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• Explanation of Significant Di N,WfllC Site 19, On-Shore Derecktor Shlpya (OU 12)

Naval Station Newport, Rhode land Incorporation ofSite 4 Groundwater Into Site 19 tShore

INTRODUCTION AND STATEMENT OF PuRPOSE

An Explanation of Slgriflcant Differences (ESD) Is required for Site 19, On-Shore DerecktDr Shipyard, Naval Station (NAVSTA) Newport, Rhode Island. Site 19 On-Shore Is dasslfled as Operable Unit (OU) 12. This ESD modifies the 2014 Record of Decision (ROD) by lncx,rporating Site 4 Into OU 12 and adding remediation of Site 4 groundwater Into the groundwater response actions for Site 19 groundwater. The eso also adds a determination that No Action Is required for soi within Site 4. The modification Is significant because it expands the limits of Site 19 to lndude Site 4 and it also adds chromium as a chemical of concern (COC). 1hese changes do not fundamentally alter the overall cleanup approach documented in the Site 19 onshore ROD.

The Navy Is the lead agency, with oversight from the United States Environmental Protection f,(Jency (EPA) and Rhode Island Department of Environmental Management (RIDEM), for cleanup of sites at NAVSTA Newport In the Installation RestDratlon Program (IRP) under the Comprehensive Environmental Response, Compensation, and Uabllty kt. of 1980 (CERQ.A) as modified by the 5uperfu,d Amendments and Reauthorization Pd of 1986.

The OU 12 ROD for Site 19 On-Shore was signed by the Navy on September 12, 2014 and signed by EPA on September 14, 2014. The Navy Is Issuing this ESD as part of the public participation requirements under Section 117(c) of CERCLA, Section 300.43S(cX2)(1) of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and the Navy IRP. In aa:ordance with Section 300.82S(a)(2) of the NCP, this ESD will become part of the Administrative Record for the facllty. The Administrative Record also contains background Information that was used in determining the selected remedy, as documented In the ROD, and In preparing this ESD. The Administrative Record for NAVSTA Newport 1$ induded as part of the Information RepositDry, which is available for review at the following web site: tlttp://go.usa.gov/DyNw.

SITE HISTORY, NTAMINATION, AND SELECTED R!M!DY

Derecktor~5i· ardSite 19, the Fo er Oerecktor Shipyard, Is located at c.oddlngton In the central portion of NAVSTA Newport, and es land within both Mlddetown and.Newport. I~mmposed ofapproximately 41 acres ofshorell land and Improvements and the adjacent deep r Industrial port In Coddington COve that were rmertv leased to Robert E. Oerecktor Shipyards of; Island, Inc. (Derecktor, Inc.).

C.Ontamlnants In II and groundwater were identified during past envl I nmental assessments at the Former Derecktor Shlpy~rd and were attributed to previous activities, malnl~Ithose actlvtt;les undertaken by Derecktor, Inc.~lr, maintenance, and construc:tlon of private and ltary ships), during their lease period rrom 1979 throu h 1992. The ROD desalbed the selected remedy for soll and groundwater at Site 19. Toe soil remedy ncludes soil mver and land use controls (WCs) and the selected groundwater remedy consists d m:tred naual attenuation (MNA) and LUCs. The se remedy for Site 19 On-shore also Includes ccndudlna five-year reviews. There was a separate ROD a~d-there are separate ongoing response actio~!or Sile 19 Off-shore (OU 5), which Is unaffected by ~L ESD. Groundwater COCs identified In the ROD Include: Trichloroethene,), Vinyl Chloride, Arsenic, Cobalt, Iron, and Mang ese. The remedial goals (RGs) lnduded In the lte 19 On-shore ROD for these COCs are listed In the t table ilcluded within this ESO.

Codington Co'f Rubble RI/Area The c.odlngtoni Rubble FIii Area, Site 4, is an 8­acre vegetated rea located adjacent to the southeast of Site 19. From 1978 to 1982, Site 4 was a disposal area for inert .ble fill including conaete, asphalt,

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metal, slate, 7.; brush, etc. In August 2014, a,

Study Screening Area Evaluation report was flnahzed, documenting no action for sod (Including rubble fill), sediment, and s rface water, but with the recommendatl to further assess arsenic, chromium, cobalt, iron, and manganese in groundwater. In Apil

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2016, a Supplemental Groundwater Evaluation Report concluded that that arsenic il groundwater at Site 4 exceeded the federal maximum contaminant level (MCL) during multiple sampling events and requires a response action.

BASIS FORTHE DOOJMENT

Based on the slmllarlty of groundwater a:,ndittons at Sites 4 and 19 and their proximity to each other, the Navy, EPA, and RIDEM agreed to Incorporate Site 4 Into OU 12; determining no action Is required ror Site 4 soll, sediment or surface water; and adding remediation rlSite 4 groundwater Into the groll1dwater response actions for OU 12, The expanded groundwater area that Incorporates Site 4 Into the Site 19 groundwater LUC, MNA and long·term monitoring (LTM) program Is shown on Figure 1.

DESCRIPTION OF SIGNIFICANT DIFFERENCES

Through this document Site 4 wlU be incorporated Into 0012. The Supplemental Groundwater Evaluation Report documents that groundwater LTM parameters for Site 4 will be limited to the five metals Identified as conb'ibutlng to potential risks (arsenic, chromium, cobalt, iron, and manganese). These five metals overlap with the Site 19 COCs, with the exception of chromium. Per this ESD, groundwater at Site 4 will be inmrporated lntD the Site 19 On-shore MNA remedy and LTM program. Groundwater at Site 4 will be required to achieve Site 19 deanup levels Included In the ROD. ln addition, groundwater at Site 4 will also be required to meet a groundwater cleanup level of 100 µG/L for chromium, which Is the federal MCL Refer to the Inset table for a summary of COCs and R.Gs for the expanded OU12 On-shore MNA and LTM program.

C1emlcal ofconcern Remedfal Goal (me\ CRGl. uG/L

TCE 5

I Vinyl Chloride 2

Arsenic 10

I Cobal: 4.7

Iron 11,000

Manganese 300

Chromium• 100

ma: • Additional coc for groundwater to lnc:arporate Site 4 Into the Site 19 grcM6Nater response actions. Only •1es to Site 4 area and portions of Site 19 located downgradient rl Site 4.

The Navy has evaluated the groundwater attenuation factors evaluated ror Site 19 and determined that the MNA analysis used for Site 19 are also applicable to

Site 4. The g ter LTM parameters for Site 4 indude arsenic, <;hromlum, cobalt, Iron, and manganese. MNA Is expected to be successful because of the relatii levels of contamination and their susceptibility to eochemlcal d1anges In the aquifer that OCC\I', The avy will assess groundwater at Site 4 to analyze •The available site data indicate that MNA will be ~Iover tfme, amntly estimated at 30 ~".5 ~metals. The time required will be re-evalua~ed In the Ave-Year reviews for NSN. A monitoring ~ram wlll be developed for Sites 19 and 4 that will ?flflrm that the expected attenuation

=n:a=ratH~a::b~=1 =h::ln

the ·ou12 RO=llatlon cl monitoring wells and other graundwa,.- remedial Infrastructure needed to Implement ~endwater remedy within Sib! 4 will meet the ARARs ulrements Identified in the OU12 ROD. The cost of Implementing an MNA remedv at Site 415 $ 628,897 more than the $ 2,231,900 cost~the OU 12 ROD remedy which Is an approximate 2 increase.

The rurrent and nticipated future use ofgroundwater In Site 4 and.S~~19 are the same. Therefore, the groundwater L~ for Site 19 will also be applied to Site 4 and will ~ documented in arevised LUC RD for Site 19. These Lt/";5 prohibit lnstallatlon of groundwater suPp!Y wells, lnduding public and private drinking water wells and resldentlal Irrigation wells, and prohibit u~groundwater until groundwater deanup stand are achieved•.The Site 19 soil WC will not extend Site 4,I

This change to;the selected remedy will still be protective of h an health and the environment as presented In the ROD, and with regard to the incorporation of ~ 4 Into OU 12 as documented In this ESD. I

SUP,RT AGENCY COMMENTS

EPA and RIOEM representatives, as part of the NAVSTA New!'IRTeam, have had ongoingInvolvement In e decision-making process associated with this new fin ing and subsequent change In the OU 12 selected edy. The Navy has obtained concurrence 3RIDEM on the modification to the selected remedy for OU 12 as desoibed In this ESO.

Sr~1u110RY DETERMINATIONS

The Navy ~edgesthe Incorporation of remediation ofi:4 groundwater Into the response actions for OU 1 •The remedy documented In the 2014 ROD, whl i Includes MNA and LUCs, Is an appropriate res~se action for groundwater contamination at Site 4. No action is required for soil, sediment, or s ce water within Site 4.

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The scope, performance, and cost of the remedy are not slgnlfk:antly altered by the Incorporation of groundwater at Site 4. There Is no significant change to any other c:omponent of the remedy. The proposed change to the selected remedy wiU continue to satisfy the statutory requirements of CERa.A Section 121, and the modified remedy will remain protective of human health and the environment and will continue to comply with federal and state ARARs and to be cost effective.

Pusuc PARTICPATION

Public participation ll!ClUlrements as outlined In the NCP, Section 300.435 (c) (2) (I), have been met by lncluclng this ESD In the Administrative Record for Site 19 and by publishing in local newspapers a notice of avallablHty of the ESO within two weeks of regulatory concurrence on the dOCJment. In addition, the Navy regularly meets to dlsa.ass ttle status and progress of the IRP with the Restoration Advisory Board (RAB), which Includes representatives from the local community. Representatives from the Navy, EPA, and RIDEM attend these meetings. The Incorporation of Site 4 groundwater Into the groundwater response actions for Site 19 was dlso ISsed at the RAB meeting on July 20, 2016.

foR MORE INFORMATION

rt you have questions or would llke further Information about the ESD for Site 19 at NAVSTA Newport, please contact:

Ms. UsaRama Publtc Affairs Office

690 Peary Street Naval Station Newport

Newport, RI 02841·1512 401-841·3538

Ms. Kymberlee Keckler Remedial Project Manager

U.S. Environmental Protec.tlon Agency, Region 1 S Post Office Square, 5uite 100

Mall C.ode: OSRR07·1 Boston, MA 02109-3912

Telephone:617-918-1385 E-mall: Kedder.Kymberlee@epa.gov

Ms. Pamela Crump RIDEM Project Manager

Rhode Island Department of Environmental Management

235 Promenade St Pn:wldence, RI 02908-5767

Telephone: (401) 222·2797 ext. 7020 E-mail: pamela.aunp@dem.rt.gov

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DECLARATION

Site 4 groundwater, which Is contaminated with metals, will be added to the rem for Site 19 groundwater, which Includes monitored natural attenuation and land use controls. Therefore an ESD the 2014 ROD Is needed to document the expansion of the limits ofSite 19 to Include groundwater at Site 4 a d to add chromium as a chemlca1 ofconcern. For the foregoing reasons, by my signature below, I approve the Is of this Explanation of Significant Difference for the Record of Decision for Site 19 at NAVSTA Newport. J

UnitedStates Department ofthe Navy: United Statm Envll nmental Protection Agency: r

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U.S. EPA Region 1

Bryan 0. 0 Director Office ofSite Remediation a

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PNdonct loland

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Legend

0 Monitoring w.11Location

0 Unverified Monitoring Well

L:JInitial On-Shore Site Boundary

L:JExpanded On-Shore Sttt Boundary

C=:J Existing Slruelure

~ Railroad Tracks

FIGURE 1N

A EXPA DED GROUNDWATER AREA

SITE 119 - DERECKTOR SHIPYARDDrawn: JB 0 175 350 ONSHORE AND OFFSHOREApproved: MK 08/11/2016 Scale in Feet

NAVST. NEWPORT, RHODE ISLANDProject#: 60436343

II RHODE ISLAND

DEPARTMENT OF ENVIRONMENT L MANAGEMENT - a 235 Promenade Street, Providence, RI 02908,5767 TDD 401,222-4462

15 Septembe1· 2016

Bryan 0. Olson, Director U.S. EPA, Region I Office ofSite Remediation and Restoration 5 Post Office Square Suite 100 (OSRR 07-5) Boston, MA 02109-3912

RE: Site 19 - On-Shore Derecktor Shipyard Naval StationNewport, Rhode Island

Dear Mr. Olson:

The Office ofWaste Management has conducted a review ofthe &p/a.zation ofSig11i.ficant Differences (ESD), dated August 2016, for Site 19-On-Shore Derecktt>r Shipyard, Naval Station Newport, Rhode Island. The BSD documents the expansion offhe limits ofOn-Shore Derecktor Shipyard to include the groundwater from Site 4- Coddingtqn Cove Rubble Fill Area. It also adds chromium as a groundwater chemical ofconcern•. Af a result ofthis review, the Department concurs with this BSD. . ,

Ifyou have any questions, please feel free to contact MatthewDeStefano ofmy staff at ( 401) 222-2797, extension 7141.

Sincere_!:, ,,, /

,;,:./YAV Leo Hellested, P.E., Chief Office ofWaste Management Dept. ofEnvironmental Management

cc: Matthew Destefano, RIDEM Pamela Crump, RIDEM Anni Loughlin, US~P A Kymberlee KeckJer, USEPA Jim 01'avette, NAVFAC MIDLANT

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