HomeMy WebLinkAboutDRC-2024-006483
Salt Lake City, UT
-4880
Telephone (801) 536-Fax (801) 536-T.D.D. 711
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah
SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality
Kimberly D. Shelley
Executive Director
DIVISION OF WASTE MANAGEMENT
AND RADIATION CONTROL
Douglas J. Hansen
Director
M E M O R A N D U M
TO: File
THROUGH: Adam Wingate
Uranium Recovery Manager
FROM: Dean Henderson
Hydrogeologist, PG
DATE: July 22, 2024
SUBJECT: Review of the May 15, 2024 1st Quarter, 2024 Chloroform Monitoring Report for the
Chloroform Contamination Investigation (DRC-2024-005689), Energy Fuels Resources
(USA) Inc. (EFRI) White Mesa Uranium Mill (Mill), near Blanding, Utah.
The Utah Division of Waste Management and Radiation Control (Division) has reviewed the May 15,
2024, 1st Quarter, 2024 Chloroform Monitoring Report (Report) for the Chloroform Contamination
Investigation. For the review of this report the following regulatory enforcement documents were used:
EFRI issued Ground Water Quality Discharge Permit No. UGW370004 (Permit). Permit
version that was signed on March 19, 2019.
The EFRI Quality Assurance Plan (QAP) February 15, 2022 (Revision. 7.7)
The EFRI Groundwater Corrective Action Plan (GCAP) September 14, 2015 (Revision 0)
Utah Stipulation and Consent Order Docket Number UGW20-01, September 16, 2015.
REVIEW
GCAP Part III.C requires the 1st Quarter Report to be submitted to the Division on or before June 1, of
each year. The Report was received by the Division on May 21, 2024 (date of Report May 15, 2024)
which meets the GCAP requirement.
Monitor and Pumping Well Sampling
The following 43 monitor wells were sampled as required in the GCAP (see Table 1 below):
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15 pumping wells: MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-21, TW4-22,
TW4-24, TW4-25, TW4-37, TW4-39, TW4-40, and TW4-41.
Current 5 performance monitoring (PM) wells: TW4-7, TW4-10, TW4-16, TW4-26, and TW4-29.
Current 23 compliance monitoring (CM) wells: MW-32, TW4-3, TW4-5, TW4-6, TW4-8, TW4-9,
TW4-12, TW4-13, TW4-14, TW4-18, TW4-23, TW4-27, TW4-28, TW4-30, TW4-31, TW4-32, TW4-
33, TW4-34, TW4-35, TW4-36, TW4-38, TW4-42, and TW4-43.
The water samples for the above wells were analyzed for the following constituents as required in the
QAP:
Chloroform Chloride
Chloromethane Methylene chloride
Carbon tetrachloride Nitrate + Nitrite as Nitrogen.
The analytical methods used are consistent with the requirements of the GCAP. For a summary of the
1st Quarter, 2024 and historic analytical results see Table 1 below.
Groundwater Head Monitoring
Depth to groundwater was measured in the following wells and/or piezometers, as required in Part I.E.3
of the Permit:
-4 and all of the temporary chloroform investigation wells.
-1, P-2, P-3A, P-4 and P-5.
-20 and MW-22.
Investigation.
In addition, weekly and monthly depth to groundwater measurements were taken in pumping wells
MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-21, TW4-22, TW4-24, TW4-25,
TW4-37, TW4-39, TW4-40, TW4-41, TW4-42, and TWN-2.
The monitoring wells were purged using the three approved QAP well purging strategies and meet QAP
requirements for each strategy:
1. Purging two casing volumes with stable field parameters for specific conductivity,
turbidity, pH, redox potential, and water temperature (within 10% RPD):
Wells: MW-32, TW4-5, TW4-8, TW4-9, TW4-16, TW4-18, TW4-23, TW4-32, and TW4-38.
2. Purging a well to dryness and stability of field parameters for pH, specific conductivity, and
water temperature only after recovery:
Wells: TW4-3, TW4-6, TW4-7, TW4-10, TW4-12, TW4-13, TW4-14, TW4-26, TW4-27,
TW4-28, TW4-29, TW4-30, TW4-31, TW4-33, TW4-34, TW4-35, TW4-36, TW4-42, TW4-43.
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3. The pumping wells are continuously pumped on a set schedule and are sufficiently purged to
collect a sample
Pumping Wells: MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19,
TW4-21, TW4-22, TW4-24, TW4-25, TW4-37, TW4-39, TW4-40, and TW4-41.
Holding Times
The water samples for each parameter for samples collected at each monitor well were received and
analyzed within the required holding times stated in the QAP.
Receipt Temperature
Water samples were received within the required QAP temperature limit of 6º C.
Analytical Methods
The analytical methods reported to be used by the laboratory to analyze Chloroform, Chloride,
Chloromethane, Methylene chloride, Carbon tetrachloride, and Nitrate + Nitrite as Nitrogen are
incompliance with analytical methods required in the Chloroform QAP.
Detection Limits
Analyses were measured and reported to the required reporting limits. However, several sets of sample
results had the reporting limit raised for at least one analyte due to matrix interference and/or sample
dilution. In all cases the reported value for the analyte was higher than the increased detection limit.
EFR Duplicate Sample Comparison
Three duplicate samples were collected. Monitor well TW4-28 and its duplicate sample TW4-65, TW4-
16 and its duplicate sample TW4-70, and TW4-7 and its duplicate sample TW4-75. All analytical results
for the three sample/duplicate pairs were within the 20% relative percent difference (RPD) acceptance
limits. (see Table 2 below).
Mass Removed and Plume Residual Mass
Chloroform removal was first estimated from the 1st Quarter, 2007. Since that estimation the mass
removed by each pumping well for each quarter has been calculated. Estimated reported mass removed
during the 1st Quarter 2024 is 5.8 lbs. This estimated mass removed is calculated and verified in Table 3
below. This mass is less than the estimated 10.6 lbs. removed in the 4th Quarter 2023. The decrease in
mass removal is primarily due to a decrease in the concentrations in wells TW4-19, TW4-21 and TW4-
37.
ibed in Appendix A of the GCAP, the
residual mass of chloroform within the plume is estimated as 461 lbs. in the 1st Quarter, 2024. This is
approximately 384 lbs. smaller than the 4th Quarter 2023 estimated mass of 845 lbs. This decrease in
concentration is primarily due to decreases in TW4-19, TW4-21 and TW4-37.
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As per Part III.B.2 of the GCAP, the electronic files were used in 1st Quarter, 2024 to calculate the mass
estimates. The following files were used to calculate the estimated chloroform mass within the
chloroform plume:
Excel spreadsheet that included: well name; well location (easting and northing); Laboratory
reported concentration in µg/l in the 1st Quarter, 2024 and corresponding log equivalent values.
Surfer® griding parameters: kriging parameters: SURFER TM default parameters (point kriging,
linear variogram, slope = 1, no anisotropy [anisotropy = 1], no search constraints; min x, max x
(UTME[m]): 631900, 633043; min y, max y (UTME[m]): 4154240, 4155550.64; grid spacing in
x, y (m): 15.24, 15.24
Surfer chloroform concentration grid file.
Concentration GE 70 Grid file
Intermediate Surfer Grid Files: water level grid; aquifer base grid; saturated thickness grid
Based on the review of these files it appears that the data entered and generated is appropriate to
calculate an estimated chloroform mass within the chloroform plume and EFRI followed Part III.B.2 and
Appendix A of the GCAP.
Reporting
The Report included the following information as required in the QAP:
a) Introduction
b) Sampling and Monitoring Plan
-Description of monitor wells
-Description of sampling methodology, equipment and decontamination procedures
-Identify all quality assurance samples, e.g. trip blanks, equipment blanks,
duplicate samples
c) Data Interpretation
-Interpretation of groundwater levels, gradients, and flow directions.
Interpretations will include a discussion on: 1) A current site groundwater
contour map, 2) hydrographs to show groundwater elevation in each
monitor well over time, 3) depth to groundwater measured and
groundwater elevation from each monitor well summarized in a data table,
that includes historic groundwater level data for each well, and 4) an
evaluation of the effectiveness of hydraulic capture of all contaminants of
concern.
-Interpretation of all analytical results for each well, including a discussion
On: 1) a current chloroform isoconcentration map with one of the
Isoconcentration lines showing the 70 µg/L boundary, 2) graphs showing
Chloroform concentration trends in each well through time and, 3)
Analytical results for each well summarized in a data table that includes
Historic analytical results for each well.
-Calculate chloroform mass removed by pumping wells. Calculations
would include: 1) total historic chloroform mass removed, 2) total historic
chloroform mass removed for each pumping well, 3) total chloroform
mass removed for the quarter and, 4) total chloroform mass removed from
each pumping well for the quarter, 5) estimated residual mass of chloroform within the
plume.
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d) Conclusions and Recommendations
e) Electronic copy of all laboratory results for Chloroform Investigation monitoring conducted
during the quarter.
f) Copies of DUSA field records, laboratory reports and chain of custody forms.
Evaluation of the Chloroform Contaminate Plume and Its Associated Contaminants.
Bounding Chloroform Plume
Groundwater monitoring data up to the 1st Quarter, 2024 monitoring event appeared to show that the
chloroform contaminate plume (Plume) and associated contaminants (carbon tetrachloride,
chloromethane, and methylene chloride) is bound by up gradient, cross gradient, and down gradient
compliance monitoring wells that have a chloroform concentration of <70 µg/L (GWQS = 70 µg/L).
Performance Monitor Wells (PM) [Wells Exceeding Chloroform Concentrations GWQS of 70µg/L]
Five (5) PM wells still exceed 70 µg/L: TW4-7, TW4-10, TW4-16, TW4-26, and TW4-29.
Compliance Monitor Wells (CM) [Wells with Chloroform Concentrations between 1 and 70µg/L]
Ten (10) CM wells range with detectable chloroform concentration but still below 70µg/L: TW4-5,
TW4-6, TW4-8, TW4-9, TW4-18, TW4-27, TW4-30, TW4-33, TW4-34 and TW4-35.
CM Wells Below the Laboratory Chloroform Detection Limit (<1.0 µg/L)
Fourteen (13) CM wells were below the laboratory detection limit for chloroform (<1.0 µg/L): MW-32,
TW4-3, TW4-12, TW4-13, TW4-14, TW4-23, TW4-28, TW4-31, TW4-32, TW4-36, TW4-38, TW4-
42, and TW4-43.
Pumping Wells
There are 14 pumping wells as a part of the chloroform pumping system in full operation in the 1st
Quarter, 2024. Wells MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-21 TW4-22,
TW4-24, TW4-37, TW4-39, TW4-40, and TW4-41 exceed chloroform concentrations of 70 µg/L. At
this time the chloroform pumping system appears to be capturing most if not all the chloroform plume.
Concentrations.
Pumping wells TW4-22 (53.9 mg/L), TW4-24 (40.6 mg/L) and TW4-37 (33.9 mg/L) exceed the nitrate
GWQS of 10 mg/L. These nitrate exceedances appear to be a result of the nitrate contaminant plume
up-gradient of the chloroform contaminant plume. This nitrate contaminant plume is being addressed
under the Nitrate Corrective Action Plan, approved on December 12, 2012.
Well TW4-26 (10.2 mg/l) continues to exceed the nitrate GWQS of 10 mg/l. The source of nitrate may
be from the chloroform plume. Pumping well TW4-40 is located approximately 200 feet down gradient
of TW4-26 and the nitrate concentrations in the 1st quarter 2024 were below the nitrate GWQS of 2.02
mg/L. Therefore, at this time no action is recommended. However, should future nitrate concentrations
in down gradient pumping well increases to above 10 mg/L or shows an increasing trend an additional
investigation may be recommended
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Well, TW4-27 (15.1 mg/L) continues to exceed the nitrate GWQS of 10 mg/l. The source of nitrate may
be from the chloroform source plume. Wells TW4-29, TW4-30, and TW4-31 located approximately
200 feet down and/or cross gradient of TW4-27 have nitrate concentrations in the 1st quarter 2024
below the nitrate GWQS at 2.80 mg/L, 3.21 mg/L, and 0.500 mg/L respectively and appears to bound
the nitrate in this vicinity. Therefore, at this time no action is recommended. However, should future
nitrate concentrations in these three down and/or cross gradient wells increase to above 10 mg/L or show
an increasing trend an additional investigation may be recommended.
Well TW4-28 (11.8 mg/l) continues to exceed the nitrate GWQS of 10 mg/l. The source of nitrate may
be from the chloroform plume. Well TW4-32 is located approximately 200 feet down gradient of TW4-
28 and the nitrate concentrations in the 1st quarter 2024 were below the nitrate GWQS at 1.83 mg/L.
Therefore, at this time no action is recommended. However, should future nitrate concentrations in
down gradient pumping well increases to above 10 mg/L or shows an increasing trend an additional
investigation may be recommended
Conclusions on Compliance with the Permit and QAP
After review, it appears that the Report complies with Permit, QAP, and GCAP. Therefore, a letter will
be drafted notifying EFRI of the review and closing out of for the May 15, 2024, 1st Quarter, 2024
Chloroform Monitoring Report for the chloroform contamination investigation.
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References
-20-01 White
Mesa Mill
Attachment 1 to the SCO, January 10, 2018.
EFRI issued Ground Water Quality Discharge Permit No. UGW370004. Permit version that was
signed on March 19, 2019.
EFRI, White Mesa Uranium Mill Chloroform Monitoring Report 4th (October through
December) 2023. (DRC-2024-004574)
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Tables 1 through 3