This summary was updated November 28, 2001
After removing 121 tons of capacitors, 36,157 tons of contaminated dirt and treating 119,888 gallons of
water, work at Bennett's Quarry was completed in November 1999. Viacom and the EPA have been monitoring the site. The EPA has received and commented on Viacom's Groundwater Monitoring Plan, and several Groundwater Monitoring Reports have been issued.
Tom Alcamo, EPA Project Manager, has has implemented continuous flow measurements for Middle Spring & Mound Spring, Stouts Creek, as well as quarterly PCB sampling , storm event sampling, and dye trace studies in order to better understand the situation there. Recent sampling data indicates that the Springs continuously release PCBs, and that there is no PCB spike due to storm events. At the latest CIC meeting, EPA presented a chart derived from the storm event of July 4, 2001, showing small spikes in PCB levels at Middle Springs only. This fall, Viacom purged and removed sediment for Monitoring Wells 6I and 6D. They found PCB oil in Monitoring Well 5, and it was bailed number of times. Viacom and EPA are discussing how to address the PCB problem with MW 5, and a piezometer was installed in Grid H7.
There have been changes in flow rates and PCB concentrations in water coming out of the springs scattered around the site. Middle Spring has increased flow and PCB concentration, with PCBs from 1.3 to 10 ppb. Mound Spring measured from 0.46 to 2.7 ppb.
It has been shown to have a slow flow response, and a small variation in conductivity during storms.
It is problematic that Stout's Creek has higher concentrations of PCBs downstream than it does coming out of the dump area. This could indicate that PCBs are migrating through the karst to springs farther downstream, though there may be other scenarios as well.
The EPA is "far from done" with Stout's Creek according to the EPA's Tom Alcamo. He is worried that the new highway interchange could affect the groundwater level, and will consider pumping the surrounding quarries and/or creating a collection trench to divert water. They are now monitoring the water levels in the Icebox and Wedge Quarries, as well as Stout's Creek.
The EPA's planned Groundwater Investigation Plan will:
- Define site hydrology and recharge area,
- Define the relationship between groundwater
elevations, water levels in quarry pits and spring flows
- Study the effect of the highway construction.
- Estimate mass loading to Stout's Creek.
Field Oversight Summaries are being done for EPA by Tetra Tech EM.
Viacom has expressed reluctance to do much of this work, but the EPA is ready to go ahead and let the matter be decided in the courts.
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