i
FIVE-YEAR REVIEW REPORT FDR
TANSITOR ELECTRONICS INC. StJPERFUND SITE
BENNINGTON COUNTY, VERMONT
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I'repared by
ll,S, Environmental Protfti'finn Aganry
Reginn I
DOSTON, MASSACHUSETTS
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fire of Site Rcmcitialion und RisLursifhin
SDMS Doc ID 565823
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THIS PAGE INTENTIONALLY LEFT BLANK
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2014 FIVE-YEAR REVIEW
TANSITOR ELECTRONICS INC. SUPERFUND SITE
TABLE OF CONTENTS
EXECUTIVE SUMMARY
I. INTRODUCTION 1
II. PROGRESS SINCE THE LAST REVIEW 2
III. FIVE-YEAR REVIEW PROCESS 5
IV. TECHNICAL ASSESSMENT 14
V. ISSUES/RECOMMENDATIONS AND FOLLOW-UP ACTIONS 17
VI. PROTECTIVENESS STATEMENTS 17
VII. NEXT REVIEW 17
TABLES
Table 1: Protectiveness Determinations/Statements from the 2009 FYR 2
Table 2: Status of Follow-up Actions from the 2009 FYR 3
Table 3: Summary of Planned and/or Implemented ICs 4
Table 4: COCs (in ppb) 7
FIGURES
Figure 1: Groundwater Contour Plan 8
Figure 2: Hydrogeologic Cross Section 9
Figure 3: Exponential Decay Curve for monitoring well ERM-2S 10
Figure 4: Exponential Decay Curve for monitoring well MW-112U 11
Figure 5: Exponential Decay Curve for monitoring well MW-112U 12
APPENDICES
A EXISTING SITE INFORMATION
B ADDITIONAL FIGURES FOR REFERENCE
C PRESS RELEASE ANNOUNCING FIVE-YEAR REVIEW
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LIST OF ACRONYMS
ARAR
Applicable or Relevant and Appropriate Requirement
COC
Contaminant of Concern
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act
CFR
Code of Federal Regulations
DCA
1,1-dichloroethane
DCE
1,1-dichloroethene
EPA
U.S. Environmental Protection Agency
FYR
Five-Year Review
GWPRS
Vermont Ground Water Protection Rule and Strategy
MCL
Maximum Contaminant Level
NCP
National Contingency Plan
NPL
National Priorities List
O&M
Operations and Maintenance
PCE
T etrachl oroethy 1 ene
PGWS
Vermont Primary Groundwater Quality Standards
ppb
parts per billion
PRPs
Potentially Responsible Parties
RAO
Remedial Action Objective
RI/FS
Remedial Investigation/Feasibility Study
ROD
Record of Decision
TBC
To be Considered
TCA
1,1,1 -trichloroethane
TCE
T ri chl oroethy 1 ene
TI Zone
Technically Impracticability Zone
VOC
volatile organic compound
VTANR
Vermont Agency of Natural Resources
UU/UE
Unlimited Use/Unlimited Exposure
Vgfi
micrograms per liter
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EXECUTIVE SUMMARY
This is the third Five-Year Review (FYR) for the Tansitor Electronics Inc. Superfund Site (Site)
located in Bennington, Bennington County, Vermont. The purpose of this FYR is to review
information to determine if the remedy is and will continue to be protective of human health and
the environment. The triggering action for this statutory FYR was the signing of the previous
FYR on September 23, 2009.
Since the 1950s, various owners have used the Site as a manufacturing facility for electronic
capacitors. Between 1956 and 1979, organic solvents and acids were disposed of in two areas of
the property. During the period of 1975-1979, the process waste disposed included 1,1,1-
trichloroethane (TCA) which is the predominant volatile organic compound (VOC) present in the
groundwater. The Site owner/operator, Vishay-Tansitor Electronics, Inc. (formerly Tansitor
Electronics, Inc., hereafter, "Vishay-Tansitor") also reported that some waste detergents and
dilute acid solutions may have been discharged into two leach fields or directly into the
intermittent stream north of its manufacturing building.
In May 1981, in compliance with Section 103(c) of CERCLA, Vishay-Tansitor notified EPA of
the waste disposal. Subsequent to the notification, the Vermont Agency of Natural Resources
(VTANR) performed site inspections and requested that Vishay-Tansitor initiate removal
activities and implement a soil sampling and analysis program in the "Disposal Area." The Site
was listed on the National Priorities List in October 1989. On September 29, 1995, EPA issued a
Record of Decision (ROD) which set forth the selected remedy for the Site. The major
components of the selected remedy included institutional controls to prevent use of groundwater,
long-term monitoring of Site groundwater, contingencies for additional investigation or further
action, and five-year reviews.
In addition, as part of the selected remedy, for a ten-acre portion of the Site, EPA waived the
attainment of federal drinking water standards which are applicable or relevant and appropriate
requirements (ARARs). EPA waived attainment of these ARARs on the basis that it was
technically impracticable from an engineering perspective to restore groundwater to drinking
water standards for this ten-acre portion of the Site within a reasonable timeframe. This
followed the State of Vermont's reclassification of the groundwater beneath the Technical
Impracticability Zone (TI Zone) to non-potable use only.
Pursuant to a Consent Decree, Vishay-Tansitor and Siemens Communication Systems, Inc. (the
"Settling PRPs") recorded institutional controls and are performing the long-term sampling
program established in the ROD. Three of the contingencies for additional monitoring outlined
in the ROD have been triggered since 1995 by the groundwater monitoring data. As a result, the
sampling frequency was increased and a conceptual model evaluation plan and a phased bedrock
monitoring plan were submitted and approved.
In September 1999, EPA deleted the Site from the National Priorities List, and, on December 3,
1999, VTANR formally accepted lead agency responsibilities.
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Based on the data reviewed for this FYR, observations from the site inspection, and interviews,
the remedy is functioning as intended by the ROD. Groundwater monitoring continues,
maintenance of the wells is performed as necessary, and the effective implementation of
institutional controls has thus far ensured the integrity of the remedy and prevented exposure to
Site groundwater.
The primary ARARs for groundwater beyond the TI Zone are Maximum Contaminant Levels
and Vermont Primary Groundwater Quality Standards. These standards continue to be met in
the wells outside the TI Zone. Land use at the Site has not changed since the 1995 ROD and is
not expected to change in the near future.
No current issues were raised by this five-year review.
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Five-Year Review Summary Form
SITE IDENTIFICATION
Site Name: Tansitor Electronics Inc. Superfund Site
EPA ID:
VTD000509174
Region: 1
State: Vermont
Town/County: Bennington/Bennington County
NPL Status: Deleted
Multiple OUs?
No
Has the site achieved construction completion?
Yes
Lead agency: State
Author name (Federal or State Project Manager): Terrence Connelly
Author affiliation: EPA
Review period: 4/8/2014 - 9/30/2014
Date of site inspection: May 7, 2014
Type of review: Statutory
Review number: 3
Triggering action date: 9/23/2009
Due date (fiveyears after triggering action date): 9/23/2014
OU(s) without Issues/Recommendations Identified in the Five-Year Review:
Sitewide
Protectiveness Determination: Addendum Due Date (if applicable):
Protective Not Applicable
Protectiveness Statement: The site-wide remedy is protective of human health and the
environment.
Institutional controls have been recorded. The institutional controls have prevented exposure
to Site groundwater, thereby ensuring the Site remains protective of human health. In
addition, the State of Vermont reclassified the groundwater beneath the TI Zone to non-
potable use only. Ongoing monitoring demonstrates that the plume is stable and not
migrating.
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I. INTRODUCTION
The purpose of a Five-Year Review (FYR) is to evaluate the implementation and performance of
a remedy in order to determine if the remedy will continue to be protective of human health and
the environment. The methods, findings, and conclusions of reviews are documented in five-
year review reports. In addition, FYR reports identify issues found during the review, if any, and
document recommendations to address them.
The U.S. Environmental Protection Agency (EPA) prepares FYRs pursuant to the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section
121 and the National Contingency Plan (NCP). 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 five 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 offacilities for which
such review is required, the results of all such reviews, and any actions taken as a
result of such reviews.
EPA interpreted this requirement further in the NCP; 40 Code of Federal Regulations (CFR)
Section 300.430(f)(4)(ii), which 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 actions no less often
than every five years after the initiation of the selected remedial action.
EPA has conducted two FYRs on the remedy implemented at the Tansitor Electronics, Inc.
Superfund Site (Site) in Bennington, Bennington County, Vermont. EPA was the lead agency
for developing and implementing the remedy for the Site. Vermont Agency of Natural
Resources (VTANR), as the support agency representing the State of Vermont during the
implementation of the remedy, has been the lead agency since 1999. VTANR reviewed all
supporting documentation and provided input to EPA for each FYR.
This is the third FYR for the Site. The triggering action for this statutory review is September
23, 2009, the completion date of the second FYR. This FYR is required since hazardous
substances, pollutants, or contaminants remain at the Site above levels that allow for unlimited
use and unrestricted exposure. The Site consists of one Operable Unit.
1
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II. PROGRESS SINCE THE LAST REVIEW
The second Five-Year Review Report was signed on September 23, 2009. The 2009 FYR found
that the site-wide remedy was protective because the remedial activities have been implemented
and are complete including an institutional control for the Site (July 28, 1999 Environmental
Protection Easement and Declaration of Restrictive Covenant). In addition, Vermont reclassified
the groundwater beneath the TI Zone to non-potable use only. Annual reports certify compliance
with the institutional controls and the Vermont Reclassification Order. Groundwater monitoring
within the TI zone has shown gradual reductions in concentrations of concern. Tables 1 and 2
below present the protectiveness determination and follow-up actions from the 2009 FYR. The
2009 FYR carried forward four potential issues from the 2004 FYR and follow-up
recommendations/actions.
Table 1: Protectiveness Determinations/Statements from the 2009 FYR
ou#
Protectiveness
Determination
Protectiveness Statement
1
Protective
Because the remedy selected for the Site is protective, the Site is protective of
human health and the environment. Institutional controls have been recorded. The
institutional controls prevent exposure to site groundwater ensuring the Site
remains protective of human health. In addition, Vermont reclassified the
groundwater beneath the TI Zone to non-potable use only. Annual reports certify
compliance with the institutional controls and the Vermont Reclassification Order.
Groundwater monitoring within the TI zone has shown gradual reductions in
concentrations of concern. Groundwater monitoring beneath and outside the TI
zone has demonstrated that there continues to be no migration beyond the TI zone
or the Site. The monitoring program will continue to ensure that no migration
beyond the TI zone or the Site occurs.
Although EPA does not consider the indoor migration pathway from the historic
source release to be complete for the current land use scenario, should future land
use change, there would be a need to reevaluate the indoor air pathway at that
time. EPA will continue to monitor land use in future reviews.
2
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Table 2: Status of Follow-up Actions from the 2009 FYR
ou
#
Potential Issue
Follow-up
Actions
Party
Responsible
Oversight
Party
Original
Milestone
Date
Current
Status
Completion
Date (if
applicable)
1
Reassessment
of 1,4-dioxane
toxicity
Re-evaluate
1,4-dioxane
data when
toxicity value
reassessed
EPA
N/A
2013
Completed
August 2014
1
Vapor
Intrusion
Monitor land
use at the Site
relative to the
vapor intrusion
pathway
State/EPA
N/A
2013
Ongoing
1
Institutional
Controls
Monitor land
use at the Site
relative to the
institutional
controls
State/EPA
N/A
2013
Ongoing
1
Viability of
Monitoring
Wells
Develop a
process to
address long-
term viability of
the monitoring
wells
Settling
Parties
VTANR/
EPA
2013
Ongoing
Follow-up Action 1
EPA updated the toxicity value of 1,4-dioxane in 2010 and 2013. EPA reassessed the
Site data using the updated value for this FYR. Changes in the toxicity values for
1,4-dioxane does not affect the protectiveness of the remedy because exposure to the
groundwater is prevented by institutional controls and geologic and hydrologic factors
prevent the plume from expanding beyond the extent characterized in the 1995 ROD.
Follow-up Action 2
EPA continues to monitor land use at the Site relative to the vapor intrusion pathway.
There has been no change in land use since the 1995 ROD. This type of monitoring will
continue in future FYRs and at this time no longer needs to be tracked as an issue related
to protectiveness.
Follow-up Action 3
EPA continues to monitor land use at the Site relative to the institutional control. There
has been no change in land use since the 1995 ROD and the restrictions continue to be
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followed. This type of monitoring will continue in future FYRs and at this time no longer
needs to be tracked as an issue related to protectiveness.
Follow-up Action 4
VTANR and EPA have discussed with the Settling Parties the eventuality of replacing of
the monitoring wells to maintain the long-term viability of the monitoring program. The
Settling Parties have made repairs to the well footings as needed. This type of monitoring
will continue in future FYRs and at this time no longer needs to be tracked as an issue
related to protectiveness.
Remedy Implementation Activities
No remedial implementation activities have been performed since the previous FYR, except for
the continued implementation of the institutional controls.
Table 3: Summary of Planned and/or Implemented ICs
Media,
engineered
controls, and
areas that do
not support
UU/UE based on
current
conditions
ICs
Needed
ICs Called
for in the
Decision
Document
Impacted
Parcel(s)
IC
Objective
Title of IC Instrument
Implemented and Date
(or planned)
Groundwater,
soil
Yes
Yes
Parcel # 1,
Book 0-221
and
Parcel #2,
Book 0-234
Use restriction or
notice provided by the
IC (e.g. restrict
installation of ground
water wells and
groundwater use and
no excavation or
construction within Tl
Zone).
Environmental
Protection Easement
and Declaration of
Restrictive Covenants,
July 1999
System Operation/Operation and Maintenance Activities
Neither the ROD nor Consent Decree specified any Operation and Maintenance tasks. With the
recording of the Environmental Easement and Declaration of Restrictive Covenants in July 1999,
the remedial action was determined to be complete per EPA's guidance. The monitoring wells
are maintained as part of regular grounds maintenance for the facility.
4
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III. FIVE-YEAR REVIEW PROCESS
Administrative Components
VTANR was notified of the initiation of the five-year review on April 8, 2014. The FYR was
led by Terrence Connelly, EPA's Remedial Project Manager for the Site. Michael Smith of
VTANR assisted in the review as the State Project Manager.
The review consisted of the following components:
Community Notification and Involvement;
Document Review;
Data Review;
Site Inspection; and
Interviews.
Community Notification and Involvement
Activities to involve the community in the five-year review process were initiated by the
Remedial Project Manager in April 2014 with a summary of the Site sent to the regional team.
Per Region 1 policy, a region-wide press release announcing all upcoming five-year reviews in
New England was sent to all regional newspapers including the Bennington Banner. The press
release was sent on February 13, 2014 and is attached in Appendix B. The results of the review
and this FYR will be made available at the Site information repository located at:
Bennington Free Library
101 Silver Street
Bennington, Vermont 05201
and at
Superfund Records Center
US Environmental Protection Agency
5 Post Office Square, Suite 100
Boston, MA 02109-3912
Document Review
This five-year review consisted of a review of relevant documents including decision documents,
monitoring reports, institutional controls, and trust fund annual financial reports. Groundwater
cleanup standards, as listed in the September 1995 ROD, were also reviewed.
Data Review - Groundwater
5
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The 2009 FYR provided a comprehensive review of data over the entire sampling program
through 2009 at each monitoring well on the Site and that review is included in Appendix A.
The current monitoring program consists of quarterly sampling of MW-105M and another
fourteen wells annually. Eight wells are within the TI Zone and plume, five within the TI Zone
but beyond the plume, and two are outside the TI Zone.
Overall, the monitoring data collected from April 2010 through May 2014 showed that the
groundwater flow conditions remain consistent with an upward flow into the Fire Pond,
concentrations are consistent with past data, the decreasing concentration trends noted in 2009
are continuing, and variation of seasonal precipitation appear to influence the fluctuations of
concentrations observed within the overall decreasing trends.
Flow Conditions
Figure 1, showing the groundwater potentiometric-level contours, monitoring well locations, and
the TI Zone, was generated from water level measurements taken on May 7, 2014. The
groundwater flow pattern shown on Figure 1 is consistent with that shown and described in the
ROD and in previous monitoring reports. Flow from the Disposal Area is toward and into the
Fire Pond and flow from the Concrete Pad Area is toward the Vishay-Tansitor manufacturing
building.
Figure 2, showing groundwater flow in cross-section (groundwater flow net) from the Disposal
Area to well MW-109, was generated from measurements taken in multi-level wells in May
2014. These figures demonstrate that the extent of contamination remains constrained by
geologic and hydrologic factors.
Water Quality Data
The 1995 ROD set MCLs as the groundwater performance standards for the groundwater
Contaminants of Concern (COCs) and identified five major COCs: 1,1,1-trichloroethane (TCA),
1,1-dichloroethylene (DCE), trichloroethylene (TCE), tetrachloroethylene (PCE), and vinyl
chloride. The ROD stated that the increased carcinogenic risk from ingestion of groundwater
was exclusively due to DCE and the increased non-carcinogenic risk was mostly due to TCA and
DCE.
Monitoring continues to detect TCA and DCE at concentrations above their respective MCL
north of the Fire Pond whereas TCE and PCE (historically detected only in the Concrete Pad
Plume) concentrations have decreased such that they met their respective MCL during this
review period. Vinyl chloride was only detected in MW-ELF prior to the 1995 ROD. With
modification to the facility's floor drain system, vinyl chloride has no longer been detected at the
Site. In addition to the five major COCs, 1,1-dichloroethane (DCA) has been detected in the
shallow overburden wells located in the Disposal Area Plume. There is no MCL or VT Primary
Groundwater Quality Standard for DCA (the 1995 ROD identified the Ground Water Protection
6
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Rule Strategy or GWPRS as the ARAR. The State of Vermont replaced it in 2005 with the
PGQS). The ROD did not indicate that DCA contributed to either the carcinogenic or non-
carcinogenic risk associated with ingestion of drinking the groundwater; and DCA
concentrations have decreased by an order of magnitude or more in four of the five wells where
it has been detected.
Table 4 below presents the maximum and current concentrations of TCA, DCE, TCE, PCE, and
DCA in the two plumes. As stated previously, none of the COCs has ever been detected
downgradient of the Fire Pond or in the facility's bedrock production well.
Table 4: COCs (in ppb)
coc
MCL
Location1
Historical Maximum
Concentration and Date
Current Concentration
(May 2014)
Disposal Area Plume
TCA
200
ERM-2S
420,000 Oct 1994
3,400
MW-112U
22,000 Apr 2002
3,500
MW-112M
810 Oct 2002
260
MW-104U
2,100 Oct 2008
170
MW-104M
330 Jan 2002
50
DCE
7
ERM-2S
5,200 Oct 1994
140
MW-112U
1,200 Apr 2002
270
MW-112M
200 April 2010
140
MW-104U
54 Oct 2008
5.8
MW-104M
150 April 2013
18
DCA
NS
ERM-2S
3,200 Oct 2000
14
MW-112U
18,000 April 2002
200
MW-112M
1.2 April 2005
ND
MW-104U
1,400 Oct 2008
130
MW-104M
6.4 Oct 1999
0.61
Concrete Pad Plume
TCA
200
MW-108U
3,200 Oct 1995
1.8
DCE
7
850 Oct 1995
ND
TCE
5
94 May 1997
1.3
PCE
5
130 May 1997
2.1
DCA
NS
570 April 2002
ND
1 Monitoring locations are listed by distance from the Disposal Area
NS: No Standard
ND: Not Detected
7
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Trends
Figures 3-5 present updated exponential decay curves for wells ERM-2S, MW-104U, and MW-
112U. The decay curves plot the TCA concentrations detected in the well samples and from
which R2 values are calculated. The R2 value is the statistical measurement of how well the data
fit the projection, and ranges from 0.0 to 1.0 with the closer the value to 1.0, the greater the
confidence in the "goodness-to-fit" of the projection. The 2014 R2 value for ERM-2S has
improved from the 2009 value, 0.79 up from 0.67. If this rate of decrease continues then
extrapolation of TCA concentrations indicates they would decrease below the MCL in
approximately another 12-15 years, or 2026-2029 (the 2009 FYR indicated 2029-2029).
The 2014 R2 values for MW-104U and MW-112U remain close to zero, 0.003 and 0.073,
respectively, (0.003 and 0.055 in 2009), indicating that no statistically significant trend has
developed for TCA concentrations in these wells.
1,1,1 TCA in ERM-2S
1,000,000
100
10
1 _
0.00 5.00 10.00 15.00 20.00 25,00
Elapsed Time (Years)
Figure 3: Exponential Decay Curve for monitoring well ERM-2S
10
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10000
1,1,1 TCA in MW 104U
i
0 5 10 15 20 25
Elapsed Time (years)
Figure 4; Exponential Decay Curve for monitoring well MW-112U
11
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1,1,1 TCA in MW112U
1=- 1000
*<&
100
y = 7401.4e"ao32x
R2 = 0.0727
- Series 1
-Expon, (Seriesl)
10 15
Elapsed Time (years)
Figure 5: Exponential Decay Curve for monitoring well MW-112U
Seasonal Precipitation
Annual precipitation was above average between 2006 and 2008, slightly below average in 2009
and 2010, and above average in 2011 and 2013. However, the annual rate in 2012 was the third
lowest since 1994 and the lowest since 2002. In addition, the monthly precipitation for March
2013, 0.77 inches, was the lowest value for that month since moni toring of precipitation began in
1994. The increase in TCA in MW-104U and MW-112U during the April 2013 sampling round
may be in response to the low annual precipitation in 2012 and the low precipitation for March
2013. Similarly, the decrease in TCA concentrations in MW-104U and MW-112U in April 2014
may be in response to the increase in precipitation in the past year.
Site Inspection
EPA conducted a five-year review inspection on May 7, 2014, with representatives from Vishay-
Tansitor, Siemens Communications Systems, GZA GeoEnvironmental Inc. (GZA, the consultant
for Vishay-Tansitor and Siemens) and VTANR,
The inspection began with a meeting where the outlook of the facility was presented and then the
monitoring data and the long-term responsibilities were discussed. Following the meeting, the
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parties conducted a Site walkover, and located and inspected the monitoring wells. After the Site
inspection, the EPA representative drove around the neighborhoods contiguous to the Site to
check for new homes and developments.
The Vishay-Tansitor property, as noted above, is an operating manufacturing facility and has
been since 1956. The property is accessed through two entrances from Route 7. The property is
not fenced along Route 7 or along the property boundary. There remains a fence around the
former Disposal Area and another one around the Fire Pond. Beyond the buildings and parking
areas, the grounds are maintained as mowed lawns. Farther to the back, near the base of
Whipstock Hill, the property is wooded. The property on the south side of Route 7 is a wetland.
On the day of the Site inspection for this five-year review, there was no indication of any
disturbance of the grounds or any excavation within the TI Zone. The monitoring wells appeared
to be in acceptable condition with no indication of frost displacement and all riser caps were
secured.
The roads in the vicinity of the Site were driven to check for new development/new use. The
area remains predominantly rural residential interspersed with agricultural properties. There did
not appear to be any changes on Pleasant Valley Road to the southeast. During the 2004 and
2009 Site inspections of this 1.2 mile road there were sixteen houses, three Christmas tree farms,
one small corn field, and one motel with a few separate cottages. The same number of homes,
tree farms, fields and motel were observed on the 2014 inspection. On Route 7 itself, a
motorcycle shop and a farm produce store are located east of the Site, and a motel with a few
units and a farm are west of the Site. All of these have been present for many years; the motel
and farm dating back at least to the beginning of the RI negotiations in 1990. These properties
appeared to remain unchanged in 2014 other than the produce store which may be out of
business.
Houran Road leads off from Route 7, east of the Site and winds past the Site to the north. It also
is predominantly rural residential interspersed with agricultural properties. No new homes were
noted.
The New York state line is approximately a half mile west of the Site. No land use changes in
this area were noted during the 2014 inspection.
Interviews
During the FYR process, interviews were conducted with parties impacted by the Site, including
the current landowners, and regulatory agencies involved in Site activities or aware of the Site.
The purpose of the interviews was to document any perceived problems or successes with the
remedy that has been implemented to date. Interviews were conducted during the Site inspection
and on visits to Bennington Town Hall. The interviews are summarized below.
Representatives of the Settling Defendants noted the orders of magnitude decrease in
concentrations at ERM-2S, the overall decreasing concentrations within the plume, and the
consistency of the groundwater flow conditions with discharge of the plume into the Fire Pond.
Accordingly, they proposed changes in the groundwater monitoring program and VTANR and
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EPA were receptive to these changes. There was acknowledgement of the indefinite requirement
for five-year reviews while hopeful that someday that requirement would be lifted.
Michael Smith has been VTANR's project manager since 1993 and the lead agency
representative since December 1999 when VTANR assumed that responsibility. He was pleased
with the cooperation of the parties involved and the adjustments made to the long-term
monitoring program. He noted the overall decrease in concentrations which affirmed the Site
Conceptual Model.
Reviews of town services and records were done on September 11, 2014. According to staff in
the Town Of Bennington Tax Assessor's office, there has been no additional homes or
businesses built in the area surrounding Vishay-Tansitor in the past five years.
The Rural Conservation District zoning for the Site and surrounding area remains unchanged
since the 2009 FYR. The Town of Bennington Land Use & Development Regulations, adopted
February 23, 2004, and last amended June 12, 2006, defines the purpose of the Rural
Conservation District as "to preserve the rural character, scenic landscape and natural resources
of the area while accommodating low density residential development in a manner that avoids
the need for public water supply and public sewer systems." Vishay-Tansitor's industrial use of
the Site represents a grandfathered non-conforming use under the zoning regulations.
Similarly, staff in the Water Resources and Waste Management Department affirmed that there
has been no extension of either water or sewerage services in the area in the past five years.
Properties in the vicinity of the Site have individual water wells and septic systems.
The Bennington Free Library serves as the repository for the Site's 1995 Administrative Record.
It and subsequent records (the 2004 and 2009 FYRs) were located in the reference section of the
library. According to the reference librarian who began working there four years ago, there have
only been a couple requests in that time to review the Site records.
IV. TECHNICAL ASSESSMENT
Question A: Is the remedy functioning as intended by the decision documents?
Yes.
Remedial action performance. Two of the three Remedial Action Objectives (RAOs) specified
in the 1995 ROD have been achieved (EPA determined the third to be technically impracticable).
The threat posed to human health through exposure to groundwater is being prevented by
institutional controls. An Environmental Easement and Declaration of Restrictive Covenants are
recorded on the property deed. The Settling Defendants certify annually that there has been
compliance with the institutional controls. No excavation or disturbance of the soils within the
TI Zone has occurred. The use of the Site has not changed since the 1995 ROD.
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Operations and Maintenance. Neither the ROD nor Consent Decree specified any Operation and
Maintenance tasks. With the recording of the Environmental Easement and Declaration of
Restrictive Covenants in July 1999, the remedial action was determined to be complete per
EPA's guidance. The monitoring wells are maintained as part of regular grounds maintenance
for the facility.
Opportunities for Optimization. Based on the extensive data collected since 1994 and trends in
water quality, the number and frequency of monitoring locations have been reduced three times
and further modifications proposed in June 2014 have been approved by VTANR and EPA.
Given the stability of the groundwater monitoring data, the submittal of monitoring reports can
also be reduced to annual.
Indicators of Remedy Problems. There are no indicators of remedy problems. Vishay-Tansitor
makes repairs to the monitoring wells as needed.
Implementation of Institutional Controls and Other Measures. The environmental easement to
the State of Vermont and the restrictive covenants were recorded on the property deed on July
30, 1999. Vishay-Tansitor continues to certify annually that the restrictions have been
maintained and not violated, including the restraints on the facility's production well and a
prohibition on excavation within the TI Zone without agency approval.
Question B: Are the exposure assumptions, toxicity data, cleanup levels, and RAOs used at the
time of the remedy selection still valid?
No. Changes have occurred since the remedy was selected but the changes do not affect the
protectiveness of the remedy.
Changes in Standards and TBCs. There have been no changes in the chemical-specific ARARs
(MCLs or VT PGQSs) nor any location or action-specific ARARs. ARARs identified in the
1995 ROD were included in the 2009 FYR.
Changes in Exposure Pathways. No new exposure pathways were identified as part of this FYR.
Changes in Toxicity and Other Contaminant Characteristics. In 2010 and 2013, EPA updated
toxicity values for 1,4-dioxane and in 2011 and 2012, EPA updated the toxicity values of TCE
and PCE, respectively. Except for PCE which is found to be less toxic for cancer health effects,
the new toxicity assessments for 1,4-dioxane, TCE and PCE find these contaminants more toxic
for both cancer and non-cancer health effects (non-cancer only for PCE). Although an MCL has
not been established for 1,4-dioxane, MCLs for TCE and PCE have not been changed.
A review of EPA's Integrated Risk Information System did not indicate changes in toxicity
values since the 2009 FYR for TCA and DCE, the primary COCs identified in the 1995 ROD.
TCA was updated in 2007 and DCE in 2002. Additionally, vinyl chloride was last updated in
2000 and DC A in 1990. MCLs for TCA, DCE, and vinyl chloride have also not been changed
since the 2009 FYR.
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Changes in Risk Assessment Methods. In 2014, EPA finalized a Directive to update standard
default exposure factors and frequently asked questions associated with these updates.
http://www.epa.gov/oswer/riskassessment/superfund_hh_exposure.htm (items # 22 and #23 of
this web link). Many of these exposure factors differ from those used in the risk assessment for
the 1995 ROD. These changes in general would result in a slight decrease of the risk estimates
for most chemicals.
Although calculated risks from potential exposure pathways at the Site may differ from those
previously estimated in the ROD, higher for some contaminants and lower for a few others, the
revised methodologies themselves (EPA, 2005, 2009, 2011, 2013, 2014a, 2014b) are not
expected to affect the protectiveness of the remedy because exposure has been prevented by
implementation of the institutional controls.
Expected Progress Towards Meeting RAOs. The 1995 ROD set three RAOs. Two have been
met: prevent exposure to contaminated groundwater, and monitor to ensure that groundwater
contamination does not migrate beyond its 1995 extent. The third RAO, to restore the
groundwater if technically practicable, has not been achieved. EPA determined in the 1995
ROD that it was technically impracticable to restore the groundwater.
Question C: Has any other information come to light that could call into question the
protectiveness of the remedy?
No.
No other information has been discovered that would call into question the protectiveness of the
remedy.
Technical Assessment Summary
Based on the data reviewed, observations from the site inspection, and interviews, the remedy is
functioning as intended by the ROD. The institutional controls have been implemented and are
certified annually to be in compliance. The groundwater monitoring has demonstrated that
contaminants are not migrating to areas beyond the TI Zone or offsite. Therefore, the remedy is
functioning as designed and remains protective of human health and the environment.
Groundwater monitoring continues and maintenance of the monitoring wells is performed as
necessary.
The primary ARARs for groundwater at the TI Zone boundary are the MCLs and the VT
PGQSs. These continue to be met not only at the TI Zone boundary but also on the downgradient
side of the Fire Pond, consistent with the Site Conceptual Model. Groundwater contamination
levels within the TI Zone upgradient of the Fire Pond are generally decreasing.
Changes in the toxicity values for 1,4-dioxane, TCE, and PCE do not affect the protectiveness of
the remedy because exposure to the groundwater is prevented by institutional controls and
geologic and hydrologic factors prevent the plume from expanding beyond the extent
characterized in the 1995 ROD.
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Land use at the Site and surrounding properties have not changed and are not expected to
change, and there are no additional routes of exposure.
V. ISSUES/RECOMMENDATIONS AND FOLLOW-UP ACTIONS
This five-year review did not identify any current issues and no recommendations or follow-up
actions are made.
VI. PROTECTIVENESS STATEMENT
Protectiveness Statement: The site-wide remedy is protective of human health and the environment.
Institutional controls have been recorded. The institutional controls have prevented exposure to Site
groundwater, thereby ensuring the Site remains protective of human health. In addition, the State of
Vermont reclassified the groundwater beneath the Tl Zone to non-potable use only. Ongoing
monitoring demonstrates that the plume is stable and not migrating.
VII. NEXT REVIEW
The next five-year review report for the Tansitor Electronics Inc. Superfund Site is
required five years from the signature date of this review.
Pro tectiveness Deter m in a tion:
Protective
Addendum Due Date (if applicable):
Not Applicable
Click here to enter a date.
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APPENDIX A - EXISTING SITE INFORMATION
A. SITE CHRONOLOGY
EVENT
DATE
Property occupied by a farm, then a trucking company that had a two-bay garage
building.
Pre-1956
Beginning in 1956, various owners have used the Site as a manufacturing facility for
electronic capacitors.
1956 - current
Vishay-Tansitor Electronics, Inc. (formerly Tansitor Electronics, Inc., hereafter
" Vishay-Tansitor") notifies EPA that organic solvents and acids had been disposed of
onsite between 1956 and 1979.
May 1981
Subsequent to the notification, VTANR performed site inspections and requested that
Vishay-Tansitor initiate removal activities and implement a soil sampling and
analysis program in the Disposal Area.
1983 - 1987
VOCs were detected in overburden groundwater between the Disposal Area and the
Fire Pond. VOCs also were detected in surface water samples from the on-site
intermittent stream and the perennial stream south of Route 9.
1988
EPA placed the Site on the National Priorities List.
October 4, 1989
EPA notified seven parties, the current and former owners of the Site, of their
potential liability with respect to the Site.
March 1989 to May
1990
Two PRPs (Vishay-Tansitor and Siemens Communication Systems, Inc.) (hereafter,
the "Settling PRPs") enter into Administrative Order by Consent (AOC) with EPA
and under EPA oversight commenced an RI/FS for the Site.
September 12, 1990
VTANR issued a Groundwater Reclassification Order in response to a Vishay-
Tansitor petition. This Order changed the classification from Class III to Class IV
for the groundwater beneath the TI Zone.
November 23, 1993
EPA issued a ROD with State concurrence describing the remedial action to be
implemented at the Site. The ROD included a technical impracticability waiver for
MCLs for a ten acre area of the Site
September 29, 1995
ROD Contingencies #1 and #4 triggered for MW-104M and MW-112M
October 1998
U.S. District Court enters Consent Decree, under which Settling PRPs agree to
perform the remedy
March 24, 1999
Restrictive Covenant recorded on Vishay-Tansitor deed at the Bennington County
Registry of Deeds
July 30, 1999
Deletion of the Site from NPL recorded in the Federal Register
September 29, 1999
VTANR accepts lead agency responsibility from EPA
December 3, 1999
ROD Contingency #5 triggered for MW-112M
January 2002
First Five-Year Review
September 2004
Long-term monitoring continues
2004 - current
Second Five-Year Review
September 2009
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B. BACKGROUND
Physical Characteristics
The Site consists of approximately 44 acres of land on West Road (Route 9) in the Town of
Bennington, Vermont, and is approximately 3.5 miles west of Bennington Center (see Figure 1,
top). Most of the Site (37.6 acres) is located to the north of Route 9, with the remainder of the
Site (6.6 acres) located to the south of Route 9. The portion of the Site located to the south of
Route 9 consists of forested wetlands and there are also wetlands on the property north of Route
9.
The general topography surrounding the Site consists of rolling hills oriented north-south
between the Green and Taconic Mountains. The Site lies at the southeastern portion of the base
of Whipstock Hill. Elevations at the Site and close vicinity generally decrease to the south.
Groundwater flow direction at the Site generally mimics surface contours.
Surficial runoff from the Site (storm water, snow melt and from groundwater seeps) drains into
the Fire Pond, an intermittent stream located onsite, and the facility storm drain system, and
ultimately into the wetland area south of Route 9. An unnamed east-west flowing perennial
stream, located south of Route 9, enters the Site from the east and flows through these wetlands
into Browns Brook, a Class B surface water body located about one-half mile offsite. Brown
Brook flows into the Hoosic River another three to four miles downstream.
Glacial activity has greatly influenced the geology and hydrogeology in the vicinity of the Site.
To the north is the Whipstock Hill drumlin, which controls the surface water and groundwater
flow directions across and beneath the Site. Underlying the Site is approximately 180 feet of
glacial till, a mixture of dense deposits of silty clay, clayey silt, silt, and fine to coarse sand and
gravel.
The till can be further divided into three units: ablation till, present from the ground surface to
about 35 feet; a silty sand basal till about 15 feet thick; and a silty clay basal till approximately
130 feet thick. The till overlies bedrock which is comprised of variably fractured limestone
under the southern portion of the Site and phyllite under the northern portion.
Land and Resource Use
The Site is located in an area zoned Rural Conservation with a commercial corridor overlay
along Route 9. As a manufacturing facility, Vishay-Tansitor's industrial use of the Site
represents a grandfathered non-conforming use under the zoning regulations. The Site is
bounded to the north by privately owned woodland; to the east by Houran Road and a
commercial property; to the south by wetlands; and to the west by agricultural/residential areas.
Pleasant Valley School is located approximately 1,200 feet east and topographically upgradient
of the Site.
Since issuance of the ROD and through the date of this five-year review, Vishay-Tansitor has
continued to manufacture electronic capacitors at the Site. Major site features include Vishay-
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Tansitor's operating manufacturing/office building, an Etch House, a man-made pond (known as
the Fire Pond), parking areas, a Solid Waste Disposal Area, a Disposal Area, a Concrete Pad
Area, and a Borrow Area (see Figure 1, bottom). As discussed below, there have been no
changes in land use at the Site or the surrounding community since issuance of the ROD.
Potable water supplies for the surrounding properties, as well as the water supply on the Site, are
provided by private bedrock wells. Prior to 1993, the aquifer beneath and in the vicinity of the
Site was classified by VTANR as Class III, which is defined as suitable as a source of water for
individual domestic drinking water supply, irrigation, agricultural use, and general industrial and
commercial use. However, in response to a petition from Vishay-Tansitor that was based on the
data obtained during the RI, on November 23, 1993, VTANR issued a Groundwater
Reclassification Order that reclassified groundwater beneath a 9.6 acre area of the Site, where
groundwater contamination was detected, from Class III to Class IV. Class IV groundwater is
defined as not suitable as a source of potable water but suitable for some agricultural, industrial
and commercial use. This Reclassification Order was modified on March 10, 1994 to allow for a
trained Vishay-Tansitor employee, approved by VTANR, to conduct and report the monitoring.
Subsequent to the issuance of the ROD and through the date of this five-year review, sanitary
waste water from the Vishay-Tansitor facility has been disposed of into the Town of Bennington
public sewer system.
Also subsequent to the issuance of the ROD, the facility on its own discontinued use of its
production well as its drinking water source. The facility relies on bottled water for drinking
water, but continues to use its production well for process water in its manufacturing of electrical
components.
History of Contamination
The record indicates that prior to 1956 a trucking company occupied the property and had a two-
bay garage building. Prior to the trucking company operation, the property was farmland.
Since 1956, various owners have used the Site as a manufacturing facility for electronic
capacitors. In May 1981, in compliance with Section 103(c) of the Comprehensive
Environmental Response, Compensation, and Liability Act, 42 U.S.C. § 9603(c), Vishay-
Tansitor notified EPA that organic solvents and acids had been disposed of on-site between 1956
and 1979. Over that period, the estimated equivalent of 117 drums of process waste were
disposed of in a 900-square foot area to the north of the Vishay-Tansitor manufacturing building
(referred to throughout this five-year review as the "Disposal Area"). During the period of 1975-
1979, the process waste disposed in the Disposal Area included 1,1,1-TCA which is the
predominant VOC present in the groundwater. Vishay-Tansitor also reported that some waste
detergents and dilute acid solutions may have been discharged into the two leach fields (now out
of service with the extension and connection to the public sanitary sewer system in 2001) or
directly into the intermittent stream north of its manufacturing building. Finally, Vishay-
Tansitor reported that waste methanol had been burned periodically on the Concrete Pad.
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Initial Response
Following the 1981 notification to EPA of hazardous waste disposal activities, VTANR
instructed Vishay-Tansitor to restrict access to the Fire Pond and disposal areas; define the areal
and vertical extent of contaminated soil at the Disposal Area; remove the contaminated soil for
proper disposal at a certified hazardous waste facility; design and implement an evaluation and
monitoring program to determine the magnitude and extent of contamination resulting from the
Site; and determine potential remedial actions.
In 1988, Vishay-Tansitor hired a contractor to perform the site investigation requested by
VTANR. During this investigation, VOCs were detected in overburden groundwater samples
from three monitoring wells located between the Disposal Area and the Fire Pond. No VOCs
were detected in one monitoring well upgradient of the Disposal Area or in two monitoring wells
south of the Fire Pond. However, surface water samples from the on-site intermittent stream and
the perennial stream south of Route 9 did reveal VOC contamination.
Basis for Taking Action
Pursuant to an Administrative Order by Consent effective September 12, 1990, the Settling PRPs
commenced a Remedial Investigation and Feasibility Study (RI/FS) for the Site under EPA
oversight. The Settling PRPs completed and EPA issued an RI Report on June 10, 1994, and the
Settling PRPs completed and EPA issued an FS Report on February 13, 1995.
The RI found that there were two distinct source areas of VOCs detected at the Site, the Disposal
Area and Concrete Pad Area. Areal extent of the Disposal Area is approximately 900 square
feet; areal extent of the Concrete Pad Area is approximately 400 square feet.
Disposal Area soils contained low levels of VOCs, and elevated levels of silver and nickel. The
highest concentrations of VOCs were found in soils at a depth of seven to eight feet below the
ground surface. No dense non-aqueous phase liquids (DNAPLs) were found in the soils in this
area, and the VOC concentrations found in the unsaturated soils did not suggest the presence of
DNAPLs.
Concrete Pad Area soils also contained low levels of VOCs. The highest concentrations of
VOCs were detected in soils at a depth of 10 to 15 feet below the ground surface. No evidence
of DNAPLs was observed in these soils.
Semi-volatile organics were sporadically detected in samples from the Site. The occurrence of
these compounds was attributed to the combustion by-products of fossil fuels and runoff from
road surfaces. These compounds did not appear to be related to past or current production or
wastewater disposal processes at the facility.
The RI identified two significant plumes or zones of VOC contamination in shallow
groundwater. The first plume originates from the Disposal Area and extends to the Fire Pond,
impacting an area approximately 170 feet by 260 feet, or slightly more than an acre. Based on
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soil gas analyses and groundwater analytical data, it appeared that the plume did not exceed the
width of the Fire Pond.
Contaminants detected throughout the Disposal Area plume above federal drinking water
standards, Maximum Contaminant Levels (MCLs), included 1,1,1-TCA and 1,1-
dichloroethylene (1,1-DCE). The highest concentration of 1,1,1-TCA detected was 470,000
parts per billion (ppb) (MCL of 200 ppb); the highest concentration of 1,1-DCE detected was
3,800 ppb (MCL of 7 ppb). Unlike the soils, with the 1,1,1-TCA concentration well above the
solubility limit associated with DNAPL, this suggested that groundwater contamination may be
present in DNAPL form. These concentrations were both detected in well ERM-2S.
The other significant plume originated from under the Concrete Pad Area, impacting an area
approximately 60 feet by 240 feet, or about one-third of an acre. VOCs were detected above
their MCLs at sampling location MW-108U. The highest concentrations detected were as
follows: 1,1,1-TCA, 2000 ppb; 1,1-DCE, 180 ppb; trichloroethylene, 19 ppb (MCL of 5 ppb);
and tetrachloroethylene, 20 ppb (MCL of 5 ppb).
On February 27, 1995, EPA published notice of the completion of the FS and the proposed plan
for remedial action on February 27, 1995, in the Bennington Banner, the major local newspaper
of general circulation. EPA provided an opportunity for written and oral comments from the
public on the proposed plan for remedial action.
On September 29, 1995, with concurrence from VTANR, the ROD was signed. The ROD set
forth a limited remedy for the Site that combined institutional controls, groundwater (and surface
water if necessary) monitoring with contingencies for further investigation or further action, and
five-year reviews. The primary contaminants of concern (COCs) affecting on-site soil,
groundwater, surface water and/or sediment were determined to be VOCs.
C. REMEDIAL ACTIONS
Remedy Selection
The September 29, 1995 ROD for the Site specified a multi-component remedy to address
groundwater contamination. Based on the RI, remedial action objectives were identified for the
Site:
Eliminate or minimize the threat posed to human health and the environment by
preventing exposure to groundwater contaminants by any individual who may use the
groundwater within the area of the shallow plumes or within an area where groundwater
could become contaminated as a result of pumping activities;
Prevent the migration of groundwater contamination beyond its current extent, or to
monitor the groundwater to ensure that contamination is not migrating beyond its current
extent; and
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If technically practicable, to restore contaminated groundwater to drinking water
standards, and to a level that is protective of human health and the environment.
The remedy selected in the ROD specified:
Institutional controls to prevent the use of contaminated groundwater and to inform future
purchasers of property of the groundwater restrictions associated with the property;
Long-term monitoring of site groundwater on a regular basis to evaluate changes in site
conditions over time;
Contingencies for future additional investigation or further action should the long-term
monitoring reveal that contaminants have migrated beyond their vertical or horizontal
extent at the time of the ROD; and
Review of the Site every five years to ensure that the remedy remains protective of
human health and the environment.
In addition to these components of the remedy, EPA waived chemical-specific ARARs for a 9.6-
acre portion of the Site. This area, designated as the Technical Impracticability Zone (TI Zone),
has the same surficial dimensions as the Class IV zone established in the November 1993
Vermont Groundwater Reclassification Order (and modified in February 1994). Unlike the
Class IV area, the TI Zone also has a vertical dimension and that extends to the bedrock surface.
As more fully explained in the ROD, the site geology and hydrology that limited the spreading of
the contamination also made restoration through an engineering approach impracticable, and thus
EPA determined that it would be technically impracticable to attain groundwater standards
within a reasonable period of time. (See Figure 1 in the 2014 FYR text for the TI Zone/Class IV
boundary)
Institutional controls were to be established to prevent the use of groundwater impacted by the
Site and to inform future purchasers of the property of the groundwater restrictions associated
with the property. These institutional controls were to consist of deed restrictions to provide
permanent, enforceable restrictions on the use of groundwater at the Site. The Vermont
Groundwater Reclassification Order would also serve to restrict use of the Site groundwater.
The deed restrictions were to provide the following:
(1) No water supply well was to be installed in either the overburden soils or bedrock within the
area designated as a Class IV Groundwater Area by the State of Vermont (marked generally by
MW-107U in the northeast, the Eastern Leach Field in the southeast, MW109U in the
southwest, and the Water Reservoir in the northwest).
(2) No water supply well was to be installed in either the overburden soils or bedrock within the
Class III Area on the Vishay-Tansitor property without prior EPA approval. At the time of the
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ROD (and continuing to this day), Vishay-Tansitor's operating facility was drawing its process
water from a bedrock well located west of the Class IV area. EPA acknowledged that either the
current owner or potential future owners of the property may need or desire another source of
water outside the Class IV Area at some time in the future because of possible failure of the
existing well or development on other parts of the property. Because the addition of a new well,
however, could cause contaminants to migrate or otherwise affect the contaminant plumes, EPA
would require for any proposal for a new well a demonstration that such an action would not
induce movement of the contaminants into uncontaminated areas. This demonstration would
include, at a minimum, pump tests and laboratory analysis for VOCs. Should the demonstration
indicate the proposed well would have an adverse effect on the plume, as determined by EPA, it
would not be installed. It was (and is) not the intent of EPA to preclude the use of other areas of
the Site with this requirement, rather it was (and is) to ensure that the institutional controls and
monitoring remain protective and that further migration is prevented.
In the event that new water supply wells are installed with EPA approval in the future, additional
monitoring positions located between the contaminant plume and the new water supply well may
be required. These positions would be used to monitor for possible changes in on-site
groundwater flow patterns (as it affects contaminant distribution). The water level monitoring
program would be accomplished through the periodic use of continuous recorders on selected
monitoring wells during seasonal low water periods.
(3) The existing production well located at the Tansitor Site would not be used to extract more
than 20,000 gallons of water per day, without prior EPA approval, as increased use of
groundwater at and in the vicinity of the plumes could adversely affect the plumes. Therefore, if
use and pumping of the current well were to be proposed beyond the level of the RI pump test,
which was approximately 20,000 gallons per day, a determination would be made by EPA as to
the potential impact on the plumes.
(4) The TI Zone would be used solely for industrial and commercial purposes, unless other uses
of the TI Zone were approved by EPA.
(5) No excavation or construction activities that would disturb the soil within the TI Zone would
be undertaken without EPA approval.
(6) All of the above-listed restrictions were to remain in effect as long as contaminated
groundwater is present at the Site at levels in excess of federal drinking water standards, and at
levels that are not protective of human health and the environment.
With respect to the State or local requirements, as noted above, the State of Vermont reclassified
the groundwater in the area of the contaminated plumes from Class III to Class IV groundwater.
Class IV groundwater under the state classification system is considered not suitable as a source
of potable water but suitable for some agricultural, industrial, or commercial use. In addition,
the Reclassification Order stated that a review of the monitoring data be performed by VTANR
after five years of monitoring, and possibly thereafter for successive five-year intervals. While
VTANR took this action independently of EPA, EPA believed that the reclassification, together
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with institutional controls described above, would effectively prevent future exposure to
contaminated groundwater at the Tansitor Site.
The ROD-specified monitoring program was to be implemented to demonstrate that the
conceptual model presented was correct, i.e., that the contaminants are not migrating horizontally
beyond the Fire Pond or vertically toward the bedrock. The monitoring was also be used to
evaluate the overall protectiveness of the remedy. The groundwater monitoring program was to
include sampling and analytical methods that were appropriate for groundwater sampling and
that accurately measure hazardous constituents in the samples. Monitoring was to be performed
in wells located at and around the property boundary and within the interior of the Site to
monitor the levels, distribution, and migration of VOCs, silver, and lead. Monitoring was also to
include water level measurements.
Remedy Implementation
Following the entry of the Consent Decree in March 1999, the Settling PRPs submitted a draft
Environmental Protection Easement and Declaration of Restrictive Covenants to EPA and
VTANR. This document was approved by EPA and then recorded July 30, 1999 on the property
deed at the Town Clerk's Office for the Town of Bennington, Bennington County.
Groundwater Monitoring
The ROD required the implementation of a semi-annual groundwater monitoring program for at
least five years. If the action levels established by the ROD were exceeded, the ROD required
further evaluation of the remedial action via contingencies described in the ROD. The ROD
established a three-dimensional Technical Impracticability Zone where drinking water standards
were waived. Outside the TI Zone, drinking water standards were set as the action levels, or
standards, for all groundwater contaminants.
The following detailed summary of the monitoring wells has been entirely copied from the 2009
FYR to provide background for the data review discussion in Section 3 of the text above. (See
Figure 1 in the 2014 FYR text for monitoring well locations)
MW-101M/R wells were installed during the 1991 Phase 1A RI to the northeast of the Disposal
Area. These wells are screened in the sandy basal till and bedrock respectively. They are
outside the TI Zone that was established in the September 1995 ROD. Vertical gradient is
typically downward. Because no contaminants had ever been detected in either of these wells, as
part of the monitoring adjustment made after the 2004 Five-Year Review, VTANR as the lead
agency for the Site approved the removal of these wells from the sampling program.
ERM-2S was installed prior to the RI in response to the request from VTANR for an
investigation of site conditions and is located just off the southwest corner of the Disposal Area.
It is screened in the shallow ablation till. From the beginning this has been the most
contaminated monitoring well, with 1,1,1-TCA concentrations initially as high as 470,000 |ig/L.
The 2004 FYR reported that concentrations of all contaminants at ERM-2S had been decreasing
since 1998 and were the rates to remain constant, the 1,1,1-TCA MCL could be approached in
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the next 20-30 years. An update of the exponential decay curve (see Figure 3A) projects a
similar extrapolation where 1,1,1-TCA concentrations at ERM-2S would decrease below the
MCL in approximately another 20 to 25 years. However, this extrapolation should be viewed as
a rough estimate for the following reasons. The decreasing trend appears to continue in the fall
data, yet the spring data reveals little change in the past five years. Second, the R2 value, the
statistical measurement of how well the data fit the projection, is 0.67 (the range for R2 is from
0.0 to 1.0 and the closer to 1.0, the greater the confidence in the "goodness-to-fit") suggesting
this extrapolation should be viewed with caution. And further, this extrapolation assumes a
continuous rate of decline whereas historically these rates slow down as concentrations decrease
and become asymptotic with little decline (see Figure 3B). Nonetheless, while the precision
regarding the rate of decrease is not certain, overall the concentrations have been consistently
decreasing and thus in 2009 VT ANTR approved the change in sampling frequency from semi-
annual (spring and fall) to annual (spring).
MW-112U/M wells were installed during the 1992 Phase IB RI downgradient of MW-101 and
the southeastern corner of the Disposal Area. MW-112U is screened in the shallow ablation till
and MW-112M is screened at the top of the silty clay section of the basal till. Vertical gradient
is typically downward toward MW-112M. MW-112U was not originally part of the long-term
monitoring, but was added to the program in January 2000. MW-112M triggered Contingency
#4 and thus its sampling frequency was increased to quarterly in 1999. The sampling frequency
for both wells was reduced to semi-annual in 2005 as there was no significant difference in
concentrations from one sampling event to the next. The sampling frequency for both wells was
further modified to annual (spring) by VTANR in 2009.
The 2004 FYR reported that 1,1,1-TCA concentrations in MW-112U were decreasing at a
similar rate as ERM-2S and projected approaching the MCL in 15-20 years. The 1,1,1-TCA
concentrations have continued to decrease since the 2004 FYR but at a slower rate than at ERM-
2S. This is not unreasonable as MW-112U is farther from the original source area. The updated
exponential decay curve suggests 1,1,1-TCA might attain the MCL in the next 75 to 80 years.
That the projection has changed is not surprising given the relative location of MW-112U in the
plume; further it is noted that the R2 value for this extrapolation is 0.05, indicating that no
definitive trend has developed.
The 2004 FYR indicated that 1,1,1-TCA and 1,1-DCE concentrations at MW-112M had been
increasing from 1994 through 2004. Since then, concentrations for both compounds appear to
have stabilized with 1,1,1-TCA and 1,1-DCE concentrations about 600 and 150 |ig/L,
respectively.
MW-104U/M wells were installed during the 1991 Phase 1A RI downgradient of the Disposal
Area and just upgradient of the Fire Pond. These wells are screened in the shallow ablation till
and sandy basal till, respectively. Vertical gradient is typically upward toward MW-104U as the
groundwater discharges to the Fire Pond and the ground surface at this location is often saturated
with MW-104M showing flowing artesian conditions. MW-104M triggered Contingency #4 and
thus its sampling frequency was increased to quarterly in 1999. The sampling frequency for both
wells was reduced to semi-annual in 2005 as there was no significant difference in
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concentrations from one sampling event to the next. The sampling frequency for both wells was
further modified to annual (spring) by VTANR in 2009.
The 2004 FYR reported that 1,1,1-TCA, 1,1-DCE and 1,1-DCA concentrations at MW-104U
had fluctuated since sampling began, generally between 500 - 1200 |ig/L, 5-25 |ig/L, and 100 -
450 |ig/L, respectively. Data collected from October 2004 through spring 2008 are consistent
with the previous data, continuing to fluctuate. This is expected since it is the farthest away from
the original source area. As the plume migrates from the source area, concentrations at this well
will likely remain consistent for several years and it is likely that concentrations at this well have
not yet peaked. The updated exponential decay curve reflects this with an R2 value of 0.003,
statistically indicating there is no trend in the data.
Concentrations in MW-104M had shown a similar pattern during the period covered in the 2004
FYR, but in the years following that review, concentrations of 1,1,-TCA and 1,1-DCE have
decreased such that both compounds are now meeting their respective MCL.
ERM-4S was installed prior to the RI in response to the request from VTANR for an
investigation of site conditions and is located between the manufacturing building and the Fire
Pond. It is screened in the shallow ablation till. It had been sampled semi-annually and no
contaminants above 2 |ig/L have ever been detected in this well. Consequently, in 2009 VTANR
agreed to the remove this well from the Long-Term Monitoring program.
MW-105M was installed during the Phase 1A RI adjacent to ERM-4S to determine whether the
Disposal Area plume was moving past the Fire Pond to the west. It is screened at the bottom of
the sandy basal till. Since 2001, 1,1,1-TCA has been detected at very low concentrations, 1J to 5
|ig/L. Since the 2004 FYR, concentrations of 1,1,1-TCA and 1,1-DCE have continued to
marginally increase, up to 11 and 4 |ig/L, respectively. The sampling frequency continues to be
quarterly.
MW-103M/R wells were installed during the Phase 1A RI downgradient of the Fire Pond. These
were screened in the sandy basal till and bedrock, respectively. These wells exhibit an upward
gradient, such that the groundwater flow is upward toward the ground surface and MW-103R
typically is under flowing artesian conditions where groundwater flows out of the well onto the
land surface. No contaminants have ever been detected in these wells above the method
detection levels. The sampling frequency of these wells has been annual (spring) since
September 2005.
ERM-5S/D wells were installed prior to the RI in response to the request from VTANR for an
investigation of site conditions and are located near the southeastern corner of the Fire Pond.
These wells exhibit an upward gradient, with ERM-5D often under flowing artesian conditions.
No contaminants have ever been detected in these wells above the method detection levels. The
sampling frequency of these wells has been annual (spring) since September 2005.
MW-108U was installed during the Phase 1A RI to assess the potential plume emanating from
the Concrete Pad Area. It is located adjacent to the northeast corner of the manufacturing
building and is screened in the shallow ablation till. In addition to 1,1,1-TCA and 1,1-DCE,
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tetrachloroethylene (PCE), trichloroethylene (TCE), 1,1-DCA, and 1,2-DCE are also present in
the Concrete Pad Area plume. The 2004 FYR reported that with the exception of 1,1-DCA, all
of the other compounds had similar decreasing trends, apparently peaking in the 1997 to 1999
time interval. Data collected from October 2004 through spring 2008 exhibit continuing
decreasing trends with a five-fold decrease in 1,1,1-TCA and approximately two-fold decrease in
the other compounds, including 1,1-DCA. The sampling frequency for both wells was reduced
to semi-annual in 2009 as there has been no significant difference in concentrations from one
sampling event to the next.
MW-109U and MW-110U were installed during the Phase 1A RI in 1991 and are located in the
facility parking areas adjacent to Route 7. MW-109U is the most downgradient well within the
TI Zone and MW-110U is located 150' west of the southwestern corner of the TI Zone. Both are
screened in the ablation till. No contaminants have ever been detected in these wells above the
method detection levels, and their sampling frequency was decreased from semi-annual to annual
in September 2005. In 2009, VTANR modified the sampling frequency of MW-110U to once
every two years; MW-109U continues to be sampled annually.
MW-114U was installed in response to the October 1993 Groundwater Reclassification Order. It
is located on the south side of Route 7 (the southern boundary of the TI Zone is the north side of
Route 7) and it is screened in the shallow ablation till. No contaminants have ever been detected
in this well above the method detection levels and its sampling frequency was decreased from
semi-annual to annual in September 2005. In 2009, VTANR modified the sampling frequency of
MW-114U to once every two years.
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APPENDIX B - Additional Figures for Reference
FIGURE li SITE LOCUS VIEWS
Vishay-Tansitor Electronics Inc., Site, Bennington, Vermont. New York-Vermont boundary is a
half-mile to the west
Vishay-Tansitor Electronics Inc. Site, Bennington Vermont. Disposal Area was located at top of
photograph in wooded area north of dirt road. Concrete Pad Area was located between the dirt
road and the stand-alone building in the top center of the photograph.
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APPENDIX C
PRESS RELEASE ANNOUNCING FIVE-YEAR REVIEW
Newsroom
EPA Will Review 27 Superfund Site Clean Ups This Year
Release Date: 02/13/2014
Contact Information: Emily Zimmerman, 617-918-1037
Boston, Mass. - (February 13, 2014) - EPA will review site clean ups and remedies at 27
Superfund Sites across New England this year by doing routine Five-Year Reviews at each site.
EPA conducts evaluations every five years on previously-completed clean up and remediation
work performed at Superfund sites and Federal Facilities listed on the "National Priorities List"
(aka Superfund sites) to determine whether the implemented remedies at the sites continue to be
protective of human health and the environment. Further, five year review evaluations identify
any deficienci es to the previous work and, if called for, recommend action(s) necessary to
address them.
In addition to a careful evaluation of technical work at the sites, during the Five Year Review
process EPA also provides the public with an opportunity to evaluate preliminary findings and to
provide input on potential follow up activity that may be required following the review process.
The Superfund Sites at which EPA is performing Five Year Reviews over the following several
months include the following sites. Please note, the Web link provided after each site provides
detailed information on site status and past assessment and cleanup activity.
Connecticut
Linemaster, Woodstock, CT
http://www.epa. gov/regi on 1 / superfund/ si tes/li nemaster
Nutmeg Valley, Wolcott, CT
http://www.epa.gov/regionl/superfund/sites/nutmeg
Maine
Saco Tannery Waste Pits, Saco
http://www.epa. gov/regi on 1 /superfund/sites/sacotannery
Massachusetts
Nyanza Chemical Waste Dump, Ashland
http ://www. epa. gov/regi on 1 /superfund/si tes/n vanza
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Baird & McGuire, Holbrook
http://www.epa. gov/region 1 / superfund/ sites/baird
Hatheway & Patterson, Mansfield
http://www.epa. gov/region 1 / superfund/ sites/hatheway
Hocomonco Pond, Westborough
http://www.epa.eov/reeionl/superfimd/sites/hocomonco
Rose Disposal, Lanesborough
http://www.epa. eov/reeion 1 / superfund/ sites/ftrose
Silresim, Lowell
http://www.epa. eov/reeion 1 / superfund/ sites/silresim
W.R. Grace, Acton
http://www.epa. eov/reeion 1 / superfund/ sites/graceacton
Wells G&H, Woburn
http://www.epa. gov/region 1 / superfund/ sites/wellsgh
Norwood PCBs, Norwood
http://www.epa. gov/region 1 / superfund/sites/norwood
South Weymouth Naval, Weymouth, MA
http://www.epa. gov/region 1 / superfund/ sites/ swevmouth
New Hampshire
Ottati & Goss, Kingston
http://www.epa. gov/region 1 / superfund/ sites/og
Tinkham Garage, Londonderry
http://www.epa. gov/region 1 / superfund/ sites/tinkham
Sylvester, Hillsborough County
http://www.epa. gov/region 1 / superfund/ sites/Sylvester
Town Garage/Radio Beacon, Rockingham
http://www.epa. gov/region 1 /superfund/sites/town garage
New Hampshire Plating, Hillsborough County
http://www.epa. gov/region 1 / superfund/ sites/nhplating
Pease Air Force Base, Portsmouth, Newington and Greenland, NH
http://www.epa. gov/region 1 / superfund/ sites/pease
Rhode Island
Landfill Resource & Recovery, North Smithfield
http://www.epa. gov/region 1 / superfund/ sites/1 rr
Vermont
Elizabeth Mine, Strafford
http://www.epa. gov/region 1 / superfund/ sites/elizmine
Parker Sanitary Landfill, Lyndonville
http://www.epa. gov/region 1 / superfund/ sites/parker
Pownal, North Pownal
http://www.epa. gov/region 1 / superfund/ sites/pownal
Bennington Municipal Landfill, Bennington
http://www.epa. gov/region 1 / superfund/ sites/bennington
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BFI Sanitary Landfill, Rockingham
http://www.epa. gov/region 1 / superfund/ sites/bfi
Tansitor Electronics, Inc, Bennington County
http://www.epa. gov/region 1 / superfund/ sites/tan si tor
Pine Street Canal, Burlington
http://www.epa. gov/region 1 / superfund/ sites/pinestreet
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