SITE INFORMATION AND CORRESPONDENCE

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Ms. Melitta Rorty, P.G. April 18, 2008 Page 2 Recommendation: All Site production wells should be video logged to determine the condition of the casing. The original log for the wells filed with the Department of Water Resources should be located, if possible. The goal of proper well decommissioning is to perforate the well casing at a regional or local vertical zone of low permeability between the surface and the aquifer below, then pressure grout with neat Portland cement to the surface. A local soil boring may be needed to locate the vertical zone best to perforate. 2) Section 3.5 of the Work Plan discusses background soil investigation. Due to the nature and operation of a Town Gas Plant care must be made not sample too close to the facility. Recommendation: Do not obtain background soil samples across the street from the Site. Such samples are likely to have been impacted by the facility (see General Comment above). Regional public parks with similar soil types are better choices. Also, the GSU recommends collecting background PAH samples. 3) Section 3.6.1 describes proposed soil sampling procedures. Soil is to be sampled in three-foot intervals down to 15 feet below grade. Recommendation: Additional samples should also be obtained based on field observations such as staining, odors, photoionization detector results, etceteras. 4) Prior to active soil gas sampling, the GSU recommends the use of passive soil gas sampling (such as Goresorbers) as a first step to locating Site "hot spots." 5) The GSU notes the collection of soils for Environmental Protection Agency Method 82608. No mention is given as to how to minimize the loss of volatile soil compounds. Capped brass soil sample sleeves have been documented to loose as much as 50% of volatile compounds. Recommendation: Collect volatile soil compounds using Encore, methanol or bisulfate preservation, an on-Site laboratory, or similar method. 6) On page 13 of the Work Plan soil gas samples were first to penetrate asphalt using a hydraulic hammer or coring machine. In GSU's experience care must be given to completely remove the asphalt subgrade before attempting active soil gas sampling. Failure to eliminate the asphalt foundation can lead to massive ambient air breakthrough. Recommendation: Use a "cookie cutter" to core out a wide circle (12" or so) of asphalt, then dig out all gravel subgrade foundation until reaching native soil. 7) For risk assessment purposes, list the PAH compounds (2006 results) as Benzo(a)pyrene (B(a)P) equivalent.