From: KENT Mavis D
Sent: Wed Jul 21 16:15:09 2010
To: 'Sarah Prowell'
Cc: Chris Kimmel
Subject: RE: TSA August 2010 Vertical Profile Diffusion Bag Sampling - EW-16, MW-26dg, MW-19ds
Importance: Normal
Sarah, I have reviewed the attached map and table and your description below. I have no comment on your proposed placement of diffusion bags so approve their use as proposed. I assume that as a one-time event you will also sample these wells in a regular purge method. I am now curious and sorry I won’t be here to see the results. Diffusion bag sampling has really be useful to the sites both for cost savings as well as to pinpoint problems.
From: Sarah Prowell [mailto:sprowell@ix.netcom.com]
Sent: Wednesday, July 21, 2010 9:18 AM
To: KENT Mavis D
Cc: Chris Kimmel
Subject: TSA August 2010 Vertical Profile Diffusion Bag Sampling - EW-16, MW-26dg, MW-19ds
Mavis,
Please find attached a table summarizing diffusion bag depth settings proposed for TSA wells EW-16, MW-26dg, and MW-19ds, for which we seek your approval to install and sample in August, as part of the annual sampling round. (Well location map attached.) At this time, the vertical profile sampling is proposed as a one time event.
The EW-16 and MW-26ds diffusion bag installations are proposed for the purpose of evaluating TCE vertical distribution in the eastern remediation area, where TCE persists, but at low concentrations near the cleanup level. The vertically profiled sample findings will be evaluated against the original conceptual model of downward TCE migration from the vicinity of Upper TSA well MW-26ds (now decommissioned) to the Lower TSA, as detected in MW-26dg and pilot shutdown well EW-16.
The MW-19ds vertically profiled diffusion bag installations are proposed for the purpose of evaluating whether TCE is prevalent at levels above the MCL throughout the screened interval or only within limited intervals. (TCE has been previously detected at concentrations near the clean up level.)
Sincerely, Sarah
Sarah Prowell, R.G.
Prowell Environmental, Inc.
2216 SW Sunset Blvd.
Portland, Oregon 97239
Phone: 503/452-0972
Fax: 503/452-1427