7-0 LA") CINYR-APT Co G (RP1.o L:-Vrecm

SUPERFUND SITE PRELIMINARY CLOSE OUT REPORT

Holton Circle Groundwater

Contamination Superfund Site

Londonderry, New Hampshire

September 30, 1992
I. INTRODUCTION

This Preliminary Close Out Report documents that the

Environmental Protection Agency (EPA) has issued a Limited Action

Record of Decision for the Holton Circle Groundwater

Contamination Superfund Site in Londonderry, New Hampshire.

Limited Action RODs require no construction activities, therefore

a pre-final inspection is not necessary. Activities required to

attain site completion are underway.

II. SUMMARY OF SITE CONDITIONS

Background

The Holton Circle Groundwater Contamination Superfund Site

includes a residential development of 23 homes (Holton Circle),

the Londonderry Town Garage area located approximately 1/4 mile

west of Holton Circle on High Range Road, and an undeveloped hill

slope and wetland area between the Town Garage and Holton Circle

which, in total, comprise approximately 100 acres of land in

Londonderry, New Hampshire (see enclosed Site Location Map).

The property where the Town Garage is located was previously

owned by the United States Department of Defense and used as a

radio beacon facility. Because of their current ownership of the

property, the Town of Londonderry has been named as the only PRP,

to date, at the Site. Excluding the Town Garage, land use in the

immediate Site area is strictly residential. Drinking water in

the area is obtained via private bedrock wells except for nine

residents on Holton Circle and the residents of the adjacent

Isabella Drive development, all of whom use public water from the

Southern New Hampshire Water Company which was installed during

1989 and 1990.

The only health threat which exists at the site is from the

future ingestion of contaminated groundwater. The primary

contaminants of concern at the site are 1,1 dichloroethene (DCE),

1,1,1 trichloroethane (TCA) and several inorganics including

chromium (total), barium, beryllium, and antimony.

The Site was proposed to the National Priorities List (NPL) on

June 21, 1988, and was added to the final list on March 31, 1989.

Selected Remedy

On September 30, 1992, the Regional Administrator signed a Record

of Decision (ROD) for the Site which specified the following

remedy:

1. restoration of contaminated groundwater in the

overburden and bedrock aquifers by natural attenuation;
2

2. institutional controls to prevent ingestion of

contaminated groundwater;

3. groundwater monitoring.

The goal of the selected remedy is to restore contaminated

groundwater to its beneficial uses in 2 to 3 years in the

overburden aquifer and 7 to 25 years in the bedrock aquifer. The

selected remedy includes no construction activities.

Interim Groundwater Cleanup levels, as summarized in Table 1

below, were established for 1,1 DCE, 1,1,1 TCA, chromium, barium,

beryllium and antimony.

TABLE I: INTERIM GROUNDWATER CLEANUP LEVELS

Carcinogenic Contaminants

of Concern

Interim

Cleanup

Level (ug/l)

Basis

Beryllium 4 MCLG

1,1 Dichloroethene 7 MCLG

Non-Carcinogenic

Contaminants

of Concern

Interim

Cleanup

Level(ug/1)

Basis

Antimony 6 MCLG

Barium 2000 MCLG

Beryllium 4 MCLG

Chromium 100 MCLG

1,1 Dichloroethene 7 MCLG

1,1,1 Trichloroethane 200 MCLG

• micrograms per liter (ug/l) = parts per billion (ppb)

At the time that these Interim Groundwater Cleanup Levels have

been achieved and have not been exceeded for a period of three

consecutive years, a risk assessment will be performed to

determine whether the remedial action is protective. The risk

assessment will follow EPA procedures and will assess the

cumulative carcinogenic and non-carcinogenic risks posed by

ingestion of groundwater.
3

If, after review of the risk assessment, the remedial action is

determined by EPA to not be protective for unrestricted uses, the

remedial action shall continue until either protective levels are

achieved and not exceeded for a period of three consecutive

years, or until the remedy is otherwise deemed protective. These

protective residual levels shall constitute the final cleanup

levels for the site.

OSWER guidance 9355.7-02 states that five-year reviews will be

conducted at sites where cleanup levels will take five or more

years to achieve (policy review). Therefore, five-year reviews

will be required during this natural attenuation activity.

III. DEMONSTRATION OF QA/QC FROM CLEANUP ACTIVITIES

EPA and State Quality Assurance/Quality Control (QA/QC)

procedures will be followed during implementation of the

monitoring program. Only EPA analytical methods will be used for

all validation and monitoring samples.

The QA/QC program to be utilized throughout the monitoring

program will be sufficiently rigorous and adequately complied

with to enable EPA and the State to determine that all analytical

results reported are accurate to the degree needed to assure

satisfactory execution of the monitoring program consistent with

the ROD.

IV. ACTIVITIES AND SCHEDULE FOR SITE COMPLETION

The following activities will be completed according to the

schedule in Table II below:

TABLE II: SCHEDULE FOR SITE COMPLETION.

Task Estimated

Completion

Responsible

Organization

1. Implementation of

institutional controls

June 1993 EPA and/or PRP

2. Final inspection September 2022 EPA/STATE/PRP

3. RA Report/Approval September 2022 EPA/STATE/PRP

4. Final Close Out Report December 2022 EPA

All preliminary completion requirements for the Site have been

met as specified in OSWER Directive 9320.2-3C. Specifically,

there are no construction activities at the Site and therefore,

no pre-final inspection is necessary.
4

A bibliography of all reports relevant to the preliminary

completion of this Site under the Superfund program is attached.

These documents are available for review by calling the Region 1

office at (617) 573-5729.

Approved By:

Merrill S. Hohman

Division Director

Waste Management Division
• 453

/ • • •

•

•

3

• ••• • .

• ,

HOLTON CIRCLE

394

'LondoncLer y

\\*

..\..

11\

Londonderry

• •

Moose

Hill'

ejiwood

m K 45s

LONDONDERRY

TOWN

GARAGE

34 

ou

•

N- D

200

r-7,• •n

CD

; A-117,e6,15

o -"r•

0

SCALE IN FEET

Source: USGS Topographic Maps:

Nashua North, NH 1968, Photorevised 1985

Manchester South, NH 1968, Photorevised 1985

Deny, NH 1968, Photorevised 1985

Windham, NH 1953, Photorevised 1985 (-\

2000 2000

FIGURE 1-1. LOCATION MAP, HOLTON CIRCLE, LONDONDERRY, NEW HAMPSHIRE

1 -1

••1iC•L n FOO•
REFERENCES

Metcalf & Eddy, "Remedial Investigation - Holton Circle

Groundwater Contamination Site", March 1992.

Metcalf & Eddy, "Feasibility Study - Holton Circle

Groundwater Contamination Site", June 1992.

United States Environmental Protection Agency, "Record of

Decision for the Holton Circle Groundwater Contamination

Site", September 1992.

United States Environmental Protection Agency, "Procedures

for Completion and Deletion of National Priorities List

Sites - OSWER Directive 9320.2-3A", April 1989.

United States Environmental Protection Agency, "Update to

the Procedures for Completion and Deletion of National

Priorities List Sites - OSWER Directive 9320.2-3B", December

29, 1990.

United States Environmental Protection Agency, "Update No. 2

to the Procedures for Completion and Deletion of National

Priorities List Sites - OSWER Directive 9320.2-3C", February

19, 1992.
SUBJECT: Holton Circle Close-Out Report

FROM: Jo Ann Griffith

Design and Constr tion Managem& Branch

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

SEP 25 092

OFFICE OF

SOLID WASTE AND EMERGENCY RESPONSE

MEMORANDUM

TO: Jim DiLorenzo

RPM, Region 1

Thank you for allowing me the opportunity to review the

Holton Circle Preliminary Close-Out Report. Based on my review,

I have the following comments:

Cover: The NCP specifies groundwater restoration as long-term

remedial actions. OGC (larry Starfield) has informed

me that this applies only to active measures such as

pump and treat and not natural attenuation. It has to

do with the state cost share provisions.

Page 2: In Table 1, you provide the interim clean-up goals and

the associated cancer and non-cancer risks. You may

want to provide the EPA acceptable risk levels for

comparison.

Page 3: Just an editorial comment here. The first sentence on

the page is a little long and convoluted.

In that same and the next sentence, the you say that at

the point the interim goals are met, a risk assessment

will be performed to "determine whether the remedial

action is protective." The site is already protective

with the use of institutional controls. What you mean

to say, is that if the clean-up goals are no longer

protective for unrestricted use, then the remedial

action will continue.

Five-year reviews will be required during this natural

attenuation activity. In the OSWER guidance 9355.7-02,

where the clean-up levels will take five or more years

to achieve (policy review).

46 Printed on Recycled Paper
-2-

You may want to make a statement to that effect in the

text. It will also need to be listed in the schedule

of activities, with completion dates.

We need a copy of the signed report as soon as possible. It

must be faxed or pouched (new mail code is 5203G). Please call

me if necessary to discuss my comments. My phone number is (703)

603-8774.