DERR-2025-003415

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Michael Pecorelli - Midvale chevron Fac. rD 4ooo2l7 tcs
From: Michael pecorelli
To: Trevor L. Atkinson
Date: 9/201201211:02 AM
Subject: Midvale Chevron Fac. ID 4000217 LCSCC: John Menatti
Trevar,
John and I spent an hour or two going over the potential source of the deeper contamination in off-site groundwatermonitoring well MW-14A. we came to a few concrusions:
1' we could not see a likely source from the Ph.tllipr 99 directly East of the former chevron based on DERRcompliance and past release records for the phillips 66.
2' The DERR records for the former chevron indicate this site is the likely source for the historicalcontamination.
3' Location of additional wells on the Phillips 66 propefi east of the former chevron to help determine a source forthe contamination originating from the Rrrittips_ 6i JJ;if;;;jilr" forr"r chevron would be difficutt considering thebest well locations are those with wells MW-14, MW-14A, ww-"ts, MW-15A, MW-i6 and MW-16A already in place.
iflflfl:?? iifit:il1jfffl'ns a rerease rrom the Phirlips o'o wouro be difficutt d in;;ti with the layoui"itr," existins
4' The wells mentioned in #3 (especially M{-14 and MW-14A) above do not coordinate between the deeper and
;1fl'?:T#;i,T$"Xjll:.and/or Lnafticairesults. p"rriur" ;;;r ror this rras ueen aiscussed between us in the past
5' Groundwater samples from MW-14, MW-14A, MW-15, MW-15A, MW-16 and MW-16A need to be obtained at thesame date on the next sampling event. I realize this is d'ifficult with the weils onen rriving lit6e or no water in themand we should discuss this together further. on the next grounawater sampling event, both John and I want to bethere and have you there too along with the samplers,
"rpl.iiiiv during the sampling of the wells on or associatedwith the Phillips 66 propefi' It would be good to see if tirere is some sort of analysis (pb or additives as some initialsuggestions) to determine potential source-of this off-site contamination. we should probably discuss this further too.
After getting the next sampling event and looking over the results you and/or chevron representatives may want tocome in and discuss further with us any reasons chevron feels the off-site contamination is not from their past fuelingoperations.
This is a rather short summary of my discussion.with John hitting on the highlights as I see them. Feelfree to call meand we can discuss this further before I draft a letter for the ne,,i ,ouno of
-sarn'pling
io u" aonu so I can incorporateyour input into it.
Thanks,
Mike Pecorelli
Project Manager
8or.596.4z9r
file:l/C:\Documents and SettinesWlpecorel\Local Settinss\Temn\Xpornwiqe\{osaFT.nEr.r\^ ^, n, n r^