Post-Excavation Groundwater Monitoring Results for Sept. 18, 2001
Bennett's Dump, Monroe County, Indiana

Viacom
December 11, 2001

This letter summarizes the results of the September 18 and 21, 2001 Groundwater sampling events performed by Viacom Inc. at the Bennett's Dump site. In accordance with post-excavation interim monitoring requirements outlined in the Bennett's Dump Statement of Work (SOW), Groundwater sampling was performed at the following locations: Monitoring Well 3, Monitoring Well 61 and Monitoring Well 6D. The general locations of these sampling points are shown on Figure I (attached).

As described in Viacom's August 21, 2001 letter to the parties, additional procedures were followed at MW6I and MW6D. These wells were vigorously purged of three well volumes on September 4, 2001. After each well volume was purged, turbidity was measured. The purging was performed using an electric jet pump in a manner similar to the procedure used at Winston Thomas in July and August, 2001. After purging, and prior to sampling, aluminum sampling tubing was installed in MW 61 and MW 6D, with the intake ends positioned at the midpoint of the well screen sections.

Low-flow rate sampling was performed at wells 61 and 6D on September 18, 2001. At each well, the initial water level was measured and monitored while a peristaltic pump removed well water at a very low rate, 30-50 mL/minute. Drawdown of the water surface was minimized and the field parameters of conductivity, temperature and turbidity were monitored. For each well, the MasterFlex peristaltic sampling pump was adjusted to the lowest possible speed in an attempt to avoid drawdown of the water surface. However, inflow or recharge of Groundwater into each well was not sufficient to prevent drawdown, even at this very low pumping rate. At both wells the first three conductivity readings indicated stability, and the turbidity values began at 1.05 ntu and decreased slightly. Samples were collected in 1 L amber glass bottles. For quality assurance purposes a duplicate sample and a field blank were collected.

On September 21, 2001 monitoring well MW 3 was purged and sampled in the usual manner with the dedicated bladder pump installed in the well. The water level in the well was measured and the volume of water in well storage was calculated. MW 3 was purged until one well volume was removed, then continued until field parameters (conductivity, temperature and pH) stabilized to allow representative samples to be obtained.

All samples were labeled and logged onto a chain-of-custody form. The samples were stored on ice and transported in insulated coolers. Custody of the water samples was maintained by Viacom until shipment to the analytical laboratory. Samples were analyzed by Heritage Lab of Indianapolis, Indiana. The samples were analyzed to a detection limit of 0.1 parts per billion (ppb)for all PCB parameters (except Aroclor 122]; detection limit 0.5 ppb) by EPA Method SW-846 8082.

Field measurements, PCB analytical results, and QA/QC results for the September 2001 groundwater monitoring event are presented in Table 1 (attached). Historical PCB results for individual monitoring well locations are presented in Tables 2 through 4.

Copies of the field logs chain-of-custody, laboratory analytical reports and validation statements for the September samples are also attached.

If you have questions regarding this sampling event, or the results reported herein, please call Mike McCann at (812) 334-0030.