et seq., et seq., - arkansas times · previously operated by timex corporation (hereinafter...

ARKANSAS DEPARTMENT OF ENVIRONMENTAL QUALITY

IN THE MATTER OF:

TIMEX CORPORA TJON 2215 CRISP DRIVE LITTLE ROCK, ARKANSAS 72203 EPA ID No. ARD006349724 AFIN 60-00120 LIS 04-206-01

AMENDMENT TO CONSENT ADMINISTRATIVE ORDER LIS 04-206

This First Amendment to Consent Administrative Order (hereinafter "CAO") LIS 04-206 is

issued pursuant to the authority of the Arkansas Hazardous Waste Management Act, Ark. Code

Ann. § 8-7-201 et seq., the Arkansas Remedial Action Trust Fund Act, Ark. Code Ann. § 8-7-

501 et seq., the Arkansas Pollution Control and Ecology Commission (hereinafter "APC&EC")

Regulation 23, and APC&EC Regulation 8. The issues herein, as they pertain to the property

previously operated by Timex Corporation (hereinafter "Timex") at 2215 Crisp Drive, Little

Rock, Pulaski County, Arkansas, having been settled by the agreement of Timex and the

Arkansas Department of Environmental Quality - Hazardous Waste Division (hereinafter

"ADEQ"), it is hereby agreed and stipulated by all parties that the First Amendment be entered

herein.

1. CAO LIS 04-206 stated, "Timex and ADEQ shall, if necessary, amend this CAO to

implement the remedy proposed by Timex and approved by ADEQ." Paragraph 4, Order

and Agreement, CAO LIS 04-206.

2. The purpose of the First Amendment is to implement the remedial action(s) as described

in the remedial action decision document (RADD) incorporated as Attachment A and to

establish the goals and guidelines for the remedial action.

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4. With the exception of paragraphs 4 and 9 of the Order and Agreement of CAO LIS 04-

206, the language of that CAO is incorporated verbatim into the First Amendment.

5. All provisions ofCAO LIS 04-206 not expressly modified herein remain in full force and

effect.

WORK TO BE PERFORMED

6. While Timex does not admit to any matter, factual or legal, by entering into this CAO,

Timex agrees to undertake the following actions:

A. Institutional controls:

i. Timex will obtain an ordinance from the City of Little Rock, or deed

restrictions, or both limiting use of the impacted property(ies) south of 12th Street to

industrial use ("Industrial Use Institutional Controls"). For purposes of the Industrial

Use Institutional Controls, the impacted property(ies) south of 12th Street are those that

lie within the area of the shallow groundwater TCE plume emanating from 2215 Crisp

Drive. The use restrictions will include the same uses as the current zoning, which is I-2

(light industrial district) as defined in Section 36-320 of the Little Rock Code of

Ordinances (attached), with the following exceptions: day nursery or day care center

(see 36-320(c)(1)(w)); adult day care center (see 36-320(c)(l){x)); any eating

establishment (see 36-320(c)(l )(y)-{z)); business school (see 36-320(c)(l )(ddd));

commercial, trade or craft school (see 36-320(c){l){eee)); bus station and terminal (see

36-320(c)(2)(b)); hotel or motel (see 36-320(c)(2)(d)); or drive-in theater (see 36-

320(c)(2)(j)) that also includes child care or play facilities . All necessary deed notices

will be filed for the affected properties within one hundred twenty ( 120) days from the

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effective date of the First Amendment. File-marked copies of the notices will be

submitted to ADEQ within thirty (30) days ofthe filing.

11. Timex will obtain an ordinance from the City of Little Rock, or deed

restrictions, or both on individual parcels restricting development of groundwater to

prevent potential human exposure to contaminants in groundwater ("Groundwater Use

Institutional Controls"). For purposes of the Groundwater Use Institutional Controls,

the individual parcels to be covered are those that lie within the area of the deep and

shallow groundwater TCE plumes emanating from 2215 Crisp Drive. Timex will

provide quarterly status updates to ADEQ regarding Timex's efforts to obtain the

required institutional controls. If such institutional controls cannot be put into place as

described, written notification must be submitted to ADEQ stating the needed institutional

controls are not achievable and that remedial alternatives will be reevaluated. The revised

remedial alternative must be submitted for review and approval by ADEQ forty-five (45)

days following notification that the necessary institutional controls are not achievable.

B. Remediation:

1. Timex will submit a detailed schedule of remedial activities to include

submittal of a Treatment Technology Pilot Test Work Plan, Remedial Action Work Plan

and a Groundwater Monitoring Plan, each to include a schedule for implementation.

This schedule will be submitted to ADEQ for review and approval within sixty (60) days

of the effective date of the First Amendment.

ii . An access agreement will be put into place to allow Timex to implement

the remedy. A signed copy of this agreement will be submitted to ADEQ within thirty

(30) days of the effective date of the First Amendment.

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iii. The Remedial Action Work Plan shall provide for active soil remediation

consisting of excavation and off-site disposal of unsaturated soils exceeding 0. 78 mglkg

of TCE. The excavation will be backfilled with imported clean fill. If the institutional

controls set forth in Paragraph 6.A.i are unattainable, Timex must develop and propose an

additional remedial strategy, subject to ADEQ approval.

IV. The Remedial Action Work Plan shall provide for in situ chemical

oxidation ("ISCO") via injection of an appropriate oxidant into the shallow groundwater.

Active treatment using ISCO will be performed on the shallow aquifer to treat

groundwater contamination exceeding 1.96 mg/L TCE. Following active treatment,

Timex will transition to monitored natural attenuation pursuant to Paragraph 6.C. for both

the shallow and deep groundwater. If the institutional controls set forth in Paragraph

6.A.ii are unattainable, Timex must reevaluate the remedial approach for groundwater

and propose alternate remediation approaches for the off-site groundwater contaminant

plume beneath properties without groundwater use restrictions to achieve the remedial

action levels beneath such properties. Consistent with Paragraph 6.A.ii, the revised

remedial action alternative must be submitted to ADEQ for review and approval.

v. For deep groundwater, the Remedial Action Work Plan shall provide

solely for monitored natural attenuation following the completion of active treatment in

the shallow groundwater. The Groundwater Monitoring Plan, to be approved by ADEQ,

will provide details for well selection, parameters, and sampling frequency for monitored

natural attenuation.

vi . Nothing herein shall prevent Timex from proposing any changes to the

work to be performed under Paragraph 6 at any time. Any such proposed changes are

subject to ADEQ review and approval, such approval not to be unreasonably withheld.

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vu. The goal of the remedial action is to attain the Remedial Action Levels in

Tables 1 and 2 following active treatment and monitored natural attenuation.

Table 1: Remedial Action Levels for On-Site Soils

Chemical Surface Soil Subsurface Soil Subsurface Soil Remedial Remedial Action Remedial Action

Action Level Level (mglkg) Level if Applicable (mglkg) Institutional Controls

Are Not Put Into Place (mg/kg)

I, 1 -dichloroethane ( 1, I-DCA) NA 0.0068 0.0068

1, 1 -dichloroethene ( 1, 1-DCE) NA 0.025 0.025

cis- I ,2-dich loroethene ( c-DCE) NA 0.21 0.21

1,1, 1-trichloroethane (1, 1, 1-TCA) NA 0.70 0.70

Trichloroethylene (TCE)1 6.4 0.78 O.Ql8

Table 2: Remedial Action Levels for Groundwater

Chemical Remedial Action Remedial Action Level ("giL) if Level ("giL) Applicable Institutional

Controls Are Not Put Into Place

1,1, 1-trichloroethane (1, 1,1-TCA) 200 200

1,1 ,2-trichloroethane ( 1,1 ,2-TCA) 5.0 5.0

1, 1-dichloroethane ( 1, 1-DCA) 2.4 2.4

1 ,2-dichloroethane (1 ,2-DCA) 5.0 5.0

1,1 -dichloroethene ( 1, 1-DCE) 7.0 7.0

cis-1 ,2-dichloroethene (c-DC E) 70 70

1 ,4-Dioxane 0.67 0.67

Freon 113 53,000 53,000

Tetrachloroethylene (PCE) 5.0 5.0

Trichloroethylene (TCE)2 1,960 (on-Site)/5 .0 5.0

1 The only active remediation to be conducted for soil is excavation as specified in Paragraph 6.B.iii relating to soil impacted with TCE above the specified thresholds in that paragraph.

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(off-Site)

Vinyl chloride 2.0 2.0

Manganese 50 50

C. Monitoring: Following active treatment, if groundwater monitoring results indicate the

remedial actions taken have been effective (i.e., concentrations within the plume are stable or

declining) after five (5) years of monitoring, the Groundwater Monitoring Plan shall provide for

changes in sampling locations, constituents, and frequency of monitoring activities. If, however,

remedial actions have not been effective after five (5) years of monitoring (i.e., concentrations

within the plume are increasing}, additional remedial actions will be required. A plan for the

additional evaluation and remedial activities will be submitted for review and approval forty-five

( 45) days following notification from ADEQ that the current remedy is not effective.

LANDOWNER NOTIFICATIONS

7. Timex will send a letter of Notification of Contamination to potentially impacted

landowners by registered mail within thirty (30) days of the effective date of this First

Amendment. Timex also will provide direct notice to impacted landowners and tenants

describing the extent, chemical properties, and potential risks of exposure to persons known to

work or reside within defined areas known to be contaminated and describing source control

measures or remedies to be implemented.

8. Timex will submit a community relations plan to ADEQ within sixty (60) days of the

effective date of this First Amendment that includes a mechanism to keep impacted landowners

and tenants informed throughout the duration of the remediation and a schedule to submit copies

2 The only active treatment to be conducted for groundwater is the treatment of shallow groundwater with ISCO as specified in Paragraph 6.B.iv. This active treatment will be followed by monitored natural attenuation for all specified contaminants in both the shallow and deep groundwater as described in Paragraph 6.C.

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of letters and mail receipts to ADEQ within the remedial timeframe to demonstrate completion

of the tasks in Paragraph 7.

GENERAL PROVISIONS

9. Timex hereby designates a Project Manager who shall be responsible for overseeing the

implementation of all site investigation, remediation and closure activities subject to the

requirements of CAO LIS 04-206 and the First Amendment. The Project Manager shall

communicate with ADEQ on all technical issues which arise under CAO LIS 04-206 and the

First Amendment and shall be empowered to agree on minor modifications in the

implementation of any of the investigation or remediation tasks subject to the requirements of

CAO LIS 04-206 and the First Amendment when such modifications are deemed by ADEQ to

further the purpose of CAO LIS 04-026 and the First Amendment. Timex may cha nge its

Project Manager at any time by providing written notice of such change to the ADEQ. The

initial Project Managers shall be:

For Timex:

Jane Spellman FTN Associates Ltd.

124 W. Sunbridge Drive, Suite 3 Fayetteville, AR 72703

(479) 571-3334

ForADEQ:

Hazardous Waste Division Chief Arkansas Department of Environmental Quality

5301 North Shore Drive North Little Rock, AR 72118

(501) 682-0831

10. Timex agrees to provide financial assurance for the total estimated cost of the corrective

action for a 30-year period utilizing the current cost estimates. This estimated cost will include

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the remedial actions presented in Paragraph 6. Within sixty (60) days of the effective date of the

First Amendment, a financial assurance mechanism will be in place which adheres to APC&EC

Regulation No. 23, § 265.143. The cost estimate and financial assurance mechanism will be

updated annually subject to approval of ADEQ.

11. CAO 04-206, as amended, shall terminate following the completion of all remedial

activities outlined in the RADD.

12. This Amendment shall be effective upon signature by both Timex and ADEQ. Unless

otherwise specified in this Amendment, all times for performance of ordered activities shall be

calculated from this effective date.

13. It is the intent of the parties that the CAO, by incorporating the RADD, sets forth the

entirety of Timex's obligations with regard to the remedial activities to be undertaken regarding

the Site.

(a) In consideration of the actions that will be performed by Timex under this CAO, ADEQ

covenants not to sue or to take administrative action against Timex pursuant to the Arkansas

Hazardous Waste Management Act, the Arkansas Remedial Action Trust Fund Act, or APC&CE

Regulations 8 and 23 for any remedial work or response costs related to the Site. These

covenants are conditioned upon the satisfactory performance by Timex of its obligations under

this CAO.

(b) Specific Reservation of Rights. ADEQ reserves, and this CAO is without prejudice to,

ADEQ's right to seek to compel Timex to undertake additional response actions if, prior to

completion of the remedial action contemplated by the CAO, conditions at the Site, previously

unknown to ADEQ are discovered, or information, previously unknown to ADEQ, is received in

whole or in part, and ADEQ determines that these previously unknown conditions or information

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together with any other relevant information indicates that the remedial action is no longer

protective of human health and the environment.

(c) General Reservations of Rights. ADEQ reserves and this CAO is without prejudice to,

all rights against Timex with respect to all matters not expressly included within ADEQ's

covenants. Notwithstanding any other provision of this CAO, ADEQ reserves all rights against

Timex with respect to:

a. liability for failure by Timex to meet a requirement of this CAO;

b. liability arising from the past, present, or future disposal, release, or threat of

release of hazardous material or hazardous waste not associated with the Site;

c. liability based on Timex's transportation, treatment, storage, or disposal, or

arrangement for transportation, treatment, storage, or disposal of hazardous materials or

hazardous waste at or in connection with the Site, other than as provided in the CAO or

otherwise ordered by ADEQ, after signature of this CAO by Timex;

d. liability for violations of federal or state law that occur during or after

implementation of the actions outlined in the CAO.

(d) Subject to the preceding subparagraphs of Paragraph 13, nothing in this CAO shall be

deemed to limit any authority of ADEQ (a) to take all appropriate action to protect human health

and the environment or to prevent, abate, respond to, or minimize an actual or threatened release

of hazardous materials or hazardous wastes on, at, or from the Site, or (b) to direct or order such

action, or seek an order from a court of Jaw, to protect human health and the environment or to

prevent, abate, respond to, or minimize an actual or threatened release of hazardous materials or

hazardous wastes on, at, or from the Site.

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14. By virtue of the signature appearing below, the individual represents that he or she is an

Officer of Timex, being duly authorized to execute and bind Timex to the terms contained herein

as attested by the secretary of said entity. Execution of the First Amendment to CAO LIS 04-206

by an individual other than an Officer of Timex shall be accompanied by a resolution granting

signature authority to said individual as duly ratified by the governing body of the entity.

:?1-t:;_ ~~I SO ORDERED THIS__._~~-.£---- DAY OF f?.,hYUli,Ct-f , 2014.

TERESA MARKS DIRECTOR

APPROVED AS TO FORM AND CONTENT:

BY: Signatur

Title VP- Ass i s tant General Couns el

Date February 21, 2014

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RESPONSE TO COMMENTS &

FINAL DECISION

on the

REMEDIAL ACTION DECISION DOCUMENT (RADD)

A. INTRODUCTION

Former Timex Facility 2215 Crisp Drive

Little Rock Pulaski County

Arkansas

AFIN: 60-00120

On January 20, 2014, the Arkansas Department of Environmental Quality - Hazardous Waste Division (ADEQ) proposed a Remedial Action Decision Document (RADD) for the former Timex Facility, 2215 Crisp Drive in Little Rock, Pulaski County, Arkansas. This RADD outlines the proposed remedy for the property.

This Response to Comments and Final Decision addresses and documents for the public record the comments and issues raised concerning the notice of the RADD, provides the Department's response to the issues raised during the public participation process; and sets forth the final decision and approval of the RADD attached herein.

B. SELECTED REMEDY

The selected remedy for the former Timex Facility is set forth in the attached final Remedial Action Decision Document (RADD).

Within thirty (30) days of completing all activities outlined in the RADD, the Timex Group U.S.A. , Inc. shall submit to ADEQ for review and approval a completion report. The completion report shall include information to document that no unacceptable risks, as described in A.C.A. § 8-7-502), remain on-site as a result of the release of hazardous substances, and the site has been remediated in accordance with the provisions set forth in the RADD. The completion report shall be reviewed by ADEQ and, upon written approval by ADEQ, a letter ofNo Further Action will be issued.

C. PUBLIC PARTICIPATION ACTIVITIES

The ADEQ issued a public notice of the RADD on January 20, 2014. Notice was published in the Arkansas Democrat Gazette on January 20, 2014. The public comment period closed on February 20, 2014. No comments were received during the comment period.

D. PUBLIC COMMENTS AND THE DEPARTMENT'S RESPONSE

No comments were received during the public comment period.

E. FUTURE ACTIONS

Effective with this Decision, the final Remedial Action Decision Document is incorporated into and becomes a condition of the Amended Consent Administrative Order between Timex Group U.S.A., Inc. and the Department, as though set forth therein line for line and word for word.

F. DECLARATIONS

ADEQ believes that the remedy set forth in the RADD for the former Timex Facility in Little Rock, Arkansas is appropriate, technically feasible, reliable, and cost effective. With respect to risk management decisions made by ADEQ, this remedy is deemed acceptable, and to be protective of human health and the environment.

G~ Chief

2 7 k6. 2oJ4-(Date)

Hazardous Waste Division Arkansas Department of Environmental Quality

Enclosure: Final RADD

2

STATE OF ARKANSAS

ARKANSAS DEPARTMENT OF ENVIRONMENTAL QUALITY

REMEDIAL ACTION DECISION DOCUMENT

Former Timex Property

AFIN 60-00120

Little Rock, Pulaski County, Arkansas

February 2014

Table of Contents

1.0 Introduction ........... ......... ..... ... .......................................................... ... ....................................... ....... ]

2.0 Site Background .................. ..... ....... ... ... ......................................................... .......... ... ..... ... .......... .. .. 1

2.1 Hydrogeological Setting .......... .... ... .... ...... .. ... ...... .. ...... .. .............. .. ... ... ....... .. ...... ..... ... ........... .... .. .... .... 2

2.1.1 Site Geology .. .. ... ... ... ..... ... .... ............ ... ....... .. ....... ......... ....................................................... .... ..... 2

2.1.2 Site Hydrogeo logy ........ ..... .................................. .... ........ .. ... .. .......................... ..... ....... ... ....... ... ... 2

2.2 Previous Investigations .... .... ..... ............... ........... ....... ......... ..... ...... .... ............. .. .................................. 3

3.0 Summary of Site Risks ............ ..... ... ............. ........... ....... .............. .... ......... .... .... .... ..... .... ... .... .... .... .......... 4

3.1 Chemicals of Potential Concern in Surface Soil ........... ....... .... ........... ....... .... ..... ........ ..... ..... ... ........ .. .4 3.2 Chemicals of Potential Concern in Subsurface Soil. ........... .......... ............. .. ..... ............... .. ........ ........ .4 3.3 Chemicals of Potential Concern in Groundwater ....... ..... .... ..... ... ...................... ....... ... .. ...................... 5

3.4 Chemicals of Potential Concern in Indoor Air .... .... ............ ...... .... .. .... ... ......................... ..... .... ..... ...... 5

3.5 Chemicals ofPotential Concern in Surface Water ................................... ......... ............... .. .......... ....... 6

3.6 Chemicals of Potential Concern in Sediment Data ............................................................................. 6

3. 7 llliRA Summary ....................................................................................................... ...... ............. ....... 6

3.8 Screening Level Eco logical Risk Assessment (SLERA) Summary ........... ... ...................... .. .............. 7

4.0 Sum1nary of Remedial Approach ......... ............................ .......... ..... ....... ... .. ...... .. .......................... .... ...... 7

5.0 Summary of Alternatives Considered ..................................................................................................... 8

5.1 Soils ......... ... ... ....... ... .... ... ..... .... .... .... ....... ..... ... ............ .... ... ..... ..... ................ .. .. ... .... ...... ...... ... .............. 8

5.2 Groundwater ........................................................................................................................................ &

5.2.1 In Situ Technologies ..... ... ........ ...... .. .................... ... .... ..... ..... ................ .. ..... .... ..... ..... ............ ..... .. &

5.2.1.1 In Situ Biodegradation ..... ... .. ... .. .. .. ... ............. .. ..... .. ........ .. ..... .. ...... ...... ... .. ............. ..... ........... &

5.2.1.2 In Situ Chemical Oxidation (ISCO) ...................................................................................... 9

5.2.2 Ex Situ Treatment Technologies .......... ................... ...... ..... ... .. ................... ...... .... ... ..................... 9

5.2.2.1 Groundwater Extraction ...... ........ ..... ....... ............... .... .... ........... ............................................ 9

5.2.2.2 Air Stripping .......................................... ........ ... .... ....... .... ....... ... ... .... ... .... ... .. .. .. ... ... ... .. ...... ... . 9

5.2.2.3 Activated Carbon ............................................................................................................ ... .. 1 0

5.2.2.4 Ultraviolet (UV) Oxidation ......................................................................................... ...... .. 1 0

5.3 Disposal Technologies ................. ... ............. .. ............ .... ...... ... .. .......... ................................. ....... ...... 10

5.3.1 Discharge to Publicly Owned Treatment Works (POTW) ........................................ ...... ........... 10

5.3.2 Discharge to Surface Water. ....................................................................................................... 10

5.4 Monitored Natural Attenuation (MNA) .... ...... .................... .... .... .... .. ........ .. .............. ........................ 11

5.5 Institutional Controls ................................................................................................... ......... ... .. ........ 11

5.6 No Action .......................................................... .................... ..... ...... .. ........... .... ... ............... .............. 11

5. 7 Additional Alternatives Considered .................. .. ................ .................... ...... ........................... .. .. .. .. . 11

5.8 Summary of Screened Technologies ........................................ .. ........................................ ...... ......... 12

6.0 Proposed/Recommended Remedies ................................................................................................ 14

7.0 Evaluation of the Proposed Remedy and Alternatives .................................................................... 14

8.0 Remedial Action Levels .. ...... ........ .......................................................... ....... .. ..... .. .. ...................... 14

8.1 Soil Remedial Action Levels .... .. ... .. .............. .. ........ .. ...... .. ...... ......... .. .......... ..... ..... .... ... ...... .. .. .... 16

8.2 Groundwater Remedial Actions Levels ...................................................................................... 16

9.0 Justification for Selections .............................................................................................................. 18

9.1 Soils .............. .... .. ...... ....... .. .. ...... ....... .. .. ...... .. .... ......... .............. ..... ... ... ..... ... : ............. ...... .. .... ...... .. ... .. IS

9.2 Groundwater .............. ........ ... ..... ..... ....... ............. ...... .... ........ ... ........ .............................. ............ ... ... .. IS

10.0 Selected Remedy/S ite Plan .............................................................................................................. 18

11.0 Financial Assurance ....... ........ ..... ..... .. .............. ...... ....... ....... .......... ... .... ... ............ ....... .................... 19

12.0 Effectiveness Monitoring Program ................................................................................................. 19

13.0 Community Participation ................. .............. ... ........ .. .......................................... ..... .... .............. ... 20

14.0 Coordination with Other Divisions/Agencies ................................................................................. 20

Appendix A: Figures

Figure 1: Site Location

Figure 2: Site Layout

Figure 3: Distribution ofTCE in Shallow Sand Aquifer

Figure 4: Distribution ofTCE in Deep Sand Aquifer

Figure 5: Extent of Soils Exceeding RAL for TCE

1.0 Introduction This Remedial Action Decision Document (RADD) is written for the former Timex Facility (Site). The Site is located at 2215 Crisp Drive in Little Rock, Pulaski County, Arkansas (Figure 1). The 9-acre parcel is zoned as light industrial (I-2) and is currently a fenced vacant lot partially covered by aged asphalt and grassy vegetation. This description of the Site is used in the Human Health Risk Assessment; however, because Timex leased the property and the Little Rock National Airport Authority (Airport) owns the property, for remedial purposes the former Timex Facility and all contiguous property owned by the Airport and zoned light industrial will be considered on-site. Crisp Drive borders the property on the north, and across Crisp Drive there is vacant land that is owned by the Airport, University of Arkansas at Little Rock, and the City of Little Rock. A residential neighborhood of small single-family homes is located about 700 feet (ft.) north of the Site. To the south and east the Site is bordered by property owned by the Airport that is leased to the Central Flying Service. An alley runs between the Site and the former Razorback Metals facility to the west. Bond A venue lies further to the west, and the property across Bond A venue is occupied by Choctaw, Inc., which is a concrete products manufacturing facility (Figure 2).

This RADD describes alternatives for remedial action regarding hazardous substances contamination as result of past activities at the Site. This document also describes the remedial alternatives selection process used by the Arkansas Department of Environmental Quality (ADEQ) for this Site. The general public is afforded an opportunity to comment on the decisions made in this document.

2.0 Site Background The Site was part of an army depot between 1918 and 1931 and was used for storing and cleaning airplane parts and engines, assembling planes during World War I (WWI) and for storing surplus war supplies. The Little Rock National Airport became the Site owner after WWI. The former facility building, known as Building 19, actually consisted oftwo large buildings separated by a railroad spur used for loading and unloading airplane parts.

A cotton company leased the building from 1931 to 1939, and the building was used as a specialized depot by the War Department during WWII. The Air National Guard occupied the southwest corner ofthe building beginning in 1939 and continued to occupy it until the early 1970s.

Between 194 7 and 2000, Timex leased the facility and property for the manufacture of watches, clocks, and Polaroid cameras. Former manufacturing processes included cutting, stamping, grinding, sanding and plating metal and aluminum watch bezels and case backs, as well as injection molding of plastic watch cases.

Prior to the discontinuation of manufacturing operations at Timex, the Airport hired Pollution Management (PMI) to conduct a Phase I Environmental Site Assessment (ESA). Both the Airport and Timex retained PMI to conduct a Phase II ESA. The Phase II ESA indicated that past operations involving chlorinated solvents had affected groundwater quality beneath the

property, but that further investigation was necessary to define the source and extent of the impact. As a result, Timex entered into a Consent Administrative Order (CAO) for voluntary action with ADEQ on December 28, 2004. The CAO required that Timex submit a Site Investigation Report (SIR) and a Remedial Alternatives Analysis (RAA). The SIR was submitted on August 23 , 2007, and was conditionally approved by ADEQ in a letter dated December 2, 2008. The RAA was submitted in August 2011. ADEQ acknowledged receipt of the report and informed Timex and the Airport of its intent to draft a RADD on October 4, 2011.

2.1 Hydrogeological Setting The site is relatively flat and located about 255 ft. above mean sea level. Surface water/storm water drainage is primarily to the west through shallow, unlined storm drains, and ditches that discharge to a larger ditch along Bond A venue that is part of the City of Little Rock drainage system. Flow within the larger ditch continues south for approximately 1 mile and enters Fourche Creek. Fourche Creek travels east along the south side of the Site and turns north to discharge into the Arkansas River approximately 0.9 miles north of the Site.

2.1.1 Site Geology Based on information gathered during previous investigations, site geology is characterized by a surficial silt and clay unit overlying two predominant sand layers separated by a confining clay unit. The units are summarized below in descending order from the ground surface.

From the surface to 2 to 13 ft. below the ground surface, a sequence of interbedded sandy silts and clays overly the site. Thin discontinuous silty sand lenses are also present and may be associated with ancient channels. A silty clay or clay layer 2 to 4 ft. thick typically marks the base of this unit (also referred to as the 'upper clay').

A shallow sand unit, ranging in thickness from 3 to 14 ft. and consisting of reddish brown to brown silty sands and sandy silts underlies the surficial silt and clay. The shallow sand unit is underlain by a reddish-brown to brown clay that is approximately 14 to 22 ft. thick and acts as a confining unit.

The intermediate sand layer, which has a thickness ranging from 3.5 to 6ft., is located within the confining clay unit described above and consists of silt, silty sand, and poorly sorted sands. This layer is discontinuous across the Site and may represent an ancient channel deposit.

A deep sand unit of poorly graded fine to medium-grained, loose sand with a silty sand interval lies directly below the overlying clay stratum. This unit is about 35 ft. thick and extends to a depth of roughly 60 or 65ft. below grade, where it rests unconformably on the more consolidated Tertiary age deposits .

2.1.2 Site Hydrogeology Two distinct hydrostratigraphic zones have been identified at the Site: the shallow sand aquifer and the deep sand aquifer. The shallow sand aquifer corresponds to the shallow sand unit described above. Hydrogeologic conditions within the shallow sand aquifer in and around the Site vary from being completely saturated and partially confined (south) to unsaturated (north). Groundwater flow within this unit is predominantly north and northeast toward the Arkansas River, although there is a minor westward component towards Bond Avenue and another to the southeast that may be related to an ancient stream channel. Groundwater level measurements

2

indicate that groundwater is present at depths ranging from 5 to 1 7 ft. below grade. An average site-wide hydraulic gradient of 0.0064ft/ft. was calculated for the shallow sand aquifer. Hydraulic conductivity estimates for the shallow sand average 2 to 4 feet per day (ft /day). A well search did not document any current use of the shallow groundwater.

The deep sand aquifer corresponds to the deep sand layer. Groundwater flow in the deep sand aquifer is to the northeast towards the Arkansas River, which is the regional groundwater discharge point. Potentiometric surface levels within the deep sand aquifer rise to within about 14 to 18ft. of the ground surface. An average site-wide hydraulic gradient of0.00067 was calculated for the deep sand aquifer. Hydraulic conductivity estimates for the deep sand average 115 to 175 ft/day. The greater saturated thickness (35 ft.) and hydraulic conductivity ofthis zone suggests that it could be used as a water source, although municipal water is available at the Site and all surrounding areas. A well search confirmed two nearby industrial supply wells (Little Rock Crate and Basket and the former Northwest Hardwoods) screened in the deep sand, but four other wells listed in online databases could not be located and are presumed to no longer be in operation.

Groundwater elevation monitoring has suggested that there is some hydraulic communication between the two groundwater zones. Vertical hydraulic gradients between the shallow and deep sand aquifer are strongly downward, with groundwater potentiometric surface elevation differences between the two units ranging from about 6 to 9 ft. in the vicinity of the Site. The vertical gradient remains downward northeast (downgradient) ofthe Site; but the differences in potentiometric elevations between the two aquifers decrease as the distance from the Site mcreases.

2.2 Previous Investigations The Airport initially hired PMI to conduct a Phase I ESA prior to Timex ceasing manufacturing operations at the Site in 2000. The Phase I ESA identified several potential areas of concern that required further investigation and testing. The Airport and Timex retained PMI to conduct a Phase II ESA to assess the areas of concern and conduct soil and groundwater testing. The Phase II ESA included the drilling of22 soil borings in October/November 2002, to facilitate the collection of soil samples for volatile organic compound (VOC), semi-volatile organic compound (SVOC), and metals analysis.

Groundwater monitoring wells were installed in eight of the soil borings and groundwater samples were collected in November 2003 and January 2004, and analyzed for VOCs and SVOCs. This initial soil and groundwater testing identified VOCs and metals in site soils at elevated concentrations and VOCs (predominately chlorinated solvents and their breakdown products) in groundwater. A second round of soil and groundwater testing was conducted by PMI in the spring of 2004 to assess the extent of soil and groundwater impacts. That investigation was performed using direct push drilling methods and included the collection of 68 groundwater samples.

The Phase II ESA determined that past operations involving chlorinated solvents had affected groundwater quality beneath the property, but that further investigation was necessary to define the source and extent of the impact. As a result, Timex entered into a CAO for voluntary action with ADEQ on December 28, 2004. Subsequent site investigations have been performed by FTN under the CAO on behalf of Timex and included several phases with each new phase

3

building on the findings of the previous phase. In this manner, the site characterization was conducted between December 2004 and July 2008, and a site investigation report (SIR) was submitted.

In December 2007, Timex submitted the Baseline Human Health Risk Assessment (HHRA). In October 2008, Timex submitted an addendum to the HHRA for review due to EPA' s new guidance to the Association of State and Territorial Solid Waste Management Officials (ASTSWMO) regarding the appropriate toxicity factors to be used in the evaluation of risk associated with trichloroethylene (TCE) at waste sites. On December 2, 2008, ADEQ conditionally approved the SIR and included a list of concerns with the HHRA and its addendum. On February 27, 2009, a second addendum to the Baseline HHRA was submitted to ADEQ.

3.0 Summary of Site Risks A HHRA was performed to evaluate potential risk to human health and the environment. Surface soils, subsurface soils, and groundwater were sampled for the HHRA. Based on data presented in the HHRA, site-related chemicals present in on-site and off-site groundwater pose potential unacceptable risks to human health. In addition, surface water and sediment samples were collected on-site to evaluate potential ecological risk; however, these media were not identified as a potential concern at this site, as the site is situated on industrialized airport property and is not considered a suitable ecological habitat.

3.1 Chemicals of Potential Concern in Surface Soil Surface soil samples were analyzed for the presence ofVOCs, SVOCs, metals, and cyanide. Based on a comparison to the 2004 EPA Region 6 Human Health Medium-Specific Screening Levels (HHMSSLs) for residential soil, TCE, was the only chemical retained as a chemical of potential concern (COPC) in surface soils as summarized in Table 3.1a.

Table 3.1a COPC in Surface Soil

[ Trichloroethylene (TCE)

3.2 Chemicals of Potential Concern in Subsurface Soil Subsurface soil samples were analyzed for the presence ofVOCs, SVOCs, metals, and cyanide. Subsurface soils were compared to a dilution attenuation factor (DAF) of 10. Based on this comparison, several VOCs were retained as COPCs. No SVOCs, metals, or cyanide were retained as COPCs. COPCs in subsurface soils are summarized in Table 3.1 b.

4

Table 3.1b COPCs in Subsurface Soil

1, 1-dichloroethane ( 1,1-DCA) 1,1, !-trichloroethane (1 , 1,1-TCA)

1, 1-dichloroethene ( 1,1-DCE) Trichloroethylene (TCE)

cis-1 ,2-dichloroethene ( c-DCE)

3.3 Chemicals of Potential Concern in Groundwater The shallow and deep sand aquifers have been impacted by previous site activities. Currently, 62 groundwater monitoring wells have been installed on and near the Site. Ofthe 62 wells, 38 are situated in the shallow aquifer and 24 are situated in the deep aquifer (Figure 2). Groundwater flow is to the north and northeast, towards the Arkansas River.

Groundwater samples were analyzed for the presence ofVOCs, SVOCs, metals, and cyanide. Chemical concentrations detected in groundwater samples were compared to the maximum contaminant levels (MCLs) or tapwater screening levels for those chemicals that do not have MCLs. Based on this comparison, VOCs and manganese were retained as COPCs in groundwater (Figures 3 and 4). COPCs in groundwater are summarized in Table 3.2.

Table 3.2 COPCs in Groundwater

1,1, !-trichloroethane (1 , 1,1-TCA) 1 ,4-dioxane

1,1 ,2-trichloroethane (1 , 1,2-TCA) Freon 113

1, 1-dichloroethane (1 ,1-DCA) Tetrachloroethylene (PCE)

1 ,2-dichloroethane ( 1 ,2-DCA) Trichloroethylene (TCE)

1, 1-dichloroethene ( 1,1-DCE) Vinyl chloride

cis-1 ,2-dichloroethene ( c-DCE) Manganese

3.4 Chemicals of Potential Concern in Indoor Air Three indoor air quality samples were collected from both the Civil Air Patrol building and Army Reserve facility. These buildings are located approximately 130 feet northwest and 700 feet northwest, respectively, of the Site. Detected VOC concentrations were compared to 2004 EPA Region 6 HHMSSLs for ambient air. Based on this comparison, several VOCs were retained as COPCs. COPCs in indoor air are summarized in Table 3.3 .

5

Table 3.3 COPCs in Indoor Air

Civil Air Patrol Building Army Reserve Facility

1 ,2,4-trimethylbenzene Benzene

1 ,4-dichlorobenzene Chloroform

Benzene Chloromethane

Chloroform 1 ,2,4-trimethylbenzene

Chloromethane 1 ,4-dichlorobenzene

Dichloromethane (DCM)

Tetrahydrofuran

Trichloroethylene (TCE)

3.5 Chemicals of Potential Concern in Surface Water Four site-related surface water (storm water) samples and four background surface water samples were collected and analyzed for VOCs, metals, and cyanide. Results for VOCs and cyanide were non-detect in surface water samples. Several metals were detected in surface water, but at concentrations considered to be within background levels. For these reasons, no COPCs were retained for surface water.

3.6 Chemicals of Potential Concern in Sediment Data Three site-related sediment samples and three background sediment samples were collected and analyzed for VOCs, metals, and cyanide. Results for VOCs and cyanide were non-detect in sediment samples. Several metals were detected at concentrations above site-specific background concentrations. These metal concentrations were compared to their respective 2004 EPA Region 6 residential HHMSSLs for direct contact exposures. Based on this comparison, only arsenic exceeded the screening criteria; however, arsenic concentrations were within the EPA Region 6 range of typical concentrations found in this area. For these reasons, no COPCs were retained as COPCs in sediment.

3.7 HHRA Summary The HHRA considered potential health risks related to current and future human exposure to chemicals detected in soil, surface water, sediment, groundwater, and indoor air quality within the boundary of the site and groundwater located off-site. The HHRA considered potential lifetime cancer and non-cancer risks for current and future use at the site. The following risk scenarios were evaluated:

• Surface Soils: No unacceptable potential risks exist.

6

• Surface water: No unacceptable potential risks exist.

• Sediment: No unacceptable potential risks exist.

• Subsurface Soils: No current unacceptable potential risks exist. While no current potential vapor intrusion risk exists on-site, under a future use scenario, there is a potential for risk to human health resulting from volatilization ofVOCs from soil and shallow groundwater into indoor air of a future hypothetical building constructed within the footprint of the source area. To address this scenario, calculations were made to determine a remediation level in soil which would be protective of an industrial worker for the vapor intrusion pathway. A value of0.78 mg/kg TCE in soil was determined to be protective for an on-site industrial worker.

• Groundwater: Off-site- Current Adult and Child Resident: No potential unacceptable risks exist because of provided municipal water. Future Adult and Child Resident -Unacceptable potential cancer risks exist with exposure to off-site groundwater due to ingestion. On-site- Future Adult and Child Resident: Unacceptable potential cancer and non-cancer risks exist with exposure to on-site groundwater due to ingestion and inhalation.

• Indoor Air: Near off-site-Current/Future Civil Air Patrol Industrial Worker: Unacceptable potential cancer risks exist with exposure to indoor air. The current/future Civil Air Patrol Industrial Worker exceeds the cancer risk range considered acceptable by the USEPA (l.OE-06 to l.OE-04). However, according to the risk assessment, the cancer risk estimate for the Civil Air Patrol industrial worker for inhalation of indoor air is driven by 1 ,4-dichlorobenzene. 1 ,4-dichlorobenzene has not been detected in groundwater and is not considered to be associated with the Site. Excluding 1,4-dichlorobenzene, the cancer risk estimate (5.0E-06) falls within the acceptable cancer risk range.

3.8 Screening Level Ecological Risk Assessment (SLERA) Summary Surface water (stormwater) and sediment samples were collected from around the Site; however, these media were not identified as a potential concern. Furthermore, the Site is situated on airport property, and is not considered a suitable ecological habitat.

4.0 Summary of Remedial Approach The Site is currently inactive and is being maintained by Timex and the Airport. The ADEQ has determined that historical releases of hazardous substances must be addressed through remedial action to be protective of human health and the environment. Three performance standards that must be addressed are : source control, applicable statutory and regulatory requirements, and a final risk goal. The final risk goal must ensure that no unacceptable potential risks to human health or the environment remain at the site at the conclusion of remedial activities. A remedy' s cleanup standards can fall within the range of 1 x 1 o-4 to 1 xI o-6 excess lifetime risk from exposure to a carcinogenic hazardous constituent, and a hazard quotient of 1.0 for non-carcinogens. The final risk goal performance standard developed will generally fall within that range as well. The source control and statutory and regulatory requirement performance standards will determine the need for and degree of any necessary remedial actions.

7

The remedial approach for this site will use soil excavation and institutional controls as a measure to remove the existing source of contamination at the site and to ensure continued nonuse of groundwater within the contaminant plume. Contaminated groundwater will be addressed by either active remediation and/or monitored natural attenuation (MNA). Methods for remediation of the shallow groundwater aquifer are discussed below - the deep groundwater aquifer will be addressed using MNA.

5.0 Summary of Alternatives Considered The following section lists and describes the technologies considered for evaluation by the responsible party as potential technologies to be applied at the Site to meet the objectives of the remediation. This section is only a list of technologies to be further evaluated by ADEQ. Excavation of contaminated soils was the only technology evaluated for soil. A total of 24 remedial technologies were identified and screened as potential remedies for the contaminated groundwater at the Site. Of those 24 technologies, 9 were retained for further consideration. The 9 retained technologies are: soil excavation, groundwater extraction, in situ biodegradation, in situ chemical oxidation (ISCO), air stripping/activated carbon, ultraviolet (UV) oxidation, discharge to POTW, MNA and institutional controls.

5.1 Soils No Action: The No Action Alternative is one that is considered as a baseline for comparison with other technologies. Because the TCE contaminated soil may pose a potential risk to an industrial worker from vapor intrusion in the source area, the No Action Alternative cannot be justified and will not be retained for further consideration.

Excavation: Active soil remediation consisting of excavation and off-site disposal of unsaturated soils (surface and subsurface) exceeding the remedial action level (RAL) for TCE of0.78 mg/kg will be performed to mitigate potential vapor intrusion risk to future industrial workers. It is estimated that approximately 2,800 cubic yards of soil will be removed and disposed off-site. The excavation will be backfilled with imported clean fill (Figure 5). The cost for excavation and disposal of soils is estimated at $652,900.

5.2 Groundwater Excavation: Removal of contaminated soil on-site will reduce contaminant sourcing to groundwater. Costs are included under soil remediation.

5.2.1 In Situ Technologies

5.2.1.1 In Situ Biodegradation In situ biodegradation is a technique for treating contaminated groundwater in place by microbial degradation. This is accomplished by the addition of oxygen, sodium lactate and edible oil to groundwater to enhance the natural biodegradation of organic compounds by microorganisms, resulting in the breakdown and detoxification of the organic contaminants. Biodegradation has been successfully used on groundwater contaminated with VOCs and is widely used. However, depending on the type of system, biological treatment can be sensitive to a number of environmental factors, including availability of terminal electron acceptors, trace nutrients, oxygen concentration, reduction oxidation (REDOX) potential, pH, degree of water saturation, and temperature. These factors have to be monitored and may need to be controlled during

8

operation. Biodegradation is generally more effective at lower VOC concentrations(< 2,000 !Jg/L) but has been used on sites with VOC concentrations as high as those observed at this Site.

' The cost to implement this technology for the shallow groundwater aquifer is estimated at $2,652.900. In situ biodegradation will be retained for further consideration.

5.2.1.2 In Situ Chemical Oxidation (ISCO)

ISCO of contaminants in groundwater is achieved by injecting an oxidant, such as persulfate or permanganate solutions, into an injection well system or drilled open boreholes. The oxidant percolates through contaminated soils and groundwater and reacts with organic matter present producing inert compounds including carbon dioxide and water. This process would be effective for the contaminants at the Site and has been widely used at numerous sites over the last decade. The largest technical constraint is being able to inject sufficient amounts of the oxidant into the subsurface and ensuring that it is evenly distributed such that it comes in contact with the contaminants. Often several applications of the oxidant are necessary to attain remedial goals at a site. One advantage of this technology is that it is fast-acting and site remediation can be achieved in a matter of years if the oxidant can be successfully injected into targeted areas of the plume. This process is applicable to the compounds and concentrations found in groundwater at the Site and could be implemented without significant disruption to the local residents and businesses. The cost to implement this technology for the shallow groundwater aquifer is estimated at $2,319.600. In situ chemical oxidation will be retained for further consideration.

5.2.2 Ex Situ Treatment Technologies

5.2.2.1 Groundwater Extraction

Groundwater extraction (pumping) is used to prevent the migration of contaminants by controlling the groundwater flow system. This is accomplished by the installation of a series of pumping wells that are screened in the zone of contamination. The groundwater can then be withdrawn, treated on-site, and discharged. Groundwater extraction could be successfully implemented at this Site to control the migration of impacted groundwater in the shallow and deep aquifers. A disadvantage of groundwater extraction to manage migration is that such a system typically must operate for a number of years to maintain capture of the plume. It would be feasible to design and install a groundwater extraction system to provide hydraulic capture of a portion of the VOC plume for the purposes of management of migration. Given the high ICE concentrations within the source area (as high as 27,000 j.lg/L), it is unlikely that groundwater extraction would be effective at attaining the RAL for ICE in all areas of the Site within a reasonable timeframe. However, groundwater extraction will be retained for further evaluation as a potential component of a comprehensive alternative.

5.2.2.2 Air Stripping

Air stripping is the process by which VOCs in soil or water are transferred to a gaseous phase. Typically, this is accomplished by using a packed tower, shallow tray, or air diffuser. For these systems, water containing VOCs is fed through the top of the unit and flows down over the packing or through the trays as air is blown upward. VOCs (with limited solubility in water) exhibit an affinity for the gaseous phase and tend to leave the aqueous stream for the gas phase. Air stripping is commonly used as a treatment method for VOCs. Equipment for air stripping is readily available, highly reliable, can be easily designed to suit site needs, and can be quickly installed. Review of Site data indicates that the contaminants of concern (COCs) at the Site are

9

sufficiently volatile to be removed by such treatment. Air stripping often requires off-gas treatment to meet emissions standards. Air stripping will be retained as a treatment process associated with groundwater extraction.

5.2.2.3 Activated Carbon

Activated carbon adsorption is a common procedure used for removing volatile and nonvolatile organics from air or aqueous streams. In this process, the constituents are "adsorbed" by or bonded to the carbon as the stream flows through the treatment bed. Carbon adsorption is a proven and effective method of removing organics from groundwater and this technology will be retained for further consideration in association with groundwater extraction and air stripping. The cost to implement groundwater extraction and treatment with air stripping followed with activated carbon treatment is estimated at $15,259,100.

5.2.2.4 Ultraviolet (UV) Oxidation

This treatment process uses a combination of UV light and/or chemical oxidants, such as ozone or hydrogen peroxide, to break down VOCs by photochemical or chemical degradation. This method has proven effective in oxidizing organic contaminants. A typical UV -ozone/hydrogen peroxide system consists of a hydrogen peroxide feed system or an ozone generator (in conjunction with an oxygen or air source) and a UV-oxidation reactor. The UV-oxidation reactor, which is the heart of the process, provides controlled, simultaneous UV -oxidant contact. Unlike aqueous-phase activated carbon or air stripping with vapor-phase carbon, theoretically no taxies are emitted to the atmosphere or adsorbed onto media that would then require disposal or regeneration. The ultimate end products of UV -ozone/hydrogen peroxide treatment are trace salts, carbon dioxide, and water or nontoxic intermediates. The cost to implement this treatment as a follow on technology to groundwater extraction is estimated at $15,259,100. This process is a proven technology for the destruction of the VOCs of concern and will be retained for further consideration.

5.3 Disposal Technologies

5.3.1 Discharge to Publicly Owned Treatment Works (POTW) In this technology, treated groundwater is discharged into the sanitary sewer and conveyed to a POTW (i.e., sewage treatment plant). This discharge option is straightforward using conventional engineering and construction techniques. Approval would be required from the local POTW. This method of groundwater disposal is often easier than recharging treated water to the aquifer via trenches or wells because the permissible discharge limits are higher for the POTW and there is no maintenance associated with fouling. However, there is generally a sewer discharge fee charged for this service. Estimated costs to implement this technology are included with the treatment technology costs. This discharge option will be retained for further consideration.

5.3.2 Discharge to Surface Water In this technology, treated groundwater is discharged into a nearby storm sewer that drains to a local surface water body, or is discharged directly to surface water via pipe or culvert. In this case, the treated groundwater would be discharged into a local storm drain that flows from the Site to the northwest, eventually flowing into the Arkansas River. A National Pollutant

10

Discharge Elimination System (NPDES) permit would have to be obtained. Estimated costs to implement this technology are included with the treatment technology costs.

5.4 Monitored Natural Attenuation (MNA) This is a passive technology that relies on the biodegradation capabilities of indigenous organisms (reductive de-chlorination) as well as the dispersive characteristics of the aquifer material to attenuate contaminant levels. Monitoring of the groundwater is conducted to verify that contaminant concentrations are decreasing at a reasonable rate. This technology has been shown to be effective for the VOC compounds present at the Site given appropriate geochemical conditions and, as a result, will be retained for further consideration based on the evidence that natural degradation is occurring at the Site (presence of breakdown products). The cost ofMNA (both aquifers) is estimated at $314,500.

5.5 Institutional Controls Institutional controls include the use of ordinances, deed restrictions, and/or environmental easements to limit human and/or ecological exposures to contaminated media. Deed restrictions and a possible city ordinance would be utilized to prevent the use of groundwater in areas affected by Site contaminants. The Site and properties south of 1 ih Street would be limited to industrial use. They can be an effective way of preventing current and future potential risk to contaminated media and are retained for further consideration.

5.6 No Action The No Action Alternative is one that is considered as a baseline for comparison with other technologies. In the case of the Site, the No Action Alternative would preclude any remediation. The ADEQ considers all groundwater within the State of Arkansas to be a potential source of drinking water; therefore, the No Action Alternative cannot be justified and will be retained for comparison purposes only.

5. 7 Additional Alternatives Considered Numerous additional remedial alternatives were considered in the RAA. The following remedial alternatives were considered, but would not be effective or as effective as the evaluated alternatives.

• Vertical and horizontal barriers

• Permeable reactive barriers

• Air sparging/soil vapor extraction

• In Situ thermal desorption

• Ion exchange

• Reverse osmosis

• Chemical reduction/oxidation

• Chemical precipitation

11

• Aerobic biological treatment

• Infiltration (recharge) trenches

• Reinjection

5.8 Summary of Screened Technologies In this section, technology options that were retained for further consideration were selectively combined into four remedial action alternatives that are then analyzed in detail. Common to all four alternatives are excavation of unsaturated soil and institutional controls. Institutional controls are required to mitigate potential future exposures to indoor air on-site and ingestion of contaminated groundwater on and off-site.

Excavation and off-site disposal of unsaturated soils exceeding the RAL of0.78 mg/kg TCE will be performed to mitigate potential risk to future industrial workers. It is estimated that approximately 2,800 cubic yards of soil will be removed and disposed off-site as non-hazardous waste. The excavation will be backfilled with imported clean fill. The cost of the soil remediation has been included in each of the four groundwater alternatives described.

The institutional controls that will be employed include: • An ordinance from the City of Little Rock, or deed restrictions, or both limiting the use of

the impacted property(ies) south of lih Street to industrial use ("Industrial Use Institutional Controls"). 1

• An ordinance from the City of Little Rock, or deed restrictions, or both on individual parcels restricting future development of groundwater to prevent potential future human exposure to contaminants in groundwater ("Groundwater Use Institutional Controls").2

If institutional controls cannot be put into place for the required areas on-site and off-site as described, then the various remedial action alternatives will be reevaluated based on the nature of the institutional controls that can be implemented. Modifications to the selected alternative will be proposed to ensure the protection of human health and the environment. This reevaluation will be submitted to ADEQ for review and approval 45 days following notification that the necessary restrictions are not achievable.

The four comprehensive remedies developed to address the remedial action objectives (RAOs) for the Site are presented below. The objective of these remedies is to achieve soil and groundwater RALs for TCE related to impact to indoor air (0.78 mg/kg in soil and 1.96 mg/L in

1 For purposes of the Industrial Use Institutional Controls, the impacted property(ies) south of 12th Street are those that lie within the area of the shallow groundwater TCE plume emanating from 2215 Crisp Drive, and "industrial"

means current zoning as I-2 (light industrial district) as defined in Section 36-320 of the Little Rock Code of Ordinances and referenced by Amendment to Consent Administrative Order, LIS 04-206-01.

2 For purposes of the Groundwater Use Institutional Controls, the individual parcels to be covered are those that lie

within the area of the deep and shallow groundwater TCE plumes emanating from 2215 Crisp Drive.

12

shallow groundwater) on-site through active treatment and to achieve the MCLin shallow groundwater off-site and in deep groundwater in all areas of the plume, following monitored natural attenuation. The four alternatives are as follows:

Alternative 1 -Monitored Natural Attenuation (MNA): This alternative would rely solely on natural processes for remediation of contamination in the shallow and deep groundwater aquifers. RAOs would be addressed by the implementation of institutional controls to prevent exposure pathways via ingestion of contaminated groundwater and inhalation of vapors from soil and/or shallow groundwater. Excavation would be implemented to address unsaturated soils exceeding the RAL of0.78 mg/kg TCE.

Alternative 2 - Groundwater Extraction and Treatment of Shallow Source Area Groundwater: This alternative would include groundwater extraction from the shallow aquifer south of 12th Street, treatment on-site, and discharge to the local POTW. Shallow groundwater would be treated to meet the RAL of 1.96 mg/L TCE on-site. Excavation would be implemented to address unsaturated soils exceeding the RAL of0.78 mg/kg TCE. MNA would be implemented for the deep groundwater both on-site and off-site to meet the RAOs for the Site. Institutional controls would be implemented for the shallow and deep groundwater on-site and off-site. The following two options are considered for Alternative 2 based on the treatment method:

(A) Option A- Air Stripping/Vapor Phase Carbon Adsorption

(B) Option B - UV Oxidation

The contaminated groundwater would be extracted via continual pumping from wells placed in such a way as to capture shallow groundwater exceeding 10 mg/L total VOCs to reduce the overall contaminant mass and reduce contaminant loading to the deep groundwater. Extracted groundwater from all recovery wells would be combined and treated on-site. Under treatment Option A, the water would be treated by a multi-stage air stripper to remove the VOCs. Air emissions would be controlled using vapor-phase activated carbon. Under treatment Option B, the water would be treated via a UV /oxidation system, employing UV lamps and the addition of hydrogen peroxide. Under both options, treated groundwater would be discharged to the POTW under a permit.

Alternative 3 -In Situ Chemical Oxidation (ISCO) of Shallow Source Area Groundwater with An Appropriate Oxidant: This alternative would involve ISCO via injection of an oxidant (such as activated persulfate or permanganate solutions) into the shallow groundwater using direct-push technology to meet the RAL of 1.96 mg/L TCE on-site. The oxidant will react with and destroy the VOCs, producing only inert byproducts. Excavation would be implemented to address unsaturated soils exceeding the RAL of0.78 mg/kg TCE. MNA would be implemented for the deep groundwater on-site and off-site. Institutional controls would be implemented for the shallow and deep groundwater on-site and off-site to meet the RAOs for the Site.

Alternative 4 -Enhanced In Situ Biodegradation of Shallow Source Area Groundwater: This alternative injects nutrients, in the form of sodium lactate and edible oil , into the shallow groundwater using direct push technology to stimulate indigenous bacteria, thereby enhancing

13

the natural biodegradation of the VOCs. Inoculation of the subsurface with additional bacteria would be performed to expedite the treatment. Excavation would be implemented to address unsaturated soils exceeding the RAL of0.78 mg/kg TCE. MNA would be implemented for the deep groundwater on-site and off-site. Institutional controls would be implemented for the shallow and deep groundwater on-site and off-site to meet the RAOs for the Site.

6.0 Proposed/Recommended Remedies The proposed remedies are final following a thirty (30) day public comment period and appear in Section 10.0 ofthe RADD.

7.0 Evaluation of the Proposed Remedy and Alternatives Each remedial alternative was evaluated on the following criteria: Overall protection of human health and the environment, short term effectiveness, long term effectiveness, implementability and cost. Please see Table 7.1 for a comparison of the remedial alternatives.

8.0 Remedial Action Levels Remedial Action Levels (RALs) are site-specific risk-based clean-up levels calculated for the

protection of human health and the environment, which take into account potential receptors, exposure routes, and institutional controls. RALs in this RADD are based on chemical concentrations in on-site and off-site groundwater greater than the maximum contaminant level (MCL) and potential vapor intrusion risks due to concentrations of volatile organic compounds in on-site subsurface soils and shallow groundwater.

14

Table- 7.1: EYaluation of Remedial Alter·uatirYes Selection Criteria

R.ellledial Alternative Effeo1ivenes'

Protection of H:lJllrul He-<ilih. and the Short Long~ Implementability En'!.iTroillJ.1eDt term term_

C'..osl

!ExC\.~tion.ofTCE Soil abo-..·e 0.78ppm

J.tl:onitored l\ atuml Attenua.tion

will help reduce ICE migrati.on into grounm\·ate.r

med to ensure the plume bound.1J)' i~ stable

Grm.mmvater Ehirad ion :md Treatment in Shallo\\1 lwill reduce and conrol the sbailo\v Source P....rea aquifer TCE plume

In-Situ Chemical Oxidation in Shallow Grounmv:J~ter I will effecti\·ely reduce the shallmv Source .1\rea aquifer TCE plume

Institutional Comrols foT Grmm®ra.ter t:se will work ~ a legal m.ech..11lism to prevent contact with contaminated grounmv:J~ter

Enh. ·ID r oed .. In-Situ Biodegrndation in Shallow Somce 1\vill effect.J ·vely reduce the· &hallow }\rea aquifer TCE plume

~o F1-trther Action

Total Co:st for Sfile-cud Remedit-s

disreg.mis impact to hmnm health :md the em.rrOlllllenl

note: highlighted! rmvs represent rem.edia] altematives tbat have been ~leered by ADEQ

15

yes

yes

yes

ves

yes

yes

\\ill require a work plan and IS652 900 )"eS I ' +tin a '

penm,~

, monitoring well nenvoik is already 1 S 314 '00 } es. I establi;:hed ' J

, '"ill not be effective in attaining fue ISB,259,100 yes I PRG in a rearonable blll.e frame

, "eS fast acting. but . it is difficult to IS 1 1 19 600 J le,·ertlydistribute the oxidant -·- ·

res. I requires coordination with cit-, and oonm:runity

1 IVnlmo<\n

this tedmol~· can be sellSll.tive tol"-; 65) 800 'eS I --::,.; Jl' ~, ...., } emrir0lllllell1al mcton

no 1 no 1 ea:.y' to imple:w.ent $0

$3.287,00(11

8.1 Soil Remedial Action Levels

The following table summarizes remedial action levels for soils at the Site.

Table 8.1 Remedial Action Levels for Soils

Surface Soil Subsurface Soil Chemical Remedial Action Remedial Action

Level (mg/kg)(I) Level (mg/kg)<2>

1, 1-dichloroethane (1,1-DCA) NAtJJ 0.0068

1, 1-dichloroethene (1 ,1-DCE) NA<3> 0.025

cis-1 ,2-dichloroethene ( c-DCE) NA<3> 0.21

1,1, !-trichloroethane (1 , 1,1-TCA) NA<3> 0.70

Trichloroethylene (TCE) 6.4 0. 78(4)/0.018

(1) =Based on the USEPA Industrial Soil Screening Level (November 2011) (2) =Subsurface Remedial Action Levels based on a DAF 10 (3) =Not Applicable- Chemical was not detected above screening level in surface soil (4) =TCE concentration protective for future on-site industrial worker via vapor

intrusion

If the Industrial Use Institutional Controls and Groundwater Use Institutional Controls (as described in CAO LIS 04-206-01 , paragraph 6(A)(i) and (ii) and Section 5.8 ofthis RADD) are implemented on the Site, a subsurface soil remedial action level of 0. 78 mg/kg for TCE will be used. If institutional controls cannot be put into place as described, then the various remedial action alternatives will be reevaluated based on the nature of the institutional controls that can be implemented. Modifications to the selected alternative will be proposed to ensure the protection of human health and the environment. This reevaluation will be submitted to ADEQ for review and approval 45 days following notification that the necessary restrictions are not achievable.

8.2 Groundwater Remedial Actions Levels The following table summarizes remedial action levels for on-site and off-site groundwater.

16

Table 8.2 Remedial Action Levels for Groundwater

Chemical Remedial Action Level

(ug/L)

1,1, !-trichloroethane (1 , 1,1-TCA) 200

1,1 ,2-trichloroethane (1,1,2-TCA) 5.0

1, 1-dichloroethane (1,1-DCA) 2.4(1)

1 ,2-dichloroethane (1,2-DCA) 5.0

1, 1-dichloroethene (1 ,1-DCE) 7.0

cis-1 ,2-dichloroethene (c-DCE) 70

1,4-Dioxane 0.67(l)

Freon 113 53 ,000(I)

Tetrachloroethylene (PCE) 5.0

Trichloroethylene (TCE) 5.o (1 ,96oP)

Vinyl chloride 2.0

Manganese 50(2)

(1) = USEPA Tapwater Screening Level (MCL Unavailable) (2) =Secondary Drinking Water Standard (3) = RAL for shallow groundwater on-site only

If the Industrial Use Institutional Controls and Groundwater Use Institutional Controls (as described in Section 5.8 of this RADD) are implemented, a groundwater remedial action level of 1,960 flgfL for TCE can be applied to the on-site shallow groundwater. However, if institutional controls cannot be put into place for the required areas on-site and off-site as described, then the various remedial action alternatives will be reevaluated based on the nature of the institutional controls that can be implemented. Modifications to the selected alternative will be proposed to ensure the protection of human health and the environment. This reevaluation will be submitted to ADEQ for review and approval 45 days following notification that the necessary restrictions are not achievable.

17

9.0 Justification for Selections The following media specific remedies incorporate the application of institutional controls which limit use of impacted properties over the shallow plume to industrial uses and prevent the use of shallow and deep groundwater on-site and off-site within the area affected by the groundwater contamination. These restrictions are integral to the remedies selected.

9.1 Soils Although other technologies are available for the treatment of unsaturated soils containing VOCs, the limited extent of the soil contamination requiring remediation and the open and accessible nature of the Site make excavation with off-site disposal the obvious alternative. Because the TCE contaminated soil poses a potential vapor intrusion risk to a future industrial worker should a building be placed over the source soil area, the No Action Alternative cannot be justified and will not be retained.

9.2 Groundwater An ordinance from the City of Little Rock, or deed restriction, or both on individual properties restricting future development of groundwater within the plume will prevent potential future exposures to contaminants in groundwater. Active remediation using ISCO will be performed on the shallow aquifer to treat groundwater contamination on-site exceeding the RAL of 1.96 mg/L TCE to address future potential risk to indoor air as a result of volatilization ofVOCs from shallow groundwater. This option will reduce contaminant mass within the shallow groundwater and achieve the RAL for TCE for volatilization to indoor air in the timeliest manner possible and with the least impact to potential site development.

If the ordinance from the City of Little Rock, or deed restriction, or both on individual properties restricting future development of groundwater within the plume cannot be achieved, written notification must be submitted to ADEQ stating the needed deed notices are not achievable and the remedial technology will be reevaluated based on the nature of the institutional controls that can be implemented. Another technology may be selected to ensure the Site RAOs are met under the achievable restrictions. The technology selected must be submitted for review and approval by ADEQ 45 days following notification that the necessary restrictions are not achievable.

10.0 Selected Remedy/Site Plan The remedial alternatives are selected to meet the Site RAOs. The following media specific remedies incorporate the application of institutional controls which limit site use to industrial and prevent the use of shallow and deep groundwater on-site and off-site within the area affected by the groundwater contamination. These restrictions are integral to the remedies selected.

For soil: Excavation- Active soil remediation consisting of excavation and off-site disposal of unsaturated soils exceeding the RAL of 0. 78 mg/kg of TCE will be performed to mitigate potential vapor intrusion risk to future industrial workers. It is estimated that approximately 2,800 cubic yards of soil will be removed and disposed off-site. The excavation will be backfilled with imported clean fill.

18

For the shallow groundwater aquifer on-site: ISCO of Shallow Source Area Groundwater with an oxidant (ie. activated persulfate )-ISCO via injection of a site-appropriate oxidant into the shallow groundwater using direct-push technology will treat groundwater contamination in the shallow aquifer exceeding 1.96 mg/L TCE. The oxidant will react with and destroy the VOCs, producing only inert byproducts. Following active treatment, Timex may transition to monitored natural attenuation subject to ADEQ approval.

For the deep groundwater on-site and off-site: This alternative relies solely on natural processes for remediation of contamination in the shallow and deep groundwater aquifers. The plume exhibits signs of natural degradation with the presence of daughter products such as DCE. For all groundwater remedies, attainment ofthe MCL is the ultimate cleanup goal. An ADEQ approved groundwater monitoring plan with details for well selection, parameters, and sampling frequency will be required for implementation.

11.0 Financial Assurance Financial Assurance will be required for the total estimated cost of corrective action for a minimum 30 year period utilizing the current cost estimates. This estimated cost must include all

ofthe remedial options presented in Table 7.1. Within 60 days ofthe date of the Final RADD, a

financial assurance mechanism must be in place which adheres to APC&EC Regulation No. 23 §265.143. The cost estimate and the financial assurance mechanism should be updated annually subject to approval of ADEQ.

12.0 Effectiveness Monitoring Program An effectiveness monitoring program includes several elements to measure the remedy against

the RAOs.

• An access agreement must be in place to allow the responsible party to implement the remedy. A signed copy of this agreement must be submitted to ADEQ within 30 days of the effective date ofthe implementing CAO.

• A detailed schedule to include submittal of a groundwater monitoring plan, treatment technology pilot test work plan, each to include a schedule for implementation, should be submitted to ADEQ for review and approval within 60 days of the effective date ofthe implementing CAO.

• All necessary deed notices will be filed for the properties within 120 days from the effective date of the implementing CAO. File marked copies of the notices will be

submitted to ADEQ within 30 days of the filing. If institutional controls cannot be put into place for the required areas on-site and off-site as described, then the various

remedial action alternatives will be reevaluated based on the nature of the institutional

controls that can be implemented. Modifications to the selected alternative will be proposed to ensure the protection of human health and the environment. This

19

reevaluation will be submitted to ADEQ for review and approval 45 days following notification that the necessary restrictions are not achievable.

• If groundwater monitoring results indicate the active remedial actions taken on-site are not effective as demonstrated by meeting the RAL for on-site groundwater or a significant decrease in constituent concentrations after 5 years of monitoring, additional remedial actions (which may include additional on-site treatment) will be required. A plan for the additional remedial evaluation and activities will be submitted for review and approval 45 days following notification from ADEQ that the current remedy is not effective.

13.0 Community Participation A community relations plan should be submitted to include:

• Direct notice to impacted landowners and tenants describing the extent, chemical properties, and potential risks of exposure to persons known to work or reside within defined areas known to be contaminated; describes source control measures or remedies to be implemented;

• A mechanism to keep impacted landowners and tenants informed throughout the duration of the project;

• A letter of Notification of Contamination be sent to potentially impacted landowners and provide notification by Registered mail within 30 days of the effective date of this RADD; and

• A schedule to submit copies of letters and mail receipts to ADEQ within the remedial time frame to demonstrate completion of these tasks.

The administrative record for the Former Timex Property may be reviewed at:

Arkansas Department of Environmental Quality 5301 Northshore Drive North Little Rock, AR 72118

14.0 Coordination with Other Divisions/Agencies It is important to involve and/or inform other divisions of ADEQ and other agencies as applicable, in the development of a RADD. To keep EPA informed of all remedial action work, EPA Region 6 was provided a copy of the Public Notice and RADD for review and comment.

20

INTERNAL COORDINATION

ADEQ Divisions Consulted/Informed Sent Notice of Decision

Water No Yes

Air No No

Solid Waste No No

Regulated Storage Tanks No No

Environmental Preservation And No Yes Technical Services

Mining No No

EXTERNAL COORDINATION

· Other State and Federal Consulted/Informed Sent Notice of Organizations Decision

U.S. EPA, Region 6 Yes Yes

AR Office of Emergency Services No No

AR Dept. of Health No Yes

AR State Clearinghouse No No

AR State Historic Preservation No No

AR Natural Heritage Commission No No

AR Game & Fish Commission No No

U.S. Army Corps of Engineers No No

The RADD was also sent to all applicable branches of the Hazardous Waste Division, and to all divisions and agencies as noted above.

21

APPENDIX A

FIGURES

22

0 500

W+E s

FIGURE 1: SITE LOCATION Former Timex Facility

Little Rock National Airport Little Rock, Arkansas

D D ~

f/g; aO

c:::J

____ ..:J..':\"@""' Choctaw,lnc.

ij a

CJ c::l CJ

D

0 ...,. lftlliT_

~430' D

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t:l 0 l D~ cu

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~ 0 0 0

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/ WW-315!

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/ WW-32

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loi-~W~~ 11MU F.ACJUn'M@2 (f) ww-..o

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+ FIGURE 2:

SITE LAYOUT

Former Timex Facility Little Rock National Airport

Little Rock, Arkansas

c:::J

~\"'@""'

+ FIGURE 3:

THE DISTRIBUTION

OF TCE IN SHALLOW

SAND AQUIFER



oW • i,lg;

C::J

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~0 0 0

aCJ CJ C;] CJ

\ \

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'\. MW-49D~(ft}WW-4iS ......,.,

'-.. --......_ __ _

+ FIGURE 4:

THE DISTRIBUTION OF TCE IN DEEP SAND

AQUIFER



----- ----- -----

MW-34D

~ MW-345

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MW- 135

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ALLEY

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~ ,f>~ s

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@ MW-28

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MW-21 MW-22

CHAIN-LINK FENCE

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MW-41D

@ ~ ,f>~

@ STORM DRAIN @ @MW-23

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MW-10~ FORMER TIMEX FACIUTY MW-1DS @MW-12

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CENTRAL FLYING SERVICE

_./q,

CHAIN-LINK FENCE

CENTRAL FLYING SERVICE

""""""

STORM DRAIN

PI.Nol tllJIM]) f'MIM P\.A/01 [Mlln.fil .,ORWDII 1WDI fACUTY, UTliL MlOI: N .. 110N#L......-oltl,UlllL~~I.U[!Ur",IYFlNASSOC.llD .. SCirU:l"•loti',OAT£0;0111/25/2001.

+

~ ,f>~

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....,., ww-ot(i WONTORioiGl 'fiiEll.

EJm:NT OF SOLS EXc::aDINC TCE PRC OF 0.78 t.IG/I(G

-""' .. . . . .

FIGURE 5: EXTENT OF SOILS

EXCEEDING RALs FOR TCE

Former Timex Facil ity Little Rock National Airport


et seq., et seq., - arkansas times · previously operated by timex corporation (hereinafter...

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