DRC-2011-002031 - 0901a0688020598e

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ELRC-201 1-002031 INTERA Incorporated
6000 Uptown Blvd, NE
Suite 220
Albuquerque, NM 87110
Telephone: [phone]
Fax: [phone]
VIA E-MAIL AND FEDERAL EXPRESS
February 18,2011
Mr. Loren Morton, Section Manager
Division of Radiation Control
Utah Department of Environmental Quality
168 North 1950 West
P.O. Box 144810
Salt Lake City, UT 84114-4810
Re: Work Plan and Schedule for Supplemental Contaminant Investigation Report for
White Mesa Mill Nitrate Investigation, Blanding, Utah
Dear Mr. Morton,
Enclosed is the revised copy of the above-referenced Work Plan and Scheule dated February 18,
2011. Also included is a CD containing a copy of the document in word searchable PDF format.
This document supersedes the document of the same title dated and submitted February 14,
2011. This version of the document contains revisions to Figure 20 to include items you
requested at our February 14"^ meeting and additional language on our QA/QC procedures for
the stable isotope study.
As agreed, this Work Plan will be e-mailed today and FEDEXed for delivery on Monday
February 21, 2011. Please do not hesitate to contact me at [phone] or Dave Frydenlund at
303-389-4130 if you have any questions or require further information.
Sincerely,
INTERA, Incorporated
Daniel W. Erskine, Ph.D.
Principal Geologist/Geochemist
Enclosures
FILE: lUC-002-01

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Blanding, Utah

Prepared for:

Denison Mines (USA) Corp.
1050 17th Street, Suite 950
Denver, Colorado 80265

Prepared by:

6000 Uptown Boulevard NE, Suite 220
Albuquerque, New Mexico 87110
February 18, 2011

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TABLE OF CONTENTS
LIST OF FIGURES ...................................................................................................................... ii
LIST OF TABLES ........................................................................................................................ ii
LIST OF APPENDICES .............................................................................................................. ii
ACRONYMS AND ABBREVIATIONS .................................................................................... iii
1.0 INTRODUCTION............................................................................................................. 1
1.1 Historical Land Use and Geomorphologic Study ................................................... 3
1.2 Investigation of Potential Natural Nitrate Reservoir .............................................. 3 1.3 Investigation of Potential Nitrate Source Locations ............................................... 4 1.4 Stable Isotope Study ............................................................................................... 4
1.5 Mass Balance Calculations ..................................................................................... 6
2.0 GEOLOGY AND HYDROGEOLOGY .......................................................................... 7
3.0 PROJECT MANAGEMENT ........................................................................................... 8
3.1 Field Documentation ............................................................................................... 8 3.2 Health and Safety .................................................................................................... 8
4.0 HISTORICAL LAND USE AND GEOMORPHOLOGIC STUDY ............................ 9
4.1 Initial Procedure ...................................................................................................... 9
4.2 Initial Conclusions and Recommendations ........................................................... 10
5.0 INVESTIGATION OF NATURALLY OCCURRING NITRATE RESERVOIR IN SOIL............................................................................................................................ 12
5.1 Geoprobe Nitrate and Chloride Investigation ....................................................... 13
5.2 Coring Study to Explore for Natural Nitrate Reservoir ........................................ 15
6.0 INVESTIGATION OF POTENTIAL NITRATE SOURCE LOCATIONS ............. 17
6.1 Geoprobe Investigation of Potential Nitrate Source Locations ............................ 17 6.2 Coring Study in Potential Nitrate Source Locations ............................................. 19
7.0 STABLE ISOTOPES STUDY ....................................................................................... 20
7.1 Quality Assurance and Quality Control Procedures ............................................. 23
8.0 MASS BALANCE CALCULATIONS .......................................................................... 24
9.0 REFERENCES ................................................................................................................ 26

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LIST OF FIGURES
Figure 1 Flow Chart Depicting the Logical Progression of Additional Studies
Figure 2 δ15N results from Sampling of Various Sources of Nitrate Contamination Figure 3 δ15N Results Normalized to N2 in the Atmosphere from Sampling a Wider Range of Sources
Figure 4 A Plot of δ18O versus δ15N
Figure 5 Location Map
Figure 6 Historical Aerial Imagery, 1937 Aerial Photo Figure 7 Historical Aerial Imagery, 1955 Aerial Photo Figure 8 Historical Aerial Imagery, June 30, 1985 Landsat
Figure 9 Historical Aerial Imagery, 1997 DOQQ
Figure 10 Historical Aerial Imagery, 2006 DOQQ
Figure 11 Historical Aerial Imagery, 2009 DOQQ Figure 12 Pasture Coincident with Drainages Figure 13 Outline of 1955 Pasture Overlain over the USGS Topographic Map
Figure 14 2006 Aerial Photograph Showing the Stock Pond
Figure 15 Pasture Areas Interpreted from 1955 Imagery
Figure 16 Location of Black Mesa Relative to White Mesa Figure 17 Radar Site at White Mesa near Blanding, Utah, June 21, 1967 Figure 18 Bivouac Site at White Mesa near Blanding, Utah, June 21, 1967
Figure 19 Site Map with DUSA Property Boundary
Figure 20 Natural Nitrate Reservoir: Geoprobe Boring Locations
Figure 21 Nitrate Source Areas: Geoprobe Boring and Core Drilling Locations Figure 22 Stable Isotope Sampling Wells

LIST OF TABLES
Table 1 Project Schedule
Table 2 Laboratory Analytical Parameters by Task and Media

LIST OF APPENDICES
Appendix A Nitrate Extraction and Field Test Procedure
Appendix B Analytical Methods List

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ACRONYMS AND ABBREVIATIONS
bgs below ground surface
CCD counter current decant circuit CFC chlorofluorocarbons
CIR Contaminant Investigation Report
cm/sec centimeters per second
δ delta DEQ Department of Environmental Quality
DRC Utah Division of Radiation Control
DUSA Denison USA
ft/yr feet per year
GPS global positioning system

HASP health and safety plan i average gradient
IAEA International Atomic Energy Agency

k hydraulic conductivity m meter

n porosity
NIST National Institute of Standards and Technology Site White Mesa Mill property
SMOW Standard Mean Ocean Water
SPLP synthetic precipitation leaching procedure
USCS Unified Soil Classification System USGS United States Geological Survey

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1.0 INTRODUCTION
Denison Mines (USA) Corp. (DUSA) and the Co-Executive Secretary of the Utah Water Quality
Board (Co-Executive Secretary) entered into a Stipulated Consent Agreement Docket No.
UGW09-03 dated January 27, 2009 (Consent Agreement) related to nitrate contamination at
DUSA's White Mesa Uranium Mill Site, Blanding Utah (Mill). Pursuant to Item 6.A of the
Consent Agreement, DUSA submitted a Nitrate Contamination Investigation Report, White
Mesa Uranium Mill Site, Blanding Utah, dated December 30, 2009 (CIR) to the Utah Division of
Radiation Control (DRC). By a letter dated October 5, 2010 and hand delivered to DUSA on the
same date, the Co-Executive Secretary notified DUSA of his determination that the CIR is
incomplete (October 5, 2010 DRC Notice). As a result of this determination under Item 7.C of
the Consent Agreement, DUSA is to remedy such omissions in the CIR on or before November
4, 2010.
By an email transmitted to the Co-Executive Secretary on October 20, 2010, and pursuant to
Item 11 of the Consent Agreement, DUSA requested an amendment to the deadline stipulated in
item 7.C of the Consent Agreement, which required that Denison must remedy any omissions in,
content requirements of, or failure to meet any performance standards or objectives relating to
the CIR mandated by Item 6.A of the Consent Agreement, within 30 calendar days of receipt of
the October 5, 2010 DRC Notice (i.e., November 4, 2010). Instead, DUSA requested item 7.C be
amended as follows: a. DUSA representatives would meet with the Co-Executive Secretary and
his legal counsel within two weeks from the date of the email to discuss the legal responsibilities
of DUSA with respect to the nitrate contamination; b. Once the legal responsibilities of DUSA
with respect to the nitrate contamination have been determined, DUSA would, within 30 days
after such a determination was made, submit to the Co-Executive Secretary for approval a plan
and schedule to perform any further investigations that may be required in order to remedy any
such omissions, content requirements or failures of performance standards, and to submit a
revised CIR; and c. DUSA would perform such investigations and submit a revised CIR in
accordance with the agreed upon plan and schedule.
On October 26, 2010, DUSA met with the Co-Executive Secretary, DRC staff and legal counsel
(October 26, 2010 Meeting) to discuss DUSA’s legal obligations with respect to the nitrate
contamination. At the meeting, DUSA reported that it was premature to submit a schedule for
submittal of performance standards and a Corrective Action Plan for the nitrate contamination. In
turn, DUSA presented a new theory for a possible source of the nitrate and chloride
contamination beneath the Mill, based on DUSA’s review of the scientific literature (New
Theory). Based on this New Theory, DUSA suggested that the nitrate contamination source is or
could be caused by naturally occurring nitrate and chloride salt deposits located in the vadose

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zone near or beneath the Mill site area, which have been mobilized by natural and/or artificial
recharge. The parties agreed that this New Theory warranted additional investigation, along with
certain of the other additional studies suggested in the October 5, 2010 DRC Notice. As agreed at
the October 26, 2010 meeting, DUSA submitted via email on November 15, 2010, a letter setting
out the additional studies to be considered that have been identified to date, including the
additional studies suggested in the October 5, 2010 DRC Notice, proposed additional studies
relating to the New Theory, and any other additional studies that DUSA believes may be
relevant. In the November 15, 2010 letter, DUSA proposed that a meeting be held on November
30, 2010 between DRC Staff and DUSA technical and regulatory staff to discuss the foregoing
studies and any associated matters, to agree on the studies to be performed and the manner of
performing those studies, and to develop a plan and schedule for performing such studies and for
submittal of a revised CIR
The meeting contemplated in DUSA’s November 15, 2010 letter was held on November 30,
2010, among DRC Staff and DUSA technical and regulatory staff. At that meeting, DUSA
presented a number of additional studies (herein "Additional Studies") to be performed by
DUSA in order to complete the CIR. The Additional Studies were in addition to the New Theory.
The Co-Executive Secretary and DUSA further agreed that DUSA would prepare a detailed plan
and schedule (the "Plan and Schedule") for performing such studies and for submittal of a
revised CIR that meets the requirements of all applicable regulations on or before February 15,
2011. The February 15, 2011 date for submittal of the Plan and Schedule is somewhat later than
the original 30 days proposed by DUSA in its October 20, 2010 email to the Co-Executive
Secretary, due to the complexity of certain of the Additional Studies to be performed. During the
November 30, 2010 meeting, it was agreed that both the Plan and Schedule and the revised CIR
will be subject to Co-Executive Secretary approval. DUSA’s commitment to prepare and submit
the Plan and Schedule is set out in a Tolling Agreement (the “Tolling Agreement”) dated
December 15, 2010 between DUSA and the Co-Executive Secretary.
This document is the Plan and Schedule, which is being submitted in accordance with the Tolling
Agreement. The purpose of this Plan and Schedule is to define the Additional Studies and to
propose a plan and schedule to complete those studies and submit a revised CIR. DUSA
proposes the Additional Studies described below. A flow chart depicting the logical progression
of additional studies is presented as Figure 1 and a schedule chart showing the expected duration
of each task and subtask is presented as Table1 and is organized by number of months after this
document is approved. The plan and schedule presented here should be considered to be for
Phase 1 of the investigation. Phase 2 would be initiated if Phase 1 encounters items or new
information that requires additional study, such as any additional studies that may be needed to
gain statistical power or to investigate any new findings. The schedule set out in Table 1

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assumes that field work will commence in April 2011 and end in October 2011. This may allow
for some iterations and additional field work if warranted from a review of initial results.
Laboratory results for some of the isotopic analysis may take up to three months to receive, after
the end of the field season. The final mass balance analysis will not commence until all
laboratory data has been obtained. The final report will be prepared after the final mass balance
analysis has been completed.
1.1 Historical Land Use and Geomorphologic Study
A further evaluation of historical land use in the vicinity of the White Mesa Mill property (site)
will be performed in order to supplement the source evaluation (the “Source Review Report”)
that was included in the CIR. This further evaluation is currently under way and will (a) identify
areas that have been subject to agricultural activities and (b) evaluate land-use practices that may
have led to elevated levels of nitrate and other contaminants in groundwater. Objective (a) is
also required to identify areas for sampling of buildup of atmospheric nitrogen, since we seek to
sample areas that have not been subject to anthropomorphic activities. This analysis includes
evaluation of historical aerial photography, historical Landsat satellite imagery, and an Internet-
based search of historic military activities in the region. This study is expected to take up to four
months to complete (Table 1), due to the time required to research and obtain imagery. It is
described in more detail in Section 4.0 of this document.
1.2 Investigation of Potential Natural Nitrate Reservoir
Using the results of the historical land use study, undisturbed alluvial soils on DUSA property at
locations that are close to site operations will be explored with a geoprobe for any potential
natural subsurface reservoir of nitrogen and chloride, as has been described by Wolvaard et al.,
2003) and to provide a background/baseline to the geoprobe study of potential sources identified
in the Source Review Report. The geoprobe portion of this study would start approximately one
month after this document is approved, and is expected to take approximately four months before
laboratory analysis is complete (Table 1). The coring portion of this study will follow the
geoprobing, starting approximately three months after approval of this document and taking four
months until laboratory analysis is complete. The study is described in more detail in Section 5.0
of this document.
If alluvial soils do not yield positive results for nitrate and chloride, coring of the bedrock units
would be performed in order to test the possibility that a reservoir of nitrate and chloride exists at
some level in the bedrock geologic column above groundwater, due to lack of distributed
recharge to groundwater over an extended period of time. If so, keeping a hydraulic head on the
wildlife pond may have mobilized constituents within this reservoir. Note that irrigation of fields

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north of the site or any action that caused new infiltration to groundwater could have had the
same effect. It would be necessary to take core from an area that has not been affected by
focused recharge such as the wildlife ponds or intermittent streams and drainage channels.
Samples of core would be taken at regular intervals, moisture content measured, and leached
with specific amounts of double distilled water to determine the concentrations of nitrate and
chloride present in soil moisture. Mass balance calculations could then integrate the mass of
nitrate and chloride in soil moisture to determine if the total mass is sufficient to account for the
observed concentrations in groundwater. The mass balance may or may not show that the nitrate
in the spiked horizon is enough to account for the nitrate plume.
1.3 Investigation of Potential Nitrate Source Locations
Geoprobe samples will be collected from alluvial soils in or around specific potential sources
identified in the Source Review Report and analyzed by Synthetic Precipitation Leaching
Procedure (“SPLP”) for nitrate and chloride. This work will only be useful in the unconsolidated
soils at the site and would not be able to address the bedrock units. If results of the geoprobe
work indicate the presence of elevated nitrate or chloride in alluvial soils a drill hole will be
advanced through the alluvial material and a rock core of the geologic formation beneath the
alluvium will be drilled, in any of the 15 potential nitrate source locations that are shown to
contain elevated nitrate or chloride in the soil column within the geoprobe soil samples and that
are not active leach fields as identified by DUSA. The geoprobe portion of this study would start
approximately one month after this document is approved, and is expected to take approximately
four months before laboratory analysis is complete (Table 1). The coring portion of this study
will follow the geoprobing, starting approximately three months after approval of this document
and taking four months until laboratory analysis is complete. This study is described in more
detail in Section 6.0 of this document.
1.4 Stable Isotope Study
The stable isotope study is described in detail in Section 7.0 of this document, which contains
specifics on analytes to be sampled and sampling locations. The groundwater sampling portion
of this study would start approximately one month after this document is approved study and is
expected to take approximately seven months before laboratory analysis is complete (Table 1)
due to the non-standard laboratories that are required.
Stable (non-radioactive) isotopes of the same element differ by the number of neutrons in the
atomic nucleus. A variety of physical and biological processes can affect the relative
concentrations of light and heavy isotopes of the same element. This relative enrichment or

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depletion of one stable isotope over another is called isotopic fractionation. During evaporation,
for example, the heavier 18O becomes enriched in the residual water as more of the lighter 16O
enters the vapor phase. Thus, meteoric water, derived largely from the evaporation of ocean
water, is enriched with 16O relative to ocean water.
For another example, nitrate in groundwater that has been denitrified by microbes, or originates
from human or animal waste is enriched with 15N. Measuring the relative proportions of stable
isotopes in water or other media can lead to interpretation of the source or sources for those
isotopes. Figure 2 shows δ15N results from sampling of various sources of nitrate contamination,
including a uranium mill, from McQuillan et al (1989), showing the potential to exclude mill
tailings as a source of nitrate in groundwater, depending on the δ15N signature in the
groundwater. However, Figure 3 shows δ15N results normalized to N2 in the atmosphere from
sampling a different set of sources indicating the complexity that could potentially be
encountered, raising the possibility that, while some sources can be readily distinguishable,
results of any isotopic study could be inconclusive for distinguishing other sources. Finally,
Figure 4 is a plot of δ18O versus δ15N from Roadcap et al (2001), also showing the overlapping
nature of various sources but displaying the additional power of adding δ18O.
A Tritium study to sample groundwater with high nitrate concentrations to confirm whether
groundwater with high nitrate is older or younger than the Mill was considered but rejected as a
duplication of previously collected information. Hurst and Solomon (2008) found that MW-27
and MW-19 showed the influence of young water and commented that the outer margin of the
groundwater mound must be between MW-27 and MW-30 and MW-31 which contain water that
has no tritium and is therefore older than mid-sixties atomic testing (see Figure 22 for the
locations of existing monitoring wells at the site). They state:
“Several samples have tritiogenic helium-3, indicative of young water, however
these are only found in areas influenced by the wildlife ponds (MW-19, and MW-
27). Tritiated water is introduced into the system by recharge from the wildlife
ponds and appears in wells around the wildlife ponds. As recharge water from the
wildlife ponds propagates through the system, evidence of tritiated water will
appear in successive monitoring wells further from the ponds.”
And:
“Furthermore, stable isotope fingerprints of δD and δ18O suggest mixing between
wildlife pond recharge and older groundwater in MW-19 and MW-27. δ34S-SO4
and δ18O-SO4 fingerprints closely relate MW-27 to wildlife pond water, while the
exceptionally low concentration of sulfate in MW-27, the only groundwater site to

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exhibit sulfate levels below 100 mg/L, suggest no leachate from the tailings cells
has reached the well.”
Thus, according to Hurst and Solomon (2008), tritium data from wells in the area of highest
nitrate would contain younger water (the CFC dates for groundwater in MW-27 range from 1963
to 2001). However, they have already proven that groundwater in this area could not have come
from the tailings impoundments.
1.5 Mass Balance Calculations
It is possible to estimate the mass of nitrate and chloride in the groundwater beneath the mill site
by assuming a saturated thickness of groundwater in the aquifer matrix, a porosity of the aquifer
matrix, an average concentration of constituents in groundwater, and an area to which the
average concentration applies. Any potential source of nitrate and chloride will be evaluated to
determine if it has the potential to have caused the mass of nitrate and chloride observed in the
groundwater plume beneath the mill site. First, the potential source must have a means to reach
groundwater such as sufficient water or other fluid to travel through the vadose zone. Second
there must have been sufficient nitrate and chloride in the source to account for the nitrate and
chloride mass observed in the groundwater. Both conditions can be evaluated by mass balance
calculations. This work will support a synthesis of all data collected in previous studies and will
be instituted when all previous work is complete, approximately eight months after approval of
this document (Table 1). This study is described in more detail in Section 8.0 of this document.

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2.0 GEOLOGY AND HYDROGEOLOGY
The Site is located on White Mesa about 6 miles south of Blanding, Utah (Figure 5). Figure 22
shows the locations of existing monitoring wells at the site. The geologic layers beneath the Site
consist of four main units. The surface and shallow alluvium consists of unconsolidated silt and
sand to a depth of approximately 20 feet (22 ft in monitoring well MW-27). The alluvium is
underlain by Cretaceous and Jurassic bedrock as follows, from youngest to oldest: the Upper
Cretaceous Dakota Formation sandstone, siltstone, mudstone and shale, the Lower Cretaceous
Burro Canyon sandstone, mudstone, and claystone, and the Upper Jurassic Brushy Basin
Member of the Morrison Formation mudstone, claystone, shale, and sandstone. The top of the
unconfined water table is located at a depth of 50 to 60 feet below ground surface (bgs) and the
base of the aquifer is at the contact between the base of the Burro Canyon Formation and the top
of the Brushy Basin Member, about 90 feet bgs. Thus the aquifer thickness is about 30 feet, with
an average gradient (i) of about 0.011 from north to south across the Site (14,400 ft from wells
TWN-12 to MW-20, water level elevations from May, 2008). The gradient increases to nearly
0.02 near the wildlife ponds where groundwater mounding occurs. According to Kirby (2008),
the porosity (n) for undifferentiated Dakota and Burro Canyon Formation ranges from 2 to 22
percent, with a mean value of 10 percent. Hydraulic conductivity (K) of the aquifer based on
laboratory measurement had a mean of 0.32 ft/day (1.14 x 10-4 cm/sec). Using the mean K,
mean n, and site groundwater gradient i, the average groundwater velocity across the site is
calculated as follows: V-average = iK/n = 0.035 ft/d x 360 = 13 ft/yr. Thus, based on the
published regional aquifer parameters and local gradient, it would take approximately 1,100
years for water to travel 14,400 ft from wells TWN-12 to MW-20. On-site aquifer testing
indicates a range of groundwater velocities from 0.55 ft/yr to 7 ft/yr in the northeast part of the
site, to 23 ft/yr in the mill area (Hydro Geo Chem, Inc., 2009). Using the higher value of 23
ft/year, it would take approximately 626 years for groundwater to travel from well TWN-12 to
well MW-20.

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3.0 PROJECT MANAGEMENT
This project is managed by Dr. Dan Erskine of INTERA, Inc, Albuquerque, New Mexico. The
field program will be conducted under the direction of Robert Sengebush of INTERA, utilizing
INTERA field staff in cooperation with the DUSA White Mesa mill management and field
personnel. Subcontractors, such as geoprobe operators and drillers, will be under contract to and
under the supervision of INTERA.
3.1 Field Documentation
Field documentation will consist of, but not be limited to, detailed field note books, chain of
custody forms, and digital photographs. In addition, the locations of geoprobe borings and other
field activities will be recorded using a hand held global positioning system (GPS) instrument.
3.2 Health and Safety
An INTERA health and safety plan (HASP) will be prepared to address the health and safety
requirements of all tasks outlined in this work plan. In addition, White Mesa mill health and
safety and radiation protection procedures will be followed. Health and safety tail gate meetings
will be held before starting field work and will address the specific requirements of the tasks
scheduled to be conducted that day. All health and safety protocols and meetings will be under
the supervision of and coordinated with the DUSA White Mesa mill Radiation Safety Officer
and health and safety manager.
The following sections of this work plan describe the specific tasks to be conducted by INTERA
on behalf of DUSA in an effort to identify the source of nitrate in groundwater beneath the site.

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4.0 HISTORICAL LAND USE AND GEOMORPHOLOGIC STUDY
Historic land uses at and in the vicinity of the site were evaluated in the Source Review Report,
which was submitted with the CIR. INTERA Performed a preliminary evaluation of additional
historical land uses in the vicinity of the White Mesa Mill property (site) to (1) identify areas that
have been subject to agricultural activities and (2) evaluate land-use practices that may have led
to elevated levels of nitrate and other contaminants in groundwater. Objective (1) is also
required to identify areas for sampling of buildup of atmospheric nitrogen, since we seek to
sample areas that have not been subject to anthropomorphic activities. For this analysis, we
evaluated historical aerial photography, historical Landsat satellite imagery, and performed a
brief Internet-based search of historic military activities in the region.
Further evaluation using additional imagery and further investigation of military uses of the site
will be ongoing due to discovery during the preliminary evaluation that the mill site had been
previously used as a part of the Pershing Missile Project, Blanding Launch Complex.
4.1 Initial Procedure
INTERA acquired historical aerial photography for the site from 1937, 1955, 1997, 2006, and
2009. We acquired Landsat imagery from 1985. These images are presented in Figures 6
through 11. Outlines of the primary White Mesa Mill features are provided on each image for
reference. Note that the 1985 Landsat image is somewhat blurry due to the fact that Landsat
images pixels are approximately 100 feet (30m) on a side. While the Landsat image does not
provide significant detail, it does provide a useful tool for identifying areas of irrigated
agriculture and riparian vegetation, which show quite clearly as areas that are much greener than
the surrounding landscape.
These specific images were acquired because they were the most readily available and were
available quickly for our analysis. More imagery is available and is being acquired, but will
require some weeks to receive from various archives. However, the imagery that has been
acquired to date allows us to make some preliminary conclusions with respect to historical land
use, and may be supplemented with some additional analyses in the future.
The imagery was analyzed visually primarily for color and texture. Areas of pasture are clearly
visible in the 1937 and 1955 photos as areas of relatively constant color and texture that stand
out from surrounding areas not influenced by anthropomorphic activities. In the 1937 photo, the
pasture areas generally appear as bright white patches. This is a common appearance for
agricultural lands in early photography from the 1930s, because of the high contrast of the
photography. The 1955 photo shows the pasture areas even more clearly, and the quality of the

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photo allows for more detailed analysis. For example, close inspection reveals that the three-
pronged pasture area present in the southwestern corner of Figure 7 is shaped the way that it is
because the linear stretches of pasture are each coincident with a drainage that would be
expected to provide slightly more water to the pasture grass (Figure 12). Figure 12 clearly shows
a set of three drainages, each of which is coincident with a “finger” of pasture. Figure 13 shows
the pasture outline overlain onto the United States Geological Survey (USGS) 7.5-minute
quadrangle topographic map for the area, and the drainages are clearly visible on the map, as is
the stock pond that they empty into in the central portion of the pasture. Figure 14, from 2006,
indicates that the stock pond has been in use continually into recent times.
Using this same logic, and interpreting land use visually based on texture and color primarily
from the 1955 photo (which provides the clearest view, based on present data, of historical
agricultural activity in the vicinity of the site), we identified and digitized obvious pasture areas
(Figure 15).
As discussed above, we also performed a brief Internet-based search of historic military activity
in the vicinity of the site. The Blanding, Utah area was used by the United States Army from
1963 to 1970 as a launch site for Pershing missiles, which were flown to White Sands Missile
Range in New Mexico (Encyclopedia Astronautica, 2011a). Black Mesa (just west of White
Mesa, Figure 16) was one of numerous suborbital launch sites used to test the Pershing and other
missile systems (Encyclopedia Astronautica, 2011b). While some of the historical information
that we have discovered thus far indicates that primary launch operations were on Black Mesa,
other information that we have discovered indicates that support operations such as radar
tracking (Figure 17) and other substantial support activities, even perhaps launches themselves,
occurred at and near the mill site on White Mesa (Figure 18). While these historical photographs
provide only preliminary information, they certainly indicate the strong potential for military
operations on White Mesa that may have led to some or all of the observed present-day
groundwater contamination problems.
4.2 Initial Conclusions and Recommendations
INTERA evaluated historical aerial photography to identify areas that have been used in the past
for grazing or other agricultural activities. These areas were identified for two reasons: (1) to
evaluate areas that may have contributed to nitrate or other contaminants in groundwater due to
agricultural operations and (2) to identify areas that have not been influenced by
anthropomorphic activities during recent historical times, to allow identification of potential
sampling areas for evaluation of natural atmospheric accumulation of nitrates.

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The results from a preliminary analysis of readily-available aerial photography allowed us to
clearly delineate areas in the vicinity of the White Mesa Mill that have been used as pasture in
the past. These areas were digitized and the resulting polygons can be overlain over present-day
aerial photography and mapping data to evaluate them as potential sources of groundwater
contamination as well as identify sampling locations for the atmospheric nitrogen study.
Additional historical aerial imagery is being acquired, and review of this additional information
is being conducted.
With respect to researching historical military operations in the vicinity of the White Mesa Mill,
we have completed a very preliminary search which indicates that the US Army had operations
on White Mesa associated with launch testing of the Pershing missile dating from the early
1960s through about 1970. These activities certainly deserve additional analysis as they have
significant potential to have had soil and groundwater contamination associated with them.
Additional research is underway to more fully evaluate these activities.

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5.0 INVESTIGATION OF NATURALLY OCCURRING NITRATE
RESERVOIR IN SOIL
The purpose of this investigation is to test for the presence or absence of a nitrate and chloride
concentration in the alluvial soil column in selected locations at the Site. The Site and the DUSA
property boundary are shown on Figure 19. Such concentrations or “reservoirs” have been
identified in the scientific literature (Walvoord, et al., 2003, Scanlon, et al., 2005 and others).
“Unsaturated-zone chloride and nitrate profiles archive changes in recharge related to recent
conversion of rangeland to agricultural ecosystems. Increased recharge associated with dryland
as well as irrigated agriculture can lead to degradation of groundwater quality because of
leaching of salts that have been accumulating in the unsaturated zone for thousands of years prior
to cultivation, because of application of fertilizers, and, in irrigated areas, because of evapo-
concentration of applied groundwater. In the SHP (southern high plains), median groundwater
nitrate-N concentrations increased by 221% beneath irrigated areas and 163% beneath dryland
areas, reflecting LU/LC-induced (land use/land cover) contamination of groundwater.” (Scanlon,
et al., 2005).
This investigation will involve geoprobe borings to test nitrate and chloride concentrations in the
alluvial soil, and drilling rock core in several locations.
Based on the results of the historical land use and geomorphologic study, the boring locations
have been chosen to represent areas which have not undergone irrigation or other forms of
culturally-induced surface water recharge. These locations are based on interpretation of aerial
photographic imagery. Actual locations will be selected in the field by the field team leader in
consultation with DUSA management and field personnel. This selection process is designed to
maximize the opportunity of finding soil chemistry that reflects only natural cycles of wetting
and drying from precipitation and evapotranspiration. The presence of such a nitrate and chloride
reservoir would suggest that these concentrations could be present throughout the White Mesa
alluvial soil column and could be mobilized to groundwater as the result of increased surface
water recharge due to irrigation, surface water impoundment, canal leakage, or other recharge
processes.
Scanlon (2005) shows nitrate concentrations in soil on Texas high plains rangeland on the order
of 200 mg/L at depths between approximately 9 and 19 ft bgs, and up to over 300 mg/L in
irrigated high plains soil at approximately 3 ft and a nitrate spike of about 190 mg/L in high
plains dry land farming soil. The thickness of the elevated nitrate mound or spike is on the order
of 6 ft. The non-elevated nitrate and chloride concentrations are on the order of 10 mg/L or less.

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5.1 Geoprobe Nitrate and Chloride Investigation
The purpose of the geoprobe investigation is to determine the presence or absence of a soil
nitrate and/or chloride reservoir in the alluvial soil. The following procedure is written to apply
to both nitrate and chloride, although only nitrate procedures are described from this point
forward. The investigation will consist of 20 selected locations spread across the entire DUSA
mill property. At each location, an initial boring (with no sampling) may be conducted to test
subsurface conditions and one probe boring will be conducted for sample collection. Based on a
log of monitoring well MW-27, the thickness of the alluvial cover near the center of the mill site
is approximately 22 feet. The field team will be prepared to test the entire interval from ground
surface to the top of bedrock or geoprobe refusal (whichever is first) in one foot increments. The
location latitude and longitude of these geoprobe borings will have been recorded prior to
conducting the field work.
The geoprobe boring locations are shown on Figure 20. These locations are approximate and
may be changed based on judgment of the field team leader in consultation with DUSA
personnel. The actual “as built” location of each boring will be recorded in the field with a hand
held GPS instrument.
The geoprobe boring naming protocol is as follows:
GP-XX, where GP stands for geoprobe and XX is the number of the location, as 01, 02, 12, etc.
The geoprobe boring locations will be recorded in the field note book as follows:
Boring ID Latitude Longitude
The geoprobe boring samples will be collected using the following methods:
1. Set up the geoprobe in the pre-selected location using a map and GPS. Create a labeled
GPS waypoint for the “as built” location.
2. Concurrent with the setup of the geoprobe location, collect a non-geoprobe soil sample
from 0.5 ft bgs and test for nitrate and chloride according to the field test procedures
described below. The total sample volume should fill a one quart sealable plastic bag.
This is the “background” or “baseline” sample for this location. This sample will be
designated as GP-XX-BKG.
3. Probe to refusal to determine subsurface soil conditions and the depth to the top of
bedrock (Dakota Formation or Burro Canyon Formation). This is a non-sampling
geoprobe boring and is optional, at the discretion of the field team leader.

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4. Probe and obtain a continuous soil core from surface to total depth in one geoprobe
boring.
5. Measure and mark depth in 1 foot increments on the boring core sleeve. This is adequate
sampling interval resolution to identify elevated nitrate or chloride concentrations on the
order of 6 ft thick (Scanlon, 2005).
6. Open the sleeve to observe and describe the alluvial texture and/or lithology. Describe or
log the soil texture based on the Unified Soil Classification System (USCS).
7. Place the soil from each one-foot increment into a sealable plastic bag. Mix the soil
thoroughly in the plastic bag by gently inverting the bag multiple times. The purpose of
this procedure is to thoroughly blend the soil so that a sample aliquot from the bag will be
representative of the entire one-foot interval. Seal the plastic bag, label and store for
additional analysis in the event the interval contains elevated nitrate and/or chloride.
8. Select a sample aliquot from the bag and test for nitrate using the nitrate field test kit test
strips. This entails mixing a volume of soil with a volume of double distilled water
(prepared by the laboratory) to create a liquid extract. Test the liquid extract with the
nitrate test strip. Follow the test strip manufacturer’s and USDA Natural Resource
Conservation Service instructions, attached to this work plan, Appendix A. Note that the
test strip range is 0-50 mg/L. If the test strip reads 50 mg/L, perform a dilution to
determine the actual concentration, according to instructions in Appendix A. The chloride
test strip range is 30-600 mg/L.
9. Record the test results in the field notebook.
10. If any of the soil column analyses indicate the presence of elevated nitrate, select the
balance of that interval sample and place in a second, labeled sealable plastic bag (double
bag) for delivery to the analytical laboratory for analysis of nitrate and chloride by
synthetic precipitation leaching procedure (SPLP) method. “Elevated” concentrations are
defined as those 1 foot intervals with nitrate concentrations at least twice the average
background concentration, based on field analysis of a sample 0.5 ft below ground
surface. Analytical methods for aqueous leachate analysis are listed in Appendix B.
Handle, package, label, fill out chain-or-custody, and deliver the samples according to the
soil sampling and handling procedures.
11. Collect a sample from the bottom of the boring, regardless of whether it tests positive for
nitrate, and package in a double bag for delivery to the laboratory and analysis for nitrate
and chloride by the SPLP. Also collect one sample for SPLP from an interval which lacks
evidence of elevated nitrate, as a baseline analysis.

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12. Discard the remaining bagged soil on the location and dispose of the plastic bags.
13. Fill the boring with dry bentonite material to seal the boring and restore surface location.
14. Move to the next location.
15. For the purpose of cost estimation, assume 15 test kit analyses per boring and four (4)
SPLP analyses for nitrate and chloride per sampling location.
16. The core hole borings will be back filled with cement/bentonite grout after drilling. The
location of actual boring location will be recorded with a hand-held GPS instrument for
plotting on the map and for future reference.
17. Assess results with management.
5.2 Coring Study to Explore for Natural Nitrate Reservoir
This task consists of advancing a drill hole through the alluvial material and then drilling a rock
core of the formation beneath the alluvium, in up to four potential nitrate reservoir locations that
are shown to contain elevated nitrate in the soil column within the geoprobe soil samples. The
definition of “elevated” is a nitrate concentration at least twice background, based on the
concentration of nitrate in near-surface soil samples, as described in Section 5.1. The purpose of
this work is to trace the nitrate from the base of the alluvium and into the bedrock column
(Dakota Formation and upper Burro Canyon Formation) to the water table.
The coring will be conducted with a conventional truck-mounted drill rig using a combination of
hollow stem auger and air rotary methods, without introducing water or other drilling fluids into
the borehole.
Using monitoring well MW-31 as an example, the subsurface layers are expected as follows:
Alluvium: 0-22ft bgs (top of bedrock – 22 ft bgs)
Depth to Groundwater (2009, approximate): 77 ft bgs
Length from top of bedrock to groundwater: 77 – 22 = 55 ft
Therefore, the length of core drilling in this example is 55 ft.
The entire core interval will be boxed and logged (described) according to standard geologic
methods.
Three one foot core intervals will be collected from the interval between the base of the alluvium
and the groundwater table, including the core located at the top of the water table. The three

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cores will be evenly spaced within the distance between the alluvium and the water table. For
example, if the top of bedrock is 22 ft bgs, the water table is at 77 ft bgs, and the interval from
the top of bedrock to the water table is 55 ft, the three cores will be as follows: the top core (from
22 – 23 ft), the middle core (22 + 27 ft = 49 -50 ft) and the bottom core (49 + 27 = 76-77 ft,
approximately).
No field testing will be conducted on these rock cores. The one-foot core intervals will be
packaged and shipped to a State of Utah certified analytical laboratory for analysis of the
presence of nitrate and chloride in the rock cores by the SPLP analysis method. The laboratory
will need to crush, pulverize, and blend the rock core material, and measure the pore moisture,
before conducting the analysis. Each analysis will be considered representative of the entire one
foot interval.
The core hole borings will be backfilled with bentonite grout after drilling. The as-built boring
locations will be recorded with a hand-held GPS instrument for plotting on the site map and for
future reference in the field.

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6.0 INVESTIGATION OF POTENTIAL NITRATE SOURCE LOCATIONS
This investigation combines an initial geoprobe investigation of potential nitrate and chloride
sources, followed by bedrock coring if positive results for nitrate and chloride are encountered
during geoprobing.
6.1 Geoprobe Investigation of Potential Nitrate Source Locations
The purpose of this investigation of potential nitrate and chloride source locations is to assess the
presence or absence of elevated nitrate and chloride concentrations in the alluvial layer (above
bedrock) in locations where past or ongoing activities may have contributed nitrate and/or
chloride to the soil and/or groundwater. Specifically, the purpose is to test whether nitrate and
chloride residues can be found in alluvial soils or at the alluvial bedrock interface. The alluvial
bedrock interface marks a change in porosity and permeability and is judged to be the most likely
location to find nitrate and chloride residues from potential sources that found a pathway to
groundwater.
The potential nitrate source locations include up to seven (7) leach fields, as well as other
installations such as ammonia tanks, a sewage vault, and Lawzy Lake, a former pond that may
have held contaminated water. The investigation of these potential sources is contingent on
access with the geoprobe rig and subject to approval by DUSA management, based primarily on
field team health and safety considerations. The subsurface configuration or design of the leach
fields, including the potential for underground piping, is not known. Any excavation or borings
in these leach fields will require prior identification of underground structures, such as piping,
septic tanks, or vaults, using techniques such as air knife or equivalent “daylighting” methods.
Design drawings and records will be reviewed prior to work and the borings will only be
attempted with the full approval of DUSA management.
The leach field locations and dates of operation listed below are provided by DUSA management
and are shown on Figure 21:
Potential Nitrate Source Locations
1. Main leach field (also known as Leach Field east of Scalehouse, 1985 to present)
2. Sewage vault/lift station
3. Scale house leach field, (also known as Leach Field south of Scalehouse, 1977-1979)
4. Former office leach field
5. Ammonia tanks

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6. SAG leach field (Leach Field north of mill building, 1998 to 2009)
7. Cell 1 leach field (Leach Field east of Cell #1, up to 1985)
8. Fly ash pond
9. Chlorate tanks
10. Ammonium sulfate crystal tanks
11. Lawzy sump
12. Lawzy Lake
13. Former vault/lift station (to Former Office Leach Field) (1992 to 2009)
14. Truck shop leach field (1979-1985)
15. Counter Current Decant/Solvent Extraction (CCD/SX) leach field
Note that locations 1 and 15 are known to be in use at present. For these locations, optional
source influent sampling and analysis may be conducted instead of subsurface soil sampling and
field testing. Conducting borings in the active leach fields is not recommended due to the
potential to create a pathway for the waste water fluids from the leach field down to the
groundwater table. As an alternative, water samples will be collected from influent piping (if
possible) near the operating leach field, downstream of the septic tank (if present) that is
designed to collect solids. It is not known at this time if such influent piping will be accessible.
These waste water influent samples, if any, will be analyzed for nitrate and chloride by the
methods shown in Table 2 of this work plan. Sampling and analysis of raw wastewater influent is
described in detail in the publication, “Influent Constituent Characteristics of the Modern Waste
Stream from Single Sources.” (Lowe, et al., 2009). As a point of reference, the average
concentration of nitrate in raw waste water from single sources is 2.1 mg/L (Lowe, et al., 2009).
If waste water is sampled, it will be analyzed for nitrate and chloride and a mass balance
calculation will be performed to determine if the influent source could create the level of nitrate
concentrations found currently in groundwater beneath the site.
The following tasks will be conducted on the locations listed above (except for the two leach
fields known to be currently in use):
1. If approved by DUSA management, conduct test geoprobe boring (without core sleeve)
to refusal to determine alluvial thickness and evaluate subsurface conditions. If
subsurface conditions are deemed safe for boring and sampling, proceed as described
below.

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2. Conduct geoprobe boring with core sleeve to collect soil core through alluvial interval.
3. Collect 6-inch core sample from two intervals within the alluvial interval and one 6-inch
core sample from the base of the alluvial interval, at the contact with the bedrock
formation.
4. Place the soil material in double, sealable plastic bags and label.
5. Collect an aliquot of the material and test with the nitrate field test kit according to the
procedures described in Appendix A.
6. For samples with positive results from the field test kit analysis, handle, pack, and ship to
the laboratory, with chain-of-custody, per standard operating procedures.
7. Backfill the geoprobe boring with bentonite to seal the hole.
8. Thoroughly clean the geoprobe drill pipe and other equipment between locations.
9. Analyze for the following, in soil:
a. Nitrate
b. Chloride
6.2 Coring Study in Potential Nitrate Source Locations
This task consists of advancing a drill hole through the alluvial material and then drilling a rock
core of the geologic formation beneath the alluvium, in up to 13 potential nitrate source locations
that are shown to contain elevated nitrate in the soil column within the geoprobe soil samples.
These 13 locations are the locations which have been identified as possible nitrate source areas
but are not the locations of the two active leach fields at locations 1 and 6. The procedures for
conducting this core drilling and sampling are identical to those described in Section 5.2.

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7.0 STABLE ISOTOPES STUDY
The purpose of the stable isotope study is to identify the source of the nitrate in the groundwater
beneath the site.
Stable (non-radioactive) isotopes are elements that have the same name (i.e. oxygen, nitrogen,
carbon, etc.) but differ by the number of neutrons in the atomic nucleus. Physical and biological
processes can affect the relative concentrations of light and heavy isotopes of the same element.
This relative enrichment or depletion of one stable isotope over another is called isotopic
fractionation. During evaporation of water, for example, the heavier 18O becomes enriched in the
residual water as more of the lighter 16O enters the vapor phase. Thus, meteoric water, derived
largely from the evaporation of ocean water, is enriched in 16O relative to ocean water.
Biological organisms preferentially use 14N, rather than 15N, for respiration and assimilation
because the chemical bonds of lighter isotopes are generally broken more easily than those of
heavier isotopes. 14N becomes concentrated in cell mass while 15N becomes concentrated in the
residual nitrogen source and in human and animal wastes. In addition, a disproportionate amount
of 14N as compared to 15N is released to the atmosphere during ammonia volatilization from
human and animal waste, fostering enrichment of 15N. Thus, nitrate in groundwater that has been
denitrified by microbes, or originates from human and animal waste, is enriched with 15N. These
isotope fractionations have long been studied to trace flow paths and mixing of water sources,
and to identify sources of nitrate and ammonia in groundwater. Isotopic compositions are usually
presented as delta values (e.g., δ15N), which express the ratio of the heavy to light isotopes (i.e.,
2H/1H, 15N/14N, and 18O/16O), relative to a universal standard.
Figure 2 shows δ15N results from sampling of various sources of nitrate contamination, including
a uranium mill, from McQuillan et al (1989), showing the potential to exclude mill tailings as a
source of nitrate in groundwater, depending on the δ15N signature in the groundwater.
However, Figure 3 shows δ15N results normalized to N2 in the atmosphere from sampling a
different set of sources indicating the complexity that could potentially be encountered, raising
the possibility that, while some sources can be readily distinguishable, results of any isotopic
study could be inconclusive for distinguishing other sources.
Finally, Figure 4 is a plot of δ18O versus δ15N from Roadcap et al (2001), also showing the
overlapping nature of various sources but displaying the additional power of adding δ18O. Hurst
and Solomon (2008) used Deuterium and δ18O values to fingerprint groundwater sources during
their study at White Mesa and it was part of their evidence that young water in MW-27 and MW-

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19 was coming from the wildlife ponds (see Figure 22 for the locations of existing monitoring
wells at the site).
The possible nitrate sources at the site include nitrate in waste water (in leach fields), nitrate-
fertilizer, ammonium nitrate and other nitrate-producing compounds from historical missile
launch activity, and/or a naturally occurring nitrate reservoir in soil. The only potential pathway
on the site from the surface to groundwater that is known at this time is the surface water in the
wildlife ponds and some other nearby stockponds. Other sources could include historic stock
ponds, possible deep disposal wells operated by historic users of the site, leach fields or other
installations where continuous head and soil moisture is created from the surface to groundwater
and a demonstrated connection between surface water and groundwater on the site could point to
a possible connection between a nitrate/chloride source in that surface water and the current
elevated nitrate and chloride concentrations in groundwater.
Previous sampling and analysis for stable isotopes in groundwater was conducted by the
Department of Geology and Geophysics, University of Utah, and documented in the report
“Summary of work completed, data results, interpretations and recommendations for the July,
2007 Sampling Event at Denison Mines, USA, White Mesa Uranium Mill Near Blanding, Utah
(Hurst, G.T., and Solomon, D.K., 2008) prepared on behalf of the Utah Division of Radiation
Control (DRC). The stable isotopes measured for the DRC study were tritium, tritogenic helium-
3, deuterium, 18O, 15N, and 34S.
The DRC report concludes the following: “δ34S and δ18O isotopic signatures on dissolved sulfate
provide distinction between surface water sites and monitoring wells. The tailings cells and
wildlife ponds exhibit significantly enriched δ18O-SO4 values relative to monitoring wells, and
depleted δ34S-SO4values relative to monitoring wells. MW-27 (see Figure 22) is the only
monitoring well to bear an isotopic fingerprint closely related to that of the surface water sites,
suggesting recharge from the wildlife ponds has reached MW-27 and further evidence that the
wildlife ponds are providing recharge to the aquifer. Sites with high concentrations of metals
(MW-3, MW-14 shallow and deep, MW-15, MW-18, and MW-22) bear very different isotopic
fingerprints than those of the surface water sites. In general, the data collected in this study do
not provide evidence that tailings cell leakage is leading to contamination of groundwater in the
area around the White Mesa mill. Evidence of old water in the majority of wells, and
significantly different isotopic fingerprints between wells with the highest concentrations of trace
metals and surface water sites, supports this conclusion. The only evidence linking surface
waters to recharging groundwater is seen in MW-27 and MW-19. Measurable tritium and CFC
concentrations indicate relative young water, with low concentrations of selenium, manganese,
and uranium. Furthermore, stable isotope fingerprints of δD and δ18O suggest mixing between

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wildlife pond recharge and older groundwater in MW-19 (north of northern wildlife pond) and
MW-27 (west of southern wildlife pond, at NE corner of tailings cell no. 1). δ34S-SO4 and δ18O-
SO4 fingerprints closely relate MW-27 to wildlife pond water, while the exceptionally low
concentration of sulfate in MW-27, the only groundwater site to exhibit sulfate levels below 100
mg/L, suggest no leachate from the tailings cells has reached the well.” (Hurst and Solomon,
2008, p. 59). “The southern margin of artificial recharge is likely to be between MW-27 and
MW-31 while the northern margin appears to be between MW-18 and MW-19.” (Hurst and
Solomon, 2008, p. 27).The Hurst and Solomon study documents that the tailings cells are not
discharging to groundwater and thus, the tailings cell fluids are not the nitrate source.
By established convention, isotopic ratios are defined as delta (δ) values, which are obtained by
the equation:
δ (isotope) = {[R(sample) – R(standard)]/R(standard)} –1 (1,000).
Where: δ (isotope) = values in per thousand (‰) or per mil and R(sample) = the ratio of the first
and second isotope such as 18O/16O, and R(standard) = the ratio of 18O/16O used in international
or other standards. For example, the standard for 18O/16O is Standard Mean Ocean Water
(SMOW). A positive (+) δ value indicates that the heavier isotope (i.e., 18O) in the sample is
enriched when compared to the standard. A negative (–) value indicates that the sample has more
of the lighter (16O) isotope. The International Atomic Energy Agency (IAEA) and the National
Institute of Standards and Technology (NIST) have established and published these standards.
The wells to sample for stable isotopes in groundwater are as follows and are shown on Figure 22:
• MW-20
• MW-31
• TWN-19
• TWN-2
• TWN-9
• TWN-17
If a source of nitrate is discovered during either the investigation of naturally occurring nitrate
reservoir in soils or in the investigation of potential nitrate source locations, samples from that
source will also be sent for analysis. In addition, a sample of solution from the slimes drain of
tailings Cell 2 will be collected and sent for analysis.

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The proposed stable isotope and other analyses for the groundwater, leachate, and tailings
solution samples are as follows:
• nitrate + nitrite
• total Kjeldal nitrogen
• chloride
• δ15Nnitrate and δ18Onitrate
• δ18Owater and δDwater (D = 2H, Deuterium)
The stable isotope groundwater samples will be collected during the regularly scheduled
quarterly groundwater sampling event conducted by the Site water sampling team.
7.1 Quality Assurance and Quality Control Procedures
The groundwater sampling and analysis procedures are described in the DUSA Quality
Assurance Project Plan (QAP) and on Table 2 of this Work Plan. A commercial laboratory has
been identified that maintains an internal quality assurance program and is able to do all the
stable isotope analyses that are required. Isotech Laboratories, Inc. in Champaign Illinois states
that:
“At least 20% of all analyses at Isotech are for quality assurance and quality control
(QAQC). In addition to regularly calibrating all instruments with standard materials
traceable to the National Institute of Standards and Testing (NIST), or the International
Atomic Energy Agency (IAEA), approximately 10% of the analyses are of internal check
standards that have compositions similar to those of the samples being analyzed. For
example, when analyzing methane in samples that are mostly air, we test our methods and
our equipment using standards that are diluted with air, and not with pure gases. An
additional 10% of all analyses are duplicates of the customer’s samples.”
Isotech will be required to submit all quality assurance back up data with its final data package
submission. In addition to Isotech’s internal quality assurance, the following field-generated QC
samples will be provided: two blind duplicate samples of groundwater, one blind duplicate of
any leachate, and one blind duplicate of slimes drain solution will be sent to Isotech for analysis.
Sufficient amounts of all samples will be collected such that a split sample can be archived
should any reanalysis be required. Any duplicate sample that returns results such that the isotope
ratios differ by more than 20% will require reanalysis of all samples. Results of reanalysis will
be statistically analyzed to determine error bars around each data point.

Work Plan for Supplemental Contaminant Investigation Report
for White Mesa Mill Nitrate Investigation 24 February 18, 2011
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8.0 MASS BALANCE CALCULATIONS
It is possible to estimate the mass of nitrate and chloride in the groundwater beneath the mill site
by assuming a saturated thickness of groundwater in the aquifer matrix, a porosity of the aquifer
matrix, an average concentration of constituents in groundwater, and an area to which the
average concentration applies. Any potential source of nitrate and chloride will be evaluated to
determine if it has the potential to have caused the mass of nitrate and chloride observed in the
groundwater plume beneath the mill site. First, the potential source must have a means to reach
groundwater such as sufficient water or other fluid to travel through the vadose zone. Second
there must have been sufficient nitrate and chloride in the source to account for the nitrate and
chloride mass observed in the groundwater. Both conditions can be evaluated by mass balance
calculations.
An example of these mass balance calculations was presented in the December 30, 2009 CIR
where one of the suggested possibilities was a groundwater mound from the tailings cells that
might cause elevated nitrate and chloride concentrations upgradient in the area of the nitrate and
chloride plume. A calculation for nitrate to evaluate this possibility (a calculation for chloride
would be similar) suggests that on the order of eleven percent tailings solution (assuming the
highest recently observed nitrate concentration in the tailings of 290 mg/L) would have to mix
with unimpacted groundwater (assuming 1 mg/L) in order to account for the observed mass of
nitrate in groundwater, assuming an average nitrate concentration in the plume above the 20
mg/L isopleth of 30 mg/L.
The size of the nitrate plume above 20 mg/L is approximately 40 acres, or 1,800,000 square feet
in map area. Assuming 45 feet of saturation (Chloroform Investigation Report) and a porosity of
0.2, there are 16,200,000 cubic feet or 121,176,000 gallons of groundwater in that area. Eleven
percent of that is 13,329,360 gallons (approximately 41 acre feet) which is a conservative
estimate of the volume of tailings solution that would have to be mixed with groundwater to
account for the mass of nitrate in the portion of the plume above 20 mg/L nitrate.
Assume:
• Nitrate Concentration in Tailings Solution 290 mg/L
• Nitrate Concentration in un-impacted Groundwater 1 mg/L
• Average Plume Concentration 30 mg/L
Mixing Equation: Ct*Vt + Cg*Vg = Cm*Vm (eq 1)

Work Plan for Supplemental Contaminant Investigation Report
for White Mesa Mill Nitrate Investigation 25 February 18, 2011
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Where: Ct = Concentration of nitrate in tailings solutions
Vt = Volume of tailings solutions
Cg = Concentration of nitrate in unimpacted groundwater
Vg = Volume of unimpacted groundwater
Cm = Concentration of nitrate in mixture of groundwater and tailings solutions
Vm = Volume of mixture of groundwater and tailings solutions
Another Equation: Vt + Vg = Vm (eq 2)
Substituting eq2 in eq1: Ct*Vt + Cg*Vg = Cm* (Vt + Vg) (eq 3)
Substitute Nitrate Concentrations in eq3
290*Vt + 1*Vg = 30*(Vt + Vg)
290*Vt + 1*Vg = 30*Vt + 30*Vg
260*Vt = 29*Vg
Vt = 29/260*Vg = 0.11*Vg
The volume of tailings solution would have to be eleven percent of the volume of un-impacted
groundwater in the mixture.
That amount of seepage from the tailings cells would certainly generate a groundwater mound.
Such a mound would have to be on the order of 5 feet on average over the entire 40 acres, but
would likely be much higher than that at the centroid of the plume and would taper off toward
the edges of the plume. However, no such mounding exists under the tailings cells. While
groundwater mounding can be observed towards the eastern portion of the site, away from the
tailings cells, it is clearly related to the wildlife ponds and not the tailings cells. As a final point,
if the concentration of nitrate in tailings documented in the Statement of Basis (24 mg/L) were
used in the calculation, no amount of tailings solution would bring the plume concentration to 30
mg/L.

Work Plan for Supplemental Contaminant Investigation Report
for White Mesa Mill Nitrate Investigation 26 February 18, 2011
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9.0 REFERENCES
Encyclopedia Astronautica. 2011. http://www.astronautix.com/sites/blakmesa.htm.
Hurst, G.T., and D.K. Solomon. 2008. Hurst and Solomon, 2008, Summary of work completed,
data results, interpretations and recommendations for the July, 2007 Sampling Event at
Denison Mines, USA, White Mesa Uranium Mill Near Blanding, Utah.
Hydro Geo Chem, Inc. 2009. Site Hydrogeology and Estimation of Groundwater Pore Velocities in the Perched Zone White Mesa Uranium Mill Site Near Blanding, Utah
INTERA, Inc. 2009. Nitrate Concentration Investigation Report, White Mesa Mill Site,
Blanding, Utah.
Kirby, Stephen. 2008. Geologic and Hydrologic Characterization of the Dakota-Burro Canyon
Aquifer Near Blanding, San Juan County, Utah, Special Study 123, Utah Geological Survey.
Lowe, Kathryn S., Maria B. Tucholke, Jill M. B. Tomaras, Kathleen Conn, Christiane Hoppe,
Jorg E. Drewes, John E. McCray, and Junko MunaKata-Marr. 2009. Influent Constituent
Characteristics of the Modern Waste Stream from Single Sources. Colorado School of
Mines, Environmental Science and Engineering Division, Golden, CO.
McQuillan, D.M., M.J. Jasper, and B.H. Swanson. 1989. Ground-water contamination by septic-tank use: A field study in the Albuquerque South Valley-West Mesa region, Bernalillo
County, N.M. NMED Open-File Report EID/GWB-89/2, 37 p.
Roadcap, George S., Keith C. Hackley, Hue-Hwa Hwang, Thomas M. Johnson. 2001.
“Application of Nitrogen and Oxygen Isotopes to Identify Sources of Nitrates.” Illinois Groundwater Consortium Conference, web publication, www.siu.edu/worda/igc/proceedings/01/roadcap.pdf.
Scanlon, B.R., R.C. Reedy, D.A. Stonestrom, D.E. Prudic, and K.F. Dennehy. 2005. “Impact of
land use and land cover change on groundwater recharge and quality in the southwestern
US,” in Global Change Biology, v. 11, 1577-1593.
U.S. Department of Agriculture (USDA). 2001. Soil Quality Test Kit Guide, Natural Resources Conservation Service, Soil Quality Institute, July.
Walvoord, M.A., F.M. Phillips, D.A. Stonestrom, R.D. Evans, P.C. Hartsough, B.D. Newman,
and R.G. Striegl. 2003. “A Reservoir of Nitrate Beneath Desert Soils,” in Science, v. 302,
1021-1024.

Figures

Nitrate and Chloride Investigation
Land Use and
Geomorphic
Evaluation
Background
Geoprobe Soil Reservoir?
Yes
Initial Mass
Balance
Viable
Explanation?
Yes
Soil Reservoir?
No
4 Deep
Core HolesSoil Reservoir?
No
Detailed Study to
Gain Statistical
Power
Geoprobe
Potential
Sources
Above
Background?
No
Above
Background?
Yes
Core to
Groundwater
Evidence of
Transport to
Groundwater?
No
No Source
Identified
Evidence of
Transport to
Groundwater?
Yes
Source
Identified
Stable Isotope
Fingerprinting
Source
Fingerprinting
Groundwater
Fingerprinting
Final Mass
Balance
Saturday, February 12, 2011
Process Flow for the Supplemental Contaminant Investigation, White Mesa Mill Site, San Juan
County, Utah
Viable
Explanation?
No

Figure 2. δ15N results from sampling of various sources of nitrate contamination

Figure 3. δ15N results normalized to N2 in the atmosphere from sampling a wider range of sources

Figure 4. A plot of δ18O versus δ15N

S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2011_WP_Nitrate_Response\20110121ReginalMap.mxd
Figure 5Location MapNitrate and ChlorideSource InvestigationSource(s):
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure1_1937Aerial.mxd 12/28/2010
Figure 6Historical Aerial Imagery1937 Aerial Photo¨
1,500 0 1,500750
Feet
Source(s): Aerial – Earth Data Analysis Center, New Mexico.
Legend
Site Feature
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure2_1955Aerial.mxd 01/10/2011
Figure 7Historical Aerial Imagery1955 Aerial Photo¨
1,500 0 1,500750
Feet
Source(s): Aerial – Earth Data Analysis Center, New Mexico.
Legend
Historical Clearing (From 1955 Imagery)
Site Feature
This edge represents the outline for T37S R22E, Section 28, NE, NW (Quarter-Quarter) Boundary
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure3_1985Aerial.mxd 12/28/2010
Figure 8Historical Aerial ImageryJune 30, 1985 Landsat ¨
1,500 0 1,500750
Feet
Source(s): Landsat from GLOVIS, U.S. Geological Survey
Legend
Site Feature
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure4_1997Aerial.mxd 12/28/2010
Figure 9Historical Aerial Imagery1997 DOQQ¨
1,500 0 1,500750
Feet
Source(s): 1997 7.5-Minute DOQQ County Mosaic, U.S. Geological Survey
Legend
Site Feature
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure5_2006Aerial.mxd 12/28/2010
Figure 10Historical Aerial Imagery2006 DOQQ¨
1,500 0 1,500750
Feet
Source(s): 2006 7.5-Minute DOQQ County Mosaic, U.S. Geological Survey
Legend
Site Feature
Cell No. 3
Cell No. 2
Mill SiteCell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\Figure6_2009Aerial.mxd 12/29/2010
Figure 11Historical Aerial Imagery2009 DOQQ¨
1,500 0 1,500750
Feet
Source(s): 2009 7.5-Minute DOQQ County Mosaic, U.S. Geological Survey
Legend
Site Feature

Figure 12. From the 1955 Photo Showing Pasture is Coincident with Drainages, which are Wetter
than the Surrounding Area (A stock pond is visible near the center of the pasture area [yellow arrow]).

Figure 13. Outline of 1955 Pasture Overlain over the USGS Topographic Map Showing Drainages and a Stock Pond (Yellow Arrow) in the Central Portion of the Pasture

Figure 14. 2006 Aerial Photograph Showing the Stock Pond

Cell No. 3
Cell No. 2
Mill Site
Cell No. 1
Cell No. 4A
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2010_AerialImageryResearch\HistoricalAerialResearch_CP.mxd 01/10/2011
Figure 15Pasture Areas Interpreted
from 1955 Imagery¨
1,500 0 1,500750
Feet
Source(s): Aerial – Utah GIS Portal website
Legend
Historical_Clearings
Site Feature

Figure 16. Location of Black Mesa relative to White Mesa

Figure 17. Radar Site at White Mesa near Blanding, Utah, June 21, 1967 (J. Willard Marriott Library, University of Utah, 2011)

Figure 18. Bivouac Site at White Mesa near Blanding, Utah, June 21, 1967 (J. Willard Marriott
Library, University of Utah, 2011)

191
ENTRANCE SPRING
CORRAL SPRING
RUIN SPRINGS
COTTONWOOD SEEP
WESTWATER SEEP
CORAL CANYON SEEP
0.5 0 0.50.25 Miles
Source(s): Utah GIS Portal website
Legend
DUSA Property Boundary
Monitoring WellPiezometerRegional WellSpring/Seep
Surface WaterChloroform Monitoring WellNitrate Monitoring Well
Windmill
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2011_WP_Nitrate_Response\20110124SiteMap.mxd
Figure 19Site Map with DUSAProperty BoundaryNitrate and ChlorideSource Investigation
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
!(
")
")
Cell No. 1 Mill Site
Cell No. 2
Cell No. 3
Cell No. 4A
5
16
15
14
6
18
17
7
19
8
20
13
12
4
2
3
11
1
10
9
Cell No. 4B
¨1,500 0 1,500750
Feet
Source(s): Utah GIS Portal website, dated 2009; U.S. Geological Survey
Legend
!(Geoprobe Boring Location
Pershing Missle Staging Area
DUSA Property Boundary
Historical Disturbance (From 2009 Imagery)
Historical Disturbance (From 2006 Imagery)
Historical Disturbance (From 1997 Imagery)
Historical Disturbance (From 1984 Imagery)
Historical Disturbance (From 1973 Imagery)
Historical Disturbance (From 1955 Imagery)
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2011_WP_Nitrate_Response\20110217Geoprobes.mxd
Figure 20Natural Nitrate Reservoir:Geoprobe Boring LocationsSupplemental ContainmentInvestigation
Frog Pond
Location of "Channel"
White Mesa Radar
Location of Barbed Wireand Bullet Casings
MW-18
PIEZ-1
MW-19
PIEZ-2
MW-27
TW4-21
PIEZ-3
TW4-22
TW4-20
TW4-19 TW4-18
TW4-5
TW4-25
TW4-24
TW4-9
TW4-12
TW4-13
TW4-2
TW4-8
TW4-1
MW-04
TW4-11TW4-16
MW-26
MW-32
MW-31
TW4-10 TW4-3
Cell No. 1
Cell No. 2
WildlifePond
TW4-7
TWN-8
TWN-5
TWN-7
TWN-18
TWN-3
TWN-2 TWN-4
TWN-1

Frog Pond approx. 1 mile NEWastewater Treatment Plant approx. 2 miles NE
Pipeline
Pipe
l
i
n
e
Law
z
y

P
i
p
e
l
i
n
e
L
a
w
z
y

P
i
p
e
l
i
n
e
Underground Sew
e
r
l
i
n
e
Cell 1 Leach Field [7]
CCD
V205 Oxidation Tanks
Fly Ash Pond [8]
Chem Lab
Met Lab
Former OfficeLeach Field [4]
Sewage Vault [2]
Scale House Leach Field [3]1977-1979
Main Leach Field [1]1985-Present
Ammonium SulfateCrystal Tanks [10]
Ammonia Tanks [5]
V205 Mini Lab & V205 Precip
YC Precip Mini Lab
SAG Leach Field [6]1998-2009
Lawzy Sump [11]
Wildlife Pond
SX Mini Lab
Former Vault [13] 1992-2009
Lawzy Lake [12]
Truck Shop1979-1985Leach Field [14]
Chlorate Tanks [9]
New CCD/SXLeach Field [15]2009-Present
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2011_WP_Nitrate_Response\20110121BoringsCoreDrilling.mxd
Figure 21Nitrate Source Areas:Geoprobe Boring andCore Drilling LocationsNitrate and ChlorideSource Investigation
300 0 300150Feet
Source(s): Aerial – Utah GIS Portal website, dated 2009;Wells – HGC, Inc., May 2008 report.
Legend
Pipeline
Potential Nitrate and Chloride Sources
Leach Field (currently in operation)Leach Field – Geoprobe Boringand Core Drilling Location
Monitoring Well
Piezometer
Spring/Seep
Surface Water
Chloroform Monitoring Well
Nitrate Monitoring Well
MW-01
MW-18 PIEZ-1
MW-19
PIEZ-2
MW-27
TW4-21 PIEZ-3
TW4-22
TW4-20
TW4-19 TW4-18TW4-5
TW4-25
TW4-24
TW4-9 TW4-12
TW4-13TW4-2
TW4-8TW4-1
MW-04
TW4-11TW4-16
MW-26
MW-32MW-31
MW-30
MW-28 TW4-10 TW4-3
TW4-23 TW4-6
TW4-4 TW4-14
PIEZ-4
MW-25MW-11
MW-02
MW-24
MW-29
MW-12 MW-05
MW-23
MW-16
MW-15
MW-14
MW-17
MW-03A
MW-03
MW-20
MW-21
MW-22
Cell No. 1
Mill Site
Cell No. 2
Cell No. 3
Cell No. 4A
WildlifePond
WildlifePond
WildlifePond
TW4-7
TWN-9 TWN-13
TWN-17
TWN-19
TWN-12
TWN-11
TWN-16
TWN-15
TWN-14
TWN-10
TWN-6
TWN-8TWN-5
TWN-7 TWN-18
TWN-3
TWN-2 TWN-4
TWN-1
5
10
15 20 25
25
5
5
30
2015
10 5
5

WESTWATER SEEP
ENTRANCE SPRING
CORAL CANYON SEEP
5440
5380
FROG POND
Lawzy Lake

PIEZ-5
5590
5610
5
5
8
5 5600
5620
5590
5610
5 5 8 5
5600
5 5 7 0
5 5 5 0
5530
5 5 1 0
5 4 90
5470
S:\Projects\IUC-001-01-001 Denison Mines\GIS\mapdocs\2011_WP_Nitrate_Response\20110121NitrateMap.mxd
Figure 22Stable Isotope Sampling WellsNitrate and ChlorideSource Investigation
1,200 0 1,200600Feet
Source(s): Aerial – Utah GIS Portal website, dated 2009;Wells – HGC, Inc., May 2008 report.
Legend
DUSA Property Boundary
Groundwater Elevation Contour(interval 10 ft)
Groundwater Elevation Contour(interval 5 ft)
Nitrate Concentration (mg/L)
Stable Isotope Sampling Well
Monitoring Well
Piezometer
Spring/Seep
Surface Water
Chloroform Monitoring Well
Nitrate Monitoring Well
Nitrate data from September, October, or November of 2009. A single data point was used for each well.

Tables

Table 1. Work Plan Schedule
Denison White Mesa Mill Nitrate and Chloride Investigation
Task No.Task and Subtask Description
1 2 3 4 5 6 7 8 9 10 11 12 13 14
1 HISTORICAL LAND USE AND GEOMORPHIC STUDY
Order and evaluate satellite imagery
2 GEOPROBE INVESTIGATION OF POTENTIAL NATURAL NITRATE RESERVOIR, 20 LOCATIONS
Borings, field tests
Laboratory analysis SPLP
3 GEOPROBE BORINGS IN POTENTIAL NITRATE SOURCE LOCATIONS, 13 BORINGS, 2 INFLUENT WATER SAMPLES
Borings, field tests
laboratory analysis SPLP and influent water
4 CORING STUDY TO EXPLORE FOR NATURAL NITRATE RESERVOIR
Core up to 4 locations
Laboratory preparation and SPLP analysis
5 CORING STUDY IN POTENTIAL NITRATE SOURCE LOCATIONS
Core up to 13 locations
Up to 13 locations, core to laboratory for preparation and SPLP
6 STABLE ISOTOPE STUDY, LABORATORY ANALYSIS
Water sampling from 6 existsing well locations, coordinate with quarterly groundwater monitoring event
Laboratory analysis
7 MASS BALANCE CALCULATIONS
Integrate information from other studies and evaluate potential sources
8 REPORT OF FINDINGS
Draft and Denison Review
Final
Month
Table 2
Laboratory Analytical Parameters by Task and Media
Table 1_Analyte Table 1-25-11.xls Page 1 of 1
SOIL AND ROCK
Geoprobe Borings
All field test kit tests: Nitrate and Chloride
Media:Soil
Analyte Method Container/Vol
Nitrate-Nitrite SPLP1 sealable plastic bag 1 qt
Total Keldal Nitrogen SPLP sealable plastic bag 1 qt
Chloride SPLP sealable plastic bag 1 qt
Coring Study
Media:Rock
Analyte Method Container/Vol
Nitrate-Nitrite SPLP sealable plastic bag 1 qt
Total Keldal Nitrogen SPLP sealable plastic bag 1 qt
Chloride SPLP sealable plastic bag 1 qt
GROUNDWATER
Stable Isotopes Study
Analyte Method Container/Vol Preservative Comments
d15N nitrate mass spectrometer 1-L HDP2 None means delta 15/14 ratio, seal tightly to eliminate evaporation
d18O nitrate mass spectrometer 1-L HDP None means delta 18/16 ratio, seal tightly to eliminate evaporation
d18O water mass spectrometer 1-L HDP None means delta 18/16 ratio, seal tightly to eliminate evaporation
dDeuterium water mass spectrometer 1-L HDP None seal tightly to eliminate evaporation
Nitrate-Nitrite 300 250 mL HDP H2SO4, cool
Total Kjeldal nitrogen 351.2 125 mL HDP none
Chloride 300 125 mL HDP cool
Follow-up notes:
1synthetic precipitation leaching procedure (SPLP) No. 1312
2HDP=High Density Plastic
Andy Freeman, Hall Environmental Laboratory: 345-3975
Chris Eastoe, University of Arizona Isotopic Laboratory: 520 621-1638
deuterium "heavy water", "2H", "heavy hydrogen"

Appendix A
Nitrate Extraction and Field Test Procedure

14
5. Electrical Conductivity Test
Soil samples for the electrical conductivity (EC) test are taken from the 0- to 3-inch depth. Bulked
soil samples from across the field can be collected, and two subsamples can be taken for analysis
(See Chapter 1, Sampling Guidelines).Electrical conductivity, pH, and soil nitrate are all
measured from the same soil subsample.
Materials needed to measure electrical conductivity (EC):
1/8-cup (30 mL) measuring scoop
120-mL plastic containers with lid
EC pocket meter (blue with black cap)
squirt bottle
calibration solution (0.01 M KCl)
distilled water
Extract Subsample
The soil sample should be thoroughly mixed before taking a subsample. Measure a 1/8-cup
level scoop subsample of soil and place it in the plastic container. If soil nitrates will be
measured on this subsample (Chapter 7), weigh the subsample for a more accurate estimate
of soil nitrates. Enter the subsample weight on the Soil Data worksheet.
Add Water to Subsample and Mix
Add 1/8-cup (30 mL) of distilled water to
the container with the subsample. The
resulting soil/water mixture equates to a
1:1 soil to water ratio on a volume basis.
Put the lid on the container and shake
vigorously about 25 times.
Measure and Record EC (See Calibration Tip)
Open the container and insert the EC pocket meter into the soil-water mixture. Take the
reading while the soil particles are still suspended in solution. To keep the soil particles
from settling, stir gently with the EC pocket meter. Do not immerse the meter above
the immersion level (See Appendix C, Figure 1c). Allow the reading to stabilize (stays
the same for about 10 seconds).
Enter the EC reading on the Soil Data worksheet in decisiemens per meter (dS/m). The
DiST WP 4 meter gives readings directly in dS/m. For the Microsensor 4 meter, divide
the reading by 10, and for the Microsensor 3 meter, divide the reading by 100 to get
readings in dS/m.
Save the soil-water mixture for the pH measurement (Chapter 6).
Turn the meter off. Thoroughly rinse meter with distilled water and replace cap.
Make sure the EC
meter is calibrated before
making a measurement.
See Appendix C for cali-
bration instructions.
1
2
3
4
Did You Know?
Excess salts in soil can be a
detriment to plant health. Salts
can also hamper water move-
ment into the soil and increase
the occurrence of surface com-
paction.
15
6. Soil pH Test
Use the same soil-water mixture prepared in the EC test to conduct the pH Test. If you are start-
ing with a fresh soil sample, read the introduction and follow Steps 1-3 in the EC Test Chapter
on preparing the sample.
Materials needed to measure pH:
1/8-cup (30 mL) measuring scoop
plastic specimen bottle
calibration buffer solutions
squirt bottle
pH pocket meter (red with black cap)
distilled water
Considerations: If the soil sample is saturated or very wet, a 1:1 ratio, on a volume basis, of soil
to water will not be obtained in the soil-water mixture (See Step 2, Chapter 5). Let the soil dry
before proceeding with Step 1 in Chapter 5. Also, a small amount of salts diffuse out of the pocket
pH meter; therefore, EC measurements should always be taken first when measuring both EC
and pH on the same sample.
Measure and Record pH
Make sure to periodically calibrate your pH meter (See Appendix C for instructions).
Wait about 10 to 15 minutes after the EC measurement before measuring the pH. This
gives the soil particles time to settle. Insert the pH pocket meter into the topmost
portion of the solution and turn the meter on. Wait until the reading stabilizes (0-30
seconds), and record the digital reading on the Soil Data worksheet.
Rinse Pocket Meter
Thoroughly rinse the electrode with distilled water.
Store the electrode with a few drops of the pH 7 buffer solution and replace the cap.
(See Appendix C on storage of pH meter)
Did You Know?
Soil acidification can also be an
indication of excessive N fertilizer
applications and N leaching loss.
1
2
16
7. Soil Nitrate Test (NO3
-)
Use the same sample prepared for the EC and pH tests to measure soil nitrates.If you are starting
with a fresh soil sample, read the introduction and follow Steps 1-3 in the EC Test Chapter on
preparing the sample.
Materials needed to measure soil nitrate:
filter paper
120-mL plastic container with lid
eye dropper
nitrate/nitrite test strips
stopwatch or timer
distilled water
Fold Filter
Fold the filter paper in half (into a semicircle).
Fold it again, but not quite into a quarter-circle.
Leave the edges a little uneven as in Figure 7.1
(A black line is drawn for demonstration purposes.)
Insert Filter Paper into Subsample
Open the filter paper into the shape of a cone and push
it (pointed part first) quickly into the jar with the
soil/water mixture until it touches the bottom of the
jar (Figure 7.2).Wait until about an eye dropper-
full of the solution has seeped through to the inside
of the filter paper. (Note: Inserting the filter
paper quickly prevents it from wetting up and
tearing as it is inserted.)
[For Steps 3 & 4, it would be helpful to first
familiarize yourself with the directions on the
side of the bottle of nitrate strips.]
Place Drops on Nitrate Strips
Using the eye dropper and one nitrate/nitrite test strip, place 1 or 2 drops of the filtered
solution on each of the strip's two pads.Note the time.
NOTE: One pad measures the amount of nitrite, and the other measures the amount of
nitrite and nitrate combined. Nitrite rarely occurs in measurable amounts in soils, so nitrite
readings from the test strips are not recorded.
1
3
2
Figure 7.2
Did You Know?
Soil nitrates are good measures of
plant-available nitrogen, but they
can be readily lost from the soil by
leaching and volatilization.
Figure 7.1
17
Measure and Record Nitrate
Align the nitrate/nitrite test strip with the bottom of the bottle with your thumb corre-
sponding to the diagram on the bottle.
After 60 seconds, compare the first pad (fur-
thest from your thumb) along the nitrate scale
as shown in Figure 7.3. Estimate the nitrate
amount according to the degree of color change.
Enter the value from the nitrate scale on the Soil
Data worksheet in ppm. This value is an esti-
mate of nitrate-N concentration in the extract.
Did You Know?
Water samples may be taken from drinking water, well water, tile drainage, drainage
ditches, and ponds. Dip a nitrate/nitrite test strip into the water and estimate the nitrate or
nitrite concentration from the color chart on the test strip bottle. This test can give you an
idea of how much N fertilizer is lost from the soil.(See Chapter 12).
CALCULATIONS:
Estimated (lb NO3-N/acre) =
(ppm extract NO3-N) x (depth of soil sampled in cm) x bulk density x 0.89
10
Exact (lb NO3-N/acre) =
(ppm NO3-N) x (volume water used) x (depth of soil sampled, cm) x bulk density x 0.89
(dry weight of soil) x 10
Volume water used = 30.0 mL + [dry weight of soil x soil water content (g/g)]
Note: The maximum nitrate-N reading on the nitrate/nitrite test strip container is 50 ppm. If the
sample reading falls into the 50 ppm category, the sample can be diluted to get a better estimate of
the actual amount over 50 ppm. To dilute the sample, fill the eye dropper with filtered solution and
place five drops in a plastic container. Add five drops of distilled water; mix gently by swirling the
container. Take a reading with a new test strip as stated in Step 4. Multiply the estimated nitrate-N
in ppm by 2 before using the calculations. If the nitrate reading falls into the category of 50 ppm
again, repeat the dilution steps, and multiply the estimated nitrate-N in ppm by 4.
Figure 7.3
4
NOTE: The nitrate test strips have a shelf-life.
Check the expiration date on the bottle.

Appendix B
Analytical Methods List

Appendix B

Analysis Methods for Soil Leachte
Synthetic Precipitation Leaching Procedure (SPLP): EPA Method 1312
Analysis for Nitrate and Chloride (Anions): EPA Method 300.0
Analysis for Total Kjeldhal Nitrogen (TKN): EPA Method 351.2