DERR-2025-000077

Leigh Anderson <[e-mail]>
GE N. Salt Lake, Proposed Modification to Offsite GW Sampling
1 message
Glisson, Bradley <[e-mail]>Mon, Aug 26, 2024 at 3:30 PM
To: Leigh Anderson <[e-mail]>
Cc: "Mathews, Sara" <[e-mail]>, Scott Everett <[e-mail]>, Bill Rees <[e-mail]>, "Foti,
Damian D (GE Vernova)" <[e-mail]>
Hello Leigh,

As discussed during our call with your team on Thursday (8/22), we propose the following modifications to the offsite
groundwater sampling, which will take effect during the September sampling event:

Regarding 1,4-dioxane analysis:
The results from April 2024 indicated detecons for 1,4-dioxane in 1 of the 12 offsite wells, which was A-2 at 3.35 µg/L (EPA
RSL is 0.46 µg /L)
Results from April 2024 indicate no detecons in eleven (11) of the 12 offsite wells at the MDL of 0.597 µg /L.
Based on the non-detect data in 11 of 12 off site wells, WSP’s Plume Analycs Services from April 2024 provides an
interpretaon of the leading edge of the plume to include A-1 and A-2 and stop short of any addional wells. (see aached
screenshot)
With groundwater flow to the west/northwest, the following wells can be considered downgradient of the plume: A-3, A-5,
and A-10
Therefore, WSP proposes sampling and analysis (8260 SIM low level) of A-1, A-2, A-3, A-5, and A-10 to monitor for 1,4-
dioxane during the September sampling event. And, only gauging will be completed for A-4, A-6, A-7, A-8, A-9, A-11, and A-
12.

Regarding VOC analysis:
Results from groundwater analysis by Method 8260 in April 2024 indicated only trichloroethene above the EPA RSL in A-1 and
A-2
TCE detecons below the EPA RSL were also reported in A-3, A-4, A-5, A-6, A-7, and A-8 (Note: Results of compound specific
isotope analysis (CSIA) in July 2023 indicated TCE in samples from the GE site and offsite are from different sources)
1,1,1-Trichloroethane was detected in April 2024 in well A-10 at 1.7 µg /L (EPA RSL is 200 µg/L) – 1,1,1-TCA has not been
detected in groundwater wells at the GE site since sampling began in 2018. Since 1,4-dioxane was used as a stabilizer for
1,1,1-TCA, this detecon could be interpreted as an offsite source of 1,4-dioxane.
Therefore, WSP proposes sampling and analysis of A-1, A-2, and A-10 for VOCs by 8260D.

We request your reply to this email by the end of the day tomorrow (Tuesday, August 27th) in order for us to make
appropriate arrangements.

Best,

1/5/25, 9:50 AM State of Utah Mail - GE N. Salt Lake, Proposed Modification to Offsite GW Sampling
https://mail.google.com/mail/u/0/?ik=5be3741f93&view=pt&search=all&permthid=thread-f:1808487272498483374&simpl=msg-f:1808487272498483374 1/2
Brad Glisson, CHMM
Assistant Vice President, Environmental Scientist

T+ 1 615-333-0630
M+ 1 615-479-0941

WSP USA
216 Centerview Drive, Suite 300
Brentwood, TN 37027

wsp.com

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GE North Salt Lake, Plume Analytics Services April 2024 (1,4-dioxane).jpg
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1/5/25, 9:50 AM State of Utah Mail - GE N. Salt Lake, Proposed Modification to Offsite GW Sampling
https://mail.google.com/mail/u/0/?ik=5be3741f93&view=pt&search=all&permthid=thread-f:1808487272498483374&simpl=msg-f:1808487272498483374 2/2