EHsS support

Davis Liquid Waste Superfund Site Smithfield, Rhode Island

Prepared for: Davis Site Performing Party Group

September 21, 2017

Prepared by: EHS Support, LLC Groundwater Geochemical and ESS Group, Inc.

Evaluation Technical Memorandum

consider done it MASSACHUSETTS RHODE ISLAND VIRGINIA 100 Fifth Avenue, 5th Floor 10 Hemingway Drive, 2nd Floor 999 Waterside Drive, Suite 2525 Waltham, Massachusetts 02451 East Providence, Rhode Island 02915 Norfolk, Virginia 23510 p +1 781.419.7696 p +1 401.434.5560 p +1 757.777.3777

September 21, 2017

Mr. Darryl Luce EPA New England Office of Site Remediation and Restoration 5 Post Office Square, Suite 100 Mail Code OSRR07-1 Boston, Massachusetts 02109-3912

Re: Groundwater Geochemical Evaluation Technical Memorandum Davis Liquid Waste Superfund Site Smithfield, Rhode Island ESS Project No. D164-007

Dear Darryl, On behalf of the Davis Site Group and pursuant to the RD/RA Consent Decree, Section X (Reporting Requirements), and Appendix B (Statement of Work) Section V.B (Pre-Design Investigation Plan), enclosed is the final Groundwater Geochemical Evaluation Technical Memorandum. This memorandum documents the evaluation of the additional analyte data (major and minor cations and anions and stable isotopes) from the Fall 2015 Site-wide Monitoring Event.

Electronic copies of the final document are also enclosed. Sincerely, ESS GROUP, INC. EHS SUPPORT CORP.

/ ,/ //-' / / / ;)'v\./ .re:. / / ,,-,/. L --

Jeffrey G. Hershberger, P.G. Nigel Goulding Project Manager Project Director

Enclosure (2 copies) C: Gary Jablonski (RIDEM) (1 copy) Liyang Chu (Nobis) (1 copy) Nigel Goulding (EHS) (electronic only) Joe Biss (EHS) (electronic only)

www.essg rou p,com environmental consulting & engineering services

TECHNICAL MEMO

To: Davis Site Performing Party Group

From: John Bartos, EHS Support LLC Jeff Hershberger, ESS Group, Inc.

CC: Joe Biss, EHS Support LLC

Date: September 21, 2017

Re: Groundwater Geochemical Evaluation Fall 2015 Groundwater Monitoring Event Davis Liquid Waste Superfund Site Smithfield, Rhode Island

ABSTRACT

EHS Support, LLC (EHS Support) and ESS Group, Inc. (ESS) have performed a groundwater geochemical evaluation using samples collected during the Fall 2015 Groundwater Sampling Event. The objective was to identify the different groundwater flow paths at the Davis Liquid Waste Superfund Site (the Site) through the use of groundwater geochemistry. The results of this evaluation support the following conclusions.

1. The evaluation has identified that there are three different geochemical types of groundwater at the Site:

a. Calcium-Bicarbonate – unimpacted, native groundwater (overburden and bedrock)

b. Calcium-Chloride – impacted by anthropogenic organic compounds

i. Elevated chloride concentrations are the result of historic and ongoing reductive dechlorination of chlorinated volatile organic compounds (CVOCs)

c. Sodium-Bicarbonate (and Calcium-Sodium-Bicarbonate) – minimally-impacted and unimpacted groundwater associated with the dike structure

2. The locations of wells exhibiting the unimpacted, native geochemical type (Calcium-Bicarbonate) groundwater is in agreement with the bedrock plume delineations as presented in the recently submitted Draft Conceptual Site Model submittal (Draft CSM).

a. This conclusion is also supported by the distribution of chloride at the Site, particularly within the bedrock.

3. The geochemical type groundwater within the dike structure (Sodium Bicarbonate and Calcium- Sodium-Bicarbonate) is different from the other Site groundwaters and is related to the different Davis Site Performing Party Group Groundwater Geochemical Evaluation September 21, 2017

mineralogy of the bedrock within the dike and suggests the potential for a longer residence time within the dike based on the limited areal extent of this feature.

a. The shift in the geochemical type for the groundwater in the dike structure relative to the other bedrock wells sampled is clearly evidenced on Figure 12 based on the analytical results for the three dike monitoring wells (OW-111-R, OW-80, OW-111-RD).

b. The geochemical type for the groundwater at dike well OW-111-RD is further shifted due to the higher concentration of chloride at this location. This appears related to the detections of Site contaminants in this well.

4. Surface waters display a different geochemical type (Calcium-Sulfate) and variability in isotopic signature likely due to variable evaporative losses (ponded vs. flowing) and variability in the influence of contributions from groundwater discharges, which typically have a heavier isotopic signature.

a. Sulfate may be coming from the wetland areas within and upstream of the Site as a result of sulfate reduction of sulfide compounds (e.g., hydrogen sulfide, iron sulfide) within the anaerobic sediments of the wetlands and also potential contribution from atmospheric deposition, as well

b. At the time of sampling, the stable isotope data suggest that there might be groundwater discharging into the surface water possibly at Latham Brook surface water station and within the Northern Wetlands.

5. Both the geochemical data and the stable isotope of hydrogen and oxygen data suggest mixing between lighter isotopic signature groundwater found in the unconsolidated deposits and heavier isotopic signature bedrock groundwater and that the degree of mixing varies across the Site.

a. Similarity between the native geochemical type for both the overburden and bedrock groundwaters supports mixing between the two units which is consistent with current Site conceptualizations and the location of the Site within a groundwater discharge area dominated by upward vertical gradients.

b. Stable isotope results suggest that the unconsolidated deposit groundwater and bedrock groundwater are both mixing between two different water sources within distinct isotopic signatures [recent groundwater derived principally from precipitation (approximately -7.3‰ δ18O) and deeper, regional groundwater influenced by recent Wisconsinan-aged glaciation (postulated to be between -10 and -14‰ δ18O) from scientific literature].

c. Overburden monitoring wells exhibiting the highest chloride concentrations (OW-43, OW-409-D), excluding well OW-200-O, are located in an area of suspected preferential upwelling from the underlying bedrock, likely related to key bedrock structural features.

6. The isotopic signature of the impacted groundwater varies spatially depending on the area of the Site and with respect to certain key geologic features, such as the East-West Fracture Trace.

The similarity in the ionic signature between the unimpacted groundwater within both the unconsolidated deposits and the bedrock is a strong indicator of mixing between the two units. This is supported by the prevalence of upward vertical hydraulic gradients within the bedrock and the location of the Site within a

2 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

discharge area where groundwater would be expected to be upwelling into the unconsolidated deposits and surface water.

The isotopic data also indicates a deeper, older groundwater probably representing the “regional” groundwater flow path that appears to be mixing with more recent groundwater of the local groundwater flow system. The isotopic data also supports that the degree of mixing is highly variable. This variability in mixing is likely due to variability in groundwater recharge derived from precipitation, complexity of the bedrock groundwater flow regime and associated variability in the flux of groundwater from the underlying bedrock into the unconsolidated deposits.

1.0 INTRODUCTION EHS Support, LLC (EHS Support) and ESS Group, Inc. (ESS) submit this technical memorandum on behalf of the Davis Site Performing Party Group (Davis Site Group) to summarize the findings of an geochemical evaluation of groundwater samples that were collected from both the unconsolidated deposits (overburden) and the bedrock during the 2015 Site-wide Groundwater Monitoring Program (Fall 2015) at the Davis Liquid Waste Superfund Site in Smithfield, Rhode Island (the Site). The regional location of the Site is provided on Figure 1 and a general Site Plan and the monitoring well network are shown on Figure 2.

1.1 Site Collected Data The Fall 2015 Site-wide Groundwater Monitoring Program consisted of the following analytes that were used in this evaluation:

• Analysis of samples from select monitoring wells (30 wells) for major and minor cations/anions and stable isotopes of oxygen and hydrogen.

• Analysis of samples from select surface water sampling locations (3 locations) for cations/anions and stable isotopes.

The sampling methodologies and analytical results of the analyses for target compounds are detailed in the Fall 2015 Site-wide Groundwater Sampling Report (ESS, 2016).

1.2 Background Data

A review of groundwater geochemical data available from the United States Geological Survey (USGS) and the State of Rhode Island Department of Environmental Management (RIDEM) was performed to develop background conditions for the Site area. Analytical data for nineteen groundwater monitoring wells and thirteen surface water sampling locations were available within ten miles of the Site using the National Water Information System (NWIS) database from the USGS. No geochemical data was found from RIDEM.

The majority of the background wells are under 60 feet in depth with three wells having a depth between 100 and 300 feet. Based on the limited available information from USGS NWIS database regarding the geological unit being screened for each of these wells, it is postulated that seventeen of these wells are completed in the unconsolidated deposits and two of the wells (RI-BUW 69 and RI-LIW 4) are completed in bedrock.

3 Davis Site Performing Party Group Groundw ater Geochemical Evaluation EHsS support September 21, 2017 consider it done

The surface water samples were taken from larger rivers or lakes. Eleven of the thirteen surface water samples are missing alkalinity results so further analysis other than average concentrations calculations is not possible. The analytical results from the NWIS database are tabulated in Table 1. 1.3 Objectives The objective of this assessment is to geochemically fingerprint groundwater within the unconsolidated deposits and fractured crystalline bedrock to assist in better defining the groundwater flow paths. As provided on Figure 3 from the Draft Final Conceptual Site Model (CSM) submittal (ESS/EHS, 2017), there are several possible groundwater flow paths within the bedrock. The concepts for the groundwater flow systems from the CSM submittal are from the classical paper from Toth (1963). As shown below using the concepts from Toth (1963), the majority of the groundwater flow is through local (shallow) groundwater flow paths with recharge and discharge within or very near the Site. At some unknown depth, there is a “deeper” groundwater flow path that represents the regional flow system. The hypothesis is that the groundwater found in the deeper fracture system will have a different geochemical signature and represents a much older and slow groundwater flowpath that is isolated from the “local” flow system. Refer to the example groundwater flow net diagram below which demonstrates shallow local flow systems and a deeper, regional flow system. Even if dissolved phase contamination is found in this “older” groundwater, the travel time for that impacted groundwater will be very long. The results of this evaluation can then be used to refine our understanding of the groundwater flow paths within the fractured bedrock.

t •---- tGi '' FRO UNDWATER ,..,AS INI , I

LOCAL R ECH_A_IRG'E ARE!: A

Groundwater samples were taken at clusters of monitoring wells completed at different depths to provide a “snapshot” of the potential difference in the geochemical signature between the unconsolidated deposits and the shallow, intermediate, and deep bedrock. These eight monitoring well clusters and individual bedrock Sentry Wells are representative of each of the different plume areas at the Site. The following table summarizes the wells sampled per each area. Three surface water samples were also collected to ascertain the geochemical signature of the surface water relative to the groundwater.

4 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

Unconsolidated Site Area Bedrock Wells Deposit Wells Former Source Area OW-51, OW-93-O OW-404-R, OW-101-R, OW-406-R Northern Plume Area OW-43, OW-112-O OW-41, OW-112-R, OW-407-R, OW-407-RD Down-Dip Plume OW-401-R, OW-401-RD, OW-411-RD Area Central Area OW-408-D, OW-409- OW-33, OW-410-R D Dike Area OW-111-O OW-111-R, OW-80, OW-111-RD Eastern Area OW-105-R, OW-105-RD Sentry Wells OW-86, OW-200-RD, SMW-2, SMW-3 Other Wells OW-200-O OW-200-R

The following figure shows these areas of the Site.

"- ~ 3) Down-Dip Plume --· ... - 11 - )-0 411-A:rea 4) Central Area Eastern Area .. : ---~,I n·~Jt--_e·--ry.·

2.0 SITE SETTING As detailed in the recently submitted Draft CSM, the unconsolidated lithology within the Study Area generally consists of sandy ground moraine deposits (Pleistocene-Wisconsin in age) and local swamp deposits (Holocene in age). The ground moraine deposits generally consist of an upper till layer of loose, medium to coarse sands and gravels, and a lower till layer of compacted clayey sands. The swamp deposits consist predominantly of organic peat and silt and range in thickness from approximately 1 to 10 feet. The swamp (wetland) deposits consistently overlay the glacial deposits (fine-grained silts, fine sands, and the sandy ground moraine deposits) within and proximal to the wetland areas. The lower, more compact, and less permeable glacial till deposits are rarely observed, and where observed, occur overlaying the bedrock surface.

An intrusive diabase dike (Triassic in age) occurs east and adjacent to the Site, trending north-south. The mapped location of the dike and its approximate projection north and south of the Site are shown on Figure 2. The dike material is characterized as a gray to dark gray, moderately hard diabase exhibiting

5 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

ophitic texture due to the laths of plagioclase feldspar. The mineralogy of the diabase includes pyroxene, olivine, and plagioclase feldspar with minor amounts of mafic minerals like magnetite, ilmenite, hornblende, and biotite. The dike structure is located in the general area of the Latham Brook basin outlet and has been previously characterized as a low-hydraulic conductivity feature, which has strong influences on groundwater flow conditions in both the overburden deposits and bedrock. Recent investigations indicate the dike limits the hydraulic connection between the gneissic bedrock on the west side of the dike (Western Fracture Network) and the schistic bedrock on the east side of the dike (Eastern Fracture Network).

Groundwater movement is distinctly different in the unconsolidated deposits and the underlying bedrock formations. The groundwater flow in the unconsolidated deposits is primary porosity advective flow through the grains of the sand and gravel deposits. The bedrock has very low primary porosity but does have secondary porosity in the form of fractures. The recently submitted Draft CSM has grouped the groundwater movement in the bedrock fractures by depth. The shallow/intermediate flow system is designated from 50 to 150 feet below ground surface (bgs) while the intermediate/deep flow system is designated from 150 to 400 feet bgs. Figure 3 is a concept drawing of the groundwater flow system dynamics from the Draft CSM for reference. Based on hydraulic heads in each of the zones, there is a strong and consistent upward vertical groundwater gradient in the bedrock into the unconsolidated deposits. The groundwater flow within the bedrock is also significantly influenced by other structural features, such as the East-West Fracture Trace and the diabase dike (Figure 4).

3.0 RESULTS The concentrations of the major and minor ions in the groundwater are a function of the water-bedrock interactions. The groundwater will interact with the bedrock and induces both dissolving of thermodynamically unstable minerals and the formation of new, thermodynamically stable minerals for that geochemical condition. The groundwater chemical composition will evolve with distance and time interacting with the bedrock. Differences in the evolution of various groundwaters will allow for “fingerprinting” or differentiating the types of water-bedrock interactions. Interactions with the presence of anthropogenic constituents like chlorinated ethenes and ethanes will also change the groundwater chemical composition. Biological processes involved in the degradation of these chlorinated constituents will also alter certain constituent concentrations, such as chloride, iron, alkalinity, hydrogen, and sulfate.

3.1 Charge-Balance Error To validate the quality of the aqueous geochemical data, the Charge-Balance Error (CBE) for each set of analytical results was assessed. The CBE is the relative difference of the total sum of all the posit ive charged ions (cations) to the negative charged ions (anions) in the water. Water is electrically neutral so the relative error should be zero. The following equation is the measure of the relative error with the analytes being reported in milliequivalents per liter (meq/L):

= I: cations - I I: anions! x 100 I: cations + I I: anions I

A positive CBE indicates that one or more of the cations was overdetermined, one or more of the anions was underdetermined, or both. Conversely, a negative CBE indicates that one or more of the cations was underdetermined, one or more of the anions was overdetermined, or both. Three possible causes for this error in the electrical imbalance are: lab errors (serious or systematic errors during analysis), some

6 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

dissolved species (major ions) are not measured, or using unfiltered samples that contain particulate matter which dissolved upon addition of acid for preservation purposes. Any CBE higher or lower than 20% is considered significant and the results are suspect for the subsequent evaluation. An example CBE calculation (bedrock well SMW-2) is shown below. The alkalinity, bicarbonate was reported by the laboratory with the units of mg/L as CaCO3. To support the calculation of mEq/L and evaluation of the CBEs, the alkalinity, bicarbonate was converted to mg/L as HCO3 by multiplying the laboratory concentration by 1.22.

Analyte Concentration Charge Molecular Concentration (mg/L) Weight (mEq/L) Cations Aluminum Non-Detect 3 27 0 Calcium 17 2 40.07 0.8485 Iron Non-Detect 2 55.85 0 Potassium 3.0 1 39.0983 0.0767 Magnesium 0.64 2 24.305 0.05266 Manganese 0.00099 2 54.938 3.604E-05 Sodium 6.2 1 22.989769 0.2697

Anions Alkalinity, 57.34 1 Bicarbonate 61.016 0.9398 (as HCO3) Chloride 3.0 1 35.453 0.0846 Sulfate 10 2 96.06 0.2082

SumCation 1.248 SumAnion 1.233 % Difference 0.6%

3.1.1 Background Groundwater Data CBE The NWIS dataset had seventeen of the nineteen samples with a CBE below 20%. The results of CBE calculations are tabulated on Table 1. The figure provided on Figure 5 is a histogram of the CBE results for the background samples. The mean of the calculated CBE is -5.4% for the dataset. CBE calculations were based on the available data for these wells. CBE calculations were not completed for the surface water samples due to the missing alkalinity data in the NWIS dataset. The two wells/samples exhibiting CBEs exceeding 20% are not included in subsequent data evaluations.

3.1.2 Site Data CBE The CBE of the analytical results 2015 Site-wide Groundwater Monitoring Program (Fall 2015) had 28 groundwater samples with CBE results below 20%. All of the bedrock monitoring wells and surface water sample results exhibited CBE results less than 20%. The average CBE result was -1.1% for all 30 of the groundwater samples. Table 2 has the CBE results tabulated for the Site data. As shown on Figure 6, two overburden groundwater samples (OW-93-O and OW-112-O) have CBE results of +21.3% and - 27.7%, respectively. These two samples had the lowest amount of solutes (total dissolved solutes) for any of the samples indicating that the error is likely due to these low concentrations. Based on evaluation of the data for individual wells and the entire dataset, the Davis technical team will eliminate the use of these two Site samples with CBE > 20% in subsequent data evaluations.

7 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

3.2 Background and Site Concentrations The NWIS dataset from the USGS was used to establish background concentrations for the major and some of the minor ions for typical Rhode Island groundwater. Figure 7 shows the summary statistics in histogram form for the NWIS background overburden groundwater analytical results. The summary statistics for the NWIS background overburden groundwater samples and the Site overburden wells are summarized below:

Table 3 – Summary Statistics for Overburden Wells (mg/L) NWIS Background Site Overburden Wells Overburden Wells Analytes

Minimum Mean Maximum Minimum Mean Maximum

Calcium 3.0 9.3 26.0 6.7 14.7 33.0

Iron 0.010 0.10 0.4 ND 3.7 7.2

Magnesium 0.3 1.7 4.8 1.1 3.2 4.9

Potassium 0.8 2.0 4.8 1.0 2.1 3.6

Sodium 2.3 11.7 26.0 4.4 8.7 17.0

Silica 4.8 9.3 13.7 8.5 15.4 21.0

Bicarbonate 4.0 19.9 60.0 4.6 41.9 98.0

Chloride 1.0 17.0 45.0 3.5 16.4 32.0

Sulfate 2.2 13.3 36.0 6.8 10.3 12.0

The analyte concentrations for the background sample from the one NWIS bedrock well with a calculated CBE less than 20% (RI-BUW 69) and the summary statistics for the Site bedrock wells are listed below:

8 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

Table 4 - Background Concentrations for NWIS Bedrock Well and Summary Statistics for Site Bedrock Wells (mg/L) NWIS Background Site Bedrock Wells Analytes Bedrock Well

Concentration Minimum Mean Maximum

Calcium 12 9.10 90.23 720

Iron 0.01 0.02 3.50 26

Magnesium 1.4 0.65 4.29 18

Potassium 1.2 0.39 4.90 34

Sodium 8 4.1 32.19 150

Silica 19 8.1 17.35 34

Bicarbonate 48 32 84.45 460

Chloride 7 2.2 179.34 1700

Sulfate 3.8 0.86 10.42 20

The summary statistics for the background surface water samples and the Site surface water samples are summarized below:

9 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

Table 5 – Summary Statistics for Surface Water Samples (mg/L) NWIS Background Site Surface Water Surface Water Analytes

Minimum Mean Maximum Minimum Mean Maximum

Calcium 2.9 5.0 7.9 9.4 17.47 29.00

Iron 0.3 0.7 1.3 0.2 1.66 3.70

Magnesium 0.5 1.0 1.6 1.8 2.37 3.30

Potassium 0.7 1.3 2.0 2.3 2.53 2.90

Sodium 1.8 8.3 23.0 4.7 6.10 7.50

Silica 1.0 3.7 8.8 4.6 12.20 18.00

Bicarbonate 6.0 7.3 9.0 2.4 9.47 16.00

Chloride 5.1 18.0 36.0 5.5 7.93 11.00

Sulfate 4.0 7.4 12.0 23.0 43.33 76.00

Discussion of the individual analytes relative to the background concentrations is presented in Section 3.7.

3.3 Trilinear Diagrams A trilinear (piper) diagram is a graphic representation of the chemistry of a water sample that has been used since the 1950’s. The cations and anions are shown by separate ternary plots. The apexes of the cation plot are calcium, magnesium and sodium plus potassium cations. The apexes of the anion plot are sulfate, chloride and carbonate plus bicarbonate anions. The two ternary plots are then projected onto a diamond. The diamond is a matrix transformation of a graph of the anions (sulfate + chloride/ total anions) and cations (sodium + potassium/total cations). The piper diagram is suitable for comparing the ionic composition (end members) of a set of water samples, but does not lend itself to spatial comparisons. Figure 8 is a generic trilinear diagram with the areas of the diagram designated relative to their different ionic compositions. The “regions” provided on the generic trilinear diagram on Figure 8 are the predominate types of naturally occurring groundwater geochemistry and were put on the figure for reference for the subsequent trilinear diagrams. The trilinear diagrams also can show mixing between two different types of groundwater with different ionic composition. This mixing will be depicted as a “straight” line on the projected diamond of the trilinear diagram.

A commercially available software from RockWare Incorporated called Aq-QA (Version 2015.1.14) was used for construction of the trilinear diagrams. The pH correction within the software was not used to

10 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

further speciate the alkalinity results since the laboratory analytical method already speciated the alkalinity between carbonate alkalinity and bicarbonate alkalinity.

In addition to the Stiff Diagrams, pie charts were developed using the analytical results from each of the groundwater locations to assist in the development of the geochemical type at each location. These pie charts are included in Attachment A.

3.3.1 Background Groundwater Trilinear Diagrams As provided on Figure 9, the USGS NWIS background unconsolidated deposits groundwater samples are generally grouped in one area of the trilinear diagram indicating a single ionic composition type of groundwater that is independent of depth. The background overburden groundwater type is primarily a mixture of the Calcium-Bicarbonate and Sodium-Chloride endmembers shown on Figure 8, with varying concentrations of chloride. This represents the background ionic composition signature for groundwater in the unconsolidated deposits based on the USGS NWIS data.

The one USGS NWIS background bedrock sample shown on Figure 9 appears to be a mixture of the Calcium-Bicarbonate and Sodium-Bicarbonate endmembers shown on Figure 8.

Surface water samples from the USGS NWIS database were not analyzed because the vast majority of the samples were missing alkalinity results that are needed for constructing the trilinear diagrams.

3.3.2 Site Trilinear Diagrams As provided on Figure 10, the surface water samples are grouped in a small area of the trilinear diagram indicating a single ionic composition type of water. This water is a Calcium-Sulfate type water. The Northern Wetland has slightly higher calcium and sulfate concentrations than the other two surface water locations.

The groundwater samples in the unconsolidated deposits exhibit a slightly different ionic composition to the USGS NWIS background groundwater samples. This water is a Calcium-Bicarbonate type as shown on Figure 11. The only exception was the groundwater sample from monitoring well OW-200-O which has a Sodium-Chloride ionic composition type. It is suspected that the elevated concentrations of both sodium and chloride at this location, relative to all of the other overburden well locations, may be the result of road salt applied to nearby Log Road. OW-409-D also plots slightly different from the other overburden wells due to a higher concentration of chloride that could be influenced by upwelling from the underlying bedrock, where chloride concentrations are higher.

The groundwater samples from the bedrock display three different ionic composition types or endmembers as shown on Figures 12 and 13. For reference on Figure 12, the blue symbols represent “shallow” bedrock groundwater samples while the green symbols represent “intermediate or deep” bedrock groundwater samples.

1. The first ionic composition type groundwater is a Calcium-Bicarbonate type and is associated with samples that have no to low concentrations of anthropogenic chlorinated organic compounds like chlorinated ethenes and ethanes. This type of groundwater represents the naturally occurring or native ionic composition within the bedrock and is similar to the unimpacted, native groundwater type in the overburden groundwater.

a. Includes: four Sentry Wells, OW-101-R, OW-105-R, OW-105-RD, OW-200-R, and OW-407-RD

11 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

2. The second ionic composition type is a mixture between the unimpacted, native Calcium-Bicarbonate type water and a Sodium-Bicarbonate type water. This water type is found at monitoring wells OW- 111-R, OW-80 and OW-111-RD which are screened in the diabase dike. The water sample collected from monitoring well OW-111-RD also exhibited an elevated chloride concentration (24 mg/L) likely due to the presence of low concentrations of COCs.

a. The shift in the geochemical type for the groundwater in the dike structure relative to the other bedrock wells sampled is clearly evidenced on Figure 12 based on the analytical results for the three dike monitoring wells (OW-111-R, OW-80, OW-111-RD).

b. As noted above, the geochemical type for the groundwater at dike well OW-111-RD is further shifted due to the higher concentration of chloride at this location resulting from the natural degradation of CVOCs which produces chloride.

3. The last type of groundwater has an ionic composition of Calcium-Chloride. This groundwater is an order of magnitude higher in concentrations of Calcium and Chloride than the unimpacted, native groundwater and this type of groundwater is associated with higher concentrations of anthropogenic chlorinated organic compounds.

a. Includes: OW-112-R and OW-407-R (Northern Plume Area) and OW-401-R, OW-401-RD and OW-411-RD (Down-dip Plume Area)

One of the powerful tools that trilinear diagrams provide is the ability to interpret possible mixing between two different geochemical types of groundwater. These mixing lines are straight lines on the diagram. The mixing line is usually not a linear relationship between the two different types of groundwater but will be dependent on the difference in ionic strength of the groundwater. An example of one of these mixing lines is between the native bedrock groundwater (calcium-bicarbonate) and the impacted bedrock groundwater (calcium-chloride). Examples of mixing between groundwater types are presented below.

• Groundwater samples from monitoring wells OW-33, OW-41, and OW-410-R appear to be mixtures of the native Calcium-Bicarbonate type groundwater and the Calcium-Chloride type groundwater resulting from their lower level of anthropogenic impacts which is expressed as lower chloride concentrations at these locations.

• The groundwater sample from OW-410-R also contains a slightly higher sodium concentration than the other wells in the Central Area of the Site likely due to its location within the thermally-altered zone proximal to the dike structure.

• The analytical results from OW-111-RD, located within the dike, provide another example of mixing. This sample has low levels of anthropogenic chlorinated organic compounds and appears to be a mixture between the Sodium-Bicarbonate type groundwater found in the diabase dike and the Calcium-Chloride type groundwater found within the impacted plume areas.

The groundwater samples from the Down-Dip Plume Area and the Northern Plume have higher chloride concentrations and can be distinguished on the trilinear diagram’s diamond from the groundwater sample from the FSA (OW-404-R). OW-404-R exhibits lower chloride concentration and higher sodium concentration than the wells located within the Calcium-Chloride type on Figure 12.

12 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

In summary, the evaluation of the trilinear diagrams has indicated that there are three unique groundwater ionic composition types at the Site. Each of these types of water has unique ratios of the major ions. The general location of these water types on the trilinear diagram is shown on Figure 13. The following table summarizes these water types. Additionally, the trilinear diagrams also provide visual evidence of mixing between the predominant groundwater types at the Site and the ability to visually assess differences between both individual wells and groups of wells.

Water Type Description

Calcium-Sulfate Surface Water

Calcium-Bicarbonate Unimpacted, Nat ive Overburden and Bedrock Groundwater

Sodium-Bicarbonate Dike Groundwater

Calcium-Chloride Impacted Bedrock Groundwater

3.4 Stiff Diagrams Like the trilinear diagrams, stiff diagrams, have also been in use since the 1950s, and were also constructed to provide a graphical representation of the chemistry of a water sample. A stiff diagram is a polygonal shape that is created from three parallel horizontal axes extending on either side of a vertical zero axis. Cations are plotted in meq/L on the left side of the zero axis, one to each axis, and the anions are plotted on the right side. An example of a stiff diagram is shown below for the sample taken from the Northern Wetlands. The upper horizontal line represents meq/L concentrations of magnesium and Sulfate. The middle line represents meq/L concentrations of calcium and alkalinity (carbonate and bicarbonate). The bottom line represents meq/L concentrations of sodium/potassium and chloride. For this surface water sample taken from the Northern Wetlands, the primary ions are calcium and sulfate.

.5 1.0 0.0 1.0 1.5

c, _ ------~

By standard convention, the points on each axis are connected to form the figure. By analyzing the shape of the figure, an evaluation can determine the ionic composition type of the groundwater sample. Stiff diagrams are more commonly used to evaluate spatial trends than trilinear diagrams. The stiff diagrams were constructed using a commercially available software from RockWare Incorporated called Aq-QA (Version 2015.1.14). The pH correction within the software was not used to further speciate the alkalinity results since the laboratory analytical method already speciated the alkalinity between carbonate alkalinity and bicarbonate alkalinity.

13 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

3.4.1 Site Surface Water Stiff Diagrams Stiff diagrams for the surface water samples are provided in Attachment B. Figure 14 shows the stiff diagrams for the surface water (yellow) on a simplified version of the conceptual geological structure map from the Draft CSM. The surface water samples illustrate the Calcium-Sulfate type water as discussed previously. The concentrations of individual cations and anions vary between the three locations likely due to variability in both evaporative losses and recharge from the underlying groundwater.

3.4.2 Site Unconsolidated Deposits Stiff Diagrams Stiff diagrams for the unconsolidated deposits water samples are provided in Attachment B. Figure 14 also shows the stiff diagrams for the unconsolidated deposits (orange). The unconsolidated deposits groundwater stiff diagrams show that the majority of these samples are predominantly Calcium- Bicarbonate type groundwater and have varying shapes as discussed below.

• Stiff diagrams for monitoring wells OW-51, OW-111-O and OW-408-D are similar.

• Stiff diagrams for monitoring wells OW-43 and OW-409D are similar and demonstrate the higher concentrations of bicarbonate and chloride at these locations. The higher concentrations of these analytes could be due to preferential upwelling from the underlying bedrock related to nearby structural features in the bedrock as shown on Figure 14.

• The stiff diagram for the groundwater sample from monitoring well OW-200-O has a distinctly different overall shape compared to the other unconsolidated deposit groundwater samples. The groundwater type for monitoring well OW-200-O is a Sodium-Chloride type water and this is the only groundwater sample exhibiting this water type. Based on the very low concentrations of the major ions in this sample, it appears to be somewhat anomalous. It is also possible that the geochemistry at this location may have been impacted by road salt used on nearby Log Road.

3.4.3 Site Bedrock Stiff Diagrams Stiff diagrams for the bedrock water samples are provided in Attachment B. The “shallow” bedrock stiff diagrams (blue) are also provided on Figure 15. The “intermediate and deep” bedrock stiff diagrams (green) are provided on Figure 16.

The native or background, unimpacted bedrock groundwater is a Calcium-Bicarbonate type water that has a “diamond-shaped” stiff diagram as shown below from monitoring well OW-200-R.

OW-200-R

0 00 10

14 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

The groundwater impacted with anthropogenic chlorinated organic compounds has a different shape that corresponds with the higher concentrations of both calcium and chloride detected in the samples from these wells. The typical stiff diagram is shown below from monitoring well OW-406-R. The groundwater samples from the FSA and Northern Plume Area have slightly higher alkalinity (bicarbonate) concentrations in relation to the chloride concentrations than groundwater samples from the Down-Dip Plume Area. The shapes of the stiff diagrams are similar between the Down-Dip Area and select Northern Plume monitoring wells (OW-406-R, OW-112-R and OW-407-R).

OW-406-R ,o ,o ,s

The other type of bedrock groundwater is present within the diabase dike (Sodium-Bicarbonate type water). The stiff diagram from monitoring well OW-111-R is shown below:

OW-111-R oa 00 o, 02 00 02 o• 00 oa

The different types of water evident from the trilinear diagrams are also apparent in the stiff diagrams. Overall, the native, unimpacted groundwater type not impacted by the anthropogenic constituents is readily apparent both spatially and vertically across the Site and supports the current plume delineations based on the distributions of COCs as further discussed in Section 3.7.

3.4.4 General Observations – Stiff Diagrams The following observations are provided based on review of the stiff diagrams for the surface water, unconsolidated deposits groundwater and bedrock groundwater samples as presented on Figures 14, 15 and 16.

• The locations of the wells exhibiting the unimpacted, native geochemical water type (Calcium- Bicarbonate) support the plume delineations within the bedrock as presented in the Draft CSM. This includes the following wells. Refer to Figures 15 and 16.

o OW-407-RD, OW-200-R (Northern Plume)

15 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

o OW-105-R, OW-105-RD (Eastern Area)

o OW-111-R, OW-80 (Dike Structure)

o OW-86, OW-200-RD, SMW-2, SMW-3 (Sentry Wells)

• The similarities between the geochemistry of the Down-Dip Area wells and the Northern Plume wells is consistent with similarities noted in the nature of the anthropogenic impacts at these wells and may indicate a similar source and interconnectivity between these areas, possibly related to the North- South Weathered Relict Bedding Feature noted in the Draft CSM.

• The different geochemistry within the dike structure (Sodium-Bicarbonate and Calcium-Sodium Bicarbonate) is likely related to the different mineralogy within the dike structure compared to the gneissic bedrock elsewhere on the Site. This geochemical difference also may suggest a longer groundwater residence time within the dike to facilitate these changes given the relatively limited areal extent of the dike structure.

• The native, unimpacted groundwater type (Calcium-Bicarbonate) is similar for both the overburden and bedrock groundwater. This similarity supports that interactions between the unconsolidated deposits and bedrock are ongoing in this area of the Site and is consistent with the location of the Site within a groundwater discharge area.

• Stiff diagrams for monitoring wells OW-43 and OW-409D are similar and demonstrate the higher concentrations of bicarbonate and chloride at these locations. The higher concentrations of these analytes could be due to preferential upwelling from the underlying bedrock related to nearby structural features in the bedrock.

3.5 Stable Isotope Results To identify differences in the geochemistry independent of the major ions, stable isotopes of oxygen and hydrogen were also analyzed at select monitoring wells and surface water locations during the Fall 2015 monitoring event. The stable (non-radioactive) isotopes of oxygen (18O) and hydrogen (deuterium; 3H) of the water molecule in groundwater are a reflection of the precipitation that recharged the groundwater. These stable isotopes reflect both the temperature but also the difference of precipitation events (e.g., snow storms versus a hurricane). The stable isotopes of the water molecule of the precipitation will vary widely over the year. The infiltration of the precipitation into the ground will attenuate the seasonal variations with depth. The stable isotopes measured in the groundwater will represent the “mean annual” isotopic value for the period of the recharge of the groundwater in that monitoring well.

The analytical results are reported as a ratio of 18O/16O and 3H/2H in comparison to a known standard. For these samples, the Vienna Standard Mean Ocean Water (VSMOW) was used as the standard and the ratio is reported in the units per mil (δ). No stable isotope data was available through the USGS NWIS database or any relatively close precipitation stations (Boston, MA) within the International Atomic Energy Agency’s Global Network of Isotopes in Precipitation (GNIP) database. The δ18O vs . δ3H results are provided on Figure 17 with the Global Meteoric Water Line (GMWL) for reference. The same figure is provided with interpretation from this dataset on Figure 18. Both of these figures also include the calculated Local Meteoric Water Line (LMWL) from all the groundwater samples. The root mean squared

16 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

(R2) value for the LMWL regression (δO=6.0δH - 1.67) for these samples is 0.96 indicating a good fit for the data set.

A regional data set was available from Dr. Anne Veeger of the Water Resources Center at the University of Rhode Island (URI) for surface water and groundwater samples taken from the Pawcatuck River Watershed located in southwestern Rhode Island and southeastern Connecticut. As shown on Figure 19, the URI dataset had a reported LMWL of δO=7.5* δH + 9.3 which has good agreement with the Site dataset. A summary of the URI dataset is provided in Attachment C.

The three surface water samples are enriched (positive) in both the lighter 16O and 2H isotopes in comparison to the groundwater samples. The surface water samples are enriched due to changes in the isotopic composition as a result of evaporation. The water molecules with the lighter oxygen (16O) and hydrogen (2H) isotopes will be preferentially lost due to evaporation before the heavier isotope molecules. This process is called evaporative enrichment of water. The samples from the Northern Wetlands and Latham Brook are not as enriched as the sample from the Eastern Ponded Wetlands. Either these samples did not undergo as much evaporation as the Eastern Ponded Wetlands or these samples are a mixture between the evaporated surface water reflected by the Eastern Ponded Wetlands and contributions from groundwater discharge into the surface water.

It is concluded that the background or native, unimpacted bedrock groundwater, that was identified by the trilinear and stiff diagrams, have similar isotopic signatures, samples contained within the brackets on Figure 17. The δ18O and δ3H values for the background groundwater are approximately -8.4‰ and -52‰, respectively. This clustering of the stable isotope data suggests that the background groundwater represents approximately the same mean isotopic recharge and is approximately the same groundwater age based on precipitation. Also, the groundwater samples that had the unique geochemical signature from the diabase dike are generally within the background isotopic signature indicating the same mean isotopic recharge. Thus the unique geochemical signature of these samples is likely the result of the difference in the geologic composition of the dike structure compared to the surrounding gneissic bedrock and potentially residence time in the dike structure.

Like the results from the trilinear diagrams, the stable isotopic composition of the groundwater with anthropogenic chlorinated organic compounds is different depending on the area. The groundwater from the FSA (OW-404-R) and the southern portion of the Northern Plume Area (OW-101-R and OW-406-R) is more enriched isotopically than the Down-Dip Plume Area (OW-401-R, OW-401-RD, OW-411-RD), northern portion of the Northern Plume Area (OW-112-R, OW-407-R) and the background groundwater. The groundwater from the Down-Dip Plume Area is also heavier than background groundwater. The bedrock groundwater samples from the Down-Dip Plume Area were collected from monitoring wells that are deeper than the majority of the other bedrock groundwater samples. The sample from monitoring well OW-401-R is much heavier (more negative values) than the other samples in the Down-Dip Plume Area. The isotopic signatures of these groundwater samples indicate that this deeper groundwater could be potentially mixing with older, isotopically heavier groundwater, possibly glacial recharge water, suspected to be contained in the deeper “regional” groundwater flow system.

The stable isotopes of the Site groundwater found in both the unconsolidated deposits and the bedrock appear to be mixing between two sources of water that had different recharge values. This postulated mixing line represents groundwater with different percentages of local or recent groundwater, which has the highest percentage in the unconsolidated deposits samples and the URI data set, and a “heavier”

17 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

isotopic signature representing an older “mean annual” isotopic value that may represent the deeper, regional flow system. As shown on Figure 18, the deeper bedrock groundwater samples from the Down- Dip Plume Area have a higher percentage of this older recharged groundwater than the more recently recharged groundwater, as exhibited by the majority of the unconsolidated deposit samples and the surface water samples. The highest percentage of the more recently recharged groundwater is found in the groundwater samples from the unconsolidated deposits in the FSA (OW-93-O), southern portion of the Northern Plume Area (OW-43 and OW-51) and the Central Area of the Site (OW-408-D and OW-409- D). This more recently recharged “isotopic” signature represents the local groundwater flow. As discussed in the recently submitted CSM, this local groundwater flow has a very short flow path from infiltration into the subsurface to discharge to the surface water bodies at the Site. The “older” recharged “isotopic” signature represents a longer groundwater flow path that is more characteristic of regional groundwater flow.

This older “isotopic” signature is expected to be similar to the isotopic signature of the Late Pleistocene (Wisconsinian-aged) glaciation predicted based on general circulation modeling (Ferguson and Jasechko, 2015). Ferguson and Jasechko (2015) modeled the δ18O of the Last Glacial Maximum ice sheet for Canada and the glaciated portions of North America using five different general circulation models. Lemieux et al. (2008) estimated that an average of 50% of the volume of the ice sheets themselves was recharged into the groundwater in the crystalline bedrock of the Canadian Shield (which is analogous to the crystalline bedrock found at the Site). The majority of the models predicted a δ18O value in this area between -10 to -14‰ for the New England region.

Assuming a δ18O value of -12‰ for the regional groundwater flow (Late Pleistocene glaciation influenced) and a δ18O value of -7.3‰ for the local groundwater flow, the following table summarizes the %Regional Flow System groundwater within each well sample. Calculations were made using the following equation.

(δ18O - δ18O ) %RFSGW = sample gw (δ18O - δ18O ) rfsgw gw

where: %RFSGW = percentage of Regional Flow System groundwater 18 δ Osample = oxygen isotopic composition of the well sample 18 δ Ogw = oxygen isotopic composition of the local flow system groundwater (-7.3) 18 δ Orf sgw = oxygen isotopic composition of the regional flow system groundwater (-12)

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%Regional Flow We ll d18O System Groundwater Overburden Wells OW-43 -7.89 13% OW-51 -7.94 14% OW-93-O -7.14 0% OW-111-O -9.42 45% OW-112-O -8.41 24% OW-200-O -9.04 37% OW-408-D -7.91 13% OW-409-D -7.97 14% Shallow Bedrock Wells OW-33 -8.43 24% OW-41 -8.02 15% OW-80 -8.59 27% OW-86 -8.55 27% OW-101-R -7.6 6% OW-105-R -8.15 18% OW-111-R -8.6 28% OW-112-R -8.69 30% OW-200-R -8.51 26% OW-404-R -8.16 18% OW-406-R -8.1 17% OW-407-R -8.65 29% SM W-2 -8.4 23% Deep Bedrock Wells OW-105-RD -8.35 22% OW-111-RD -8.81 32% OW-200-RD -8.36 23% OW-401-R -9.65 50% OW-401-RD -8.95 35% OW-407-RD -8.71 30% OW-410-R -8.7 30% OW-411-RD -8.87 33% SM W-3 -8.73 30%

The wells exhibiting the highest percentage of the Regional Flow System groundwater within each well group are shown in red. The average percentages of the Regional Flow System groundwater can be further categorized as follows.

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Average % Average % Well Type Local Regional Groundwater Groundwater

Unconsolidated Deposits 80% 20%

Bedrock 74% 26%

Shallow Bedrock 78% 22%

Deep Bedrock 68% 32%

This table demonstrates the following:

• % Regional Groundwater is generally higher in the bedrock compared to the unconsolidated deposits and generally increases with depth into the bedrock

• Similarity between the unconsolidated deposits (average-20%) and the shallow bedrock (average- 22%) further supports significant mixing and interconnection between these units

• Groundwater flow system at the Site appears to be dominated by local groundwater

The three bedrock wells (OW-401-R, OW-401-RD, OW-411-RD) containing the highest percentages of the Regional Flow System groundwater are all located within the Down-dip Area. The three shallow bedrock wells containing the highest percentages of Regional Flow System groundwater are located in the northern portion of the Northern Plume (OW-112-R, OW-407-R) and near the basin outlet within the dike structure (OW-111-R). The higher percentages for the two Northern Plume wells are consistent with the cation/anion data which suggests similarities between the Down-dip Area wells and the wells located in the northern portion of the Northern Plume. OW-111-R is also located near two key structural features in the bedrock (East-West Fracture Trace, Thermally-altered Zone) which are both potential conduits for upward vertical flow from and within the bedrock.

Select overburden wells (OW-111-O, OW-112-O and OW-200-O) exhibited higher percentages of the regional flow system groundwater ranging from approximately 24% (OW-112-O) to 45% (OW-111-O). These results are consistent with the current conceptualizations that overburden and bedrock groundwaters interact and that this interaction is variable across the Site and likely influenced by key structural features in the bedrock.

Elevated percentages of the Regional Flow System groundwater within the shallow bedrock (OW-111-R) and unconsolidated deposits (OW-111-O) suggests that deeper bedrock groundwater is upwelling and discharging through the shallow bedrock and overburden at the basin outlet. As noted above, both of these wells are located near key bedrock structural features (East-West Fracture Trace, Thermally-altered Zone) that are suspected conduits for vertical flow. Two other shallow bedrock wells located near the basin outlet (OW-80 and OW-86) also exhibited higher than average percentages of the Regional Flow System groundwater.

20 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

Figure 18 is annotated to show the concept of a local groundwater flow end-member whose isotopic signature more closely represents the isotopic signature of recent precipitation and a more regional groundwater flow end-member whose isotopic signature reflects Late Pleistocene glaciation recharged groundwater. The regional flow groundwater end-member likely occurs between -10 and -14 δ18O based on the results of the modeling discussed above. The variability of the mixing of Site groundwaters from these two sources can be seen by the variability in the isotopic signature of the groundwater samples collected from the Site. The isotopic signature of the Site groundwaters also likely varies depending on the variability in precipitation-related groundwater recharge and variability in the fluxes between the unconsolidated deposits and the bedrock. It has been shown that glaciation likely had a significant influence on groundwater conditions underlying the ice sheets (Ferguson and Jasechko, 2015). Meanwhile, the Site surface waters show variability likely related to variability in the degree that evaporation has influenced the isotopic signature and the influence of contributions from groundwater which typically has a lower isotopic signature.

The above table, detailing the % Regional Groundwater System Groundwater, and Figures 17 and 18 demonstrate the variability in the isotopic signature within the unconsolidated deposits and the bedrock at the Site. This variability is likely derived from the complex flow system at the Site, particularly within the fractured bedrock, which is dominated by the key structural features. These conditions result in variability in both groundwater flow paths and upward vertical flow both within the bedrock and between the bedrock and the unconsolidated deposits.

The URI stable isotope dataset, including surface water and groundwater samples collected in the Pawcatuck River Watershed, has a great correlation with the stable isotopes from the Site. As provided on Figure 19, the URI dataset “fills” in the gap of more enriched groundwater which matches the stable isotopic signature of the Site groundwater in the unconsolidated deposits, select bedrock groundwater samples and the surface water sample taken at Latham Brook. Based on this comparison, the URI data set appears to have sampled wells completed within the unconsolidated deposits or shallow bedrock.

Figures 20 and 21 present plan views of the δ18O and δ3H results for the shallow bedrock and deep bedrock wells. These plan view figures depict the areas of heavier isotopic composition that shows the areas within the shallow and deep bedrock that are likely to be more influenced by the deeper Regional Groundwater Flow System. Both figures show that the extent of the heavier isotopic groundwater is more extensive within the deep bedrock and supports a greater influence of the Regional Groundwater Flow System within the deep bedrock as would be expected. Relative to the principal geologic structures within the bedrock, both figures show that the heavier isotopic groundwater within the shallow bedrock occurs in close proximity to the North-South Weathered Relict Bedding Feature and the East-West Fracture Trace and to the north and east of these features within the Central Area of the Site. This distribution of the heavier isotopic groundwater within the shallow bedrock supports that these primary structural features are acting as conduits for the vertical migration of deeper bedrock groundwater into the shallow bedrock in response to the upward vertical gradients within the bedrock.

3.6 Vertical Comparison Summary figures providing the analytical and field parameters results, stiff diagrams, and the trilinear diagrams based on the analytical results at each location for the surface water samples and the groundwater samples are provided on Figures 22 through 29. The groundwater figures, with the exception of the Sentry Well figure, are presented by groups of well located within certain areas of the

21 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

Site. Samples were collected from eight well clusters to ascertain if different groundwater flow paths could be determined by any different ionic and isotopic signatures with depth within the bedrock. These well clusters are situated across the entire Site, including representat ive samples from each of the three identified fracture network blocks and the various Site areas. Figures 23 through 28 are summary figures for each of these eight well groupings. The following observations are presented by Site area and are based on comparison of the major and minor cations and anions and stable isotopes for co-located monitoring wells.

Northern Plume Area

• OW-406-R (Calcium-Chloride) is different from OW-101-R (Calcium-Bicarbonate) based on the concentrations of the major and minor cations and anions. Concentrations are generally higher at OW-406-R which could be indicative of slower groundwater velocities and longer residence time within the bedrock at the deeper depth at this location or more influence from the regional flow system groundwater. The isotope results appear to support this conclusion as the results for OW-101-R are closer to the shallow flow system groundwater (Figures 18 and 23).

• OW-407-RD (Calcium-Bicarbonate) is different from OW-112-R and OW-407-R (Calcium-Chloride) based on the concentrations of the major and minor cations and anions. The sample from OW-407- RD exhibits lower concentrations of many of the cations and anions and resembles the unimpacted, native bedrock groundwater. This is consistent with the vertical delineation of groundwater impacts at this location (Figure 25).

Down-Dip Area • OW-401-R and OW-401-RD are different based primarily on the isotope results. Although OW-401-R is the shallower well, it appears to be more influenced by the regional flow system groundwater than OW-401-RD given its location on the mixing line on Figure 18. Despite this difference, both of these wells plot further down the mixing line towards the Regional Flow System endmember than the background wells suggesting a greater influence from the regional flow system groundwater at both of these wells. Both of these wells were classified as exhibiting the impacted bedrock groundwater type (Calcium-Chloride) based on the cations and anions.

Dike Structure • OW-111-RD (Sodium-Chloride/Bicarbonate) is different from OW-111-R (Sodium-Bicarbonate) and OW-80 (Sodium/Calcium-Bicarbonate) based on the relative concentrations of select cations and anions and appears to be more influenced by the regional flow system groundwater given its relative location on the stable isotope mixing line on (Figures 18 and 26). The higher chloride concentration at OW-111-RD is likely due to the low concentrations of COCs in this well compared to the two shallower wells in the dike structure.

These differences seem to be driven by the variability in the degree of impact by anthropogenic compounds at these locations and the variability of the influence of the Regional Flow System Groundwater. It also seems that monitoring wells within slower flow regimes (e.g., dike and/or deeper bedrock) can exhibit higher concentrations of certain cations and/or anions due to longer residence times allowing greater dissolution of bedrock minerals.

22 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

3.7 Discussion of Individual Analytes During the process of the geochemical evaluation, some observations were made for individual analytes which are outlined in the following sections.

3.7.1 Chloride Chloride is the predominate anion in the groundwater for both the unconsolidated deposits and bedrock within the impacted groundwater areas. Based on the Site data collected between 2001 and 2013, background chloride concentrations are approximately 1.9 mg/L in the unconsolidated deposits (OW-81) and approximately 2.2 mg/L in the bedrock (OW-82). Within the impacted plume areas, chloride concentrations range from 10 to 29 mg/L in the unconsolidated deposits and from 23 to 1,700 mg/L in the bedrock. The increase in chloride can be contributed to biodegradation of the anthropogenic chlorinated organic compounds.

The sample at monitoring well OW-200-O has a chloride concentration of 32 mg/L which is the highest concentration in the unconsolidated deposits. It is suspected that since both sodium and chloride are elevated at this location relative to the other unconsolidated deposit wells sampled as part of this assessment, that road salt from nearby Log Road may be impacting the results at this location.

The most elevated concentrations of chloride (>100 mg/L) are located within the concentrated plume area (>1,000 ug/L total VOC) in the bedrock and include the following wells.

Chloride Well Concentration (mg/L)

OW-406-R 580 (North Plume Area)

OW-41 110 (North Plume Area)

OW-112-R 450 (North Plume Area)

OW-407-R 460 (North Plume Area)

OW-401-R 1,700 (Down-dip Plume Area)

OW-401-RD 350 (North Plume Area)

As noted previously, chloride is a biodegradation product of the reductive dechlorination process and the prevalence of significantly elevated chloride concentrations (greater than 15 times the background concentration) within the concentrated plume area in the bedrock is strong evidence that robust dechlorination of chlorinated VOCs is ongoing at the Site. Additionally, there should be a relationship

23 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

between the anthropogenic chlorinated organic compounds concentrations and chloride. Upon analyzing the relationships of total chlorinated ethenes vs. chloride and total chlorinated ethanes vs chloride, no apparent relationship existed. However, there is an apparent direct relationship (R2=0.75) between chloride concentrations and 1,4-dioxane concentrations (Figure 30). Since 1,4-dioxane does not contain chloride, one possible explanation is that 1,4-dioxane and the chloride (both “relatively stable or conservative” in groundwater) are representative of the downgradient plume extent.

The following figure snapshot shows the bedrock well locations exhibiting the unimpacted, native groundwater geochemical type (Calcium-Bicarbonate) or the dike geochemical type (Sodium-Bicarbonate or Calcium/Sodium-Bicarbonate) and chloride concentrations similar to the background values (i.e., less than 2.6 times the background concentration) for the Site and the bedrock plume delineation by key COCs as shown on Figure 4-33 from the recent CSM submittal. By comparison, chloride concentrations within the bedrock plume area are approximately 10 to 750 times the background concentration. Kaufman and Orlob (1956) conducted tracer experiments in ground water, and found that chloride moved through most of the soils tested more conservatively (i.e., with less retardation and loss) than any of the other tracers tested. This data supports that the area of elevated chloride concentrations at the Site is well defined by the current monitoring well network and is a strong indicator that the contaminant plume within the bedrock is also well defined. In addition, the chloride concentration at OW-407-RD in the Northern Plume Area is a strong indicator that the vertical extent of the contaminant plume is well-defined in this area.

g/L ~

3.7.2 Calcium Calcium is the predominate cation in the groundwater for both the unconsolidated deposits and bedrock. The calcium concentrations for the unconsolidated deposit wells are less than the average background concentration of 9.3 mg/L (NWIS database), except at locations OW-43 and OW-409-D. The concentrations at these two locations were 33 and 28 mg/L, respectively. The calcium concentrations within the naturally occurring or native bedrock groundwater samples ranged from 10 to 24 mg/L, whereas, “impacted” groundwater type (Calcium-Chloride) had much higher calcium concentrations

24 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017 ranging from 25 to 720 mg/L. Based on this difference, there appears to be an area of elevated calcium concentrations associated with the anthropogenic chlorinated organic compounds. The highest concentrations of calcium within the bedrock are located within the Concentrated Plume area (total VOC > 1,000 ug/L) area. The highest calcium concentrations within the unconsolidated deposits (OW-43 and OW-409-D) are located in an area of apparent preferential upwelling of groundwater from the underlying bedrock that appears to be associated with structural features within the bedrock.

3.7.3 Sodium For the unconsolidated deposits, sodium concentrations at OW-43 at 12 mg/L and OW-200-O at 17 mg/L were higher than the background groundwater concentration (NWIS database) of 11.7 mg/L. The sodium concentrations within the “impacted” bedrock groundwater were routinely higher than the unconsolidated deposits groundwater. The highest concentrations in the bedrock were found at OW-401-RD (Down-Dip Area; 140 mg/L) and OW-406-R (Northern Plume; 150 mg/L). The increased sodium is associated with the anthropogenic chlorinated organic compounds. Similar to calcium, the highest concentrations of sodium within the bedrock are located within the bedrock are located within the Concentrated Plume area (total VOC > 1,000 ug/L) area. In the general absence of anthropogenic impacts in the dike, the higher concentrations of sodium in the dike is either from a more significant presence of sodium-bearing feldspars and pyroxenes and/or the groundwater has a longer residence time within the dike to react with these minerals.

3.7.4 Sulfate All the sulfate concentrations in unconsolidated deposits groundwater were below the average background concentrations (NWIS database; 13.3 mg/L). The concentrations in these samples ranged from 6.4 to 12 mg/L. The majority of the bedrock concentrations were also below 13.3 mg/L. The bedrock wells in the FSA and Northern Plume had sulfate concentrations ranging from 14 to 20 mg/L, which are higher than the background concentration. Sulfate concentrations are much lower in the Down-Dip Area and Central Area of the Site. It appears that the sulfate concentrations in both the unconsolidated deposits and portions of the bedrock might be depleted due to sulfate reduction reactions resulting from the in-situ degradation of the anthropogenic organic compounds.

The concentrations of sulfate in the surface water are higher than in the groundwater at the Site. Therefore, it appears that another mechanism may be adding sulfate to the surface water system in addition to sulfate contributed by groundwater discharge. It is postulated that the sulfate may be coming from the wetland areas within and upstream of the Site as a result of sulfate reduction of sulfide compounds (e.g., hydrogen sulfide, iron sulfide) within the anaerobic sediments of the wetlands and potential contribution from atmospheric deposition, as well.

3.7.5 Alkalinity (Bicarbonate and Carbonate) Unlike the other previously discussed analytes, alkalinity for both the unconsolidated deposits and the bedrock are higher than the background concentration of 19.9 mg/L (NWIS database). Unconsolidated deposits monitoring well OW-200-O (4.6 mg/L) was the only well below the background concentration. The unconsolidated deposit alkalinity concentrations ranged from 27 to 98 mg/L. The native bedrock groundwater concentrations ranged from 32 to 75 mg/L while the “impacted groundwater” bedrock concentrations ranged from 41 to 460 mg/L. The highest concentrations are at OW-401-RD (Down-Dip Area; 180 mg/L) and OW-406-R (Northern Plume; 460 mg/L).

25 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

3.7.6 Dissolve d Iron Similar to alkalinity, all the samples for iron in the unconsolidated deposits were higher than the average background concentration of 0.1 mg/L (NWIS database) except OW-112-O and OW-200-O, which were both non-detect for iron. The concentrations ranged from 0.2 to 9 mg/L in the unconsolidated deposits. Some of the highest concentrations were found in OW-43 (5.9 mg/L) and OW-409-D (5.0 mg/L) and at OW-93-O (9 mg/L). The native “background bedrock groundwater” had iron concentrations below the background samples ranging from non-detect to 0.1 mg/L. The “impacted groundwater” had iron concentrations significantly higher than the background groundwater. The highest concentrations were found at OW-406-R (26 mg/L), OW-401-RD (11 mg/L), OW-101-R (5.7 mg/L), OW-41 (5.6 mg/L), and OW-93-O (3.2 mg/L). These wells are located within the FSA, Northern Plume, and Down-Dip Area. It appears that the dissolved iron is being generated through iron-reducing reactions associated with the anthropogenic chlorinated organic compounds and ongoing in-situ degradation processes. Iron is plentiful within the minerals of the schists and gneisses of the Nipsachuck Gneiss and Absalona Formation, and also within the diabase dike structure.

3.7.7 Silica Every unconsolidated deposits groundwater sample is above the average background concertation from the NWIS dataset (9.3 mg/L). The unconsolidated deposits groundwater concentrations ranged from 13 to 21 mg/L. The bedrock groundwater concentrations are also above the background with the samples ranging from 11 to 34 mg/L. It appears that there is no pattern for higher silica concentrations in either the “background” or “impacted” groundwater.

4.0 CONCLUSIONS The evaluation of the major and minor cation and anion data and the stable isotope data provided insight into the nature of the groundwater within both the unconsolidated deposits and bedrock and groundwater flow, particularly within the bedrock. Overall, the evaluation of these analytical results from the Fall 2015 Site-wide monitoring event support the following conclusions.

• Three groundwater types have been identified based on the geochemical results for the major and minor cations and anions. These types consist of the following:

o Calcium-Bicarbonate – unimpacted overburden and bedrock groundwater

o Calcium-Chloride – impacted by anthropogenic organic compounds Group 2 – Down-Dip Area and Northern Plume

o Sodium-Bicarbonate (and Calcium-Sodium-Bicarbonate) – minimally-impacted and unimpacted groundwater within the dike structure

• The locations of wells exhibiting the background, unimpacted geochemical type (Calcium- Bicarbonate) support the plume delineations as presented in the recently submitted Draft CSM. The geochemical type associated with the following wells support this conclusion.

o OW-407-RD, OW-200-R (Northern Plume)

o OW-105-R, OW-105-RD (Eastern Area)

26 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

o OW-111-R, OW-80 (Dike Structure)

o OW-86, OW-200-RD, SMW-2, SMW-3 (Sentry Wells)

o The distribution of chloride concentrations also supports the current plume delineations.

• Groundwater significantly impacted by anthropogenic organic compounds displays a distinct geochemical type (Calcium-Chloride). The following wells support this conclusion. Refer to Figures 21, 22 and 23.

o OW-404-R (FSA)

o OW-401-R, OW-401-RD, OW-411-RD (Down-Dip Area) and OW-406-R, OW-41, OW-112-R, OW-407-R (Northern Plume)

o This geochemical type is generally located within the Concentrated Plume area (TVOC > 1,000 ug/L).

o The similarities between the geochemistry of the Down-Dip Area wells and the Northern Plume wells is consistent with similarities noted in the nature of the COC impacts at these wells and may indicate a similar source and interconnectivity between these areas, possibly related to the North- South Weathered Relict Bedding Feature noted in the CSM (refer to Figure 4).

o Elevated concentrations of calcium, sodium, iron and chloride appear to be associated with the anthropogenic impacts at the Site and the geochemical changes associated with the ongoing natural degradation of contaminants. The highest concentrations of these four cations/anions occur within the Concentrated Plume area (TVOC concentrations > 1,000 ug/L).

• The geochemical type within the dike structure (Sodium Bicarbonate and Calcium-Sodium- Bicarbonate) is different from the other Site groundwaters and is likely related to the different mineralogy of the bedrock within the dike.

o This difference also suggests a sufficiently long residence time within the dike structure in order to alter the geochemical signature of the groundwater in the dike.

o The relatively limited areal extent of the dike structure relative to the surrounding host rock (granitic gneiss) suggests the possibility of slower groundwater velocities within the dike in order to support adequate residence time.

o The shift in the geochemical type for the groundwater in the dike structure relative to the other bedrock wells sampled is clearly evidenced on Figure 12 based on the analytical results for the three dike monitoring wells (OW-111-R, OW-80, OW-111-RD).

o The geochemical type for the groundwater at dike well OW-111-RD is further shifted due to the higher concentration of chloride at this location resulting from the natural degradation of CVOCs.

• Surface waters display a different geochemical type (Calcium-Sulfate) and variability in isotopic signature likely due to variable evaporative losses (ponded vs. flowing) and variability in the influence of contributions from groundwater discharges, which typically have a heavier isotopic signature.

27 Davis Site Performing Party Group Groundwater Geochemical Evaluation September 21, 2017

o In addition, ongoing geochemical processes within the wetland environment are likely influencing the geochemical signature of the surface waters, such as the potential for production of sulfate which was detected at higher concentrations in the surface water samples compared to the groundwater samples.

• Both the geochemical data and the stable isotope data suggest mixing between the unconsolidated deposits and bedrock groundwaters and that the degree of mixing varies across the Site.

o Similarity between the unimpacted, native groundwater type within both the unconsolidated deposits and the bedrock supports mixing between the two groundwaters. This concept is supported by the dominant upward vertical gradients at the Site and the presence of the Site within a groundwater discharge area.

o Elevated concentrations of calcium and chloride in the groundwater samples from overburden monitoring wells OW-43 and OW-409-D support upwelling from the underlying bedrock in the vicinity of key bedrock structural features.

o The variability in the isotopic signature of the unconsolidated deposit wells along the Davis Meteoric Water Line also supports this concept.

• Stable isotope results suggest that the unconsolidated deposit groundwater and bedrock groundwater are both mixing between two different water sources within distinct isotopic signatures [recent groundwater derived principally from precipitation (approximately -7‰ δ18O) and deeper, regional groundwater influenced by recent glaciation (postulated to be between -10 and -14‰ δ18O)].

o Majority of unconsolidated deposit wells have an isotopic signature closer to the recent groundwater end-member (Shallow Flow System Groundwater; Figure 18) suggesting a shallower flow component.

o Down-Dip Area groundwater appears to have a greater component of the deeper, regional groundwater (Regional Flow System Groundwater; Figure 18) resulting in a heavier isotopic signature.

o Portions of the Northern Plume Area (OW-112-R, OW-407-R, OW-407-RD) also appear to be more influenced by the deeper regional groundwater.

o Assuming that the recent groundwater isotopic signature (Shallow Flow System Groundwater) is - 7.3‰ δ18O and the deeper, regional groundwater (Regional Flow System Groundwater) is -12‰ δ18O supports the following assessment of %mixing between the two end-members.

. Majority of the unconsolidated deposits groundwater contains less than 15% deeper, regional groundwater and greater than 85% shallow, recent groundwater.

. The bedrock groundwater averages approximately 26% deeper, regional groundwater and 74% shallow, recent groundwater. The shallow bedrock monitoring wells average approximately 22% deeper regional groundwater and the deeper bedrock wells average approximately 32% deeper regional groundwater.

28 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

. % Regional Groundwater is generally higher in the bedrock compared to the unconsolidated deposits and generally increases with depth into the bedrock

. Similarity between the unconsolidated deposits (average-20%) and the shallow bedrock (average-22%) further supports significant mixing and interconnection between these units

. Groundwater flow system at the Site appears to be dominated by local groundwater

• The isotopic signature of the impacted groundwater varies depending on the area of the Site and with respect to certain key geologic features, such as the East-West Fracture Trace.

o Heavier groundwater is present within both the Down-Dip Area and the downgradient portions of the Northern Plume and further supports the similarities between these two areas.

o The plan view figures of the stable isotope results (Figures 20 and 21) also show that the heavier groundwater is widespread within the deeper bedrock suggesting greater interaction with the regional groundwater system.

o These figures also show that the heavier groundwater within the shallow bedrock is located in the immediate vicinity of the key bedrock structural features (“North-South Weathered Relict Bedding Feature” and East-West Fracture Trace) and supports that there is mixing of the shallow bedrock groundwater and the heavier deep bedrock groundwater in these areas, including the northern portion of the Northern Plume and the Central Area of the Site.

• The two previous conclusions support that mixing between the two end members (Figure 18; Shallow Flow System and Regional Flow System) is variable in both the unconsolidated deposit groundwater and the bedrock groundwater. This variability in mixing is likely the result of variability in groundwater recharge derived from precipitation, complexity of the bedrock groundwater flow regime and associated variability in the flux of groundwater from the underlying bedrock into the unconsolidated deposits.

o This conclusion is supported by the variability in the isotopic signature of all the well types (overburden, shallow bedrock, deep bedrock) along the Local Meteoric Water Line on Figures 17 and 18.

• Additional Site investigation into the nature of the dike structure at depth outside of the OW-111 area and additional monitoring points downgradient, to the east of the dike structure, would be beneficial to verify and validate the groundwater conditions at the Site and the flow concepts described in this technical memorandum.

o An additional borehole drilled and logged within the dike structure outside of the OW-111 area would demonstrate if the nature of the dike structure is consistent or not.

o Hydraulic monitoring of select existing monitoring within and proximal to the dike structure during the performance of any additional investigation activities could provide data relative to interconnectivity within the bedrock in the vicinity of the dike structure.

29 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

5.0 REFERENCES ESS Group and EHS Support. 2016. Draft Conceptual Site Model. Davis Liquid Waste Superfund Site. Smithfield, Rhode Island.

ESS Group. 2016. Fall 2015 Site-wide Groundwater Sampling Report. Davis Liquid Waste Superfund Site, Smithfield, Rhode Island.

Ferguson, G. and Jasechko, S. 2015. The isotopic composition of the Laurentide Ice Sheet and fossil groundwater. Geophysical Research Letters. Volume 42. Pages 4856-4861.

Kaufman, W.J. and Orlob, G.T., 1956. Measuring ground water movement with radioactive and chemical tracers: Am. Water Works Assoc. J., 48:559-572.

Toth, J. 1963. A theoretical analysis of groundwater flow in small drainage basins. Journal of Geophysical Research. Volume 68. Number 17. Pages 4795-4812.

Veeger, A. Personal Communication. Water Resources Center at the University of Rhode Island. April 2016.

30 Davis Site Performing Party Group Groundw ater Geochemical Evaluation September 21, 2017

List of Tables Table 1 Analytical Results from the NWIS database Table 2 Analytical Results from Davis Site Table 3 Summary Statistics for Overburden Wells Table 4 Background Concentrations for NWIS Bedrock Well and Summary Stats for Site Bedrock Wells Table 5 Summary Statistics for Surface Water Samples

List of Figures Figure 1 Site Location Map Figure 2 Site Plan and Monitoring Well Location Map Figure 3 Geological and Hydrogeological Conceptual Site Model Figure 4 Plan View of Bedrock Structures Figure 5 Histogram of CBE Results of the Background Groundwater Samples Figure 6 Histogram of CBE Results of the Site Groundwater and Surface Water Samples Figure 7 Boxplot of Analytes from Background Ground Water Samples Figure 8 Generic Trilinear Diagram Figure 9 Trilinear Diagram for Background Groundwater Samples Figure 10 Trilinear Diagram for Surface Water Samples Figure 11 Trilinear Diagram for Unconsolidated Deposits Groundwater Samples Figure 12 Trilinear Diagram for Bedrock Groundwater Samples Figure 13 Conceptual Trilinear Diagram Figure 14 Stiff Diagrams for Surface Water Samples and Unconsolidated Deposits Groundwater Figure 15 Stiff Diagrams for Shallow Bedrock Groundwater Figure 16 Stiff Diagrams for Deep Bedrock Groundwater Figure 17 Stable Isotopes δ18O vs δ3H Figure 18 Interpretative Stable Isotopes δ18O vs δ3H Figure 19 Stable Isotopes δ18O vs δ3H With Data from URI Figure 20 Plan View of δ18O Results Figure 21 Plan View of δ3H Results Figure 22 Summary of Surface Water Data Figure 23 Summary of Groundwater Data from Former Source Area Figure 24 Summary of Groundwater Data from Down-Dip Plume Area Figure 25 Summary of Groundwater Data from Northern Plume Area Figure 26 Summary of Groundwater Data from Dike Area Figure 27 Summary of Groundwater Data from Central Area Figure 28 Summary of Groundwater Data from Northern Portion of Site Figure 29 Summary of Groundwater Data from Other Sentry Wells Figure 30 1,4-Dioxane vs. Chloride Groundwater Samples

List of Attachments Attachment A Geochemical Type Pie Charts Attachment B Stiff Diagrams Attachment C URI Dataset

31

Tables

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TABLE 1 - SUMMARY OF BACKGROUND GEOCHEMICAL DATA ~€$g rou P NWIS DATABASE 819 Type Well Well Well Well Well Well Well Well Well Unit UD UD UD UD B UD UD UD UD

Location ID RI-GLW 293 RI-GLW 28 RI-BUW 399 RI-BUW 399 RI-BUW 69 RI-BUW 284 RI-GLW 298 RI-NSW 310 RI-NSW 158 ~ Depth (feet) Units 16 18 50 50 202 16 36 64 21 -

CATIONS - Calcium mg/L 5 7.3 4.82 5.83 12 5.5 3 4.5 7.1 Iron mg/L 0.05 0.05 0.393 0.24 0.01 0.03 0.19 0.03 0.04 Magnesium mg/L 0.5 1.2 0.96 1.16 1.4 0.8 0.3 0.8 1 Potassium mg/L 1 1.2 1.18 1.26 1.2 1 0.8 0.8 1.4 Sodium mg/L 2.4 8 8.68 12.1 8 2.3 2.9 3.6 26 ANIONS

~Silica mg/L 6.9 4.8 13.3 13.7 19 8.3 10 12 7.4 Bicarbonate (as CaCO3) mg/L 10 12 13 12 48 4 16 16 8

Bicarbonate (as HCO3) mg/L 12.2 14.6 15.9 14.6 58.6 4.9 19.5 19.5 9.8 Chloride mg/L 5.4 11 13.4 20.5 7 4 1 3.8 45 Sulfate mg/L 7.2 16 5.77 6.44 3.8 12 2.2 5 9.4 Charge Balance Error -8.6% -2.3% -1.1% 0.1% -6.1% 2.7% -9.2% -6.3% -0.6% OTHER PARAMETERS Temperature oC 9 11 11.1 10.6 12 12 20 10 10 Conductance μS/cm 48 98 88 120 115 51 39 51 193 I pH I I 6.6 I 6.4 I 5.6 I 5.6 I 7 I 5.8 I 6.6 I 6.6 I 6.4 _J NOTES: NA - Not Applicable Unk - unknown; not reported CBE exceeding +/-20% are shaded UD - unconsolidated deposits B - bedrock

Page 1 of 4 4\ES TABLE 1 - SUMMARY OF BACKGROUND GEOCHEMICAL DATA •fgrosup NWIS DATABASE

Type Well Well Well Well Well Well Well Well Unit UD UD UD UD UD B UD UD

Location ID RI-CUW 409 RI-CUW 409 RI-LIW 335 RI-BUW 54 RI-NSW 51 RI-LIW 4 RI-CUW 3 RI-LIW 383 - Depth (feet) Units 75 75 107 16 68 300 50 62 ~ - CATIONS ~ - Calcium mg/L 16 14 26 4.3 8.6 13 11 22 Iron mg/L 0.03 0.01 0.01 0.14 0.07 0.01 Magnesium mg/L 3.5 3.2 4.8 1 1 1.4 4.1 Potassium mg/L 3 3.7 3.4 1.3 4.8 Sodium mg/L 22 19 20 5.8 22 ANIONS

Silica mg/L 7.6 8.6 12 7.3 7.8 6.9 9.6 - Bicarbonate (as CaCO3) mg/L 40 37 36 10 15 33 30 60

Bicarbonate (as HCO3) mg/L 48.8 45.1 43.9 12.2 18.3 40.3 36.6 73.2 Chloride mg/L 31 21 34 11 6 12 33 Sulfate mg/L 23 27 36 7 6.2 19 18 24 Charge Balance Error -0.7% -0.3% 4.4% -5.9% -7.3% -23.9% -32.6% -2.2% OTHER PARAMETERS Temperature oC 9 11.3 11.3 11 14.3 Conductance μS/cm 241 220 305 73 85 173 149 280 !...pH I I 6.9 I 6.2 I 6.2 I 6.4 I 6.9 I 7.1 I 7 I 6.4 J NOTES: NA - Not Applicable Unk - unknown; not reported CBE exceeding +/-20% are shaded UD - unconsolidated deposits B - bedrock

Page 2 of 4 TABLE 1 - SUMMARY OF BACKGROUND GEOCHEMICAL DATA ffiSg rou P NWIS DATABASE -

Type Well Well Surface Water Surface Water Surface Water Surface Water Surface Water Surface Water-

~ Unit UD UD - SPRAGUE TARKILN BROOK TARKILN BROOK TARKILN BROOK TARKILN POND TARKILN POND RESERVOIR Location ID RI-BUW 149 RI-BUW 9 Depth (feet) Units 32 46 NA NA NA NA NA NA CATIONS Calcium mg/L 4.6 11 2.9 3.6 3.3 3.5 2.9 4.4

Iron mg/L 0.01 0.25 0.3 0.86 0.32 1.1 0.6 1.3 -

Magnesium mg/L 1.1 2.3 0.59 0.47 0.7 0.61 0.56 0.88 - Potassium mg/L 1 3.5 0.7 0.8 0.9 0.8 1.1 1.3 Sodium mg/L 5.3 15 3.7 4 4.7 5.2 4.6 11 ANIONS Silica mg/L 10 10 3 7 8.8 2

Bicarbonate (as CaCO3) mg/L 12 18 7 6 9

Bicarbonate (as HCO3) mg/L 14.6 22.0 8.54 7.32 10.98 Chloride mg/L 9.3 23 5.1 7 7.5 8.4 7.1 14 Sulfate mg/L 7 19 7 4 6.7 5 6 8 Charge Balance Error -5.8% 2.9% OTHER PARAMETERS Temperature oC 9 10 14 20 20 Conductance μS/cm 66 178 42 46 52 I pH I I 6.4 I 6.4 6.4 I 6.5 I 6.8 I 6.4 I 6.4 I 7 J NOTES: NA - Not Applicable Unk - unknown; not reported CBE exceeding +/-20% are shaded UD - unconsolidated deposits B - bedrock

Page 3 of 4 TABLE 1 - SUMMARY OF BACKGROUND GEOCHEMICAL DATA oups NWIS DATABASE - Type Surface Water Surface Water Surface Water Surface Water Surface Water Surface Water Surface Water Unit SPRAGUE WOONASQUATUCKET WOONASQUATUCKET STILLWATER STILLWATER WATERMAN WATERMAN RESERVOIR RESERVOIR RESERVOIR RESERVOIR RESERVOIR RESERVOIR RESERVOIR Location ID (UPPER) Depth (feet) Units NA NA NA NA NA NA NA CATIONS Calcium mg/L 4.2 7.9 7.3 7.8 6.8 5.4 4.8

~Iron mg/L 0.48 0.53 0.74 0.83 1.2 0.71 0.28 Magnesium mg/L 0.85 1.5 1.6 1.5 1.5 1 0.89 Potassium mg/L 1.6 1.7 2 1.8 1.6 1.8 Sodium mg/L 9.9 1.97 1.75 23 19 10 9.2 ANIONS Silica mg/L 4 3.2 1 3 2.4 2.2 4.2

Bicarbonate (as CaCO3) mg/L

Bicarbonate (as HCO3) mg/L Chloride mg/L 14 35 36 35 35 17 13 Sulfate mg/L 8 8.5 8.9 9.6 12 6 6 Charge Balance Error OTHER PARAMETERS Temperature oC 23.7 7.3 23.8 7.6 Conductance μS/cm 179 178 181 175 I pH I I 6.9 I 7.2 I 7.5 I 7.4 I 7.4 7.3 I 7.2 I NOTES: NA - Not Applicable Unk - unknown; not reported CBE exceeding +/-20% are shaded UD - unconsolidated deposits B - bedrock

Page 4 of 4 TABLE 2 - SUMMARY OF CATION/ANION AND STABLE ISOTOPE ANALYTICAL RESULTS -~~e:B Fall 2015 Site-wide Monitoring Event W!g roup Davis Liquid Waste Superfund Site

Designation UD Well UD Well UD Well UD Well UD Well UD Well UD Well UD Well Sample Location OW-43 OW-51 OW-93-O 0W-111-O OW-112-O OW-200-O OW-408-D OW-409-D Sampling Date 42312.00 42312.00 42317.00 42305.00 42311.00 42297.00 42310.00 42310.00 Matrix Water Water Water Water Water Water Water Water CATIONS (mg/L) Aluminum ND ND ND ND ND 0.31 ND ND Calcium 33 8.2 5.1 8.30 4.4 6.7 9 23 Iron 5.9 7.2 9 0.21 ND ND 0.15 5 Potassium 4.6 1.9 1.2 2.6 1.9 1.1 4.9 3.8 Magnesium 2.5 1.5 0.83 3.6 0.62 1 1.5 2.2 Manganese 3.5 1.9 0.65 0.019 0.0059 0.056 0.68 1.6 Sodium 12 5.2 2.8 4.4 3.3 17 5.9 7.4 ANIONS (mg/L)

Silica (SiO2) 21 15 17 20 13 8.5 13 15

Alkalinity, Bicarbonate (as CaCO3) 98 27 13 35 28 4.6 35 52

Alkalinity, Bicarbonate (as HCO3) 119.56 32.94 15.86 42.70 34.16 5.61 42.70 63.44 Chloride 18 6 3.9 3.5 4.4 32 10 29

Alkalinity, Carbonate (as CaCO3) ND ND ND ND ND ND ND ND Sulfate 12 12 7.8 12 6.4 8 6.8 11 Charge Balance Error 2.1% 8.4% 21.3% -3.5% -27.7% 1.1% -6.6% -2.5% STABLE ISOTOPES (per mil (VSMOW)) Oxygen-18 -7.89 -7.94 -7.14 -9.42 -8.41 -9.04 -7.91 -7.97 Deuterium-3 -50.20 -50.80 -47.60 -59.30 -52.00 -56.60 -48.90 -50.00 NOTES: ND - not detected EPW - Eastern Ponded Wetland NW - Northern Wetland LB - Latham Brook UD - Unconsolidated Deposits CBE exceeding +/-20% are shaded

Page 1 of 4 TABLE 2 - SUMMARY OF CATION/ANION AND STABLE ISOTOPE ANALYTICAL RESULTS Fall 2015 Site-wide Monitoring Event r o up- Davis Liquid Waste Superfund Site

' Designation Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Sample Location 0W-33 OW-41 OW-80 OW-101-R OW-105-R OW-105-RD OW-111-R OW-111-RD OW-112-R Sampling Date 42307.00 42312.00 42305.00 42313.00 42304.00 42304.00 42305.00 42305.00 42311.00 Matrix Water Water Water Water Water Water Water Water Water - CATIONS (mg/L) Aluminum ND ND ND ND ND ND 0.087 0.08 ND Calcium 21 74 10 43 11 21 9.1 15 190 Iron 0.079 5.6 0.029 5.7 ND ND 0.022 0.096 0.029 Potassium 4.3 6 2 5 1.5 2.5 3.2 2.6 7.4 ~ Magnesium 1.9 4.9 0.44 3.7 0.74 1.5 0.39 0.79 6.6 ' Manganese 0.21 4.1 0.0041 3.6 ND 0.0018 0.0016 0.0016 1.4 Sodium 7.7 31 13 20 4.1 11 16 27 68 ANIONS (mg/L)

Silica (SiO2) 11 26 22 24 13 21 21 31 8.4

Alkalinity, Bicarbonate (as CaCO3) 48 130 42 120 49 68 44 32 48

Alkalinity, Bicarbonate (as HCO3) 58.56 158.60 51.24 146.40 59.78 82.96 53.68 39.04 58.56 Chloride 23 110 4.3 28 3.5 3.2 5.8 24 450

Alkalinity, Carbonate (as CaCO3) ND ND ND ND ND ND ND 14 ND Sulfate 8.3 17 9.5 14 5.4 12 9.5 20 15 Charge Balance Error -3.5% -0.9% -0.2% 4.2% -18.1% 0.4% 1.3% 8.8% -2.7% STABLE ISOTOPES (per mil (VSMOW)) Oxygen-18 -8.43 -8.02 -8.59 -7.60 -8.15 -8.35 -8.60 -8.81 -8.69 Deuterium-3 -51.70 -50.30 -52.70 -48.30 -47.80 -50.20 -52.40 -54.60 -53.40 NOTES: ND - not detected EPW - Eastern Ponded Wetland NW - Northern Wetland LB - Latham Brook UD - Unconsolidated Deposits CBE exceeding +/-20% are shaded

Page 2 of 4 TABLE 2 - SUMMARY OF CATION/ANION AND STABLE ISOTOPE ANALYTICAL RESULTS Fall 2015 Site-wide Monitoring Event r o up- Davis Liquid Waste Superfund Site

Designation Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Bedrock Well Sample Location OW-200-R OW-401-R OW-401-RD OW-404-R OW-406-R OW-407-R OW-407-RD OW-410-R OW-411-RD Sampling Date 42297.00 42313.00 42314.00 42317.00 42313.00 42311.00 42311.00 42310.00 42313.00 Matrix Water Water Water Water Water Water Water Water Water - CATIONS (mg/L) Aluminum ND ND ND ND ND ND ND ND ND Calcium 24 46 720 25 300 200 19 23 150 Iron ND 0.23 11 3.2 26 0.23 0.069 ND 0.22 Potassium 2.4 4.6 4.4 4.5 18 8.2 0.65 3.9 5.7 Magnesium 0.56 7.2 34 1.6 22 6.6 0.47 1 10 Manganese 0.00048 0.6 4.5 2.8 16 1.9 0.034 0.049 1.2 Sodium 6.1 15 140 23 150 77 13 14 48 ANIONS (mg/L)

Silica (SiO2) 9.5 15 15 17 34 8.7 12 13 26

Alkalinity, Bicarbonate (as CaCO3) 66 46 180 41 460 50 71 45 92

Alkalinity, Bicarbonate (as HCO3) 80.52 56.12 219.60 50.02 561.20 61.00 86.62 54.90 112.24 Chloride 4.1 98 1700 55 580 460 2.2 32 350

Alkalinity, Carbonate (as CaCO3) ND ND ND ND ND ND ND ND ND Sulfate 8.2 4.3 3.7 17 ND 20 4.2 8.1 0.86 Charge Balance Error -1.1% -1.1% -6.3% -0.2% -0.5% -0.8% 0.1% -0.8% -5.1% STABLE ISOTOPES (per mil (VSMOW)) Oxygen-18 -8.51 -9.65 -8.95 -8.16 -8.10 -8.65 -8.71 -8.70 -8.87 Deuterium-3 -53.20 -63.60 -55.00 -49.60 -50.10 -53.30 -54.00 -54.10 -54.30 NOTES: ND - not detected Ca EPW - Eastern Ponded Wetland NW - Northern Wetland LB - Latham Brook UD - Unconsolidated Deposits CBE exceeding +/-20% are shaded

Page 3 of 4 TABLE 2 - SUMMARY OF CATION/ANION AND STABLE ISOTOPE ANALYTICAL RESULTS Fall 2015 Site-wide Monitoring Event Davis Liquid Waste Superfund Site

Designation Sentry Well Sentry Well Sentry Well Sentry Well Surface Water Surface Water Surface Water Sample Location OW-86 OW-200-RD SMW-2 SMW-3 EPW NW LB Sampling Date 42303.00 42300.00 42300.00 42303.00 42318.00 42318.00 42318.00 Matrix Water Water Water Water Water Water Water CATIONS (mg/L) Aluminum 0.084 ND ND ND ND 0.24 ND Calcium 20 27 17 20 9.4 29 14 Iron 0.065 ND ND ND 1.1 3.7 0.17 Potassium 1.7 1.8 3 1.1 3.3 1.8 2 Magnesium 0.87 0.5 0.64 1.3 2.3 2.4 2.9 Manganese 0.0048 0.021 0.00099 0.038 0.34 1 0.26 Sodium 4.2 5.6 6.2 8.2 4.7 6.1 7.5 ANIONS (mg/L)

Silica (SiO2) 8.1 14 16 16 4.6 18 14

Alkalinity, Bicarbonate (as CaCO3) 53 74 47 52 10 2.4 16

Alkalinity, Bicarbonate (as HCO3) 64.66 90.28 57.34 63.44 12.20 2.93 19.52 Chloride 2.9 2.8 3 3.6 7.3 5.5 11

Alkalinity, Carbonate (as CaCO3) ND ND ND ND ND ND ND Sulfate 9 8.8 10 14 23 76 31 Charge Balance Error -0.8% -1.8% 0.6% 2.0% 6.1% 9.3% 2.1% STABLE ISOTOPES (per mil (VSMOW)) Oxygen-18 -8.55 -8.36 -8.40 -8.73 -3.20 -5.94 -6.84 Deuterium-3 -52.10 -51.60 -51.80 -53.10 -22.40 -35.00 -41.40 NOTES: ND - not detected EPW - Eastern Ponded Wetland NW - Northern Wetland LB - Latham Brook UD - Unconsolidated Deposits CBE exceeding +/-20% are shaded

Page 4 of 4

Figures

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!° (!

Path: G:\GIS-Projects\D164-Davis\00-mxd\D164_Figure_1-1_Project_Locus.mxd

LOG ROAD

BAYBERRY RD

Site

Stillwater Reservoir (Stump Pond)

Drawing Date:2015/04/20

0 500 1,000 2,000 Feet

© 2015 ESS Group,Inc.

Davis Liquid Waste Superfund Site Site Locus Map ($ Smithfield, Rhode Island group 1 inch = 2,000 feet Legend Approximate Extent of Former Source Area (FSA) e V ' e Source: 1) USGS, 1:24,000 Topo, 2012 - Figure 1-1 ~-~ ...... ___---- - ...... ~ ...... _ z --- " ------...... , ,__ ...... _ ...... -...... 1 __: :__---::---:,, / ,.,../------...... -----...... __ __ rn '- 's 's LEGEND: l -- ...... / /.,,,,,,...... ffl ...... \ \ ' \. --- -- '--- I ,,,- r ------..... '- -...., ..._ ___ _ \ \ I ,,,- .,, ------. ' '- -.... ' OW-200-0 UNCONSOLIDATED DEPOSIT f~ ------.... , "\ \ \ ' '--. To Davis Residence / .r--. ' ' ...... _ I I I ,,,,------...... , \ " ...... ______) 8>, , ' , ' , \ ...... ______-- ...... \ I ~ MONITORING WELL ~ / / / / / ~_', I' \ ' ', ----...... , __ OW-200-R ------. \ \ '\ ---- ...._ "\I \ / I ( ..... , , _ __.. \ ...._ - ~ ------BEDROCK / -- ...... __ ) \ I I / / I/ I --- \ ...... _ --- - / '---- -..... J I MONITORING WELL ,,,.---~ -450- ____ 1,,,,,,,. /I / ,-- ...... // / / ' ,____ ~ / / / I --.... OW-200-RD• ______.,,,. / ...... BEDROCK SENTRY WELLS ------// / -E,)- ( '----. "*swG-1 SURFACE WATER GAUGING LOCATION // J ' ------=----,,,- ----~ --.,,,.-I ~--- // , __ _ ------= ROADS (PAVED) .. ... ROADS (UNPAVED) ...... / / ow-oa ...... DELINEATED WETLAND AREAS (DASHED WHERE APPROXIMATE) / ...... D / ...... I ...... POND (APPROXIMATE) \ ...... D ...... APPROXIMATE LIMIT OF SATURATED ..._ -- -- UNEXCAVATED SOIL ...... (FORMER SOURCE AREA) ...... ----) APPROXIMATE LOCATION OF ...... DIKE STRUCTURE ...... I '...._ • OW-00:--, OVERBURDEN TRANSECT ... .. A OW-011 ' -.... ______OW-008 .,,,. - - .. -v ,,,,,,,,.---- OBT-1 / ---- OW-079 , "' ., / --- OVERBURDEN TRANSECT / II + + + + + + + + + + + + + + + + / / -.fr OBT-2 / -- / + + + + + + + + _m()W-410-R /, ., + + ., :it: -----__ _,,,. // NOTES: / / ...... ------\ + ~ /~ ~-- / 1. BASE PLAN HAS BEEN COMPILED FROM SITE / ...... OW-110-R - ow=-mr-""' - -- -­ \ SURVEYS CONDUCTED BY MARK N. NYBERG ------I ~ w-=-~-~-) ASSOCIATES, INC. (DECEMBER 2001; MAY 2003, (.,,,.-) I ow-11 0 ...----;------...=-::-::-r:___·-:=-=~~ ...._ :.:.:~--, ·...; REVISED AUGUST 2003 AND DECEMBER 2003; __ ,.,,,. t' /' > I AND OCTOBER 2008), SITE SURVEYS / '-- ..._____ ./ ' -- ( CONDUCTED BY DIPRETE ENGINEERING 2 in ------~------~ ------...-_...... ,___----~..,_ "'!!!I!!,.. _ ....__ ------__ __./ /_ l. ) (NOVEMBER 2012, OCTOBER 2013 AND APRIL N ,,,,--450 ---- ' ...... 2015), AND WOODWARD-CLYDE FINAL I - __.,.,,. --- - ...... --...., o -- PRE-DESIGN ENGINEERING REPORT II ...... ', - -..._ ...... _____ ...... ~------(OCTOBER 1993). =1 ------' 0 ) ...... , ...... _ ----.., LL ,,,, --~ ~ '-.....,_ ...... _ -...... _ ....._ 2. ** REPLACEMENT WELLS INSTALLED IN THE / ') I / 4 ' '' ' ' - - - [ :~ (-----\ ) / .,,,.- 50, ') ', ', ~ \ \ GENERAL LOCATION OF WELLS DECOMMISSIONED DURING SOURCE ~ ', \. ) / __,.,,,.. / \ I \ I 1 REMEDIATION. ~~ ', '---...... _ __ ,,,. _,,,,. II / / (/ \ \..._..._ '--..._ / ,,,- ow-ci'§§....~-OW I g 2 \ ', I I I ,-, \ -~' I /,,,. __,.,,,.. ~ ...,..- / 3. DIKE STRUCTURE LOCATION BASED ON c'-.iin \. '--- ,,,. I / / , J ( ) \ / .,,,. ) I "' I -.... - ,,,- / ...._ J ---- I I I ----ow-024 ,.,,,. \ "' / APPROXIMATE INTERPRETED LOCATION OF ~ oo '-.... ---- I ( / , --- ,,,.- _, I I .- I ,I I ·;;:o I -...... _____ ./ / / / ~ ,__ ---.,,...... ,,.....-- .- ---- _,,...,...... - / / / / / 7 r-, '::,._;!:, _..- ,,,,.,,,.,,,. / DIORITE DIKE (BASED ON GEOPHYSICS) ,no ____ ,.,,,. I ------,,,,,,,, / / i , i ,,,,..,.. (SOURCE: WOODWARD-CLYDE CONSULTANTS, ~i ! / 1------/ .,.-. \ '-- / I / ,--- FIGURE G-2, DATED: 11/23/1992), APPROXIMATE ~Ei / - - - j \ I ------.,,,..,,,. __,.,,,.. /"' // / \ / / / LOCATION OF DIORITE DIKE . --- ) ;------_____ .,,,. ( ------/ I ,,,.I / ------I -::___ _,,,,./ (SOURCE: CAMP DRESSER & MCKEE, INC., 1, :r:w:: /;----...... ______~ / / / --- ..,.. --- / / / /, z ~ I I ,---- / ,,,..- I / / ,.,,,.---...._ / FIGURE 4-1, DATED: JANUARY 1986) AND / ,,,------I I I - --;; ,,.-, \ I (,,. I/ / / _,,./ '..._ / FINDINGS DURING HISTORIC AND RECENT ~ 1 / w c5 /,,,- /-...... / / I r ~ / // \ I I 1 / / / \ / DRILLING ACTIVITIES. ~ ~ 1 I ...... __ ,.,,,..- / .,, ,,, I - / / \ /

Davis Liquid Waste Superfund Site Site Plan and Monitoring Well Smithfield, Rhode Island Location Map ($ Project No. D164-005 group Scale: 1"=300'

.,.,\I .rmf'TT'"'I al e; r, HI ng 0 300 FEET & &I l '"'I , ':J 9,Pl"Vlf'Q. Figure 1-2

W estern Dike Structure Eastern fra cture Network Fracture Network Fracture Network

Local Ground w ater Loca.l Groundw ater Recharge Are.a Recharg e Are,a

++ u. Unconsolidated Deposits Upland Valley Up:land Eastern Ponded Wetlands (overburden ) 5 - 40 ft (Head Watersto the Unnamed Stream) , ,_,,,,,.-~· - · - - - - - ,,., ,., I ,. ... ,.. / 1 Groundw ater ,,' I • / \ 1 : Flowstothe , \ 1 : Lath am Brook \ \ I: Dow nstream of \ : Stte \ . \ \ \ f, \ \ :\' \ 4 I \ : \ ,,.. , I \ Horicanta l \ \ Fracture Absalona Formation \ \ bedrock \ \ \ \ \ \ predominantly gneiss \ \ EB \ \ \ \ \ \ \ a;4{)0 ft \ \ \ \ \ \ \ JI \ . .. a,· . . ~ ' \ \ \ 11\ \ \ , \ . ·..::,c:. \ \ a \ \ ' ;' \ \. ', ... l,e;JE11cl: \ ,•I\ \ . .a>· . \ + .·. fJ!· . Wa.ter-t · g, ll!OMOO.~ fraetllJJe \ (13• \ Dike Structure Local...... _\ __ _.... , ',\ .. ·.a .. -. . ro. - \ No fl ow or Limned Ground w ater Flow ' , \ ,,..._____ >o \ Flow Bound ary Up1Yard \ W atei-te - g, ear ve -... racill.!Je \ \ Head Grad1ent \ \ \ \ \ \ \ d'A•ater tlowisto tl1e nor1h I \ \ nortllea:st (into tile ff,1111e page} \. \ \ \ ff) \ \ \. Zooe of 'A'e

Figure 3 Geological and Hydrogeological Conceptual Site Model (Figure 3-3 of 2017 Draft Final CSM)

' ' . ,, ' / - I /' .....______- -_::-45-c;a..edrock Foliatio ( I / -- Dip Eastward 3 _,, I ~~::::;::~::::--t------

Western Fracture Network

,, ,,­ + .. + + ... • ... • + ... + ...... Dike Structure Fracture Network -~4so ------0.__ --') -~ / ,,-4so, Eastern / / Fracture / / 300FEET / -,- ( -.... Network Scale / / , ______, ( -­ _.. ----- / - I ' ,------,,..-- /

Figure 4 Plan View of Bedrock Structures (Figure 3.2 of 2017 Draft Final CSM)

co

'-3" en I]) 0.. E ro (f) .._ (") 0 '- I]) ..0 E z:::J N

0 ------______: ______:______------

-30 -20 -10 0 10 20 30

Percent Difference {%)

Figure 5 Histogram of CBE Results of the Background Groundwater Samples

0 ,,---

(I)

(/) IV 0.. E ro <.O lf) ...... 0 '- IV ..0 E ::J z -s:r-

N n . .

...... 0 iJ. . O ...... Jd . . . iJ ... . •

-30 -20 -10 0 10 20 30

Percent Difference (%)

Figure 6 Histogram of CBE Results of the Site Groundwater and Surface Water Samples.

0

_J OJ E 0 C "1" :p0 c~ (I) u C 0 0 0

0 N 0

I I I I I I I ______j___ I I ------9------'-- rn-- -- 0 -- s±s

Bicarbo11ate Chtoride Sulfate Calcium Magnesium Sodium Potassiium Silica Iron

A11al¥fe

Figure 7 Boxplot of Analytes from Background Overburden Ground Water Samples

Figure 8 Water Water Type 20% 20%

Type

O 4

!S 40%

% %

0 8 Chloride 60% 60% ‐ Water

80%

.

% %

0 Bicarbonate 6 ‐ Sodium Type

!Cl

% %

Sodium 0 Sulfate % 4

-

‐ 20

% 20 % %

20 40

\ 3

O

C

g

%

+ % %

M 3 ! 0

Calcium

40

% % 2

a + 0 CO

C 4 H 60 ! !

%

0

6 % %

60 80

% 80 % 80

Piper Diagram Diagram Piper

% %

0% 80 8 Diagram Generic Trilinear

% % % %

0

6 % 80

60

I l

C

% %

! % %

0

+ K

6

40

4 % + 0%

O 0 a 2 S 4

! !N

% % % %

0 0

2 % 4

I 20

% %

0 2 % 40 - !Ca

Water % 60 ~ Type 80% 80%

60% %

80

g g

M ! 40% I Bicarbonate ‐ 20% 20% Calcium Support S EHS Figure 9 20%

4

O 40%

S M

% %

0 8 60%

80%

% %

M 0 6 M M M M M M M Cl

M

M M

% %

0

% M 4

20 -~

%

0 2 % % M 20 40

\

g 3 O

% K

% %

0 C

M 0 4 2 + % H % Ca 40 60 M M

\

%

0

6 % %

60 80

%

0 8 % 80 M M M M M M M M M M M

Piper Diagram Diagram Piper

Trilinear Diagram for Background Groundwater Samples Trilinear % %

0 % 8 80 M

M

% % % %

0 0

6 % K 8 60

M

I l

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20

S 4 N

% % % %

0 0

2 4 M

I %

20

% %

0 2 % 40 M - M M M M M Ca M M M

M %

M 60 K ~ M 80% M

60% %

80

g g M 40% M 20% Support – Overburden Well Overburden Well – – Bedrock Well Well Bedrock – K M S EHS Figure 10 20%

4

SO 40%

% %

0 8 60%

80%

% %

Sulfate) 0 6 Water

J Cl

J J

% %

0

% 4

0 -~

Surface (Calcium ‐ 2

%

0 2 % % 20 40

\

g I 3 O %

% %

0 C

M 0 4 2 + % H % Ca 40 60

I

%

0 6 % % 60 80

Northern Wetland Wetland Northern

%

0 8 % 80 J J J

Piper Diagram Diagram Piper

% %

0 % 8 Samples Diagram for Surface Water Trilinear

80

% % % %

0 0

6 % 8

60 Latham Brook Latham Wetland Ponded Eastern

I l

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20

S 4 N

% % % %

0 0

2

I % 4

20

% %

0 2 % 40 - Ca

% 60 J ~ J 80%

60% %

80

g g J M 40% 20% Support S EHS Figure 11 Figure 11 20%

4

O 40%

S M

% %

0 8 60%

80%

% %

0 6 ed Deposits Groundwater Samples Cl

M

% %

0 % 4

20 -~

% M

0 M 2 % % 20 40

\

g 3 M O %

% %

0 M C

M 0 4 2 + % H % Ca 40 60

M

\

%

0 6 % %

60 80

% OW-200-O 0 8 % 80

Piper Diagram Diagram Piper

OW-408-D OW-408-D

OW-51 % 0 % 8 M M

Trilinear Diagram for Unconsolidat Trilinear

80 OW-409-D M

% % % %

0 0

6 % M 8

60

M

I l

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20 S 4 N

OW-43

OW-111-O OW-111-O

% % % %

0 0

2 I % 4 20

M

% %

0 2 % 40 -

Ca

M % 60 M M ~ 80% M M

60% %

80 Bicarbonate)

Groundwater

g M Unconsolidated

40% 20% Deposits (Calcium ‐ Native Support S EHS Figure 12 RD) in 111 ‐ ‐ other OW the Area 80, ‐ Completed to this OW

in R, Wells 20% J K K Plot

111 ‐ 4

O 40% ‐

S J

Compared % %

0 Groundwater 8 60% Bedrock J (OW

Bicarbonate) of Dike Bedrock Wells

‐

80%

Shifted K

K

% %

0 6 Wells

K Cl J J

Bedrock Clearly Diabase (Sodium Gneissic Majority Dike

K % 0

% 4

20 -~

%

0 2 % % 20 40 K

\

g 3 O %

% %

0 C

M K 0 4 2 + % H % Ca 40 60 K J K

K K

J K

Area)

OW-407-R OW-407-R % 0 OW-112-R OW-112-R 6 % % J

60 80 J

%

0 8 % OW-111-RD OW-111-RD 80 OW-401-RD OW-401-RD J OW-404-R OW-404-R Plume K K K J J OW-111-R OW-111-R OW-406-R OW-406-R OW-410-R OW-410-R J K

K J

OW-80

Piper Diagram Diagram Piper

K %

K 0 % 8 80 OW-33 K Northern OW-411-RD OW-411-RD OW-101-R OW-101-R

OW-401-R OW-401-R

OW-41

SMW-2 % % % %

0

OW-105-RD OW-105-RD 0 6 % K 8 60 J J K and

J

l SMW-3

% %

C

K %

0

0 +

K 6 4

4 %

% K +

K

O 0 a 20 S 4 N J OW-86

Groundwater

% %

Area % 0 0

2

0% 4 2 OW-407-RD

% %

0 2 0%

K 4 J Plume Trilinear Diagram for Bedrock Groundwater Samples Trilinear

- Bedrock OW-200-R OW-200-R Chloride)

K Ca OW-105-R OW-105-R Dip OW-200-RD OW-200-RD

‐ K the % of 60

~ J J J 80% Groundwater from K K K (Calcium ‐ Impacted (Down K K K J J K K 60% J %

80 K

g g K Away M J Bicarbonate) J Groundwater 40% Bedrock Degradation

20% Concentrations Chloride Direction Bedrock (Calcium ‐ Native Natural This the Chloride Produces in Native

from

Higher which

Shifted

impacted Resulting CVOCs Exhibit un ‐ Wells Support – Shallow Bedrock Well Well Shallow Bedrock – – Deep Bedrock Well Well Bedrock Deep – K J S EHS Figure 13

20%

O 4

!S 40%

% %

Groundwater 0 8 60% Bicarbonate) Dike ‐

80%

% %

Sulfate) 0 6 Water ~

!Cl

Diabase (Sodium

% %

0 % 4

20 - Surface (Calcium ‐

%

0 2 % %

20 40

\ 3

O

C

g

%

+

% %

M 3

0

! 0

4 2

+ % O %

a 0 C 0

C 4 H 6 ! !

Area)

%

0

6 % I %

60 80

%

0 8 0% , 8 Plume

Piper Diagram Diagram Piper

% %

0 % 8

80 Diagram Conceptual Trilinear Northern

% % % %

0 0

6 % 8

60

and

l

C

% %

! % %

0 0

+ K 6

4

4 % + 0%

O 0 a 2 S 4 ! !N

Groundwater

Area % % % %

0 0

2

% 4

I 20

% %

0 2 % 40 Plume

Bedrock - Chloride)

Dip !Ca ‐ % 60 ~ 80% (Calcium ‐ Impacted (Down Deposits

60% %

80

g g

M ! 40% 20% Groundwater Bicarbonate) Unconsolidated

Bedrock

Native & (Calcium ‐ Support S EHS -, ' ' .,, - --- ..__ ---- -...... / .,, / ' / .,, / ---- ' \ ' '- I /' ----- ' "' / / ------"\. '- / \ ;' -- " v,S Residence \ ,, ' ' ) t:\ / I / I II ""\ \ <;;oJ ( \ ' " \ \ \ "' ' --.. \~ /' I \ ) I/ - / ) ~ ------) / ---- / ------1so~" --- - - I ' ) ------~ OW-2O2-R ----- ~ ------Northern... Wetlands .,, --

... "' "' OW‐200‐O .... "' "' OW‐51 ...... ,. ... ( "' ...... "' "' ...... Western "' "' "' "' "' "' "' ,\ Fracture "' ;' ' ,.._ ,., .,. "' "' "' "' \ ,.i V Network Eastern Ponded Wetlands OW‐43 "' "' "' "' "' "' "' ;])"-\ "' "' "' "' "' "' "' "' "" .., "' -.,j,I" ~,\II "' "' ,.. + ... \ "' "' ... '*' "' ... ,.. ... \ "' " "' __ : --- OW‐409‐D "' ... "' ... ow ... ,, "' "' "' " OW‐408‐D ow 079 .., ... / "' "' "' "' "' "' "' ...... ------~ ------· " "' "' ~ '\ .., .., .., ,., ..., "' "' , ------~ .. ~ / - -- _,;f.£ _ "' ---- ______,., ... ·--::------~ ' "' "' "' Dike r -- ow 400 O "' "'· ~::::::=:=::::- \ OW‐111‐O Structure \ ,, I / Fracture / Dike StructureI '-.. Network <. I \. Dike Structure ~ - / ·------_.,.,--450 ___ '- -... ------' ,,------) SW- 701 C) Latham Brook I "' I r ,,,,-450'\ "" Eastern / I \ _.,, / "' Fracture / "' / I "' ---0§§..~ ow _925----· I ( °:! ) _ ----- "' Network \ ,. / / ow 024 '-- / " / ( / ___..:::.. / / --- I /

EHSS Support Stiff Diagrams for Surface Water Samples and Unconsolidated Deposits Groundwater Figure 14 -, ' ' - --- ..__ --- -...... / .,, / ' / / ---- / .,­ ' \ ' '- / ------' "' / / / ;' ----- "\. '- / \ -- " v,S Residence \ I ,, ' ' ) t:\ / / I \ \ I <;;oJ II ( \ " ' \ \ \ ' --.. \~ / / I I/ "' "\ ) - --- / ) ~ - -- - ) / ---- / ------1so~" ------I ' ) ow OW-2O2-R------~ --- OW‐404‐R

OW‐101‐R OW‐406‐R OW‐112‐R OW‐200‐R

Western OW‐407‐R Fracture Network

OW‐41 "" ""- ---...... -- "' "' ow- 1::....---;-r=i:7;:;;==.:~ .., ow OW‐33 0W-01 1 "" "" ·"' ... ,, "' "' "' " ow 079 .., ~(\: o~ SMW‐2 "' "' "" "' "' .., .., .., ~ /.,, " "" -"' .., "" , / OW‐111‐~R "' . _; ~~ ..:.... - ~-_ ------~ --- , _,;f.£ _ ------~ : 0 Dike ,,- - ow 400 O ,,,,..:-~___:,,_--_---....:-_ OW-110-R Structure \ I / + ow-021 Fracture Dike StructureI '-- Network I OW‐80 \. Dike Structure / . ------'- .,.,,,..-4s- 0 ____ - --­ OW‐105‐R ------1.0 0.5 0.0 0.5 1.0 ------Mg SO4 ---- ..- ----) Ca HCO3 C) + K Cl I I OW‐86 r .,,.,,-450'\ Eastern / \ ,,...... - / (\-~~ l: Fracture / I ow 0§§.. ) C?w.-w-s-~ ., Network I ( \ -~ "' / '--. / / ow 024 " ~ ( / / / --- I /

EHSS Support Stiff Diagrams for Shallow Bedrock Groundwater Figure 15 -, ' ' - --- ..__ ---- -...... / .,, / ' / ---- ' \ ' '- I ------' "' / ------"\. / \ -- v,S Residence \ I ,, ' ' ) t:\ / / \ \ I <;;oJ ( \ " ' \ \ ' \~ / \ ) "\ " - --- / ) ~ - -- - ) / ------1so~" --- - - I ' ) OW-202-R------~ --- ...... "' "' "' "' "' "' "' "' -i, ... "' "' "' OW‐407‐RD OW‐200‐RD "' "' "' "' "' "' "' ... \ w "' "' "' "' ... "' "' "' Western ...... "' ' "' "' "' "' Fracture "' "' / ' ,.._ "' "' "' "' Network "' "' "' "' "' "' OW‐401‐RD "' "' "' "' "' "' "' "' "' "' "' I ,i, ,j, 'IV' "" "' \ "' "" "' ...... "' "' "'\ "' 'r"' "' OW‐401‐R OW‐410‐R --- "' ..., ...... ,, ow 079 "' "' "' "' ... ,...... / OW‐411‐RD "' "' "' "' .,, ~ ...... -i, ... ',y ~ "' "' "' ... iP ' / "' "' "' ... "' "' ...... sv· ... ·------"' \, .... Dike "' Structure l I ,,- OW 107 0 Fracture Dike StructureI OW‐111‐RD ---- Network I ,,- \. Dike Structure ~ .,, / ·------....----4s0 ___ -­ '- OW‐105‐RD SMW‐3 ------) I r .,,.,,-450'\ Eastern / \ / ... Fracture / / I "' °:!---0§§..~ ow_ _925 - I ( ) ------"' Network \ ,. / / ow 024 '-- ./ " / ( / "' / / --- I /

EHSS Support Stiff Diagrams for Deep Bedrock Groundwater Figure 16 0

-10 .... ,,, ,,, .... OW‐111‐R OW‐86 SMW‐3 OW‐112‐R 20 EPW Bedrock Wells Exhibiting OW‐200‐R Native, Unimpacted OW‐407‐RD Geochemical Type 30 OW‐80 OW‐407‐R NW OW‐410‐R ~ 0 Latham Brook

~ OW‐105‐R V') OW‐406‐R OW‐105‐RD OW‐409‐D OW‐93‐O > SMW‐2 OW‐101‐R - OW‐33 "? -50 OW‐408‐D E OW‐411‐RD OW‐43 OW‐401‐RD OW‐51 ::::s OW‐200‐O OW‐41 ·-I,,,. OW‐404‐R cu OW‐111‐O .., y = 6.0016x- 1.6752 OW‐200‐RD -60 OW‐111‐RD OW‐112‐O ::::s 2 ,,, R = 0.9628 ....OW ‐401‐R cu --r,..e ,,, .. C ...1,a'te~ \) ... .,. . c.,'11 :; .,eof..")..... -70 ~~e~... \,Q.c.,'9;.. ..

-80

-90

-100 -12 -11 -10 -9 -8 0 -7 -6 -5 -4 -3 -2 -1 xygen-18 (VSMOW}

EHSS Support Stable Isotopes O vs 3H Figure 17 0

,,. .. -10

...,,,. OW‐111‐R OW‐86 .. ,,,.Winter> 2015 SMW‐3 OW‐112‐R Shallow Flow System Groundwater Surface Water 20 EPW Estimated Based on End Member OW‐200‐R Site Data and URI Data OW‐407‐RD [d18O value of ‐7.3‰]

30 OW‐80 OW‐407‐R Shallow Flow NW OW‐410‐R -s System Groundwater 0 Latham Brook

~ OW‐105‐R V') OW‐406‐R OW‐105‐RD OW‐409‐D OW‐93‐O > SMW‐2 OW‐101‐R OW‐33 M -I -50 OW‐408‐D E OW‐411‐RD OW‐43 OW‐401‐RD OW‐51 ::::s OW‐200‐O OW‐41 ·-I,,,. OW‐404‐R ..,cu OW‐111‐O OW‐200‐RD OW‐111‐RD OW‐112‐O ::::s -60 cu OW‐401‐R C

Regional Flow System Groundwater

The Stable Isotope Results are Variable for each of the Regional Flow Well Types (Overburden, Shallow Bedrock, Deep Bedrock). System Groundwater This variability is Evidenced by the Locations of the Isotopic -90 Estimated Based on Results Along the Local Meteoric Water Line and Supports that Ferguson and Jasechko (2015) Groundwater Flow and Mixing are Highly Variable at the Site [d18O value of ‐12‰]

-100 -12 -11 -10 -9 -8 0 -7 -6 -5 -4 -3 -2 -1 xygen-18 (VSMOW}

EHSS Support Interpretative Stable Isotopes O vs 3H Figure 18 0

...... , .. -10 ,, ,, ., ..., .,, ., .. ., .,, D -20 D

-30 URI Groundwater Data from -s Pawcatuck River Watershed 0 -40 ~ V') > URI Surface Water Data from Pawcatuck River Watershed -'°? -50 E :::s ·-~ Q1 ; -60 Q1 C

-70

-80

-90

-100 -11 -10 -9 -8 0 -7 -6 -5 -4 -3 -2 -1 xygen-18 (VSMOW}

EHSS Support Stable Isotopes O vs 3H with Data from URI Figure 19 ...... ------...... --- ...... z ------' '',' ...... _ ------...... '-- ...... __ --:__,:.:--<,, ...... ------...... _---- t ...... ------LEGEND: /-----, // - // ---- ...... - ...... '-- ' \ ' \ ' ,.... --- -...... _ ' ,....----, ' ( \ ------' ___ ------"- ', \ ',-.... To Davis Residence /"/ --- ,, \ ' ,_ I / / / ------,,...___ -' " ' ..,_'- ,_ -, ) _/ I ( '\ ' ,__ \ 0W-200-R ', '\ \ ,_ - ..... I I I' ,,..-- __ _, ', \ " " ------BEDROCK Copyright © ESS Group, Inc., 2016 © ESS Group, Inc., Copyright I -..... ' \ -- ...... ' /- 45Q.J '-, \ / I I I/ ("--, ' \ -...... ,_ --- ,, -__ ,,, ~ / ___..,, - ', ' / I ( ,,'-._') , _ _. \ - '--. MONITORING WELL I /_.... / - '- ,, ------~ -,, '- / ---- ) / / I \ ----- OW-200-RD• -- ' ' ) \ I I / r I/ --- -.... J ', I ------( ( --..., / -- '..,_ ',J ~--- BEDROCK SENTRY WELLS 1 '-- ,....,.... / ,,,,,,..--- -E,t- ,....---- -450------/) ' __ ) I '-- ' / ' ..._____ ~ / / / __-_-_-_-_--:_-_:- __/,, / \ \ __,.,. 1 ---- // ( - J \ / __ / / .....___ ROADS (PAVED) , ______( ' ROADS (UNPAVED) -;------~ ~-- 7 ------/ ...__.,., ,,,,,,,.----­' _....----- ~ ---,,....-I ~ ' -- -- ,....--- __ , _ ------­ DELINEATED WETLAND AREAS ' ...... _ ____ ..,..------. ' _ --- . (DASHED WHERE APPROXIMATE) --- .... D ,..--' I' . POND (APPROXIMATE) / / I D / / ' , ___ APPROXIMATE LIMIT OF SATURATED / ' UNEXCAVATED SOIL I (FORMER SOURCE AREA) \

' ...... APPROXIMATE LOCATION OF ' ...... "' ...... DIKE STRUCTURE .., .., .., ...... 18 d O RESULTS: ...... -8.43 SHALLOW BEDROCK WELLS DEEP BEDROCK WELLS 0 ' -8.35 OCJ ' '

0 N

NOTES: 1. BASE PLAN HAS BEEN COMPILED FROM SITE SURVEYS CONDUCTED BY MARK N. NYBERG ASSOCIATES, INC. (DECEMBER 2001; MAY 2003, REVISED AUGUST 2003 AND DECEMBER 2003; AND OCTOBER 2008), SITE SURVEYS CONDUCTED BY DIPRETE ENGINEERING (NOVEMBER 2012, C .Q OCTOBER 2013 AND APRIL 2015), AND c :, -8.S WOODWARD-CLYDE FINAL PRE-DESIGN " ENGINEERING REPORT II (OCTOBER 1993). t.:i I I I 2. ** REPLACEMENT WELLS INSTALLED IN THE I I GENERAL LOCATION OF WELLS DECOMMISSIONED DURING SOURCE / ' REMEDIATION.

I 3. DIKE STRUCTURE LOCATION BASED ON APPROXIMATE INTERPRETED LOCATION OF ,..../ ,....,.,.,.,. DIORITE DIKE (BASED ON GEOPHYSICS) (SOURCE: WOODWARD-CLYDE CONSULTANTS, / I' ,,.... --- FIGURE G-2, DATED: 11/23/1992), APPROXIMATE / / LOCATION OF DIORITE DIKE ____-- ..,,,,,,. I (SOURCE: CAMP DRESSER & MCKEE, INC., -- / / FIGURE 4-1, DATED: JANUARY 1986) AND / FINDINGS DURING HISTORIC AND RECENT DRILLING ACTIVITIES.

Davis Liquid Waste Superfund Site Plan View of d18O Results Smithfield, Rhode Island Project No. D164-007 Scale: 1"=300'

en1Jironmen al insulting 0 300 FEET & engineering services Figure 20 ...... ------...... --- ...... z ------' '',' ...... _ ------...... '-- ...... __ --:__,:.:--<,, ...... ------...... _---- t ...... ------LEGEND: /-----, // - // ---- ...... - ...... '-- ' \ ' \ ' ,.... --- -...... _ ' ,....----, ' ( \ ------' ___ ------"- ', \ ',-.... To Davis Residence /"/ --- ,, \ ' ,_ I / / / ------,,...___ -' " ' ..,_-...... ,_ -, ) _/ I ( '\ ' ,__ \ 0W-200-R ', '\ \ ,_ - ..... I I t' ,,..-- __ _, ', \ " " ------BEDROCK Copyright © ESS Group, Inc., 2016 © ESS Group, Inc., Copyright \ ...... I 45Q.J '-, -..... \ ' -- ' / /- ..,, / I I I/ ("--, ' \ -...... ,_ ~ --- ,, -__ ,,, ~ ___ - ', ' / I ( ,,'-._') , _ _. \ - "- MONITORING WELL I /_.... / - '- '- ,, ------~ ) -,, / ---- ' ' / / I/ I \ '....,_ ----- OW-200-RD ------) \ I I ( ( --..., / -- '..,_ ',J / r ~------.... J I 1 '-- ,....,.... / ,,,,,,..--- -E,t- BEDROCK SENTRY WELLS ,....---- -450------/) ' __ ) I '-- ' / ' ..._____ ~ / / / __-_-_-_-_--:_-_:- __/,, / \ \ 1 ---- // ( - J \ / __ / / -...... _ ROADS (PAVED) , ______( ---- ' -;------~ ~-- 7 --- ROADS (UNPAVED) ...__.,., ,,,,,,,.----­' ------_.... I ' -- -- /,....------~ ------, ~___ ------­ DELINEATED WETLAND AREAS ' ...... _ ____ ..,..------. ' _ --- (DASHED WHERE APPROXIMATE) --- .... D ,..--' t' . POND (APPROXIMATE) / I / D / / ' , ___ APPROXIMATE LIMIT OF SATURATED / ' UNEXCAVATED SOIL I \ (FORMER SOURCE AREA)

' ...... ' ...... "' APPROXIMATE LOCATION OF ...... DIKE STRUCTURE .., .., .., ...... 3 ...... d H RESULTS: r') ...... I .. E -51.7 SHALLOW BEDROCK WELLS .:!

2:, ' ...... DEEP BEDROCK WELLS Q) ' -50.2 0

N

NOTES: 1. BASE PLAN HAS BEEN COMPILED FROM SITE SURVEYS CONDUCTED BY MARK N. NYBERG ASSOCIATES, INC. (DECEMBER 2001; MAY 2003, REVISED AUGUST 2003 AND DECEMBER 2003; AND OCTOBER 2008), SITE SURVEYS CONDUCTED BY DIPRETE ENGINEERING (NOVEMBER 2012, OCTOBER 2013 AND APRIL 2015), AND WOODWARD-CLYDE FINAL PRE-DESIGN ENGINEERING REPORT II (OCTOBER 1993). I I 2. ** REPLACEMENT WELLS INSTALLED IN THE I GENERAL LOCATION OF WELLS DECOMMISSIONED DURING SOURCE ' REMEDIATION.

I 3. DIKE STRUCTURE LOCATION BASED ON / APPROXIMATE INTERPRETED LOCATION OF ,.... DIORITE DIKE (BASED ON GEOPHYSICS) ,....---- (SOURCE: WOODWARD-CLYDE CONSULTANTS, / /' ,,.... --- FIGURE G-2, DATED: 11/23/1992), APPROXIMATE / / LOCATION OF DIORITE DIKE ____-- ..,,,,,,. I (SOURCE: CAMP DRESSER & MCKEE, INC., -- / / FIGURE 4-1, DATED: JANUARY 1986) AND / FINDINGS DURING HISTORIC AND RECENT DRILLING ACTIVITIES.

Davis Liquid Waste Superfund Site Plan View of d3H Results Smithfield, Rhode Island Project No. D164-007 Scale: 1"=300'

en1Jironmen al insulting 0 300 FEET & engineering services Figure 21 Figure 22 ""· 20%

4

SO 40%

% %

0 8 60% 2.1 9.3 6.1 -76.8 -76.8 -82.7 -87.7 .0 1

80%

% %

0 6 Potential (milliVolts) Potential (milliVolts) Oxidation Reduction Charge Balance (%) J Cl

J J

% %

0

% 4

20

%

0 2 % % 20 40

31 76 23

5.2

3 3 6.24

g 5.98 % O

% %

0 0

M C 4 2 + % H %

a 40 0

C 6 0.0

% Sulfate (mg/L) 0 6 % % 60 80

pH (Standard Units)

%

0 8 % 80 Northern Wetlands Eastern Ponded Wetlands Eastern J J J

Piper Diagram Diagram Piper

% % Wetlands 0 8 11

5.5 % 7.3 169 237 80 123

Specific

% %

% % 0 0 0

6 % 8 1. 0 (umohs/cm)

6 Conductance

Chloride (mg/L) Chloride

l

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20

S 4 N

% % %

0 0

2 0% 4

Latham Brook 2

Northern

% %

0 2 -- - % - 40 K ca + Mg Na 9.4 8.87 2.93 12.2 10.42 19.52 Ca

%

0 (Degrees C) 6 Temperature J carbonate (mg/L) - J Bi 80% 80%

60% 60% %

80

g g J M 40% 40% 20% 20% 7.5 6.1 4.7 -35 -35 -41.4 -41.4 -22.4 (VSMOW) (VSMOW) Deuterium-3 Sodium (mg/L)

2.9 2.4 2.3 -3.2 -6.84 -5.94 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 Magnesium (mg/L) (mg/L) 2 18 14 2.0 4.6 1.8 3.3 Summary of Surface Water Data Summary of Surface Water Potassium (mg/L) Silica as SiO as Silica Brook

~ - 14 29 1.0 9.4 Ol'Hll/ 0.26 0.34 006 '- ,', 0' ~ ,:1 - Calcium (mg/L) Calcium Latham 0, Manganese (mg/L) 41 )CB OW ----·-·--r-·---- l - C 3.7 1.1 0.17 .0 1 Iron (mg/L) Water Type Type Water Wetlands Calcium-Sulfate Calcium-Sulfate Calcium-Sulfate

fJ/<)25 - 4 02 ' ':/i, ~ 8WJl!5 ~ ------Northern Depth Depth Depth Depth Brook

\ ,) 4 Wetlands Latham Surface Water Surface Water Surface Water Surface Water Surface Water Surface Water Sample Location Sample Location .0 1 Ponded

Residence , is v /, Da - - -- .5 1 '., , :1 K To ca Mg + t ~, ______Eastern _ __ V -! , c+-J[i Well Well Wetlands \\ - Latham Brook Latham Brook Northern Wetlands Northern Wetlands ------~---i----- ~------Eastern Ponded Wetlands Eastern Ponded Wetlands - Support Ponded

S Eastern EHS Figure 23 20% 4.2 8.4 -0.2 -0.5 21.3 -79.7 -73.8 -74.3 -44.2 -113.1

4

SO 40%

% %

0 8 Potential (milliVolts) Potential (milliVolts) 60% Oxidation Reduction Charge Balance (%)

80%

K

K

% %

0 6 Cl 14 12 17

7.8 ND

6.18 6.24 5.78 6.55 5.73

% %

0 % 4 20 --

ulfate (mg/L)

% S

0 M 2 % % R 20 40 K ‐

pH (Standard Units)

g 3 % O

% %

0 0

M C 4 2 + % H % Ca 40 60

404

%

0

6 ‐ % %

60 80

%

0 8 % 80 51 28 89 55 OW 6.0 3.9 ‐ 375 104 330 580 2316 K Specific (umohs/cm) R Conductance K

‐ Chloride (mg/L) Chloride OW

Piper Diagram Diagram Piper

% %

0 % 8

80 M

% %

406 % 0 0

6 % K 8 60 ‐ R

‐

l

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20 S 4 N

OW

% % %

0 0

2 % 101 4

20 ‐ 12.43 13.67 14.72 14.26 12.54 146.4 50.02 32.94 15.86 561.2

% %

0 2 %

0 (Degrees C) 4 Temperature OW - Bicarbonate (mg/L) Ca K

%

60

M

- R ‐ 406 ‐ OW 80% 80% K K 20 23 60% 60% 5.2 % 2.8

80 150 -49.6 -49.6 -50.1 -50.8 -50.8 -48.3 -47.6 -47.6

g g M (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20%

22 3.7 1.6 1.5 -8.1 -7.6 0.83 -8.16 -7.94 -7.14 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 Magnesium (mg/L) From Former Source Area Source From Former L) (mg/L) 2 ---,-;-~ 17 15 24 34 17 18 4.5 5.0 1.2 1.9 Potassium (mg/ Silica as SiO as Silica R \J/ \V ‐ 5" R 4 ‐ w ------\V \V \V

0

25 43 16 2.8 1.9 3.6 5.1 8.2

M9

300

0.65 406 R ‐ 101 ‐ OW

51 ‐ ‐ OW \J/ \JI \V \V 101 W.-- ‐ --- Calcium (mg/L) Calcium \J/ \V \V Manganese (mg/L) OW - OW ~ \JI ~ \V 04 \J/ \V - -- ~ \V "' Summary of Groundwater Data o \J/ 26 3.2 9.0 7.2 5.7 51 ‐ UNS-1 \J/ \V Iron (mg/L) Iron Water Type Type Water w \V Calcium-Chloride Calcium-Chloride OW Calcium-Bicarbonate Calcium/Iron-Bicarbonate Calcium/Iron-Bicarbonate w w 5-27.5 -18.5 38-48 38-48 Depth Depth Depth Depth 1 1-18.5 1-18.5 \V \V \V \V \V \V 83.2-93.2 83.2-93.2 17. 17.5-27.5 44.75-49.75 44.75-49.75

O Bedrock Bedrock Bedrock Bedrock Bedrock Bedrock R ‐ 404 ‐ OW

Sample Location Sample Location 93 ‐ ‐ Unconsolidated Deposits Unconsolidated Deposits Unconsolidated Deposits Unconsolidated Deposits OW Well Well R OW-51 OW-51 ‐ OW-93-O OW-93-O OW-406-R OW-404-R OW-101-R OW-404-R OW-101-R OW-406-R 404 rt ‐ po OW p ) ~ Su S S H E Figure 24 4 Cl 50 0 1 37 -6.3 -5.1 -1.1 -167 -225.1 20% J

4

O 40%

S J

% % Potential (milliVolts) 0 Oxidation Reduction Charge Balance (%) 8 60% J

80%

% %

0 6 Cl 4.3 3.7

0.86 7.09 7.58 6.79

% % ulfate (mg/L) 0

% 4

0 -- 2 S

%

0 pH (Standard Units) 2 % %

20 40

------

g 3 % O

% %

0 0

M C 4 2

+ % H %

Ca 40 60

%

0 6 % %

60 80

% 98 0 8 350 % 145 1168 4694 80 1700 Specific OW-411-RD OW-411-RD OW-401-RD OW-401-RD (umohs/cm) Conductance J J Chloride (mg/L) Chloride J OW-401-R OW-401-R

Piper Diagram Diagram Piper

% %

0 % 8

80

% % % %

0 0

6 % 8 60

RD

l ‐

% %

C % %

0

0 +

K 6 4

4 % + %

O 0 a 20 S 4 N

14.18 12.94 13.25 56.12 219.6 % %

% % 112.24 0 0

2 % 4 20 411

‐

(Degrees C) Temperature

% %

0 0 -- 2 % 1 40 Bicarbonate (mg/L) Ci - OW Ca

% 60 - 80% 80% 48 15 -55 -55 140 J -63.6 -63.6 -54.3 l C SO~ 60% 60%

J 0%

8 (VSMOW)

g g Deuterium-3 M - Sodium (mg/L) J 40% 40% 20% 20%

10 34 7.2 -9.65 -8.95 -8.87 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 Magnesium (mg/L) From Down-Dip Plume Area From Down-Dip Plume L) (mg/L) ------2 26 15 15 5.7 4.4 4.6 Potassium (mg/ Silica as SiO as Silica ,r 10 ( \ - ---- 46 1.2 4.5 150 720 OW 0.60 RD ....._ ‐ __ Calcium (mg/L) Calcium Manganese (mg/L) 401 ‐ ------K W __ Ci + O ...._ Summary of Groundwater Data 11 0.22 0.23 um-Chloride um-Chloride Iron (mg/L) Iron Water Type Type Water 00~ 5(J Calcium-Chloride Calcium-Chloride Calcium-Chloride Calcium-Chloride Calci «I RD ‐ JO 401 Depth Depth Depth Depth 367-387 235-245 367-387 235-245 ‐ 137.6-147.6 137.6-147.6 137.6-147.6 137.6-147.6 XI OW 0 1 k ------\j. Bedrock Bedrock Bedroc 'V Deep Bedrock Deep Bedrock Deep Bedrock Deep Bedrock Sample Location Sample Location 'IV RD ‐ 'V R ‐ \ 'IV 411 _,.,.. ‐ R 401 'V \jr- ‐ ‐ _,.,.. OW - 'V 401 Well Well OW ‐ -- ~ 'IV OW-401-R OW-401-R OW-401-R OW-401-R /4' OW-411-RD OW-401-RD OW-411-RD OW-401-RD --- - ca OW 'IV 'V 'V - ,, 'V 'V 'V ------'IV 'V 'V 'V 'V / - 'IV 'V 'V ---- / Support '- -- v 'IV 'V 'V / -... -----;-,- S EHS Figure 25 20% 2.1 0.1 -0.9 -2.7 -0.8 -93.8 -99.5 -98.6 -27.7 K 158.9 K -100.9 -190.8

4

SO 40%

% %

0 8 Potential (milliVolts) Potential (milliVolts) 60% Oxidation Reduction Charge Balance (%)

80%

% %

0 6 R K ‐ Cl R 12 17 15 20

5.5 4.2 6.4

‐ 6.77 7.95 6.81 8.25 7.95

% %

0 407 % 4 20 -- ‐

ulfate (mg/L)

% S 0 112 2 % % 20 40 ‐

pH (Standard Units)

3 3 M

OW g % O

% %

0 0

M C 4 2 + % H % Ca 40 60

OW

%

0 6 % % R ‐ 407 ‐ OW

60 80 J

%

0 8 % 80 46 18 4.4 2.2 K 678 282 158 110 450 460 K 1355 1551 41 RD Specific ‐ ‐ (umohs/cm) Conductance

Chloride (mg/L) Chloride

43 Piper Diagram Diagram Piper

K %

‐ 0 % 8 0 OW

8 407

‐

% % % %

0 0

6 % 8 60 OW M

J l

% %

C % %

0

0 +

K 6 4 OW

4 % + %

O 0 a 20

S 4 N

% % %

0

0 13 61 2 0% 4 2 11.9

12.67 13.37 11.97 13.24 158.6 34.16 58.56 86.62

119.56

% %

0 2 % 0 (Degrees C) 4 Temperature - Bicarbonate (mg/L) Ca

% 60 - J 80% 80% K M K K 31 12 68 13 77 60% 60% 3.3 -54 -54

0% -52

-50.3 -50.3 -53.3 -53.3 -50.2 -50.2 8 -53.4

g g M (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20%

4.9 2.5 6.6 6.6 0.62 0.47 -8.02 -8.65 -7.89 -8.71 -8.41 -8.69

(VSMOW) (VSMOW) Oxygen-18 Oxygen-18

RD ‐ 407 ‐ OW Magnesium (mg/L) L) (mg/L) ------~ 2 26 21 12 13 6.0 8.7 8.4 1.9 4.6 7.4 8.2 0.65 :o,---t-= Potassium (mg/ Silica as SiO as Silica --- '-.. \j/ 74 33 19 --- 4.1 1.9 4.4 3.5 1.4 190 200 \j,-, \j/ 0.034 0.0059 ------~

)

--- I

\j/

Calcium (mg/L) Calcium 43 ‐ OW Manganese (mg/L) ,,.,,,-- --- \j/ , '-- ...L \)I ) " ...... \j/ \V ( ~ Summary of Groundwater Data From Northern Plume Area Plume Data From Northern Summary of Groundwater \j/ \j/ R ‐ O ------‐ 5.6 5.9 ND 0.23 -Bicarbonate -Bicarbonate \)I 0.069 0.029 407 Iron (mg/L) Iron Water Type Type Water ‐ \j/ 112 "' ‐ Calcium-Chloride Calcium-Chloride Calcium-Chloride Calcium-Bicarbonate Calcium \V

OW

Calcium/Sodium-Bicarbonate OW

\j/ \)I

R ‐ 112 ‐ OW \V -14 \j/ 5-162.5 5-162.5 5-162.5 5-162.5 \)I 4 4-14 4-14 55-65 55-65 19-24 19-24 Depth Depth Depth Depth 32.5-77 32.5-77 / 81.5-91.5 81.5-91.5 \j, \)I 152. 152. RD \V 'V ‐ 036 41 ‐ \V - 407 ‐ \j/ \)I OW OW edrock edrock \V OW R Bedrock Bedrock Bedrock Bedrock Bedrock Bedrock ‐ \j/ \j/ \V Deep B Deep Bedrock Deep Bedrock Sample Location Sample Location \j/ \)I 'V \V 112 ‐ Unconsolidated Deposits Unconsolidated Deposits Unconsolidated Deposits Unconsolidated Deposits \j/ \j/ \jl \jl \V \V OW \j/ \)I \)I \)I \)I CW-2 \V 43 \j/ \j/ 'V \V \V 'V 'V ‐ ~ \j/ \V \V \V w OW Well Well \)I \)I \)I \V OW-41 OW-41 OW-43 OW-43 5> OW-112-R OW-112-R OW-407-R OW-407-R OW-112-O OW-112-O 4 OW-407-RD OW-407-RD OW-407-RD OW-407-RD \)I \)I \)I .. 0 rt \j/ \V \V 'V

~

\)I \)I

41 ‐ OW

$) ~ \V \V 'V 4 Suppo S S H E Figure 26 20% 0.4 8.8 1.3 -0.2 -3.5 40.1 -18.1 -21.3 -20.6 -20.2 -20.2 115.3 -160.8

4

SO 40%

% %

0 8 Potential (milliVolts) Potential (milliVolts) 60% Oxidation Reduction Charge Balance (%)

80%

% %

0 6

Cl RD ‐ 111 ‐ J OW

12 20 12

9.5 5.4 9.5 8.8 9.1

5.72 7.15 9.27 9.59

% %

0 % 4 20 -- ulfate (mg/L)

RD

% S 0 2 ‐ % % 20 40

pH (Standard Units)

g 3 % O

% %

0 M 0

M C K 4 2 + % H % Ca 40 60 111 R

K ‐ J

% ‐

0

6 % %

60 80

%

0 8 0% OW 111 8 J 24 98 ‐ 3.2 4.3 3.5 3.5 5.8 134 173 159 213 285 Specific (umohs/cm) Conductance OW K O Chloride (mg/L) Chloride

Piper Diagram Diagram Piper

‐

% %

0 % 8

80

% % % %

0 0

6 % M 8

60 111

J ‐

l

% %

C

K %

0

0 +

K 6 4

4 % + %

O 0 a 20 S 4 N R

‐

RD

% % %

0 OW 0

2

0% ‐ 4

2 42.7 82.96 51.24 39.04 59.78 53.68 15.49 11.78 12.82 11.92 12.39 11.31

% %

0 105 2 %

0 (Degrees C) Temperature

K 4 J ‐ 105 ‐ - Bicarbonate (mg/L) Ca OW % OW 60 M - J 80% 80%

K

11 13 27 16 60% 60% 80 ‐ OW 4.1 4.4 %

80 -59.3 -59.3 -52.4 -47.8 -47.8 -52.7 -52.7 -54.6 -54.6 -50.2

g g M (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20%

1.5 3.6 -8.6 0.79 0.44 0.74 0.39 -9.42 -8.15 -8.59 -8.81 -8.35 -8.35 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 Magnesium (mg/L) L) (mg/L) 2 13 20 21 22 21 31 2.5 2.6 2.0 1.5 3.2 2.6 Potassium (mg/ Silica as SiO as Silica Summary of Groundwater Data From Dike Area Data From Dike Summary of Groundwater R - \ 0 - 1 0

21 15 10 11

9.1 8.3 ND ~

0.019

02 0.0016 0.0041 0.0018 0.0016

R ‐ 111 ‐ OW

41 - O ‐ 111 ‐ OW ,- - - Calcium (mg/L) Calcium w 0W Manganese (mg/L) W --- • ~ R ‐ 80 111 ‐ ‐ ND ND 0.21 0.022 0.029 0.096 ( OW Iron (mg/L) Iron OW ow Water Type Type Water \ /Calcium-Bicarbonate Sodium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate odium-Chloride/Bicarbonate odium-Chloride/Bicarbonate Sodium Calcium/Sodium-Bicarbonate S 215 ---- -15 1 I 5 5-15 5-15 39-49 78-93 39-49 78-93 Depth Depth Depth Depth 223-238 223-238 200- 223-238 200-215 O 19.5-29.5 19.5-29.5 ‐ "------11 '6) - - RD ) 1 ‐ ~ 111 1; RD ‐ \ ‐ 1 o 105 ‐ W- _

OW 111

‐

Q --..... 105= -

RD ‐ 105 ‐ OW ~ OW '--- Bedrock Bedrock Bedrock Bedrock Bedrock Bedrock o r-...... _ OW w..:. \ ( , Deep Bedrock Deep Bedrock Deep Bedrock Deep Bedrock Deep Bedrock Sample Location Sample Location :o --..... -- 3 0 Unconsolidated Deposits Unconsolidated Deposits 4 ---- - SO HCO Cl / 1.0 1.0 f ------..... ~ ---- r - \.. ~ ( 105 ~ ...... - \ ~ ) - ...::.._ \ ~ R 0.5 - \ ‐ 0W \ Well Well , --- OW-80 OW-80 105 OW-105-R OW-111-R OW-111-R OW-105-R OW-111-O OW-111-O ‐ OW-111-RD OW-111-RD OW-105-RD OW-111-RD OW-105-RD -...... 0.0 -- OW ---...... ------7~--- ___, 0.5 0.5 Support S

1.0 Ca Mg + K R ‐ 105 ‐ OW

EHS Figure 27 20% -0.8 -3.5 -2.5 -6.6 62.3 -39.9 -54.9 -61.1

4

SO 40%

% %

0 8 60% Potential (milliVolts) Potential (milliVolts) Oxidation Reduction Charge Balance (%)

80%

% %

0 6 Cl J M 11 8.1 8.3 6.8

7.26 8.59 6.06 5.85

% % R K 0 % 4 -- 20 ‐

ulfate (mg/L)

% M

0 S 2 % % 20 40 410

pH (Standard Units)

g 3 % O

% % ‐

0 0 M C

R

4 2

a + 0% H %

C ‐ 4 60

%

0 6 % % 60 80 OW

410

% ‐ 0 8 % 80 32 23 10 29 192 205 230 125 D Specific ‐ OW (umohs/cm) D Conductance ‐ J

Chloride (mg/L) Chloride

Piper Diagram Diagram Piper

% %

0 % 8 M

80 408 M

K ‐

% %

409 %

0 0

6 % 8 33

60 ‐

‐

l

% %

C % %

OW 0

0 +

K 6 4

4 % + %

O 0 a 20 S 4 N

OW

% %

OW %

0 0

2 % 4

20 54.9 42.7

58.56 10.92 12.46 11.81 12.16 63.44

% %

0 2 0% 4 (Degrees C) Temperature - Bicarbonate (mg/L) Ca

M % 60 J - 80% 80% K M 60% 60%

% 14 7.7 5.9 7.4

80 -50

-51.7 -51.7 -54.1 -48.9 -48.9 g g M ta From Central Area ta From Central (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20%

1.0 1.9 1.5 2.2 -8.7 -8.43 -7.97 -7.91 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 33 ‐ Magnesium (mg/L) OW L) (mg/L) 2 13 15 11 13 3.9 4.3 4.9 3.8 l HOO: C - -' ' Potassium (mg/ Silica as SiO as Silica Summary of Groundwater Da --- - "- ---- OW 23 21 23 1.6 9.0 0.21 0.68 0.049 r- ) I o -' ' Calcium (mg/L) Calcium 011 1 Manganese (mg/L) ,,,,,,.-- - - + 0W ow '-' ~ R ‐ -' ' 5.0 ND 0.15 0.079 410 Iron (mg/L) Iron Water Type Type Water ‐ D Calcium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate ‐ cium-Chloride/Bicarbonate OW -- Calcium/Sodium-Bicarbonate Cal 409 33 ‐ ‐ ------' ------~~------' K ~ + Nai OW 8-13 8-13 8-13 8-13 OW 16-58 14-19 16-58 14-19 Depth Depth Depth Depth 172-187 172-187 S D - - its 37 036 - 408 - 408 HCO: Cl SO.. W - - 0W OW OW ~ Bedrock Bedrock ~ Deep Bedrock Deep Bedrock Sample Location Sample Location 03 ----- D ‐ Unconsolidated Deposits Unconsolidated Depos Unconsolidated Deposits Unconsolidated Deposits -v D 409 ‐ ------‐ ------408 OW ‐ OW Well Well OW-33 OW-33 OW-410-R OW-410-R OW-408-D OW-409-D OW-408-D OW-409-D / D / ‐ ---- / 408 / ‐ ------Mg OW Figure 28 3 20% 1.1 -1.8 -1.1 29.7 235.3

4

O 40%

S M

% %

0 8 60% Potential (milliVolts) Potential (milliVolts) Oxidation Reduction Charge Balance (%)

80%

% %

0 6 Cl

8.0 8.8 8.2

7.25 8.01 4.98 O

% %

0 ‐ % 4 20 --

ulfate (mg/L)

%

0 S 2 % % 20 40

200

pH (Standard Units)

3 3

g ‐ % O

% %

0 0

M C 4 2 + % H % Ca 40 60

M

K %

0

6 0% 0% J OW 6 8

%

0 8 % 80 32 2.8 4.1 141 134 120 R ‐ Specific (umohs/cm) Conductance

--=--=-~=-=~--=--=--=-----;

Chloride (mg/L) Chloride

Piper Diagram Diagram Piper

% %

200 0

0% 8 8 ‐

% % % %

0 0 ___L__

6 % 8 60

OW

l

% %

C % %

0

0 +

K 6 4

4 %

% K +

O 0 a 20 S 4

N __ J

% % %

0 0

2 0% 4

2 RD RD 13.33 10.72 5.612 90.28 12.68 80.52

‐ ‐

M % %

0 2 0% 4 (Degrees C) Temperature - 200 200 Bicarbonate (mg/L) ‐ ‐ Ca

% 60 W - OW O 80% 80% 60% 60% % 17 5.6

80 6.1 K

-51.6 -51.6 -53.2 -56.6

g g M J (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20%

1.0 0.50 0.56 -8.51 -8.51 -8.36 -9.04 -9.04 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 rom Northern Portion of Site rom Northern Magnesium (mg/L) L) (mg/L) 2 14 9.5 1.8 1.1 2.4 8.5 Potassium (mg/ Silica as SiO as Silica R ‐ 27 24 6.7 0.021 0.056 0.00048 200 \V \V ‐ / Calcium (mg/L) Calcium Manganese (mg/L) \V \JI / OW -- I \V _/ \V \V -=---- \V \V \JI Summary of Groundwater Data F -...... icarbonate \V \V \V \V \V ND ND ND ND '-... '-..... \V Iron (mg/L) Iron Water Type Type Water Sodium-Chloride O \V \JI \V R ‐ Calcium-Bicarbonate Calcium-B ‐ 0 'V \V \V '-... 200 - 200 ‐ I., ‐ \V \V 200 \JI \V \V \V OW HCOi Cl OW 55-70 55-70 Depth Depth Depth Depth 077 175-190 175-190 \V \V 14.7-24.7 14.7-24.7 - I I \V - OW I ---- \V J \ -~ r------I ~ RD Bedrock Bedrock ‐ ------oo O Deep Bedrock Deep Bedrock ‐ Sample Location Sample Location - 200 - ‐ Unconsolidated Deposits Unconsolidated Deposits \V \V \V ow 200 ‐ ow - 'V OW _/-- OW + \V --- - \V 008 - - \V \V v Well Well --- OW-200-R OW-200-R OW-200-O OW-200-O OW ,J, \V OW-200-RD OW-200-RD _,, \V "----- i rt ------Mg \V po ------\V p --- -...... 079 Su S S H E L--~~==~====~======~==~=-- Figure 29 I 20% 2.0 0.6 -0.8 -2.5 -2.5 -85.1 -85.1 -97.3 -97.3

4

SO 40%

% %

0 8 60% Potential (milliVolts) Potential (milliVolts) Oxidation Reduction Charge Balance (%) I

80%

% %

0 6 Cl 7

14 10

9.0 8.7 9.4

% %

0 % 4 20 --

ulfate (mg/L)

%

0 S 2 % %

20 40

g 3 pH (Standard Units) % O

% % I

0 0

M C 4 2 + % H % Ca 40 60 J K

K

%

0

6 % %

60 80

%

0 8 % 80 3.6 2.9 3.0 143 129 125 3 ‐ Specific (umohs/cm) Conductance

Chloride (mg/L) Chloride Piper Diagram Diagram Piper

% %

0 % 8 80 I

SMW % % % %

0 0

6 % 8 60 J 2 K

‐

l

% %

C % %

0

0

+

K 6 4

4 % + %

K

O 0 a 20 S 4 N

86

% % %

0

‐ 0 2 % 4 20 63.44 11.34 64.66 10.79 11.79 57.34

SMW % %

0 2 0%

4 (Degrees C) Temperature OW 2 ‐ - Bicarbonate (mg/L) I Ca

% 60 - SMW 80% 80% K J

60% 60% % 8.2 4.2 80 6.2

-53.1 -53.1 -52.1 -52.1

-51.8 g g K M (VSMOW) (VSMOW) 40% 40% Deuterium-3 Sodium (mg/L) 20% 20% I HCO, -

1.3 -8.4 0.87 0.64 -8.73 -8.55 (VSMOW) (VSMOW) Oxygen-18 Oxygen-18 Magnesium (mg/L) I L) (mg/L) 2 16 16 1.1 1.7 8.1 3.0 Potassium (mg/ Silica as SiO as Silica I _ ' •, . 20 20 17 3 0.038 0.0048 0.00099 2 ‐ / 'V Calcium (mg/L) Calcium l I Manganese (mg/L) / J I SMW ‐ ---- 'V 'V ___ - ---- SMW 'V w 'V 'V 'V 'V 'V Summary of Groundwater Data From Other Sentry Wells Sentry Wells Data From Other Summary of Groundwater _> ------~------.::::; -- - ND ND 3 0.065 HCO, ‐ I - Iron (mg/L) Iron Water Type Type Water 1 ;i, 'V 'V 'V 'V I -- Calcium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate Calcium-Bicarbonate w w w w 'V 'V I -- I'---- SMW 'V / ...... _ I w 'V -- 'V 'V 'V 'V 'V - , , w w , 008 __.,,.------65-80 65-80 Depth Depth Depth Depth 'V ______,,. 175-190 175-190 81.5-101.5 81.5-101.5 ,,,- 'V 'V 'V OW 'V I w ------'V 'V ,---- ( , 'V ______., -400- '--- 079 ______- '--- ~ R- OW /----- 0 7"! Bedrock Bedrock Bedrock Bedrock - 011 f0 Deep Bedrock Deep Bedrock - - 07 Sample Location Sample Location ~- -+ 1 OW - ,/ ow / - - 86 OW I ‐ ~ I I _ OW c, Well Well SMW3 SMW3 OW-86 OW-86 SMW-2 SMW-2 86 ‐ S - OW I 408 - OW oW-408-D -- + 038 70

60 y = l.147x + 3.1638 R2 = 0. 7523 ..• ..

..· · OW‐401‐RD 50 OW‐406‐R

...· ·

::i" -.. 40 ....·· 0 E ..·· ::::, ..· ·

20 OW,.··· ‐407‐R OW‐41 OW‐112‐R OW‐411‐RD

10 OW‐401‐R OW‐101‐R

0 0 10 20 30 40 50 60 Chloride (mmol/L)

1,4-Dioxane vs. Chloride Groundwater Samples Figure 30

Attachment A

Geochemical Type Pie Charts

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Anion Cation

Sulfate, 54% Sodium, 21%

Manganese, 1% Calcium, 47%

Magnesium, 19% Eastern Ponded Wetland Classification Calcium/Sodium-Sulfate Bicarbonate, 23% Potassium, 8% Iron, 4% Chloride , 23%

Anion Cation

Aluminum, 1% Sodium, 13% Sulfate, 88%

Manganese, 2%

Magnesium, 9%

Calcium, 67% Potassium, 2%

Iron, 6%

Northern Wetland Classification Bicarbonate, 3% Calcium-Sulfate Chloride , 9%

Anion Cation

Sulfate, 51%

Sodium, 24%

Manganese, 1% Calcium, 53% Chloride , 24%

Magnesium, 18% Latham Brook Classification Calcium-Sulfate Bicarbonate, 25% Potassium, Iron,4% 0% Anion Cation

Sodium, 15% Sulfate, 30% Chloride , 21%

Manganese, 3% Calcium, 31%

Magnesium, 8%

Potassium, 4%

OW-93-O Classification Iron, 39% Calcium/Iron -Bicarbonate/Sulfate Bicarbonate, 49%

Anion Cation

Sodium, 16% Chloride , 39% Sulfate, 11%

Manganese, 3% Calcium, 58% Magnesium, 9%

Potassium, 5% OW-409-D Classification Iron, 9% Calcium - Bicarbonate Bicarbonate, 50%

Anion Cation

Sulfate, 13% Chloride , 25% Sodium, 26%

Calcium, 46%

Manganese, 2%

Magnesium, 12% OW-408-D Classification Potassium, 13% Calcium/Sodium - Bicarbonate Bicarbonate, 62% Iron, 1%

Anion Cation

Sulfate, 16% Chloride , 15%

Sodium, 31%

Calcium, 47%

Manganese, 0%

Magnesium, 11% OW-112-O Classification Calcium/Sodium - Bicarbonate Bicarbonate, 69% Potassium, 11%

Anion Cation

Sulfate, 9% Sodium, 18% Chloride , 19%

Manganese, 5%

Calcium, 58% Magnesium, 7%

Potassium, 4% OW-43 Classification Iron, 8% Calcium - Bicarbonate Bicarbonate, 72% Anion Cation

Sulfate, 26% Sodium, 20% Chloride , 18%

Calcium, 36%

Manganese, 6%

Magnesium, 11% OW-51 Potassium, 4% Classification Bicarbonate, 56% Calcium/Iron - Bicarbonate Iron, 23%

Anion Cation

Sulfate, 24% Sodium, 20% Chloride , 9%

Manganese, 0% Calcium, 42%

Magnesium, 30% OW-111-O Classification Bicarbonate, 67% Iron, 1% Calcium/Sodium - Bicarbonate Potassium, 7%

Anion Cation Sodium, 62%

Chloride , 78%

Manganese, 0%

Magnesium, 7% Sulfate, 14% OW-200-O Potassium, 3% Classification Bicarbonate, 8% Sodium - Chloride Calcium, 28% Anion Cation

Chloride , 93% Sodium, 14%

Manganese, 0% Magnesium, 6% Potassium, 0% Iron, 1%

Calcium, 79%

OW-401-RD Sulfate, 0% Classification Calcium - Chloride Bicarbonate, 7%

Anion Cation

Sulfate, 8% Chloride , Sodium, 23% 23%

Manganese, 4%

Calcium, 57% Magnesium, 8% OW-101-R Potassium, 3% Classification Iron, 5% Calcium - Bicarbonate Bicarbonate, 69%

Anion Cation

Chloride , 84% Sodium, 20%

Manganese, 0%

Magnesium, 8% Calcium, 71%

Potassium, 1% Iron, 0%

OW-411-RD Sulfate, 0% Classification Calcium - Chloride Bicarbonate, 16%

Anion Cation

Chloride , 64%

Sodium, 26%

Manganese, 2% Calcium, 59% Magnesium, 7%

Potassium, 2% OW-406-R Iron, 4% Classification Calcium - Chloride Bicarbonate, 36%

Anion Cation

Chloride , 57%

Sodium, 37%

Calcium, 46% Sulfate, 13%

OW-404-R Manganese, 4% Classification Magnesium, 5% Calcium/Sodium - Chloride Bicarbonate, 30% Potassium, 4% Iron, 4% Anion Cation

Chloride , 91% Sodium, 22%

Manganese, 0% Calcium, 72% Magnesium, 4% Potassium, 2% Iron, 0%

OW-112-R Sulfate, 2% Classification Calcium - Chloride Bicarbonate, 7%

Anion Cation

Sulfate, 6% Chloride , 4%

Sodium, 36%

Calcium, 60% Manganese, 0% Magnesium, 3% OW-407-RD Potassium, 1% Classification Iron, 0% Calcium - Bicarbonate Bicarbonate, 90%

Anion Cation

Chloride , 90%

Sodiu , 24%

Manganese, 1% Calciu , 70% Magnesiu , 4% Potassiu , 1% Iron, 0% OW-407-R Classification Sulfate, 3% Calcium - Chloride Bicarbonate, 7% Anion Cation

Chloride , 51% Sodium, 23%

Sulfate, 6%

Manganese, 2% Calcium, 62% Magnesium, 7%

Potassium, 3% Iron, 3% OW-041 Classification Calcium - Chloride Bicarbonate, 43%

Anion Cation

Chloride , 73% Sodium, 18%

Manganese, 1%

Magnesium, 16% Calcium, 62%

Sulfate, 2% Potassium, 3% OW-401-R Iron, 0% Classification Calcium - Chloride Bicarbonate, 25%

Anion Cation

Sulfate, 10% Chloride , 8% Sodium, 22%

Magnesium, 7% Calcium, 66%

Potassium, 5%

OW-105-R Classification Bicarbonate, 82% Calcium - Bicarbonate

Anion Cation

Sulfate, 15% Chloride , 5%

Sodium, 28%

Calcium, 61% Manganese, 0%

Magnesium, 7%

Potassium, 4% OW-105-RD Classification Calcium - Bicarbonate Bicarbonate, 80%

Anion Cation

Sodium, 55% Sulfate, 16% Chloride , 13%

Aluminum, 1% Manganese, 0% Magnesium, 2%

Potassium, 6% Iron, 0% OW-111-R Classification Bicarbonate, 71% Calcium, 36% Sodium - Bicarbonate Anion Cation

Chloride , 39% Sodium, 57% Sulfate, 24%

Manganese, 0%

Magnesium, 3% Potassium, 3% Iron, 0% Aluminum, 1%

OW-111-RD Bicarbonate, 37% Calcium, 36% Classification Sodium - Chloride/Bicarbonate

Anion Cation

Sodium, 49% Sulfate, 17% Chloride , 11%

Manganese, 0% Magnesium, 3% Calcium, 43% Potassium, 5% Iron, 0% OW-80 Classification Sodium/Calcium - Bicarbonate Bicarbonate, 72%

Anion Cation

Sulfate, 10% Sodium, 20% Chloride , 36%

Manganese, 1%

Magnesium, 9%

Calcium, 63% Potassium, 7% Iron, 0% OW-33 Classification Calcium - Bicarbonate Bicarbonate, 54%

Anion Cation

Chloride , 46% Sulfate, 8% Sodium, 32%

Calcium, 59% Manganese, 0% Magnesium, 4% OW-410-R Potassium, 5% Classification Calcium - Chloride/Bicarbonate Bicarbonate, 46%

Anion Cation

Sulfate, 11% Sodium, 17%

Chloride , 7% Manganese, 0% Magnesium, 3%

Potassium, 4% Calcium, 76%

OW-200-R Classification Calcium - Bicarbonate Bicarbonate, 82% Anion Cation

Sulfate, 17%

Sodium, 22% Chloride , 7%

Manganese, 0% Magnesium, 4% Calcium, 68%

Potassium, 6%

OW-SMW-2 Classification Calcium - Bicarbonate Bicarbonate, 76%

Anion Cation

Sulfate, 10% Sodium, 15%

Manganese, 0% Chloride , 5% Magnesium, 2% Potassium, 3%

Calcium, 80%

OW-200-RD Classification Calcium - Bicarbonate Bicarbonate, 85%

Anion Cation

Sulfate, 14% Sodium, 14% Chloride , 6% Manganese, 0% Magnesium, 6%

Potassium, 3% Iron, 0%

Calcium, 77%

OW-86 Classification Bicarbonate, 80% Calcium - Bicarbonate

Anion Cation

Sulfate, 20%

Sodium, 24% Chloride , 7%

Manganese, 0% Calcium, 67% Magnesium, 7%

Potassium, 2% SMW-3 Classification Calcium - Bicarbonate Bicarbonate, 73%

Attachment B

Stiff Diagrams

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Latham Brook

~

-~-----+------~ ------00:

+K------

Unconsolidated Deposit Wells

OW-51

------SO

ca ------

+K------

OW-43

2.0 1 "'

t , ------:::,,----tr-----=------00

OW-408D

1 -

------00

C.3 ------

+K------

OW-409D

------00

C.3 -- --- :CO..

+ K------

OW-111-O

5 1-5

------00

C.3 ------

+ K------

OW-200-O

1-5 5

------00·

+K------

Shallow Bedrock Wells

OW-404-R

15 1(J 0 10 15

------00

OW-101-R

(l.5

rCa -

+ K------

OW-406-R

15 10 5 (l 5 10 15

------~

ca --

OW-112-R

10 5 5 10

------~

ca ------r ~

+ K------

OW-407-R

10 5 0 5 10

------00

ca ---

+ K------

OW-200-R

1.(1 Q.(I 1.(1

ca -

+ K------Cl

SMW-2

OW-41

3.

------SO

C3 --

OW-33

------SO

C3 -

OW-111-R

Q.6

OW-80

+K------

OW-105-R

1.0 0.5 0.0 0.5 1.0

Mg SO4

Ca HCO3

+ K Cl

OW-86

.0

------00

ca -

+K------

Deep Bedrock Wells

OW-401-RD

0

------SO

OW-401-R

10 10

------00

+ K------

OW-411-RD

10 0 10

------so~

ca -- --

+ t< ------

OW-407-RD

0 1 ~,

------SO

OW-200-RD

1 C 1..0 1..0 1..5

+K------

OW-410-R

a.o

------oo.

OW-111-RD 0

------SO

OW-105-RD

1..0

------00

+K------

SMW-3

------00

+K------Surface Water

Eastern Ponded Wetlands

1-0 Q:5 1..5

------so~

+ K------

Northern Wetlands

1 .

------_,,.------::..-so

ca -

+

Attachment C

URI Dataset

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E S N 10 20 Miles

W

d d 10 0

n

u

o

S

d

n

a

sl

I

MA

k

c

o

l

B

Rhode Island CT CT Pawcatuck River River Pawcatuck Watershed Precipitation Data

UA ID URI ID Basin Ppt amt d18O dD W7209 Rich ppt 8/8/99 Queen 1 -5.5 -31 W7215 Rich ppt 8/14/99 Queen 0.25 -2.5 -15 W7212 Rich ppt 8/15/99 Queen 0.5 -2.6 -14 W7216 Rich ppt 8/26/99 Queen 0.5 -3.1 -16 W7221 Rich ppt 9/6/99 Queen 0.5 -2 -8 W7205 Rich ppt 9/8/99 Queen 1 -5.3 -33 W7229 Rich ppt 9/10/99 Queen 1.5 -7.4 -47 W7230 Rich ppt 9/11/99 Queen 1.5 -6.8 -44 W7213 Rich ppt 9/16/99 Queen 1 -4.7 -27 W7203 Rich ppt 9/17/99 Queen 1.5 -2.6 -14 W7206 Rich ppt 9/30/99 Queen 0.5 -3.9 -17 W7211 Rich ppt 10/4/99 Queen 1 -5.1 -24 W7208 Rich ppt 10/14/99 Queen 1 -6.9 -40 W7207 Rich ppt 10/18/99 Queen 2.5 -8.8 -54 W7210 Rich ppt 11/2/99 Queen 1.5 -5.7 -33 W7310 Rich ppt 12/7/99 Queen 1.5 -8.2 -53 W7202 Rich ppt 1/4/00 Queen 1 -6.9 -45 W7204 Rich ppt 1/10/00 Queen 1.25 -8.3 -52 W7217 Rich ppt 1/13/00 Queen 0.5 -8.7 -46 W7309 Rich ppt 1/20/00 snow 0.125 Queen -31 -226 W8198 Rich ppt 1/25/00 Queen 0.3 -15.9 -114 W8199 Rich ppt 1/31/00 Queen 0.5 -13 -81 W8200 Rich ppt 2/3/00 snow 0.5 Queen -13.2 -94 W8201 Rich ppt 2/18/00 snow 1.5 Queen -8.8 -55 W8202 Rich ppt 2/24-25/00 Queen 0.75 -7.9 -45 W8203 Rich ppt 3/11-12/00 Queen 2.25 -4.1 -18 W8204 Rich ppt 4/4/00 Queen 0.25 -2.5 -14 W8205 Rich ppt 4/19/00 Queen 0.75 -7.4 -50 W8206 Rich ppt 4/22/00 Queen 1 -5.9 -36 W8207 Rich ppt 5/11/00 Queen 1 -4.5 -28 W8208 Rich ppt 5/13/00 Queen 0.5 -2.8 -13 W8209 Rich ppt 5/22/00 Queen 1 -7.3 -47 W8210 Rich ppt 6/6-7/00 Queen 2.5 -8.3 -54 W8211 Rich ppt 6/14/00 Queen 0.5 -4.6 -27 W8212 Rich ppt 6/21/00 Queen 1 -5.1 -32 W8213 Rich ppt 7/15-16/00 Queen 1.5 -4.2 -22 W8214 Rich ppt 7/31/00 Queen 2.25 -6.4 -39 W8215 Rich ppt 8/7/00 Queen 0.75 -3.9 -19 W8216 Rich ppt 8/14/00 Queen 0.75 -7.2 -48 W8217 Rich ppt 8/15-16/00 Queen 1 -5.4 -31 Groundwater Data

UA ID URI ID Basin d18O dD W7425 144 Hundred Acre Pond rd Pawcatuck -7.1 -41 W7411 154 Hundred Acre Pond Rd Pawcatuck -7.8 -49 W7424 17 Clarks fall 8/25/99 Pawcatuck -7 -39 W7333 181 Hundred Acre Pon 10/11/99 Pawcatuck -7.7 -48 W7417 21 Boom Bridge Rd Pawcatuck -7.6 -45 W7410 250 Spring St. Pawcatuck -7.4 -44 W7402 27 Skunk Hill Rd Pawcatuck -6.2 -38 W7423 296 Dugway Bridge Rd Pawcatuck -6.9 -38 W7412 298 Hillsdale Rd Pawcatuck -7.8 -47 W7419 3 Boom Bridge Rd Pawcatuck -6.9 -40 W7329 33 Boom Bridge Rd 10/9/99 Pawcatuck -7.8 -49 W7332 336 Dug Way Br. Rd 10/13/99 Pawcatuck -7.6 -47 W7420 36 Hundred Acre Pond Rd Pawcatuck -7.2 -43 W7408 46 Kenyon School Rd Pawcatuck -7 -41 W7317 50 Pleasant View Dr. Pawcatuck -8.1 -50 W7422 544 Dugway Bridge Rd Pawcatuck -6.9 -40 W7426 710 Alton Carolina Rd Pawcatuck -7.1 -41 W7409 76 Old Usquepaugh Rd Pawcatuck -7.2 -43 W7421 80 Sir Micheal Dr Pawcatuck -8.1 -49 W7315 97 Waites Corner Rd Pawcatuck -7.4 -47 W7427 Woodville Rd 8/24/99 Pawcatuck -7.4 -43 Surface Water Data

Hundred Usquepaugh Chipuxet Acre Barber Worden Beaver Location ID Yawgoo #1 Yawgoo #2 Yawgoo #3 #4 #5 Pond #6 Pond #7 Pond #8 #9 DATE d18O d18O d18O d18O d18O d18O d18O d18O d18O 6/9/1999 -5.7 -6.4 -6.2 -6.8 6/14/1999 -4.8 6/15/1999 -4.0 6/20/1999 -5.8 -6.2 -6.5 7/5/1999 -5.5 -5.4 -4.4 -6.4 7/7/1999 -2.7 7/8/1999 -5.3 -5.9 -6.0 7/19/1999 -5.0 -5.7 -6.1 8/11/1999 -5.1 -1.2 8/19/1999 8/23/1999 -4.6 -5.8 -6.2 -6.6 8/24/1999 8/25/1999 -5.1 -3.8 -0.7 -6.9 9/21/1999 -5.2 -5.2 -4.0 9/22/1999 9/24/1999 -1.7 -6.3 9/29/1999 10/2/1999 -5.4 10/7/1999 -5.4 -5.2 -3.9 -6.3 10/9/1999 10/12/1999 -5.1 -5.8 -5.5 -6.6 -2.9 10/16/1999 -6.1 10/21/1999 -5.5 -5.4 -4.2 10/24/1999 -6.5 11/7/1999 -5.7 -5.6 -4.1 -5.5 -6.4 11/22/1999

June avg -5.8 -6.3 -6.4 -6.8 -4.8 -4.0 July avg -5.2 -5.8 -6.1 -5.5 -5.4 -4.4 -2.7 -6.4 August avg -4.6 -5.8 -6.2 -6.6 -5.1 -3.8 -1.0 -6.9 Sept avg -5.2 -5.2 -4.0 -1.7 -6.3 Oct avg -5.1 -5.6 -5.5 -6.6 -5.5 -5.3 -4.1 -2.9 -6.3 Nov avg -5.7 -5.6 -4.1 -5.5 -6.4 Surface Water Data

Wood Pawcatuck Chickasheen Pawcatuck (SkunkHill) Sawmill Green Ashaway Bradford (Boom Location ID #10 #11 Alton #12 #13 #14 Falls #15 #16 #17 Bridge) #18 DATE d18O d18O d18O d18O d18O d18O d18O d18O d18O 6/9/1999 6/14/1999 6/15/1999 -5.4 6/20/1999 7/5/1999 -5.5 7/7/1999 -5.8 -6.3 7/8/1999 7/19/1999 8/11/1999 8/19/1999 -6.7 -4.1 -4.7 -6.3 -6.3 8/23/1999 8/24/1999 -6.7 -2.6 -4.9 8/25/1999 -6.2 -5.8 9/21/1999 -5.5 9/22/1999 -5.5 -5.4 -5.9 -3.3 -5.6 -5.8 -5.7 9/24/1999 9/29/1999 -6.1 -3.6 -5.7 -6.1 -5.8 10/2/1999 10/7/1999 -5.4 10/9/1999 -5.6 -5.6 -5.6 -5.8 -5.7 -5.6 10/12/1999 10/16/1999 -5.8 -5.8 -5.9 -4.0 -5.9 -5.7 10/21/1999 -5.8 10/24/1999 -6.1 -6.1 -6.4 -4.0 -6.1 -6.2 -6.0 -6.0 11/7/1999 -5.0 11/22/1999 -6.4 -4.8 -6.1 -5.6 -6.0 -6.1

June avg -5.4 July avg -5.5 -5.8 -6.3 August avg -6.2 -6.7 -3.4 -4.8 -6.3 -6.1 Sept avg -5.5 -5.5 -5.4 -6.0 -3.5 -5.7 -6.0 -5.7 -5.8 Oct avg -5.6 -5.8 -5.8 -6.2 -4.0 -5.9 -6.0 -5.8 -5.8 Nov avg -5.0 -6.4 -4.8 -6.1 -5.6 -6.0 -6.1 Surface Water Data

Hundred Usquepa Chipuxet Acre Barber Worden Beaver Chickash Location ID Yawgoo #1 Yawgoo #2 Yawgoo #3 ugh #4 #5 Pond #6 Pond #7 Pond #8 #9 een #10 DATE dD dD dD dD dD dD dD dD dD dD 6/9/1999 -37 -40 -40 -40 6/14/1999 -34 6/15/1999 -29 -38 6/20/1999 -35 -38 -39 7/5/1999 -38 -37 -32 -40 -36 7/7/1999 -24 7/8/1999 -37 -41 -42 7/19/1999 -34 -37 -39 8/11/1999 -33 -17 8/19/1999 8/23/1999 -32 -36 -40 -40 8/24/1999 8/25/1999 -34 -31 -13 -42 9/21/1999 -36 -35 -31 -38 9/22/1999 9/24/1999 -19 -40 9/29/1999 10/2/1999 -35 10/7/1999 -35 -34 -27 -37 -37 10/9/1999 10/12/1999 -31 -34 -34 -38 -20 10/16/1999 -35 10/21/1999 -37 -34 -28 -37 10/24/1999 -40 11/7/1999 -36 -34 -28 -31 -37 -33 11/22/1999

June avg -36 -39 -40 -40 -34 -29 -38 July avg -36 -39 -41 -38 -37 -32 -24 -40 -36 August avg -32 -36 -40 -40 -34 -31 -15 -42 Sept avg -36 -35 -31 -19 -40 -38 Oct avg -31 -35 -34 -38 -36 -34 -28 -20 -37 -37 Nov avg -36 -34 -28 -31 -37 -33 Surface Water Data

Wood Pawcatuck Pawcatuck (SkunkHill) Sawmill Green Ashaway Bradford (Boom Location ID #11 Alton #12 #13 #14 Falls #15 #16 #17 Bridge) #18 DATE dD dD dD dD dD dD dD dD 6/9/1999 6/14/1999 6/15/1999 6/20/1999 7/5/1999 7/7/1999 -38 -40 7/8/1999 7/19/1999 8/11/1999 8/19/1999 -43 -30 -32 -38 -36 8/23/1999 8/24/1999 -42 -24 -34 8/25/1999 -39 -37 9/21/1999 9/22/1999 -34 -35 -37 -24 -34 -37 -35 9/24/1999 9/29/1999 -40 -27 -34 -39 -35 10/2/1999 10/7/1999 10/9/1999 -37 -37 -35 -37 -37 -37 10/12/1999 10/16/1999 -34 -35 -36 -29 -38 -35 10/21/1999 10/24/1999 -36 -37 -40 -29 -38 -38 -39 -35 11/7/1999 11/22/1999 -38 -32 -36 -37 -36 -36

June avg July avg -38 -40 August avg -39 -43 -27 -33 -38 -37 Sept avg -34 -35 -39 -26 -34 -38 -35 -35 Oct avg -36 -36 -38 -29 -37 -38 -37 -36 Nov avg -38 -32 -36 -37 -36 -36