40 Shattuck Road | Suite 110

Andover, Massachusetts 01810

www.woodardcurran.com

T 866.702.6371

T 978.557.8150

F 978.557.7948

Via Electronic Mail

July 13, 2018

Ms. Anna Krasko Mr. Paul Kulpa Remediation Project Manager Senior Environmental Scientist USEPA – New England Region OSRR, NH and RI Superfund Section

Rhode Island Department of Environmental Management

5 Post Office Square, Suite 100 235 Promenade Street Mail Code OSRR07-1 Boston, MA 02109-3912

Providence, RI 02908

Re: OU 2 RI/FS Implementation L&RR Superfund Site North Smithfield, Rhode Island Reporting Period: April 1, 2018 – June 30, 2018

Dear Ms. Krasko and Mr. Kulpa:

This quarterly progress report is submitted to the U.S. Environmental Protection Agency (USEPA) and Rhode Island Department of Environmental Management (RIDEM) documenting activities completed during the above referenced period for which implementation of the Remedial Investigation/Feasibility Study (RI/FS) for Operable Unit 2 (OU 2) of the L&RR Superfund Site remains on-going. Quarterly progress reports are submitted in accordance with Section IX. 51 to the Administrative Settlement Agreement and Order on Consent (AOC; effective date August 17, 2015).

1.0 Quarterly Work Summary

• Comments were received from USEPA and RIDEM on April 4, 2018 regarding the 2018 Pre- Record of Decision (Pre-ROD) Sampling Event Work Plan, previously submitted on March 30, 2018. Select comments were discussed during a conference call with USEPA and their oversight contractor, AECOM, on April 10, 2018. Additional comments were received electronically from USEPA on April 23, 2018. A revised version of the 2018 Pre-ROD Event Work Plan was submitted on June 7, 2018. This submittal was followed by a subset of additional comments from RIDEM, and responses were provided via email on June 21 and July 3, 2018, respectively.

• Collection of residential drinking water samples on April 11, 2018 as part of on-going semi-annual activities. Analytical results were reviewed and validated and incorporated into draft results letters provided to USEPA on May 21, 2018 for distribution to residents.

• Submittal of a work plan on May 14, 2018 for advancement of an additional borehole north of existing borehole BH14-1 to address data gap concerns. This work plan was preceded by discussions with AECOM. Work plan approval was received on May 23, 2018.

• Review of parcel ownership and evaluation of access routes to the proposed northern borehole/well locations. Access under the existing agreement with the Town of North Smithfield was coordinated during correspondence on June 20, 2018.

• During the April 10, 2018 conference call with USEPA and AECOM to review comments associated with the 2018 Pre-ROD Event, the discussion also included collection of additional samples for Per- and Polyfluoroalkyl substances (PFAS) analysis. A Work Plan

L&RR Superfund Site (229620.01) 2 Woodard & Curran QSR-09 Quarterly Summary Report July 13, 2018

for Additional Sampling of PFAS was submitted on May 14, 2018 and followed by comments from USEPA on May 23, 2018. A Work Plan Addendum, including a comment response, was provided on June 22, 2018.

• Residual soil/rock cuttings and groundwater were managed on-site between April 3-4, 2018 using procedures outlined in the Investigation Derived Waste Management and Recommendations submittal, provided to USEPA and RIDEM on September 5, 2017, which was developed based on RIDEM Regulations. This involved distribution of 53 drums of soil and rock cuttings within the ruts along the landfill access road and on-site treatment of groundwater using granular-activated carbon prior to upgradient discharge on the landfill surface.

• Submittal of the Interim Final version of the Screening Level Ecological Risk Assessment (SLERA) and Refinement report on May 4, 2018. This version of the report incorporated comments received from USEPA and its contractors during the previous quarterly status period. During development of the tables and supporting narrative associated with “Comment No. 10” to the January 19, 2018 comment review document for Addendum No. 2 to the SLERA and Refinement, select changes to the identification of contaminants of potential ecological concern (COPECs) in the May 4, 2018 Interim Final SLERA and Refinement report were required. A revised version of the SLERA and Refinement was provided on June 30, 2018.

• Resources to support USEPA’s evaluation of ecological risks as part of “Comment No. 10” to the January 19, 2018 comment review document were submitted on June 30, 2018.

2.0 Problems Identified and Response Actions Taken

• None to report during this reporting period.

3.0 Out of Scope Work

• None to report during this reporting period.

4.0 Status of USEPA/RIDEM Action Items from Previous Quarterly Report

• None specific to Quarterly Status Report No. 8.

5.0 Data and Results

• Following the distribution of PFAS results to USEPA and RIDEM on March 29, 2018, correlation plots involving PFAS and 1,4-dioxane were provided on April 12, 2018 to support USEPA’s review of the PFAS results.

• Residential well sampling data for individual properties were provided on May 21, 2018 along with a summary of all residential well results to date.

6.0 Planned Work for the Next Quarter

• Drilling of the northern borehole (BH18-1) and monitoring wells (MW-306) beginning on July 16, 2018. Initial activities will include outer casing advancement, overburden well construction based on field observations of drilled soils during BH18-1 casing advancement, and drilling of 150-feet of bedrock. Geophysical logging activities will occur during the next step to identify water-bearing zones for packer sample collection thereafter. Packer sampling results will be used to recommend monitoring zones for construction using

L&RR Superfund Site (229620.01) 3 Woodard & Curran QSR-09 Quarterly Summary Report July 13, 2018

Solinst’s CMT multi-level system. Baseline groundwater samples are anticipated to be collected at the end of September.

• Collection of samples associated with the 2018 Pre-ROD Event and the second round of additional PFAS sampling at the end of July. Validated PFAS data will be incorporated into an interim submittal in August 2018 prior to the third round of PFAS sampling.

• Continuation of 1,4-dioxane treatability studies and receipt of test updates from Sentinel.

If you have any questions or would like to further discuss these results, please do not hesitate to contact me.

Sincerely,

WOODARD & CURRAN INC.

Alan Benevides, P.E., L.S.P. Senior Project Manager AAB/ams

Attachment: Figure 1: Updated Site Plan

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