

    South Andover Site--Five-Year Review Report -6- June2011

  • The 1991 ROD stated that the approximately 2,100 cubic yards of predominately cP AHcontaminated soils would be excavated and treated using an above-ground biological treatment unit. The amended soil remedy did not require any institutional controls.

    The objectives of the remediation were to remove the contaminated soils and to monitor the groundwater until the action levels were met. The 1991 ROD stated, "The remedial action objective for soil is to clean-up the contaminants of concern to a level which is protective of human health."

    Remedy Implementation

    As reported in the December 1994 Remedial Action Reportfor Operable Unit 2, the soil work was conducted between July and October 1994 and include excavation, transportation, and offsite disposal or off-site treatment of contaminated soils. Within each excavation area, samples were collected to delineate and chaFacterize the nature and extent of contamination. Once the excavation was completed, demonstration of cleanup compliance was conducted through the collection and analysis of verification samples. Excavation within one area involved coordination with existing salvage operations on the Site. Within this area, areas of excavation were segregated from the salvage operations in order to isolate contaminated work areas from the salvage operations.

    Groundwater and wetland dewatering was required within other areas in order to lower the water table and facilitate removal of soils. Non-wetland areas were backfilled with clean fill material to pre-existing grades. Excavations within wetland areas were not backfilled in order to increase potential wetland areas. One of the areas was revegetated to restore the existing vegetative cover.

    During the remedial program, a total of 38 drums were recovered. These drums were characterized and were incinerated as hazardous waste. In addition, one capacitor was recovered and found to contain PCBs. This capacitor was incinerated as a Toxic Substance Control Act waste.

    During the excavation of the contaminated areas, when tires were encountered they were decontaminated and recycled at a local tire recycling facility. The cPAH-contaminated soils excavated during the remedial actions were transported to Soil Remediation Services in Tomah, Wisconsin for thennal treatment. The treated soil was subsequently disposed of at the USPCI facility in Rosemount, Minnesota. The total amount of soil sent to Soil Remediation Services and disposed of at USPCI was 88 cubic yards.

    The future activities planned for the Site following the completion of the remedial action were continued monitoring of surface water and sediment from on-site wetlands and groundwater monitoring for a period of three years.

    In November 1993, Phase I of the well abandonment was completed and in September 1994, Phase II was completed. However, several wells in the Phase II program were not abandoned because of the presence of trichloroethene (TCE) and tetrachloroethene (PCE) at well W21 B.

    The Preliminary Close Out Report was signed November I, 1994. The report signified construction completion at the Site.

    Institutional Controls

    Institutional controls (ICs) are non-engineered instruments, such as administrative and legal

    South Andover Site--Five-Year Review Report -7- June 201 1

  • controls, that help to minimize the potential for exposure to contamination and that protect the integrity of the remedy. ICs are required to assure long-term protectiveness for any areas which do not allow for unlimited use or unrestricted exposure (UU/UE).

    The groundwater under the Site does not currently allow for UU/UE. The soils do allow for UU/UE. The groundwater and soil remedies described in the 1991 ROD and the 1992 and 1994 ROD Amendments did not include institutional controls.

    Since the previous five-year review, the contractor for the SAAG investigated the ordinance that the City of Andover has in place regarding the installation of wells. Title 10, Chapter 1 of the Andover City Code covers the public water system. Section 10-1-18 of the Andover City Code covers private wells. It prohibits installation of private water systems for human consumption where municipal water is available, requires both "new" and "existing" homes and buildings to connect to the public system where available, and contains enforcement provisions whereby violations are misdemeanors punishable by tine or incarceration. Also, any private wells no longer used after connection to the public system must be sealed and properly abandoned. There are no sunset provisions applicable to this section of the code. The plume area is entirely within the boundaries of the City of Andover, and thus subject to the jurisdiction of the code. See Figure 4. The City of Andover public water supply system supplies water to residences at or near the plume area, and thus municipal water is available. All homes and buildings (whether new or existing) who are potentially affected by the plume are obligated to be connected to the public system, as are any future homes or buildings. The City will not issue a Certificate of Occupancy allowing occupancy of a home or building unless it is connected to the municipal water supply. Property owners are not permitted to disconnect from the system. The City of Andover also checked the properties that the contractor identified and represented in writing that all were connected to the water system except for a few properties that did not contain buildings because they were common lots around multi-unit townhouse buildings, or, in one case, part of a retention pond site. These properties were near or in the area of the groundwater plume.

    The contractor also contacted the City of Coon Rapids due to its proximity to the Site. The Coon Rapids City Code contains restrictions similar to those in Andover. If the plume were to move closer to Coon Rapids, specific addresses can be checked to make sure there are no wells that will be affected.

    With the City of Andover code restrictions and long-term stewardship procedures, consisting of additional groundwater monitoring and an annual verification to determine that no changes in the code have been made that would allow for the installation of private wells for human consumption, in place, the institutional control in place is effective in both the interim and longterm.

    Monitoring

    The first round ofpost-RA monitoring was initiated in October 1994 and the sixth round was performed in May 1997, which completed the required three years of monitoring.

    As reported in the July 1997 Semiannual Monitoring and Progress Report - Spring 1997, the last of the monitoring reports for the three-year monitoring program required by the decision documents, the City of Andover had taken, or was in the process of taking, ownership of the majority of the Site. The City had begun to clear and grade the Site for development as a commercial/industrial park. The grading atfected some of the monitoring wells on the Site and also impacted several of the areas that were part of the remedial activities conducted in 1994. The scrap, rubbish and other waste removals and Site grading were being conducted by the City

    South Andover Site--Five-Year Review Report -8- June2011

  • under the MPCA Voluntary Investigation and Cleanup (VIC) program. A Contingency Plan had been prepared and submitted to the MPCA to address these activities.

    In the July 1997 report, SAAG included the following conclusions concerning the remedial action:

    • Impacts to the wetlands had diminished to negligible levels and no further remedial actions were believed to be necessary.

    • No impacts to the groundwater in the lower aquifer resulting from Site activities had been detected. Further sampling of the lower aquifer was believed to be unnecessary.

    • The monitoring of the upper groundwater aquifer indicated that there was no "plume" of contamination at the Site but it did indicate that isolated areas or "hot spots" were found on the Site and that the compounds found in the upper aquifer vary from location to location. At the beginning of the monitoring program, groundwater samples from well W21 B contained arsenic, TCE and PCE above the MCLs. The levels of PCE and TCE declined steadily over the monitoring period and were currently at non-detect levels. Arsenic was continuing to be detected at levels just above the MCL and might represent a background condition. Groundwater samples from well WI9A had not had detections of any VOC compounds specified in the ROD. However, vinyl chloride was detected at 5.5 micrograms per liter (~g/l) in the spring 1996 round, 59 ~g/l in the fall 1996 round, and 7.8 ~g/l in the spring 1997 round. (Vinyl chloride was not one of the VOCs specified in the 1988 ROD and it was not one of the constituents listed to be monitored in the 1992 ROD Amendment. However, it was mentioned as having been detected at up to 12 ~g/I in the February 1991 Final Design Investigation Report, which had been used for the 1992 ROD Amendment.) These levels are above the MCL of2 ~g/l. No other VOCs had exceeded an MCL. Groundwater samples from well W23A-R had been at non-detect levels for all V OCs unti I the spring 1997 round when J, J ,2-trichloroethane (1,1,2-TCA) was detected at 54 and 37 ~g/l in the sample and duplicate sample, respectively. The MCL for I, I ,2-TC A is 5 ~g/l. PCE was detected in samples from well WIA during the sampling period. The PCE levels had been steadily dropping from its initial level of 6.2 ~g/l to non-detect in the final round. The MCL for PCE is 5 ~g/l. Samples from well WIB had MCL exceedences for I,2-dichloroethane (l,2-DCA), 1,1,2-TCA. and vinyl chloride during the sampling period. 1,2-DCA is a compound cited in the ROD and statement of work (SOW). It had been detected at levels of 17 to 45 ~g/I, which is above its MCL of 5 ~g/l. 1,1,2-TCA is not a ROD compound and has only been tested for in the last two rounds of the sampling period. 1,1,2-TCA was found at 18 to 23 ~gll and has an MCL of 5 ~g/l. Vinyl chloride was also not specified in the ROD or SOW, but has been tested for by the SAAG. The levels of vinyl chloride have ranged from 215 to 130 ~g/l. The vinyl chloride concentrations seemed to be declining, but no trend could be detected for 1,1,2-TCA and J,2-DCA.

    In a September 17, 1997 letter, the SAAG's contractor reported on a natural attenuation study and the results of two rounds of sampling. The sampling program used some of the existing wells and some Geoprobes, temporary 2-inch PVC wells, for collecting groundwater samples. The contractor stated that the groundwater sampling program had identified a chlorinated VOC plume emanating from the Site towards the west-southwest. Vinyl chloride was the primary VOC within this plume along with other parent VOCs, such as TCE. Analytical results collected from seven temporary well locations and three monitoring wells (WIA, WIB, and W23A-R) had provided evidence that intrinsic bioremediation of the chlorinated VOCs was occurring within the upper sand aquifer. The groundwater samples showed that the plume was restricted primarily to the lower zone of the upper sand aquifer, between 25 feet and 50 feet bgs, and had a narrow width (less than 300 feet). The plume length had not been completely detined, but it was likely that it extended up to 800 feet beyond well WI B. In round I (July 30-31, 1997), the vinyl

    South Andover Site--Five-Year Review Report -9- June2011

  • chloride concentration in well WI B was 140 Ilg/1 and in Geoprobe GP-l D, which was about 170 ft west of well W 1 B, it was 120 Ilg/l. In round 2 (August 19-21, 1997), the vinyl chloride concentration in well WI B was 130 Ilg/l, in Geoprobe GP-l D it was 200 Ilg/l, and in Geoprobe GP-6, which was near the Thrush St. NW cul-de-sac, about 400 ft west-southwest of well WI B, it was 75 ~lg/l.

    Computer modeling was done and the results suggested that the vinyl chloride plume would not extend beyond 1,000 feet from the Site. A well survey was conducted within a one-half mile radius (2,600 feet) of the nested well location WI that was focused on the area that is hydraulically downgradient (west and south) of well WIB. The well survey did not identifY any residential wells within this radius to the south or west; Coon Creek was not within the one-half mile radius. Thus it was concluded that the attenuation of the vinyl chloride plume within 1,000 feet of the site did not appear to pose an immediate threat to potential human or ecological receptors.

    In an August 21, 1998 letter, the SAAG's contractor reported on round 3 (May 11-19, 1998) of the sampling for the natural attenuation study. In this round, in Geoprobe GP-15, which was located near Thrush St. NW, about 550 feet southwest of well WI B, the vinyl chloride concentration was 170 Ilg/l. In the Summary, the contractor stated: "The groundwater chemistry downgradient from the Site documents natural attenuation of vinyl chloride within the Upper Sand Aquifer, a non-potable aquifer. Analytical data and transport modeling show that the vinyl chloride plume is of limited extent and is attenuated within approximately 1,300 feet from the Site." The contractor recommended some semi-annual monitoring for three years to check that the chlorinated VOC plume continued to attenuate. A monitoring program was not set up due to the inability to obtain access from the City of Andover. However, since the last five-year review a monitoring program has been set up. The results of this are discussed below.

    In the September 15, 1998 Federal Register, the USEPA published a notice of intent to delete OU 2 of the Site from the National Priorities List and requested comments on this. The partial deletion was being taken by USEP A because it had been determined that the responsible parties had implemented all response actions required and USEP A, in consultation with the State of Minnesota, had determined that no further response was appropriate for this particular operable unit. USEPA and the State had determined that remedial activities conducted at the Site to date had been protective of public health, welfare, and the environment. In the October 28, 1998 Federal Register, USEPA announced the deletion ofOU 2 of the Site from the NPL; no comments had been received. This did not delete OU I. In the August 18, 2006 Federal Register, USEPA published a technical correction concerning the partial deletion.

    On April 25, 2000, MPCA certified that response actions had been completed as set forth in the approved voluntary response action plan for the site that had been submitted by the City of Andover. According to the Site Summary that was included with the Certificate, the response actions that the City completed covered an area larger than that of the Superfund site; this site contains about 90 acres and is roughly a rectangular property that originally included 24 separate parcels. This South Andover Redevelopment Site is bounded on the north by Bunker Lake Boulevard, on the west by Thrush Street Northwest, on the southwest by developed residential properties, on the southeast by Commercial Boulevard Northwest, and on the east by Jay Street. The City'S initial plan was designed as a Site Contingency Plan whose purpose was to specifY how potentially hazardous materials were to be screened, characterized, and remediated as the City graded and prepared the site for redevelopment. The Site Contingency Plan, parcel-specific investigations, and interim response action proposals were implemented by the City to identify and remediate additional areas of soil contamination not previously addressed during the Superfund site investigation. The Site Summary includes a table that summarizes the response

    South Andover Site--Five-Year Review Report -10- June 2011

  • actions performed on the various parcels.

    In a letter dated February 21, 2001, the SAAG's contractor reported the results on a November 2000 sample from well WI B; the vinyl chloride concentration was O.79J ~g/l whereas in 1997 it was 140 ~g/l in July and 130 ~g/l in August. (The J flag for a concentration means that the associated value for the detected analyte is an estimated quantity.) In a January 23,2002 letter, SAAG's contractor reported the results of the analysis of a sample that had been taken from well WIB on September 20,2001. The vinyl chloride concentration in this well was 3.8 ~g/l. The sample also contained 3.9 ~g/l of TCE and 0.3 8J ~g/l of PCE.

    In a September 11, 2006 letter, the SAAG's contractor reported the results of the analysis of a sample taken from well WI B on August 6, 2006. The sample contained four VOCs: 1,1dichloroethane (l,I-DCA) at 8.7 ~g/l; 1,2-DCA at 5.6 ~g/l; TCE at 6.8 ~g/l; and vinyl chloride at 41 ~g/l. Although this vinyl chloride concentration was an increase over the concentrations in 2000 and 2001, it is significantly below the concentrations that were seen in the 1995 to 1997 period when the concentrations ranged from over 200 ~g/l down to around 150 ~g/l.

    The results of the monitoring done within the last five years are discussed in the following section.

    v. Progress Since the Last Five-Year Review

    Three geoprobe investigations (December 2007, July 2009, and September 2010) were performed by SAAG's contractor during the last five years. In these investigations, four wells on or near the Site, three geoprobes, each at two elevations, in the Thrush St. NW cul-de-sac area, three geoprobes along 135th Av. N.W., between Thrush and Uplander, and one geoprobe at the southwest comer of the Site were sampled. Samples were analyzed for several VOCs, dissolved gases, and some groundwater quality parameters. The predominant VOC detected was vinyl chloride. In 2007, vinyl chloride concentrations were 20 ~g/l in well WI B, which is installed in the lower portion of the Upper Sand Aquifer and is located about 250 ft west of the southwest comer of the Site, a maximum of 50 )lg/l in the lower portion of the Upper Sand Aquifer in the cul-de-sac area, and a maximum of 12 ~g/l along 135th Ave. In 2009, vinyl chloride concentrations were detected at 1.3 ~g/l in well WIB, at a maximum of22 )lg/l in the lower portion of the Upper Sand Aquifer in the cul-de-sac area, and at non-detect along 135th Ave. In 2010, vinyl chloride concentrations were an estimated 0.42J 1lg/1 in well WIB, a maximum of 35 ~g/I in the lower portion of the Upper Sand Aquifer in the cul-de-sac area, and non-detect along 135th Ave. All samples from the upper portion of the Upper Sand Aquifer were below detection limits in all three sampling events. Other VOCs were detected but typically at concentrations less than 5~g/l. Some concentrations of vinyl chloride and 1,2-DCA exceeded their MCLs at some locations in all three rounds; in the first round, one concentration of TeE exceeded its MCL.

    The fact that VOCs were not detected in the upper portion of the Upper Sand Aquifer indicates that the contamination in the aquifer is not getting into the unsaturated soil where it could move inside structures via vapor-phase transport and result in a vapor intrusion problem.

    . . mthe prevIOus fiIve-year review an d h Th ese are t he Issues raise d' t elr status. .

    Issue Recommendation Status

    Groundwater contamination remains

    PRPs need to perform additional groundwater sampling

    Additional groundwater sampling was performed. Periodic groundwater sampling will need to be continued.

    South Andover Site--Five-Year Review Report -11- June 2011

  • Issue Recommendation Status

    Potential for an indoor air problem Evaluate this possibility. The absence of VOC contamination in the upper portion of the Upper Sand Aquifer indicates that this is not a problem.

    ICs. Complete IC study and develop a plan

    Completed.

    VI. Five-Year Review Process

    Administrative Components

    USEPA initiated the third five-year review for the Site in April 2011. USEPA informed the state's project manager and the SAAG's contractor that the five-year review was to be done.

    The review consisted of: document review; data review; Site inspection; and report development and review.

    Community Notification and Involvement

    No comments have been received concerning this review. SAAG's contractor has contacted the City of Andover and the City of Coon Rapids during the past five years to obtain information regarding their regulations for private wells within their cities. This information was provided.

    Document Review

    The review is based upon the Site 'visit, discussions with the state project manager and the CRA representative, reports on the various investigations and analyses, the decision documents, and the reports on the results of the monitoring that has been performed since remedy construction was completed. Attachment A contains a list of the documents that were used for the review.

    Data Review

    USEP A reviewed the data from the monitoring that was performed during the initial three-year period of monitoring required after the completion of construction of the original remedies. Also reviewed were the letter reports for the natural attenuation study, the letter reports providing the results of some limited monitoring, and the reports on the three geoprobe investigations that have been performed during the past live years.

    Site Inspection

    The USEP A RPM, the MPCA project manager, and the CRA representative who has been working on the Site for a number of years visited the site on May 24, 2011.

    A large portion of the Site has been commercially developed. Buildings and parking lots cover much of this area, but there are two retention ponds within grassy areas on this part of the Site. In the southwest corner of the Site is a townhouse development. South of the Site is a residential area. There are also homes in the Thrush St. NW cul-de-sac area. Figure 3 is an aerial photograph of the area.

    South Andover Site--Five-Year Review Report -12- June 2011

  • The development that has taken place has been a good use for the property. There are still a few monitoring wells located on the property, which are not very visible. The development fits in very well with its surroundings.

    VII. Technical Assessment

    Question A. Is the remedy functioning as intended by the decision documents?

    Yes.

    All appropriate response actions required for the soils (OU 2) have been implemented and this operable unit has been deleted from the NPL. The groundwater was monitored for the length of time specified in the decision documents. Additional groundwater monitoring performed indicates that the concentrations are generally decreasing. An IC study and a plan have been developed and these found that a governmental control is in place that applies to the plume area. The Andover City Code contains prohibitions against the installation of wells where municipal water is available. Municipal water is available in the area of concern. All parcels in the plume area were found to be connected to municipal water except for a few that do not contain buildings.

    Question B. Are the exposure assumptions, toxicity data, clean-up levels, and remedial action objectives used at the time of the remedy selection still valid?

    No.

    The exposure assumptions, clean-up levels, and remedial action objectives concerning the problems that were addressed in the decision documents, have remained the same for both OUs, except for the change in the MCL for arsenic (50 Ilg/1 to 10 Ilg/I); arsenic had been found at a concentration greater than its MCL in only one well during the R1 and no on-site arsenic source was ever identified.

    Question C. Has any other information come to light that could call into question the protectiveness of the remedy?

    No.

    Technical Assessment Summary

    Based on this review, the remedy has functioned in the manner intended. However, the vinyl chloride concentrations have remained high. Additional periodic groundwater sampling will be done.

    VIII. Issues

    VOC concentrations in the groundwater remain at levels in excess of MCLs.

    IX. Recommendations and Follow-Up Actions

    Continue the groundwater monitoring. This should be done about once every 30 months to monitor the concentrations of vinyl chloride and other VOCs.

    South Andover Site--Five-Year Review Report -13- June 2011

  • Issue Recommendationsl Follow-up Actions

    Party Responsible

    Oversight Agency

    Milestone Date

    Affects Protectiveness? (YIN)

    Current Future

    Groundwater contamination remains at concentrations in excess of MCLs

    Continue groundwater monitoring.

    PRPs USEPA March 2016

    N Y

    X. Protectiveness Statement

    For the soil, OU2, the remedy is considered protective in both the short-term and the long-term because there is no evidence of current or future exposure. For the groundwater, OUI, the remedy is considered protective in the short-term because there is no evidence of current exposure. Long-term protectiveness of the groundwater will be achieved when the groundwater reaches cleanup levels. For the entire site, the remedy is considered protective in the short-term because there is no evidence of current exposure. Site-wide long-term protectiveness will be achieved \\hen the groundwater reaches cleanup levels.

    XI. l\ I..\l Review

    The next five-vr> : l:view for the South Andover Site is required in June 2016, five years from the d(l' ;Vlew.

    South Andover Site--Five-Year Review Report - 1 4- June 2011

  • Attachment A

    Documents Consulted

    Andover City Code

    Final Remedial Investigation Report, CH2M Hill, January 29, 1988

    Public Comment Feasibility Study Report, CH2M Hill, January 29, 1988

    Record of Decision--Initial Groundwater Operable Unit, USEPA, March 30, 1988

    Final Design Investigation Report. South Andover. First Operable Unit, Donohue & Associates, Inc., February 1991

    Final Remedial Investigation Report, South Andover, Second Operable Unit Donohue &

    Associates, Inc., July 1991

    Final Feasibility Study Report jar South Andover Superfund Site Second Operable Unit, Donohue & Associates, Inc., December 1991

    Record of Decision (soil operable unit remedial action), USEPA, December 24,1991 .

    Record of Decision Amendment (groundwater remedial action), USEPA, June 9, 1992

    Consent Decree, United States and South Andover Administrative Group, entered August 27, 1993

    Record of Decision Amendment (soil remedial action), US EPA, May 31, 1994

    Remedial Action Reportfor Operable Unit 2 (Soil Remediation), Conestoga-Rovers & Associates, December 1994

    Focused Feasibility Study (South Andover Superfund Site), Conestoga-Rovers & Associates, March 1994

    Preliminary Site Close Out Report, USEPA, November 1, 1994

    Semiannual Monitoring and Progress Report - Spring 1997, Conestoga-Rovers & Associates, July 1997

    Letter Report: "Natural Attenuation Study, South Andover Superfund Site", Conestoga-Rovers & Associates, September 17, 1997

    Letter: "Abandonment of Monitoring Wells; South Andover Superfund Site; Andover, MN", USEPA, February 13, 1998

    Letter Report: "Natural Attenuation Study - Round 3, South Andover Superfund Site", Conestoga-Rovers & Associates, August 21, 1998

    "Notice of intent to delete Operable Unit 2 of the South Andover Salvage Yards site from the National Priorities List; request for comments.", USEP A, Federal Register, September

    South Andover Site--Five-Year Review Report -15- June 2011

  • 15,1998

    "Final rule; notice of deletion of the Operable Unit 2 of the South Andover Salvage Yards Superfund site from the National Priorities List (NPL).", Federal Register, October 28, 1998

    "Commissioner's Certificate of Completion of Response Actions Under the Land Recycling Act of 1992, As Amended", MPCA, April 25, 2000

    First Five-Year Review Report For South Andover Salvage Yard, US EPA, September 28,2001

    Letter Report: "Recent Groundwater Sampling Results from Monitoring Well WIB, Vapor Migration Model Evaluation and Associated Risk Assessment, and a Proposed Off-Site Groundwater Sampling Program", Conestoga-Rovers & Associates, January 23,2002

    Memorandum: "Approval of the November 2003 Update of the Minnesota Environmental Response and Liability Act Permanent List of Priorities", MPCA, November 21, 2003

    Letter: Contingent approval of CRA's revised work plan, USEPA, March 12, 2004

    Letter: "Geoprobe Investigation, South Andover Superfund Site", CRA, April 16,2004

    South Andover (MND98060961-1) Statistical Ana(ysis Report--Sampling Period: 12/1979 to 05/1998, Volpe National Transportation Systems Center, U.S. Department of Transportation, June 2004

    "Technical Correction of final partial deletion of the South Andover Salvage Yards Superfund Site from the National Priorities List.", Federal Register, August 18, 2006

    Letter Report: "WIB Sample Results, South Andover Superfund Site", Conestoga-Rovers & Associates, September 11, 2006

    Second Five-Year Review Report, South Andover Site, USEPA, September 29,2006

    Letter Report: "South Andover Superfund Site, Institutional Controls Investigation/Study", Conestoga-Rovers & Associates, June 11,2007

    Letter Report: "Geoprobe Investigation Results, South Andover Superfund Site", ConestogaRovers & Associates, February 22,2008

    Letter Report: "Response to USEPA Comments, Geoprobe Investigation, South Andover Superfund Site", Conestoga-Rovers & Associates, October 2,2008

    Letter Report: "Institutional Control (IC) Monitoring Plan, South Andover Superfund Site", Conestoga-Rovers & Associates, December 9,2008

    Letter Report: "July 2009 Geoprobe Investigation Results, South Andover Superfund Site", Conestoga-Rovers & Associates, October 7, 2009

    Letter Report: "September 2010 Geoprobe Investigation Results, South Andover Superfund Site", Conestoga-Rovers & Associates, December 17,2010

    South Andover Site--Five-Year Review Report -\6- June20\\

  • ----

    ---

    ------~--------------~I~----r-----~------------~I~~-------------I I I I I I , I I I

    ""'UI..IQ I IQI I 61.110"•• ," II' II I~' ! I

    : : ..... \1: aI I •.•,.ulaU.,. I ,I ~

    I I I,

    I I I

    I ,

    I I

    -----,-, I

    , , I

    a....... I I I ....., I I 1 I I I , I

    I 1 I-------,& 1_____-------------I· ,

    III

    II,

    &10 __ li\

    II'------:.1 , :

    · ....-at , ' 1 , I :I r-------'---------------

    --~-__r-------7---------------------------, , 0 1 I

    ......LllMIWar: .'11 : _.. 1 1_" , 1·--1 """-r-'----.:.'___..:..'____...._------~--------------------------------

    --- .101 ....... ' .........u-II..

    • _"J:t~JnIi" ,.;AIfL.~'DA.,.MG~ ..tl \:J "....&M~

    U.U

    1..........._ ..... 'IN'-- ..

    ~I.t .. , .... U' , ... 1_.......... a.I_la... ~

    ~ ..........-.~

    Figure 1. Site boundaries and reported waste disposal activities, South Andover Site. (from Final Design Investigation Report, Donohue, Inc., February 1991)

    South Andover Site--Five-Year Review Report -17- June 201 I

  • r

    • w, ..

    I ~ ./ .. [1 ON

    \",.. ( \. _./

    , -. ,

    PI CllJIoClI.M I..D(;Al1CIN

    slJlltr...'"t.,. IL_ ..,..0 ~~lQoJ.looo.o.

    I •

    ~ I I

    SITE r'LAN SOlJln Andovtlr Siltt

    Figure 2. Locations of monitoring wells.

    (from letter report "Natural Attenuation Study", Conestoga-Rovers & Associates, September 17, 1997)

    South Andover Site--Five-Year Review Report -18- June 2011

  • ApproXl!Ilate Site bOWldary ---

    I

    ""041 PlOto flOwn Spnng 2008

    )/ ~i II'

    Figure 3. Approximate Site boundary shown on a recent aerial photo of the area.

    South Andover Site--Five-Year Review Report -19- June 2011

  • Approximate locallon of city limits ofAndover

    Approximate center of the plume

    J\eual Pnoto. Fk>wn Svung 200'

    ._..--

    Figure 4. Location of plume within Andover city limits.

    South Andover Site--Five-Year Review Report -20- June2011