WQ0023896_Explanation for GW59 Exceedances_20240418

Baker, Caroline D
From: Daw, Larry <[e-mail]>
Sent: Thursday, April 18, 2024 2:36 PM
To: Hall, Michael
Cc: Manuel, Vanessa; Clark, Timothy W; Postyn, Adam
Subject: [External] UNC Bingham Facility - Ground water constituents exceeding standards
March 2024
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Mike,
We completed permit required quarterly groundwater sampling at the UNC Bingham Facility on March 7, 2024, and the following
constituents exceeded standards:
3-7-2024 MW-3 pH 6.1 SU
3-7-2024 MW-3 Fecal Coliform 9 colonies/100 ml
3-7-2024 MW-4 pH 5.7 SU
As is usual, we continue to measure pH values in groundwater at the facility below 6.5 SU.
For the December 2023 sampling event MW-3 and MW-4 were purged and sampled using a peristaltic pump with new tubing. A
peristaltic pump with new tubing was also used on MW-3 and MW-4 for this March 2024 sampling event.
Historically, we have used bailers to purge and sample wells at Bingham. As you are aware, we switched to using a peristaltic pump
in an attempt to see if the presence of fecal could have been an artifact of the sampling procedures used. Given the continued
detection of fecal in these two wells during the two previous quarterly sampling events, we plan to return to using bailers during
future sampling events.
Please let me know if you have any questions. Thank you.
Larry Daw, L.G.
Environmental Compliance Officer lGeophysicist I Licensed Geologist
INSTITUTIONAL INTEGRITY AND RISKMANAGEMENT
,C1UNCJ Environment, Health and Safety
THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL
ENVIRONMENT, HEALTH & SAFETY
1120 Estes Drive I Campus Box 1650 1 Chapel Hill, NC 27599-16501 www.ehs.unc.edu
Office: 919.962.6666 1 Mobile:[phone] JEmail: [e-mail]
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UNC Environment, Health and Safety