U.S. Department of the Interior 

U.S. Geological Survey 

Trace, Minor and Major Element Data for Ground Water Near 

Fairbanks, Alaska, 1999-2000 

by 

S.H. Mueller1

, R.J. Goldfarb1, G.L. Farmer2, R. Sanzolone1, M. Adams

1

, P.M. Theodorakos1, S.A. 

Richmond3

, R.B. McCleskey4 

Open-File Report 02-90 

2002

1

U.S. Geological Survey, DFC, PO BOX 25046, MS 973, Denver, CO 80225 2

Dept. of Geological Sciences University of Colorado, Boulder Colorado, 80309 3

University of Alaska Fairbanks, Fairbanks, AK 99775 4

U.S. Geological Survey, 3215 Marine St, Boulder, CO 80303 

Corresponding author’s email address: shmuelle@usgs.gov 

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey 

editorial standards (or with the North American Stratigraphic Code.) Any use of trade, product, or 

firm names is for descriptive purposes only and does not imply endorsement by the U.S. 

Government. 

1
TABLE OF CONTENTS 

INTRODUCTION................................................................................................3 

GEOLOGIC BACKGROUND, HYDROLOGY, AND MINERALIZATION...........................3 

METHODS OF STUDY........................................................................................ 3 

ANALYTICAL TECHNIQUES................................................................................4 

Inductively Coupled Plasma-Atomic Emission Spectrometry............................................. 4 

Inductively Coupled Plasma-Mass Spectrometry............................................................ 4 

Ion Chromatography............................................................................................. 4 

Alkalinity as CaCO3............................................................................................. 4 

Atomic Absorption Spectrometry.............................................................................. 4 

Ferrous Iron by Colorimetry....................................................................................4 

DESCRIPTION OF TABLES.................................................................................. 5 

Tables containing descriptive information.................................................................... 5 

Tables containing geochemical analyses...................................................................... 5

Abbreviations in tables...........................................................................................6 

ACKNOWLEDGEMENTS..................................................................................... 6 

REFERENCES CITED..........................................................................................6

LIST OF TABLES 

TABLE 1. Symbol and name of element and method of analyses.......................................7 

TABLE 2. Limits of determination for ICP-MS and ICP-AES...........................................8 

TABLE 3. Limits of determination for IC...................................................................9 

LIST OF FIGURES FILE NAME 

FIGURE 1. SHADED RELIEF MAP SHOWING SAMPLING LOCATIONS..................FIG1.PDF 

FIGURE 2. GENERALIZED GEOLOGIC MAP OF THE STUDY AREA......................FIG2.PDF 

2
INTRODUCTION 

A groundwater geochemical study was carried out from August 1999 to August 2000 near 

Fairbanks, Alaska. Groundwater samples were collected at two-month-intervals from 17 domestic water 

supply wells located throughout the Fairbanks (Fig 1) area to (1) comprehensively define the baseline 

geochemical signature of the groundwater, (2) examine the spatial variability, (3) examine any seasonal 

variability, and (4) determine the concentration of arsenic species in the groundwater. This report presents 

the methodology and analytical results for the groundwater samples taken during this study. 

GEOLOGIC BACKGROUND, HYDROLOGY, AND MINERALIZATION 

Fairbanks is located in east-central Alaska within what is known as the Yukon-Tanana terrane (YTT), 

which is described as a pericratonic block of late Paleozoic and older rocks that have experienced multiple 

episodes of metamorphism and deformation (Foster and others, 1994.) The dominant rocks exposed in the 

Fairbanks area are those of the Fairbanks Schist, a heterogeneous unit composed of quartzite and 

muscovite-quartz±garnet±biotite±chlorite schist that is intruded in places by Mississippian orthogneiss 

(Foster and others, 1994). Less common lithologies of the Fairbanks Schist include amphibolites, 

magnetite-rich biotite schist, and marble (Newberry and others, 1996). Other important units include: (1) 

metamorphosed andesite, rhyolite, and basalt of the Devonian Muskox Sequence; (2) slate, phyllite, 

quartzite, calcareous schist, impure marble and minor metarhyolite tuff of the Birch Hill Sequence; (3) 

Devonian-Mississippian eclogite-bearing schist, amphibolite and quartzite of the Chatanika assemblage; 

and (4) Tertiary basalt (Newberry and others, 1996) (Fig 2.) The bedrock units in this area of Fairbanks are 

poorly exposed and covered by as much as 100 m of Quaternary Fairbanks loess (Pewe, 1975). In addition, 

there are numerous widely scattered Cretaceous granitic rocks (110 Ma and 90 Ma) that intrude the various 

metamorphosed Paleozoic rocks. 

The younger of the two mid-Cretaceous intrusive events is spatially and temporally associated 

with the formation of lode gold deposits in the Fairbanks area. The auriferous quartz vein deposits are 

hosted by either granitic rocks (e.g. Ft. Knox), along the granitoid-schist boundary (e.g. Ryan Lode), solely 

in the schist itself (e.g. Hi-Yu deposit), or in eclogites (e.g. True North) (Metz, 1991; Newberry and others, 

1996). Where the mineralization is hosted in the granitic rocks, the ores show a Bi-Te-W signature and 

have very low (<< 1 volume percent) sulfide mineral contents. Where hosted in the other rocks, the ores 

have an As-Sb-Fe signature and have higher sulfide mineral abundances (~2-3 volume percent). The 

metasedimentary rocks surrounding the mineralized veins also may be sulfidized for tens to hundreds of 

meters. Much of the mineralization in the Fairbanks area is associated with multiple, northeast-trending 

faults and shear zones. In addition to the known lode gold deposits, there are extensive placer deposits 

located near Gilmore Dome and Pedro Dome to the northeast, and near the town of Ester to the southwest 

of Fairbanks (Metz, 1991; Newberry and others, 1996; McCoy and others, 1997). 

The hydrology of the Fairbanks area includes lowland alluvial aquifers consisting of gravel and loess 

deposits. Fracture controlled bedrock aquifers dominate the flow network in the upper valleys and higher 

elevations outside of the city proper. Groundwater flow in the alluvial aquifer is controlled by melt water 

from the Alaska Range and Tanana Valley uplands, with a predominately westward flow direction. The 

flow in upland fractured bedrock aquifers is controlled by changes in gradient. The upland aquifers are 

believed to enter the alluvial aquifers in the valley bottoms (Nelson, 1978). 

METHODS OF STUDY 

Water samples were taken from seventeen domestic wells. The samples were collected at the well 

intake to the pressure tank, prior to any filtration. Samples were taken during seven sampling runs, at twomonth-intervals, beginning in August, 1999 and ending in August, 2000. 

Well-rinsed five-gallon plastic buckets were used for sample collection. A PVC hose was 

attached to the hose bib and water was turned on. Specific conductance, temperature, and pH were 

measured at 5-10 minute intervals for as long as 45 minutes, or until the temperature stabilized between 3-

4° C and the pH and specific conductance stabilized. After these readings stabilized, samples for chemical 

analyses were then taken. The samples consisted of (1) an unacidified filtered sample for anion analysis; 

(2) an unacidified unfiltered sample for major, minor, and trace element analysis of both dissolved and 

3
suspended material; (3) an acidified filtered sample for major, minor, and trace element analysis of 

dissolved species; (4) an acidified filtered sample for iron speciation, and (5) an acidified filtered sample 

for arsenic speciation. All samples were kept cool on ice in the field and refrigerated in the laboratory until 

analysis. Samples were filtered with 0.45-micron disposable filters. All samples, except the anion sample, 

were collected in polyethylene acid rinsed bottles. Samples for major and trace element analyses were 

acidified to a pH ~2 with ultra-pure nitric acid. Samples for both iron and arsenic speciation were acidified 

with ultra pure hydrochloric acid to a pH~2 and stored in amber bottles, or wrapped in plastic and 

aluminum foil, to avoid exposure to sunlight. 

ANALYTICAL TECHNIQUES 

A large number of chemical elements were analyzed using a variety of quantitative and semi-quantitative 

analytical techniques. Table 1 shows the various elements determined and the analytical methods used for 

each. What follows is a brief description, including references, for each analytical method. Descriptions for 

techniques, including quality assurance/quality control (QA/QC) protocol for most of the analytical 

methods, are found in Aborgast (1996). U.S. Geological Survey laboratories analyzed all samples. 

Inductively Coupled Plasma-Atomic Emission Spectrometry 

In this multi-element technique, concentrations of major (Al, Ca, Fe, K, Mg, Na, and Si) and selected minor 

and trace elements were determined using a Leeman Labs-DRE ICP-AES. Major cations were analyzed 

using the radial view whereas the axial view was used for minor and trace metals. The limits of 

determination are shown in Table 2. 

Inductively Coupled Plasma-Mass Spectrometry 

Acidified filtered and unfiltered water samples were analyzed for 44 elements by ICP-MS using a method 

developed by the U.S. Geological Survey (Meier et al., 1994). This method is used to determine the 

elements directly on the water samples without need for any pre-concentration or dilution. Elemental

detection limits are in the sub-part per billion range, and the working linear range is six or more orders of

magnitude. This method is most useful for trace and minor elements in the parts per billion range, whereas 

analyses for major elements in the parts per million range are less accurate and better determined by ICPAES analysis. 

Ion Chromatography 

The anions Cl-

, F-, NO3

-

, and SO4

2- were determined by ion chromatography on unfiltered, unacidified

samples using the method of Theodorakos (written communication, 2002). Lower determination limits are 

shown in Table 3. 

Alkalinity as CaCO3 

Alkalinity was measured both in the field and in the laboratory. In the field, a 100 ml sample was titrated 

using 0.01630 N or 1.60N sulfuric acid to a final pH of 4.5 using a digital titrator. The alkalinity in the lab 

was measured using the Preset Endpoint method described by Theodorakos (written communication, 2002), 

where the sample is titrated with a specified concentration of H2SO4 until a pH of 4.5 is reached. 

Atomic Absorption Spectrometry 

The concentrations of arsenic (III) and arsenic (V) species were determined using a modification of the 

method used by Ficklin (1983). However, due to discrepancies between the As3++As5+ totals and the As 

totals from the ICP-MS method, the As5+ was determined by the difference between the ICP-MS total and 

the GFAAS As3+ concentrations. The acidified water samples were passed through ion exchange columns 

packed a with strong anion exchange resin (acetate form.) In this technique, the arsenite passes through the 

column, whereas arsenate is retained until eluted with 0.12 M hydrochloric acid. The concentrations of the 

species were then determined using graphite-furnace atomic absorption spectrometry with a detection limit 

of 3 ppb for each species. 

Ferrous Iron by Colorimetry 

Ferrous iron was determined by colorimetric methods using a Hach 2010ä photo spectrometer. Samples 

were introduced into an AccuVac Ampulä and mixed rapidly. The phenanthroline reagent reacts with the 

ferrous iron in the sample to form an orange color in proportion to the ferrous iron concentration. The 

4
ampule was then placed into the spectrophotometer and the concentration was measured (Theodorakos, 

written communication, 2002). For concentrations higher than 3 ppm, samples were diluted and reanalyzed. 

DESCRIPTION OF TABLES 

Below are brief descriptions of the various tables and fields within those tables. First are tables containing 

sample and site descriptive information, followed by tables containing chemical analyses. These data tables 

can be found in the two files associated with this report. 

Tables containing descriptive information: 

TblSampleSiteInfo Contents 

Fields: 

Site_ID 

Field_No 

Latitude 

Longitude 

Coordinate Source 

Descrip 

TblFieldData Contents 

Fields: 

Field_No 

Date_Coll 

Time_Coll 

Temp_C 

pH 

Cond_mS/cm 

DO_ppm 

Alk_lab_ppm 

Alk_Field ppm 

Tables containing geochemical analyses: 

site identifier 

corresponding field number 

latitude in decimal degrees 

longitude in decimal degrees 

how coordinates were obtained 

brief description of site

field number 

date collected

time collected 

water temperature at site, degrees Celsius 

water pH at site

water conductivity, microsiemens/centimeter 

dissolved oxygen in water at site, parts per million 

water alkalinity in lab, as parts per million CaCO3 

water alkalinity at site, as parts per million CaCO3

The following fields are common to all geochemical analyses: 

Field_No field number 

Lab_No sample laboratory assigned number 

Job_No job number for job in which sample was analyzed 

Sample_Desc description of how sample was prepared for analysis

These fields listed above apply to the tables listed below:

TblAnions anion analyses, filtered/unacidified water samples 

TblCatFA ICP-MS cation analyses, filtered/acidified water samples 

TblCatRaw ICP-MS cation analyses, unfiltered/acidified water samples 

TblCat-AES ICP-AES select major, minor and trace elements, filtered/acidified samples 

TblFe2+ Fe2+ analyses, water filtered/acidified

TblAs3+ As3+ analyses, water filtered/acidified

The Field number consists of the following information:

The first two numbers indicate the year (ie. 99=1999 and 00= 2000) 

The next number indicates the sampling run, sampling runs corresponding to the following months:

1=August, 1999 

2=October, 1999 

3=December, 1999 

4=February, 2000 

5=April, 2000 

5
 6=June, 2000 

7=August, 2000 

The final numbers after the dash refer to the sampling site (site numbers 06 through 22.) Therefore, a 

sample taken at site number 22, in February of 2000, would have the following Site_ID= 004-22 

Abbreviations in tables 

N.S. No sample taken 

N.A. No analyses done 

B.D.L Below detection limit for method used 

- No Data 

ACKNOWLEDGEMENTS 

We would like to thank Rainer Newberry, Larry Hinzman, Bob Bolton, Kenji Yoshikawa, Trevor White, 

Michael Lilly and Mike McKinnon for their assistance with logistics and sampling. We would also like to 

thank Paul Lamothe, Al Meier, Kirk Nordstrom, and Philip Verplanck for their input and assistance with 

analytical techniques. And finally we would like to thank Tom DeLong, Bob Ritchie, Joanna Roth, Larry 

Hinzman, Rainer Newberry, Joan Braddock, Renee Crane, ABR Inc., Kenji Yoshikawa, Elrita Maggofin, 

Sue Bishop, Chris Stark, Kent Schwagerle, Dennis Trabant, Bonnie Borba, and Laura Jacobs, for allowing 

us access their homes to obtain samples for this study. 

REFERENCES CITED 

Aborgast, B.F., editor, Analytical methods for the Minerals Resource Surveys Program, 

U.S. Geological Survey Open-File Report 96-525, 248 p. 

Ficklin, W.H., 1983, Seperation of Arsenic(III) and Arsenic(V) in Ground Waters by Ion-Exchange. 

Talanta, 30, 5, 371-373. 

McCoy, D., Newberry, R.J., Layer, P., DiMarchi, J.J., Bakke, A., Masterman, J.S. and Minehane, D.L., 

1997, Plutonic-related gold deposits of interior Alaska, in Goldfarb, R.J., and Miller, L.D., eds., 

Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 191-124. 

Meier, A.L., Grimes, D.J., and Ficklin, W.H., 1994, Inductively coupled plasma mass spectrometry—A 

powerful analytical tool for mineral resource and environmental studies [abs], in Carter, L.M.H., 

Toth, M.I., and Day, W.C., eds., USGS Research on Mineral Resources—1994, Part A—Program 

and Abstracts, Ninth V.E. McKelvey Forum on Mineral and Energey Resources: U.S. Geologcial 

Survey Circular 1103-A, p. 67-68. 

Metz, P.A., 1991, Metallogeny of the Fairbanks Mining District, Alaska and Adjacent 

Areas, University of Alaska, School of Mineral Engineering, Minerals Research Industry 

Laboratory Report 90, 370 p. 

Newberry, R.J., Bundtzen, T.K., Clautice, K.H., Combellick, R.A., Douglas, T., Laird, G.M., Liss, S.A., 

Pinney, D.S., Reifenstuhl, R.R., and Solie, D.N., 1996, Preliminary geologic map of the Fairbanks 

Mining District, Alaska: Alaska Division of Geological and Geophysical Surveys, Public Data 

File 96-12, 14 p., 2 sheets. 

Theodorakus, P.M., 2002, written communication 1/24/2002. 

6
Table 1. Symbol and name of elements and ions determined and method of analysis. Method abbreviations 

are ICP-MS=Inductively Coupled Plasma-Mass Spectrometry, ICP-AES=Inductively Coupled PlasmaAtomic Emission Spectrometry, GFAAS=Graphite Furnace Atomic Adsorption Spectrometry, IC=Ion 

Chromatography, CaCO3=Alkalinity, COLOR=Ferrous iron by colorimetric techniques. 

Element ICP-MS ICP-AES GFAAS IC CaCO3 COLOR 

Ag, silver X

Al, Aluminum X

As, Arsenic X X

As3+, trivalent arsenic X

Ba, Barium X

Be, Beryllium X

Bi, Bismuth X

Ca, Calcium X X

Cd, Cadmium X X

Ce, Cerium X

Co, Cobalt X

Cr, Chromium X

Cs, Cesium X

Cu, Copper X X

Fe, Iron X X

Fe2+, Divalent Iron X

K, Potassium X X

La, Lanthanum X

Li, Lithium X

Mg, Magnesium X X

Mn, Manganese X X

Mo, Molybdenum X

Na, Sodium X X

Ni, Nickel X

P, Phosphorus X

Pb, Lead X

Rb, Rubidium X

Sb, Antimony X

Se, Selenium X

Si, Silica X X

Sr, Strontium X X

U, Uranium X

V, Vanadium X

W, Tungsten X

Zn, Zinc X X

Cl-

, Chloride X

F-

, Fluoride X

NO3 

-

, Nitrate X

SO4 

2-, Sulfate X

Alkalinity as Calcium Carbonate X

7
Table 2. Lower limits of determination for ICP-MS and ICP-AES. 

Lower Determination Limit 

ELEMENT ICP-MS ICP-AES 

Parts per Million 

Ca 0.05 1

Mg 0.01 1

Na 0.01 1

K 0.01 1

SiO2 0.25 1

Parts per billion 

Ag 0.01

Al 0.01

As 0.2 30

Ba 0.02 50

Be 0.05

Bi 0.01

Cd 0.02 10

Ce 0.01

Co 0.02

Cr 1

Cs 0.01

Cu 0.5 10

Fe 10 10

Fe2+ N.A.

La 0.01

Li 0.1 10

Mn 0.01 10

Mo 0.02

Ni 0.1

P 0.01

Pb 0.05

Rb 0.01

Sb 0.02

Se 0.2

Sr 0.02 1

U 0.01

V 0.1

W 0.02

Y 0.01

Zn 0.5 10

8
Table 3. Lower determination limit for IC in parts per million. 

ELEMENT 

IC 

Lower Determination Limit 

Cl- 0.1

F- 0.05

NO3 

- 0.5

SO4 

- 0.5

9
10
11
12