revised interim final - semspub.epa.gov

COMMITMENT & INTEGRITY

DRIVE RESULTS

33 Broad Street | One Weybosset Hill

Floor 7

Providence, Rhode Island 02903

www.woodardcurran.com

T 800.985.7897

T 401.273.1007

F 401.273.5087

Via Electronic Mail

June 7, 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: L&RR Superfund Site – OU 2 RI/FS 2018 Pre-ROD Sampling – Revised Work Plan

Dear Ms. Krasko and Mr. Kulpa:

In accordance with the Interim Final Remedial Investigation/Feasibility Study (RI/FS) Work Plan (dated May 23, 2016), this transmittal presents the revised Work Plan for the 2018 round of Pre-Record of Decision (ROD) Sampling at the L&RR Superfund Site in North Smithfield, Rhode Island (the Site). This Work Plan has been revised from the initial version, dated March 13, 2018, to incorporate comments received from the U.S. Environmental Protection Agency (USEPA) on April 4, 2018 and discussed in detail during a conference with USEPA and their oversight contractor, AECOM, on April 10, 2018. Responses to comments received on April 4, 2018 along with additional comments received electronically on April 23, 2018 are provided in Attachment A.

It should be noted that comments received to date have focused on providing additional information to support amending the 2018 sampling scope from previous Pre-ROD activities in 2017. This revised submittal also clarifies analytical methods with respect to attainment of Project Action Limits (PALs) to the extent practical based on analytical reporting limits specified by the contracted laboratory.

The second round of Pre-ROD Sampling will be conducted in accordance with the requirements of Appendix D to the Administrative Settlement Agreement and Order on Consent (AOC) for RI/FS with an effective date of August 17, 2015. Following USEPA and the Rhode Island Department of Environmental Management (RIDEM) review, we propose to perform sampling two weeks following Work Plan approval.

Sampling Media, Locations and Parameters

During the initial round of Pre-ROD Sampling, 46 groundwater samples were collected from 11 monitoring wells and 11 Solinst® Continuous Monitoring Technology systems (CMTs) with sampling “channels” across multiple aquifer units in March and April 2017. The 2018 event is consistent with the previous round and proposes collection of 43 groundwater samples from eight monitoring wells and 11 CMTs. For surface water, samples were initially collected at 31 locations during the June/July 2016 round and from 29 sample locations during the May 2017 event. The 2018 event also proposes collection of surface water samples from a subset of 13 locations. Table 1, attached, provides a summary of the proposed locations for groundwater and surface water sampling and the sampling techniques and analyses to be performed at each. Refer to Figure 1 for an overview of locations proposed for sampling. In general, sampling procedures and analytical methods during this round of Pre-ROD Sampling will be conducted in

L&RR Superfund Site (229620.01) 2 Woodard & Curran 2018.06.07 Pre-ROD Sampling WP June 7, 2018

accordance with the January 2017 Recommendations for Pre-ROD Groundwater Sampling and associated Comment Responses submitted on March 3, 2017 with the following revisions:

• Proposed Analyses: Based on results of the March/April 2017 Pre-ROD Groundwater Sampling activities, it is proposed that 43 groundwater samples from eight monitoring wells and 11 CMTs be submitted for laboratory analysis of volatile organic compounds (VOCs) via method 8260C1, 1,4-dioxane via method 8270D Selective Ion Monitoring (SIM), and total and dissolved priority pollutants (PP13) metals via method 6020A/7470A only. Samples will also be collected for semi volatile organic compound (SVOC) analysis using method 8270D-SIM “very low” reporting limits provided by Alpha Analytical’s Mansfield, Massachusetts laboratory from a subset of 10 monitoring locations. Samples will not be submitted for analysis of polychlorinated biphenyls (PCBs) and pesticides based on non-detect concentrations for these compounds reported during the March/April 2017 sampling event. Correspondence received from USEPA on April 23, 2018 confirmed the 2018 event could proceed without these analyses; refer to additional detail in Attachment A.

• In situ Biodegradation/Attenuation Sampling: Consistent with the March/April 2017 Pre-ROD Groundwater Sampling event, a subset of 10 samples will be submitted for analyses to support the evaluation of in situ biodegradation/monitored natural attenuation at the Site including ammonia via method EPA 350.1, chloride via EPA method 300.0, methane/ethane/ethane via AM20GAX, nitrate via EPA method 9056, sulfate, nitrogen, and phosphorous via method 4500, total organic carbon via modified method 9060, alkalinity via method 2340B, and total dissolved solids (TDS) via EPA method 2540. Hydrogen was analyzed during the March/April 2017 Sampling and has been eliminated during this event based on the presence of 1,4-dioxane in groundwater and the lack of VOCs susceptible to reductive dechlorination. Refer to the comment response in Attachment A for additional information.

• Surface Water: 13 surface water locations were selected based on the zones of groundwater discharge east of the landfill (TB-5 through TB-10), Tributary area locations south of the landfill (TRIB-3 through TRIB-5), and samples in Trout Brook Pond to the north of the Site (TB-12 through TB-15). Surface water samples will be collected using a peristaltic pump or a transfer vessel in accordance with SOP-9 Standard Operating Procedure for Surface Water Sampling of the QAPP and submitted for laboratory analysis of VOCs via method 8260C, 1,4-dioxane via method 8270D SIM, and total and dissolved PP13 metals via method 6020A/7470A.

Sampling and Analysis Procedures

Samples will be submitted on ice to Alpha Analytical Laboratory’s Mansfield and Westborough, Massachusetts facilities for analysis under proper chain of custody protocols. To evaluate data reliability as it pertains to sample representativeness, quality control (QC) samples will be collected in accordance with the January 2017 Recommendations for Pre-ROD Groundwater Sampling. Upon receipt of the analytical data from the laboratory, the data will receive a Modified Tier 1 Plus evaluation, with the exception of low-level 1,4-dioxane analyses which will receive a Tier 2 evaluation in general accordance with the Quality Assurance Project Plan (QAPP) and the Region I, EPA-NE Environmental Data Review

1 The 8260C VOC analysis also includes more sensitive reporting limits for benzene, carbon tetrachloride, trichloroethene, and vinyl chloride for conformance with PALs listed in the project QAPP.

L&RR Superfund Site (229620.01) 3 Woodard & Curran 2018.06.07 Pre-ROD Sampling WP June 7, 2018

Supplement for Regional Data Review Elements and Superfund Specific Guidance/Procedures (United States EPA, 2013). Qualifications will be applied to the data as necessary based on this evaluation.

Schedule

Pending USEPA concurrence on these sampling recommendations, Woodard & Curran requests to conduct sampling activities two weeks following approval of the revised Work Plan. We anticipate sampling to occur in mid- to late June 2018 which remains consistent with RIDEM’s request for sampling to occur during the summer months.

During the December 19, 2017 meeting, USEPA requested that two rounds of groundwater samples be collected from the MW-305 overburden CMT system located on Lot 24 along Pound Hill Road. This location was previously sampled on March 8, 2017 and indicated results of 1,4-dioxane above PALs from two CMT monitoring zones (MW-305B; with result of 71.8 micrograms per liter [µg/L] and MW-305C at 6.89 µg/L). Based on this result, each of the three CMT zones were re-sampled on May 25, 2017 and the concentration of 1,4-dioxane at these CMT intervals were below laboratory reporting. To evaluate nature and extent objectives at MW-305, the initial Work Plan proposed that a second round of samples be collected when conditions in Trout Brook and the associated wetlands are seasonably drier to replicate similar conditions for which samples were collected in 2017. Now that sampling is proposed to occur in mid- to late June, a second set of samples is no longer proposed since conditions in June are anticipated to remain consistent with the collection of samples on May 25, 2017.

We will also evaluate seasonal precipitation levels and rely on a network of pressure transducers installed at select piezometer locations for comparison with seasonal conditions during the previous sampling event in 2017.

If you have any questions, please do not hesitate to contact me.

Sincerely,

WOODARD & CURRAN INC.

Alan Benevides, P.E., L.S.P. Senior Project Manager AAB/ams Enclosures: Table 1: 2018 Pre-ROD Sampling Analytical Testing Summary – Revised Figure 1: 2018 Pre-ROD Sampling Plan – Revised Attachment A: Recommendations for 2018 Pre-ROD Sampling – Comment Response

cc: L&RR PRP Group

PN: 0229620.01

L&RR Superfund Site (229620.01) Woodard & Curran 2018.06.07 Pre-ROD Sampling WP June 7, 2018

TABLE

Table 1

2018 Pre-ROD Sampling Analytical Testing Summary - Revised

L&RR Superfund Site OU 2 RI/FS

North Smithfield, RI

Pre-ROD Expanded Sampling

1,4-Dioxane

8270 SIM

VOCs

8260C

Total PP13

Metals

6020A/7470A

Dissolved (3)

PP13 Metals

6020A/7470A

SVOCs

8270D SIM

Ammonia

350.1

Chloride

300.0

MEE

AM20GAX

Nitrate

9056

Sulfate

4500

TOC

9060

Alkalinity

2340B

Nitrogen

4500

Phos-

phorous

4500

TDS

2540

New Monitoring Locations (Installed 2016)

131 - 136 BH16-1 (131-136) X X X

171 - 175 BH16-1 (171-175) X X X

182.5 - 191 BH16-1 (182.5-191) X X X

155 - 165 BH16-2 (155-165) X X X

190 - 196 BH16-2 (190-196) X X X X X X X X X X X X X X

235 - 245 BH16-2 (235-245) X X X

88 - 98 BH16-3 (88-98) X X X

107 - 115 BH16-3 (107-115) X X X

138 - 150 BH16-3 (138-150) X X X X X X X X X X X X X X

127 - 133 BH16-4 (127-133) X X X

191 - 201 BH16-4 (191-201) X X X

209 - 219 BH16-4 (209-219) X X X

110 BH16-5 (110) X X X

138.5 BH16-5 (138.5) X X X

172.5 BH16-5 (172.5) X X X

Overburden - Kame 11.4 - 19.4 MW-301D X X X X

Overburden - Kame 45.9 - 50.9 MW-301C X X X X

Overburden - Ice

Contact80.8 - 86.8 MW-301B X X X X

Overburden - Ice

Contact98.0 - 98.6

(4) MW-301A X X X X


Overburden - Kame 29.3 - 39.3 MW-302B X X X X X X X X X X X X X X X

Overburden - Ice

Contact61.0 - 71.0 MW-302A X X X X

Overburden - Kame 20.6 - 30.6 MW-303D X X X X X X X X X X X X X X X


Overburden - Ice

Contact56.1 - 61.1 MW-303B X X X X X X X X X X X X X X X

Overburden - Till 76.8 - 77.3(4) MW-303A X X X X


Overburden - Ice


Overburden - Ice

Contact30.7 - 36.7 MW-304A X X X X


Overburden - Ice


Overburden - Ice

Contact30 - 36.7 MW-305A X X X X

Annual PCSM Locations

MW-102AOverburden - Ice

Contact62.7 - 73.3 MW-102A Bladder Pump X X X X X X X X X X X X X X X

MW-103A Fractured Bedrock 39.2 - 55.1 MW-103A Bladder Pump X X X X X

MW-104AOverburden - Ice

Contact Deposit43.5 - 54 MW-104A Bladder Pump X X X X X X X X X X X X X X X

CW-5BOverburden - Ice

Contact92 - 102 CW-5B Bladder Pump X X X X X


Contact27 - 37 CW-7B Bladder Pump X X X X X X X X X X X X X X X

Additional PCSM Locations

46 BH14-1 (46) X X X

73.5 BH14-1 (73.5) X X X

86 BH14-1 (86) X X X X X X X X X X X X X

CW-6A Fractured Bedrock 82 - 92 CW-6A Bladder Pump X X X X X X X X X X X X X X


Contact51 - 61 CW-6B Bladder Pump X X X X

CW-7A

Overburden/

Bedrock - Ice

Contact

37 - 47 CW-7A Bladder Pump X X X X

Discrete Interval

Sampler

(with Pump Operation)5

Discrete Interval

Sampler

(with Pump Operation )5

Peristaltic Pump

Peristaltic Pump

Peristaltic Pump

Peristaltic Pump

Peristaltic Pump

BH16-5

BH16-4 Bedrock

Bedrock

Open Borehole

BH14-1Bedrock

Open Borehole

MW-301

MW-302

MW-303

MW-304

MW-305

BH16-1 Bedrock

BH16-2 Bedrock

BH16-3 Bedrock

Location ID Sample ID

Hydrogeologic

Unit(1)

Screen

Interval/

Sample Depth

(ft bMP)(2)

Proposed Sampling

Method

Peristaltic Pump/ Micro-

pneumatic


pneumatic

In situ Biodegradation / MNA Specific AnalysesPre-ROD Sampling


pneumatic


pneumatic

L&RR Superfund Site (229620.01)

Table 1 - Revised 2018 Pre-ROD Sampling Analytical Testing Summary Page 1 of 2 Woodard & Curran

Table 1

2018 Pre-ROD Sampling Analytical Testing Summary - Revised

L&RR Superfund Site OU 2 RI/FS


Pre-ROD Expanded Sampling

1,4-Dioxane

8270 SIM

VOCs

8260C

Total PP13

Metals

6020A/7470A

Dissolved (3)

PP13 Metals

6020A/7470A

SVOCs

8270D SIM

Ammonia

350.1

Chloride

300.0

MEE

AM20GAX

Nitrate

9056

Sulfate

4500

TOC

9060

Alkalinity

2340B

Nitrogen

4500

Phos-

phorous

4500

TDS

2540Location ID Sample ID

Hydrogeologic

Unit(1)

Screen

Interval/

Sample Depth

(ft bMP)(2)

Proposed Sampling

Method

In situ Biodegradation / MNA Specific AnalysesPre-ROD Sampling

Surface Water Locations

TB-5 Surface Water NA TB-5Peristaltic Pump/

Transfer VesselX X X X



















TRIB-3 Surface Water NA TRIB-3Peristaltic Pump/






Notes:

(1) Hydrogeologic unit based on stratigraphic details provided in OU 1 related documents and updated based on field interpretations during OU 2 RI activities.

(2) ft bMP - Feet below Measuring Point and correspond with the following MPs: Bedrock Boreholes = Top of Casing; Overburden Multi-Level Systems = Top of CMT Tubing; Monitoring Wells = Top of PVC riser

(3) If turbidity measurements exceed 50 nephelometric turbidity units during purging of bedrock locations than a dissolved sample will also be submitted.

(4) Final CMT channel screened at the base of the borehole using a 6-inch zone. Sampling of this zone may be difficult due to depth, limited extent of screen, and low permeability of screened hydrogeological unit.

(5) Peristaltic or submersible pump to be used during purging 2-feet above discrete interval sampler to enhance flow from the formation where the sample is to be collected.

Abbreviations:

Analyses: PCSM = Post-closure monitoring program; VOCs = volatile organic compounds; BOD = biological oxygen demand; COD = chemical oxygen demand; MEE = methane/ethane/ethene; TOC = total organic carbon; TDS = total dissolved solids

L&RR Superfund Site (229620.01)

Table 1 - Revised 2018 Pre-ROD Sampling Analytical Testing Summary Page 2 of 2 Woodard & Curran


FIGURE

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L ot #66

L ot #23

L ot #24

L ot #70

L ot #173

L ot #51

L ot #106

L ot #90L ot #9A

L ot #68

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L ot #15

CW-6C

CW-7C

CW-5CCW-5ABH18-1

MW-201

MW-202

MW-101

DW-1431 DW-1375

DW-1363

DW-1325

MW-102B

MW-104B

MW-103B

DW-1317-1321

DW-1309-1313

DW-1301-1305

CW-5B

CW-7A

CW-6BCW-6A

CW-7B

MW-305

MW-304

MW-301

MW-302

MW-303

BH16-4

BH16-5

BH16-3

BH16-2

BH16-1

BH14-1

MW-104A

MW-103A

MW-102A

TB-13

TB-14

UG-2

UG-1

UG-6

UG-5UG-4 UG-3

TRIB-9

TRIB-8

TRIB-7

TRIB-1

TRIB-10

TRIB-4

TRIB-5

TRIB-3

TB-1

TB-3TB-4

TB-11

TB-5TB-6

TB-7

TB-8TB-9

TB-10

TB-12

TB-15

TRIB-6

Figure 1

L&RR Superfund SiteOU 2 Remedial Investigation

/Feasibility Study

Proje c t #: 229620Map Cre ate d : June 2018

0 200 400100Fe e t

LegendHydrogeological Locations

&=Be d rock Multi-L e ve lSyste m

! Be d rock Bore hole

@A Monitoring We ll

&%Ove rb urd e n Multi-L e ve lSyste m

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2018 Pre-ROD Sampling PlanREVISED

Third Party GIS Disc laim e r: This m ap is for re fe re nc e and grap hical p urp ose s only and should not b e re lie d up on b y third p artie s for any le gal d e c isions. Any re lianc e up on the map or d ata containe d he re in shall b e at the use rs’ sole risk. Data Sources: USGS, City of North Smithfield, RI

Note s1. Parc e l b ound arie s inte rp re tte d fromMay 2012 Existing Site Plan (Drawing C-01) and the Town of North Sm ithfie ld(Nove m b e r 2013) and m ay not re fle c ton-the -ground ac curacy.2. Data d isp laye d in NAD83 RI StatePlane and NAV D883. Orthop hotograp hy from U SGS, Ap ril2014.4. Exte nt of we tland fe ature s surve ye d inJuly 2016 b y DiPre te Engine e ring.We tland s e ast of Pound Hill Road andne ar the Slate rsville Re se rvoirs areb ase d up on the National We tland sInve ntory.5. We tland sam p le s will b e c olle c te dfrom locations c onsiste nt with May 2017sam p ling e ve nt. L ocations are b ase d onfie ld m ark-outs at the tim e of sam p lingand /or up on GPS d ata colle c te d d uringsam p le location p re -m arkout ac tivitie s onJune 22, 2016.

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1 inc h = 400 fe e t

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TB-17

TB-16

Trout Brook Pond

INSET: Northern Extent of Trout Brook Pond (TB-16 and TB-17)

L ocation Prop ose d for Sam p ling


ATTACHMENT A: RECOMMENDATIONS FOR 2018 PRE-ROD SAMPLING – COMMENT RESPONSE

COMMITMENT & INTEGRITY

DRIVE RESULTS

33 Broad Street | One Weybosset Hill

Floor 7

Providence, Rhode Island 02903

www.woodardcurran.com

T 800.985.7897

T 401.273.1007

F 401.273.5087

Via Electronic Mail

June 7, 2018

Ms. Anna Krasko U.S. Environmental Protection Agency 5 Post Office Square, Suite 100 Mail Code OSRR07-1 Boston, MA 02109-3912 Re: Recommendations for 2018 Pre-ROD Sampling – Comment Responses Administrative Settlement Agreement and Order on Consent (OU 2) L&RR Superfund Site, North Smithfield, RI

Dear Ms. Krasko:

Woodard & Curran has reviewed comments from the U.S. Environmental Protection Agency (USEPA) dated April 4, 2018 regarding Recommendations for the 2018 Pre-ROD Groundwater Event dated March 13, 2018, for Operable Unit (OU 2) of the Landfill & Resource Recovery Superfund Site (the “Site”) in North Smithfield, Rhode Island. This response to comment letter, submitted at the request of the Respondents, addresses each response to those comments from USEPA and Rhode Island Department of Environmental Management (RIDEM). In addition to comments received on April 4, 2018, USEPA, and their contractor, AECOM, and Woodard & Curran participated in a conference call on April 10, 2018 to discuss these comments in more detail. This discussion was followed by email correspondence from USEPA on April 23, 2018 which summarized the outcome of the conference call and provided additional clarification on select comments, specifically those relating to laboratory reporting limits as specified in the October 2016 Interim Final Quality Assurance Project Plan (QAPP).

Each of the comments is re-printed below in italicized format followed by our response.

USEPA Comments

Comment #1. Sampling Media, Locations, and Parameters, 1st bullet (Proposed Analyses), p. 1.

The decision to eliminate sampling for SVOCs, PCBs and pesticides is based on the data from the March/April 2017 sampling event. The reporting limits for many of the SVOCs in that data set (presented in Attachment A to the subject letter) are greater than the PQLs presented in Table 6-14 of the QAPP (October 11, 2016), and several are also above the PALs. In Section 4.4.4.3 of the RIFSWP (May 23, 2016), it is stated that SVOC analyses for groundwater samples will be performed at Alpha Analytical Laboratory, Mansfield, MA to achieve reporting limits consistent with the PALs in the QAPP. A footnote to Table 6-14 in the QAPP indicates that the Mansfield, MA Alpha Laboratory is where the “very low” reporting limits are to be achieved. Although the transmittal letter for the October 2016 re-submittal of the QAPP indicates that the reporting limits for PAHs in the “very low” column apply to only pore water (and surface water and sediment) samples, presumably the remaining PQLs in Table 6-14 do apply to groundwater. The QAPP and associated documents seem to suggest that, at a minimum, the PQLs for SVOCs in groundwater should be consistent with those in the very low (not including SIM) analysis (0.5 ug/L). Please provide a discussion regarding whether or not at least one set of groundwater samples should use the “very low” reporting limits to achieve the PALs.

L&RR Superfund Site (229620.01) 2 Woodard & Curran 2018.06.07 2018 Pre-ROD Comment Response June 7, 2018

Response:

As discussed during the April 10, 2018 conference call with USEPA and AECOM, groundwater samples during the 2018 Pre-ROD event will be analyzed for semi volatile organic compounds (SVOCs) using “very low” reporting limits at Alpha’s Mansfield, Massachusetts laboratory. Samples for pesticides and polychlorinated biphenyls (PCBs) will not be collected during this event based on the lack of detections during the first sampling event, which were subsequently reviewed by AECOM and documented in correspondence received from USEPA on April 23, 2018.

Comment #2. Sampling Media, Locations, and Parameters, 2nd bullet (In Situ Biodegradation/Attenuation Sampling), p. 2.

It is proposed that hydrogen be eliminated from the 2018 sampling event based on “analytical results and groundwater geochemistry.” Please provide a brief statement regarding what was determined in the first round, and why additional hydrogen data would not be useful to the project objectives.

Response:

Dissolved hydrogen analysis is typically used to assess in situ hydrogen produced during fermentation of volatile organic compounds (VOCs). Hydrogen concentration is proportional to the strength of biologically-mediated redox reactions for anaerobic groundwater. Review of groundwater results for the Site, generally indicates low to non-detect levels of VOCs associated with the subset of chlorinated ethene compounds that are ultimately degradable by reductive pathways under anaerobic conditions. Preliminary interpretations of the results indicate proportionally elevated concentrations of 1,4-dioxane in groundwater, which preferentially degrades under aerobic conditions by co-metabolic pathways. Due to the presence of 1,4-dioxane and the lack of VOCs susceptible to reductive dechlorination, hydrogen analysis has been omitted from the 2018 sampling event.

Comment #3. Sampling Media, Locations, and Parameters, 3rd bullet (Surface Water), p. 2.

The proposed surface water analyses do not include SVOCs, PCBs, pesticides, or anions but there is not an explanation given as to why those should be dropped from the program. Please provide a brief statement regarding why additional data for these analytes is not needed for this third round of surface water sampling.

Response:

SVOCs, PCBs, and pesticides were not included in the 2018 program based on the two rounds of surface water data incorporated into the Screening-Level Ecological Risk Assessment (SLERA) and Refinement. Data for these compounds in surface water from the June/July 2016 event, identified the pesticide, dichloro-diphenyl-trichloro-ethane (DDT), as the only constituent with the potential to pose an ecological risk. The second round of wetland and ecological sampling conducted in May 2017 only included collection of pesticide samples for DDT analysis, and no further SVOC and PCB samples. DDT results for the May 2017 event were not detected above minimum laboratory reporting limits. Collectively, these results were used to support the conclusion from the SLERA and Refinement that no contaminants of potential ecological concern (COPECs) were identified for surface water.

Surface water samples will be collected for analysis of VOCs, 1,4-dioxane, and metals to understand groundwater-surface water interaction conditions.


RIDEM Comments

Comment #1. Sampling Media, Locations and Parameters

The Work Plan proposed eliminating certain classes of contaminants of concern based upon observed concentrations. It seems that some of the detection limits may have been above standards? If this is the case please retain these classes of contaminants and employ lower detection limits in the analysis.

Response:

This comment was discussed in detail during the April 10, 2018 conference call and summarized in USEPA’s April 23, 2018 email. Refer to the response for USEPA Comment #1 above and the incorporation of the April 23, 2018 correspondence below.


The Work Plan proposes reducing the number of monitoring wells undergoing analysis from eleven to eight based upon the results of the spring 2017 sampling round. Typically, more than one round of samples is collected from a monitoring well to evaluate potential seasonal affects and/or effect of high or low water tables. At this site, the data presented demonstrates seasonal effects. Therefore, please retain all wells for the analysis.

Response:

In 2017, 46 groundwater samples were collected, while the 2018 event proposes to collect 43 samples. The network of overburden and bedrock Continuous Monitoring Technology systems (CMTs) remains consistent between the two events, however the primary difference involves removal of three monitoring wells (MW-201, MW-202, and MW-104B) associated with OU 1 post-closure monitoring. Two of these wells (MW-201 and MW-202) were recently sampled during OU 1 activities on May 1, 2018. A review of the 2017 results from MW-104B indicated there were no detections of VOCs or 1,4-dioxane. This well was omitted from the 2018 event due to the lack of detections and the fact that the couplet at this location, MW-104A, has been routinely sampled to evaluate groundwater quality in this portion of the landfill.

We remain cognizant of groundwater seasonality effects regarding interpretations of dissolved-phase constituents. Based on the data seasonality evaluation bar graphs included with the March 13, 2018 Work Plan, there does not seem to be a clear seasonal effect. For instance, overburden VOC results for the WL-2 (July 2013) and MW-302 (March 2017) were consistent for the three CMT zones sampled in March 2017, while the WL-2 results for the 32.7 feet below ground surface (ft bgs) interval were higher than the other two WaterlooAPS zones sampled. Similarly, the VOC results for well WL-4 (July 2013) and MW-303 (March 2018) location were generally consistent between both sampling rounds. Samples from bedrock boreholes were similarly mixed where concentrations of VOCs (including 1,4-dioxane) were detected at the BH16-2 and BH16-3 boreholes. At BH16-2, VOC results for the lower two CMT zones sampled in May 2017 were higher than the uppermost zone sampled during borehole advancement in September 2016. A similarly less evident trend occurred at BH16-3 for VOCs collected via packer methods in September 2016 compared with CMT sampling in March 2018. Possible explanations for these trends may be related to higher groundwater velocities in coarse-grained overburden materials and less transient conditions in the bedrock aquifer.



The Work Plan proposes to reduce the number of surface water samples from approximately thirty to thirteen. The Work Plan notes that sampling will focus on seeps, however it has not provided analytical justification for this reduction. Please either resample all of the previous locations or provide data to support a reduction.

Response:

As noted in Comment #2 above, surface water samples were collected at 31 locations in June/July 2016 and 28 locations in May 2017. These results were comprehensively used to evaluate ecological risks, and no specific risk drivers were indicated for surface water. The intent of surface water sample collection during the 2018 event, is to evaluate groundwater-surface water relationships by collecting surface water samples at a select subset of locations hydraulically downgradient of the landfill in the Tributary and Trout Brook sample areas. Surface water samples are also proposed for collection further downgradient in Trout Brook Pond.


The Work Plan proposes eliminating SVOCs, PCBs pesticides and certain metals from the surface water analysis. Please either include all of the analytes of concern in the analysis or provide justification, including analytical data, in support of the proposed reduction.

Response:

As previously noted in the response to USEPA Comment #3, surface water samples will be collected for analysis of VOCs, 1,4-dioxane, and metals to understand groundwater-surface water interaction conditions. Sampling for this reduced subset was reviewed and discussed during the April 10, 2018 conference call and subsequently agreed-upon in the April 23, 2018 follow-up correspondence (see below).


The Work Plan does propose the sampling of surface water; however, it does not propose sampling of sediments. Please provide a justification for the exclusion of this media, along with the appropriate analytical data.

Response:

Sediment results were previously collected during two rounds of wetland and ecological sampling in June/July 2016 and May 2017 to support the SLERA and Refinement. For sediment, the risk characterization identified arsenic and selenium as COPECs. For arsenic, concentrations in shallow and deep sediment were similar between the two sampling rounds, with the exception of the maximum detects being higher during the May 2017 event. Selenium results from the May 2017 were regarded as a data anomaly but retained as a COPEC based on the distribution of benchmark exceedances. Based on the density of samples collected from each study area (Tributary, Trout Brook, and Upgradient) to support the SLERA and Refinement, the range of variability under seasonally diverse wetland conditions is generally understood and no further sediment sampling is proposed.


Comment #6. Schedule

The Work Plan proposed collecting samples in April. This Office has expressed concerns associated with potential seasonal affects at the site. The Work Plan notes that there is seasonal variability at the site, and based upon the data submitted this Office concurs that there is seasonal variability, and in some cases the variability is quite significant. The Work Plan proposes collecting samples in April. A review of the submitted data indicates that in general, for the majority of contaminates, and in the majority of wells, higher concentrations were observed during the summer months. It is therefore recommended that the next round of samples be collected in the summer.

Response:

At this point, pending USEPA and RIDEM review, sampling is proposed to occur in early summer, preferably in June. Refer to the response to RIDEM Comment #2 regarding groundwater seasonality.

Comments Received from USEPA on April 23, 2018 (Electronic)

As a follow-up to EPA’s original comments on the recommendations for the 2018 Pre-ROD sampling, and the discussions that occurred during the recent conference call, we have the following conclusions/comments. Note that for the VOC and metals results in groundwater, and for the surface water and pore water results from the 2017 round, only the detected results were provided by W&C and reviewed.

Comment #1. Follow-up to USEPA Comment #1

The first comment on the “Recommendations for 2018 Pre-ROD Sampling” (W&C, 3/13/18) noted that the analyses of SVOCs in groundwater from the first sampling event did not produce the “very low” reporting limits (RLs) that were required by the QAPP. AECOM’s recollection from the conference call is that W&C agreed to collect samples for SVOCs during this round and to use the analytical method that achieves the very low RLs. You should confirm that in your response to comments, as well as provide a list of the wells from which the SVOC samples will be collected (e.g., all wells, or a subset). You should also confirm that for the VOC analyses, you will have the laboratory use the specific instrument that achieves an RL of 0.2 ppb for benzene, carbon tetrachloride, trichloroethene, and vinyl chloride. As a result of AECOM’s review of the pesticide and PCB results, we agree with the W&C proposal NOT to re-sample groundwater for those analytes.

Response:

Samples for SVOC analysis are proposed for collection at the same subset of locations as those proposed for the March 2017 Pre-Record of Decision (Pre-ROD) event, with the exception of MW-104B which is not proposed for sampling as part of the 2018 Pre-ROD event based on non-detect results in March 2017. This network remains consistent with what was proposed in the Remedial Investigation/Feasibility Study (RI/FS) Work Plan which included a subset of Post-Closure Site Monitoring (PCSM) locations, overburden CMT zones exhibiting elevated groundwater constituents, and bedrock CMT zones where constituents were detected from transmissive zones. Refer to the revised Analytical Testing Summary (Table 1 of the Pre-ROD Sampling Work Plan). Analysis of SVOCs will be performed at Alpha Analytical’s Mansfield, Massachusetts laboratory using method 8270D Selective Ion Monitoring (SIM) to achieve the “very low” reporting limits as specified in the QAPP.


In addition, VOC samples will be analyzed using more sensitive methods to achieve a reporting limiting (RL) of 0.2 micrograms per liter (µg/L) for benzene, carbon tetrachloride, tetrachloroethylene (PCE), trichloroethylene (TCE), and vinyl chloride in accordance with the QAPP.

Comment #2. Follow-up to USEPA Comment #2

Regarding the second comment, W&C should provide a brief rationale for not re-sampling for hydrogen analyses. We do not necessarily disagree with the proposed change, but W&C should submit a response that provides a bit more detail to support the rationale. Our recollection from the conference call is that W&C agreed to provide this information.

Response:

Yes, refer to the response to USEPA Comment #2.

Comment #3. Follow-up to USEPA Comment #3 (Surface Water)

Regarding the third comment, based on the completion of two rounds of surface water sampling, we agree with the W&C proposal to limit the analytes to VOCs, metals, and 1,4-dioxane for this third round. However, while reviewing the data from the first two rounds (note that only the tables of detected analytes were reviewed for the 2017 data), AECOM did note that in 2017, the RLs listed in the QAPP were not met for antimony, thallium, and nickel in pore water, nor for thallium and nickel in surface water. The RL for nickel was, in both cases, below the PAL. W&C should be certain that the reporting limits and the list of analytes meet the QAPP requirements for this third round of surface water sampling. Please confirm.

Response:

Woodard & Curran has reviewed the QAPP with respect to RLs and Project Action Limits (PALs) for the listed analytes and agrees that in some instances project quantitation limits (PQLs) outlined in the QAPP were not met. Attachment 1 provides a comparison of the RLs achieved by Alpha Analytical for metals analyses in groundwater and surface water compared to the PQLs and PALs established in the QAPP. Woodard & Curran will coordinate with Alpha Analytical to ensure these limits are achieved for surface water samples collected during the 2018 Pre-ROD event.

Comment #4. QAPP PALs and Analytical RLs (Groundwater Samples)

To the best of our knowledge, AECOM has only been provided with the results for detected VOCs and metals from the first round of groundwater sampling. Therefore, AECOM has not been able to compare the reporting limits achieved to those in the QAPP for all analytes in those 2 groups. Based on the results for detected metals, it appears that the QAPP RLs were not met for antimony, nickel, or silver, although in the latter two cases, the RL was below the PAL. There were no results for mercury and thallium, so the RLs could not be determined for comparison to the QAPP. For detected VOCs (representing less than half of the listed compounds), all QAPP RLs were met. W&C should be certain that the reporting limits and the list of analytes meet the QAPP requirements for this second round of groundwater sampling. Please confirm.

Response:

Consistent with the response to Comment #3 above, Woodard & Curran will coordinate with Alpha Analytical to ensure these limits are achieved for groundwater samples collected during


the 2018 Pre-ROD event. Refer to Attachment 1 for a comparison of PQLs and PALs provided in the QAPP.

Comment #5. Review of Manganese and Iron Aqueous Sampling

There were inconsistencies between the RIFSWP and the QAPP regarding whether or not manganese and iron would be analyzed in water samples from various media. It appears that they were not analyzed in any samples. Not surprisingly, the results from the OU1 sampling indicate that both of these metals are present in the groundwater. W&C should evaluate whether or not they should be analyzed in the groundwater and/or surface water samples from the upcoming event, and whether or not the risk assessments suffer any significant additional uncertainty. Please provide this evaluation.

Response:

Manganese and iron are analyzed in groundwater samples collected as part of the annual PCSM for OU 1 and were incorporated into the QAPP for completeness. Annual PCSM results indicate concentrations of iron and manganese above secondary maximum contaminant level (SMCLs) at select monitoring wells with consistent detections of VOCs and 1,4-dioxane and also at monitoring wells with MCL exceedances of arsenic (e.g. CW-7B, MW-102A, and MW-104A). Co-located dissolution of iron and manganese with VOCs and arsenic are attributed to oxygen depletion as mildly anaerobic conditions persist. As noted in USEPA Comment #2 above, concentrations of 1,4-dioxane remain proportionally elevated compared with VOCs and a key objective of RI/FS activities is to understand the potential for intrinsic biodegradation of 1,4-dioxane, which preferentially occurs under aerobic conditions. Levels of VOCs are significantly lower and contain fewer compounds amenable to reductive dechlorination under anaerobic conditions. While there is technical merit towards understanding the strength of reducing conditions supportive of chlorinated VOC reduction (and arsenic control), we contend that the suite of additional Monitored Natural Attenuation (MNA) parameters proposed for collection is sufficiently comprehensive to characterize prevailing aquifer geochemical conditions and no further iron and manganese samples are required beyond those collected annually at PCSM locations.

In addition, because the evaluation of surface water and porewater analytical results conducted for the SLERA did not identify issues with hardness dependent metals in these media it is unlikely that additional analytical results for iron and manganese would impact the outcome of the risk assessment. Therefore, we also contend there is minimal value in including these analyses in the 2018 Pre-ROD event.

Please let us know if you have any questions or need additional information.

WOODARD & CURRAN INC.

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


Attachment 1: Comparison of Analytical Reporting Limits to PQLs and PALs for Metals Analyses in Groundwater and Surface Water

cc: Warren Diesel, AECOM

Karen Douglas, Corning Incorporated Angela Knight, Corning Incorporated Curt Connors, Giarrusso Norton Cooley & McGlone, PC Roy Giarrusso, Giarrusso Norton Cooley & McGlone, PC

James Cashwell, Olin Corporation Paul Kulpa, RIDEM Judy Armour, Waste Management David Moreira, Waste Management

PN: 0229620.01

L&RR Superfund Site (229620.01) Woodard & Curran 2018.06.07 2018 Pre-ROD Comment Response May 7, 2018

ATTACHMENT 1: COMPARISON OF ANALYTICAL REPORTING LIMITS TO PQLS AND PALS FOR METALS ANALYSES IN GROUNDWATER AND SURFACE WATER

Attachment 1:

Comparison of Analytical Reporting Limits to PQLs and PALs for Metals Analyses

in Groundwater and Surface Water

L&RR OU 2 RI/FS


Sample Date March 2017 June 2016 May 2017

Analyte Reporting Limit Reporting Limit Reporting Limit

Metals

Antimony (Dissolved) ug/l 0.78 10 0.5 4 0.5 4

Antimony (Total) ug/l 0.78 10 0.5 4 2.5 4

Arsenic (Dissolved) ug/l 0.052 1.4 0.5 0.5 0.5 0.5

Arsenic (Total) ug/l 0.052 1.4 0.5 0.5 0.5 0.5

Beryllium (Dissolved) ug/l 2.5 0.17 0.5 0.5 0.5 0.3

Beryllium (Total) ug/l 2.5 0.17 0.5 0.5 0.5 0.3

Cadmium (Dissolved) ug/l 0.92 0.52 0.2 0.2 0.5 0.2

Cadmium (Total) ug/l 0.92 0.52 0.2 0.2 0.5 0.2

Chromium (Dissolved) ug/l 100 11 1 1 1 0.5

Chromium (Total) ug/l 100 11 1 1 1 0.5

Copper (Dissolved) ug/l 80 2.7 1 1 1 1

Copper (Total) ug/l 80 2.7 1 1 1 1

Lead (Dissolved) ug/l 15 0.54 1 1 1 0.5

Lead (Total) ug/l 15 0.54 1 1 1 0.5

Mercury (Dissolved) ug/l 0.063 0.15 0.2 0.2 0.2 0.1

Mercury (Total) ug/l 0.063 0.15 0.2 0.2 0.2 0.1

Nickel (Dissolved) ug/l 39 16.1 0.5 2 0.5 2

Nickel (Total) ug/l 39 16.1 0.5 2 0.5 2

Selenium (Dissolved) ug/l 10 5 5 5 5 5

Selenium (Total) ug/l 10 5 5 5 5 5

Silver (Dissolved) ug/l 9.4 0.32 0.25 0.4 0.25 0.4

Silver (Total) ug/l 9.4 0.32 0.25 0.4 1.25 0.4

Thallium (Dissolved) ug/l 0.02 0.47 0.2 0.5 0.2 0.5

Thallium (Total) ug/l 0.02 0.47 0.2 0.5 0.2 0.5

Zinc (Dissolved) ug/l 600 36.2 10 10 10 10

Zinc (Total) ug/l 600 36.2 10 10 10 10

Notes:

Blank spaces indicate samples were not analyzed for or a PAL or PQL was not established for the constituent.

Surface Water

Sample

Project Action Limits (PALs) and Project Quantitation Limit (PQL) established in the October 2016 Interim Final Sampling and Analysis Plan (SAP) including the Field

Sampling Plan (FSP) and Quality Assurance Project Plan (QAPP).

Sample Type

Units

Groundwater

Project Action

Limit

Surface Water

Project Action

Limit

Project

Quantitation

Limit

Groundwater

Sample

Surface Water

Sample

229620.01 (L&RR Superfund Site)

Attachment 1 - RL Comparison Page 1 of 1 Woodard & Curran

revised interim final - semspub.epa.gov

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