Fiore, Shawn To RONALD MURAWSKI 370339

"Fiore, Shawn" <SFiore@haleyaldrich .c»m>

08/30/2004 05:06 PM

EPA Region 5 Records Ctr.

To RONALD MURAWSKI _ 370339

cc jkeiserl, jyl.lapachin, dvoight, "Hagen, David"

bcc

Subject RE: FINAL DSP COMMENTS LETTER

Ron -Attached please find our draft Work Plan Addendum, for your review. Note that this document (along with attached figures and tables) are formated to fit into Section 3 of the final Data Submittal Package/Work Plan Addendum when this document combined and finalized .

Note that a PDF version of the entire document is included, along with a version of the text in MSWORD.

If you have any questions or need any additional information, please contact us.

Regards, Shawn

3.0 WORK PLAN ADDENDUM

Activities to be completed during Field Effort 2 of the Remedial Investigation at the Tremont City Landfill BFOU are detailed below. These activities are based on results of Field Effort 1 activities as discussed in previous sections. Methods and procedures to complete the Field Effort 2 scope of work are described in the Final SSP (Haley & Aldrich, July 2003) and are consistent with the Administrative Order by Consent (AOC) and related Scope of Work (SOW), entered and agreed to by the Performing Respondents on 3 October 2002

3.1 Work Plan Addendum - Field Effort 2

Based on the results of RI Field Effort 1, several data gaps were identified that will require additional assessment as a part of Field Effort 2. These data gaps are summarized below, followed by a summary of the Field Effort 2 Work Plan.

3.1.1 Data Gap Summary

These data gaps include:

The downgradient extent of COCs in groundwater exceeding screening criteria in shallow monitoring well HMW-301 needs to be determined. The water table unit monitoring network needs to be enhanced downgradient (east) of the BFOU. The relationship between shallow groundwater and the unnamed tributary needs to be evaluated. An evaluation of background concentrations of arsenic, antimony and manganese in groundwater needs to be completed. An evaluation of BHC and alpha chlordane in groundwater needs to be completed. The gradient and flow direction in the deep sand and gravel unit on the western portion of the barrel fill needs to be ascertained. Vertical and horizontal groundwater flow (flux) and the vertical hydraulic conductivity of selected hydrosratigraphic units beneath the site need to be determined. / The presence and magnitude of 1,1-dichloroethane concentrations detected in stream sediment samples needs to be verified. No sidewall sample was collected from Test Pit D-7 during Field Effort 1.

3.1.2 Field Effort 2 Work Plan Summary

In order to fill the above listed data gaps, several additional task items are proposed for Field Effort 2. These include: • One additional shallow, water table unit well will be installed downgradient of

HMW-301 to define the horizontal extent of COCs exceeding screening criteria. • Three additional shallow, water table unit wells will be installed downgradient of the

BFOU to enhance the water table unit monitoring network. • Surface water gauging will be completed along the unnamed tributary located east of

the BFOU to define the relationship between shallow groundwater and surface water in this area.

• Two additional rounds of groundwater sampling will be completed to evaluate groundwater quality at the site. Samples from each well will be analyzed for TAL/TCL constituents. Statistical evaluation of total metals analyses will be used to define background concentrations for those metals exceeded screening criteria.

• Three piezometers will be installed into the deep sand and gravel unit to aid in defining the hydrogeologic relationship between the BFOU and landfill and to determine the groundwater gradient in this unit on the western portion of the BFOU.

• Additional groundwater level monitoring will be performed in wells installed in each hydrogeologic unit to better define groundwater flow directions, gradients, and the variability associated with each unit.

• Aquifer (pump) testing will be completed to characterize vertical groundwater flux and other hydrogeologic characteristics of the hydrogeologic units beneath the site.

• Additional sediment samples will be collected from the unnamed tributary, in the vicinity of SE-02, to confirm the presence of estimated concentrations of 1,1-dichloroethane detected.

• One "side wall" sample will be collected, utilizing drilling techniques, from adjacent to waste cell D-7 during Field Effort 2, to meet the requirements of the SSP.

All activities discussed herein will be completed following procedures outlined in the Final RI/FS Support Sampling Plan (SSP; Haley & Aldrich, Inc., July 2003) except those activities with procedures not included in the SSP. Procedures for those activities not addressed by the SSP are discussed in greater detail in the following sections.

3.2 Groundwater Investigation Work Scope

As detailed in the SSP and summarized in the Data Report, the primary decision for the groundwater investigation was to determine whether or not on-site groundwater quality met the federal drinking water standards published as the Maximum Contaminant Levels (MCLs) by the USEPA Office of Water, or if MCLs do not exist, other applicable screening criteria. A secondary decision for the groundwater investigation was to determine whether or not off-site impacts currently exist or are likely to exist in the future from the observations conducted at on-site groundwater monitoring wells. The decision rules for the groundwater investigation are:

• If the concentrations of TCL organics and TAL inorganics detected in groundwater samples collected from monitoring wells are less than their respective MCLs (or if MCLs do not exist, other applicable screening criteria) then, the vertical and horizontal extent of impacted groundwater has been defined;

• Based on hydrogeologic testing to be completed during the initial field investigation and knowledge of potential future migration pathways, if the concentrations of TCL organics and TAL inorganics detected in groundwater samples collected from monitoring wells are less than their respective MCLs (or if MCLs do not exist, other applicable screening criteria), then the potential for vertical and horizontal extent of impacted groundwater has been defined;

• For TAL metals, if concentrations exceed MCLs (or if MCLs do not exist, other applicable screening criteria) and are less than background, then the extent of impacted groundwater from TAL metals has been delineated.

Based-on the data presented above, it appears that these decision criteria have not been met in several specific instances. In addition, groundwater flow has not been ascertained in the deep sand and gravel on the western portion of the site and the water table unit monitoring network is insufficient on the eastern portion of the, BFOU. Therefore, additional groundwater investigation activities to obtain information to meet these criteria are proposed, as described below.

3.2.1 Groundwater Quality - Volatile Organic Compounds

A. Data Gap

Groundwater samples collected from the water table well HMW-301 contained concentrations of several constituents in excess of screening criteria. Samples from wells located in the same well cluster, but screened in lower units (1075 sand, 1050 sand and deep sand and gravel units) contained no concentrations of any COC in excess of screening criteria^ Evaluation of these data, based on review of the decision criteria presented above indicates that while the vertical extent of these compounds has been determined, the horizontal, downgradient extent has not.

B. Field Effort 2 Work Scope

In order to fill the above data gap, one additional monitoring well, installed and screened in the water table unit, will be installed downgradient of HMW-301, as depicted in Figure 26. The procedures that will be used to drill, install, monitor, and sample this well are those provided in the final SSP, including:

2.2 Drilling Techniques/Background Information; 2.3 Soil Borings; 2.5 Soil Classification; 3.1 Well Construction Materials; 3.2 Procedures for Overburden Monitoring Well Installation; 3.3 Well Development; 4.1 Manual Water Level Measurement Procedure; 5.2 Groundwater Sampling; 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.

3.2.2 Groundwater Quality - Pesticides

A. Data Gaps

• Beta-BHC: Groundwater samples collected from the water table well HBF-5B contained a concentration of a pesticide, beta-BHC (0.1 ug/1), in excess of screening

criteria. Samples from all other wells constructed in the water table unit, as well as all other hydrogeologic units identified at the site, contained no concentrations of this compound. Further, based on review of groundwater flow directions in the water table unit, this well appears to be upgradient to the BFOU. Based on the potential for an agricultural source for this pesticide compound, the upgradient position of the well, and the singular detection, it appears that this compound is likely related to upgradient, off-site issues. Therefore, additional investigative activities related to this detection, except re-sampling of all wells to determine the reproducibility of this occurrence, are not warranted.

• Alpha Chlordane: Groundwater samples collected from the 1075 Sand well HBW-204 contained an estimated concentration of a pesticide, alpha chlordane (0.17 J ug/1), in excess of screening criteria. Samples from all other wells constructed in the water table unit, as well as all other hydrogeologic units identified at the site, contained no concentrations of this compound. Based on the potential for an agricultural source for this pesticide compound, the estimated-quantification of the reported concentration, the upgradient position of the well, and the singular detection, it appears that this compound is likely related to upgradient, off-site issues. Therefore, additional investigative activities related to this detection, except resampling of all wells to determine the accuracy of the estimated concentration and reproducibility of this occurrence, are not warranted.


In order to fill the above data gap, several rounds of groundwater level gauging will be completed, with the resulting data used to define groundwater flow direction and upgradient monitoring well locations. This information will be used to define potential sources.

Two additional rounds of groundwater sampling and analysis (for TAL/TCL compounds) will also be completed. Results of these analyses will be used to determine if these two pesticides, in fact, are present in groundwater beneath the site.

The procedures that will be used to monitor and sample this well are those provided in the final SSP, including: • 4.1 Manual Water Level Measurement Procedure; • 5.2 Groundwater Sampling; • 9.0 Waste Characterization - Investigation Derived Wastes; and • 8.0 Equipment Decontamination.

3.2.3 Groundwater Quality - Metals

A. Data Gaps

Arsenic, antimony and manganese were detected in several wells at concentrations exceeding screening criteria. Each of these compounds are naturally occurring and are historically present, at varying concentrations, in many areas within Ohio. Accordingly, comparison of these compounds to background concentrations is necessary to determine if these compounds are related to past site activities or are simply present at naturally occurring levels. Each of these compounds were detected during RI Field Effort 1 activities as described below:

• Arsenic: Arsenic was detected in groundwater samples collected from 48 monitoring wells during this sampling event. Seventeen wells had concentrations in excess of the screening criterion (10 ug/1), the highest concentration of which was detected in monitoring well BF-23D (26.4 ug/1). These wells were located both upgradient and downgradient of the BFOU and were screened within all intervals. Further, arsenic was the only compound detected in any soil at a concentration exceeding the screening criterion. This concentration was detected in a background surface soil sample (BK-5).

• Antimony: Antimony was detected in samples from two monitoring wells (BF-19S and BF-23DD) at concentrations exceeding screening criteria. These wells are constructed in different hydrogeologic units (1075 sand and 1050 sand, respectively) and are located at some distance from each other, with both potentially being situated upgradient of the BFOU.

• Manganese: Manganese was detected in samples from two monitoring wells (HMW-301 and BF-22S) at concentrations exceeding screening criteria. These wells are constructed in different hydrogeologic units (water table and 1075 sand, respectively) and are located at some distance from each other (HMW-310 is near the southern portion of the BFOU, while BF-22S is north of the BFOU).


In order to fill the above data gap, several rounds of groundwater level gauging will be completed, with the resulting data used to define groundwater flow direction and upgradient monitoring well locations. Two additional rounds of additional groundwater sampling and analysis (for TAL/TCL compounds) will also be completed. Results of these analyses will be used to determine the concentrations of these metals present in groundwater beneath the site.

After the above activities are completed, a statistical evaluation of laboratory data will be completed to determine if concentrations of these metals are within expected background concentration ranges. Statistical methods to be used will be based on the characterisdcs of the data collected (e.g. parametric, non-parametric, etc.).


Planned analyses are summarized in Table 18. Laboratory procedures that will be used to analyze each of the samples collected are provided in Appendix B of the Final QAPP (Haley & Aldrich, July 2003).

3.2.4 Water Table Unit Monitoring Well Network Enhancement

A. Data Gap

Evaluation of groundwater elevation data from wells screened in the water table unit (Figure 26) indicates that the current monitoring network is insufficient for long term monitoring of groundwater flow and quality downgradient (east) of the BFOU. During Field Effort 1, one monitoring well (HMW-301) located downgradient of the BFOU was sampled. A second well (HCW-1) was dry during this sampling event, but based on recent monitoring, now contains several feet of water. Additional wells are necessary to better define long-term groundwater flow and quality in this area.


To fill the data gap described above, three shallow monitoring wells, installed and screened in the water table unit, are proposed. These wells will be installed as follows: • One well will be installed midway between HMW-301 and HBF-14; • One well will be Installed midway between HCW-1 and HMW-301; and • One well will be installed north of HCW-1, along the northern boundary of the BFOU.

The proposed locations of these monitoring wells are depicted on Figure 26. The procedures that will be used to drill, install, and monitor these wells are those provided in the final SSP, including; • 2.2 Drilling Techniques/Background Information; • 2.3 Soil Borings; • 2.5 Soil Classification; • 3.1 Well Construction Materials; • 3.2 Procedures for Overburden Monitoring Well Installation; • 4.1 Manual Water Level Measurement Procedure; • 9.0 Waste Characterization - Investigation Derived Wastes; and • 8.0 Equipment Decontamination.

3.2.5 Groundwater Flow in Deep Sand and Gravel Unit

A. Data Gap

Evaluation of groundwater elevation data from wells screened in the deep sand and gravel unit indicates that additional investigation is needed to better define the flow direction in the western portion of the deep sand and gravel unit. Existing monitoring wells screened in this unit indicate a head difference of 0.02 feet across the entire BFOU. A more significant head difference is needed to define the groundwater flow direction and to determine the hydrogeologic effects of the Tremont City Landfill on this unit.


To fill the data gap described above, three deep piezometers, installed and screened in the deep sand and gravel, are proposed. These piezometers will be installed as follows: one north of the BFOU, one west of the BFOU, and one south of the BFOU, each within the western portion of the sand and gravel unit (west of the apparent flow boundary). The proposed locations of these piezometers are depicted on Figure 26. The procedures that will be used to drill, install, and monitor these piezometers are those provided in the final SSP, including:

2.2 Drilling Techniques/Background Information; 2.3 Soil Borings; 2.5 Soil Classification; 3.1 Well Construction Materials; 3.2 Procedures for Overburden Monitoring Well Installation; 4.1 Manual Water Level Measurement Procedure; 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.

3.2.6 Hydrogeology - Vertical Flux

A. Data Gap

Although a significant amount of data has been collected regarding the hydrogeology of the BFOU, little information has been obtained on the vertical and horizontal groundwater flux. These data will be crucial in defining future risk scenarios for the BFOU area.


To fill this data gap, three aquifer tests will be completed at the BFOU. The tests will be conducted at locations depicted in Figures 27 -29. In general, the aquifer tests will consist of low volume long duration tests, pumping from the 1050 sand zone. This type of test is based on:

• Reviews of historic aquifer tests conducted near the BFOU; and

• Field Effort 1, Including in-situ hydraulic conductivity test results, permeability test results from shelby tube samples, well development observations, groundwater elevation data and stratigraphic information; and

The results of the review of historic pump tests and Field Effort 1 hydrogeologic data indicate that a constant pumping rate of approximately 0.1 to 0.2 gallons per minute (gpm) over a time period of approximately five days at the proposed aquifer test locations should be adequate to quantify horizontal hydraulic conductivity of the 1050 sand zone and the vertical hydraulic conductivity of the tills overlying the 1050 sand zone. The locations of the tests were chosen based on the stratigraphy anticipated to be encountered and to provide aerial coverage of the BFOU. Specifically, it is anticipated that the 1050 sand zones encountered at each of these locations will have the potential to sustain the pumping rate and duration discussed above. Please note that because of variability in the stratigraphy at the BFOU (i.e. ' variable thickness and location of sand units) the possibility exists that these proposed locations will not be suitable to obtain the design pumping rates and duration needed to quantify groundwater velocity and flux. In the event that initial drilling activities Indicate the location is not suitable, alternate locations will be used.

At each of these locations, a pumping well will be installed in the targeted 1050 sand zone using procedures for well installation activities described in the SSP (procedures listed below). Pumping well design will differ slightly from the design of monitoring wells Installed during Field Effort 1 with the intent to maximize the specific capacity and efficiency of the wells. The pumping wells will be Installed in 8-inch diameter borings and consist of a 4-inch diameter, 0.010 slot stainless steel well screens. The screen Intervals will be designed to match the thickness of the targeted sand zone. The sand pack will consist of waished silica sand of the appropriate size for the screen. In addition to the pumping well, observation wells will be used in conjunction with existing monitoring wells to monitor groundwater elevations in different hydrogeologic units adjacent to the pumping well at each aquifer test location. The observation wells will target the 1050 sand zone and the 1075 sand zone. In general, the 1050 sand zone will be monitored at distances of 25 ft. and 100 ft. away from the pumping well. Approximately two 1075 sand zone observation wells will be Installed 10 and 20 ft. away from the pumping well. Details of pumping well and observation wells are detailed below for each test. The procedures that will be used to drill, install, and monitor these observation wells are those provided in the final SSP, including:


After all pumping well and observation well installations and prior to any aquifer testing (pumping) activities, continuous water levels will be measured for approximately 5 to 10

days in the newly installed pumping wells and observadon wells and in selected existing monitoring wells (approximately 25 wells total) using data loggers. These data will be used to establish background trends in the hydrogeologic regime. In addition, water levels in all existing BFOU monitoring wells will be measured at least twice during this time period.

Prior to beginning individual aquifer tests, data loggers will be left in the pumping well and observation wells and moved to selected monitoring wells in the anticipated zone of influence of the pumping. The procedures to be used to perform the aquifer tests are provided in the flnal SSP as SOP 4.3. In addition to the constant rate pump test, a recovery test will be conducted after each aquifer test to monitor the groundwater elevations recovery to ambient conditions. The procedures to be used to perform the recovery tests are also included in SOP 4.3.

The data collected during the aquifer and recovery tests will be used to quantify the vertical and horizontal groundwater flux of tested hydrogeologic units. Commonly accepted pump test analysis software will be used to help identify the theoretical model/method to quantify the hydraulic properties.

Background Water level Locations

As discussed above, the following wells will be monitored for approxiniately 5 to 10 days prior to any aquifer testing activities to establish background trends in the hydrogeologic regime at the BFOU. The following wells will be monitored:

• Uppermost Water Table: • HBF-5, HMW-301, HMW-701, HMW-702, HMW-703, HMW:704

• 1075 Sand: • HOW-IC, HOW-ID, H0W-2C, H0W-2D, H0W-3C, H0W-3D,

HBF-15D, HMW-204, HMW-305 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, HOW-IA, HOW-IB, H0W-2A, HOW-2B, H0W-3A, H0W-3B, HMW-203

Aquifer Tests

As discussed above, three aquifer tests will be conducted targeting the 1050 sand zone. These tests are described below:

Test 1 - Test 1 will be conducted in the northwest corner of the BFOU (See Figure 27). The pumping well (HPW-1) will be installed to a depth of approximately 70 ft., bgs targeting the 1050 sand encountered in monitoring well HMW-103. Two additional 1050 sand observation wells (HOW-IA & HOW-IB) will be installed north of the pumping well at distances of approximately 25 ft. and 100 ft., respectively. Two 1075 sand observation wells (HOW-IC & HOW-ID) will be installed approximately 10 ft. and 20 ft. north of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: • HBF-4, HBF-5, HBF-5B, HBF-IOS, HBF-15S, HMW-301

• 1075 Sand: • HOW-IC, HOW-ID, HBF-IOD, HBF-15D, HBF-16, HMW-104,

BF-23D, HMW-305, HMW-204 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, HOW-IA, HOW-IB, HMW-102, HMW-103, HMW-203, HMW-304, BF-17

Test 2 - Test 2 will be conducted in the south-central portion of the BFOU (See Figure 28). The pumping well (HPW-2) will be installed to a depth of approximately 60 ft. bgs targeting the 1050 sand. Two additional 1050 sand observation wells (H0W-2A & H0W-2B) will be installed east of the pumping well at distances of approximately 25 ft. and 100 ft., respectively. Two 1075 sand observation wells (H0W-2C & H0W-2D) will be installed approximately 10 ft. and 20 ft. east of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: • HBF-5, HBF-IOS, HBF-14, HMW-301,HMW-703, HMW-704

• 1075 Sand: • H0W-2C, H0W-2D, HBF-6, HBF-IOD, HBF-13, HBF-19S,

HMW-204, HMW-305 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, H0W-2A, H0W-2B, HMW-102, HMW-103, HMW-203, HMW-304, BF-17, BF-20S

Test 3 - Test 3 will be conducted in the northeast corner of the BFOU (See Figure 29). The pumping well (HPW-3) will be Installed to a depth of approximately 60 ft. bgs targeting the 1050 sand. Two additional 1050 sand observation wells (H0W-3A & H0W-3B) will be Installed south of the pumping well at distances of approximately 25 and 100 ft., respectively. Two 1075 sand observation wells (H0W-3C & H0W-3D) will be installed approximately 10 ft and 20 ft. south of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: • HMW-301, HMW-505, HCW-1, HMW-701, HMW-702, HMW-704

• 1075 Sand: • HMW-204,,HMW-504, HMW-604, BF-22S, HBF-6, HBF-2, HOW-

3C, H0W-3D • 1050 Sand:

• HPW-1, HPW-2, HPW-3, H0W-3A, H0W-3B, BF-17, BF-20S, HMW-102, HMW-103, HMW-203, HMW-304

3.2.7 Hydrology - Water Balance

To further understand the hydrology at the BFOU, a water balance evaluation will be undertaken as part of Field Effort 2. The existing on-site weather station will continue to be used to monitor precipitation at the Site, and surface water flow will be calculated in the drainage ways at the Site. These data will be used to estimate groundwater recharge, groundwater discharge, surface water runoff and evapotransplration. These data along with groundwater flux calculations, will allow for an estimation of Site water balance. The calculation of surface water drainage will include the measurements of drainage ways and the installation of four gauging stations in the un-named tributary east of the BFOU to calculate surface water flow. One of the four gauging stations will include the installation of a weir at the end of the pipe located adjacent to the'seep to allow for direct measurement of flow of the un-named tributary at this location. The other gauging stations will consist of the installation of a surveyed stream gauge to record surface water levels along the un-named tributary. These data will be augmented with hydrogeologic data, and a water balance will be calculated for the Site.

3.3 Surface Water Investigation Work Scope

3.3.1 Data Gap

Based on the results of the surface water sampling investigation, the decision criteria regarding surface water sampling have been met. Accordingly, additional downstream surface water sampling is unnecessary. However, estimated concentrations of 1,1-dichloroethane in stream sediments appear to exceed USEPA Region 5, RCRA Ecological Screening Criteria.

3.3.2 Field Effort 2 Scope of Work

Because of the uncertainty associated with the quantification and identification of this compound, re-collection of three stream sediment samples from the existing locations will be completed to confirm results of the initial analyses detailed above. The procedures that will be used to collect and analyze these samples are those provided in the final SSP, including: • 4.1 Manual Water Level Measurement Procedure; • 5.2 Groundwater Sampling; • 9.0 Waste Characterization - Investigation Derived Wastes; and • 8.0 Equipment Decontamination.


3.4 Waste Cell Characterization Work Scope

3.4.1 Data Gap

As discussed in section 2.1.2, above, the deep test pit at waste cell D-7 collapsed after reaching the bottom of the waste cell. Therefore, no sidewall or bottom samples were collected during excavation activities. However prior to backfilling the excavation, a marker was placed into the pit to document the location of the test pit. A Geoprobe soil boring was installed at this location to collect sidewall and bottom samples. A sidewall sample was not collected during these sampling activities, because of the uncertainly associated with the collection of a potentially disturbed sample (due to the collapse of the excavation in this area). However, to meet the requirements of the SSP, a sidewall soil sample will be collected at this location, during Field Event 2.


The procedures that will be used to collect and analyze this sidewall sample are those provided in the final SSP, including:

2.2 Drilling Techniques 2.3 Soil Borings 2.5 Soil Classification 5.1 Soil Sample Collection For Laboratory Analysis 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.


G:\28703\Work Plan Addendum&Data ReportNworkplan addendumNTremonl BFOU WPA.083004.doc DSN: 28703.019 082604 0802

TABLE 18 BARREL FILL OPERABLE UNIT

TREMONT CITY, OHIO SUMMARY OF FIELD AND LABORATORY PROCEDURES

Task

Test Pit / Waste Cell Sampling

Groundwater Investigation

Seep/ Sediment

Investigation

Activity Description

Test Pit Sidewall Sample (D-7)

BFOU Monitoring Wells

Seep Investigation

Seep Investigation

Media Collection Method

Geoprobe

Ultra/Low flow sampling

Manual collection

Manual collection

Sample Matrix

Soil

Ground water

Sediment

Surface Water

Field Parameters

FID VOC Screen

FID VOC Screen, pH. temp, cond.,

turbidity, DO, ORP

FID VOC Screen

pH, temp, cond., turbidity, DO, flow

Laboratory Parameters*

TAL/TCL

TALTTCL

TALTTCL

TAL/TCL and general chemistry (2)

Investigative Samples

1

To Be Determined

3

1

Equipment Rinseate Blanks

1/10

1/10

1/10

1/10

Field Duplicates

1/10

1/10

1/10

1/10

Matrix Spikes/ Matrix Spike Duplicates

1/10

1/10

1/10

1/10

Comments

No filtered metals will be collected. Two rounds of sampling are proposed.

Two rounds of sampling are proposed.

Haley Aldrich, Inc.

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^HPW-1 — PUMPING WELL LOCATIONS

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SCALE IN FEET

TREMONT CFTY U^NDRLL BARREL RLL OPEHABLE UNIT TREMONT CtTY, OH

AQUIFER TEST 1 LOCATION AND MONITORING WELL NETWORK

SCALE: A5 SHOWN AUGUST 2004

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PUMPING WELL LOCATIONS

WATER TABLE WELLS

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DURING FIELD EFFORT 2.

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PUMPING WELL LOCATIONS

WATER TABLE WELLS

1075 SAND WELLS

1050 SAND WELLS

300

SCALE

TREMOMT CITY LANDRLL BARREL nLL OPERABLE UNIT TREMONT CFTY. OH


SCALE: AS SHOWN AUGUST 2004

FIGURE 29

3.0 WORK PLAN ADDENDUM

Activities to be completed during Field Effort 2 of the Remedial Investigation at the Tremont City Landfill BFOU are detailed below. These activities are based on results of Field Effort 1 activities as discussed in previous sections. Methods and procedures to complete the Field Effort 2 scope of work are described in the Final SSP (Haley & Aldrich, July 2003) and are consistent with the Administrative Order by Consent (AOC) and related Scope of Work (SOW), entered and agreed to by the Performing Respondents on 3 October 2002

3.1 Work Plan Addendum - Field Effort 2

Based on the results of RI Field Effort 1, several data gaps were identified that will require additional assessment as a part of Field Effort 2. These data gaps are summarized below, followed by a summary of the Field Effort 2 Work Plan.

3.L1 Data Gap Summary

These data gaps include:

The downgradient extent of COCs in groundwater exceeding screening criteria in shallow monitoring well HMW-301 needs to be determined. The water table unit monitoring network needs to be enhanced downgradient (east) of the BFOU. The relationship between shallow groundwater and the unnamed tributary needs to be evaluated. An evaluation of background concentrations of arsenic, antimony and manganese in groundwater needs to be completed. An evaluation of BHC and alpha chlordane in groundwater needs to be completed. The gradient and flow direction in the deep sand and gravel unit on the western portion of the barrel fill needs to be ascertained. Vertical and horizontal groundwater flow (flux) and the vertical hydraulic conductivity of selected hydrosratigraphic units beneath the site need to be determined. The presence and magnitude of 1,1-dichloroethane concentrations detected in stream sediment samples needs to be verified. No sidewall sample was collected from Test Pit D-7 during Field Effort 1.

3.L2 Field Effort 2 Work Plan Summary

In order to fill the above listed data gaps, several additional task items are proposed for Field Effort 2. These include: • One additional shallow, water table unit well will be installed downgradient of HMW-

301 to define the horizontal extent of COCs exceeding screening criteria. • Three additional shallow, water table unit wells will be installed downgradient of the

BFOU to enhance the water table unit monitoring network. • Surface water gauging will be completed along the unnamed tributary located east of

the BFOU to define the relationship between shallow groundwater and surface water in this area.

• Two additional rounds of groundwater sampling will be completed to evaluate groundwater quality at the site. Samples from each well will be analyzed for TAL/TCL

constituents. Statistical evaluation of total metals analyses will be used to define background concentrations for those metals exceeded screening criteria.

• Three piezometers will be installed into the deep sand and gravel unit to aid in defining the hydrogeologic relationship between the BFOU and landfill and to determine the groundwater gradient in this unit on the western portion of the BFOU.

• Additional groundwater level monitoring will be performed in wells installed in each hydrogeologic unit to better define groundwater flow directions, gradients, and the variability associated with each unit.

• Aquifer (pump) testing will be completed to characterize vertical groundwater flux and other hydrogeologic characteristics of the hydrogeologic units beneath the site.

• Additional sediment samples will be collected from the unnamed tributary, in the vicinity of SE-02, to confirm the presence of estimated concentrations of 1,1-dichloroethane detected.

• One "side wall" sample will be collected, utilizing drilling techniques, from adjacent to waste cell D-7 during Field Effort 2, to meet the requirements of the SSP.

All activities discussed herein will be completed following procedures outlined in the Final RI/FS Support Sampling Plan (SSP; Haley & Aldrich, Inc., July 2003) except those activities with procedures not included in the SSP. Procedures for those activities not addressed by the SSP are discussed in greater detail in the following sections.

3.2 Groundwater Investigation Work Scope

As detailed in the SSP and summarized in the Data Report, the primary decision for the groundwater investigation was to determine whether or not on-site groundwater quality met the federal drinking water standards published as the Maximum Contaminant Levels (MCLs) by the USEPA Office of Water, or if MCLs do not exist, other applicable screening criteria. A secondary decision for the groundwater investigation was to determine whether or not off-site impacts currently exist or are likely to exist in the future from the observations conducted at on-site groundwater monitoring wells. The decision rules for the groundwater investigation are:

• If the concentrations of TCL organics and TAL inorganics detected in groundwater samples collected from monitoring wells are less than their respective MCLs (or if MCLs do not exist, other applicable screening criteria) then, the vertical and horizontal extent of impacted groundwater has been defined;

• Based on hydrogeologic testing to be completed during the initial field investigation and knowledge of potential future migration pathways, if the concentrations of TCL organics and TAL inorganics detected in groundwater samples collected from monitoring wells are less than their respective MCLs (or if MCLs do not exist, other applicable screening criteria), then the potential for vertical and horizontal extent of impacted groundwater has been defined;

• For TAL metals, if concentrations exceed MCLs (or if MCLs do not exist, other applicable screening criteria) and are less than background, then the extent of impacted groundwater from TAL metals has been delineated.

Based on the data presented above, it appears that these decision criteria have not been met in several specific instances. In addition, groundwater flow has not been ascertained in the deep sand and gravel on the western portion of the site and the water table unit monitoring network is insufficient on the eastem portion of the BFOU. Therefore, additional groundwater investigation activities to obtain information to meet these criteria are proposed, as described below.

3.2.1 Groundwater Quality - Volatile Organic Compounds

A. Data Gap

Groundwater samples collected from the water table well HMW-301 contained concentrations of several constituents in excess of screening criteria. Samples from wells located in the same well cluster, but screened in lower units (1075 sand, 1050 sand and deep sand and gravel units) contained no concentrations of any COC in excess of screening criteria. Evaluation of these data, based on review of the decision criteria presented above indicates that while the vertical extent of these compounds has been determined, the horizontal, downgradient extent has not.


In order to fill the above data gap, one additional monitoring well, installed and screened in the water table unit, will be installed downgradient of HMW-301, as depicted in Figure 26. The procedures that will be used to drill, install, monitor, and sample this well are those provided in the final SSP, including:

2.2 Drilling Techniques/Background Information; 2.3 Soil Borings; 2.5 Soil Classification; 3.1 Well Construction Materials; 3.2 Procedures for Overburden Monitoring Well Installation; 3.3 Well Development; 4.1 Manual Water Level Measurement Procedure; 5.2 Groundwater Sampling; 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.

3.2.2 Groundwater Quality - Pesticides

A. Data Gaps

• Beta-BHC: Groundwater samples collected from the water table well HBF-5B contained a concentration of a pesticide, beta-BHC (0.1 ug/1), in excess of screening criteria. Samples from all other wells constructed in the water table unit, as well as all other hydrogeologic units identified at the site, contained no concentrations of this compound. Further, based on review of groundwater flow directions in the water table unit, this well appears to be upgradient to the BFOU. Based on the potential for an agricultural source for this pesticide compound, the upgradient position of the well, and the singular detection, it appears that this compound is likely related to upgradient, off-

site issues. Therefore, additional investigative activities related to this detection, except re-sampling of all wells to determine the reproducibility of this occurrence, are not warranted.

• Alpha Chlordane: Groundwater samples collected from the 1075 Sand well HBW-204 contained an estimated concentration of a pesticide, alpha chlordane (0.17 J ug/1), in excess of screening criteria. Samples from all other wells constructed in the water table unit, as well as all other hydrogeologic units identifled at the site, contained no concentrations of this compound. Based on the potential for an agricultural source for this pesticide compound, the estimated-quantification of the reported concentration, the upgradient position of the well, and the singular detection, it appears that this compound is likely related to upgradient, off-site issues. Therefore, additional investigative activities related to this detection, except re-sampling of all wells to determine the accuracy of the estimated concentration and reproducibility of this occurrence, are not warranted.


In order to fill the above data gap, several rounds of groundwater level gauging will be completed, with the resulting data used to define groundwater flow direction and upgradient monitoring well locations. This infonnation will be used to define potential sources.

Two additional rounds of groundwater sampling and analysis (for TAL/TCL compounds) will also be completed. Results of these analyses will be used to determine if these two pesticides, in fact, are present in groundwater beneath the site.


3.2.3 Groundwater Quality - Metals

A. Data Gaps

Arsenic, antimony and manganese were detected in several wells at concentrations exceeding screening criteria. Each of these compounds are naturally occurring and are historically present, at varying concentrations, in many areas within Ohio. Accordingly, comparison of these compounds to background concentrations is necessary to determine if these compounds are related to past site activities or are simply present at naturally occurring levels. Each of these compounds were detected during RI Field Effort 1 activities as described below:

• Arsenic: Arsenic was detected in groundwater samples collected from 48 monitoring wells during this sampling event. Seventeen wells had concentrations in excess of the screening criterion (10 ug/1), the highest concentration of which was detected in monitoring well BF-23D (26.4 ug/1). These wells were located both upgradient and downgradient of the BFOU and were screened within all intervals. Further, arsenic was the only compound detected in any soil at a concentration exceeding the screening criterion. This concentration was detected in a background surface soil sample (BK-5).

• Antimony: Antimony was detected in samples from two monitoring wells (BF-19S and BF-23DD) at concentrations exceeding screening criteria. These wells are constructed in different hydrogeologic units (1075 sand and 1050 sand, respectively) and are located at some distance from each other, with both potentially being situated upgradient of the BFOU.

• Manganese: Manganese was detected in samples from two monitoring wells (HMW-301 and BF-22S) at concentrations exceeding screening criteria. These wells are constructed in different hydrogeologic units (water table and 1075 sand, respectively) and are located at some distance from each other (HMW-310 is near the southem portion of the BFOU, while BF-22S is north of the BFOU).


In order to fill the above data gap, several rounds of groundwater level gauging will be completed, with the resulting data used to define groundwater flow direction and upgradient monitoring well locations. Two additional rounds of additional groundwater sampling and analysis (for TAL/TCL compounds) will also be completed. Results of these analyses will be used to determine the concentrations of these metals present in groundwater beneath the site.

After the above activities are completed, a statistical evaluation of laboratory data will be completed to determine if concentrations of these metals are within expected background concentration ranges. Statistical methods to be used will be based on the characteristics of the data collected (e.g. parametric, non-parametric, etc.).

The procedures that will be used to monitor and sample this well are those provided in the final SSP, including:

• 4.1 Manual Water Level Measurement Procedure; • 5.2 Groundwater Sampling; • 9.0 Waste Characterization - Investigation Derived Wastes; and • 8.0 Equipment Decontamination.


3.2.4 Water Table Unit Monitoring Well Network Enhancement

A. Data Gap

Evaluation of groundwater elevation data from wells screened in the water table unit (Figure 26) indicates that the current monitoring network is insufficient for long term monitoring of groundwater flow and quality downgradient (east) of the BFOU. During Field Effort 1, one monitoring well (FIMW-301) located downgradient of the BFOU was sampled. A second well (HCW-1) was dry during this sampling event, but based on recent monitoring, now contains several feet of water. Additional wells are necessary to better define long-term groundwater fiow and quality in this area.


To fill the data gap described above, three shallow monitoring wells, installed and screened in the water table unit, are proposed. These wells will be installed as follows: • One well will be installed midway between HMW-301 and HBF-14; • One well will be installed midway between HCW-1 and HMW-301; and • One well will be installed north of HCW-1, along the northem boundary of the BFOU.

The proposed locations of these monitoring wells are depicted on Figure 26. The procedures that will be used to drill, install, and monitor these wells are those provided in the final SSP, including:

2.2 Drilling Techniques/Background Information; 2.3 Soil Borings; 2.5 Soil Classification; ^ 3.1 Well Construction Materials; 3.2 Procedures for Overburden Monitoring Well Installation; 4.1 Manual Water Level Measurement Procedure; 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.

3.2.5 Groundwater Flow in Deep Sand and Gravel Unit

A. Data Gap

Evaluation of groundwater elevation data from wells screened in the deep sand and gravel unit indicates that additional investigation is needed to better define the fiow direction in the westem portion of the deep sand and gravel unit. Existing monitoring wells screened in this unit indicate a head difference of 0.02 feet across the entire BFOU. A more significant head difference is needed to define the groundwater flow direction and to determine the hydrogeologic effects of the Tremont City Landfill on this unit.


To fill the data gap described above, three deep piezometers, installed and screened in the deep sand and gravel, are proposed. These piezometers will be installed as follows: one north of the BFOU, one west of the BFOU, and one south of the BFOU, each within the westem portion of the sand and gravel unit (west of the apparent flow boundary). The proposed locations of these piezometers are depicted on Figure 26. The procedures that will be used to drill, install, and monitor these piezometers are those provided in the final SSP, including:


3.2.6 Hydrogeology - Vertical Flux

A. Data Gap

Although a significant amount of data has been collected regarding the hydrogeology of the BFOU, little information has been obtained on the vertical and horizontal groundwater flux. These data will be crucial in defining future risk scenarios for the BFOU area.


To fill this data gap, three aquifer tests will be completed at the BFOU. The tests will be conducted at locations depicted in Figures 27 -29. In general, the aquifer tests will consist of low volume long duration tests, pumping from the 1050 sand zone. This type of test is based on:

• Reviews of historic aquifer tests conducted near the BFOU; and • Field Effort 1, including in-situ hydraulic conductivity test results, permeability test

results from shelby tube samples, well development observations, groundwater elevation data and stratigraphic information; and

The results of the review of historic pump tests and Field Effort 1 hydrogeologic data indicate that a constant pumping rate of approximately 0.1 to 0.2 gallons per minute (gpm) over a time period of approximately five days at the proposed aquifer test locations should be adequate to

quantify horizontal hydraulic conductivity of the 1050 sand zone and the vertical hydraulic conductivity of the tills overlying the 1050 sand zone. The locations of the tests were chosen based on the stratigraphy anticipated to be encountered and to provide aerial coverage of the BFOU. Specifically, it is anticipated that the 1050 sand zones encountered at each of these locations will have the potential to sustain the pumping rate and duration discussed above. Please note that because of variability in the stratigraphy at the BFOU (i.e. variable thickness and location of sand units) the possibility exists that these proposed locations will not be suitable to obtain the design pumping rates and duration needed to quantify groundwater velocity and flux. In the event that initial drilling activities indicate the location is not suitable, altemate locations will be used.

At each of these locations, a pumping well will be installed in the targeted 1050 sand zone using procedures for well installation activities described in the SSP (procedures listed below). Pumping well design will differ slightly from the design of monitoring wells installed during Field Effort 1 with the intent to maximize the specific capacity and efficiency of the wells. The pumping wells will be installed in 8-inch diameter borings and consist of a 4-inch diameter, 0.010 slot stainless steel well screens. The screen intervals will be designed to match the thickness of the targeted sand zone. The sand pack will consist of washed silica sand of the appropriate size for the screen. In addition to the pumping well, observation wells will be used in conjunction with existing monitoring wells to monitor groundwater elevations in different hydrogeologic units adjacent to the pumping well at each aquifer test location. The observation wells will target the 1050 sand zone and the 1075 sand zone. In general, the 1050 sand zone will be monitored at distances of 25 ft. and 100 ft. away from the pumping well. Approximately two 1075 sand zone observation wells will be installed 10 and 20 ft. away from the pumping well. Details of pumping well and observation wells are detailed below for each test. The procedures that will be used to drill, install, and monitor these observation wells are those provided in the final SSP, including:


After all pumping well and observation well installations and prior to any aquifer testing (pumping) activities, continuous water levels will be measured for approximately 5 to 10 days in the newly installed pumping wells and observation wells and in selected existing monitoring wells (approximately 25 wells total) using data loggers. These data will be used to establish background trends in the hydrogeologic regime. In addition, water levels in all existing BFOU monitoring wells will be measured at least twice during this time period.

Prior to beginning individual aquifer tests, data loggers will be left in the pumping well and observation wells and moved to selected monitoring wells in the anticipated zone of influence of the pumping. The procedures to be used to perform the aquifer tests are provided in the flnal

SSP as SOP 4.3. In addition to the constant rate pump test, a recovery test will be conducted after each aquifer test to monitor the groundwater elevations recovery to ambient conditions. The procedures to be used to perform the recovery tests are also included in SOP 4.3.

The data collected during the aquifer and recovery tests will be used to quantify the vertical and horizontal groundwater flux of tested hydrogeologic units. Commonly accepted pump test analysis software will be used to help identify the theoretical model/method to quantify the hydraulic properties.

Background Water level Locations

As discussed above, the following wells will be monitored for approximately 5 to 10 days prior to any aquifer testing activities to establish background trends in the hydrogeologic regime at the BFOU. The following wells will be monitored:

• Uppermost Water Table: • HBF-5, HMW-301, HMW-701, HMW-702, HMW-703, HMW-704

• 1075 Sand: • HOW-IC, HOW-ID, HOW-2C, HOW-2D, HOW-3C, HOW-3D,

HBF-15D, HMW-204, HMW-305 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, HOW-IA, HOW-IB, HOW-2A, H0W-2B, H0W-3A, HOW-3B, HMW-203

Aquifer Tests

As discussed above, three aquifer tests will be conducted targeting the 1050 sand zone. These tests are described below:

Test 1 - Test 1 will be conducted in the northwest comer of the BFOU (See Figure 27). The pumping well (HPW-1) will be installed to a depth of approximately 70 ft., bgs targeting the 1050 sand encountered in monitoring well HMW-103. Two additional 1050 sand observation wells (HOW-IA & HOW-IB) will be installed north of the pumping well at distances of approximately 25 ft. and 100 ft., respectively. Two 1075 sand observation wells (HOW-IC & HOW-ID) will be installed approximately 10 ft. and 20 ft. north of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: • HBF-4, HBF-5, HBF-5B, HBF-IOS, HBF-15S, HMW-301

• 1075 Sand: • HOW-IC, HOW-ID, HBF-IOD, HBF-15D, HBF-16, HMW-104, BF-

23D, HMW-305, HMW-204 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, HOW-IA, HOW-IB, HMW-102, HMW-103, HMW-203, HMW-304, BF-17

Test 2 - Test 2 will be conducted in the south-central portion of the BFOU (See Figure 28). The pumping well (HPW-2) will be installed to a depth of approximately 60 ft. bgs targeting the 1050 sand. Two additional 1050 sand observation wells (H0W-2A & H0W-2B) will be installed east of the pumping well at distances of approximately 25 ft. and 100 ft., respectively. Two 1075 sand observation wells (HOW-2C & H0W-2D) will be installed approximately 10 ft. and 20 ft. east of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: - HBF-5, HBF-IOS, HBF-14, HMW-301,HMW-703, HMW-704

• 1075 Sand: • HOW-2C, HOW-2D, HBF-6, HBF-1OD, HBF-13, HBF-19S, HMW-

204, HMW-305 • 1050 Sand:

• HPW-1, HPW-2, HPW-3, H0W-2A, HOW-2B, HMW-102, HMW-103, FIMW-203, HMW-304, BF-17, BF-20S

Test 3 - Test 3 will be conducted in the northeast comer of the BFOU (See Figure 29). The pumping well (hIPW-3) will be installed to a depth of approximately 60 ft. bgs targeting the 1050 sand. Two additional 1050 sand observation wells (HOW-3A & HOW-3B) will be installed south of the pumping well at distances of approximately 25 and 100 ft., respectively. Two 1075 sand observation wells (HOW-3C & HOW-3D) will be installed approximately 10 ft and 20 ft. south of the pumping well. Water levels in the following 25 wells will be monitored using data loggers during the duration of the test:

• Uppermost Water Table: - HMW-301, HMW-505, HCW-1, HMW-701, HMW-702, HMW-704

• 1075 Sand: • HMW-204, HMW-504, HKlW-604, BF-22S, HBF-6, HBF-2, HOW-

3C, HOW-3D • 1050 Sand:

• HPW-l,HPW-2, HPW-3, HOW-3A,HOW-3B, BF-17, BF-20S, HMW-102, HMW-103, HMW-203, HMW-304

3.2.7 Hydrology - Water Balance

To further understand the hydrology at the BFOU, a water balance evaluation will be undertaken as part of Field Effort 2. The existing on-site weather station will continue to be used to monitor precipitation at the Site, and surface water flow will be calculated in the drainage ways at the Site. These data will be used to estimate groundwater recharge, groundwater discharge, surface water runoff and evapotransplration. These data along with groundwater flux calculations, will allow for an estimation of Site water balance. The calculation of surface water drainage will include the measurements of drainage ways and the installation of four gauging stations in the un-named tributary east of the BFOU to calculate surface water flow. One of the four gauging stations will include the installation of a weir at the end of the pipe located adjacent to the seep to allow for direct measurement of flow of the un-named tributary at this location. The other gauging stations will consist of the installation

of a surveyed stream gauge to record surface water levels along the un-named tributary. These data will be augmented with hydrogeologic data, and a water balance will be calculated for the Site.

3.3 Surface Water Investigation Work Scope

3.3.1 Data Gap

Based on the results of the surface water sampling investigation, the decision criteria regarding surface water sampling have been met. Accordingly, additional downstream surface water sampling is unnecessary. However, estimated concentrations of 1,1-dichloroethane in stream sediments appear to exceed USEPA Region 5, RCRA Ecological Screening Criteria.


Because of the uncertainty associated with the quantification and identification of this compound, re-collection of three stream sediment samples from the existing locations will be completed to confirm results of the initial analyses detailed above. The procedures that will be used to collect and analyze these samples are those provided in the final SSP, including: • 4.1 Manual Water Level Measurement Procedure; • 5.2 Groundwater Sampling; • 9.0 Waste Characterization - Investigation Derived Wastes; and • 8.0 Equipment Decontamination.


3.4 Waste Cell Characterization Work Scope

3.4.1 Data Gap

As discussed in section 2.1.2, above, the deep test pit at waste cell D-7 collapsed after reaching the bottom of the waste cell. Therefore, no sidewall or bottom samples were collected during excavation activities. However prior to backfilling the excavation, a marker was placed into the pit to document the location of the test pit. A Geoprobe soil boring was installed at this location to collect sidewall and bottom samples. A sidewall sample was not collected during these sampling activities, because of the uncertainly associated with the collection of a potentially disturbed sample (due to the collapse of the excavation in this area). However, to meet the requirements of the SSP, a sidewall soil sample will be collected at this location, during Field Event 2.


The procedures that will be used to collect and analyze this sidewall sample are those provided in the final SSP, including:

2.2 Drilling Techniques 2.3 Soil Borings 2.5 Soil Classification 5.1 Soil Sample Collection For Laboratory Analysis 9.0 Waste Characterization - Investigation Derived Wastes; and 8.0 Equipment Decontamination.

Planned analyses are summarized in Table 18.* Laboratory procedures that will be used to analyze each of the samples collected are provided in Appendix B of the Final QAPP (Haley & Aldrich, July 2003).

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