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OTHhR:

Five-Year Review Report

Second Five-Year Review Report

for

The Town Garage/Radio Beacon Superfund Site

Town of Londonderry

Rockingham County, New Hampshire

March 2004

Prepared by:

The United States Environmental Protection Agency

Region 1, New England

Boston, Massachusetts

A EP

New Englan

A

d

Approved by: Date:

Susan Studlien, Director

Office of Site Remediation and Restoration

U.S. EPA, New England

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SDMS DocID 000201499
Table of Contents

Five Year Review Summary Form

I. Introduction 1

II. Site Chronology 2

III. Background 2

A. Physical Characteristics 2

B. Land and Resource Use 2

C. History of Contamination 3

D. Basis for Taking Action 3

IV. Remedial Actions 3

A. Remedy Selection 3

B. Remedy Implementation 3

C. System Operations/Operation and Maintenance (O&M) 4

V. Progress Since the Last Five-Year Review 4

VI. Five-Year Review Process 5

A. Administrative Components 5

B. Community Involvement 5

C. Document Review 5

D. Data Review 5

E. Site Inspection 6

F. Interviews 6

VII. Technical Assessment 6

A. Is the remedy functioning as intended by the decision documents? 6

B. Are the exposure assumptions, toxicity data, cleanup levels, and remedial

action objectives used at the time of remedy selection still valid? 6

C. Has any other information come to light that could call into question the

protectiveness of the remedy? 7

VIII. Issues 8

IX. Recommendations and Follow-up Actions 8

X. Protectiveness Statement 9

XI. Next Review 9
Attachment A

Documents Reviewed

Figures

Attachment B

Figure 1 - Site Map

Figures 2 through 14 - Concentration vs. Time Plots

Tables

Table 1 - Chronology of Site Events Page 2

Table 2 - ROD Ground Water Cleanup Goals and Results Page 4
Five-Year Review Summary Form

SITE IDENTIFICATION

Site name: Town Garage/Radio Beacon

EPA ID: NHD981063860

Region: 1 State: New Hampshire City/County: Londonderry/Rockingham

SITE STATUS

NPL status: /Final D Deleted D Other (specify).

Remediation status (choose all that apply): D Under Construction D Operating / Complete

Multiple OUs?* DYES /NO Construction completion date: September 30,1992

Has site been put into reuse? / YES D NO

REVIEW STATUS

Lead agency: / EPA D State D Tribe D Other Federal Agency

Author name: James DiLorenzo

Author title: Remedial Project Manager Author affiliation: U.S. EPA, Region 1

Review period: February 6, 2004, through March, 2004

Date(s) of site inspection: February 27, 2004

Type of review:

/ Post-SARA D Pre-SARA D NPL-Removal only

D Non-NPL Remedial Action Site D NPL State/Tribe-lead

D Regional Discretion

Review number: D 1 (first) / 2 (second) D 3 (third) D Other (specify)

Triggering action:

D Actual RA Onsite Construction at OU #_

D Construction Completion

D Other (specify)

D Actual RA Start at OU#

/ Previous Five-Year Review Report

Triggering action date;: March 31, 1999

Due date: March 31,2004
Five-Year Review Summary Form, cont'd.

Issues:

No issues were identified during this review.

Recommendations and Follow-up Actions:

Londonderry's consultant will continue to sample residential and monitoring wells. If the

results of sampling indicate that additional remedial actions are needed, options will be

evaluated and implemented which would protect the public health.

Londonderry's consultant will sample surface waters after all monitoring wells have

achieved cleanup levels.

The Groundwater Management Permit will remain in-place until all monitoring wells have

achieved cleanup levels.

Protectiveness Statement:

Because the remedial actions being implemented throughout the Town Garage/Radio

Beacon Superfund Site are protective, the site is protective of human health and the

environment.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review Report

I. Introduction

The purpose of a five-year review is to determine whether a remedy at a Superfund site is

protective of human health and the environment. The methods, findings and conclusions of

reviews is documented in five-year review reports. In addition, five-year review reports identify

issues found during the review, if any, and recommendations to address them.

The U.S. Environmental Protection Agency (EPA) New England must implement five-year

reviews consistent with the Comprehensive Environmental Response, Compensation, and

Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution Contingency

Plan (NCP). CERCLA Section 121(c) 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.

EPA 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 initiation of the selected remedial action.

EPA conducted this second five-year review of the remedial actions implemented at the Town

Garage/Radio Beacon Superfund Site, in Londonderry, New Hampshire. This is a policy review

since upon completion of the remedial action no hazardous substances will remain above levels

that allow for unlimited use and unrestricted exposure, but five or more years are required to

reach that point. The review was conducted from February through March, 2004. This report

documents the results of the review. The trigger for this review is the signature date of the initial

five-year review, March 31, 1999.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page 2

II. Site Chronology

Table 1 lists the chronology of events for the Town Garage/Radio Beacon Superfund Site.

Table 1: Chronology of Site Events

Date

1984

1988 - 1989

March 3 1,1989

September 30, 1992

September 30, 1992

September 30, 1996

August 1997

March 3 1,1 999

Event

Discovery of the problem

Provision of public water

Final listing on NPL

RI/FS completed

ROD signature

Unilateral Order issued to town of Londonderry to perform ground

water monitoring

Issuance of Groundwater Management Permit to town of

Londonderry

First five-year review report

III. Background

A. Physical Characteristics

The Town Garage/Radio Beacon Superfund Site is located north of Pillsbury Road near

the intersection of Pillsbury and High Range Roads in Londonderry, New Hampshire.

Much of the area is wooded with a wetland located between residential developments.

See Figure 1.

B. Land and Resource Use

The site encompasses two residential developments: twenty-three homes on Holton Circle

and thirteen homes on Saddleback Road; a wetland area; and the Londonderry town

garage area located on High Range Road.

All homes in the Saddleback Road subdivision are attached to a public water supply.

Several homes in the Holton Circle subdivision remain on private wells since they have a

long history of remaining unaffected by the groundwater contamination.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review. March 2004 Page 3

C. History of Contamination

The site was discovered in 1984 following a request to the State by residents of the

Holton Circle subdivision to sample their bedrock wells. Sampling results from the New

Hampshire Department of Environmental Services (NHDES) revealed the presence of

volatile organic compounds (VOCs) in several of the residential drinking water wells and

the nearby town garage well. The Site was added to the National Priorities List (NPL) on

March 31,1989.

D. Basis for Taking Action

The major contaminants detected in ground water included 1,1 dichloroethene (1,1-DCE);

1,1 dichloroethane (1,1-DCA); and 1,1,1 trichloroethane (1,1,1-TCA) at levels above

federal and state primary drinking water standards. Four non-site related metals: barium,

beryllium, chromium and antimony were also discovered at concentrations in excess of

drinking water standards.

IV. Remedial Actions

A. Remedy Selection

The remedial action objectives identified in the Record of Decision (ROD) issued

September 30, 1992, are:

"S" Prevent ingestion of water which contains compounds in concentrations that

exceed federal and state enforceable drinking water standards; and

"S" Prevent ingestion of water containing compounds which have no enforceable

federal or state drinking water standards but which pose an unacceptable health

risk.

The ROD identified natural attenuation with monitoring for remediation of site ground

water and institutional controls to prevent consumption of contaminated ground water

until ground water cleanup levels were attained. With regard to metals, the ROD

concluded that elevated concentrations were probably due to sampling artifacts and not

representative of actual conditions. Re-sampling of groundwater by an improved method

(low-flow) was required to verify actual conditions.

B. Remedy Implementation

Groundwater monitoring was performed by the New Hampshire Department of

Environmental Services (NH DES) until a Unilateral Administrative Order was issued to

the Town of Londonderry on September 30, 1996. The Town was the only potentiallyresponsible party identified for the Site. The Town implemented required institutional

controls and hired a consultant to perform continued groundwater monitoring.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page 4

C. System Operations/Operation and Maintenance (O&M)

Currently, the remedy remains monitored natural attenuation and the ground water is

sampled once a year in the late fall. Ground water monitoring data indicates that the

cleanup of the ground water is progressing as anticipated. The ROD cleanup goals for

ground water, developed in response to the remedial action objectives, along with the

maximum levels of contaminants found in monitoring wells since the last five-year

review are presented in Table 2, below. See Figure 1 for the location of the monitoring

wells.

Barium, beryllium, chromium and antimony were re-sampled using the low-flow

sampling method. Results confirmed that actual concentrations did not exceed drinking

water standards. Three rounds of subsequent monitoring were performed which verified

this result. Metals were removed from the monitoring program.

Table 2: ROD Ground Water Cleanup Goals and Results

Contaminant

1,1,1 -Trichloroethane

1,1-Dichloroethene

1,1-Dichloroethane

Target

Level (jig/1)

200

7

81

1999-2002 Maximum/

Well No.

85 ng/l/MW-2D-6

48 ug/l/MW-2D-6

120 ug/l/MW-2D-6

2003 Maximum/

Well No.

19 ug/l/MW-2D-6

28 ug/l/MW-2D-6

57 ng/l/MW-2D-6

Maintenance primarily involves ensuring the integrity of the monitoring network so that

representative samples can be obtained. A written agreement between Stonemark

Investments, Inc., the developer of Saddleback Road and the Town of Londonderry, dated

December 11, 1996, includes provisions for long-term access to, and maintenance of,

monitoring wells. Durong the constructionof the Saddleback Road subdivision, MW-2S

was destroyed and MW-2D damaged, but Stonemark Investments, Inc. implemented the

necessary repairs consistent with the above agreement.

V. Progress Since the Last Five-Year Review

The last five-year review contained four recommendations for ensuring the protectiveness

of the remedy. The status of their implementation is presented below:

(1) The current annual groundwater monitoring program should continue

The annual ground water program has continued and is documented in annual

reports provided to EPA and NHDES.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page S

(2) Monitoring wells MW-2S and MW-2D are critical monitoring locations

and should be replaced and/or repaired, as necessary, to effectively

monitor continued progress towards achievement of remedial objectives

Both wells were addressed so that no data was missed. Repairs were made to MW-2D

and MW-2S was replaced on November 18, 1999, prior to the annual sampling event.

(3) The Groundwater Management Permit should be maintained to ensure

that potable wells are not installed within the plume area

The permit duration is five years and was renewed in August 2002. No evidence was

found of any new drinking water wells having been installed.

(4) Surface water in the wetland area directly downgradient of the plume

should be sampled once drinking water standards are achieved to ensure

compliance with CWA <f> 304(a)

This recommendation is still valid, since drinking water standards have not been met in

all wells.

VI. Five-Year Review Process

A. Administrative Components

The Town Garage/Radio Beacon Superfund Site five-year review was conducted by

Roger Duwart, with assistance from James DiLorenzo, the EPA Remedial Project

Manager, and Andrew Hoffman, the NHDES Remedial Project Manager.

B. Community Involvement

Copies of the review are being placed in the information repositories, including the Leach

Public Library in Londonderry, New Hampshire. A copy is being provided to the Town

Manager.

C. Document Review

This five-year review consisted of a review of relevant documents including Applicable

and Relevant or Appropriate Requirements (ARARs), the Groundwater Management

Permit, and monitoring data provided by the town of Londonderry's consultant. The

sampling documents reviewed are presented in Attachment A.

D. Data Review

Review of records and monitoring reports through November of 2003, indicates that the

remedy is performing as expected.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page 6

For the site, six ground water Chemicals of Concern were identified and had cleanup

levels set. In the latest ground water sampling round (November, 2003), ten compliance

wells and three residential wells were sampled. Only one Chemical of Concern, 1,1-

dichloroethene, was found in only one well, MW-2D1, above its cleanup level. Historical

trends for several monitoring wells are presented in Attachment B.

E. Site Inspection

Representatives of EPA and NHDES, participated in the site inspection held on

February 27, 2004. During the inspection, the residential development, town garage area

and the ground water monitoring wells were observed. No potable wells were observed.

F. Interviews

The attorney representing the Town was contacted for an interview. No concerns were

raised.

VII. Technical Assessment

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

The ROD estimated that the ground water would achieve cleanup levels through natural

attenuation within seven to twenty-five years. Eleven years have passed and all but one

Chemical of Concern in all but one fracture zone from one bedrock well has achieved

cleanup levels. Moreover, a downward trend is evident in that fracture zone

(see Figure 4). Therefore, it would appear that the remedy is functioning as intended.

B. Are the exposure assumptions, toxicity data, cleanup levels, and remedial action

objectives used at the time of remedy selection still valid?

There have been significant changes in land use on the site. However, the residential

development which has occurred on the site is served by public water and no additional

drinking water wells have been installed.

Under the 1986 cancer guidelines (U.S. EPA, 1986), 1,1-DCE (a Chemical of Concern

for the site) was assigned to Group C, a possible human carcinogen. However, under the

draft revised guidelines for carcinogenic risk assessment (U.S. EPA, 1999), EPA has

concluded that the data for 1,1-DCE are inadequate for an assessment of human

'This is a bedrock well with permanently installed packer devices which extract samples

from discrete fracture zones. Six such zones exist in this well. Only the deepest fracture zone,

MW-2D-6 has 1,1-dichloroethene present above its cleanup level.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page 7

carcinogenic potential by the oral route. Therefore, a quantitative estimate of

carcinogenic risk from oral exposure cannot be calculated. The federal and state drinking

water standards remain at 7 ng/1, however.

No other changes have occurred in toxicity assumptions for site-related Chemicals of

Concern.

The following applicable or relevant and appropriate requirements (ARARs) were

reviewed for changes that could affect protectiveness:

Safe Drinking Water Act (40 CFR Part 141)

Resource Conservation and Recovery Act (40 CFR 264)

Clean Water Act (40 CFR 122)

New Hampshire Code of Administrative Rules Env-Wm 1403 (formerly Env-Ws

410)

No ARARs or "To Be Considered" criteria were changed which would affect the

protectiveness of the remedy. Thus, the remedy is protective and in compliance with

these ARARs.

C. Has any other information come to light that could call into question the

protectiveness of the remedy?

No other information has come to light which would call into question the protectiveness

of the remedy.

Technical Assessment Summary

The following conclusions support the determination that the remedy for the Town

Garage/Radio Beacon Superfund Site remains protective of human health and the

environment.

** Residential development has occurred on the site. However, public

water is provided and therefore the remedy remains protective.

** A Groundwater Management Permit remains in effect to ensure that no new

drinking water wells are installed within the site boundaries.

** No new contaminants, sources or exposure pathways were identified

during this five-year review.

** The ground water flow patterns are consistent with the expectations at

the time of the decision documents.
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 PageS

<** A ground water monitoring plan is in place, sufficient to identify

potential future problems and to provide information to address them, if

necessary.

<** The remedy is performing as expected and there are no indications of a

potential failure.

VIII. Issues

No issues were identified during this review.

IX. Recommendations and Follow-up Actions

The consultant for the town of Londonderry will continue to sample residential and

monitoring wells. If the results of sampling indicate that additional remedial actions are

needed, options will be e\ aluated and implemented which would protect the public

health.

The consultant for the town of Londonderry will sample surface waters after all

monitoring wells have achieved cleanup levels.

The Groundwater Management Permit will remain in-place until all monitoring wells

have achieved cleanup levels.

Recommendations/

Follow-up Actions

Monitor ground water annually

Monitor surface water

Maintain institutional controls

through Groundwater

Management Permit

Party

Responsible

Londonderry

Londonderry

Londonderry

Oversight

Agency

EPA/NHDES

EPA/NHDES

EPA/NHDES

Milestone Date

Late fall each year

When all ground

water cleanup levels

have been achieved

Until all ground

water cleanup levels

have been achieved

Follow-up Actions:

Affects

Protectiveness

(Y/N)

Current

N

N

N

Future

N

N

N
Town Garage/Radio Beacon Superfund Site

Second Five-Year Review, March 2004 Page 9

X. Protectiveness Statement

Because the remedial actions being implemented throughout the Town Garage/Radio

Beacon Superfund Site are protective, the site is protective of human health and the

environment.

XI. Next Review

This site requires policy reviews every five years since upon completion of the remedial

action no hazardous substances will remain above levels that allow for unlimited use and

unrestricted exposure, but five or more years are required to reach that point. The next

review will be issued either on or prior to five years from the date of signature of this

report.
ATTACHMENT A

DOCUMENTS REVIEWED

"Groundwater Management Permit," New Hampshire Department of Environmental Services,

August, 1997.

"Annual Report, 1999 Groundwater Monitoring Program, Town Garage/Radio Beacon Site,

Londonderry, New Hampshire," Sanbom, Head & Associates, Inc., January 2000.

"Annual Report, 2000 Groundwater Monitoring Program, Town Garage/Radio Beacon Site,

Londonderry, New Hampshire," Sanborn, Head & Associates, Inc., January 2001.

"Annual Report, 2001 Groundwater Monitoring Program, Town Garage/Radio Beacon Site,

Londonderry, New Hampshire," Sanborn, Head & Associates, Inc., January 2002.

"Annual Report, 2002 Groundwater Monitoring Program, Town Garage/Radio Beacon Site,

Londonderry, New Hampshire," Sanborn, Head & Associates, Inc., January 2003.

"Annual Report, 2003 Groundwater Monitoring Program, Town Garage/Radio Beacon Site,

Londonderry, New Hampshire," Sanborn, Head & Associates, Inc., January 2004.
ATTACHMENT B

FIGURES
LAYOUT: FIGURE

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