Section 1: Introduction

This report documents the Groundwater sampling that was performed at the Winston Thomas site from July 17 to August 3, 2001. Sampling was performed in accordance with the revised Field Sampling Plan (FSP) for Winston Thomas Wells, dated June 25, 2001, and presented in Appendix A.

Section 2: Background

The Winston Thomas site, located in Bloomington, Indiana, is a former municipal wastewater treatment facility. The location of the site within the community is shown on Figure 1. The site is bounded by Gordon Pike to the south and to the north by a channelized intermittent stream or drainage ditch just north of the Interim Storage Facility (ISF) building and the former Tertiary Lagoon. The site is bounded to the east by a National Guard facility and various city and commercial properties along S. Walnut Street and to the west by Clear Creek.

Eleven groundwater monitoring wells were installed at the Winston Thomas site in 1987. The specific details and prior sampling history for these wells is reviewed in the Onsite Ground Water Monitoring Plan, Winston Thomas Facility, Bloomington, Indiana (prepared for Westinghouse Electric Corp. by Blasland & Bouck, May 1989). None ofthese wells has been sampled since 1988.

Remediation activities were performed at the Winston Thomas site between 1996 and 1999. During site remediation, one of the wells, MW2, was abandoned because it was in the way of construction. In discussions among the parties of what to include in the long-term groundwater monitoring plan for the site, a decision had to be made on whether to include the existing monitoring wells. Viacom proposed to perform a round of sampling of the remaining monitoring wells so the resulting data could be used in arriving at a decision.

Because the wells have not been sampled for so long, special care was taken to ensure that the samples were representative of current local aquifer conditions rather than an amalgamation of pre-remedial conditions and well sampling artifacts. Well purging and sampling procedures used for this sampling event are outlined in the revised Field Sampling Plan for Winston Thomas Wells, dated June 25, 2001, and presented as Appendix A.

A brief review of each monitoring well, including the identified water-producing zone, is provided in the Field Sampling Plan in Appendix A. The locations of the monitoring wells at the Winston Thomas site are shown on Figure 2.

Section 3: Sampling Activities

This section describes different purging and sampling procedures for open-hole wells and screened wells. Work was performed in accordance with the approved FSP except as noted herein. All field modifications to this plan were made by Mr. Neill Vaughan, PSARA's onsite geologist, and pre-approved by Mr. Mike McCann, the Viacom field activities supervisor. Samples were collected, handled, maintained, and analyzed in accordance with the Field Sampling Plan for Winston Thomas Groundwater Monitoring Wells, Quality Assurance Project Plan (QAPjP Volume XXVII), dated July 16, 2001.

3.1 INITIAL PURGING

The ten monitoring wells were purged in accordance with the FSP over the period of July 17 to July 20, 2001. The purging procedure began at each well with a measurement of the current depth to bottom and depth to water. These measurements were compared to measurements made in the June 14, 2001, initial survey of the wells. Only minor differences in water levels were observed. A single well volume was calculated for each well using the July 2001 measurements. During purging, turbidity was measured and recorded after the removal of each well volume. Well purging forms are included as Appendix B.

3.1.1 Open Borehole Monitoring Wells

The five open borehole wells were purged with a 4-tn.-diameter submersible pump. The pump was set 5 ft above the bottom of the well. The flow rate during purging ranged from 17 to 21 gallons per minute (gpm) in wells MW-I, MW-4 and MW-8. Wells MW-6 and MW-7 were pumped at about the same rate but could not be pumped continuously without going dry. Purge water was pumped from the monitoring well into a truck-mounted poly tank and then transported to the Neal's Landfill Spring Water Treatment System. Following purging, the pump and discharge tubing were removed from the well. The pump was decontaminated thoroughly, and the discharge tubing was discarded.

The open borehole wells were purged in the following order: MW-6, MW-1, MW-8, MW-4, and MW-7. MW-6 went dry after the first well volume had been withdrawn and was allowed to recover before purging another well volume. This pattern was repeated for each of the five well volumes purged from MW-6. Recovery times between pumping cycles ranged from 54 to 125 minutes. MW-1 sustained continuous pumping of five well volumes without being pumped dry. MW-8 and MW-4 likewise yielded five well volumes in continuous pumping. MW-7, like MW-6, went dry each time it was pumped and required a recovery period that ranged from 57 to 72 minutes between each pumping cycle.

3.1.2 Screened Monitoring Wells

The five screened monitoring wells were purged using a jet pump with the additional goal of removing any sediment that might be present in the well screen or that might be easily pulled into the well through vigorous pumping. Sediment removal during pumping was achieved with the use of a foot valve attached to the end of the pump intake tubing. The foot valve is a one- way valve that assists in priming the pump and served to agitate sediments for removal.

The first step in purging the screened monitor wells was to measure depth to water and depth to bottom in each well. A single well volume was then calculated. The well volume was calculated in two parts: the volume of the water column inside the casing, and the sand-pack volume, which assumed 30 percent porosity as the available water storage volume in the sand pack.

At each well, polyethylene tubing was cut to a length sufficient to reach the bottom, and a foot valve was attached to the down-hole end of the tubing. A jet pump was used to purge the screened monitoring wells. As the well was being purged, the tubing was moved around by hand to help loosen and remove any sediment buildup in the bottom of the well. Purge water was discharged into a truck-mounted poly tank for later disposal at the Neal's Landfill Spring Water Treatment System. Turbidity measurements were made and recorded after each well volume was removed. After purging each well, the tubing was discarded and the pump decontaminated.

The screened wells were purged in the following order: MW-5I, MW-3D, MW-5D, MW-3I, and MW-3S. MW-5I went dry, was allowed to recover, and was pumped again through five cycles of purge and recovery. Recovery times ranged from 42 to 1 12 minutes. MW-3I also went through five purge and recovery cycles, with recovery ranging from 13 to 27 minutes. MW-3D - and MW-3I sustained continuous pumping until five well volumes were purged. MW-3S could not be purged by this method due to an insufficient water column to activate the foot valve. The observed refill or recovery rate also was very slow. Consequently, Viacom field personnel consulted with Mr. Mike McCann of Viacom, Ms. Resa Ramsey of IDEM, and Mr. John Bassett of EarthTech/EPA. All parties agreed that manual purging of MW-3S with a bailer was an acceptable deviation from the FSP in this case. MW-3S was allowed to recover overnight and was successfully purged the next day by hand bailing.

Table 1 summarizes well depth, screen interval (where appropriate), water depth, accumulated sediment thickness, and other parameters for each of the 10 monitoring wells measured on June 14 and June 20, 2001. Table 2 summarizes a few of these same parameters along with turbidity measurements taken during the purging phase from July 17 to July 20, 2001.

3.2 GROUNDWATER SAMPLING

Shortly after the initial purging of the wells, aluminum sampling tubing was installed in each well to the pre-determined sample intake depth specified in Table 1. This tubing was dedicated to the well and left undisturbed until the time of sampling. Although the FSP prescribed the use of Teflon-lined sampling tubing, aluminum tubing was used for reasons of availability and equivalent suitability for the task.

To initiate the low-flow purge and sampling procedure, a short length of flexible silicone tubing was attached to the upper end of the dedicated aluminum tubing and connected to the MasterFlex peristaltic pump. The one exception was open-hole well MW-6, which had a depth to water that exceeded the lifting capacity of the peristaltic pump. For this well, a battery-powered, light-duty centrifugal pump was installed along with dedicated sampling tubing.

The low flow purge procedure involved the removal of groundwater at a sustainable pumping rate (different for each well) and the measurement of conductivity and turbidity until these parameters could be reproduced within prescribed limits (three consecutive measurements within 3% and 10%, respectively). Conductivity and turbidity measurements are recorded on the Low Flow Groundwater Sampling Logs in Appendix C.

Conductivity measurements were within the prescribed 3% variance limit at all wells except MW-3D. The variance at this well was 6.9% over the last three readings, but only 1.9% between the last two readings.

Turbidity measurements generally were not within the prescribed 10% limit for at least three reasons. First and most important, it was observed that repeated measurements of turbidity on the same sample aliquot often exceeded the prescribed 10% limit. Second, all samples tested were clear with no visible evidence of suspended solids. Third, all turbidity measurements were very low, ranging from O to 10.1 ntu and averaging only about 2 ntu, on a meter scale that ranged from O to 1,000 ntu. All these factors were considered in deciding to continue with the sampling program even though the prescribed turbidity criterion could not be met.

Sampling began on July 31 and was completed on August 3, 2001. Sampling parameters, including the pumping rate, conductivity, temperature, and turbidity, are summarized in Table 3. Upon arrival at each well, the sampling team measured depth to water. For the first several minutes, the depth to water was monitored closely as the pumping rate was adjusted in order to arrive at a low-flow pumping rate that minimized drawdown of the water surface and did not exceed 0.5 liter per minute. After a stable pumping rate was achieved, the field parameters were measured and recorded every 5 minutes. Samples were collected after these parameters stabilized. Field sampling forms are included as Appendix C.

Samples were immediately stored in a cooler on ice until transfer to a sample storage refrigerator. The samples were then transported on ice in coolers to Heritage Laboratory in Indianapolis, Indiana. In addition to the normal samples, quality assurance/quality control (QA/QC) samples collected and sent to the lab included a field blank, a duplicate field sample, and an extra sample volume for a matrix spike/matrix spike duplicate (MS/MSD) pair.

Samples submitted to the lab were analyzed for polychlorinated biphenyls (PCBs) in accordance with EPA Method 8082. Table 3 summarizes the analytical results for the 10 monitoring wells sampled. Polychlorinated biphenyls were below the detection limit (BDL) in samples from MW-6, MW-3D, MW-5D, MW-8, and MW-4. Results ranged from 0.13 to 0.41 ~g/1 for the remaining five wells. The laboratory certificates of analysis are included as Appendix D.

SECTON 5: DATA QUALITY VALIDATION

5.1 QUALITY CONTROL SAMPLES

Quality control (QC) samples collected during the sampling phase included a duplicate from one of the monitor wells, a field blank, a Matrix Spike (MS) sample and a Matrix Spike Duplicate. A rinseate blank was not collected since sampling tubing was dedicated to each well and since the sample never came in contact with the peristaltic pump. The only exception was MW-6 where a dedicated centrifical pump was used.

Analytical results for the duplicate sample were in very good agreement, and the result for the single field blank collected was BDL (below detection limit, as shown in Table 3. Recoveries for the MS and MSD samples were within acceptable limits.

Laboratory certificates for these Quality Control samples are included in Appendix D.

5.2 DATA VALIDATION

All laboratory analytical data have undergone Level IV data validation. A validation statement is included in Appendix E.