DRC-2023-071346 - 0901a06881267ce0

Department of Environmental Quality
Kimberly D. Shelley Executive Director SPENCER J. COX Governor DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL
DEIDRE HENDERSON lieutenant Governor Douglas J. Hansen Director MEMORANDUM
TO: PhilGoble ,/?£.6 �fFROM: Dean Henderson /},!JI 6 -JJf3� Z, '5
DATE: August 28, 2023
SUBJECT: Review of the May 18, 2023 1st Quarter, 2023 Chloroform Monitoring Report for the Chloroform Contamination Investigation, Energy Fuels Resources (USA) Inc. ("EFRl") White Mesa Uranium Mill ("Mill"), near Blanding, Utah.
The Utah Division of Waste Management and Radiation Control ("Division") has reviewed the May 18, 2023, 1st Quarter, 2023 Chloroform Monitoring Report ("Report") for the Chloroform Contamination Investigation. For the review of this report the following regulatory enforcement documents were used:
•EFRl issued Ground Water Quality Discharge Permit No. UGW370004 ("Permit"). Permitversion that was signed on March 19, 2019.•The EFRI Quality Assurance Plan ("QAP") September 10, 2019 (Revision. 7.6)•The EFRl Groundwater Corrective Action Plan ("GCAP") September 14, 2015 (Revision 0)•Utah Stipulation and Consent Order Docket Number UGW20-0l, 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 24, 2023 (date of Report May 18, 2023) 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):
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.
DRC-20 195 North 1950 West • Salt Lake City, UT Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880 Telephone [phone] • Fax [phone] • T.D.D. [phone] www.deq.utah.gov Printed on 100% recycled paper
DRC-2023-071346
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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 Chloromethane Carbon tetrachloride
Chloride Methylene chloride Nitrate + Nitrite as Nitrogen.
The analytical methods used is consistent with the requirements of the GCAP. For a summary of the 1st Quarter, 2023 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:
•The quarterly groundwater compliance monitoring wells.•Existing monitoring well MW-4 and all of the temporary chloroform investigation wells.•Piezometers P-1, P-2, P-3A, P-4 and P-5.•MW-20 and MW-22.•Nitrate monitoring wells.
•The DR piezometers which were installed during the Southwest Hydrologic Investigation.
In addition, weekly and monthly depth to groundwater measurements were taken in pumping wells MW-4, MW-26, TW4-l, 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, andwater 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.
3.The pumping wells are continuously pumped on a set schedule and are sufficiently purged tocollect a sample
Pumping Wells: MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19,
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TW4-21, TW4-22, TW4-24, TW4-25, TW4-37, TW4-39, TW4-40, and TW4-41.
Holding Times
The water samples method holding times 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 6° C.
Analytical Methods
The analytical methods reported to be use 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, and TW4-9 and its duplicate sample TW4-70; and TW4-16 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.
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 2023 is 5.9 lbs. (see Table 3 below) which is lesser than the estimated 15 lbs. removed in the 4th Quarter 2022. The lower mass removal is primarily due to. a decrease in the concentrations in TW 4-19.
Using the "Chloroform Plume Mass Calculation Method" as described in Appendix A of the GCAP the residual mass of chloroform within the plume is estimated as 444 lbs. in the 1st Quarter, 2023. This is approximately 449 lbs. smaller than the 4th Quarter 2022 estimated mass of 893 lbs.
As per Part III.B.2 of the GCAP, the electronic files were used in 1st Quarter, 2023 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); Laboratoryreported concentration in µg/1 in the 1st Quarter, 2023 and corresponding log equivalent values.
Page 4 •Surfer® griding parameters: kriging parameters: SURFER™ 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 inX, 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 gridBased on the review of these files it appears that the date 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)Introductionb)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 samplesc)Data Interpretation-Interpretation of groundwater levels, gradients, and flow directions.Interpretations will include a discussion on: 1) A current site groundwatercontour map, 2) hydrographs to show groundwater elevation in eachmonitor well over time, 3) depth to groundwater measured andgroundwater elevation from each monitor well summarized in a data table,that includes historic groundwater level data for each well, and 4) anevaluation of the effectiveness of hydraulic capture of all contaminants ofconcern.-Interpretation of all analytical results for each well, including a discussionOn: 1) a current chloroform isoconcentration map with one of theIsoconcentration lines showing the 70 µg/L boundary, 2) graphs showingChloroform concentration trends in each well through time and, 3)Analytical results for each well summarized in a data table that includesHistoric analytical results for each well.-Calculate chloroform mass removed by pumping wells. Calculationswould include: 1) total historic chloroform mass removed, 2) total historicchloroform mass removed for each pumping well, 3) total chloroformmass removed for the quarter and, 4) total chloroform mass removed fromeach pumping well for the quarter, 5) estimated residual mass of chloroform within theplume.d)Conclusions and Recommendationse)Electronic copy of all laboratory results for Chloroform Investigation monitoring conductedduring the quarter.
Page 5 t)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, 2023 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] Nine (9) 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. CM Wells Below the Laboratory Chloroform Detection Limit (<1.0 µg/L) Fourteen (14) 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, TW4-35, TW4-36, TW4-38, TW4-42, and TW4-43. Pumping Wells There are 15 pumping wells in full operation in the 1st Quarter, 2023, 14 pumping wells MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-ll, TW4-19, TW4-21 TW4-22, TW4-24, TW4-37, TW4-39, TW4-40, and TW 4-41 exceed chloroform concentrations of 70 µg/L. Pumping well TW 4-25 had a non­detectable (<1.0 µg/L) chloroform concentration (see table 1 below). Nitrate, Nitrate + Nitrite ("nitrate") Concentrations Pumping wells TW4-21 (10.9), TW4-22 (49.1 mg/L), TW4-24 (36.2 mg/L) and TW4-26 (10.5 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 TW4-27 (20.9 mg/L) continue to exceed the nitrate GWQS of 10 mg/I. 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 ofTW4-27 have nitrate concentrations in the 1st quarter 2023 below the nitrate GWQS of 2.74 mg/L, 2.84 mg/L, and 0.391 mg/L respectively. Therefore, at this time no action is recommended. However, should future nitrate concentrations in these three down and/or cross gradient wells increases to above 10 mg/L or shows an increasing trend an additional investigation may be recommended. Well TW4-28 (11.9 mg/L) exceed the nitrate GWQS of 10 mg/I. The source of nitrate may be from the chloroform source plume. Well, TW4-32 located approximately 200 feet down gradient ofTW4-28 has a nitrate concentration in the 1st quarter 2023 below the nitrate GWQS of 1.59 mg/L. Therefore, at this time no action is recommended. However, should future nitrate concentrations in down gradient well
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Ta bles 1 through 3
TABLE 1 (1 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
MW-4 (chloroform pumpl"lil well
atartedpumpingl/4/03) Sampling Event
1st OIi 3/16/2005 2nd Qtr 5/25/2005 3rd OIi 8/31/2005 4th QtI 12/7/2005 1stQtr 3/9/2006 2nd Otr 6/14/2006 3rd Qtr 7/20/2006 4th OIi 11/8/2006 1stQtr 2128/2007 2nd Otr 6/27/2007 3rd Qtr 8/15/2007 4thOtr 10/10/2007 1stQtr 3/28/2008
EQtr 6/25/2008 Qtr 9/10/2008 Otr 10/15/2008 1s1Qtr 3/4/2009 2nd Qtr 6/23/2009 3rd Otr 9/14/2009 4th Qtr 12114/2009 1stOtr 2117/2010 2nd Qtr 6/14/2010 3rd Qtr 8/6/2010 Qtr 10/15/2010 Qtr 2123/2011 jQt, 6/1/2011 Qtr 8/17/2011 "" 11/16/2011 ,,.r(1) 1/23/2012 !2nd Qtr ---6/6/2012 13rd Otr 9/4/2012 14th Qtr 10/4/2012 1stOtr 2111/2013 12nd Qtr 6/5/2013 13rd Otr 9/3/2013 Qtr 10/29/2013 Qtr 1/27/2-014 dQlr 5/19/2014 Qtr 8/11/2014 Qtr 10/21/2014 Qtr(2) --3/9/2015 2nd Qtr 6/8/2015 3rd Qtr 8/31/2015 4thQtr 10/19/2015 1stQtr 3/9/2016 2nd Otr 5/23/2016 3rd Qtr 7/25/2016 4th Otr 10/1212016 1st Qtr 3/8/2017 2nd Qtr 6/13/2017 3rd Otr 7/26/2017 4th Qtr 10/11/2017
OWMRC solit samcle 1st Otr 3/12/2018 2nd Qtr 6/8/2018 3rd Otr 8/2212018 4th Qtr 11/28/2018 fsi"citr 3/8/2019 2nd atr 6/5/2019 3rd Qtr 9/4/2019 4th Qtr 12110/2019 ist Otr 2Tfai2020 2nd Qtr 5/27/2020 3rd Qtr 9/4/2020 4th Qtr 10/18/2020 1stOtr 2/23/2021 2nd Otr 6/9/2021 3rd Qtr 8/24/2021 4th Qtr 1211/2021 1stQtr 3/9/2022 2nd Otr 6/8/2022 3rd Qtr 8/30/2022 4th Otr 11/30/2022 1stOtr 3m2023 MW-4A I w4-Al 1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4thOtr 12/7/2005 1stOtr 3/9/2006 2nd Otr 6/14/2006 3rdQtr 7/20/2006 4thQtr 11/8/2006 1st Qtr 2128/2007
Carbon Tetrachloride Chloroform 15 ug/L) 170 ua/L) NA 2,900 NA 3,170 <10 3,500 <50 3,000 <50 3,100 <50 3,000 <50 2,820 2.1 2,830 1.6 2,300 1.8 2,000 1,9 2.600 1.7 2,300 1.7 2.400 1.8 2,500 1,8 1,800 1.7 2,100 1,5 2,200 ,,. 1.3 1,800 1.4 2.000 1.6 1,800 1.2 1,600 1,2 2,100 1.5 1,900 1.4 1,500 1.5 1,700 1,4 1.700 1.1 1.700 1.3 1,600 1 1,506" 1.2 ---"'iAoiJ1.5 1,500 1 1,300 1.48 1,670 1.31 1.490 1.13 1,520 5.58 1,410 4.15 1,390 5.21 1,390 7.6 1,490 <1.0 1,440 1.26 ---"'iAoiJ <1.0 1,300 <1.0 1,200 <1.0 1,200 <1.0 1,240 1.44 1,580 <1.0 1,430 1.24 1.470 1.22 1.450 1.15 1.430 1.15 1,400 <1.0 1,320 <19 1.400 1.07 1,320 <1.0 1,240 <1.0 1,300 <1.0 1,330
<1.0 u!io <1.0 1,300 <1.0 1,180 <1.0 1,370 <1.0 1,230 <1.0 1,250 <1.0 1,240 <1.0 1,050 <1.0 1,150
<1.0 1,320
<1.0 1,140 <1.0 1,100 <1.0 1,040 <1.0 1,010 <1.0 1,200 <1.0 1,170 <1.0 1 010
NA 3,700 NA 3,740 <10 3,800 <50 3,000 <50 3,700
<50 3,300 <50 3,190 2.4 3,370 1.9 2,500
(1) As of Match 2012 both north and south wild llfe ponds no longer receMng water (2) chloroform pumping wells TW4-1, TW4-2, and TW4-11 started lfl 1114/15 __ _ NA = not analyzed Shaded indicates concentrations exceeding GWQS.
Bold and italics indicates the MDL exceeded the GWQS.
J :a: Approximated value
DUSA White Mesa Mill
Parameter IGWQSl Chloromethane Methylene Chloride (30 ua/Ll (5 ug/Ll NA NA NA NA <10 <10 <50 <50 <50 <50 <50 <50 <50 <50 1.4 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T_o------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T_o------<1.0 1.42 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <30 <1.0 <1.0 <1.0 <1.0 <1,0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
NA NA <10 <50 <50 <50 <50 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 -------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 .<"f.o <1.0 <1.0 <1.0 <1_0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 70 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
NA NA <10 <50 <50 <50 <50
<1.0 <1.0 Well abandonded
Chloride No GWQS (ma/Ll NA NA NA 53 49 49 48 50 47 45 47 45 42 42 35 45 37 34 43 44 45 41 38 41 40 35 41 40 --------41.0 39.0 41.0 41.0 37.8 44.0 41.4 40.1 38.5 39.9 41.0 --------41,5 40.7 43.1 44.3 40.8 42.2 43.7 42.5 44.8 43.3 44.0 43.8 43.8 43.0 46.2 43.5 48.5 43,1 41.5 40.6 41.9 45.5 48.1 40.7 43,8 41.4 46.5 34.8 43.2 47.6 40.9 43,7 44.7 35.9 29.4
NA NA NA 55 53 54 54 54 60
Nitrate, Nitrate + Nitrite (10 mg/LI 6.3 7.1 7.0 7.0 6.0 6.0 1.2 6.4 6.3 7.0 6.2 6.2 5.8 6.1 6.4 5.9 5.7 5.2 5.3 5.8 4.0 5.1 4.8 4.9 4.6 4.9 4.9 5.1 ___________ !-� 4.9 5.0 4.8 4.78 4.22 4.89 5.25 4,7 4.08 3.7 ----------5jl� 5.75 2.53 4.79 4.43 5.15 4.54 4.95 4.88 4.99 4.88 4.59 5.25 5.1 4.47 4.64 4.55 4.44 5.05 5.16 4.69 4.34 6.22 5.04 4.93 4.62 4.61 6.48 3.83 4.90 4.80 3.90 4.20 4.05 4.44
7.1 7,8 6.9 6.7 5.8 7,3 1.2 7.1 7.1
TABLE 1 (2 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
MW-26 {10fmlll' lW4-15) ChiofofOfm pumping well lllll1ed 8/IIOJ Parameter
Sampling Event IGWQS) Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride
/5ua/Ll (70 ua/LI 130 ua/LI (5 µg/LI 3rd Qtr 9/2/2002 NA 2.6 NA NA
4th Qtr 11/2/2002 NA <1.0 NA NA tstQtr 3/3/2003 NA <1.0 NA NA 2nd Qtr 6/2312003 NA 7800 NA NA 3rd Qtr 9/1212003 NA 2500 NA NA
4th Qtr 1.l/§.@03 NA 3000 NA NA
1st Qtr 3116/2005 NA 310 NA NA 2nd Qtr 5/25/2005 NA 442 NA NA 3rd Qtr 8131/2005 <5.0 960 5.4 <5.0
4thOtr 1217/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd Otr 7/20/2006
4thOtr 11/8/2006 1stQtr 2128/2007 2nd Qtr 6/27/2007 3rd Otr 8/15/2007 4thQtr 10/10/2007 1stQtr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008
4th Qtr 10/15/2008 11/18/2008 tstQtr • 3/4i2009
2nd Qtr 6123/2009 3rd Qtr 9/14/2009
4th Otr 12114/2009 1stQtr 2117/2010 2nd Qtr 6/14/2010 3rd Qtr 8/16/2010
4thQtr 10/15/2010 1stOtr 2/23/2011 2nd atr 5131/2011 3rd Qtr 8/17/2011
4thOtr 11/16/2011
/1\ 1215/2011 11StQ1r{2L __ 212712012 2nd atr 6/6/2012
<50 1.000 <50 <50 1.100 <50
<50 830 <50 <50 2.170 <50 <1.0 282 <1.0 <1.0 570 <1.0 <1.0 300 <1.0 <1.0 1.400 <1.0 <1.0 2.000 <1.0 <1.0 930 <1.0 <1.0 1.300 <1.0 <1.0 630 <1.0 NA NA NA <2.0 1.700 <2.0 <1.0 950 <1.0 <1.0 410 <1.0 <1.0 850 <1.0 <1.0 1.100 <1.0 <1.0 730 <io1.2 1.600 <1.0 <1.0 2.200 <1.0 <1.0 970 <1.0 <1.0 450 <1.0 <1.0 1.800 <1.0 <1.0 720 <1.0 NA NA NA <1.0 1.800 <1.0 <1.0 2.400 <1.0 --------------1:000 <T.O ______ <1.0 3rdQtr 914/2012 <1 3.100 <1
4thOtr 10/4/2012 <1 1.200 <1 tstOtr 2111/2013 <1 2.120 <1 2nd Qtr 6/512013 3rd Otr 9/3/2013
4thOtr 10/29/2013 1st Qtr ··,,21,2014 2nd atr 5/19/2014 3rd Qtr 8/11/2014
4th Qtr 10/21/2014 1stQtr 3/9/2015 2nd Qtr (3) 6/8/2015 3rd Qtr 8131/2015
4thOtr 10/1912015 1stOtr 3/9/2016 2ndQtr 5/23/2016 3rdQtr 7/25/2016 4th Qtr (4) 10/1212016 1st Qtr -318/2017 2nd Qtr 6/13/2017 3rd Qtr 7/26/2017
4thQtr 10/11/2017 1st Otr 3/1212018 2nd Qtr 6/8/2018 3rd Qtr 8/2212018 4th Qtr 11/28/2018 1st Qtr .... 3/8/2019 2nd atr 61512019 3rd Qtr 9/412019
4th Qtr 12110/2019 1st Qtr 2119/2020 2nd Qtr 6/1212020 3rd Qtr 9/4/2020 4th Qtr 10/28/2020 1st Qtr 2/23/2021
2nd Qtr 6/6/2021 3rd Qtr 8/2412021 4th Qtr 1211/2021 1stQtr 3/9/2022
2nd atr 6/8/2022 3rd Qtr 8/30/2022 4th Qtr 11/30/2022 1stQtr 3/9/2023
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ---------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
4.030 2.940 1.410 1.400 1.960
2.120 2.090 1.980 1,980 ---2]502.680 -···-2.650 2.220 3.190 2,510 ---·uoo 2.450 1.230 2.570 1.210 1.870 1.680 1.480 1.110 1.280 1.680 1.390 1.100 1.140 1.130 866 3.060 998 1.580 826 1.030 611 612 1.040 571 (1) VOCs were resampled because laboratory missed holding time. (2) As of March 2012 both north and south wild !1fe ponds no loni!r receMfl...,i water (� ch!oroTorm .,eume!."i. weli'1w4•3" started 1n 6'i9/15 __________ • j4) chloroform.,eume.:.n.a_we!ls TW4-1, TW4·2. and TW4-11 started In 1/14/15 -· NA = not analyzed Shaded indicates concentrations exceedin!l GWQS. Bold and italics indicates the MDL exceeded the GWQS.
<1.0 <1.0 <1 :t1.o <1.0 8.7 <1.0 <1.0 <1.0 ------4.05 1.32 <1.0 <1.0 <1.0 <1.0 <T.O ______ <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ·<·n,<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 5.9 <1.0 <1.0 <1.0 <1.0 <1.0
<50 <50 <50 <50 2.6 5.5 13 36 14 40 53
24 NA 100 51 12 30 40 ··-·-···-·· 19 <1.0 21 6.5 3.6 1.3 7.2 NA 2.9 16 ----------21 31 4 9.34 52.4 33.2 4.03. 13.8 15.4 26
23.2 27.4
--------11.2 11.6 ·························8.28
4.66 4.57 7.81
4.31 7.65 7.59 5.26 7.83 2.14 9.19 <1.0 <1.0
2.2 1.19 1.93 1.78. <1.0 <1.0 2.57 <1.0 3.46 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS Ima/LI NA NA NA NA NA NA
NA NA NA 55 52 52 65 54 56 49 57 57 49 57 44 64 --···-..... , .... _ .NA 49 48
46 60 57 40
49 65 57 88 58 69 NA
---------98 73 73 68 81.9 77.9 60.5 72.3 59:4 53.4 59 60.1 56.5
---------62 69.6 62.6 68.3 66.2 66.4 66.2 58.4 64.3 61.4 62.2 60.3 58.7 91.4 85.5 69.9 80.7 76.2 83.2 88.9 35.1 70 37.4 59.5
48.6
46.6 84.7 50.2 63.4 57.0 52.1 61
Nitrate, Nitrate + Nitrite (10mg/L) NA NA NA NA NA NA
0.3 0.2 0.2 0.3 0.2 0.2 1.4 0.3 0.6 0.4 1 0.6 0.1 0.6 0.2 0.1 NA 0.4 0.2 0.1
2.3 0.2 6.8 0.6 0.7 0.5 0.4 0.9 2.0 NA ----------· !·I 2.5
2.6 1.8 2.27
2.11 1.18 1.38 0.55 0.93 0.7 0.93 0.73 ----------0�42 0.68 0.991 ··-··------------· 1.45 1.12 1.57 1.18 ----------0.768 0.922 1.56 1.18 1.57 0.901 2.80 1.96 1.85 2.83 3.08 0.977 1.17
2.93 0.42 3.62 0.349 0.81 0.671 0.52 0.3 0.22 0.662 0.337 0.694
TABLE 1 (3 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
MW-32 (lonne, TW4•17) Sampling Event
1statr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4th Qtr 12/7/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd Qtr 7/20/2006 4th Qtr 11/8/2006 'fSTatr 2128/2007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1stOtr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 1stOtr 3/4/2009 2nd Qtr 6/23/2009 3rd Qtr 9/14/2009 4th Qtr 12116/2009 1st Qtr 2117/2010 2nd Qtr 6/14/2010 3rd Qtr 8/16/2010 4thOtr 10/15/2010 1st Ctr 2/23/2011 2nd Qtr 5/25/2011 3rd Qtr 8/18/2011 4th Qtr 11/16/2011 (1) 12/7/2011 istc,tr{,� __ 1/18/2012 2nd Qtr 6/2212012 3rd atr 9/5/2012 4th Qtr 10/10/2012 1stOtr 2/11/2013 2nd Qtr 6/18/2013 3rd Qtr 9/3/2013 4th Qtr 10/29/2013 1st Ctr 1/29/2014 2nd Qtr 5/23/2014 3rd Otr 8/26/2014 4th Qtr 10/29/2014 'isiotr 3/17/2015 2nd Qtr 6/11/2015 3rd Qtr 9/9/2015 4th Qtr 10/28/2015 1st Ctr 3/2212016 Duplicate TW4-70 2nd Qtr 6/8/2016 Duplicate TW4-70 3rd Qtr 8/19/2016 4th Qtr 10/31/2016 1stQtr 3/21/2017 2nd Qtr 6/21/2017 3rd Qtr 8/8/2017 4th Qtr 10/1212017 1st Ctr 3/15/2018 Duplicate TW4-70
i�cd Qtr 6/14/2018 dQtr 9/2212018 4thQtr 10/29/2018 1stQtr 3/19/2019 2nd Qtr 6/18/2019 3rd Qtr 9/11/2019 "" ,..,., 12118/2019 1statr 3/18/2020 Dupl1eate TW4-75 2nd Qtr 6/1212020 13rd Qtr 9/18/2020 14th Qtr 11/4/2020 lnunlir.:i.t"'TW4-65 1statr 3/18/2021 !Duplicate TW4-75 12nd Qtr 6/17/2021 !Duplicate TW4-75 13rd Q1r 9/23/2021 !Duplicate TW4-75 14th Q1r 1219/2021 1stQtr 3/2212022 12nd Q1r 6/16/2022 3rd Qtr 9/15/2022 41h Qtr 1218/2022 1s1Qtr 3i30i2023
Carbon Tetrachloride Chloroform 15 ua/Ll 170 ug/L) NA <1.0 NA <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1 .. 0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA NA <1.0 <1.0 <1.0 ---------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1."o <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 (1) VOCs were resampled because laboratory missed holding bme. (2) As of March 2012 both north and south WIid life ponds no longer receN10g water NA = not analyzed Shaded indicates concentrations exceeding GWQS.
OUSA White Mesa Mill
Parameter lGWQSI Chloromethane Methylene Chloride Chloride Nitrate, Nitrate+ Nitrite 130 ug/L) 15 ua/Ll No GWQS Ima/LI •10mg/Ll NA NA NA <0.1 NA NA NA <0.1 3.2 <1.0 NA <0.1 <1.0 <1.0 33 <0.1 <1.0 <1.0 32 <0.1 3.5 <1.0 30 <0.1 1.8 <1.0 32 <1.0 1.5 <1.0 31 <.1 <1.0 <1.0 32 <1.0 <1.0 <1.0 32 <1.0 <1.0 <1.0 31 <1.0 <1.0 <1.0 32 <1.0 <1.0 <1.0 31 <.1 <1.0 <1.0 29 <1.0 <1.0 <1.0 30 <1.0 <1.0 <1.0 26 <0.05 <1.0 <1.0 30 <.1 <1.0 <1.0 31 <0.1 <1.0 <1.0 33 <0.1 <1.0 <1.0 35 <0.1 <1�0 <1.0 38 <0.1 <1.0 <1.0 32 <0.1 <1.0 <1.0 28 <0.1 <1.0 <1.0 24 <0.1 <1.0 <1.0 40 <0.1 <1.0 <1.0 31 <0.1 <1.0 <1.0 33 <0.1 NA NA 32 <0.1 <1.0 <1.0 NA NA <1.0 <1.0 21 <0.1 --------<1.0 ---------------32 ------------<1.0 <0.1 <1.0 <1.0 33 <0.1 <1.0 <1.0 35 <0.1 <1.0 <1.0 34.3 <0.1 <1.0 <1.0 34.9 <0.1 <1.0 <1.0 33 <0.1 <1.0 <1.0 35.7 <0.1 <1.0 <1.0 34 <0.1 <1.0 <1.0 39.7 <0.1 <1.0 <1.0 34 <0.1 <1.0 <1.0 34.9 <0.1 <·ro <1.0 36.3 <0.1 <1.0 <1.0 35.8 <0.1 <1.0 <1.0 37.7 <0.1 <1.0 <1.0 34.7 <0.1 <1.0 <1.0 36.7 <0.1 <1.0 <1.0 37.7 0.119 <1.0 <1.0 36.4 <0.1 <1.0 <1.0 37.7 <0.1 <1.0 <1.0 35.7 <0.1 <1.0 <1.0 36.9 <0.1 <1.0 <1.0 33.7 <0.1 <1.0 <1.0 37.2 <0.1 <1.0 <1.0 38.1 <0.1 <1.0 <1.0 32.6 <0.1 <1.0 <·1.o 39.4 <0.1 <1.0 <1.0 39.3 <0.1 <1.0 <1.0 34.4 <0.1 <1.0 <1.0 41.2 <0.1 <1.0 <1.0 32.9 <0.1 <1.0 <1.0 35.3 <0.1 <1.0 <1.0 36.5 <0.1 <1.0 <1.0 41.2 <0.1 <1.0 <1.0 36.3 <0.1 <1.0 <1.0 36 <0.1 <1.0 <1.0 34.8 <0.1 <1.0 <1.0 35.6 <0.1 <1.0 <1.0 34.7 <0.1 <1.0 <1.0 31.3 <0.1 <1.0 <1.0 35.9 <0.1 <1.0 <1.0 36.8 <0.1 <1.0 <1.0 37.4 <0.1 <1.0 <1.0 35.8 <0.1 <1.0 <1.0 34.3 <0.1 <1.0 <1.0 35.3 <0.1 <1.0 <1.0 35.5 <0.1 <1.0 <1.0 35.8 <0.1 <1.0 <1.0 28.6 <0.1 <1.0 <1.0 26.9 <0.1 <1.0 <1.0 37.2 <0.1 <1.0 <1.0 35.1 <0.1 :::1.·o <1.0 36.8 "<"0.1
TABLE 1 (4 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-1 (chloroform pumping� s1311edin1/U/15) Sampling Event
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4thQtr 12/7/2005
3/9/2006 2nd Otr 6/14/2006 3rd Qtr 7/20/2006 4th Qtr 11/8/2006 1st Ctr 2/28/2007 2nd Qtr 6/27/2007 3rd Otr 8/15/2007 4thQtr 10/10/2007 1stQtr 3/28/2008 2nd Otr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008
3/11/2009 2nd Qtr 6/23/2009
3rd Otr 9/14/2009 4th Qtr 12/29/2009 1stOtr 3/3/2010 2nd Qtr 6/14/2010 3rd Qtr 8/18/2010 4th Qtr 10/15/2010 1stOtr 2/24/2011 2nd Qtr 6/1/2011 3rd Qtr 8/18/2011 4th Qtr 11/29/2011 1st0frl2L __ 112412012 2nd Otr 6/14/2012 3rd Otr 9/28/2012 4th Qtr 10/4/2012 1s1·atr 2/13/2013 2nd Qtr 6/19/2013
3rd Otr 9/3/2013 4th Q1r 11/14/2013 1st Qtr 2/5/2014 2nd Qtr 5/23/2014 3rd Qtr 8/27/2014 4th Qtr ____ 10/29/2014 1stOtr(2\ 3/9/2015 2nd Qtr 6/8/2015 3rd Qtr 8/31/2015 4th Qtr 10/19/2015 1stQtr 3/9/2016 2nd Otr 5/23/2016 3rd Qtr 7/25/2016 4th Qtr 10/13/2016 1statr 3/8/2017 2nd Qtr 6/13/2017
3rd Qtr 7/26/2017 4th Qtr 10/11/2017
2nd Qtr 6/8/2018 3rd Qtr 8/22/2018 4th Qtr 10/22/2018 OWMRC solit sam le 1statr 3/8/2019 2nd Qtr 6/5/2019
3rd Otr 9/4/2019 4thQtr 12/10/2019 1stQtr . 2/19/2020 2nd Otr 5/27/2020 3rd Qtr 9/4/2020 4thQtr 10/28/2020 1stOtr 2/23/2021 2nd Qtr 6/9/2021
3rd Qtr 8/24/2021 4thQtr 12/1/2021 1stQtr 3/9/2022 2nd atr 6/8/2022 3rd Qtr 8/30/2022 4thQtr 11/30/2022 1statr 3ni2023
15 ua/L) NA NA <10 <50 <50 <50 <50 1.4 1.2 1.4 1.3 1.3 1.3 1.1 1.3 1.3 1.1 1 <1.0 <1.0 <1.0 1.2
1 <1.0 <1.0
<1.0 <1.0 <1.0 ---------<1.0 <1.0 <1.0 3.66 <1.0 <1.0 <1.0 5.47 4.77 <1.0 <1.0 ---------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <7.6 <1.0 <1.0 ----
<1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
170 µa/LI 2,700
3,080 2,900 2.400 2,700 2,200 2,840 2.260 1,900 1,900 2,300 2.000 2.000 1,900 1.700 1.700 1.700 1.500 1.700 1.400 1,300 1,600 1.600 1.500 1.300 1.200 1.300 1,500 1.300
1,000 1.100 1,320 1.100 1,150
1,280 1,090 1,020 845
1,130 1,260 1,060 1,040
1,140 1.160 1,330 519 977 958 556 810 70.4
1.010 752 210 87.2 1,040 894 1,070 1,190 499 1,060 924 �8 957 821 957 946 914 954 1,010 928 {1) As of March 2012 both north and south WIid Ide ponds no loog!r rece!""'il water (2) TW4-1 converted to a chloroform pu�!'.'9 �Ustarted in 1114115
j3) chloroform pump•n,1 weH TW4-41 started tn MatJ018 __ • NA = not analyzed Shaded indicates concentrations exceeding GWQS. Bold and italics indicates the MOL exceeded the GWQS. J = Approximated value
DUSA White Mesa Mill
Parameter
Chloromethane Methylene Chloride
130 ua/LI (5 µg/L) NA NA NA NA <10 <10 <50 <50 <50 <50 <50 <50 <50 <50 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T_o------<1.0 <1.0 <1.0 <1.0 <1�o <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.4 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <12 -<1.0 <T.o------
<1.0 <1.0 <5.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.18 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 ________ <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 23 J <1.0 <1.0 ------
<1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS (mail) NA NA NA 52 49 48 51 47 47 45 43 43 39" 39
35 41 37 37 36 41 35 40 35 40 41 35 36 40
42
39 40
37.6
39.1
37.6 36.5
38.9
37.4 38 --------38.I
38.3 40.3 45.9
38.5 41,7 44.4 44.7 44.2 41.5 41.8 42.8 38.5 42 --------45.1!_ 42.0 47.3 43.2 NA 40.9 44.8 46 44.2
46.4 43.7 41.9 45.4 37.2 44.8 45.5 42.6 45.5 45.1
38.3 43.8
Nitrate, Nitrate + Nitrite I10mg/LI 9.1 10.6 9.8 9.7 9.4 9.6
9.2 8.9 9 8.4 7.8 7.6 8.68 8.15 9.3 7.5 6.9 7.3 6.8 7.1 6.8 6.7 6.6 6.6 6.6 6.8 6.6 ----------fa.8 7.1 5.0 6.5 6.99 6.87 7.12 7.08 7.74 6.93 4.80 ----------6�31 7.06 6.07 6.28
1.55 0.148 0.138 5.49 0.746 4.44 5.74 5.04 5.78 0.17
----------4.84 4.38 4.30 4.57 0.46 4.51
1.43 1.65 3.91 4.67 0.44 2.22 4.30 2.72 0.73
1.38 4.37 3.90 0.18 0.42
3.62
1.71
TABLE 1 (5 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-2 (chloroform pumping well s1aning1/14/15) Sampling Event
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4th Qtr 1217/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rdQtr 7/20/2006 4thQtr 11/8/2006 istQtr 2128/2007 2nd Qtr 6/27/2007 3rdQtr 8/15/2007 4thQtr 10/10/2007 1stQtr 3/28/2008 2nd Qtr 6/25/2008 3rdQtr 9/10/2008 4thQtr 10/15/2008 11/18/2008 1stQtr 3/11/2009 2nd Otr 6/23/2009 3rd Qtr 9/14/2009
4thQtr 12129/2009 1stQtr 3/3/2010 2nd Otr 6/14/2010 3rd Qtr 8/18/2010
4thQtr 10/15/2010 1stQtr 2124/2011 2nd atr 6/212011 3rd Qtr 8/17/2011 4th Qtr 11/29/2011 lsfaiTf2) 1/24/2012 2nd Qtr 6/14/2012 3rd atr 9/412012 4th Qtr 10/4/2012 1statr 2113/2013
Carbon Tetrachloride (5µg/L) NA NA
2.3 1.8 2.5 2.2 2.1 2.3 2.2 2.4 NA 2.4 2.2 2 2 2 2 2.6 2.5 2.1 2.4 2.2 1.6 2.8 2 2.1 1.8 2 5.17
Chloroform (70 µg/L) 3,700 3,750 3,900 3,500 3:soo 3,200 4,120 3,420 2,300 3,000 340 3,200 3,300 3,100 2,800 #N/A 3,200 3,100 2,800 3,000 1,600 ··2.soo 3,300 3,300 3,000 3100 3,000 2.400 3,900 2,500
2,900 _3,100 3,580
OUSA White Mesa Mill
Chloromethane
(30 ug/LI NA NA <10
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ______ <1.0 <1.0 <1.0
Parameter IGWQSI Methylene Chloride (5 µc/L) NA NA
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 -----
<1.0 <1.0 <1.0 2nd Qtr 6/19/2013 2.65 3,110 2 <1.0 3rd atr 9/3/2013 4th Qtr 11/14/2013 1stQtr 216/2014 2ndQtr 5/23/2014 3rdQtr 8/27/2014 4th Qtr 10/30/2014 1st atr (2) 3/9/2015 2ndQtr 6/812015 3rd atr 8/31/2015 4thQtr 10/19/2015 1stQtr 3/9/2016 2nd Qtr 5/23/2016 3rdQtr 7/25/2016 4thQtr 10/1212016 1stQtr 3/8/2017 2ndatr 6/13/2017 3rdQtr 7/26/2017 4thQtr 10/11/2017
1statr 3/12/2018 2ndQtr 6/8/2018 3rdatr 8/2212018 4thQtr 10/2212018 1stQtr 3/8/2019 2ndQtr 6/5/2019 3rd Qtr 9/4/2019 4th Qtr 12110/2019 1stQtr 2119/2020 2nd atr 6/10/2020 3rd Qtr 9/4/2020 4thQtr 10/28/2020 1stQtr 2123/2021 2nd Qtr 6/9/2021 3rd atr 8/24/2021 4th Qtr 1211/2021 1stQtr 3/17/2022 2nd atr 6/8/2022 3rd atr 8/30/2022 4th Qtr 11/30/2022 1statr 317/2023
2.41 3,480 3.15 3,740 7.1 3,180 6.05 2,930 1.4 3,170 2.6 3,580 1.44 <1.0 1,650 <1.0 1,060 2.6 2,070 1.2 1,970 1.49 2,070 <1.0 1,780 <1.0 1,600 <1.0 i.570 <1.0 1,940 <1.0 1,310 <1.0 1,610 <19 1.200 <19 1,200 <1.0 764 <1.0 949 <1.0 980 <1.0 822 <1.0 1,040 <1.0 1,360 <1.0 797 <1.0 934 <1.0 1.880 <1.0 1,070 <1.0 1.260 <1.0 1,130 <1.0 939 <1.0 1,160 <1.0 1,150 <1.0 852 <1.0 1,020 <1.0 892 <1.0 832 <1.0 1,030 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 3.6 <1.0 <1.0 <1.0 <T_o------<1.0 -----
<1.0 <1.0 2.6 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <30 68 J <30 60 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS (mg/L)
NA NA NA 56 56 56 54 55 54 50 49 51 48 46 42 47 NA 46 44 43 46 42 43 43 41 46 42 48 49 49
52 76 49 46 46.9 44.9 43.9
45,9
45.4 45
45.5
44.9 48.1 50 41.9
4':i:4 43.8
42.9 44.3 43.1 43.6 43.2 43.5 44 43
44.4 41.3
44.3 41.7 40,4 39.8 40.8 41.5 42.1 40.6 41.3 38.7 43.3 32.5 36.8 41.9 36.7 39.5 40.7 35.5 41.4
Nitrate, Nitrate + Nitrite 110 mg/LI 7.7 8.6 8.0 7.8 7.5 7.1 7.4 7.6 7.3 7.8 7.3 6.9 6.9 7.4 7,1 8.0 #NIA 6.5 6.4 6.6 6.4 6.8 8.7 6.6 6.5 7.0 6.8 6.0 7.0
7.7 4.0 7.6 8.1 7.51 9.3 8.39 7.87 9.11 6.2
----------8�45 5.32 4.3 3.76 5.18 5.30 5.67 4.07 6.07 4.74 4.90
5.08 3.25 4.00 5.00 2.94 3.50 4.83 3.52
4.38 4.79 3.40 6.07 3.62 3.35 2.34 3.30 3.89 1.97 3.49
3.1 3.07 3.74 2.03
TW4-3 sampling Event
TABLE 1 (6 of 33) Historic Summary Of MonHoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA WhHe Mesa MIii
Parameter IGWQSl Carbon Tetrachloride Chloroform 15 ua/L) (70 uaJLl Chloromethane 130 �g/Ll Methylene Chloride (5 �g/L) Chloride No GWQS lmalL) Nitrate, Nitrate + Nitrite (10 m•/Ll 1st atr 3/16/2005 NA <1.0 2nd Qtr 5/25/2005 NA <1.0 NA NA NA NA 3rdQtr 8/31/2005 <1.0 <1.0 6.4 <1.0 NA NA NA 4th atr 1217/2005 <1.0 <1.0�--+<_1�.o�----+<�1�.o�-------+------2�6'+-_ 1st Qtr 3/9/2006 <1.0 ·•t:o 2.3 <1.0 26 2nd Qtr 6/14/2006 <1.0 <1.0 1.6 <1.0 26 3rd Qtr 7/20/2006 <1.0 <1.0 2.2 <1.0 26 4th Qtr 11/8/2006 <1.0 <1.0 <1.0 <1.0 23 ,·.ratr 2/28/2007 <1.0 <1.0 <1.0 <1.0 22 2nd Qtr 6/27/2007 <1.0 <1.0 <1.0 <1.0 23 3rd Q1r 8/15/2007 <1.0 <1.0 <1.0 <1.0 24 �: g:; · 1�!���gg� :� g :lf ·· +:���g�----+:���:g�-······························ .... -----���;1----2nd Qtr 6/25/2008 <1.0 <1.0 <1.0 <1.0 19 3rdQtr 9/10/2008 <1.0 <1.0 <1.0 <1.0 19 4th Qtr 10/15/2008 <1.0 <1.0 <1.0 .,-c<�1."'0___ 22 1st atr 3i4i2009 <1.0 <1.0 <1.0 <1.0 21 2nd Qtr 6/23/2009 <1.0 <1.0 <1.0 <1.0 20
3.5 3.7 3.5 3.3 3.3 7.1 2.9 1.5 3:i 3.3 3.1 2.8 Ii 3rdQtr 9/14/2009 <1.0 <1.0 <1.0 <1.0 21 2.8 ��1g:; 1���g�i :1:g :1•g :�:g :1 g ��•!-------�: 2nd atr 6/14/2010 <1.0 <1.0 <1.0 <1.0 24 3.0 3rd Qtr 8/10/2010 <1.0 <1.0 <1.0 <1.0 22 3.1 t�g:; 1t�:;�g:y::g ::g --+-':]'-'g'.'------1:'-':'cg�----�� ················································�:�2nd Qtr 5/25/2011 <1.0 <1.0 <1.0 <1.0 23 3.7 3rd atr 8/17/2011 <1.0 <1.0 <1.0 <1.0 23 4.0 t;� g:� 12) 1 :::;�gg =� g =� g ·]J-g�----+:���g�------+_-_-_-_-_-_-_-_-_����'+----_-_-_······_·······_·······_-_-_-_-_�7=:�' 2ndQtr 5/31/2012 <1.0 -<1.0 -<1.0 <1.0 -24 4.4 3rd Qtr 8/28/2012 <1.0 <1.0 <1.0 <1.0 25 4.9 4th Qtr 10/3/2012 <1.0 <1.0 <1.0 <1.0 25 4.8 isiair 21712013 <iii <t.o <1.0 .. . •iii 23.7 5.05 2nd atr 6/28/2013 <1.0 <1.0 <1.0 <1.0 23.8 5.83 3rdQtr 9/3/2013 <1.0 <1.0 <1.0 <1.0 25 4.90 4thQtr 11/8/2013 <1.0 <1.0 <1.0 <1.0 24.J.�----..................... 5.�� ,·.i--atr 11221201·4 ·.1:o····· <1.0 <1.0 <1.0 24.9 6.66 2nd Qtr 5/21/2014 <1.0 <1.0 <1.0 <1.0 24.4 6.01 3rd atr 8/13/2014 <1.0 <1.0 <1.0 <1.0 26 5.30 4th Qtr 10/23/2014 <1.0 <1.0 <1.0 <1.0 26.7 6.07 ·,,fatr 3/1 ti2ois <1.0 · .. -;-:o <1.0 <1.0 26.2 6�4 2nd Qtr 6/10/2015 <1.0 <1.0 <1.0 <1.0 27.5 5.71 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 27.5 3.94 3rd Qtr 8/13/2015 <1.0 <1.0 <1.0 <1.0 27.4 3.88 t�g:; 1�!�!�g1� �1g :�:g 11·'.g �1--g'.'--------l------"��"'6"-8f-------"::"'!.!.J�I 2nd Qtr 5/25/2016 <1.0 <1.0 <1.0 <1.0 27.9 5.65 3rdQtr 7/27/2016 <1.0 <1.0 <1.0 <1.0 26.5 6.10 4thQtr 10/19/2016 <1.0 <1.0 <1.0 <1.0 ..• ?M. 6.99 ist Qtr 3/14/201.7 <1.0 <1.0 ·•fo··· <1.0 28.1 6.18 2nd Qtr 6/14/2017 <1.0 <1.0 <1.0 <1.0 28.7 6.36 3rd atr 7/27/2017 <1.0 <1.0 <1.0 <1.0 28.5 6.36 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 28.9 6.24 114thQtr 10/11/2017 <1.0 <1.0 ............ <1.0 <1.0 25.9 6.32 u1st atr 3/i4i:fo°i8 <1.0 <1:0 <1.0 <1.0 29.8 · ··1f45 OuplicatelW4-65 <1.0 <1.0 <1.0 <1.0 29.5 6.31 112nd Qtr 6/8/2018 <1.0 <1.0 <1.0 <1.0 26.1 6.52 3rd atr 8/29/2018 <1.0 <1.0 <1.0 <1.0 31.0 5.53 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 31.0 5.44 j4thQtr 11/30/2018 <1.0 <1.0 <1.0 <1.0 27.4 5.85 Duplicate TW4-65 ..... ::JJ) <1.0 <1.0 <1.0 26.2 5.77 1s1 atr 3/13/2019 <1.0 <1.0 ············ ·•°i.O <1.0 25.5 5-:ii:i 2nd Qtr 6/13/2019 <1.0 <1.0 <1.0 <1.0 27.4 6.68 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 25.9 6.60 3rd Qtr 9/11/2019 <1.0 <1.0 <1.0 <1.0 26.0 5.12 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 22.1 5.76 t: g:; 1��t�i1i :i,g :� g -+::..c�"":g'----+:°"�"'g-----+-----�2�J:�'l----------'t�l Duplicate TW4-65 <1.0 <1.0 <1.0 <1.0 26 6.38 2nd Qtr 6/10/2020 <1.0 <1.0 <1.0 <1.0 26.2 6 .53 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 26.7 6.63 3rd Qtr 9/17/2020 <1.0 <1.0 <1.0 <1.0 25.9 6.36 4th Qtr 11/4/2020 <1.0 �.1...9.... <1.0 <1.0 24.9 6.02 1stQtr .... . .. iii?/2021 <1.0 <1.0 <1.0 <io··· 28.4 6.19 Duplicate TW4-65 <1.0 <1.0 <1.0 <1.0 27.6 6.64 2nd Qtr 6/15/2021 <1.0 <1.0 <1.0 <1.0 27 8.04 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 23.9 7.89 3rd Qtr 9/15/2021 <1.0 <1.0 <1.0 <1.0 20.3 5.28 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 20.7 6.19 4thQtr 1217/2021 <1.0 <1.0 <1.0 <1.0 26.2 5.97 ��J��eTW4�5 3/15/2022 -:l�g.. :�:g :l'.g :�:g -��'.�6i.� 2nd Qtr 6/15/2022 <1.0 <1.0 <1.0 <1.0 26.7 5.8 3rd Qtr 9/13/2022 <1.0 <1.0 <1.0 <1.0 27.3 5.47 t��g:; 1�'.�1§i Hg�------,�;g H& :;g �6� 6s� NA = not analyzed Shaded indicates concentrations exceedmi:i GWQS.
TABLE 1 (7 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-4 (chlofoform pumping well llaredin111q1r2010) Sampling Event
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rdQtr 8/31/2005 4thatr 12/7/2005 1stQtr 3/9/2006 2nd at, 6/14/2006 3rdatI 7/20/2006 4thatr 11/8/2006 1stQtr 2/28/2007 2nd at, 6/27/2007 3rdOtr 8/15/2007 4thatr 10/10/2007 1stQtr 3/28/2008 2nd atr 6/25/2008 3rdatI 9/10/2008 4thatr 10/15/2008 1stQtr 11/18/2008 1statr 3/4/2009 2nd atr 6/23/2009 3rdQtr 9/14/2009 4th atr 12/29/2009 1statr(2) 2117/2010 2nd Qtr 6/14/2010 3rdatr 8/10/2010 4thatr 10/15/2010 1stQtr 2/23/2011 2nd atr 6/1/2011 3rdQtr 8/17/2011 4thatr 11/16/2011 lsfOtr 111 1/23/2012
2nd atr -6/6/2012 3rdOtr 9/4/2012 4thatr 10/3/2012 1statr 2/11/2013 2nd Qtr 6/29/2013 3rdatr 9/3/2013 4thatr 10/23/2013 1stOtr 1/27/2014 2ndatr 5/19/2014 3rdOtr 8/11/2014 4th atr 10/21/2014 1statr(4) -3/9/2015 2ndatr 6/10/2015 3rdOtr 8/31/2015 4th atr 10/19/2015 1stQtr 3/9/20fo 2nd atr 5/23/2016 3rd Qtr 7/27/2016 4th atr 10/13/2016 1st Ctr 3/8/2017 2nd atr 6/13/2017 3rd atr 7/26/2017 4th atr 10/11/2017 1st atr 3/12/2018 2nd atr (3) -6/8/2018 3rd Otr 8/22/2018 4th atr 11/28/2018 1st0tr 3/8/2019 2nd Qtr 6/5/2019 3rd atr 9/4/2019 4th atr 12/10/2019 1statr 2/19/2020 2nd atr 5/27/2020 3rd atr 9/4/2020 4th atr 10/28/2020 1stOtr 2/23/2021 2nd Otr 6/9/2021 3rd Qtr 8/24/2021 4thatr 12/1/2021 1stQtr 3/9/2022 2nd atr 6/8/2022 3rd Qtr 8/30/2022 4thatr 11/30/2022 1statr 3nt2022
Carbon Tetrachloride 15 ua/Ll NA NA
1.7 1.5 1.7 1.5 1.5 1.6 1.5 1.4 NA <2.0 1.2 1.2 1.1 1.1 --------1 1.2 1.3 1.3 1.4 1.2 <1.0 1 <1.0 <1.0 ----1.2 1 1 <1.0 1.2 5.3 3.88 4.94 4.94 <1.0 1.05 <1.0 <1.0 <1.0 <1.0 1.21 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloroform 170 µg/Ll 3.100 2.400 3,200 2,800 2,900 2,600 2,850 2.670 2.200 2.400 2.700 2.500 2,800 2.500 2,200 #NIA 2,500 2.200 1.800 2,000 950
1.700 2.100 1.700 1,800 1.700 1,500 1,500 1,200
1,600 1,400 1.460 1.330 1,380 1.360 1.260 1.220 1,320 1,130
1,280 1,220 1,190 1,190 1,780 1,380 1.430 1�290 1.290 1,290 1,120 1,160
1.030 1,140 1.050 1,070 989 1,140 1,100 1,140 1.110 979 1,13-0 1,240 1,100 950 1.010 1,110 1.040 1030 945 (1) As of March 2012 both north and south wild hfe ponds no lona!'r receMn,.il water J2) TW4-4 converted to a Chloroform .e.umprna.,well stared in 1&'._Str 2010 ---· j3) TW4.-41 installed as a Chloroform pumprna.well stared In Mat_2018 ----· (4) TW4-2 converted to a chloroform pumPf!lQ_!llell started m 1114/15 _____ _ NA and #N/N,for graph use)= not analyzed Shaded indicates concentrations exceeding GWQS. Bold and Italics indicates the MDL exceeded the GWQS.
DUSA White Mesa Mill
Chloromethane 130 ua/Ll NA NA <10
<50
<50 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T.o------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Parameter IGWQSl Methylene Chloride (5 ug/L) NA NA
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 7.1 <1.0 <1.0 <T.o------<1.0 1.72 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T.□<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 ------<1.0 <1.0 <1.0 <1·.-0--
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS (mg/Ll NA NA NA 54 51 48 50 49 49 47 45 47 43 42 39 44 NA 37 34 39
_________ ;!1, 48 35 36 38 41 35 40 39
_________ )8 43 39 38 39 39.6 38.8 43.9 37.4 47.5 40
37.6 41.3 45.8 38.5 39.7 41.9 40.2 40.3 41.7 40.7 40.5 40.7 --------42.2 39.0 44.6 41.4 38.3 38.5 39.4 40.4 43.4 46.1 40.0 38.6 39.8 39.4 39.6 42.5 37.1 39.9 41.0 29.6 30.2
Nitrate, Nitrate + Nitrite (10 mg/L) 10.0 11.3 9.9 10.2 9.5 8.6 9.7 10.1 9.0 9.4 9.5 9.5 9.2 10.8 8.8 10.1 #N/A 10.2 8.2 8.4
6.6 7.6 7.3 7.1 7.ci 7.0 6.6 7.0
7.1 7.1 7.0 7.36 6.30 7.22 7.84 7.28 5.91 5.3
7.7 6.33 6.45 6.27 6.7 6.56 7.22 6.77 6.87 7.06 6.47 6.90
----------6)_;: 6.34 6.10 6.02 7.26 10.40 6.32 6.52 4.58 7.26 7.04 6.77
9.02 4.00 7.32 6.6 6.0 6.65 6.59 7.12
1st Qtr 3/16/2005 NA 2nd Qtr 5/25/2005 NA 3rd Qtr 8/31/2005 <2.5 4th Qtr 12/7/2005 <2.5 1st Qtr 3/9/2006 <2.5 2nd Qtr 6/14/2006 <2.5 3rd Qtr 7/20/2006 <1.0 4thQtr 11/8/2006 <1.0 i-stOtr 2128/2007 <1.0 2nd Qtr 6/27/2007 <1.0 3rd Qtr 8/15/2007 <1.0 4th Qtr 10/10/2007 <1.0 1st Qtr 3/28/2008 <1.0 2nd Qtr 6/25/2008 <1.0 3rd Qtr 9/10/2008 <1.0 4th Qtr 10/15/2008 <1.0 1st Qtr 3/4/2009 <t.0 2nd Qtr 6/23/2009 <1.0 3rd Otr 9/14/2009 <1.0 4th Qtr 12/29/2009 <1.0 tst Qtr 2/25/2010 <1.0 2nd Qtr 6/14/2010 <1.0 3rd Qtr 8/11/2010 <1.0 4th Qtr 10/15/2010 <1.0 tstQtr 212212011 <1.0 2nd Qtr 5/26/2011 < 1.0 3rd Qtr 8n/2011 <1.0 4th Qtr 11/16/2011 NA
rsTTitr(w 2nd Otr 6/6/2012 <1.0 3rd Qtr 9/11/2012 <1.0 4th Qtr 10/4/2012 <1.0 1stQtr 2113/2013<1.0 2nd Qtr 6/1312013 <1.0 3rdQtr 9/5/2013<1.0 4th Qtr 11/13/2013 <1.0 1st Qtr 1/30/2014 <1.0 2nd Qtr 5/2212014 <1.0 3rd Otr 8/14/2014 <1.0 4th Qtr 10/13/2014 <1.0 1stQtr 3/12/2015 <1.0
Duplicate TW4-70 <1.0 2nd Qtr 6/10/2015 <t.0 3rdQtr 9/10/2015 <1.0 4th Qtr 10/28/2015 <1.0 tstQtr ·3/17/2016<1.0 2nd Qtr 5/23/2016 <1.0 3rd Qtr 8/3/2016 <1.0 4thQtr(3) 10/26/2016 <1.0
D�JicaleTW4-75 _____ <1.0 _ _ __ _ 1st Qtr 3/15/2017 <1.0 2nd Qtr 6/15/2017 <1.0 3rd Qtr 8/8/2017 <1.0 4th Qtr 10/11/2017 <1.0
DWMRC snlit sam le <0.19 3/12/2018 2ndQtr 6/13/2018 <1.0
3rd Ctr 8/30/2018 <1.0
Dupicate TW4-70 4thOtr 11/28/2018
DuPkate f\N4-70 3/16/2019 6/13/2019 9/11/2019
TW4-70 12114/2019
TW4-70 <1.0 3/17/2020 TW4-70 6/11/2020 3rdOtr 9/18/2020
Chloroform Chloromethane
120 NA 113 NA 82 63 66 51
NA NA 5.8 <2.5 2.5 <2.5 3.1 <2.5
NA 3.; NA 6.C 56 6.1 52 6.1 3.1 <2.5 51 5.! 53.7 <t.0 <1.0 54 5_; 47.1 <1.0 <1.0 55 2. 35 <1.0 <1.0 57 7. 26 <1.0 <1.0 45 7. 9.2 <1.0 <1.0 38 7.
11 <1.0 <1.0 36 7. 9.3 <1.0 <1.0 37 8. 11 <1.0 <1.0 34 7. 10 <1.0 <1.0 37 9. 12 <1.0 <1.0 34 7. 13 <1.0 <1.0 37 7. 12 <1.0 <1.0 48 8. 8.5 <1.0 <1.0 41 7. 13 <1.0 <1.0 43 6. 12 <1.0 <1.0 28 7.1 12 <1.0 <1.0 38 7.C 11 <1.0 <1.0 41 7.2 10 <1.0 <1.0 34 7.( 9 <1.0 <1.0 35 7.2 10 <1.0 <1.0 37 7.5 #N/A NA NA 30 6.C
� H-��"'g------l-'-:��g�-----'"'N"'A'------2-2""#�N�/A�-----5-;_-'1 ' 8.4 <1.0 <1.0 ---------------39 -----------
12.0 <1.0 <1.0 37 8.1 8.0 <1.0 <1.0 38 7.7 10.8 <1.0 <1.0 34.3 8.24 11.2 <1.0 <1.0 36.5 10.7( 11.6 <1.0 <1.0 39.1 7.7 14.4 <1.0 <1.0 41.1 7.7 12.5 <1.0 <1.0 40.5 9.1 13.4 <1.0 <1.0 51.4 7.7 12.0 <1.0 <1.0 44 7. 14.6 <1.0 <1.0 45.1 8.3 13.8 <1.0 <1.0 45.1 9.3 13.8 <1.0 <1.0 46.4 8.1 13.3 1.07 <1.0 47.3 7.C 12.9 <1.0 <1.0 52.2 8. 11.0 <1.0'!------+<'-'1"'.0c--____ -+ ______ 4e,3".6cl--------8'"'·""1'1 11.0 <(o <1.o 44.7 10.2 13.6 <1.0 <1.0 45.9 8.! 10.8 <1.0 <1.0 44.6 8. 9.9 <t.o <1.0 47.8 8.: 12.0 <1.0 <1.0 49.5 8. 12.6 <1.0 <1.0 ------44.7 8.4 14.6 <1.0 <1.0 47.3 8.5 14.6 <1.0 <1.0 48.6 8.5 13.8 <1.0 <1.0 42.5 8.5 12 <0.3 <0.32 47 8. 15.2 <1.0 <1.0 51.2 8. 13.9 <1.0 <1.0 47.3 9. 15.4 <1.0 <1.0 54.7 7. 15.3 <1.0 <1.0 55.9 7.: 15.6 <1.0 <1.0 49.8 7. 16.2 <1.0 <1.0 48.5 7. 14.1 <1.0 <1.0 47.6 7. 15.8 <1.0 <1.0 49.3 7. 14.6 <1.0 <1.0 46.1 7.0 13.6 <1.0 <1.0 45.8 6.8' 15.7 <1.0 <1.0 53.t 6.97 16.0 <1.0 <1.0 52.5 7.2 14.8 <1.0 <1.0 48.3 7.11 14.8 <1.0 <1.0 48.4 7.72 15.4 <1.0 <1.0 49.5 7.83 14.8 <1.0 <1.0 47.0 6.37 4thQtr 1stQtr 11/4/2020 3/18/2021 !-'!'��R�------+----!;-o!-�.�:+::'-!;�g:----+:':-;";;g'------+------'5�04} 2ndQtr 6/16/2021 3rdOtr 9/2212021 4thQtr 121812021 3/23/2022 2ndOtr 6/16/2022 9/14/2022 4thQtr 2022 023 laboratory missed holding time.
13.0 <1.0 <1.0 50.8 8.1
12.4 <1.0 <1.0 51.3 6.7 11.0 <1.0 <1.0 47.7 7. 10.3 <1.0 <1.0 40.7 7.1 13.2 <1.0 <1.0 45.8 7.2: 7.6 <1.0 <1.0 51.8 7.7 8.6 <1.0 <1.0 51.3 6.
(2) As of March 2012 both north and south "Mid Ide ponds no lon2!!r receM!!i water (3) Chloroform puml?!!'.2_well f\N4-39 started in 11/20/16 --· NA and #N/A(for waphs) = not analyzed Shaded indicates concentrations exceedini:i GWQS.
TABLE 1 (9 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
TW4-o Parameter Sampling Event IGWQSI Carbon Tetrachloride Chloromethane Methylene Chloride
15 ua/LI 170 ug/L) 130 ug/LI 15 ug/Ll 1stQtr 3/16/2005 NA <1.0 NA NA 2nd Qtr 5/25/2005 NA 2.5 NA 3rd Qtr 8/31/2005 <1.0 10 2.8 <1.0 4thQtr 12/7/2005 <1.0 17 1.3 <1.0 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd Qtr 7/20/2006 4th Qtr 11/8/2006 1StOtr 2/28/2007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1stOtr 3/28/2008 2nd Otr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 1stOtr 3/4/2009 2nd Otr 6/23/2009 3rd Qtr 9/14/2009 4th Qtr 12/29/2009 1st Qtr (5) --2/25/2010 2nd Otr 6/14/2010 3rd Qlr 8/11/2010 4th Qtr 10/15/2010 1st Ctr 2/22/2011 2nd Otr 5/26/2011 3rd Qtr 817/2011 4th Qtr 11/16/2011 (1) 12/7/2011 (2) 11/16/2011 11st ulr(4) 1/18/2012
2nd Qtr 6/6/2012 3rd Qtr 9/11/2012 4th Olr 10/4/2012 1stQtr 2/13/2013 2nd Qtr 6/13/2013 3rd Qtr 9/5/2013 4thQtr 11/13/2013 1st atr 1/29/2014
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 ----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <1.0 <1.0 <1.0 <1.0------<1.0 <1.0
<1.0 <1.0 <1.0 <1.0
31 <1.0 19 <1.0 11 <1.0 42.8 <1.0 46 <1.0 11 <1.0 18 <1.0 18 <1.0 52 <1.0 24 <1.0 39 <1.0 37 <1.0 81 <1.0 120 <1.0 280 <1.0-250 <1.0 ----1000 <T.O ______
590 <1.0
630 <1.0 420 <1.0 47 <1.0
9.6 <1.0 16 <1.0 #N/A NA 21 <1.0 50 <1.0 38 <1.0
-----4'1 <T.O ______
6.9 <1.0
9 <1.0
6.89 <1.0 4.86 <1.0 5.93 <1.0 5.51 <1.0 5.7 <1.0 10.3 <1.0 2nd Qtr 5/22/2014 <1.0 3rd Qtr 8/14/2014 (3) 9/24/2014 4thQtr 10/29/2014 1stQtr 3/12/2015 2nd Qtr 6/10/2015 3rd atr 9/10/2015 4thOtr 10/29/2015 'istQtr 3/22/201-6 2nd Qtr 6/8/2016 3rd Otr 7/27/2016 4thQtr 10/26/2016 1stQtr 3/16/2017 2nd Qtr 6/21/2017 3rd Qtr 8/8/2017 4thQtr 10/11/2017 1st Qtr 3/20/2018
<1.0 202 <1.0 <1.0 260 <1.0 <1.0 723 <1.0 <1.0 1,180 <1.0 <1.0 1.040 <1.0 <1.0 1,040 <1.0 <1.0 843 <1.0 <1.0 834 <1.0 <1.0 486 <1.0 <1.0 433 <1.0 <1.0 301 <1.0 <1.0 288 <1.0 <1.0 239 <1.0 <1.0 129 <1.0 <1.0 121 <1.0 159 <1.0 2nd Qtr (6) 6/14/2018 <1.0 ------------74'11 <T.o------3rd Qtr 9/5/2018 <1.0 4thQtr 12/12/2018 <1.0 1stQtr 3/19/2019 <1.0 2nd Otr 6/13/2019 <1.0 3rd Qtr 9/11/2019 <1.0 4thOtr 12/14/2019 <1.0 1s1Qtr 3/17/2020 <1.0 2nd Qtr 6/11/2020 <1.0 3rdQtr 9/18/2020 <1.0 4thQtr I 1/4/2020 <1.0 1stQtr 3/18/2021 <1.0 2nd Qtr 6/16/2021 <1.0 3rdQtr 9/15/2021 <1.0 4thQtr 12/8/2021 <1.0 1stQtr 3/22/2022 <1.0 2nd Otr 6/16/2022 <1.0 3rd Otr 9/14/2022 <1.0 4thOtr 12/8/2022 <1.0 1stQtr 3/29/2023 <1.0 (1) voes were res am pied because laboratory missed holding time. (2) Results of the TW4•70 the duplicate sample for TW4-6. (3) Reanalyzed for voes only.
53.2 <1.0 37.0 <1.0 23.2 <1.0 15.8 <1.0 15.8 <1.0 7.4 <1.0 6.93 <1.0 4.9 <1.0 3.6 <1.0 4.61 <1.0 3.78 <1.0 2.9 <1.0 3.71 <1.0 3.92 <1.0 3.10 <1.0 2.1 <1.0 3.90 <1.0 1.50 <1.0 1.70 <1.0
(4) As of March 2012 both north and south wild kfe £._Onds no l�"S!'' receM� water (� ehloroform_eum,£..ln.Jl well TW4-4 stared m 1st qtr 2010 _ -· JS) Chloroform _eum.e,m,i weU TW4-41 mstalled M_ay ]018 __ • NA and #N/A(for graphs) = not analyzed Shaded indicates concentrations eKceeding GWQS.
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <1.0 <1.0 <1.0 <1.0 ------
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ________
<1.0 <1.0 <fo <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS lma/L) NA NA
32 31 30 37
65 32 38 36 35 33 35 35 33 35 37 37 41 ---------45 33 31 41 40 42 39 36 NA 33 38 ---------40 21 41 40.4 37.9 40.6 40.2 40.6 37 40 NA 41.1 41.2 41.6 47 40.2 42.3 44.1 42.2 46.1 42.1 42.6 42.9 37.6 43.1 40.2 44 20.0 41 38.1 39.7 45.7 43.2 42.4 40.5 42.9 41.6 43.8 34.1 44.8 31.5 43.1 38.7 40.7 43.2
Nitrate, Nitrate + Nitrite 110 mg/LI 0.2 0.4 0.8 0.9 1.2 1.0 0.6 1.4 1.8 0.6 0.7 0.8 1.1 0.9 1.1 1.0 2.2 2.7 5.0
1.8 2.5 3.9 4.3 0.7 0.3 0.3 0.8 #N/A 0.8
0.2 0.1 0.2 0.2 0.2 0.2 1.5 0.2 0.3 4.2 #N/A
6.9 5.3 5.9
6.8 5.6
6.79 3.19 3.85 3.74 3.15 2.42 1.71 1.71
----------1�96 1.48 1.18 0.90 0.755 0.484 0.412 0.244 0.222 0.205 0.144 0.197 0.205 0.215 0.166 <0.100 0.1 0.21 0.144 0.134 <b.1
TABLE 1 (10 of 33)
Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill
TW4-7
Sampling Event
Parameter
fGWQSI
1stOtr 2nd Qtr 3rd Qtr 4th Qtr 1st Qtr 2nd Qtr
3rd Qtr 4th Qtr 1st Ctr 2nd Qtr 3rd Qtr 4th Qtr 1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride Nitrate, Nitrate + Nitrite
(5 ug/L) (70 uo/Ll (30 uo/Ll (5 ug/Ll No GWQS (mn/LI 110 mg/LI 3/16/2005 NA 3,100 NA NA NA 5.2 5/25/2005 NA 2,700 NA NA NA 5.4 8/31/2005 <10 3,100 <10 <10 NA 5.2 12/7/2005 <50 2,500 <50 <50 52 5.3 3/9/2006 <50 1,900 <50 <50 48 1 6/14/2006 <50 2,200 <50 <50 47 4.5 7/20/2006 <50 2,140 <50 <50 51 4.7
��:;�g� ) � �.��g :--�� •"'g----+:)""•'c-g------+--------":"'�1--------4"'."l:I 6/27/2007 1.5 2,600 <1.0 <1.0 45 5.1 8/15/2007 1.4 2.300 <1.0 <1.0 44 4.7 10/10/2007 1.2 1,900 <1.0 <1.0 45 4.7 3/28/2008 1.3 2,200 <1.0 <1.0 43 4.2 6/25/2008 1.3 1.800 <1.0 <1.0 43 4.8 9/10/2008 1.4 1,600 <1.0 <1.0 35 4.16 10/15/2008 NA #N/A NA NA 40 4.01 11/18/2008 <2.0 2,500 .�.i-c,co ____ +<2,e,'c-0 _____ --+'-'Ne;A,__ ____ =l'#"'Ne.c/A.,_ _____�I 1st Qtr 3/11/2009 ......... 1.2 1,800 <1.0 <1.0 35 3.7 2nd Qtr 6/23/2009 <1.0 1.400 <1.0 <1.0 37 3.8 3rd Qtr 9/14/2009 1 1,500 <1.0 <1.0 37 4.1 4th Qtr 12/29/2009 <1.0 1.300 <1.0 <1.0 37 4.2 1st Qtr 2/25/2010 <1.0 1.200 <1.0 <1.0 35 3.8 2nd Qtr 6/14/2010 <1.0 1.100 <1.0 <1.0 31 3.9 3rd Qtr 8/11/2010 1 1,500 <1.0 <1.0 36 3.9 4th atr 1011512010 <1.0 1.1ool-'<'-'1"c.o'-----+•-'-1."'0 _____ 4-_____ _,3""8+-------��41 1st Qtr 2/23/2011 <1.0 1.300 <1.0 <1.0 45 3.6 2nd Qtr 6/112011 <1.0 1,200 <1.0 <1.0 35 4.0 3rd Qtr 8/18/2011 <1.0 1.200 <1.0 <1.0 37 4.1
I�;� g:; (1) 1 ;;���iH �H 1 000 <1.0 <1.0 37 3.8
2ndOtr 6/14/2012 <1_0-----___ J.��� =�� =�� ---------------li ----------· }� 3rdQtr 9/13/2012 <1.0 870 <1.0 <1.0 40 3.8 4th Qtr 10/4/2012 <1.0 940 <1.0 <1.0 41 3.8 1st Qtr 2/13/2013 <1.0 940 <1.0 <1.0 37.7 3.51 2nd Qtr 6/18/2013 <1.0 953 <1.0 <1.0 39.3 4 3rd Qtr 9/12/2013 <1.0 1,040 <1.0 <1.0 36.4 4.17 4thQtr 11/14/2013 <1.0 1,050 <1.0 <1.0 37.2 ........... 4.13 1stQtr 2/5/2014. 5.41 946 <1.0 <1.0 38.2 4.24 2nd Qtr 5/22/2014 4.78 847 <1.0 <1.0 37.7 4.19 3rd Qtr 8/27/2014 <1.0 857 1.5 <1.0 39 2.9 4th Qtr 10/30/2014 <1.0 926 <1.0 <1.0 ________ 40." __________ 3A!! 1stQtr(2) 3/18/2015 <1.0---------942 <1.0 <1.0________ 40.4 4.25 2ndQtr 6/11/2015 <1.0 950 <1.0 <1.0 42.1 2.62 3rdQtr 9/10/2015 <1.0 897 <1.0 <1.0 46.7 4.72 ;��g:; 1�:���g1-� �H=-------+ .. ········--':";-'-:l-':'-')"'g----+:"")"'g-----+-----�:�'.? ··· 1:� 2nd atr 6/8/2016 <1.0 909 <1.0 <1.0 44.1 ____ 3.75 3rd Qtr 8/4/2016 <1.0 1,000 <1.0 <1.0 42.3 4.21 4thQtr 10/26/2016 <1.0 886 <1.0 <1.0 45.8 4.33 1stQtr 3/21/2017 <1.0 986 <1.0 <1.0 40.5 3.87 2nd Qtr 6/21/2017 <1.0 968 <1.0 <1.0 43.3 4.15 3rdQtr 8/4/2017 <1.0 1,070 <1.0 <1.0 44.7 4.20 4thOtr 10/11/2017 <1.0 884 <1.0 <1.0 43.7 4.35 DWMRCsplrtsam le <7.6 890 <12 17 J 42.0 4.30 1stQtr 3/21/2018 <1.0 721 <1.0 <1.0 44.5 3.96 2nd Qtr 6/14/2018 <1.0 751 <1.0 <1.0 41.5 4.45 3rd Qtr 9/6/2018 <1.0 781 <1.0 <1.0 48.5 4.34 4th Qtr 12/13/2018 <1.0 838 <1.0 <1.0 42.8 3.98 1st Qtr 3/20/2019 <1.0 736 <1.0 <1.0 41.3 4:01 2nd Qtr 6/19/2019 <1.0 862 <1.0 <1.0 43.0 4.19 3rd Qtr 9/12/2019 <1.0 801 <1.0 <1.0 39.6 3.76 4th Qtr 12/18/2019 <1.0 546 <1.0 <1.0 47.2 3.11 1stQtr 3/18/2020 <1.0 746 <1.0 <1.0 42.1 3.75 2nd Qtr 6/12/2020 <1.0 864 <1.0 <1.0 44.1 4.06
Deplicate TW4-75 3rdQtr 4th Qtr
<1.0 9/19/2020 <1.0 11/11/2020 <1.0 DWMRCs Jitsam le <1�0-------1 i st Otr 3/24/2021 <1.0 2nd Qtr 6/17/2021 <1.0 3rd Qtr 9/23/2021 <1.0 4th Qtr 12/9/2021 <1.0 1stOtr 3/24/2022 <1.0 2nd Qtr 6/22/2022 <1.0 3rd Qtr 9/15/2022 <1.0 4th Qtr 12/9/2022 <1.�.0�------1 1st Otr 3/29/2023 <i".0
871 <1.0 <1.0 43.1 4.19 971 <1.0 <1.0 41.5 3.87 967 <1.0 <1.0 42.8 4.40 930 <20 <20 43 3.90 Bis' <1.0 ·;:·1.0 46.2 4.25 819 <1.0 <1.0 41.7 4.80 801 <1.0 <1.0 42.8 4.58 868 <1.0 <1.0 42.9 3.02 776 2.1 <1.0 41.3 4.1 447 <1.0 <1.0 42.5 3.9 887 <1.0 <1.0 45 3.77 824 <1.0 <1.0 44.8 4.06 619 2.1 <1.0 44.9 3.9
( 1) As of March 2012 both north and south wild life ponds no lon�r receM� water
(2) chloroform pumE!!,n.2,wellS TW4•1 and TW4-2 started 1n 1/14115 -----· NA and #N/Aifor Araphsl = not analyzed Shaded indicates concentrations elo'.ceedinA GWQS. Bold and italics indicates the MDL elo'.ceeded the GWQS. J = Appro1C1mated value
TABLE 1 (11 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
TW4-8 Parameter Sampling Event (GWQS) Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/3112005 4th Qtr 12/712005 1stQtr 31912006 2nd Qtr 611412006 3rd Qtr 7/20/2006 4th Qtr 11/8/2006 1stQtr 2/2812007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th0tr 10/10/2007 1st Qtr 3/28/2008 2nd Qtr 6/25/2008 3rd Otr 9/10/2008 4thQtr 10/15/2008 1statr 3/4/2009 2nd Qtr 6/23/2009 3rd Qtr 911412009 4th Qtr 12/17/2009 1st Ctr 2/2412010 2nd Qtr 6/14/2010 3rdQtr 8/18/2010 4th Qtr 10/15/2010 1st Ctr 2/16/2011 2nd Qtr 5/25/2011 3rdOtr 8/16/2011 4thQtr 11/16/2011 (11 12/7/2011 1st Otr (�j 1118/2012
2nd Qtr 511312012 3rd Otr 8/2912012 4th Qtr 10/3/2012 1stQtr 217/2013 2nd Qtr 5/30/2013 3rdQtr 9/5/2013 4thQtr 11nt2013 1statr 1/23/2014 (2) 2/6/2014 2nd Qtr 5/22/2014 3rd Ctr 8/27/2014 4th Qtr 10/29/2014
NA NA <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
(5 ug/Ll (70 ug/Ll (30 UQIL) 15 ug/Ll 10 NA NA <1.0 NA NA 1.1 1.7 NA <1.0 <1.0 <1.0 1.3 2.1 <1.0 1.8 1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 2.5 <1.0 <1.0 2.5 <1.0 <1.0 1.5 <1.0 <1.0 3.5 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1,0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T.O ____ <T_o------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 63.8 <1.0 <1.0 100 <1.0 <1.0 122 <1.0 <1.0 107 <1.0 <1.0 191 <1.0 <1.0 1st Qtr (4) 3/12/2015 <1.0 ---------<T_o------<1_0--------2nd Qtr 3rd Qtr 4th Qtr 1stQtr 2nd Ctr 3rd Qtr 4th Qtr 1st Qtr 2nd Qtr 3rdQtr 4thQtr ____ DeplicateTW4-75
6111/2015 9/1012015 10/2912015 3/17/2016 6/8/2016 8/4/2016 10/27/2016 3/21/2017 6/21/2017 8/4/2017 10/11/2017
0W¥R_(; __ sp!it sa!_TlpJe 1statr 3/21/2018 Deplicate TW4-75 2nd Otr 6/1412018 3rd Qtr 9/5/2018 4th Qtr 12/1312018 1stQtr 3/19/2019
<1.0 981 <1.0 <1.0 747 <1.0 <1.0 770 <1.0 <1.0 634 <1.0 <1.0 595 <1.0 <1.0 522 <1.0 <1.0 472 <1.0 <1.0 359 <1.0 256 <1.0 <1.0 223 <1.0 <1.0 214 <1.0 <1.0 194 <1.9 230 <1.0 220 <1.0 <1.0 171 <1.0 <1.0 155 <1.0 <1.0 137 <1.0 <1.0 93.8 <1.0 <1.0 103 <1.0 2nd Qtr 6/19/2019 <1.0 96 <1.0 3rdQtr 9/12/2019 Depl�ate TW4-75 4th Qtr 12/18/2019 1st Ctr 3/18/2020 2nd Qtr 6112/2020 3rd Qtr 9/18/2020 4th Qtr 11/11/2020 DeplicateTW4-70
f�i�selitsam 1;/18/2021 2nd Qtr 6/16/2021 3rd Qtr 9/22/2021 Deplicate TW4-70 4th Qtr 12/8/2021 1stQtr 3/23/2022 2nd Otr 6/16/2022 3rdQtr 9/14/2022 4thQtr 12/8/2022 1stQtr 3/29/2023
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <10 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 (1) VOCs were resampled because laboratory missed holding time.
75.4 75.6 84.4 55.0 53.8 39.5 51.3 52.9 50.0 26.9 22.3 17.0 16.4 17.2 15.1 10.9 15.3 4.4 9.1
(2) Resampled to verify chloroform concentration that was collected on 1/23/14 (3) As of March 2012 both north and south wild hfe ponds no lona:r receIvI� water (4)chloroformpumpm2,wells TW4-1 andTW4-2startedm 1/14/15 -----· NA and #N/A(for graphs) = not analyzed Shaded indicates concentrations exceeding GWQS. J = Approximated value
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
H = Sample was analyzed beyond holding times and may not be accureate concentration
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.12 <1.0 4.7 J <3.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride Nitrate, Nitrate + Nitrite No GWQS (mg/L) (10 mg/LI NA <0.1 NA 0.2 NA <1.0 41 <1.0 39 0.3 37 <1.0 39 0.1 40 <.1 39 0.7 42 0.2 42 <1.0 43 0.5 46 0.1 45 <1.0 39 <0.05 44 <0.05 42 <0.1 44 <0.1 44 <0.1 51 <0.1 57 <0.1 42 <0.1 45 <0.1 46 0.1 52 <0.1 45 0.1 46 0.1 45 0.2 NA #N/A 45 0.3 ---------44 0.2 48 0.1 47 <0.1 46.6 0.41 45.5 <0.1 47.5 0.1 46.1 <0.1 48.5 0.166 46.5 0.166 53 0.538 47 0.6 46.7 0.914 49.6 2.3 53 1.88 59.6 1.96 52 2.2 54.2 2.48 58.7 2.14 56.9 2.10 60.1 2.16 ·57.4 58.8 1.97 61.2 1.64 52.2 1.92 56.2 1.71 61 1.90 608 60.8 1.36 53.8 1.31 63.2 1.40 53.1 1.35 54.3 1.23 56.5 1.1 52 0.999 52.5 1.030 60.1 1.21 53.8 1.04 56.9 1.06 52.6 0.894 54.7 1.27 49.9 1.27 56 0.16 H 52.8 1.00 51.5 1.12 40.8 0.665 43.1 0.59 54.9 0.738 50.8 0.8 52.8 0.64 52.5 0.718 50.8 0.654 0.7
TABLE 1 (12 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill
TW4-9 Parameter Sampling Event IGWQSI Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride (5 µg/L) 170 ua/Ll 130 ua/Ll (5 µa/L) 1statr 3116/2005 NA 3.8 NA NA 2nd Qtr 512512005 NA 1.2 NA NA 3rd Qtr 813112005 <1.0 <1.0 2.9 <1.0 4th Qtr 12/712005 <1.0 <1.0 <l.,O <1.0 1stQtr 3/912006 <1.0 <1.0 2.6 <1.0 2nd Qtr 611412006 <1.0 19 2.7 <1.0 3rd Qtr 712012006 <1.0 <1.0 <1.0 <1.0 4th Qlr 111812006 <1.0 <1.0 <1.0 <1.0 1st Ctr 2/2812007 <1.0 <1.0 <1.0 <1.0 2nd Qtr 612712007 <1.0 21 <1.0 <1.0 3rd Qtr 811512007 <1.0 9.5 <1.0 <1.0 4th Qtr 1011012007 <1.0 8.7 <1.0 <1.0 1stQtr 312812008 <1.0 1.3 <1.0 <1.0 2nd Qtr 612512008 <1.0 1 <1.0 <1.0 3rdQtr 9110/2008 <1.0 <1.0 <1.0 <1.0 4thQtr 10115/2008 <1.0 <1.0 <1.0 <1.0 1stQtr 31412009 <1.0 <1.0 <1.0 <1.0 2nd Qtr 612312009 <1.0 <1.0 <1.0 <1.0 3rdQtr 9114/2009 <1.0 <1.0 <1.0 <1.0 4thOtr 12/1712009 <1.0 <1.0 <1.0 <1.0 1stQtr 2/2312010 <1.0 <1.0 <1.0 <1.0 2nd Qtr 611412010 <1.0 <1.0 <1.0 <1.0 3rdQtr 8/1312010 <1.0 <1.0 <1.0 <1.0 4thOtr 1011512010 <1.0 <1.0 <1.0 <1.0 1stQtr 21fmcff1 <1.0 <1.0 <1.0 <1.0 2nd Qtr 512512011 <1.0 <1.0 <1.0 <1.0 3rd Qtr 8/1612011 <1.0 <1.0 <1.0 <1.0 4th Qtr 1111612011 NA NA NA NA
Bl 12/712011 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 lst Otr 111812012 2nd Otr 513112012 <1.0 ---------<1.0 <1.0 <1.0 ------
3rd Qtr 8/3012012 4th Qtr 1013/2012 1stOtr 21712013 2nd Qtr 5130/2013 3rd Ctr 915/2013 4thQtr 11n12013 1st Ctr 112912014 2nd Otr 5122/2014 3rd Qtr 8114/2014 4thQtr 10129/2014 1st Qtr 3112/2015 2nd Qtr 611112015 3rd atr 91312015 4th Qtr 1012812015 1st Otr 311712016 2nd Qtr 6/812016 3rd Ctr 813/2016 4thQtr 1012612016 1st Ctr 3117/2017 2nd atr 6/2112017 3rdQtr 81312017 4thQtr 1011112017 DWMRC snlit sam lo 1stOtr 312112018 2nd Ctr 61412018
91512018
TW4-75 12/1312018 3/1912019 611912019 9/1112019 4th Qtr 12/1812019 1stQtr 3118/2020 2nd Qtr 6112/2020 OeplicateTW4-70 3rd Qtr 911812020 l<th Qtr 1111112020 IOWMRC split sample IDWMRC Oup sample (TW4-81) 1st Ctr 3/1812021 IOephcateTW4-70 12nd Qtr 6/1612021 13rd Qtr 9122/2021 llth Qtr 12/812021 1stOtr 3/2312022 12nd Qtr 6122/2022 13rd Qtr 911412022 IDepk:ateTW4-70 llth Qtr 12/812022
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <{O <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <0.96 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <10 <10 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
312912022 <1.0 TW4-70 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
�
lW4-70 <1.0
were resampled because laboratory missed holding time.
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 6.9 <1.0 47 <1.0 101 <1.0 53.5 <1.0 35.1 <1.0 48 <1.0 68.4 <1.0 74.3 ·c::(O 76.2 <1.0 76.8 <1.0 76.0 <1.0 113 <1.0 113 <1.0 118 <1.0 132 <1.0 120 <1.5 159 <1.0 134 <1.0 132 <1.0 94.2 <1.0 92.4 <1.0 109 <1.0 86.4 <1.0 68.1 <1.0 66.0 <1.0 54.8 <1.0 48.9 <1.0 55.1 <1.0 56.4 <1.0 45.0 <1.0 47.1 <1.0 48.0 <20 46.0 <20 39.0 <1.0 38.2 <1.0 102 <1.0 30.0 <1.0 25.4 <1.0 16.5 <1.0 9.8 <1.0 10.8 <1.0 8.7 <1.0 6.7 <1.0 6.0 <1.0 6.2 <1.0 5.6 <1.0
(2) As of March 2012 both north and south wild ltfe e..onds no lon2;r receM� water NA and #N/A(for Araphs) = not anatvzed Shaded indicates concentrations eKceedinA GWQS J = ApproKimate value
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.6 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS lma/L) NA NA NA 42 38 39 41 44 44 42 38 40 35 35 28 58 30 30 30 37 47 33 40 34 41 38 21 38 NA 28 --------23 22 21 20.6 21.4 22.7 23.6 22 24 27 25 29.5 35.3 39.3 29.2 33�6 35.1 33.6 37.4 34.5 35.9 37 32 35 38.3 35.7 35.2 43.4 42.7 36.3 36.9 38.3 35.2 40.1 37.7 39.5 39.6 36.7 37.2 38 38 40.7 38.7 37.4 30.8 36.9 34.6 41.7 32.4 32.4 33.2 58.5 37.1 36.4
Nitrate, Nitrate+ Nitrite 110 mg/L) 1.3 1.3 1.3 1.3 1.5 1.5 0.9 0.7 0.6 1.3 1.8 2 2.1 2.3 2.79 1.99 2.5 2.3 2.5 1.7 1.4 1.5 1.2 1.8 1.3 3.4 4 2.3 #NIA
4.0 3.9 3.8 4.49 4.49 4.03 4.87 4.36 3.44 2.7 4.29 3.28 1.83 1.44 2.89 2.51 2.16 2.11 2.24 2.18 1.92 1.90 2.18 2.20 1.85 1.85 1.91 1.04 1.11 1.23 1.09 0.785 0.904 0.744 0.855 0.990 1.010 0.867 1.11 0.97 0.97 1.06 1.07 2.0 0.700 0.798 0.80 0.62 0.673 0.660 0.676 0.660 0.765 0.743
TABLE 1 (13 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
,n .. -10 Parameter
Sampling Event IGWQS) Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd atr 8/31/2005 4thQtr 1217/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd atr 7/2012006 4th Qtr 11/8/2006 1stQtr 2/28/2007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1stQtr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 11/18/2008 1stQtr 3/11/2009 2nd Qtr 6/23/2009 3rd Qtr 9/14/2009 4th atr 12/22/2009 1stQtr 3/3/2010 2nd atr 6/14/2010 3rd Qtr 8/12/2010 4th Qtr 10/15/2010 1st Ctr 2/23/2011 2nd Qtr 6/14/2011 rdQtr 8/17/2011 . �th Qtr 11/16/2011 fstCiffll1 111912012
(5ug/L\ NA NA <2.5 <2.5 <5.0 <5.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
(70 ug/L) 130 µo/L) 15 ug/LI 140 NA NA 62 NA NA 110 6.2 <2.5 300 <2.5 <2.5 190 <5.0 <5.0 300 <5.0 <5.0 504 <5.0 <5.0 452 1.6 <1.0 500 <1.0 <1.0 350 <1.0 <1.0 660 <1.0 <1.0 470 <1.0 <1.0 620 <1.0 <1.0 720 <1.0 <1.0 660 <1.0 <1.0 #N/A NA NA 1.200 <2.0 <2.0 1.100 <1.0 <1.0 1.200 <1.0 <1.0 910 <1.0 <1.0 300 <1.0 <1.0 460 <1.0 <1.0 220 <1.0 <1.0 100 <1.0 <1.0 1.100 <1.0 <1.0 620 <1.0 <1.0 280 <1.0 <1.0 180 <1.0 <1.0 110 <1.0 <1.0 76 <1.0 <1.0
2nd Qtr 6/14/2012 <1.0 ------79 <T.O ______ <1.0 ------3rd atr 9/12/2012 <1.0 130 4th Qtr 10/3/2012 <1.0 140 1st Qtr 2/13/2013 <1.0 154 2nd Qtr 6/13/2013 <1.0 486 3rd Qtr 9/12/2013 <1.0 1.126 MhQtr 11/14/2013 <1.0 if16i---· -·--·· 1.380 1statr 1/29/2014 1.260 2nd Qtr 5/23/2014 <1.0 1.110 3rd atr 8/27/2014 <1.0 1.060 4th Qtr 10/30/2014 <1.0 1.220 1stQtr 3/18/2015 <1.0 1.210 2nd atr 6/11/2015 <1.0 1.240 3rd Qtr 9/10/2015 <1.0 1.280 4th atr 10/29/2015 <1.0 1.350 ···---1stOtr 3/22/2016 <1.0 1.430 2nd Qtr 6/812016 <1.0 1.510 3rd Qtr 8/4/2016 <1.0 1.500 ,i+i.. Qtr 10/26/2016 <1.0 1.290 1stQtr 3/2112017 <1.0 ··T260 2nd Qtr 6/21/2017 <1.0 1.140 3rd atr 8/4/2017 <1.0 1.320 4th Qtr 10/11/2017 <1.0 1.150
DWMRC:.�p_lit sam_Ele <9.5 1.100 1stQtr 3/21/2018 <1.0 1,240 2nd Qtr 6/14/2018 <1.0 914 3rd Qtr 9/6/2018 <1.0 911 4th atr 12/13/2018 <1.0 1.070 1stQtr 3/20/2019 <1.0 869 2nd Ctr 6/19/2019 <1.0 799 3rd Qtr 9/12/2019 <1.0 734
4th Qtr 12/18/2019 <1.0 768 1stQtr 3/18/2020 <·ro 798 2nd Qtr 6/11/2020 <1.0 928 3rd Qtr 9/19/2020 <1.0 854 4th Qtr 11/11/2020 <1.0 903 isiatr 3/18/2021 <1.0 718 2nd Qtr 6/17/2021 <1.0 609 3rd atr 9/23/2021 <1.0 545 4th Qtr 12/9/2021 <1.0 675 1st Ctr 3/24/2022 <1.0 471
Deplicate TW4-75 <1.0 456 2nd Qtr 6/22/2022 <1.0 342 3rd Qtr 9/15/2022 <1.0 563 4th Qtr 12/9/2022 <1.0 499 1statr 3/29/2023 <1.0 jfff
(1)p.s of March 2012 both north and south wild life ponds no lon�r rece!VI� water
NA and #N/A(for graphs)= not analyzed
Shaded indicates concentrations exceeding GWQS
J = Approximate value
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.5 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <15 16 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1 <1.0 1 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS lmg/LI NA NA NA 52 50 54 61 58 2 54 59 59 55 58 51 61 NA 64 62 51 51 48 42 38 52 32 42 41 45 40
----46 44 45 49.1 51.5 67.9 70.9 73 77.3 74 75.2 .. 78.6 75 89.5 79.9 84:,· 89.5 85.3 84.4 74.6 73.1 77 70 76 72.7 64.5 75.5 63.5 59.3 58.7 55.8 62 53.5 60.1 53.9 58.6 58.1 48.7 50.6 51.9 46.0 44.8 46.0 52.0 43.4 48.6
Nitrate, Nitrate + Nitrite (10ma/L) 1.E O.E 1.1 3.: 2. 3.t 6.E 5.7 7.3 5.1 7. 6. 7. 9.! 9.23 10.5 #N/A 11.6 9.8 8.1 3.8 5.( 1.E 0.1 11. 9. 3. 1 . 1. 0. 0.8 1.0 1.6 1.2 5.6 13.1
·-·------__ 1§1 16.1 13.! 9.1 13.2 --,Kt 11.4 14.C 13.5 -------------------17. 14.! 14.! 14.1 T:i:o 13.0 13.4 12.9 13.0 __ .. ,,_ 11.1 11.2 10.1 10.1 9.3' 8.86 7.79 6.8f 7.8 8. 7. 8.1 7. 7. 6., 5.4 5. 4. 4. 5.5 4.7 4
TABLE 1 (14 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-11 tchloroform pumping we11 Slarled1l14/15) Sampling Event
1stQtr 3/1612005 2nd Qtr 512512005 3rd Qtr 8/3112005
4th Qtr 12/712005 1st Ctr 31912006 2nd Qtr 6/14/2006 3rd atr 712012006 4th atr 111812006 1stQtr 212812007 2nd Qtr 6127/2007 3rd atr 8/1512007 4th Qtr 10/10/2007 1st Qtr 3/2812008 2nd Qtr 6125/2008 3rd Qtr 9/1012008 4thQtr 10115/2008 11118/2008 1stQtr 3/1112009 2nd Qtr 612312009 3rd Qtr 911412009 4thQtr 1212212009 1stQtr 31312010 2nd Qtr 6114/2010 3rd Qtr 8/1212010 4th Qtr 1_0115/2010 1st Qtr 2123/2011 2nd Qtr 6/112011 3rd Qtr 811712011 4thQtr 11/1612011 112412012 2nd Ctr 611312012 3rd Qtr 9113/2012 4th Qtr 10/312012 1st Ctr 2113ifoi3 2nd Ctr 6/1812013 3rd atr 9/1212013 4th Qtr 11/1312013 1st Ctr 21512014 2nd atr 5/2312014 3rd Ctr 812712014 4th atr 10/2912014 1st at�2) -31912015 2nd Qtr 3rd Ctr 4th Qtr 1stQtr 2nd Qtr 3rd atr 4th Qtr 1statr 2nd Ctr 3rd Qtr 4thOlr __ .....
6/1112015 8/3112015 1012912015 • 31912016 512312016 7/25/2016 10/1212016
31812017 6/1312017 712612017 10111/2017 OWMRC solit sam le 1stQtr 311212018 2nd Ctr 61812018 3rd Ctr 812212018 4th Qtr 11/2812018 1st Ctr 318/2019 2nd Qtr 61512019 3rd Qtr 91412019 4th Qtr 1211812019 1st Ctr 211912020 2nd Qtr 5111/2020 3rd Ctr 91412020 4th Qtr 1012812020 1st Ctr 2123/2021 2nd Ctr 61912021 3rd Qtr 812412021 4thQtr 121112021 1stOtr 31912022 2nd Qtr 61812022 3rd Qtr 911512022 4thQtr 1113012022 1st Ctr 3n12023
Carbon Tetrachloride Chloroform 170 µg/L) NA 4.400 NA 3,590 4.400 4,400 <50 4,400 <50 4,300 4,080 1.7 3,660 1.3 3.600 1.6 3,800 1.7 4,500 1.6 4.400 340 <1.0 640 <1.0 900 NA #NIA <2.0 1.000 <1.0 1,000 <1.0 980 <1.0 1,000 <1.0 860 820 <1.0 820 <1.0 800 <1.0 720 <1.0 1,000 <1.0 930 820 <1.0 1500 <1.0 610 <1.0 <1.0 740 <1.0 730 3.23 867 <1.0 788 <1.0 865 <1.0 874 5.19 785 <1.0 751 <1.0 719 <1.0 803 1.24 <1.0 2.710 <1.0 1,120 �1.0 2,730 2.660 2.19 3,340 <1.0 3,200 <1.0 3.200 1.71 3,310 1.83 3,370 1.81 3.290 1.48 2,880 <38 2.900 1.82 3,090 1.34 2.800 1.47 3,050 1.33 2.930 1.48 2,820 1.52 2.970 1.47 2.790 <1.0 3.250 <1.0 2,990 1.37 2.810 1.47 3,070 <1.0 2,670 <1.0 -2}50 <1.0 3,320 <1.0 2.600 <1.0 2.850 <1.0 2,780 1.0 2,550 <1.0 3,020 <1.0 2.900 <1.0 2 430 (1) As of March 2012 both north and south WIid lrfe ponds no lonper receMng water (2)Chloroform�yJW!aweMstarted 1114115 -------· NA = not anatyzed Bold and italics indicates the MOL exceeded the GWQS Bold and italics indicates the MOL exceeded the GWQS. J = Approximated value
OUSA White Mesa Mill
Parameter
Chloromethane Methylene Chloride Chloride (30 µg/L) 15 ua/LI No GWQS lma/L)
NA NA NA NA NA NA <10 NA <100 58 <50 56 <50 56 <50 <50 55
2.7 1.3 55 1.6 54 <1.0 53 <1.0 53 <1.0 1.2 53 <1.0 <1.0 63 <1.0 <1.0 46 <1.0 42 NA NA 47 <2.0 <2.0 NA <1.0 <1.0 49 <1.0 <1.0 44 <1.0 <1.0 49 <1.0 <1.0 46 <1.0 <1.0 42 <1.0 <1.0 40 <1.0 <1.0 43 <1.0 <1.0 49 <1.0 <1.0 46 <1.0 <1.0 49 <1.0 48 <1.0 <1.0 46 <1.0 <1.0 43 <T_o------<1.0 ----------------52 <1.0 <1.0 49 <1.0 <1.0 50 <1.0 <1.0 47.3 <1.0 <1.0 49.3 <1.0 <1.0 46.6 <1.0 <1.0 46.7 <1.0 <1.0 48.5 <1.0 <1.0 51.6 1.2 <1.0 48 <1.0 <1.0 --------56.4 <T_o------<1.0-------49.8 <1.0 <1.0 62.2 <1.0 <1.0 73.1 <1.0 <1.0 55.3 <1.0 <1.0 55.5 <1.0 <1.0 56.4 <1.0 <1.0 55.3 <1.0 <1.0 57.2 <1.0 <1.0 49.8 <1.0 <1.0 51.4 <1.0 <1.0 51 <1.0 <1.0 49.7 <60 140 � 52 <1.0 <1.0 54 <1.0 <1.0 52.4 <1.0 <1.0 53.3 <1.0 <1.0 45.4 <1.0 <1.0 46.8 1.4 <1.0 45.3
<1.0 <1.0 48.8 <1.0 <1.0 49.0 <1.0 <1.0 51.9 <1.0 <1.0 48.6 <1.0 <1.0 46.3
3.�-� <1.0 43.3 <1.0 <1.0 49.5 <1.0 <1.0 37.7 <1.0 <1.0 40.2 <1.0 <1.0 48.4 <1.0 <1.0 41.5 2.7 <1.0 44.5 <1.0 <1.0 42.4 <1.0 <1.0 36.6 <1.0 <1.0 39.2
Nitrate, Nitrate + Nitrite I10mg/L) 8.7 10.3 9.4 9.4 9.2
10.0 10.0 10.0 10 1 10.6 10.2 9.8
7.3 7.9 9.5 #NIA 7.3 6.8 7.0 6.6 6.8 6.9 6.7 6.4 6�5 7.3 7.1 7.1
----------ft.8 6.7
3.0 7.0 6.8 7.4 7.8 8.01 8.47 6.92 5.4
----------7�33 8.72 8.48 9.61 7.5 7.13 7.81 8.83 8.92 8.12 7.92 7.78 7.79 8.0 7.89 7.51 7.15 6.85 7.50 8.30 7.15 7.14 7.07 7.56 7.59 7.19 7.21 8.17 5.78 7.44 7.4 5.9 6.90 7.05 5.68
TABLE 1 (15 of 33)
Sampling Event
1st Qtr 3/16/2005 2ndQtr 5/25/2005 3rd Qtr 8/31/2005 4th Qtr 12/7/2005 3/9/2006 2nd Qtr 6/14/2006 3rd Qtr 7/20/2006 thQtr 11/8/2006 2128/2007 6/27/2007 8/15/2007 4th Qtr 10/10/2007 1st Ctr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 10/15/2008 1stOtr 3/11/2009 2nd Qtr 6/2312009 3rd atr 9/14/2009 4th Qtr 12116/2009 2123/2010 2nd Qtr 6/14/2010 3rd Qtr 8/10/2010 Qtr 10/15/2010 Otr 2115/2011 dQtr 5/25/2011 Qtr 8/16/2011 11,1512011
---fl --1/17/2012 -ind Qtr 5/31/2012 3rd Qtr 8/29/2012 4thQtr 10/3/2012 1stQtr 2113/2013 5/29/2013 3rd atr 8/29/2013 4thQtr 11/612013 1/2212014 2nd Qtr 5/21/2014 3rd Qtr 8/2712014 Qtr 10/23/2014 Qtr 3/11/2015 dQtr 6/10/2015 Qtr 9/212015 Qtr 10/21/2015
1stOtr 3/15/2016 2nd Qtr 5/25/2016
Depliea1&TW4.i 3rd Qtr 7/27/2016 4th Qtr 10/1212016 3/14/2017 2nd Qtr 6/14/2017
(5 µg/L)
<1.0
<1.0
<1.0
IGWQSl
170 ua/Ll 130 ua/Ll <1.0
5.8 <1.0 1.0 <1.0 <1.0 1.4 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0
<1.0 <1.0 <1.0 <1.0
<1.0
1.25 3rd Qtr 8/212017 1.2 <1.0
4th Qtr 10/10/2017
11/30/2018 1stOtr 3/16/2019 6/13/2019 3rd Qtr 9/11/2019 4thQtr 12114/2019 1st Qtr 3/17/2020 2ndQtr 6/11/2020 3rd Qtr 9/17/2020 th Qtr 11/4/2020 3/17/2021 l2ndQtr 6/15/2021 atr 9/15/2021 Qtr 12/7/2021 Qtr 3/15/2022 dQtr 6/15/2022 Qtr 9/13/2022 Qtr 12/7/2022
3/2212023
1.19
<1.0
Na GWQS (moll)
19 19 16 16 16 16 18 29 16 16 19
23
23 22 29 35 31 31 32 31 30
34 39 39 36.7 38.6
50.2 50.6 56 60.2 51 51.3 5s:2 66.4 67 67.5 72.6 62.6 67.2 65.3 67 56.2 61.4 59.5 53.6 59.9 56.1 50.8 55.3 52.6 58.0 53.0 51.7 50.3 48.0 52.0 51.8 36.1
53.3 57.9 49.2 50.9 35.9
1.4 1.6 1.5 1.4 1.3 1.4 1.4 1.4 1.5 1.5 1.4 1.4 1.6 2.7 2.7 2.5
3.8 5.1 3.6 4.0 11.0 9.0 8.0 6.5 7.0 6.8 8.0
10.0 13.0 13.0 12.6 14.2 17.4 16.4 18.4 17.0 13.0 16.1 19.2 18.8 16.4 18.0 18.0
30.7 113.0 37.7 25.8 25.9 29.9 25.1 26.7 26.9 26.8 19.8 18.4 13.6 10.4 10.1 8.31
8.04 6.39 4.95 2.34 5.91 3.io 2.39 1.95 1.46
16.0 13.8
7.02
TABLE 1 (16 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-13 Sampling Event
1st Qtr 3/16/2005 2ndQtr 5/25/2005 3rd Qtr 8/31/2005 4th Qtr 1217/2005 1st Qtr 3/9/2006 2ndQtr 6/14/2006 3rd Qtr 7/20/2006
4th Qtr 11/8/2006 1st Qtr 2/28/2007 2ndQtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1st Qtr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 3/4/2009 2nd Qtr 6/23/2009 3rd Qtr 9/14/2009 '\!h_Qtr 12/16/2009 1statr 2/24/2010 2nd Qtr 6/14/2010 3rd Qtr 8/10/2010 4th Qtr 10/15/2010 1stQtr 2/15/2011 2nd Qtr 5/25/2011 3rd Qtr 8/16/2011 4th Qtr 11/15/2011 1st Ofr fl] 111112012
2nd Qtr 5/31/2012 3rd Qtr 8/29/2012 4thQtr 10/3/2012 1stQtr 2/13/2013 2nd Qtr 5/29/2013 3rd Otr 8/29/2013 4thQtr 11/6/2013 istcitr 1/22/2014 2nd Otr 5/21/2014 3rd Qtr 8/23/2014 4thQtr 10/23/2014 1st Qtr 3/11/2015 2ndQtr 6/10/2015 3rd Qtr 9/2/2015 4th Qtr 10/21/2015 1st Qtr 3/16/2016 2ndQtr 5/25/2016 3rd Qtr 7/28/2016 4th Qtr 10/19/2016 1st Qtr 3/16/2017 2nd Qtr 6/15/2017 3rd Qtr 8/2/2017 4th Qtr 10/10/2017 1statr 3/14/2018 2nd Qtr 6/12/2018 3rd Qtr 8/29/2018 4th Qtr 11/30/2018 1stQtr 3/16/2019 2nd Ctr 6/13/2019 3rd Qtr 9/11/2019 4thQtr 12/14/2019 1stQtr 3/17/2020 2ndQtr 6/11/2020 3rd Qtr 9/17/2020 4th Qtr 11/4/2020 1st Qtr 3/17/20:ff 2ndQtr 6/15/2021 3rdQtr 9/15/2021 4th Qtr 1217/2021 1st Qtr 3/16/2022 2nd Ctr 6/15/2022 3rdQtr 9/13/2022 4th Qtr 1217/2022 1st Qtr 3/23/2023
Carbon Tetrachloride (5 uo/LI NA NA <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <·f-b <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 -
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloroform 170 uo/LI <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 �1.0 <1.0 <T_o----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
(1) A:r. of March 2012 both north and southwdd life ponds no longer receM� water
NA= not analyzed Shaded indicates concentrations exceedini:i GWQS
DUSA White Mesa Mill
Parameter IGWQSI Chloromethane Methylene Chloride Chloride
130 ug/LI (5 µa/LI No GWQS (mg/LI
NA NA NA NA NA NA 3.1 <1.0 NA <1.0 <1.0 69 1.7 <1.0 67 1.4 <1.0 66 <1.0 <1.0 65 <1.0 <1.0 33 <1.0 <1.0 59 <1.0 <1.0 59 <1.0 <1.0 58 <1.0 <1.0 58 <1.0 <1.0 54 <1.0 <1.0 58 <1.0 <1.0 50 <1.0 <1.0 58 <1.0 <1.0 58 <1.0 <1.0 57 <1.0 <1.0 63 <1.0 <1.0 60 <1.0 <1.0 53 <1.0 <1.0 53 <1.0 <1.0 55 <1.0 <1.0 55 <1.0 <1.0 60 <1.0 <1.0 56 <1.0 <1.0 60 <1.0 <1.0 54 <1.0 <1.0 55
<T_o------<1.0 ------59 <1.0 <1.0 60 <1.0 <1.0 60 <1.0 <1.0 59.3 <1.0 <1.0 56 <1.0 <1.0 63.5 <1.0 <1.0 58.5 <1.0 <1.0 63.1 <1.0 <1.0 56.1 <1.0 <1.0 62 <1.0 <1.0 66.1 <1.0 <1.0 66.4 <1.0 <1.0 70.3 <1.0 <1.0 76.5 <1.0 <1.0 65.5 <1.0 <1.0 69.4 <1.0 <1.0 71.8 <1.0 <1.0 69.3 <1.0 <1.0 70.9 <1.0 <1.0 66.0 <1.0 <1.0 70.4 <1.0 <1.0 70.5 <1.0 <1.0 60.9 <1.0 <1.0 71.0 <1.0 <1.0 65.0 <1.0 <1.0 73.7 <1.0 <1.0 64.5 <1.0 <1.0 61.6 <1.0 <1.0 65.4 <1.0 <1.0 65.3 <1.0 <1.0 68.7 <1.0 <1.0 63.9 <1.0 <1.0 62.7 <1.0 <1.0 60.2
<1.0 <1.0 60.6 <1.0 <1.0 67.3 <1.0 <1.0 57.7 <1.0 <1.0 54.2 <1.0 <1.0 61.0 <1.0 <1.0 59.2 <1.0 <1.0 62.6 <1.0 <1.0 62.4 <1.0 <1.0 56.9 <1.0 <1.0 57.6
Nitrate, Nitrate + Nitrite (10 mg/LI 4.2 4.3 4.6 4.3 4.2 4.9 4.3 0.8 4.0 4.6 4.4 4.1 3.8 4.2 4.3 4.6 3.7 1.2 4.7 4.1 4.3 5.2 5.6 5.8 5.5 6.4 5.2 5.9
___________ J).5 6.0 6.2 5.9 6.31 6.8 7.16 6.48 7.09 5.99 4.8 6.28 7.09 6.32 5.7 5.78 7.97 5.87 6.14 6.20 605 6.49 6.15 6.17 5.76 6.24 5.13 5.29 5.74 6.56 5.19 5.17 5.5 9.0 5.25 4.92 5.57 2.9 4.80 5.06 4.80 4.5 4.37 4.87 4.47
TW4-14 Sampling Event
1st Qtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4thQtr 1217/2005 ist"dtr 3/9/2006 2nd Qtr 6/14/2006 3rd atr 7/20/2006 4thQtr 11/8/2006 1st0tr 2128/2007 2ndQtr 612712007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1st Qtr 312ai2006 2nd0tr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 3/4/2009 2nd Qtr 6/23/2009 3rd atr 9/14/2009 4th Qtr 12116/2009 istatr 3/23/2010 2nd Qtr 6/14/2010 3rd Qtr 8/10/2010 4th Qtr 10/15/2010 1st Qtr 2115/2011 2ndQtr 6/24/2011 3rd Qtr 8/16/2011 4th Qtr 11/15/2011 i7f'7 ,2012
2nd Qtr 6/14/2012 3rd Qtr 8/29/2012 4th Qtr 10/3/2012 1st Qtr 217/2013 2nd atr 5/29/2013 3rd Qtr 8/29/2013 4th Qtr 11/6/2013 1st Qtr 1/2212014 2ndQtr 5/21/2014 3rd Qtr 8/13/2014 4th Qtr 10/23/2014 1statr 3/1212015 2nd Qtr 6/10/2015 3rd Qtr 9/3/2015 4th Qtr 10/23/2015 1stQtr 3/16/2016 2nd Qtr 5/26/2016 3rd atr 8/3/2016 4th Qtr 10/20/2016 1stQtr 3/15/2017 2nd atr 6/15/2017 3rd Qtr 8/212017 4th Qtr 10/10/2017 1stQtr 3/15/2018 2nd Qtr 6/13/2018 3rd Qtr 8/30/2018 4thQtr 1211212018 1stQtr 3/16/2019 2nd Qtr 6/13/2019 3rd Qtr 9/11/2019 4th Qtr 12114/2019 1st0tr 3/17/2020 2nd Qtr 6/11/2020 3rd Qtr 9/18/2020 4th Qtr 11/4/2020 1stQtr 3/18/2021 2nd Qtr 6/16/2021 3rdQtr 9/15/2021 4th Qtr 1218/2021 1stQtr 3/16/2022 2nd Ctr 6/16/2022 3rdQtr 9/14/2022 4th Qtr 1218/2022 1st Qtr 3/23/2023
TABLE 1 (17 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
Carbon Tetrachloride (5 µa/L) NS NS NS NS NS NS NS <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
DUSA White Mesa Mill
Parameter IGWQSI Chloromethane (70 ua/LI (30 ug/L) · rs µg/LI NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS NS <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T.O ____ <T.O ______ <1.0 ------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.7 <1.0 <1.0 1.82 <1.0 <1.0 <1.0 <1.0 <1.0 1.46 <1.0 <1.0 4.49 <1.0 2.18 6.15 <1.0 3.18 5 <1.0 1.8 7.02 <1.0 1.59 6.45 <1.0 2.18 6.85 <1.0 <1.0 6.14 <1.0 <1.0 6.13 <1.0 <1.0 5.8 <1.0 2.18 5.12 <1.0 <1.0 4.76 <1.0 <1.0 4.41 <1.0 <1.0 4.08 <1.0 <1.0 4.18 <1.0 <1.0 6.08 <1.0 <1.0 3.83 <1.0 <1.0 2.98 <1.0 <1.0 2.87 <1.0 <1.0 2.41 <1.0 <1.0 2.69 <1.0 <1.0 1.77 <1.0 ·<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.0 <1.0 <1.0 1.1 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS (mg/L) NS NS NS NS NS NS NS 37 38 38 36 38 57 35 34 40 35 36 38 34 33 49 35 29 25 24 33 15 20
35 37 37 35.2 38.6 37.6 36.5 35.5 32.5 38 38.9 40'.f 41.8 42.4 40.6 42.4 43.6 42.4 45.6 45.4 46.9 46.4 42.5 51.5 46.9 54.1 48.7 48.7 48.3 45.4 49.4 48.4 47.6 45.1 49.7 48.2 49.5 34.1 49.0 42.0 48.4 42.2 43.5 47.6
(1) As of March 2012 both north and south wild hfe ponds no lon�r rece1v1� water
NS = not sampled Shaded indicates concentrations e)(ceeding GWQS.
Nitrate, Nitrate + Nitrite
110 mg/Ll NS NS NS NS NS NS NS 2.4 -2j 1.4 1.1 0.8 0.4 1.6 1.38 0.7§ 1.6 1.4 1.5 1.4 2.5 2.9 2.8 2.9
1.4 2.6 1.7
3.3 3.9 3.9 4.6 4.4 4.51 4.81 5.92 4.87 4.1 5.22 5.22 3.55 2.77 2.45 2.94 2.45 2.88 2.86 4.36 5.12 4.84 4.73 5.67 6.36 5.34 5.85 6.16 5.86 4.77 4.76 6.17 6.57 5.57 5.81 5.56 7.02 5.56 5.70 5.9 5.30 4.78 6.20 5.58
TW4-16 Sampling Event
TABLE 1 (18 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill
Parameter IGWQSl Carbon Tetrachloride Chloromethane Methylene Chloride Chloride Nitrate, Nitrate + Nitrite
1stQtr 2nd Qtr 3rd Qtr 4th Qtr 1statr 2nd Qtr 3rd Qtr 4th Qtr 1st Ctr 2nd atr 3rd Qtr 4thQtr 1st Qtr 2nd Qtr 3rd Qtr 4th Qtr 1st Ctr 2nd Qtr 3rd Qtr 4thQtr 1stQtr 2nd Qtr 3rd Qtr 4thQtr
3/16/2005 5/25/2005 8/31/2005 1217/2005 3/9/2006 6/14/2006 7/20/2006 11/8/2006 2/28/2007 612712007 8/15/2007 10/10/2007 3/28/2008 6/25/2008 9/10/2008 10/15/2008 3/4/2009 6/23/2009 9/14/2009 12/17/2009 3/24/2010 6/14/2010 8/24/2010 10/15/2010
5/26/2011 8/17/2011 11/16/2011 1) 1217/2011
15 uo/L) NA NA <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.o <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1 0 <1 0 <1 0 NA <1 0 <1 0
170 uo/LI (30 uo/LI 240 212 NA 85 3.2 14 2.6 39 1.1 13 2.4 5.2 <1.0 13.6 <1.0 8.7 <1.0 2.6 <1.0 7.1 <1.0 1.4 <1.0 11 <1.0 <1.0 <1.0 10 <1.0 3.9 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 2.1 <1.0 4.3 <1.0 3 <1.0 15 <1 0 16 <1 0 9 2 <1 0 NA NA <1 0 <1.0 <1 0 <1.0 3) --1/18/2012 5/26/2012 <1 0 ----<TO ____ <1.0 ______ 8/30/2012 4th Qtr 10/3/2012 1stQtr 217/2013 2nd Qtr 5/30/2013 3rd Qtr 9/5/2013 1117/2013 air 1/29/2014 Qtr 5/22/2014 Qtrl2l 8/14/2014 Qtr 9/24/2014 4th Qtr 10/29/2014 1stQtr 3/12/2015 2nd Ctr 6/11/2015 3rd Qtr 9/3/2015 4th Qtr 10/28/2015 1stQtr 3/17/2016 2nd Qtr 5/26/2016 3rd Qtr 8/3/2016 4th Qtr 10/26/2016 1st Ctr 3/16/2017 2nd Q1r 6/20/2017 3rd Qtr 8/3/2017 4th Qtr 10/11/2017 DWMRC SDlit samole 1stQtr 3/20/2018 Duplicate TW4-75 2nd Qtr 6/14/2018 3rd Qtr 8/30/2018 4th Qtr 12/12/2018 1stQtr 3/19/2019 2nd Qtr 6/19/2019 3rd Qtr 9/12/2019 4th Qtr 12/14/2019 n,.�ll..�te TW4-75 1stQtr 3/18/2020 2nd Qtr 6/12/2020 rd Qtr 9/1912020 l4thQtr 11/11/2020 !Duplicate TW4-75
�
s,lrtsam,le 3/24/2021 r 6/17/2021 9/23/2021 14th Qtr 12/8/2021 1st Qtr 3/23/2022 12nd Qtr 6/22/2022 13rd Qtr 9/15/2022 �t_t}.Ql!__ ___ 12/9/2022 1stQtr 3/29/2023 Duolicate TW4-75
<1 0 <1 0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.95 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <10 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 {1) voes were re sampled because laboratory missed holding time (2) voes were resampled
<1.0 <1.0 <1.0 <1.0 <1.0 13.4 <1.0 6.93 <1.0 14.6 <1.0 229 <1.0 371 <1.0 387 <1.0 153 <1.0 65.3 <1.0 82 <1.0 112 <1.0 45.9 <1.0 93.4 <1.0 49 <1.0 92.9 <1.0 19.1 <1.0 64.3 <1.0 143 <1.0 98 <1.0 92 <1.5 170 <1.0 171 <1.0 54.5 <1.0 54.5 <1.0 52.0 <1.0 60.6 <1.0 76.2 <1.0 99.8 <1.0 94.3 <1.0 91.0 <1.0 113 <1.0 141 <1.0 220 <1.0 270 <1.0 277 <1.0 290 <20 248 <1.0 247 <1.0 202 <1.0 189 <1.0 150 <1.0 120 <1.0 138 <1.0 152 <1.0 179 <1.0 178 <1.0
(3) As of March 2012 both north and south wfld lite ponds no k)nger receiving water. NA=n.otanatvz:ed --------------------
Shaded indicates concentrations exceedinR GWQS. J = Approximate value H = Sample was analyzed beyond holdini:i times and may not be accureate concentration
(5 µg/L) No GWQS (mg/LI 110 mg/LI NA NA <0.1 NA NA <0.1 43 NA <0.1 5.9 21 8.9 2.7 9.2 6.6 1.8 5.1 1 26 <1.0 14 6.6 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA 1.4 1.i <1.0 ------
<1.0 <1.0 <1.0 4.21 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.9 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
64 1.4 60 3 55 1.9 60 2.7 62 .. h6 79' 12.3 75 9.9 65 5.4 69 4.4 52 <0.1 58 1.5 71 10.5 89 9.8 73 9.6 76 8.9 79 8.8 76 5.2 77 4.2 64 4.7 72 4.6 71 3.3 86 7 81 5 63 1.7 38 0.4 NA ,,__ 48 ---------53 <0.1 59 <0.1 59 <0.1 58.1 <0.1 49.8 <0.1 54.4 <0.1 56.6 1.37 66.8 3.16 80.7 4.94 80 5.1 NA NA 92.1 8.4 65 4.3 61 1.06 65.8 1.18 58.3 1.69 1.63 61.3 1.89 60 2.20 66.7 2.78 62.2 2.75 60.6 1.81 67.1 2.63 54.2 2.12 64 2.00 85.1 4.55 84.7 4.51 62.5 2.83 73 2.53 68.8 2.88 66.3 3.36 71.5 2.43 72.9 3.55 88.6 3.37 84.1 3.12 76.2 3.91 79.7 4.44 77.4 4.74 85.9 5.73 85.6 5.74 87.0 0.37 H 92.6 5.82 87.4 6.74 77.4 4.74 89.9 4.85 84.3 5.0 93.2 4.2 89.8 4.41 91.0 4.75 88.5 5.69 92.5 5.09
TW4-18 Sampling Event
TABLE 1 (19 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill
Parameter IGWQSI Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride (5 µg/L) 170 ua/Ll 130 µg/Ll (5 µg/L) No GWQS (mg/L) 1st Qtr 3/16/2005 NA 38 NA NA NA 2ndQlr 5/25/2005 NA 29.8 NA NA NA 3rd Qtr 8/31/2005 <1.0 39 2.8 <1.0 NA 4th Qtr 12/7/2005 <1.0 14 1.1 <1.0 41 1stQtr 3/9/2006 <1.0 12 1.6 <1.0 36 2nd Qtr 6/14/2006 <1.0 12 2.7 <1.0 35 3rd Qtr 7/20/2006 <1.0 10.8 <1.0 <1.0 35 4thQtr 11/8/2006 <1.0 12.5 <1.0 <1.0 34 1stQtr 2/28/2007 <1.0 S:2 <1.0 <1.0 30 2nd Qtr 6/27/2007 <1.0 8 <1.0 <1.0 28 3rd atr 8/15/2007 <1.0 8.9 <1.0 <1.0 32 4th Qtr 10/10/2007 <1.0 7.4 <1.0 <1.0 27 1statr 3/28/2008 <1.0 6.4 <1.0 <1.0 23 2nd Qtr 6/25/2008 <1.0 5.7 <1.0 <1.0 23 3rd Qtr 9/10/2008 <1.0 a <1.o <1.0 26 4th atr 10/15/2008 <1.0 9.4 <1.0 <1.0 30 1stQtr 3/4/2009 <1.0 11 <1.0 <1.0 29 2nd Qtr 6/23/2009 <1.0 16 <1.0 <1.0 30 3rd Qtr 9/14/2009 <1.0 13 <1.0 <1.0 26 4th Qtr 12/17/2009 <1.0 8.2 <1.0 <1.0 30 1stQtr 3/24/2010 <1.0 69 <1.0 <1.0 41 2nd Qtr 6/14/2010 <1.0 29 <1.0 <1.0 35 3rd Qtr 8/12/2010 <1.0 29 <1.0 <1.0 37 4th Qtr 10/15/2010 <1.0 30 <1.0 <1.0 50 1st Qtr 2/22/2011 <1.0 39 <1.0 <1.0 52 2ndatr 5/26/2011 <1.0 26 <1.0 <1.0 36 3rd Qtr 8/17/2011 <1.0 29 <1.0 <1.0 23 4th Qtr 11/16/2011 NA NA NA NA 23 1s1oorR---�¾MI§H <1.0 28 <1.0 <1.0 NA ·:c·1.o 25 <1.0 <1.0 18 2nd Qtr -6/13/2012 <1.0 --------24 <T.O ______ <1.0 ---------------30 3rd Qtr 9/11/2012 <1.0 38 <1.0 4th Qtr 10/3/2012 <1.0 30 <1.0 1st Qtr 2/13/2013 <1.0 34.9 <1.0 2ndQtr 6/13/2013 <1.0 37.9 <1.0 3rd Qtr 9/5/2013 <1.0 41 <1.0 4th Qtr 11/13/2013 <1.0 44.3 <1.0 1s1oir 1/30/2014 <1.0 6.93 <1.0 2ndQtr 5/22/2014 <1.0 6.93 <1.0 3rd Qtr 8/14/2014 <1.0 32.8 <1.0 4thQtr 10/28/2014 <1.0 33 <1.0 1st Qtr 3/12/2015 <1.0 32 <1.0 2nd Qtr 6/11/2015 <1.0 30.5 <1.0 3rd Qtr 9/3/2015 <1.0 28.7 <1.0 �_Qtr ___ -··· 10/28/2015 <1.0 52.9 <1.0 1st Qtr 3/17/2016 <1.0 ss:s <1.0 2nd Qtr 6/8/2016 <1.0 60 <1.0 3rd atr 8/3/2016 <1.0 56.3 <1.0 4th Qtr 10/26/2016 <1.0 60.1 <1.0 1st Ctr 3/16/2017 <1.0 62 <1.0 Duplicate TW4-75 <1.0 61.5 <1.0 2nd Qtr 6/20/2017 <1.0 63.8 <1.0 3rd Qtr 8/3/2017 <1.0 62.8 <1.0 Duplicate TW4-75 <1.0 62.3 <1.0 4th Qtr 10/11/2017 <1.0 62.9 <1.0 1stQtr 3/15/2018 <1.0 62.3 <1.0 2nd Qtr 6/13/2018 <1.0 59.9 <1.0 3rd Qtr 8/30/2018 <1.0 56.2 <1.0 4th Qtr 12/13/2018 <1.0 57.6 <1.0 1stQtr 3/19/2019 <1.0 52.8 <1.0 2nd Qtr 6/19/2019 <1.0 54.2 <1.0 Duplicate TW4-75 <1.0 54.4 <1.0 3rd Qtr 9/11/2019 <1.0 56.2 <1.0 4th Qtr 12/18/2019 <1.0 62.0 <1.0 1stQtr 3/18/2020 <1.0 57.0 <1.0 2nd Qtr 6/12/2020 <1.0 58.2 <1.0 3rd Qtr 9/18/2020 <1.0 60.0 <1.0 4th Qtr 11/11/2020 <1.0 58.6 <1.0 DWMRC solit sam le <10 56.0 <20 -----·-1stQtr 3/18/2021 <1.0 52.0 <1.0 2nd Qtr 6/16/2021 <1.0 58.2 <1.0
�;� Qtr 9/22/2021 <1.0 49.9 <1.0 Qtr 12/8/2021 <1.0 57.0 <1.0 1stQtr 3/23/2022 <1.0 56.0 <1.0 l2ndQtr 6/22/2022 <1.0 62.9 <1.0 13rd Qtr 9/14/2022 <1.0 60.6 <1.0 llthQtr 12/9/2022 <1.0 62.6 <1.0 TW4-75 <1.0 67.9 <1.0 3 <1.0 54.4 <1.0 111 laboratory i:nis�ed holding time. (2) As of March 2012 both north and south wlld hfe ponds no longer receiving water. NA = not analyzed Shaded indicates coocentrations exceedini:i GWQS
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
_'.:).O <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
.... •••••···•··········
26 27 23.1 22.9 36.2 37.1 38.9 47 49 40.8 41.6 43.5 47.6 39.4 40.7 43.8 40.7 43.9 39.4 41.1 41.6 40.4 41.5 37.1 44.3 39.5 45.6 38.2 37.6 39.5 40.8 36.8 42.7 39.4 41.4 38.7 39.6 41.0 41.8 41.4 29.8 41.1 39.1 48.1 44.7 44.4 45.2 45.6
Nitrate, Nitrate + Nitrite (10mg/L) 14.1 12.9 13.3 7.3 5.9 4.7 6.1 5.7 5.1 4.9 5.0 4.4 0.7 4.6 4.9 5.2 5.2 6.2 5.9 5.4 5.1 9.0 9.0 10.0 . ·1oo9.0 4.6 6.3 NA
' ----------· j.� 6.6 6.6 6.0 5.6 8.9 12.1 14.2 ............. 12.ll
12.2 9.8 ,,., 11.7 9.69 15.7 6.24 5.96 5.45 5.79 5.24 4.47 4.41 4.50 4.24 4.31 4.43 4.32 4.09 3.51 3.60 3.85 4.01 2.95 3.25 3.02 3.71 3.62 3.36 3.67 3.30 3.61 3.62 3.37 3.90 3.4 3.4 3.46 3.60 3.63 3.4
TW4-19 (chlorotrom pumping weU started4/30/03) Sampling Event
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4th Qtr 12/7/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd Qtr 7/20/2006 4th Qtr 11/8/2006 1statr 2/28/2007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1statr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 1stQtr 3/4/2009 2nd Qtr 6/23/2009
TABLE 1 (20 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
OUSA White Mesa Mill
Parameter (GWQS)
Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride
(5 ua/L) 170 ua/LI 130 ug/LI -15 ug/LI No GWQS lmg/LI NA 2,200 NA NA NA
NA 1.200 NA NA NA
<5.0 1.400 <5.0 <5.0 NA <50 2,800 <50 <50 81 <50 1,200 <50 <50 86
<50 1,100 <50 <50 116
<50 1,120 <50 <50 123 1.6 1.050 2.6 <1.0 134 1.3,�0<1.0 <1.0 133 Did not sample 1.9 1.100 <1.0 <1.0 129 1.9 1.100 <1.0 <1.0 132 2.9 1.860 <1.0 <1.0 131 <1.0 1,000 <1.0 <1.0 128 8.6 3,600 <1.0 <1.0 113 12 4.200 <1.0 <1.0 124 1.2 1.100 <1.0 <1.0 127 1.2 990 <1.0 <1.0 132
Nitrate, Nitrate + Nitrite I10ma/L) 5.3 5.7 4.6 <0.1 4 5.2 4.3 4.6 4
4.1 4 2.2 2.8 35.2 47.8 3.2 2.4
3rd Qtr 9/14/2009 15 6,600 <1.0 <1.0 43 <0.1
4th Qtr 12/22/2009 1st Qtr 2/17/2010 2ndQtr 6/14/2010 3rd Qtr 8/16/2010 4th Qtr 10/15/2010 1st Qtr 2/17/2011 2ndQtr 6m2011 3rd Qtr 8/17/2011 4th Qtr 11/16/2011 (1) 12/5/2011 1stOir/2L _ _ 112312012
2ndOtr 6/6/2012 3rd Qtr 9/4/2012 4th Qtr 10/3/2012 1st Qtr 2/13/2013 2ndQtr 6/5/2013 3rd Otr 9/3/2013 4th Qtr 10/29/2013 151-0tr 1/27/2014 2nd Qtr 5/19/2014 3rd Qtr 8/11/2014 4th Qtr 10/21/2014 1st Qtr 3/9/2015 2nd Qtr 6/8/2015 3rd Qtr 8/31/2015 4th Qtr 10/19/2015 1st Qtr 3/9/2016 2nd Qtr 5/26/2016 3rd Qtr 7/25/2016 4th Qtr 10/13/2016 1stQtr 3iai2017 2nd Qtr 6/13/2017 3rd Qtr 7/26/2017 4th Qtr 10/11/2017 1st Qtr 3/12/2018 2nd Qtr 6/8/2018 3rd Qtr 8/30/2018 4th Qtr 11/28/2018 1st Qtr 3/8/2019 2nd Qtr 6/5/2019 3rd Qtr 9/4/2019 4th Qtr 12/10/29JJl 1stQtr 2/19/2020 2nd Qtr 5/27/2020 3rd Qtr 9/4/2020 4th Qtr 10/28/2020 1stQtr 2/23/2021 2nd Qtr 6/9/2021 3rd Qtr 8/24/2021 4th Qtr 12/1/2021 1st Qtr 3/9/2022 2nd Qtr 6/8/2022 3rd Qtr 8/30/2022 4th Qtr 11/30/2022 1stQtr 3f7/2023
<1.0 -------
<1.0
�tQ
<1.0
<1.0
<1.0
16 4,700 1.3 940 4.2 1.800 4.9 2.000 1.3 1.200 17 3,400 8.3 4,000 2.1 970
5.4 2,200 1.5 ·s5O 1.1 ----460 3.5 950 4 1500 5.15 4,210 5.15 2,070 20.7 8,100 6.42 942 4.05 586 5.51 810 1.9 1.410 .H , .•...••........ 4,310 8.92 4,660 2.62 1,570 7,860 12.2 7,840 .. 13.5 7,780 23.1 12,600 9.89 6,040 10.8 6,640 3.06 1,240 1.35 510 13.0 8,840 129 1.36 2,640 3.45 2,980 2.03 1,910 6.18 5.270 2.43 2,050 15.9 11,500 10.1 6,670 551 13.7 8,720 10.4 7,600 1.98 1,350 1.1 660 8.4 6,660 775 7.83 4.450 13.2 6,950 654 2.7 2,540 2.5 4,750 8.0 7,380 230
(1) VOCs were resampled because laboratory missed holdmg lime.
<1.0 <1.0 <1.0 <f.'6 <1.0 <1,0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 ______ <1.0 -----
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 8.3 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 7.78 <1.0 5.46 <1.0 . ..1.4 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 5.41 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 5.41 <1.0 <1.0 <1.0 1.98 1.25 <1.0 <1.0 <1.0 <1.0 4 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
(2) As of March 2012 both north and south wild life ponds no longer receiving water. _____ _ NA = not analyzed Bold and italics indicates the MOL exceeded the GWQS Shaded indicates concentrations e11:ceedinA GWQS
124 26.7 144 2 132 4.4 142 5.9 146 2.7 135 17.0 148 12.0 148 3.0 148 5.0
138 ----------!).6 --149 2.4 149 2.5 150 4.1 164 8.0 148 3.0 179 17.6 134 4.7 134 1.6 152 1.3 140 1.6 130 4.7 238 8.56 180 0.916 326 11.6 252 10.6 ----276 15.70 204 1.27 214 10.5 200 10.0 461 11.1 135 0.243 218 1.120 139 0.377 193 8.6 138 0.494 166 2.55 140 0.233 197 6.58 160 8.96 153 0.33 147 0.5_li 205 10.1 147 1.14 188 11.6 104 1.1 167 6.6 115 4.04 172 6.68 184 11.0 119 1.7 128 1.4 178 4.76 129 3.6 -··-·--122 1.75
TW4-20 (chloroform pumping well started 8/4/05)
TABLE 1 (21 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
OUSA White Mesa Mill
Parameter
(GWQS)
Sampling Event Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride (5 ua/L) Chloride Nitrate, Nitrate +Nitrite 110 mg/LI 15 ua/L) 170 ua/LI 130 ua/L) No GWQS (ma/L) 1st Otr 3/16/2005 2nd Qtr (3) 5/25/2005 NA Monitor well was not installed NA
Jn:t at,----513112005 <10 ---------39,000 NA
3,800 <10 19,000 <250 9,200 <500 61,000 <500
<10 --------NA _______ __________ 10}0 � 2� 4th Qtr 12/7/2005 <250 1st Otr 3/9/2006 <500 2nd Qtr 6/14/2006 <500 3rd Qtr 7/20/2006 <1000 4th Qtr 11/8/2006 1st Qtr 2/28/2007 2nd Qtr 6/27/2007
3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1st Otr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qlr 10/15/2008 NA 1st Qtr 3/4/2009 2nd Qtr 6/23/2009
3rd Qtr 9/14/2009 4th Qtr 12/22/2009 1st Qtr 2/17/2010 2nd Qtr 6/14/2010
3rd Qtr 8/16/2010 4th Qtr 10/15/2010 1st Otr 2/17/2011 2nd Qtr 617/2011 3n:t Otr 8/17/2011 4th Qtr 11/16/2011
5,300 <1000
<250 131 1.80
<500 120 3.80 <500 235 9.40 <1000 134 2.90 1, , ,.ooo,____ ____ ,�.9"-'------�2-�2,____ _____ ,�2�4-1-______ _,3".5""0
3.1 4.400 <1.0 ,_, 124 4.20 2.2 1,800 <1.0 <1.0 112 2.30 3.5 5.200 <1.0 1.8 117 2.10 6.8 9,000 <1.0 1.9 170 5.60 9 13,000 <1.0 1.5 132 0.90 13 30.000 <1.0 1.2 191 8.00 15 21,000 <1.0 3.7 156 4.44 NA � NA 168 5.51 5.7 8.200 <1.0 5.2 164 5."fo 4.9 6.800 <1.0 4.2 164 2.90 a.4 13.ooo <1.o � 4.4 153 3.30 14 15,000 <1.0 3.0 187 5.30 2.7 3.500 <1.0 3.2 179 2.00 ,, 18.000 <1.0 3.7 200 5.60 12 15,000 <1.0 ,_ 2.2 196 5.30 20 24.ooo.,<_1�.o� _____, 5.5 203 4.60 27 31,000 <1.0 ,-19.0 220 4.40 10 8.100 <1.0 2.1 177 4.80 7.3 3.800 <1.0 3.1 207 6.50 7.2 7.900 <1.0 2.5 186 4.20 10 11,000 <1.0 1.3 207 7.90 1ist atr{2L __ 112312012 2nd Qtr 6/6/2012 ----------33 ---36.000 <1.0 <1.0 ________ --------262 ---------1U)O 3rd atr 9/4/2012 4th Qtr 10/3/2012 1st Qtr 2/11/2013 2nd Qtr 6/5/2013
3rd Qtr 9/3/2013 4th Qtr 10/29./20.J] _ 1st Qtr 1/27/2014 2nd Qtr 5/19/2014 3rd atr 8/11/2014 4th Qtr 10/21/2014 1st Otr 3/9/2015 2nd Qtr 6/8/2015
3rd Qtr 8/31/2015 4th Otr 10/19/2015 ___ ....... 1st Qtr 3/9/2016 2nd Qtr 5/23/2016 3rd Qtr 7/25/2016 4th Qtr 10/12/2016 1st Qtr 3/8/2017 2nd atr 6/13/2017
3rd Qtr 7/26/2017 4th Qtr 10/12/2017 1st Qtr 3/1212018.
2nd Qtr 6/14/2018 <1.0
26 13.000 <1.0 <1.0 289 10.80 22 19.000 <1.0 <1.0 302 11.00 19.6 18.500 <1.0 1.21 252 9.07
32.5 26,300 <1.0 1.3 250 9.80 25.7 26,800 <1.0 2.14 260 8.65 17.3 15.700 <1.0 1.37 272 9.64 18.4 17,800 <1.0 2.04 254 7.56 22 1 22.100 2.31 3.98 269 5.95 14 1 12.400 55.2 2.2 299 4.30 18.5 23.300 4.04 2.38 292 7.67 20.8 19,900 4.85 1.38 290 9.80 16.2 17,600 13.4 1.73 296 5.76 15.1 17.000 12.3 <1.0 365 9.3 14.5 _____ ,c,7_.,.00=01------"10"".8"!--------'-11--____ _,2,.,9,,,3-1------______ ,-,,6,,.2"!3 20.2 21,600 4.09 1.16 293 10.30 40.6 33.700 <1.0 <1.0 318 11.2 26.6 23.600 <1.0 <1.0 307 11.3 �;: �j:!��,_:�:�:��------+-:�:�:�---------1-------���=6 )H 23.4 18.100 <1.0 <1.0 281 9.76 25.0 27.600 1.25 <1.0 292 10.8 11.2 11.600 2.34 <1.0 293 8.91 15.9 15.400 1.77 2.36 289 9.5 12.000 <1.0 7.77 258 10.40
3rd Qtr 8/22/2018 9.85 10,500 4.98 <1.0 282 8.14 ��� g:; ____ 11��::��)•-c�+-------'�'cS3�.�•l
2nd Qtr 6/5/2019 10.1
3rd Qtr 9/4/2019 8.39 4th Qtr 12/10/2019 5.92 1st Qtr 2/19/2020 8.6 2nd atr 5/27/2020 6.74
(1) VOCs were resampled because laboratory mrssed holding bme.
9,500 15.6 <1.0 295 9.72 15.600 <1.0 <1.0 272 6.7 13,700 <1.0 <1.0 279 9.59 10.500 <1.0 <1.0 286 10.20 8,790 2.67 <1.0 307 9.75 14,300 10.7 <1.0 310 9.81 5,800 1.3 12.3 3.01 7.23 Well TW4-20 Abandoned in October 2020
(2) As of March 2012 both nortfl and sooth wHd life ponds no longer receiving water.
j3) Chloroform pum.e,1n.,2 wea started 6/4105
NA = not analyzed
Bold and rtalics indicates the MDL exceeded the GWQS. Shaded indicates concentrations exceedinQ GWQS.
TABLE 1 (22 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Qu arter 2023 Chloroform C ontamination Investigation OUS A White Mesa Mill
-21 Parameter (GWQS) (cNoro;�n;:;i�ui�;:�:'9'15'f---=ca-rb�on�Te�t-ra-c7hl�o�ri�de��C7h�lo -,o�fo-rm -�C�h7lo-,o-m-e�t�ha_n_e��M�et�h-y-le-ne�C-hl-o�rid-•�-�C�h-lo-n-·d�•--�N-i -tr -at-•-. N_rt_ra_t_e _+_N-it_ri_te--11 (5 ug/L) 170 uo/LI 130 un/LI 15 µg/Ll No GWQS Ima/LI (10 mg/L) 1stQtr
2nd Qtr 3rd Qtr 4thQtr
1stQtr 2nd Qtr 3rd Qtr 4th Qtr
1stQtr
2nd Qtr 3rd Qtr 4thQtr 1st Ctr
2nd Qtr 3rd Qtr 4thQtr
3/16/2005 5/25/2005 NA 8/31/2005 <5.0
12/7/2005 <1.0 31912006 <2.5 611412006 <2.5 712012006 <2.5 11/8/2006 2/2812007 612712007 8/1512007 <1.0 1011012007 <1.0 3/28/2008 6/2512008 9/1012008 1011512008 NA
11/18/2008
1stQtr 3/11/2009 <1.0 j Qtr 6/2312009 <1.0 Qtr 911412009 <1.0
1.8 5.8
7 1.7 1.6 #NIA 2
�g=:;--�1=�=2=i=�g��=�+:�:=.g�-----+······ j Qtr 611412010 <1.0 Qtr 811312010 9.2 �
1
tsht_0q�ttrr __ �10',;1cc'15',;12�occ1-'cot------�1'c'.2+··· 2/22/2011 1.2 ?nd Qtr 612812011 4.8 1Jrd Qtr 811712011 6.3 4th Qtr 11/16/2011 ill 12/712011 wa1r·121 -112312012
2nd Qtr --61612012 13rd Qtr 91412012 '4th Qtr 1013/2012 1stQtr 2/1112013 12nd Qtr 61512013 3rd Qtr 91312013 Mh Qtr 10/2912013 <1.0 1st Qtr 1/27/2014
2nd atr 511912014 3rdQtr 811112014 <1.0
6.7 6.4 5.4 6 7 �5 3.49 2.13
6.23 4.73
4th Qtr 1012112014 1.04
1stQtr 31912015 1.75 2nd Qtr (3) 61812015 1.92
�
atr ____ 813112015 <1.0 ---------atr 1011912015f.:<"-1"'.o ______ , Qtr 31912016 <1.0 Qtr 512312016 <1.0 Qtr 712512016 <1.0 4th Qtr 10112/2016 <1.0
1st Qtr 31812017 2nd Otr 611312017 3rd Qtr 712612017 4thOtr 1011112017 <1.0
OWMRC sclit samole <3.8
1st Qtr 3112/2018
2nd Qtr 6/812018 <1.0 3rd Qtr 8122/2018 <1.0 4th Otr 10122/2018 <1.0
1st Qtr 31812019 <1.0
2nd Otr 61512019 <1.0 3rd Qtr 91412019 <1.0 4th Qtr 12/1012019 <1.0
1st Otr 2/1912020 <1.0 2nd Qtr 512712020 <1.0 3rd Otr 914/2020 <1.0
2.36
1.16 1.05
2.36
z11g:; 1���gi� ;h,e.O _____ __,_
2nd Qtr 619/2021 <1.0 3rd Qtr 812412021 <1.0 4th Qtr 12/112021 <1.0 1st Otr 31912022 <1.0
2nd Otr 6/812022 <1.0 3rd Qtr 8/3012022 <1.0 4th Qtr 11/30/2022 <1.0
1st atr 3nt2023 <1.0
Monitor well was not installed 192 NA NA NA 14.6 78 <5.0 <5.0 NA 10.1
1��t-:'c1�.�'----+:-=-1'=�------+------';"'}}+--------"-:"'.�tl
120 <2.5 <2.5 318 10.2
108 <2.5 <2.5 357 8.9 :�� -Hi�---+::.,:�.gc_ ____ -+-----�;&,�64---------"��.�I 300 <1.0 <1.0 327 8.6 140 <1.0 <1.0 300 8.6
120 <1.0 <1.0 288 8.3 390 <1.0 <1.0 331 14. 180 <1.0 <1.0 271 8.1 120 <1.0 <1.0 244 7.57 � � ™ u 170 <2.0 <2.0 NA #NIA
180 <1.0 <1.0 279 8.3 200 <1.0 <1.0 291 8.1
200 <1.0 <1.0 281 9.,
160 <1.0 <1.0 256 8. 170 <1.0 <1.0 ... 228 ......... 8.4 210 <1.0 <1.0 266 12.0 390 <1.0 <1.0 278 14.0 ��g :; g ----t:�;'-'-.g'c------1-----· ;��1---------�'-'-.�"11
290 <1.0 <1.0 290 12.( 460 <1.0 <1.0 287 14.C
287 13.0 ��g11
1!-'.�g----+:::,;�g�-----l-----�2�28cJ-.-------�,,s�.01 400 <1.0 <1.0 ________ --------285 11. 410 <1.0 <1.0 142 13 390 <1.0 <1.0 270 14. 282 <1.0 <1.0 221 11. 328 <1.0 <1.0 243 13. 244 <1.0 <1.0 207 10.3
204 <1.0 <1.0 206 9.0
220 <1.0 2.04 200 11.4
240 <1.0 2.04 243 11.5
204 <1.0 <1.0 230 7.1 229 <1.0 <1.0 252 10.0
292 <1.0 <1.0 255 10.9 366 <1.0 <1.0 494 13.1 281 <1.0 -<1.0 --------------499 14.7 339 <1.0 <1.0 +------�·1�3c,............... ... 14.3 390 <1.0 <1.0 452 14.6 545 <1.0 <1.0 425 13.1 456 <1.0 <1.0 457 16.5 456 <1.0 <1.0 439 13.5 598 <1.0 <1.0 452 17.7
224 <1.0 <1.0 309 9.53 537 <1.0 <1.0 447 18.20 466 <1.0 <1.0 378 16.90 400 <6.0 14 J 310 11 421 <1.0 <1.0 447 15.8 532 <1.0 <1.0 387 14.1 476 <1.0 <1.0 182 0.236 585 <1.0 <1.0 392 15.2 323 <1.0 <1.0 180 8.99 734 <1.0 <1.0 456 17.5 596 <1.0 <1.0 478 14.7 794 <1.0 <1.0 339 5.73 844 2.58 <1.0 441i' 8.93 767 <1.0 <1.0 353 15.4 920 <1.0 <1.0 382 12.6 948 <1.0 <1.0 411 16.3 400 <1.0 <1.0 454 15.20
1.130 <1.0 <1.0 461 21.5 669 <1.0 <1.0 375 12.9 649 <1.0 <1.0 227 17.2 469 <1.0 <1.0 1 io 2.2 657 <1.0 <1.0 331 8.9 1,070 <1.0 <1.0 425 14.3 482 <1.0 <1.0 158 2.12 469 <1.0 <1.0 335 10.9
(1) VOCs were re sampled because laboratory mrssed holding bme. (2) As of March 2012 both north and south wild life ponds no longer receiving water. (3) Chloroform pumping well started 6/9/15 .. NA;-n";t 'an'atvzed Shaded indicates concentrations eKceedinA GWQS. J = ApproKimated value
TABLE 1 (23 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
TW4-22 (nitrate pumping well started 1126113) Sampling Event
1stQtr 3/16/2005 2nd Qtr 5/25/2005 3rd Qtr 8/31/2005 4thQtr 12/7/2005 1stQtr 3/9/2006 2nd Qtr 6/14/2006 3rd Qtr 7/20/2006 4thQtr 11/8/2006 1st Qtr 2/28/2007 2nd Qtr 6/27/2007 3rd Qtr 8/15/2007 4th Qtr 10/10/2007 1st Qtr 3/28/2008 2nd Qtr 6/25/2008 3rdQtr 9/10/2008 4th Qtr 10/15/2008 11/18/2008 1stQtr 3/11/2009 2nd Qtr 6/23/2009 3rdQtr 9/14/2009 4th Qtr 12/29/2009 1si0tr 3/23/2010 2nd Qtr 6/14/2010 3rd Qtr 8/24/2010 4th Qtr 10/15/2010 1stQtr 2/22/2011 2nd Qtr 6/1/2011 3rd Qtr 8/17/2011 4th Qtr 11/16/2011 P/ 121712011 lsfcltr (2 1119/2012
2nd Qtr -6/13/2012 3rd Qtr 9/12/2012 4th Qtr 10/4/2012 1st Qtr (3) 2/11/2013 2nd Qtr 6/5/2013 3rd Qtr 9/3/2013 4th Qtr 10/29/2013 1stQtr 1/27/2014 2nd Qtr 5/19/2014 3rd Qtr 8/11/2014 4th Qtr 10/29/2014 1st Qtr 3/9/2015 2nd atr 6/8/2015 3rd Qtr 8/31/2015 4th Qtr 10/19/2015 1st Qtr 3/9i2016 2nd Qtr 5/23/2016 3rd Qtr 7/25/2016 4th Qtr 10/12/2016 1stQtr 3/8/2017 2nd Qtr 6/13/2017 3rd Qtr 7/26/2017 4th Qtr 10/11/2017 DWMRC solrt same le 1stQtr 3/12/2018 2nd Qtr 6/8/2018 3rd Qtr 8/22/2018 4thQtr 11/28/2018 1stQtr 3/8/2019 2nd Qtr 6/5/2019 3rd Qtr 9/4/2019 4thQtr 12/10/2019 1stQtr 2/19/2020 2nd Qtr 5/27/2020 3rd Qtr 9/4/2020 4thQtr 10/28/2020 1stQtr 2/23/202,-2nd Qtr 6/9/2021 3rdQtr 8/24/2021 4thQtr 12/1/2021 1stQtr 3/9/2022 2nd Qtr 6/8/2022 3rdQtr 8/30/2022 4thQtr 11/30/2022 1stQtr 3nl2023
Carbon Tetrachloride Chloroform ISua/Ll 170 un/L\
NA 340 <5.0 290 <5.0 320 <10 390 <10 280
<10 864 <1.0 350 <1.0 440 <1.0 740 <1.0 530 <1.0 440 <1.0 1.400 <1.0 1.200 1.3 6.300 NA #NIA <2.0 630 <1.0 390 <1.0 730 <1.0 2,300 <1.0 380 <1.0 2,200 <1.0 540 <1.0 340 <1.0 340 1.2 1.300 <1.0 210 <1.0 450 NA #NIA <1.0 400 <1.0 200 <1.0 ----,20<1.0 121 <1.0 330 3.24 ---w:soo 3.35 12,500 3.25 9,640 8.09 13,300 6.06 12,100 6.65 12,400 1.9 12.400 3.32 12,400 3.77 12.700 2.42 8,050 <1.0 7,810 3.3_� --------7,530 <1.0 6,070 2.64 8,570 <1.0 5,840 1.08 3,370 1.56 5,320 1.21 3.670 <1.0 5,150 <1.0 4,770 <38 4,100 <1.0 4,530 <1.0 3,010 <1.0 3.600 <1.0 2,680 1.02 4,310 1.13 4,690 <1.0 3,460 <1.0 3,820 1.02 3,910 <1.0 2,530 <1.0 3,760 6.83 3,640 <1.0 5,100 <1.0 4,520 <1.0 3,510 <1.0 3,330 <·1.o 3,320 <1.0 2,600 <1.0 3,190 <1.0 2,350 <1.0 1 900
( 1) VOCs were re sampled because laboratory m1Ssed holding bme.
DUSA Whrte Mesa Mill
Parameter
(GWQS)
Chloromethane Methylene Chloride 130 un/L\ 15 ua/Ll Monitor well was not installed NA NA <5.0 <5.0 <5.0 <5.0 <10 <10 <10 <10 <10 <10 1.6 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA NA <2.0 <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 -<·1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA NA <1.0 <1.0 <1.0 -<1.0 <T.O ______ <1.0 ------<1.0 <1.0 <1.0 <1.0 <T.O ______ <1.0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 2.83 <1.0 <1.0 40 <1.0 1.61 <1.0 4.31 <{'.o 3.42 <1.0 5.47 <1.0 5.1 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <60 150 J <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 4.4 <1.0 <1.0 <1.0 <1.0 1.6 <1.0 1.3
{2) As or March 2012 both north and south wild life ponds no longer re<:eiving water.
(J)Ctioroform pum�weUstarted 1'2.6/13 -------· NA = not analyzed Shaded indicates concentrations exceedinA GWQS. Bold and italics indicates the MDL exceeded the GWQS J = AoproXJmated value
Chloride No GWQS Ima/LI
NA NA 253 236 221 221 236 347 273 259 238 519 271 524 539 NA 177 177 391 175 427 134 130 134 114 138 120 174 NA 36 ------35
--------130 130 586 487 501 598 614 540 596 675 390 557 567 583 598 619 588 566 572 391 600 610 607 580 613 567 528 662 588 608 606 578 514 523 618 408 410 586 442 564 637 601 562
Nitrate, Nitrate + Nitrite 110 mg/LI
18.2 15.7 15.1 15.3 14.3 14.5 15.9 20.9 19.3 19.3 18.8 39.1 41.9 38.7 36.3 #N/A 20.7 20.6 40.3 17.8 36.8 19.0 15.0 16.0 18.0 17.0 15.0 19.0 #NIA 14.0 12.8 7.0
___________ 1j.p 58.0 50.2 29.7 45.2 54.6 47.2 41.5 54.9 692 47.1 64.7 56.1 31.1 58.4 61.3 61.5 69.8 70.8 66.1 80.1 79.0 62.3 72.5 55.4 75.7 71.9 83.9 72.5 59.9 57.7 60.5 64.8 64.9 69.6 89.3 35.1 68.8 40.4 45.0 69.9 62.0 49.1
TABLE 1 (24 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
TW4-23 Sampling Event
2nd Qtr 612712007 3rd atr 8/15/2007 4th Qtr 10/10/2007 1sl Qtr 3/2812008 2nd Qtr 6/2512008 3rd Qtr 9/1012008 4th Qtr 1011512008 11118/2008 1stQtr 3/412009 2nd atr 6/23/2009 3rd Qtr 911412009 4th Qtr 12/1612009 1statr 312412010 2nd Qtr 611412010 3rd Ctr 8/24/2010 4th Qtr 10/1512010 1stOtr 2/1612011 2nd Qtr 611412011 3rdQtr 8/1612011 4th Qtr 1111512011 1st 111712012 2nd Qtr 3rd Qtr 4th Qtr 1stOtr 2nd Qtr 3rd Otr 4th Qtr 1st Ctr 2nd Qtr 3rd Qtr 4th Qtr 1stOtr 2nd Qtr 3rd Qtr 4th Qtr Duolicate TW4•70 rt Qtr 2nd Qtr 3rd Qtr
Dupl1eate lW4•70 14th Qtr 1st ctr 1W4-70
3rd Ctr 4th Qtr
513112012 812912012 10/312012 2/712013 5130/2013 91512013 111712013 112312014 5/1912014 8113/2014 1012812014 3112/2015 6/812015 913/2015 10/28/2015
3/1612016 5/2612016 8/2312016
10112/2016 311512017
611512017 8/2/2017 1011012017 DWMRC SP.lit samole �st atr 311412018 nd Qtr 6/1312018
Dupl1eate TW4-70 3rd Qtr 8130/2018 1.th Otr 12/12/2018 1stQtr 3116i2iffii 2nd atr 611312019 3rd Qtr 911112019 4th Qtr 12/1012019 1s!Qtr 311712020 2nd Qtr 611112020 3rd Qtr 911712020 4th Qtr 1114/2020 1stOtr 311712021 2nd Qtr 6/1612021 3rd Qtr 9/1512021 4thQtr 12/812021 Duolicate TW4-70 1stQlr 3122/2022 Duplicate lW4•70 2nd atr 6/1612022 3rd Qtr 911412022
Carbon Tetrachloride 15uo/L)
<1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
1stQtr <1.0
Chloroform Chloromethane 170 uo/Ll 130 uo/L) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA NA <2.0 <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <l.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <2.0 <1.0 <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 4thQtr �<1.0
(1) As of March 201 rth and sooth wild life nds no lo er receiving: water. ---------------------po ---ng --------------NA = not analyzed Shaded indicates concentrations exceedinR GWQS. J = Approximated value.
Parameter IGWQS) Methylene Chloride 15 "o/Ll <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ________ <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1,0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <2.0 <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Nitrate, Nitrate + Nitrite No GWQS lmo/Ll 110 mg/Ll 47 <0.1 46 <0.1 43 <0.1 41 <0.1 41 <0.1 35 <0.05 51 <0.05 NA NA 41 <0.1 43 <0.1 43 <0.1 37 <0.1 4-5·�0.1 40 <0.1 40 <0.1 34 <0.1 44 <0.1 44 <0.1 41 <0.1 43 <0.1 40 <0.1 ----44 <0.1 46 <0.1 45 <0.1 43.6 <0.1 44.7 0.1 48 <0.1 43 <0.1 44.6 <0.1 42.3 <0.1 46 <0.1 46.8 <0.1 47.3 <0.1 48.4 <0.1 54.1 <0.1 46.4 <0.1 46.4 <0.1 49:1 <0.1 50.4 <0.1 49.6 <0.1 48.3 <0.1 52.1 <0.1 47.7 <0.1 49.8 <0.1 51.5 <0.1 51.8 <0.1 44.7 <0.1 52 <0.1 53.8 <0.1 47.6 <0.1 47.9 <0.1 56 <0.1 54.9 <0.1 48.9 <0.1 50.2 <0.1 47.9 <0.1 54.4 <0.1 50.0 <0.1 49.0 <0.1 48.8 <0.1 49.3 <0.1 51.6 <0.1 48.8 <0.1
42.8 <0.1 51.2 <0.1 53.2 <0.1 43.8 <0.1 39.2 <0.1 42.2 0.10 45.0 <0.1 47.5 <0.1 50.2 <0.1
TABLE 1 (25 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023
Chloroform Contamination Investigation OUSA White Mesa Mill
1W 4-24 (nitrate pumping well started 1/26/13) Sampling Event Carbon Tetrachloride 15 ua/LI 2nd Qtr 612712007 <1.0 3rd Qtr 8/15/2007 <1.0 4thQtr 10/10/2007 <1.0 1stQtr 3/28/2008 <1.0 2nd Qtr 6/25/2008 <1.0 3rd Qtr 9/10/2008 <1.0 4th Qtr 10/15/2008 NA 11/18/2008 <2.0 1stQtr 3/4/2009 <1.0 2nd Qtr 6/23/2009 <1.0 3rd Qtr 9/14/2009 <1.0 4thQtr 12/16/2009 <1.0 1stQtr 3/25/2010 <1.0 2nd Ctr 6/14/2010 <1.0 3rd Qtr 8/24/2010 <1.0 4th Qtr 10/15/2010 <1.0 'istair 2/16/2011 .<1.0 2nd Qtr 6/14/2011 3rd Ctr 8/16/2011 4th Qtr 11/15/2011 111 12/7/2011 1••"•U:t2L _ 111612012
2nd Qtr 6/6/2012 3rd Ctr 8/30/2012 4th Qtr 10/3/2012 1st Qtr (3) 2/11/2013 2nd Qtr 6/5/2013 3rd Qtr 8/30/2013 4th Qtr 10/29/2013 1st Ctr 1/27/2014 2ndQtr 5/19/2014 3rdQtr 8/11/2014 4th Ctr 10/21/2014 1stQtr 3/9/2015 2nd Qtr 6/8/2015 3rdQtr 8/31/2015 4thQtr 10/19/2015 1stQtr 3/9/2016 2nd Ctr 5/23/2016 3rdOtr 7/25/2016 4th Ctr 10/12/2016 1stQtr 3/8/2017 2nd Ctr 6/13/2017 3rdQtr 7/26/2017 4thQtr 10/11/2017 DWMRC snlit sam le 1stQtr 3/16/2018 2nd Ctr 6/14/2018 3rdQtr 8/22/2018 4thQtr 11/28/2018 OWMRC solit sam le 1stQtr 3/8/2019 2nd Qtr 6/5/2019 3rdQtr 9/4/2019 4thQtr 12/10/2019 1stQtr 2/19/2020 2nd Ctr 5/27/2020 3rdQtr 9/4/2020 4th Ctr 10/28/2020 1stQtr 2/23/2021 2nd Qtr 6/9/2021 3rd Ctr 8/26/2021 4thQtr 12/1/2021 1st Ctr 3/9/2022 2nd Ctr 6/8/2022 3rd Ctr 8/30/2022 4th Ctr 11/30/2022 Tstci"tr 3nt2023
<1.0 <1.0 NA <1.0 <1.0 -----------<1.0 <1.0 <1.0 <1.0 _________
<1.0 <1.0 <1.0 1.18 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <0.38 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloroform Chloromethane 170 uo/LI 130 uo/LI 2.6 <1.0 2.2 <1.0 1.5 <1.0 1.5 <1.0 1.4 <1.0 2.9 <1.0 #N/A NA <2.0 <2.0 1.4 <1.0 1.5 <1.0 1.4 <1.0 1.2 <1.0 1.3 <1.0 1.7 <1.0 1.8 <1.0 1.4 <1.0 1.8 <1.0
1.1 <1.0 1.7 <1.0 #N/A NA 1.2 <1.0 <1.0 <1.0 --------<1.0 <1.0 <1.0 <1.0 1 <1.0 -----, <T_o------17.4 <1.0 21.8 <1.0 32.5 <1.0 78.5 <1.0 62.7 <1.0 76.3 <1.0 25.8 <1.0 49.2 <1.0 4.28 <1.0 46.9 <1.0 25.3 <1.0 22.8 <1.0 69.6 <1.0 17.8 <1.0 20.8 <1.0 18.3 <1.0 17.2 <1.0 17.8 <1.0 16.0 <1.0 36.0 <0.60 24.9 <1.0 49.2 <1.0 35 <1.0 21 <1.0 60 <5.0 28.1 <1.0 28.8 <1.0 31.1 <1.0 43.3 <1.0 61.7 <1.0 49.4 <1.0 63.8 <1.0 72.6 <1.0 96.2 3.6 -41.9 <1.0 103 <1.0 112 <1.0 114 <1.0 124 <1.0 88.9 <1.0 79.5 <1.0 99.5 <1.0
(1) 1/OCs were resampled because laboratory missed holding time. (2) As of March 2012 both nortfl and south wild life ponds no longer receiving water.
(3)Chloroform_eumpin.,2weMstarted 1/26113 -------· NA:: not analyzed Shaded indicates concentrations exceeding GWQS. J = ApproXlmated value
Parameter
(GWQS)
Methylene Chloride (5 po/L) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 "<i·o <1.0
<1.0 NA <1.0 <1.0
<1.0-------<1.0 <1.0 <1.0 ------
<1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.3 J <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ·<fa
Chloride No GWQS (mo/LI 770 791 692 740 834 1.180 1.130 #NIA 1.010 759 618 1 080 896 639 587 522 1.100 1.110 967 608 #NIA 373 --------355 489 405 --------1,260 916 998 1.030 809 1,020 1.150 1.050 944 1.290 788 909 989 771 1.180 1.010 1.090 1.080 1.230 895 1,100 1.320 792 996 1.100 1,000 1.040 1.020 1.130 1.090 1.010 1.060 1.100 1.050 1.170 938 1.010 1.140 980 944 868 972 932
Nitrate, Nitrate+ Nitrite 110mg/L) 26.1 29 24.7 24.4 45.3 38.4 44.8 #N/A 30.5 30.4 30.7 28.3 33.1 30 31 31 31 35 34 35 #NIA ___________ 3'!_ 37 37
___________ 3� 35.9 23.7 33 35 31.6 35 0 31.5 35 7 34.6 31.8 25.3 29.6 -----29.1 24 2 34 4 31.9 41 3 39.9 40.0 31.7 32.0 44.9 33.6 33.8 38.4 34.0 39.3 33.2 36 4 33.8 37.1 41.7 39.1 35.9 41.9 48 0 26 7 43.6 36.2 35.0 32.0 27.6 36.2
�
TABLE 1 (26 of 33)
Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa MIU
1W4-25 (nitrate pumping well started 1/26/13) Sampling Event
2nd Qtr 6/27/2007 3rd Otr 8/15/2007 4thQtr 10/10/2007 1stQtr 3/28/2008 2nd Qtr 6/25/2008 3rd Qtr 9/10/2008 4th Qtr 10/15/2008 11/18/2008 1stOtr 3/4/2009 2nd Qtr 6/23/2009 3rd Qtr 9/14/2009 4th Qtr 12/16/2009 1stQtr 3/23/2010 2nd Qtr 6/14/2010 3rd Qtr 8/10/2010 4th Qtr 10/15/2010 1stOtr 2/16/2011 2nd Qtr 5/25/2011 3rd Qtr 8/16/2011 4th Qtr 11/15/2011 li!Otr !"L _ 1/16/2012 2nd Otr 5/31/2012 3rd Qtr 9/4/2012 4th Qtr 10/3/2012 1st Qtr(3) 2/11/2013 2nd Qtr 6/5/2013 3rd Qtr 9/4/2013 4th Qtr 10/31/2013 1stQtr 1/27/2014 2nd Qtr 5/19/2014 3rdQtr 8/11/2014 4thQtr 10/21/2014 1st Qtr 3/9/2015 2ndQtr 6/8/2015 3rd Otr 8/31/2015 4thQtr 10/19/2015 1stQtr 3/9/2016 2nd Otr 5/23/2016 3rd Qtr 7/25/2016 4thOtr 10/12/2016 1stQtr 3/8/2017 2nd Qtr 6/13/2017 3rdQtr 7/26/2017 4thQtr 10/11/2017 1stOtr 3/12/2018 2nd Qtr 6/14/2018 3rdQtr 8/22/2018 4thQtr 11�:1�g� 1stQtr 2nd Qtr 6/5/2019 3rdQtr 9/4/2019 4thQtr 12/10/2019 1stQtr 2/19/2020 2nd Qtr 5/27/2020 3rdQtr 9/4/2020 4thOtr 10/28/2020 1stQtr 21231202T 2nd Qtr 6/9/2021 3rdQtr 8/26/2021 4thQtr 12/1/2021 1stQtr 3/9/2022 2nd Qtr 6/8/2022 3rdQtr 8/30/2022 4thQtr 11/30/2022 1stQtr 3nt2023
Carbon Tetrachloride (5 µg/L) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 ---<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 -----------<1.0 <1.0 <1.0 <1.0 _________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ·<·1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloroform Chloromethane
170 ua/LI (30 ua/LI <1.0 <1.0 2.2 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 #N/A NA <2.0 <2.0 <1.0 <1.0 <1.0 <LO <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.8 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 --------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <T.O ____ <T.O ______
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <f:o <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ............ <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.15 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.15 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.34 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
( 1) VO Cs were resampled because laboratory missed holding time. (2) As of March 2012 both nortfl and south wild Hfe ponds no longer receiving water.
(=!i ChlofofOfm pumpi� weU started 1/26113 _______ • NA = not analyzed
Shaded indicates concentrations e)(ceed1ng GWQS.
Parameter
(GWQS)
Methylene Chloride (5 µa/L) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 ------<1.0 <1.0 <1.0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ·····---·-<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS (mg/L) 395 382 358 374 344 333 366 #N/A 3 328 328 371 296 306 250 312 315 321 276 294 304
--------287 334 338 --------190 136 119 88.6 85.7 51.1 67 58.1 310 58.3 69.2 93.7 ------------------62.7 75.5 74.1 59.8 285 69.8 70.1 68.0 70.5 60.3 69.1 59.7 65 59 58.1 73.1 86.0 76.8 67.3 61.3 foo 55.1 69.3 93.7 70.3 72.8 82.5 67.2 96.7
Nitrate, Nitrate + Nitrite (10mg/L) 17.1 29 17 18.7 22.1 18.8 21.3 #N/A 15.3 15 3 3.3 14.2 14.4 16 14 15 15 16 16 16 ___________ ,2 16 17 ___________ )I 9.04 5.24 5.69 6.1 2.16 1.21 1.6 1.03 14.4 1.14 1.63 1.78 0.837 0.959 1.78 1.24 17.0 0.976 1.23 1.29 2.23 1.14 0.810 0.634 0.639 0.821 0.548 0.841 0.607 0.851 0.994 1.64 3.43 1.57 0.793 0.978 1.8 0.88 1.51 1.47 1.96
TABLE 1 (27 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation OUSA White Mesa Mill
TW4-26 Sampling Event
2nd Qtr 6/14/2010 3rd Qtr 8/2412010 4thQtr 10115/2010 1stQtr 211612011 2ndQtr 5126/2011 3rdQtr 8/1712011 4th Qtr 11/16/2011
� 1217/2011 lsfO ( ,--1/18/2012 2nd Qtr -61612012 3rd Qtr 9/1112012 4th Qtr 10/312012 1st Qtr 211112·01:i 2nd Ctr 6/13/2013 3rd Qtr 9/512013 4th Qtr 11nl2013 1st Ctr 112912014 2nd Qtr 512112014 3rdQtr 811112014 4thQtr 1012812014 1stQtr 3/1212015 2nd Qtr 611012015 3rd Qtr 9/3/2015 4thQtr 10/28/2015 1stQtr 3/16/20fo" 2nd Qtr 512612016 3rd Qtr 81312016 4th Qtr 10/20/2016 1st Qtr 3/16120i'7 2nd atr 612012017 3rd Qtr 81312017 4th Qtr 10/1112017 1st Qtr 3/21/2018 2nd Qtr 6/14/2018 3rd Qtr 9/612018 4th Qtr 1211312018 1stQtr 3120/2019 2nd atr 6/5/2019 3rd Qtr 911212019 4th Qtr 12118/2019 1stQtr 3/18/2020 2nd Qtr 6/1212020 3rd Qtr 9119/2020 4th Qtr 1111112020 1st Qtr 3/2412021 2nd Qtr 6/17/2021 3rd Qtr 9/23/2021 4th Qtr 1219/2021 1stQtr 3/24/2022 2nd Qtr 612212022 3rd Qtr 9/15/2022 4th Qtr 1219/2022 1stQtr 3/29/2023 TW4-27 1stu1rl;'L ·-111812012 2nd Qtr 6/13/2012 3rd Qtr 9/4/2012 4th Qtr 10/3/2012 1stQtr 21712013 2nd Qtr 6/13/2013 3rd Qtr 8/30/2013 4thQtr 11/6/2013 1stQtr 1/23/2614 2nd Qtr 5/21/2014 3rd Qtr 8/13/2014 4thQtr 10/28/2014 1stQtr 3/11/2015 2nd Qtr 6/10/2015 3rdQtr 9/212015 4thQtr 10/28/2015 1stQtr 3/16/2016 2nd Qtr 5/26/2016 3rdQtr 8/3/2016 4thQtr 10/20/2016 1stQtr 3/15/2017 2ndQtr 6/15/2017 3rd Qtr 8/212017 4th Qtr 10/10/2017 1stQtr 3/1412018 2ndQtr 6/13/2018 3rd Qtr 8/3012018 4th Qtr 1211212018 ,-,fotr 3/16/2019 2nd Qtr 6/13/2019 3rd Qtr 9/1112019 4th Qtr 1211412019 1stQtr 3/1812020 2nd Qtr 611112020 3rd atr 9/18/2020 4thQtr 1114/2020 1stQtr 3/1812021 2nd Qtr 6/17/2021 3rd Qtr 9/15/2021 4thQtr 1218/2021 1stQtr 3/2312022 2ndQtr 6/16/2022 3rdQtr 9/14/2022 4thQtr 1218/2022 1statr 3/29/2023
Parameter IGWQS) Carbon Tetrachloride 15 ua/L) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <1.0 <1.0 <1.□--------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 -----------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloroform Chloromethane
(70 ualLl 130 ua/L) 13 <1.0 5.2 <1.0 5.4 <1.0 2 <1.0 2.9 <1.0 2.8 <1.0 #N/A NA 5.2 <1.0 7 <1.0 -----47 <T.O ______ 4.9 <1.0 4.9 <1.0 4.9 <1.0 2.12 <1.0 2.81 <1.0 3.37 <1.0 1.43 <1.0 4.23 <1.0 1.3 <1.0 2.45 <1.0 2.37 <1.0 6.12 1.17 4.77 <1.0 3.45 <1.0"i:ii <1.0 8.23 <1.0 4.42 <1.0 19.9 <1.0 ,_ 46.1 <1.0 244 <1.0 419 <1.0 608 <1.0 1,050 <1.0 960 <1.0 916 <1.0 1.050 <1.0 963 <1.0 1,070 <1.0 877 <1.0 1,070 <1.0 1,090 <1.0 1,140 <1.0 1120 <1.0 1,160 <1.0 1,030 <1.0 1.020 <1.0 927 <1.0 993 <1.0 952 2.4 790 <1.0 930 <1.0 890 <1.0 703 <1.0
9 <1.0 <T.O ____ <1.0 ______ <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.3 <1.0 1.6 <1.0 ...... 2.11 <1.0 3.16 <1.0 2.78 <1.0 3.8 <1.0 4.33 <1.0 5.65 <1.0 6.05 <1.0 5.91 <1.0 6.95 <1.0 5.95 <1.0 7.35 <1.0 7.7 <1.0 6.54 <1.0 8.24 <1.0 7.58 <1.0 7.97 <1.0 8.04 <1.0 7.92 <1.0 5.62 <1.0 7.8 <1.0 4.66 <1.0 4.26 <1.0 3.81 <1.0 4.08 <1.0 3.3 <1.0 3.1 <1.0 4.3 <1.0 2.3 <1.0 2.0 <1.0
(1) VOCs were resampled because laboratory mrssed holding time. (2) As of March 2012 both north and south wlld life ponds no longer receiving water. _____ _ NA = not analyzed Shaded ind+cates concentrations exceedmg GWQS
Methylene Chloride (5 ualL) <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 NA <1.0 <1.0 <1.0 -------<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1,0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 ----<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Chloride No GWQS lmolLl 33 17 22 30 15 19 26 #N/A 17 ---------19 19 19 16.6 14.5 17.6 15.9 16.9 15.4 15 14.6 14.4 14.4 14 13.3 13.7 15.2 13.9 14.2 16.2 19 25.8 27.3 35.5 33.5 38.9 33.4 32.9 35.8 32.0 38.3 36.3 35.1 34.8 36.3 38.9 34 36.5 34.9 33.0 34 36.7 32.7 :i4:s 11 ----17 21 18 18.8 20.3 19 21.8 31:s 20.6 23 24.4 26.2 26.8 26.8 26.2 ------------28 21.2 27.1 29.4 28.3 27.9 29.5 26.3 3oj 28.3 31.4 28.2 262 28.6 25.3 27.4 27.6 28.0 26.2 26.8 27.5 25.8 21.7 26.4 22.7 22.3 23.2 16.2 22.8
Nitrate, Nitrate + Nitrite 110 mg/Ll 7.9 9.0 9.6 10.0 10.0 11.0 10.0 #NIA ----------HO 12.0 9.0 12.0 12.5 13.6 11.7 15.9 14.2 12.5 10.8 12.3 14.4 11.3 14.2 13.9 ........ --iS:il 13.9 17.9 15.0 15.8 15.2 15.2 10.0 12.2 13.2 13 5 11.8 12.2 12.6 10.9 10.3 11:§ 11.1 10.5 11.9 11.3 14.2 12.1 8.15 10.9 9.9 10.3 10.4 10.5
__________ 2:io 41.0 37.0 36.0 31.2 29.4 27.2 29.8 313 31.1 27.0 28.2 26.5 24.0 20.9 23.5 25.0 28.7 21.8 19.3 22.2 23.8 20.0 21.5 19.5 22.0 18.1 20.8 21.5 22.3 21.2 22.0 23.6 21.5 25.2 16.7 --23.0 23.8 21.1 24.9 21.3 20.0 16.9 18.1 20.9
TW4-28 Sampling Event
TABLE 1 (28 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023
Chloroform Contamination Investigation OUSA White Mesa Mill
Parameter IGWQS) Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride
ISµa/L) 170 ua/Ll 130 µgill 15 uo/Ll No GWQS (mg/L)
2nd Qtr 6/19/2013 3rd atr 8/29/2013 4thQtr 11/612013 1stQtr 1/2212014 2ndQtr 5/21/2014 3rdQtr 8/13/2014 4thQtr 10/23/2014 1stQtr :iffii2015 2nd Qtr 6/10/2015 3rd Qtr 9/212015 4thQtr 10/21/2015 1stQtr 3/15/2016 Duplicate TW4-65
�2nd atr 5/25/2016 3rd Qtr 7/27/2016 Duplicate TW4-65 l4thQtr 10/19/2016 Oirilicate TW4-65 (1stQtr 3/14/2017 Duplicate TW4-65 2nd Ctr 6/14/2017 3rd Qtr 7/27/2017 4thQtr 10/10/2017 1st Ctr 3/14/2018 2ndQtr 6/12/2018 Duplicate TW4-65 3rd Qtr 8/29/2018 4thQtr 11/30/2018 1·stQtr 3/16/2019 2nd Qtr 6/13/2019 3rd Ctr 9/11/2019 4thQtr 12/12/2019 1st Ctr 3/17/2020
2nd Ctr 6/10/2020
3rd Ctr 9/17/2020 4th Qtr 11/4/2020 1st Qtr 3/17/2021 2ndQtr 6/15/2021 3rd Qtr 9/15/2021 4th Qtr 12/7/2021 1stQtr 3/15/2022 2nd Ctr 6/15/2022 3rd Ctr 9/13/2022 4th Qtr 12/7/2022 1statr 3/2212023 Du ticate TW4-65
TW4-29 2nd Qtr 6/19/2013 2nd Ctr 7/11/2013 3rd Qtr 9/26/2013 4thQtr 11/13/2013 1stQtr 2/5/2014 2nd Ctr 5/2212014 3rd Qtr 8/27/2014 4th Qtr 10/29/2014 1stQtr 3/1212015 2nd Ctr 6/11/2015 3rd Ctr 9/3/2015 4th Qtr _J_Q/29/2015 1st Ctr 3/17/2016 2nd Ctr 6/8/2016 3rd Qtr 8/3/2016 4th Qtr 10/26/2016 1st Ctr 3/16/2017 2nd Ctr 6/4/2017 3rd Ctr 8/4/2017 4th Qtr 10/11/2017
1st Ctr 3/14/2018 2nd Qtr 6/14/2018 3rd Qtr 8/29/2018 4thQtr 12/13/2018 1statr 3/20/2019 2nd Ctr 6/13/2019 3rd Qtr 9/12/2019 4thQtr 12/18/2019
1st Ctr 3/18/2020
2nd Ctr 6/12/2020 3rdQtr 9/19/2020 4thQtr 11/11/2020 i�''"'•m•le 3/24/2021 r 6/17/2021 9/23/2021 4thQtr 12/9/2021 lr-.., .. licateTW4-75 1stQtr 3/23/2022
2nd Ctr 6/2212022 JrdQtr 9/23/2021 DuplicateTW4-75 4thQtr 12/9/2022 1st0tr 3/29/2023
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <iO
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 242 <1.0 <1.0 262 <1.0 <1.0 246 <1.0
<1.0 260 <1.0
<1.0 258 <1.0
<1.0 262 <1.0
<1.0 242 <1.0 <1.0 290 <1.0 <1.0 299 <1.0 <1.0 329 <1.0 <1.0 276 <1.0 <1.0 631 <1.0 -----<1.0 --335 <1.0
<1.0 366 <1.0
<1.0 401 <1.0
<1.0 392 <1.0 <1.0 446 <1.0 <1.0 420 <1.0 <1.0 466 <1.0 <1.0 431 <1.0 <1.0 533 <1.0 <1.0 474 <1.0
<1.0 454 <1.0
<1.0 521 <1.0
<1.0 507 <1.0
<1.0 537 <1.0 <1.0 549 <1.0 <1.0 630 <1.0 <1.0 652 <1.0 <1.0 686 <1.0
<1.0 621 <1.0
<1.0 671 <1.0 <10 670 <20
<1.0 577 <1 .. 0
<1.0 543 <1.0
<1.0 602 <1.0 <1.0 625 <1.0 <1.0 636 <1.0 <1.0 624 <1.0 <1.0 398 <1.0
<1.0 591 <1.0
<1.0 591 <1.0
<1.0 588 <1.0
<1.0 467 <1.0
H =-Sam le was analyzed beyond holding times and may not be accureate concentration. Shaded indicates concentrations eKceed1ng GWQS
<1.0 44.6 <1.0 45.3 <1.0 45.3 <1.0 47.8 <1.0 45.7 <1.0 50
<1.0 52.1 <T.o 52.2 <1.0 56.4 <1.0 61.4 <1.0 52.7 <1.0 61.6 <1.0 61.4 <1.0 67.1 <1.0 70.1
<1.0 70.9
<1.0 70.9 <1.0 73.7 <1.0 64.2 <1.0 66.4 <1.0 68.6 <1.0 67.1
<1.0 57.4
<1.0 65.0
<1.0 55.7
<1.0 56.7 <1.0 63.8 <1.0 52.4 <1.0 51.7 <1.0 51.8
<1.0 49.0
<1.0 50.0
<1.0 52.1 <1.0 49.8 <1.0 47.4 <1.0 49.0 <1.0 51.8 <1.0 48.5 <1.0 40.7 <1.0 47.8 <f.o 38.8
<1.0 52.3
<1.0 58.5
<1.0 52.0 <1.0 46.1 <1.0 49.4
<1.0 44.8
<1.0 37.7
<1.0 41.4 <1.0 42.5 <1.0 14.9 <1.0 38.2 <1.0 41 <1.0 41
·:c1.o 40.5
<1.0 42.5
<1.0 47.3
<1.0 39.8 --------<1.0 ◄-o:s<1.0 42.9 <1.0 40.6 <1.0 44.2 <1.0 41.5
<1.0 42
<1.0 42.9
<1.0 37.7
.<f.O 43.1
<1.0 40.1 <1.0 45.9 <1.0 40.9 <1.0 39.9 <1.0 39.4
<1.0 38
<1.0 44.8
<1.0 41
<1.0 42.2
<1.0 39.9 <1.0 40.8 <20 42
<1.0 44.3 <1.0 40 <1.0 40.1 <1.0 38.7
<1.0 40
<1.0 39.1
<1.0 41.5
<1.0 41.8
<1.0 42.0 <1.0 41.3 <1.0 41.3
Nitrate, Nitrate + Nitrite (10mg/L) 14.9 17.3 16.2 16.9 16.5 14.2 16.5 19.0 19.0 17 8 18 7 34.0 32.6 29.0 31.3 35.6 25.5 25.4 24.4 27.9 26.0 24.8 24.8 17.2 19.0 18.7 16.0 17.7 17.2 15.0 10.2 9.48 9.87 9.55 8.36 7.76 8.68 9.09 8.08 7.60 ra-o 15.0 16.2 16.6 11.9 11.1 4.60 3.52 4.18 4.11 4.63 3.52 3.40 3.64 4.14 2.95 2.19 2.74 ----------2.92 2.51 2.44 2.40 2.24 2.26 2.35 2.45 2.44 2.67 2.52 2.50 2.67 2.56 2.55 2.58 3.10 3.18 2.90 3.27 0.75 H 3.09 3.59 3.29 2.39 1.91 3.10 2.9 2.80 2.76 2.69 2.74
TW4-30 Sampling Event
TABLE 1 (29 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023
Chloroform Contamination Investigation DUSA White Mesa Mill
Parameter
(GWQSI Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride (5 µg/L) 170 ua/LI 130 µa/L) (5 µg/L) No GWQS (mall)
2ndQtr 6/19/2013 <1.0 <1.0 <1.0 <1.0 36
3rdQtr 9/26/2013 <1.0 <1.0 <1.0 <1.0 36.3 4thQtr 11/13/2013 <1.0 <1.0 <1.0 <1.0 35.9
1stQtr 1/23/2014 <1.0 <1.0 <(o <1.0 36.9 2ndOtr 5/22/2014 <1.0 <1.0 <1.0 <1.0 31.9 3rdQtr 8/23/2014 <1.0 <1.0 <1.0 <1.0 38 4thQtr 10/23/2014 <1.0 <1.0 <1.0 <1.0 37.1 1st0tr 3/11/2015 <1.0 1.65 <1.0 <1.0 38.3 2ndQtr 6/11/2015 <1.0 2.25 <1.0 <1.0 40.3 3rd Qtr 9/3/2015 <1,0 3.27 <1.0 <1.0 44.2 4th Qtr·-······· 10/28/2015 <1.0 ----------------3.48 <1.0 <1.0 37.8 1stQtr 3/17/2016 <1.0 5.16 <1.0 <1.0 39.6 2nd Qtr 5/26/2016 <1.0 7.38 <1.0 <1.0 40.2 3rd Qtr 8/3/2016 <1.0 6.79 <1.0 <1.0 38.6 41hQtr 10/20/2016 <1.0 8.69 <1.0 <1.0 41.3 1stQtr 3/15/2017 <1.0 13.6 <1.0 <1.0 37.7 2nd Qtr 6/15/2017 <1.0 15.2 <1.0 <1.0 37.8 3rd Qtr 8/3/2017 <1.0 15.7 <1.0 <1.0 39.8 4th Qtr 10/10/2017 <1.0 13.4 <1.0 <1.0 34.9
1stQtr 3/15/2018 <1.0 16.4 <1.0 <1.0 41
2nd Qtr 6/13/2018 <1.0 16.9 <1.0 <1.0 37.4 3rd Qtr 8/30/2018 <1.0 19.8 <1.0 <1.0 44.1 4th Qtr 12/12/2018 <1.0 23.9 <1.0 <1.0 35.5 1stQtr 3/15/2019 <1.0 25.3 <1.0 <1.0 35.9 2nd Qtr 6/13/2019 <1.0 31.5 <1.0 <1.0 27.2 3rd Qtr 9/11/2019 <1.0 34.8 <1.0 <1.0 34.5 4th Qtr 12/18/2019 <1.0 44.9 <1.0 <1.0 39.1
1stQtr 3/17/2020 <1.0 53.1 <1.0 <1.0 37.5 2nd Qtr 6/12/2020 <1.0 65.4 <1.0 <1.0 38.6
3rd Qtr 9/18/2020 <1.0 67.7 <1.0 <1.0 35 4th Qtr 11/11/2020 <1.0 82.8 <1.0 <1.0 37.1
DWMRC snlit samnle <10 66 <20 <20 39 1stQtr 3/17/2021 <1.0 74.8 <1.0 <1.0 37.6 2ndQtr 6/17/2021 <1.0 78.7 <1.0 <1.0 38.3 3rd Qtr 9/22/2021 <1.0 78.2 <1.0 <1.0 23.5 4thQtr 12/8/2021 <1.0 81.2 <1.0 <1.0 37.9
1stQtr 3/23/2022 <1.0 73.6 <1.0 <1.0 35.1 2nd Qtr 6/22/2022 <1.0 70.8 <1.0 <1.0 41.3
3rd Qtr 9/14/2022 <1.0 68.8 <1.0 <1.0 30.5 4thQtr 12/9/2022 <1.0 60.5 <1.0 <1.0 36.5 isiatr 3/29/2023 <1.0 4s:s <1.0 <1.0 36.6
TW4-31 2ndOtr 6/19/2013 <1.0 <1.0 <1.0 <1.0 28.4
3rdQtr 9/5/2013 <1.0 <1.0 <1.0 <1.0 29.4 4thOtr 11n/2013 <1.0 <1.0 <1.0 <1.0 28 1st Qtr 1/23/2014 <1.0 <1.0 <1.0 <1.0 285 2ndQtr 5/21/2014 <1.0 <1.0 <1.0 <1.0 26.3 3rdQtr 8/13/2014 <1.0 <1.0 <1.0 <1.0 30 4thOtr 10/28/2014 <1.0 <1.0 <1.0 <1.0 37.1 ---1s1air----3/11/2015 <1.0 <1.0 <1.0 <1.0 30.6
2nd Qtr 6/10/2015 <1.0 <1.0 <1.0 <1.0 31.1 3rd Qtr 9/2/2015 <1.0 <1.0 <1.0 <1.0 30.4 4th Qtr 10/21/2015 <1.0 <1.0 <1.0 <1.0 29.1 1stQtr 3/11/2016 <1.0 <1.0 <1.0 <1.0 --3-u; 2nd Qtr 5/25/2016 <1.0 <1.0 <1.0 <1.0 32.5 3rd Otr 7/28/2016 <1.0 <1.0 <1.0 <1.0 30.6 4th Qtr 10/20/2016 <1.0 <1.0 <1.0 <1.0 34 1st Ctr 3/15/2017 <1.0 <1.0 <1.0 <1.0 31.3
2nd Qtr 6/15/2017 <1.0 <1.0 <1.0 <1.0 33.4
3rd Qtr 8/2/2017 <1.0 <1.0 <1.0 <1.0 33 4th Qtr 10/10/2017 <1.0 <1.0 <1.0 <1.0 30.9 1stQtr 3/14/2018 <1.0 <1.0 <1.0 <1.0 388 2nd Qtr 6/12/2018 <1.0 <1.0 <1.0 <1.0 34.4 3rd Qtr 8/29/2018 <1.0 <1.0 <1.0 <1.0 40.3 4thQtr 12/12/2018 <1.0 <1.0 <1.0 <1.0 35.2 1stQtr 3/16/2019 <1.0 <1.0 <1.0 <1.0 35 2nd Qtr 6/13/2019 <1.0 <1.0 <1.0 <1.0 36.9
3rd Qtr 9/11/2019 <1.0 <1.0 <1.0 <1.0 35.8 41h Qtr 12/14/2019 <1.0 <1.0 <1.0 <1.0 40.6 1stQtr 3/17/2020 <1.0 <1.0 <1.0 <1.0 38.2
2nd Qtr 6/12/2020 <1.0 <1.0 <1.0 <1.0 36.7 3rd Qtr 9/17/2020 <1.0 <1.0 <1.0 <1.0 36.5 41h Q1r 11/4/2020 <1.0 <1.0 <1.0 <1.0 36.4 1stQtr 3/17/2021 <1.0 <1.0 <1.0 <1.0 40.3 2nd Qtr 6/16/2021 <1.0 <1.0 <1.0 <1.0 37.9 3rd Qtr 9/15/2021 <1.0 <1.0 <1.0 <1.0 31.2 41h Qtr 12/8/2021 <1.0 <1.0 <1.0 <1.0 40.3
1stQtr 3/16/2022 <1.0 <1.0 <1.0 <1.0 34.3 2nd Qtr 6/16/2022 <1.0 <1.0 <1.0 <1.0 35.5 3rd Q1r 9/13/2022 <1.0 <1.0 <1.0 <1.0 40 4th Qtr 12/7/2022 <1.0 <1.0 <1.0 <1.0 31.8
1stQtr 3/16/2022 <1.0 <·1.0 <1.0 <1.0 35.6
Shaded md,cates concentrabons exceeding GWQS H = Sample was analyzed beyond holding times and may not be accureate concentration
Nitrate, Nitrate + Nitrite (10mg/L) 0.95 0.952 1.24 1.36 1.44 1.5 1.84 2.15 1.75 1.75 1.86 ... 2.74 2.04 2.32 2.51 2.70 2.95 3.11 2.58 3.63 3.93 3.79 3.70 ••·•---· 408 4.13 3.79 3.62 3.85 3.69 3.49 3.64
<0.5 H 3.54 4.19 2.60 3.14 3.0 2.8 2.61 2.67 2.84
1.3 1.1 1.33 1.32 1.22 1.1 1.84 1.33 1.19 0.916 0.953 1.84 1.36 1.41 1.14 1.19 1.21 1.11 1.04 0.916 0.948 0.710 0.766 ---0.7540.713 0.61 0.58 0.572 0.569 0.51 0.501 0.501 0.451 0.46 0.339 0.4 0.41 0.396 0.41 0.391
TW4-32 Sampling Event
TABLE 1 (30 of 33)
Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation
Carbon Tetrachloride (5 UQILJ
DUSA White Mesa Mill
Parameter fGWQSJ Chloroform Chloromethane Methylene Chloride Chloride 170 uo/Ll (30 ug/L) 15 ua/LJ No GWQS (mg/L) Nitrate, Nitrate + Nitrite (10 ma/LI
��g�:r,__r ___ 1c;;-'c;�c=��,���c';!�:]c-'o=-o---------1..::-!-]!i-�------1..::-!-]=-�----+'-:;c-'.�=----------1-----�;!'"•-!-�f-------�;"'�6"l1I2nd Qtr 5/21/2014 <1.0 <1.0 <1.0 <1.0 54.9 5.63 3rd Qtr 8/13/2014 <1.0 <1.0 <1.0 <1.0 64 4.2 4thQtr 10/23/2014 <1.0 <1.0 <1.0 <1.0 62.6+-------�2�.1--a4, '�1c"st�Q'"tr�--:iii-1,2015 <1.0 <1.0 <1.0 <1.0 64.2 2.46 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 65.9 2.25 2nd Qtr 6/10/2015 <1.0 <1.0 <1.0 <1.0 62.7 1.21 3rd Otr 9/2/2015 <1.0 <1.0 <1.0 <1.0 59.6 5.09 4th Qtr 10/21/2015 <1.0 <1.0 <1.0 <1.0 55.1 1.19 istQtr 3/15/2016-<1.0 <1.0 <1.0 <1.0 64.2 -i:48 2nd Qtr 5/25/2016 <1.0 <1.0 <1.0 <1.0 71.8 3.16 3rd Qtr 7/28/2016 <1.0 <1.0 <1.0 <1.0 64.4 3.44 4th Qtr 10/19/2016 <1.0 <1.0 <1.0 <1.0 66 2.871st Qtr 3/17/2017 <1.0 <1.0 <1.0 <1.0 62.8 2.82 2nd Qtr 6/15/2017 <1.0 <1.0 <1.0 <1.0 53.5 2.37 3rd Qtr 8/2/2017 <1.0 <1.0 <1.0 <1.0 65.8 2.47lf'4�th�Q'c't�r ___ 1'cc0"-/1,.,0'c/2,,:0_,_17:+'<-'-1.70 ______ f-<-'-1.70 __ ----,f-<71.70 ____ +-<-'-1.70 _____ -+-____ __,65.81--------"2"'.4"'17I 1st Qtr 3/14/2018 <1.0 <1.0 <1.0 <1.0 ss:;f 2.94 2nd Ctr 6/12/2018 <1.0 <1.0 <1.0 <1.0 59.2 2.51 3rd Qtr 8/29/2018 <1.0 <1.0 <1.0 <1.0 68.1 2.56
1�4=th�Q=t�r ___ 1�1�/3�0_,/2�0�18"+--<_,_1.=0 ______ ,_<1c,.0c._ __ l-'<:.,1c,.0c._ ___ -,.:<"-1."'0 _____ --1-------'5"-7"'.5+--------'2"'.5"'101 1stQtr 3/16/2019 <1.0 <1.0 <1.0 <1.0 57.5 2.15 2nd Qtr 9/11/2019 <1.0 <1.0 <1.0 <1.0 60.1 2.183rd atr 9/11/2019 <1.0 <1.0 <1.0 <1.0 55.0 1.84 4th Qtr 12/14/2019 <1.0 <1.0 <1.0 <1.0 64.7 1.89 1stQtr 3/17/2020 <1.0 <1.0 <1.0 <1.0 59.7 "·i.97 2nd Qtr 6/10/2020 <1.0 <1.0 <1.0 <1.0 57.0 2.19 3rd Qtr 9/17/2020 <1.0 <1.0 <1.0 <1.0 50.8 1.584th Qtr 11/4/2020 <1.0 <1.0 <1.0 <1.0 53.7 1.74 1st Qtr 3/17/2021 <1.0 <1.0 <1.0 <1.0 60.5 1.80 2nd atr 6/15/2021 <1.0 <1.0 <1.0 <1.0 40.4 2.31 3rd atr 9/15/2021 <1.0 <1.0 <1.0 <1.0 46.1 1.57 t-W g:; i�;�g�1 :1 g :1 g :; g :1 g ------!"'�""g=+---------c'1'="�6ci1
2nd Qtr 6/15/2022 <1.0 <1.0 <1.0 <1.0 49.4 1.20 3rd Qtr 9/13/2022 <1.0 <1.0 <1.0 <1.0 51.8 1.59 DuplicateTW4-65 <1.0 <1.0 <1.0 <1.0 53.6 1.81 i�� g:; ---1fil�m �::,11�•�:--------1�1 �------H8'-----'0�H�-----J------=:H1--------t�i
TW4-33 4th Qtr 11/14/2013 <1.0 1stQtr 1/30/2014 <1.0 2nd Qtr 5/22/2014 <1.03rd Qtr 8/27/2014 <1.0 4th Qtr 10/29/2014 <1.01stQtr 3/12/2015 <1.0 2nd Qtr 6/11/2015 <1.0 3rd Qtr 9/3/2015 <1.0 4th Qtr 10/29/2015 <1.0 ···-··---· 1stQtr 3/17/2016 <1.02nd Qtr 6/8/2016 <1.0 3rd Qtr 8/4/2016 <1.0 4th Qtr 10/26/2016 <1.0 1stQtr 3/17/2017 <1.0 2nd Qtr 6/20/2017 <1.0 3rd Qtr 8/3/2017 <1.04th Qtr 10/11/2017 <1.0 1stQtr 3/15/2018 <1.0 2nd Qtr 6/13/2018 <1.03rdQtr 9/5/2018 <1.0 4thQtr 12/13/2018 <1.0 1stQtr 3/20/2019 <1.0 2nd Qtr 6/19/2019 <1.03rd Qtr 9/12/2019 <1.0 4th Qtr 12/18/2019 <1.01stQtr 3/18/2020 <1.0 2nd Qtr 6/10/2020 <1.0 3rd Qtr 9/18/2020 <1.0 4thQtr 11/11/2020 <1.0 DWMRC s lit sam le <10 1stQtr 3/18/2021 <1.0 2nd Qtr 6/17/2021 <1.0 3rdQtr 9/22/2021 <1.0 4thQtr 12/8/2021 <1.0 1stQtr 3/23/2022 <1.0 2nd Qtr 6/22/2022 <1.0 3rd Qtr 9/14/2022 <1.0 4thQtr 12/9/2022 <1.0 1statr 3/29/2023 <1.0 Shaded mdK:ates concentrations exceeding GWQS
126 <1.0 <1.0 <1.0 --'-""+=-'""'-----P"'-------+-------'4'-'7"'.21-______ _,_1.�8,,,21 43.if 2.56
---···-··
--··-
124 <1.0 121 <1.0 104 <1.0 <1.0 <1.0 46.8 1.63 43 1.50 124 <1.0 <1.0 134 <1.0 <1.0 �c"'f=c------+�c--------+------=44.2 """·----"--"-"·-2.22 44.2 1.91 127 <1.0 123 <1.0 <1.0 <1.0 46.6 1.6253.3 1.64 129 <1.0 <1.0 ·1-'"""'-----P"'-------+--------44.5 1.92 122 <1.0 <1.0 46.2 2.13 96.1 <1.0 121 <1.0 109 <1.0 90.7 <1.0 103 <1.0 127 <1.0 97.1 <1.0 128 <1.0 87.8 <1.0 113 <1.0 141 <1.0 86.2 <1.0 121 <1.0 101 <1.0 117 <1.0 93.7 <1.0 90.1 <1.0 84.9 <1.0 80.6 <1.0 68 <20 64.9 <1.o 63.9 <1.0 60.2 <1.0 68.9 <1.0 53.1 <1.0 58.7 <1.0 53.9 <1.0 50.5 <1.0 47.7 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 . <1.0
49.7 2.064�5 2� 52.4 2.36 49.0 2.11 4�2 2M 4a9 2W 425 2� 4�2 1•444.0 2.13 50.0 1.82 43.2 2.01 4�2 200 43.4 2.16 �.1 1� 48.8 1.86 4�3 2« 48.9 3.2651.0 3.5851.5 3.71 54 0.12 55.6 4: 54.7 6. 42.5 4. 53.8 4. 51.4 3. 56.7 3. 42.2 3. 45.1 3 . 3.
H = Sample was analyzed beyond holding times and may not be accureate concentration.
TABLE 1 (31 of 33) Historic Summary Of Monitoring Well Analytical Res ults Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA While Mesa Mill
TW4-34 Sampling Event Parameter IGWQSl Carbon Tetrachloride (5 ua/Ll Chloroform Chloromethane Methylene Chloride Chloride Nitrate, Nitrate + Nitrite 170 pa/Ll (30 pg/L) (5 ua/Ll No GWQS (mg/L) (10 mo/LI i�� �'-;---1'"1"'!�"'f�,2 �1!1-:'-'1-'c.g'------........... -l ... :1·"'•g'-----l':'-'1"'•g'------+::-"1"'g-----+------'�5!.�."'·�-1-----1 �1 2nii oti 512212014 <1.o <1.0 ............ ·;,1.0 <1.0 17.9 . 1.69 3rdQtr 8/13/2014 <1.0 <1.0 <1.0 <1.0 18 1.10 i:g:; 1���;�g1:'-:'-'1�.g'---------,:1 g :1 g ---+:'-'1-'c.g'---------+------1'"�"'.�'l---------1"-•�"'l�I
2nd Qtr sh1i2Mi; <i:ii <1.0 <1.o <1.0 17.4 o.868 Qtr 913/2015 <1.0 <1.0 <1.0 <1.0 15.1 0.458
3rdQtr
1�!�i;�g1: :1 g N:·g"----12:"1""g-----1�1-·g.�------<-----�1��."�,__ _____ __,,�'.�� sasiiois .,.o <i:o .,.o .,.o 18 o:so5 8/3/2016 <1.0 <1.0 <1.0 <1.0 17.2 0.726
1����g1� :1.g :H ······ ·········· · ·l-:'c1c::g----+:c";c:cg-----1-- -
--�18°'1.i+--------"g"•:'"�4=121 siisi2oii .1:o .,.o <1.0 <1.0 iii) 0.121 8/2/2017 <1.0 <1.0 <1.0 <1.0 19.8 0.733 10/10/2017 <1.0 <1.0 <1.0 <1.0 18 .5 0.774 4�.L-----· �.Q .. _ _ __ _,_<.c.1�.o� __ _,_<.c.1=.o ____ J.<1.0 20.4 0.784 Qtr 3/14/2018 <1.0 <1.0 <1.0 <i:o 19.1 0.737 l Qtr 6/13/2018 <1.0 <1.0 <1.0 <1.0 19.5 0.877 Qtr 8/29/2018 <1.0 <1.0 <1.0 <1.0 23.8 O 736 g:; 1t1t�g;: :H ·· H:i---.. +:-.:1"'1""g-.----+:-'-;""g"--------1 ----�;�J············· ······ 1·1�l Qtr 6/13/2019 <1.0 <1.0 <1.0 <1.0 20.1 . Qtr 9/11/2019 <1.0 <1.0 <1.0 <1.0 17.8 O
1stQ 0"'�1'r'----'1"t"14""1!�g��1-:�1=g-------1:1.,.,,g---e':"1"'g-····························---i.::jJ ---+------c�cc�"ci+-------,��o
2nd Qtr 6/10/2020 <1.0 <1.0 <1.0 <1.0 20.9 1:240 3rd Qtr 9/17/2020 <1.0 <1.0 <1.0 <1.0 19.0 0.978
t�� g:; 1g;�g�� :1 g :1g :1 g :1"'g'------+------1'-":'"•�'-I-----· l�2nd Qtr 6/16/2021 <1.0 <1.0 <1.0 <1.0 17.8 1.08 3rd Qtr 9/15/2021 <1.0 <1.0 <1.0 <1.0 15.0 1.1 t�}g'"'t;----"!f"",:'2"',"2g"'�'"�•l-:021"'g'-----····-:1 g :1,g-----1:1,g�------<-----�1��.�"-+----. \Qi 2ndQtr 6/16/2022 <1.0 <1.0 <1.0 <1.0 19.5 1.0 3rd Qtr 9/14/2022 <1.0 1.2 <1.0 <1.0 18.8 0.788
!�:;�g�� �'"'1�.g'-------'"'•1..�-0'-----,_-2 ... :"1�gc_ ___ __,:tg:a-----��.� 1/� TW4-35 Qtr 8i21i26i4 <i:6 <1.0 <1.0 <1.0 ·· 34 · 0.2 41h .. .0:··Qt
J
1
..rr.
r
··
r· 10/28/2014 <1.0 <1.0 <1.0 <1.0 34.1 0.351 3/111201·5 <1.0 <1.0 <1.0 <1.0 34.9 0.436 6/10/2015 <1.0 <1.0 <1.0 <1.0 35.2 0.452 ... si3i2015 <1.0 <1.o·· <1.0 <1.0 35.9 0.304
1st Qlr 1�;�:�g1:· �1'.g"--------1-:; g :1 g"-----+:'-'1"'.g'------1------";H1---------"�'.m
2ncfQtr 5/26/2016 <1.0 <1.0 <1.0 <1.0 35_4 I..... 0.631 s,doir··· 51312016 .,.o .,.o <1.0 <1.0 34.8 0.123 4th Qtr 10/20/2016 <1.0 <1.0 <1.0 <1.0 37.1 0.626 isi Qtr 3/15/2017 <1.0 <1.0 <1.0 <1.0 33.7 . 0�673
2nd .. Qtr ... 6/15/2017 <1.0 <1.0 <1.0 <1.0 ,..... ........ 34.8 0.699 3rd Qtr 8/2/2017 <1.0 <1.0 <1.0 <1.0 36.3 ·· if········ 1=10/10/2017 <1 0 <1.0 ........ c:<cc1."'0 ____ .. :}"'g----31.7 n ·�lfit t! l"l"-!----�·�l:l=-------t-----�I='!� !.
··siii12019 .,._o ·· •i:o···· .,.o .,.o ··31.1 o. Qtr 12/14/2019 <1.0 <1.0 <1.0 <1.0 37.4 n
1st Qtr 3/17/2020 <1.0 <1.0 <1.0 <1.0 34.5 o. 2nd Qtr 6/11/2020 <1.0 ..... <1.0 ............. . <1.0 ............................. <J.O. 34.0 0. 3rd Qtr 9/17/2020 <1.0 <1.0 <1.0 <1.0 32.2 0. 4thQlr 11/4/2020 <1.0 <1.0 <1.0 <1.0 30.4 0. ,·.ratr 3/17/2021.<{0 <1.0 <1.0 <1.0 35.6 0.9
2nd Qtr 6/16/2021 <1.0 <1.0 <1.0 <1.0 34.1 1.C 3rdoi,······· 911512021 .1.0 •1.0 <1.0 .,.o 21.5 ,. 4thQtr 12/8/2021 <1.0 <1.0 <1.0 <10 34.3 U isiotr ··31221�20"'2=2+<�1"c.oc-------+.-'-1".oc----+.c:c,cc_o"------1.1•0�-----. 2°7:8 ... 1.
2nd Qtr 6/16/2022 <i:O <i:o <1.0 <1.0 31.2 1. oir 9i,4i2622 <1:0 <di <1.0 <1.0 34.4 H
12/7/2022 <1.0 <1.0 <1.0 <1.0 27.4 1.i 3/29/2023 <1.0___ <1.0 <1.0 <1.0 33.8 ......... .,.,,
IVV4-J6 3rd Qtr 8/27/2014 <1.0 <1.0 <1.0 <1.0 65 <0.1 1� g:; · 1���;�g1: :1 g'-----.-.......... --1 ..... 11'.� :1 g 1�"'g-----�H ·· ··············· · ·· :t12iiiioi, eiioi2015 <i.o .,.o <i.ci .,:o ·· 69.3 <o:i 3rdQtr 913/2015 <1.0 <1.0 <1.0 <1.0 76.4 <0.1 �!!l-�=:;---1���;�;;�g;� :; g :; g :; 0�0----+:'"';�g�-----1------'f�1�;�-------:"'g�;+ll Qtr 5/26/2iiie··•1.0 .<1.0 <1.0 <1.0 72.3 <0.1 Qtr 7/28/2016 <1.0 <1.0 <1.0 <1.0 69.4 <0.1 Qtr 10/20/2016 <1.0 <1.0 <1.0 <1.0 73.8 <0.1
');�7�:TW=•=-'•?,,_O-;c3/;s-15"'J2"'0"1�7 :tg :; g :; g :; g 6ci.�l--------2:gJ I Qlr 6/15/2017 <1.0 <1.0 <1.0 <1.0 71.3 <0.1 Qtr 8/2/2017 <1.0 <1.0 <1.0 . <1.0 69.6 <0.1 ��� g:; 1�;;��g1! :; g :; g 1}"-g----�·]}g�-------1-----����.�:1---------"0"-'�6!c"0;Jil
2ndQtr 6/12/2018 <1.0 <1.0 <1.0 <1.0 64.3 <0.1 3rd Qtr 8/29/2018 <1.0 <1.0 <1.0 <1.0 76.4 <0.1 ��,..;---1'-;f"',1'-c'�g1: :1g :tg :;•g :1g 6�: -· lH�2ndQtr 6/1312019 <1.0 <1.0 <1.0 <1.0 71.5 <0.1 3rdQtr 9/11/2019 <1.0 <1.0 <1.0 <1.0 69.6 <0.1 ,Cit, 12i14/2019 <1.0 <1,0 <1.0 <1.0 73.7 <0.1 3/17/2020 <1.0 <1.0 <1.0 <1.0 69.1 <0.1 Ctr lQtr Qlr Qtr 1s1Qtr 2ndQtr 3rd Qtr 4thQlr isfoir
2ndQtr
6/11/2020 <1.0 <1.0 <1.0 <1.0 67.0 <0.1 9/17/2020 <1.0 <1.0 <1.0 <1.0 66.0 <0.1
11/4/2020 <1.0 <1.0 <1.0 <1.0 64.0 <0.1 . 3/17/2021 <1.0 <1.0 <1.0 <1.0 72.5 <0.1 6/16/2021 <1.0 <1.0 <1.0 <1.0 68.7 <0.1 9/15/2021 <1.0 <1.0 <1.0 <1.0 63.1 <0.1 12/8/2021 <1.0 <1.0 <1.0 <1.0 69.9 <0.1 3/16/2022 <1.0 <1.0 <1 .0 <1.0 612 . 0.1 6/15/2022 <1.0 <1.0 <1.0 <1.0 68.8 <0.1 9/13/2022 <1.0 <1.0 <1.0 <1.0 69.3 <0.1 12iii2022 .1.0 .,.o .,.o ---+•'-'1.,,:0,_ ____ -+------'59_1 <o., 312312023 ·.,:o···<1.0 .. ,.o <1.0 tio.7 0.102
Shaded 1nd1cates concentrations exceedrng GWQS.
TABLE 1 (32 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill
TW4-37 (chloroform pumping well 619115) Parameter (GWQS)
Sampling Event Carbon Tetrachloride
(5 µg/L)
Chloroform Chloromethane Methylene Chloride Chloride Nitrate, Nitrate + Nitrite (10mg/L) (70 µg/L) (30 µg/L) 15 µo/L) No GWQS (mg/L)
2ndQtr 6/8/2015 18.2 30,200 15.7 1.94 345 35.2
3rdOtr 9/3/2015 16.6 19,100 13.7 1.04 374 32.4 �;�g:; 10;�:;�g;� ;;� ....... ;�;gg,------'-;.�;��l---•--··•--';'-'!-'-:-1------·--;;� ····················------";c:!c:c<J�
2nd Qtr 512312016 14.4 16.200 3.57 1.17 389 27.9
3rd Qtr 712512016 16.7 15,900 <1.0 <1.0 294 33.4 4th Qtr 10112/2016 16.3 16.400 <1.0 <1.0 304 26.1
1st Qtr 31812017 ...... 15.4 ··················1a.666 3.57 1.34 305 ·32.:i
2nd Qtr 611512017 16.2 15,800 <1.0 <1.0 281 31.2
3rd Qtr 712612017 15.1 15,000 <1.0 <1.0 277 30.5 ie��;he_tg=:"-;--�1��;�;1i�12�g�;��1------:�� --:���:��g�gl----���I :;g ��1··� --------";��
2nd atr 61812018 10.6 14.400 <1.0 <1.0 275 28.6
3rd Qtr 8122/2018 12.1 14,100 6.2 <1.0 387 25.3 4thOtr 1112812018 11.3 15.200 19.8<1.0 264 27.3 1stQtr 31812019 --····-.. fie -··········13,:i66 1.24 <1.0 209 ·30.1
2nd Qtr 61512019 14.6 16,200 <1.0 <1.0 250 31.2 3rdQtr 91412019 10.7 11.900 1.9<1.0 228 25.8
4th Qtr 1211012019 8.81 13,100 3.12 <1.0 220 25.5
1st Qtr 211912020 8.53 12,066 12.3 <1.0 236 · 28.3 2ndOtr 512712020 11.8 11.700 1.44 <1.00 321 28.3
3rd Qtr 91412020 9.62 13,800 <1.0 <1.0 273 29.5 11'4""the_O,,_t,,_r __ --"10""12,,,8"'12,,,0c'2�01-�-----"6"'.5""2+--__ 10,300 29.4 <1,0 254 28.7
1st Qtr 212312021 <1.0 9:380 <1.0 <1.0 242 26.9
2nd Qtr 61912021 8.46 13,000 1.98 <1.00 176 26.6 3rdQtr 812412021 7.65 10.200 <1.0 <1.0 220 25.8 �-g:; 1f�;}�l}1-----··HJ1---�;1�:��g�g+-<-1-.0---�5 ·�71-<-1-.0---�59I1------:�:-=-4� ;!�
2nd Qtr 61812022 8.2 46.800 12 <1.0 276 28.0 3rd atr 813012022 5.4 11.600 2.4 <1.0 243 26.6 4th Qtr 1113012022 5.7 9.640 <1.0 <1.0 578 30.9
1stQtr 3[7{2023 <1.0 8·010 <1.0 <1.0 209 19.1
TW4-38 4thQtr 1111012016<1.0 <1.0 <1.0 <1.0 40 11.2 1stQtr 3/15/2017 <1.0 <1.0 <1.0 <1.0 35.7 10.6 2nd Qtr 6/15/2017 <1.0 <1.0 <1.0 <1.0 36.2 10.8 3rd Qtr 8/2/2017 <1.0 <1.0 <1.0 <1.0 36.9 10.1
4th Otr 101101""20�1c.,7+<_1�.o,_ _____ +<_1�.o�--+<_1�.o�----i<1.0 31.3 10.3 101=st�a=t�r----'-':i1i412018 <1.0 <1.o <1.0 <1.0 36.5 9.34 2nd Qtr 6/13/2018 <1.0 <1.0 <1.0 <1.0 33.1 9.48 3rd Otr 8/3012018 <1.0 <1.0 <1.0 <1.0 39.2 7.77
4th Qtr 1211212018 <1.0 <1.0 <1.0 <1.0 35.0 8.48
1stQtr 311612019 <1.0 <1.0 <1.0 <1.0 33.5 8.96 2nd Qtr 611312019 <1.0 <1.0 <1.0 <1.0 33.7 8.53
Duphcate TW4-70 3rd Qtr
4th Qtr 1stQtr
2ndQtr 3rd Qtr
4th Qtr 1st Qtr
2ndQtr
<1.0 <1.0 <1.0 <1.0 35.3 9.52
9/1112019 <1,0 <1.0 <1.0 <1.0 31.6 7.61
1211412019 <1.0 <1.0 <1.0 <1.0 --1------�3"6+--______.!..7"",5�11 311712020 <1.0 <1,0 <1.0 <1.0 33.4 8.11
611112020 <1.0 <1.0 <1,0 <1.0 34.9 9,00 9/1812020 <1.0 <1,0 <1.0 <1.0 34.7 7.35 111412020_,_<...,1-".o� _____ .,_<�1"'.o� __ .,_<-'1�.o�----+<-'1_,.o'-------+------'3�5"-.1+--------'1�.1�2,, 3/1812021 <1.0 <1.0 <1,0 <1.0 37.2 8.24
611612021 <1.0 <1.0 <1.0 <1.0 37.7 9.59 DuphcateTW4-70 <1.0 <1.0 <1.0 <1.0 35.7 9.05
3rdOtr 911512021 <1.0 <1.0 <1.0 <1.0 32.1 8.04 '"i�;��g=:�;--'--!���t�l��g=��'-+-:�;�g------i-:J�'-----+:-';�g�----+:-';-'g'-------+------';���.�'+---------'8�1�.�a1 2nd Qtr 6/16/2022 <1.0 <1.0 <1.0 <1.0 37.3 7.9
3rdQtr 9/14/2022 <1.0 <1.0 <1.0 <1.0 32.9 7.57 4th Qtr 121112022 <1.0 <1.0 <1.0'-------+<'-'1_,.o'-------+------'3'"'-6.41---------"'8.'"9' 1st Qtr 312912023 <1.0 <1.0 <1.0 <1.0 37.2 8.78
TW4-39(chloroform pllmpir,g well
4thQtr
1stOtr 2nd Qtr 3rd Qtr 4th Qtr
1stOtr
,nn,,� 111112016 ic<c:1·.o------J"'._-_-_-_-...,.,2;;.8go,goi<]1].0Z�������_::'t<l1-'-'.·o�����������t����������]6J8J.9,!::::::::;;;::;:.;2Jo,jl. 7.Ji
31812017 8.15 6.460 <1.0 1,35 130 6.44 611512017 8.2 5.560 <1,0 1.31 120 6.25
16;��;;gg"'<"'1"c.O___ 14.4 10 -·"'��"'�'+<.:.<;'-"g"-----+<'-'1"'.0'---____ 1_.5
+-_____ 7,_,i""
3;'+--------';"".""�:'ll 3112/2018 3.1 2,870 <1,0 <1.0 118 3.33 2nd Qtr 61812018 7.94 7,160 <1.0 <1.0 107 4.84 3rd Qtr 8/22/2018 12.5 8,180 2.33 <1.0 110 6.05 �·c'g�:;--�1-'-'1;cc�:=";;='gc-';c:c�+-------'6"1o'c_�+--'--6�,���c:'�t-<�l�.oc---�203,J. :; g 1:i·<-------���.�"":'
2nd Qtr 3rd Qtr
4th Qtr 1stQtr
2nd Otr 3rd Qtr
4th Qtr 1stQtr 2nd Qtr 3rd Qtr
4th Qtr 1statr
61512019 11.6 8,640 <1,0 <1.0 114 8.45 91412019 5.71 4,240 <1.0 <1.0 48.2 1.75 1�;�;;g}i'•<-1�.oc------1�.1�4+--�1 ���1-:'-';-"g'-------+:'-';"'g'-------+-----"�"':-c.�+-------0'"0='1�c"l�1 512712020 7.56 5,870 <1.0 <1.0 88.5 5.01 9/1812020 8.18 5.960 <1.0 <1.0 63.21 2.69
1012812020 <1.0 __ _,6,:40,8-1-1ec.1c,9'-----+<'-'1"".0'-------+------'8"'3'-'.2'+--1 ______ _,7c,.0"'131212a12021 <1.0 2,910 <1.0 <1.0 53.o l 2.12 61912021 7.56 2,490 <1.0 <1.0 123 ___ �-12.0 812412021 <1,0 858 <1.0 <1.0 78.7 2.70
121112021 <1.0 776 <1,0 <1.0 82.4 2.33
31912022 <1.0 724 <1.0 <1.0 75.2I 2.9
2nd Qtr 61812022 1.4 982 <1.0 <1.0 76.8 9.0 3rd Qtr 813012022 <1.0 843 <1.0 <1.0 85.�I 3.72 "i��h�t""gt�t;--�1�1;""'�;;ii<1.0
1'2 ;��g:;g :;g �g� i��
Shaded indicates concentrations exceeding GWQS.
TW4-40 (chlorofOfm pumping well 5/2019) Sampling Event
TABLE 1 (33 of 33) Historic Summary Of Monitoring Well Analytical Results Up To The 1st Quarter 2023 Chloroform Contamination Investigation DUSA White Mesa Mill Parameter (GWQS)
Carbon Tetrachloride Chloroform Chloromethane Methylene Chloride Chloride 15 ua/L) (70 ua/LI 130 ua/LI (5 µg/L) No GWQS Ima/LI 1stQtr 3/2112018 2nd Qtr 6/1312018 3rd Qtr 9/512018 4th Qtr 12/12/2018 4-75 3120/2019 2nd Qtr 61512019 3rd Qtr 91412019 4th Qtr 12/10/2019 1s!Otr 2i19/2020 2nd Qtr 5/27/2020 3rd Qtr 9/4/2020 4thQtr 10/2812020 1stQtr 2/23/2021 2nd Qtr 619/2021 3rd Qtr 8/24/2021 4th Qtr 12/112021 1st Ctr 31912022 2nd Qtr 61812022 3rd Qtr 8/3012022 4th Qtr 11130/2022 1st Qtr 3/7/2022
TW4-41 (chlofoform pumping �u
2nd Qtr 5/812018 3rd Qtr 8/22/2018 4th Qtr 1112812018 1stQtr 3/812019 2nd Qtr 615/2019 3rd Otr 9/412019 4th Qtr 12/10/2019 1st Qtr 2/19/2020 2nd Otr 5/27/2020 3rd Qtr 9/4/2020 4thQtr 10/28/2020 1stOtr 2/2312021 2nd Qtr 619/2021 3rd Otr 812412021 4th Qtr 12/112021 1stQtr 3/912022 2nd Qtr 6/8/2022 3rd Qtr 8/30/2022 4th Qtr 11/30/2022 1sIQtr 3f7/2023 TW4-42 2nd Otr 3rd Qtr 4thQtr
O�pJicate _ TW4-75 1stQtr 2nd Otr 3rd Qtr 4th Qtr 1stQtr 2nd Qtr 3rdQtr 4thQtr 1s!Otr
Duplicate TW4-65 2nd Qtr 3rd Qtr 4thQtr 1st0tr
6/19/2019 9/11/2019 12/1012019
2/1712020 6/1012020 9/1712020 1114/2020 3/1712021 6/15/2021 9/15/2021 12/9/2021 3/1512022
6/15/2022 9/1312022 12/712022 3/22/2023 TW4-43 4th Otr 12/9/2021 1Statr 3/1712022 2nd Qtr 6/16/2022 3rd0tr 9/13/2022 4thQtr 12/7/2022 1stQtr 3/23/2023
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 ----
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Shaded indicates concentrations exceeding GWQS. (� ChlOfofOfm pum!Qg �el started in Ma1,2019 ------·
248 <1.0 131 <1.0 116 <1.0 118 <1.0 119 <1.0 111 <1.0
380 <1.0 314 <1.0 364 <1.0 367 <1.0 333 <1.0 264 <1.0 436 3.51 343 <1.0 301 1.32 286 <1.0 238 <1.0 323 <1.0 302 <1.0 298 <1.0 259 <1.0
1.400 <1.0 1,390 <1.0 1.320 <1.0 1.220 1,320 <1.0 1.190 <1.0 1.410 <1.0 1.200 <1.0 1.220 <1.0 1,110 <1.0 1.020 <1.0 1.170 <1.0 1,130 <1.0 1,100 <1.0 1,030 <1.0 1.030 <1.0 1,010 <1.0 1,060 <1.0 1.050 <1.0 985 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <·1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0
<1.0 ________
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1�0
35.7 31.6 37.6 29.9 32.3 30.9 35.6 35.9 36.7 38.5 36.5 34.2 34.6 36.0 27.5 31.8 38.4 36.8 36.6 39.3 44.8 23.5
42.8 45.5 41.4 39.1 38.1 39.4 42.1 44:4· 41.7 40.2 39.7 40.6 39.5 37.1 43.2 37.3 41.1 41.9 38.0 34.4
23.3 20.6 22.6 22.6 23.2 23.1 23.5 22.4 24.2 24.6 16.6 24.2 21.5 17.7 24.0 15.6 36.4 21.2
40.6 39.I 41.8 43.1 40.7 28
Nitrate, Nitrate+ Nitrite 110mg/L) 3.08 3.33 3.22 3.54 3J_8 3.18 3.55 3.39 2.89 2.98 2.91 2.88 2.58 2.43 3.77 1.50 2.60 2.5 1.90 2.22 2.24 1.28
6.54 6.13 6.02 6.71 6.00 6.22 6.11 6.12 6.78 6.69 6.25 6.41 7.45 3.77 6.72 6.2 6.0 5.92 6.0 4.3
2.57 2.75 2.82 2.95 2.88 3.23 3.65 2.77 3.15 3.57 3.26 2.02 2.5 2.6 3.3 3.3 2.02 2.8
0.118 0.4 0.24 0.383 0.383 0.384
Parameter GWQS
Chloride none Nitrate+ Nitrite (as N) 10 mg/L Chloroform 70 µg/L Carbon tetrachloride 5 µg/L Chloromethane 30 µg/L Methvlene Chloride 5 11n/L
nc = not calculated
Table 2 Summary of EFR QA/QC Samples
1st Quarter 2023
Duplicate Samples of Wells Duolicate of TW4-28 Duplicate of TW4-9 TW4-28 TW4-65 RPD TW4-9 TW4-70 RPD 46.1 49.4 -6.9 37.1 36.4 1.9 11.90 11.1 7.0 0.765 0.743 2.9 <1.0 <1.0 nc 6.2 5.6 10.2 <1.0 <1.0 nc <1.0 <1.0 nc <1.0 <1.0 nc <1.0 <1.0 nc <1.0 <1.0 nc <1.0 <1.0 nc
High lighted exceeding PRO (Relitve % difference) of 20%
Duplicate of TW4-16 TW4-16 TW4-75 RPD
88.5 92.5 -4.45.69 5.09 11.1 179 178 0.6 <1.0 <1.0 nc <1.0 <1.0 nc <1.0 <1.0 nc
Well ID MW4 MW-26 TW4-1
lbs of chloroform removed 0.8 0.1 0.06
total lbs of chloroform removed 5.9
Tabel3
Chloroform Mass Removal Calculations for the 1st Qurater 2023
EFR White Mesa Mill, Bland, Utah
TW4-2 TW4-4 TW4-11 TW4-19 TW4-21 TW4-22
0.07 0.1 0.03 0.3 0.4 0.3
1 ) Assuming that the chloroform concentration result for the quarter monitoring event is the average chloroform concentration for the entire quarter.
TW4-24 TW4-25 TW4-37 TW4-39 TW4-40 TW4-41
0.063 0.00 3.0 0.6 0.10 0.1