National Water-Quality Assessment Program

Electron Donor Concentrations in Sediments and Sediment 

Properties at the Agricultural Chemicals Team Research Site 

near New Providence, Iowa, 2006–07

Data Series 737

U.S. Department of the Interior

U.S. Geological Survey

Electron Donor Concentrations in 

Sediments and Sediment Properties at the 

Agricultural Chemicals Team Research Site 

near New Providence, Iowa, 2006–07

By Bijesh Maharjan, Scott F. Korom, and Erik A. Smith

National Water-Quality Assessment Program

Data Series 737

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2013

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Suggested citation:

Maharjan, Bijesh, Korom, S.F., and Smith, E.A., 2013, Electron donor concentrations in sediments and sediment properties at the agricultural chemicals team research site near New Providence, Iowa, 2006–07: U.S. Geological Survey 

Data Series 737, 17 p.
iii

Foreword

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effective management of water, biological, energy, and mineral resources (http://www.usgs.

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to support national, regional, State, and local information needs and decisions related to 

water-quality management and policy (http://water.usgs.gov/nawqa). The NAWQA Program 

is designed to answer: What is the quality of our Nation’s streams and groundwater? How are 

conditions changing over time? How do natural features and human activities affect the quality 

of streams and groundwater, and where are those effects most pronounced? By combining 

information on water chemistry, physical characteristics, stream habitat, and aquatic life, the 

NAWQA Program aims to provide science-based insights for current and emerging water issues 

and priorities. From 1991 to 2001, the NAWQA Program completed interdisciplinary assessments and established a baseline understanding of water-quality conditions in 51 of the Nation’s 

river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/studies/

study_units.html).

National and regional assessments are ongoing in the second decade (2001–2012) of the 

NAWQA Program as 42 of the 51 Study Units are selectively reassessed. These assessments 

extend the findings in the Study Units by determining water-quality status and trends at sites 

that have been consistently monitored for more than a decade, and filling critical gaps in 

characterizing the quality of surface water and groundwater. For example, increased emphasis 

has been placed on assessing the quality of source water and finished water associated with 

many of the Nation’s largest community water systems. During the second decade, NAWQA is 

addressing five national priority topics that build an understanding of how natural features and 

human activities affect water quality, and establish links between sources of contaminants, the 

transport of those contaminants through the hydrologic system, and the potential effects of contaminants on humans and aquatic ecosystems. Included are studies on the fate of agricultural 

chemicals, effects of urbanization on stream ecosystems, bioaccumulation of mercury in stream 

ecosystems, effects of nutrient enrichment on aquatic ecosystems, and transport of contaminants to public-supply wells. In addition, national syntheses of information on pesticides, volatile organic compounds (VOCs), nutrients, trace elements, and aquatic ecology are continuing. 

The USGS aims to disseminate credible, timely, and relevant science information to address 

practical and effective water-resource management and strategies that protect and restore 

water quality. We hope this NAWQA publication will provide you with insights and information 

to meet your needs, and will foster increased citizen awareness and involvement in the protection and restoration of our Nation’s waters. 
iv

The USGS recognizes that a national assessment by a single program cannot address all waterresource issues of interest. External coordination at all levels is critical for cost-effective management, regulation, and conservation of our Nation’s water resources. The NAWQA Program, 

therefore, depends on advice and information from other agencies—Federal, State, regional, 

interstate, Tribal, and local—as well as nongovernmental organizations, industry, academia, and 

other stakeholder groups. Your assistance and suggestions are greatly appreciated.

 William H. Werkheiser 

USGS Associate Director for Water
v

Contents

Foreword ........................................................................................................................................................iii

Acknowledgments.........................................................................................................................................v

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Methods...........................................................................................................................................................2

Site Characteristics..............................................................................................................................2

Field and Laboratory Methods............................................................................................................2

Electron Donor Concentrations and Sediment Properties .....................................................................4

References Cited............................................................................................................................................5

Appendix 1. Supplemental Tables............................................................................................................7

Appendix 2. Supplemental Figures........................................................................................................13

Figures

1. Map showing location of the study site and borehole sampling locations 

within the study site .....................................................................................................................3

2. Graph showing x-ray diffraction scan of sediment sample C1 (2.44–3.66 

meters)............................................................................................................................................5

Tables

1. Location of core sampling sites and sampling dates .............................................................4

2. Quantifiable detection limits of analytical methods used for quantification 

of electron donors ........................................................................................................................4

Acknowledgments

Funding for this research was provided by a U.S. Geological Survey (USGS) National Institutes 

of Water Resources National Competitive Grant, number 2006ND126G. Assistance for this work 

was provided by Paul Capel and Steve Kalkhoff, both of the USGS.

The authors also gratefully acknowledge collaborations with Kanishka Marasinghe, of the University of North Dakota, and his assistance with his x-ray diffractometer.
vi

Conversion Factors

SI to Inch/Pound

Multiply By To obtain

Length

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

meter (m) 1.094 yard (yd) 

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Elevation, as used in this report, refers to distance above the vertical datum.

Symbols 

> greater than

< less than

≤ less than or equal to

± plus or minus

® registered trademark

Abbreviations 

Fe(II) ferrous iron

HCl hydrochloric acid

IC inorganic carbon

IS inorganic sulfide

OC organic carbon

OS organic sulfur

USGS U.S. Geological Survey

XRD x-ray diffraction
Electron Donor Concentrations in Sediments and Sediment 

Properties at the Agricultural Chemicals Team Research 

Site near New Providence, Iowa, 2006–07

By Bijesh Maharjan, Scott F. Korom, and Erik A. Smith

Abstract

The concentrations of electron donors in aquifer sediments are important to the understanding of the fate and 

transport of redox-sensitive constituents in groundwater, such 

as nitrate. For a study by the U.S. Geological Survey National 

Water-Quality Assessment Program, 50 sediment samples 

were collected from below the water table from 11 boreholes 

at the U.S. Geological Survey Agricultural Chemicals Team 

research site near New Providence, Iowa, during 2006–07. All 

samples were analyzed for gravel, sand (coarse, medium, and 

fine), silt, clay, Munsell soil color, inorganic carbon content, 

and for the following electron donors: organic carbon, ferrous 

iron, and inorganic sulfide. A subset of 14 sediment samples 

also was analyzed for organic sulfur, but all of these samples 

had concentrations less than the method detection limit; 

therefore, the presence of this potential electron donor was 

not considered further. X-ray diffraction analyses provided 

important semi-quantitative information of well-crystallized 

dominant minerals within the sediments that might be contributing electron donors. 

Introduction

Nitrate is the most common groundwater contaminant, 

and because of growing anthropogenic sources, nitrate pollution is increasing (Korom, 1992). Nitrogen sources to groundwater can include chemical fertilizer, animal manure, wastewater, and atmospheric deposition. One of the processes by 

which nitrate is removed from groundwater is denitrification, 

which is the microbially mediated reduction of nitrate. Relatively non-reactive molecular nitrogen is the terminal product 

of this oxidation-reduction (redox) reaction (Korom, 1992). 

There are three requirements for denitrification: bacteria capable of mediating the reaction, low oxygen concentrations, and 

a supply of electron donors (Firestone, 1982). Korom (1992) 

concluded that the supply of electron donors is the critical 

factor for groundwater denitrification. In the absence of these 

electron donors, bacteria will not reduce nitrate. 

Typically, the supply of electron donors associated with 

subsurface sediments is larger than the supply dissolved in 

groundwater (Kennedy and others, 1998; Hartog and others, 

2005; Everett and others, 2006). Hartog and others (2002) 

and Helvoort and others (2007) noted that finer fractions of 

sediment are more reactive than coarser fractions. Electron 

donors associated with denitrification include organic carbon 

(Korom, 1992; McMahon and others, 1999; Rivett and others, 

2008), minerals bearing ferrous iron [Fe(II)] (Postma, 1990; 

Ernstsen, 1996; Senn and Hemond, 2002) and sulfur, both 

as organic (Bohlke and others, 2002) and inorganic (mainly 

pyrite) (Korom and others, 2005; Schwientek and others, 

2008; Majumder and others, 2008) species.

The concentrations of electron donors in aquifer sediments are important to the understanding of the fate and transport of redox-sensitive constituents in groundwater, such as 

nitrate. A study of electron donor concentrations in sediments 

and sediment properties was conducted for the U.S. Geological Survey (USGS) National Water-Quality Assessment 

Program. For this study, 50 sediment samples were collected 

from below the water table from 11 boreholes at the USGS 

Agricultural Chemicals Team research site near New Providence, Iowa, during 2006–07. All samples were analyzed for 

gravel, sand (coarse, medium, and fine), silt, clay, Munsell soil 

color, inorganic carbon content, and for the following electron donors: organic carbon (OC), ferrous iron [Fe(II)], and 

inorganic sulfide (IS). A subset of 14 sediment samples also 

was analyzed for organic sulfur (OS), but all of these samples 

had concentrations less than the method detection limit; 

therefore, the presence of this potential electron donor was not 

considered further. This report summarizes the electron donor 

concentrations in sediments and sediment properties that 

were analyzed in samples collected at the research site during 

2006–07. 
2 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Methods

Site Characteristics

The South Fork Iowa River watershed is part of the Iowa 

River watershed and is representative of corn and soybean 

row cropping in the Midwest (Kalkhoff and others, 2000). 

The South Fork Iowa River watershed consists of a lowrelief modern flood plain underlain by alluvial deposits and 

till, bounded by slightly higher relief ridges. Underlying the 

modern flood plain, surficial deposits of the DeForest Formation are dominated by very dark gray to brown, noncalcareous 

to calcareous, sandy loam alluvium with variable thicknesses 

from less than (<) 1 to 5 meters (m; Quade and Giglierano, 

2006). Underlying the DeForest Formation, the Noah Creek 

Formation consists of dark yellowish brown medium to coarse 

gravelly sand ranging from 4.5 to 12 m. With some variability, the Noah Creek Formation is underlain by till deposits of 

the Dows Formation-Morgan Member. These till deposits are 

stratified loam to silt loam, grayish brown and quite variable 

in thickness, ranging from 3 to 5 m (Quade and Giglierano, 

2006).

Elevations at the research site (fig. 1) range from approximately 300 m, measured from the North American Vertical 

Datum of 1988, in the upper part of the watershed to approximately 285 m. Surficial deposits near the USGS streamgage, 

South Fork Iowa River NE of New Providence, Iowa (USGS 

05451210), are dominated by alluvium of the DeForest Formation and valley train outwash deposits of the Noah Creek 

Formation. 

Field and Laboratory Methods

Fifty subsurface sediment samples were collected at 

depths below the water table from 11 boreholes at the research 

site (fig. 1 and table 1). A direct push coring unit (Geoprobe® 

Model 540MT, Salina, Kansas) mounted to a skid loader was 

used to collect 50 subsurface sediment samples in acrylic 

sleeves: 14 were collected in November 2006, 30 in May 

2007, and 6 in November 2007. Upon collection, samples 

were capped at both ends, put on ice, and transported to the 

University of North Dakota for analysis. All samples were 

moved to plastic storage containers, homogenized by gentle 

mixing, labeled, and stored in high-density polyethylene containers in a freezer for subsequent analysis. 

Particle sizes < 0.0625 millimeters (mm) were determined by the hydrometer method of sedimentation analysis, 

and sizes great than (>) 0.0625 mm were determined by wetsieve analysis (American Society for Testing and Materials, 

1998). Sediment grains were classified into gravel (> 2.0 mm), 

sand [less than or equal to (≤) 2.0 mm and > 0.0625 mm], 

silt (≤ 0.0625 mm and > 0.004 mm), and clay (≤ 0.004 mm). 

Munsell soil color classification was done for all the sediment 

samples.

Sediment mineralogy was analyzed by using x-ray diffraction (XRD) with an X’Pert Advanced XRD (PANanalytical B.V.) diffractometer. To prepare the sediment samples for 

XRD, about 10 grams of each sediment sample was ground 

with a mortar and pestle with the gravel fraction removed 

before grinding. The ground sediment sample was then left 

to air-dry overnight. The air-dried sample was then sieved 

through a No. 230 sieve and collected in a glass vial and 

labeled. Samples were kept in a sample holder and mounted in 

the diffractometer in sets consisting of as many as 10 samples. 

The XRD scans acquired from the analyses were later matched 

with the standard mineral database contained within the 

X’Pert Advanced XRD software. Two samples were scanned 

before and after acidification to confirm the loss of dolomite, 

CaMg(CO3)2, and calcite, CaCO3, by acidification. 

Only the sediments smaller than gravel (<2.0 mm) 

were analyzed for electron donor and inorganic carbon (IC) 

concentrations. Each sample was first oven-dried overnight at 

103 degrees Celsius and ground into fine powder before any 

chemical analysis. Large concentrations of IC in the subsurface sediments, if present, can obscure the quantification of 

OC concentrations (Shimadzu Corporation, 2001). Thus, after 

IC analysis and before OC analysis, IC was removed from 

each sample by immersing the pulverized sediment samples 

in water acidified to a pH <2 with concentrated hydrochloric 

acid (HCl), a volatile acid (Shimadzu Corporation, 2001). 

Then, the acidified sediments were filtered and weighed; the 

mass lost during acidification was considered to be inorganic 

carbon. Subsequent analysis by the Shimadzu TOC analyzer, 

a high-temperature combustion method for determining OC 

concentrations (Churcher and Dickhout, 1986), confirmed that 

this method effectively removed inorganic carbon from the 

sediment samples. 

Inorganic sulfide (IS) was determined by chromium 

reduction, modified slightly by using larger amounts of 

reagents (Canfield and others, 1986). Concentrations of Fe(II) 

were analyzed through wet chemical extraction by adopting 

methods used by Kennedy and others (1999). The results of 

total Fe(II) were computed by combining the Fe(II) recovered 

by the wet chemical extraction method plus Fe(II) corresponding stoichiometrically to IS [as pyrite (FeS2

)]. Concentrations 

of OS were analyzed using a Leco SC-432 DR Sulfur Analyzer. The detection limits of the various analytical methods 

for the electron donors are presented in table 2; the detection 

limit for IC was 0.003 percent. 

Analyses of a standard for each electron donor were performed to assess the accuracy and precision of the analytical 

methods. Dextrose (C6H12O6) was used as the standard for OC 

analysis and had average recoveries of 99.8 percent plus or 

minus (±) 3.4 percent (3 samples). Pyrite (FeS2) was the standard for IS analysis and had average recoveries of 90.6 percent 

± 0.3 percent (3 samples). For Fe(II) analysis, siderite (FeCO3) 

served as the standard and had average recoveries of 88.4 percent ± 2.3 percent (7 samples).
Methods 3

05451210

0 2 4 8 MILES

0 2 4 8 KILOMETERS

93°40' 93°30' 93°20' 93°10'

42°30'

42°20'

South Fork Iowa River 

watershed

New Providence

WRIGHT

HAMILTON HARDIN

FRANKLIN South

Fork

Iowa

River

Cr

Tipton

96° 94° 92°

43°

42°

41°

0 75 150 METERS

0 75 150 FEET

EXPLANATION

Site location

U.S. Geological Survey 

streamgage and 

identification

Borehole location and

number

05451210

N

1

2

2

3

4

5

6

7

8

9

10

IOWA

Figure 1. Location of the study site and borehole sampling locations within the study site.
4 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Table 1. Location of core sampling sites and sampling dates.

[Latitude and longitude, in degrees, minutes, seconds]

Core 

no.

Latitude Longitude Sampling 

date

1 42° 18’ 53.6” 93° 09’ 24.6” 11–02–2006

2 42° 18’ 52.5” 93° 09’ 20.2” 11–02–2006

3 42° 18’ 51.8” 93° 09’ 17.7” 11–03–2006

4 42° 18’ 51.0” 93° 09’ 14.9” 11–03–2006

5 42° 18’ 55.4” 93° 09’ 24.3” 05–14–2006

6 42° 18’ 54.3” 93° 09’ 20.4” 05–14–2006

6.1 42° 18’ 54.4” 93° 09’ 20.0” 11–13–2007

7 42° 18’ 53.5” 93° 09’ 17.2” 05–15–2006

8 42° 18’ 52.9” 93° 09’ 15.2” 05–15–2006

9 42° 18’ 51.7” 93° 09’ 10.8” 05-15–2006

10 42° 18’ 49.7” 93° 09’ 11.8” 05–15–2006

Electron donor Quantifiable detection limit 

(percent)

Organic carbon (OC) 0.02

Inorganic sulfide (IS) .003

Ferrous iron [Fe(II)] .003

Organic sulfur (OS) .01

Table 2. Quantifiable detection limits of analytical methods used 

for quantification of electron donors.

Electron Donor Concentrations and 

Sediment Properties

All 50 sediment samples were analyzed for gravel, sand 

(coarse, medium, and fine), silt, and clay contents. The results 

of the texture analysis are given in table 1–1 in appendix 1. 

Detailed results from the textural analyses containing the relative amounts of course, medium, and fine sand-sized fractions 

are presented in table 1–2 in appendix 1. The Munsell soil 

colors for the sediment samples are presented in table 1–3 in 

appendix 1. 

The XRD scans showed a substantial amount of quartz, 

dolomite, and calcite in some sediment samples, with examples shown in figure 2–1 in appendix 2. No significant peaks 

for minerals potentially responsible for electron donors in the 

samples were found, with the exception of small peaks for 

amphibole and clinochlore. Both of these minerals, potentially containing Fe(II), were detected in almost all of the 

XRD scans. However, other related peaks of amphibole and 

clinoclore could not be found as verification. Commonly, 

XRD detection limits for minerals range from 1 to 3 percent, 

by mass, depending on background noise, peak resolution of 

the diffractogram pattern, and sample preparation (Zachara 

and others, 2004). The chemical analysis showed that all the 

electron donors were present at concentrations < 1 percent 

by mass, which indicated that the minerals bearing Fe(II) or 

IS are not detectable by XRD scans. For aquifer sediment 

samples with poly-mineral mixtures, default searching by the 

X’Pert Advanced XRD software provides definitive results of 

the major minerals like quartz, feldspar, dolomite, and calcite. 

However, for Fe(II)- and IS-bearing minerals, closer observations were required. Sediment samples presented were randomly selected for XRD analysis (appendix 2) and all of them 

showed similar peaks, which is to be expected because all the 

samples analyzed were collected from the same field site.

Under HCl treatment as described in the “Field and Laboratory Methods” section, the sediment samples yielded IC concentrations with an average content of 9 percent by mass, with 

a few as high as 18 percent content (table 1–4 in appendix 1). 

This is to be expected because XRD scans of these sediments 

revealed high peaks of dolomite and calcite, as shown in figure 2. Additional XRD scans of other sediment samples from 

this site are included in figure 2–1 in appendix 2.

The OC content in the sediments averaged 0.13 percent 

by mass. The OC concentrations are presented in table 1–4. 

The IS content in the sediments averaged 0.033 percent by 

mass, with a few samples having IS concentrations less than 

the detection limit of 0.003 percent (table 1–5 in appendix 1). 

A subset of 14 sediment samples was analyzed for OS concentrations (table 1–1), but all of these concentrations were less 

than the detection limit of 0.01 percent by mass. The Fe(II) 

content in the sediments averaged 0.24 percent by mass (table 

1–6 in appendix 1).
References Cited 5

0 

1,000 

2,000 

0 10 20 30 40 50 60 70 80 

Intensity, in counts

2-theta position

Amp Ccl

Qz

Pf Af

Qz

Pf

Af

C

Do Qz

Qz

Qz

Do

Qz

Qz

Qz

Qz

Do

Qz

Do

C

Pf

Af

Amp

Ccl 

Quartz

Dolomite

Calcite

Plagioclase

Alkali feldspar

Amphibole

Clinochlore 

10,208 EXPLANATION

Figure 2. X-ray diffraction scan of sediment sample C1 (2.44–3.66 meters).

References Cited

American Society for Testing and Materials, 1998, Standard 

test method for particle-size analysis of soils, volume 04.08: 

West Conshohocken, Pa., American Society for Testing and 

Materials.

Bohlke, J.K., Wanty, R., Tuttle, M., Delin, G., and Landon, M., 

2002, Denitrification in the recharge area and discharge area 

of a transient agricultural nitrate plume in a glacial outwash 

sand aquifer, Minnesota: Water Resources Research, v. 38, 

no. 7, p. 10–1 to 10–26. 

Canfield, D.E., Raiswell, Robert, Westrich, J.T., Reaves, C.M., 

and Berner, R.A., 1986, The use of chromium reduction in 

the analysis of reduced inorganic sulfur in sediments and 

shales: Chemical Geology, v. 54, p. 149–155.

Churcher, P.L., and Dickhout, R.D., 1987, Analysis of ancient 

sediments for total organic carbon—Some new ideas: Journal of Geochemical Exploration, v. 29, no. 1–3, p. 235–246.

Ernstsen, Vibeke, 1996, Reduction of nitrate by Fe2+ in clay 

mineral: Clays and Clay Minerals, v. 44, no. 5, p. 599–608.

Everett, J.W., Kennedy, L.G., and Gonzales, J., 2006, Natural 

attenuation assessment using mineral data: Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management, v. 10, no. 4, p. 256–263.

Firestone, M.K., 1982, Biological denitrification in agricultural soils, in Stevenson, F.J., ed., Nitrogen in agricultural 

soils: American Society of Agronomy Monograph 22, 

p. 289–326.

Hartog, Niels, Griffioen, Jasper, and Van Der Weijden, C.H., 

2002, Distribution and reactivity of O2

-reducing components in sediments from a layered aquifer: Environmental 

Science and Technology, v. 36, no. 11, p. 2,338–2,344.

Hartog, Niels, Griffioen, J., and Bergen, P.F.V., 2005, Depositional and paleohydrogeological controls on the distribution 

of organic matter and other reactive reductants in aquifer 

sediments: Chemical Geology, v. 216, p. 113–131.

Helvoort, P.V., Griffioen, J., and Hartog, N., 2007, Characterization of the reactivity of riverine heterogeneous sediments 

using a facies-based approach; the Rhine–Meuse delta (The 

Netherlands): Applied Geochemistry, v. 22, p. 2,735–2,757.
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Schnoebelen, D.J., Sadorf, E.M., Porter, S.D., and Sullivan, 

D.J., 2000, Water quality in the eastern Iowa basins, Iowa 

and Minnesota, 1996–98: U.S. Geological Survey Circular 

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Green, V., 1998, Iron and sulfur mineral analysis methods 

for natural attenuation assessments: Bioremediation Journal, 

v. 2, no. 3–4, p. 259–276.

Kennedy, L.G., Everett, J.W., Dewers, T., Pickins, W., and 

Edwards, D., 1999, Application of mineral iron and sulfide 

analysis to evaluate natural attenuation at fuel contaminated 

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aquifer: Ground Water Monitoring and Remediation, v. 25, 

no. 1, p. 79–89.

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Machida, M., 2008, An exploration of nitrate concentrations 

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Appendix 1. Supplemental Tables 7

Appendix 1. Supplemental Tables
8 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Table 1–1. Sample name, depth, and results of textural and chemical analyses (in percent) for the sediment 

samples.

[Analyses values are in percent; IC-CO3

-

, inorganic carbon as carbonates; OC, organic carbon; IS, inorganic sulfide; Fe(II), ferrous iron; 

OS, organic sulfide; <, less than; --, not determined]

Samples Texture analysis Chemical analysis

Borehole 

no.

Depth

(meters) Gravel Total sand Silt Clay IC-CO3

- OC IS Fe(II) OS

B 1 2.44–3.66 5.18 86.49 4.82 3.51 7.41 0.063 0.026 0.237 --

B 1 3.66–4.88 41.83 50.08 6.27 1.82 13.25 .035 .037 .662 --

B 1 5.79–6.10 4.17 30.78 53.15 11.9 17.06 .359 .147 .783 --

B 2 3.35–3.51 35.35 55.01 7.89 1.75 8.58 .186 .022 .286 --

B 2 3.51–3.66 47.94 27.16 20.22 4.68 6.98 .558 .181 .577 --

B 2 3.66–3.96 8.6 35.75 41.31 14.34 15.56 .294 .179 .934 --

B 2 5.79–6.10 4.75 89.63 3.89 1.72 3.79 .035 .029 .153 --

B 2 7.01–7.32 1.44 92.27 4.59 1.7 2.25 .024 .029 .17 --

B 3 2.44–2.59 20.77 73.89 4.48 .86 5.49 .044 .019 .17 --

B 3 3.66–3.81 47.26 46.24 6.5 .5 10.36 .02 .011 .144 --

B 3 6.10–6.71 40.4 54.31 4.44 .84 9 .018 .014 .211 --

B 4 2.44–2.74 26.96 68.86 4.17 .5 2.65 .051 .0015 .113 --

B 4 4.57–4.88 .62 92.41 2.56 4.41 8.47 .04 .0015 .221 --

B 4 7.01–7.32 1.31 92.8 3.26 2.63 10.2 .058 .118 .445 --

B 5 2.13–2.44 .78 16.41 70.94 11.88 8.93 2.064 .0015 .586 --

B 5 2.44–3.66 50.2 39.78 10.02 .5 5.89 .057 .0015 .131 --

B 5 3.66–4.88 60.61 36.33 3.05 .5 12.36 .05 .0015 .061 --

B 5 5.49–6.10 17.46 82.54 0 .5 9.96 .01 .0015 .128 --

B 5 6.10–6.86 27.91 70.03 0 2.05 10.16 .055 .061 .335 --

B 6 2.13–2.44 4.65 77.52 15.69 2.13 1.74 .215 .01 .149 --

B 6 2.44–3.66 27.21 60.81 11.98 .5 7.15 .079 .007 .167 --

B 6 3.66–4.88 41.89 50.27 7.84 .5 10.03 .01 .002 .149 --

B 6 4.88–5.18 13.91 81.03 5.06 .5 9.34 .01 .006 .132 --

B 6 6.71–7.32 20 72.39 4.89 2.73 10.14 .02 .006 .144 --

B 6.1 2.44–3.05 33.6 52.41 10.53 3.45 6.43 .127 .016 .16 < 0.01

B 6.1 3.05–3.66 43.8 42.77 7.88 5.57 14.11 .117 .012 .129 < .01

B 6.1 3.66–4.27 21.32 70.35 4.51 3.81 12.19 .01 .015 .131 < .01

B 6.1 4.27–4.88 16.92 78.63 1.92 2.52 10.22 .01 .019 .141 < .01

B 6.1 4.88–5.33 42.04 49.9 4.79 3.27 10.9 .01 .012 .132 < .01

B 6.1 5.33–5.79 29.28 63.12 4.6 2.99 9.19 .01 .016 .113 < .01

B 7 2.13–2.44 1.21 95.52 3.28 .5 1.99 .026 .003 .082 -- 

B 7 2.44–3.66 1.6 92.12 6.29 .5 2.18 .223 .008 .199 -- 

B 7 4.88–5.18 13.11 80.46 6.43 .5 8.3 .021 .114 .256 -- 

B 7 7.01–7.32 38.44 56 3.76 1.79 9.11 .01 .002 .139 -- 

B 8 2.13–2.44 .46 73.5 19.2 6.85 3.88 .204 .008 .135 -- 

B 8 3.05–3.66 47.12 44.75 7.1 1.03 7.51 .045 .003 .108 -- 

B 8 3.66–4.27 44.14 47.87 3.83 4.14 10.11 .068 .057 .262 -- 

B 8 5.79–6.10 18.11 75.46 2.14 4.29 9.83 .048 .06 .298 -- 

B 8 6.10–6.40 15.21 80.85 0.74 3.19 3.22 .032 .022 .155 -- 

B 8 7.01–7.32 37.41 54.8 4.17 3.62 10.08 .05 .054 .304 -- 

B 9 2.13–2.44 0.37 87.07 11.62 .93 2.1 .121 .004 .093 -- 

B 9 3.35–3.66 39.84 49.14 10.16 .87 7.67 .167 .083 .319 -- 

B 9 4.57–4.88 0 84.99 13.17 1.84 9.38 .142 .126 .65 < .01

B 9 5.79–6.10 32.67 62.76 4.56 .5 8.26 .041 .043 .383 < .01

B 9 6.10–6.40 45.56 46.78 5.96 1.71 7.02 .04 .021 .132 < .01

B 10 2.13–2.44 2.97 79.06 11.47 6.49 3.2 .032 .003 .05 < .01

B 10 3.05–3.66 38.91 47.78 8.99 4.31 15.15 .01 .004 .156 < .01

B 10 4.57–4.88 29 50.69 14.23 6.09 18.06 .71 .004 .181 < .01

B 10 5.79–6.10 17.1 78.1 1.18 3.64 8.48 .023 .012 .127 < .01

B 10 7.01–7.32 30.25 59.97 5.3 4.48 18.2 .132 .013 .178 < .01
Appendix 1. Supplemental Tables 9

Table 1–2. Texture analysis of the sediment samples with the sand fraction sub-divided into 

coarse, medium, and fine sand.

[Analyses values are in percent; <, less than]

Samples Texture analysis

Borehole 

no.

Depth

(meters) Gravel

Sand

Silt Clay Coarse Medium Fine Total

B 1 2.44–3.66 5.18 42.63 30.53 13.33 86.49 4.82 3.51

B 1 3.66–4.88 41.83 35.83 7.75 6.5 50.08 6.27 1.82

B 1 5.79–6.10 4.17 7.4 6.29 17.09 30.78 53.15 11.9

B 2 3.35–3.51 35.35 38.16 7.81 9.04 55.01 7.89 1.75

B 2 3.51–3.66 47.94 12.08 4.59 10.49 27.16 20.22 4.68

B 2 3.66–3.96 8.6 11.11 9.77 14.87 35.75 41.31 14.34

B 2 5.79–6.10 4.75 26.34 39.72 23.57 89.63 3.89 1.72

B 2 7.01–7.32 1.44 6.72 35.29 50.26 92.27 4.59 1.7

B 3 2.44–2.59 20.77 33.81 32.7 7.38 73.89 4.48 .86

B 3 3.66–3.81 47.26 29.13 13.38 3.73 46.24 6.5 < 1

B 3 6.10–6.71 40.4 27.41 19.82 7.08 54.31 4.44 .84

B 4 2.44–2.74 26.96 10.88 25.6 32.38 68.86 4.17 .5

B 4 4.57–4.88 .62 22.75 49.38 20.28 92.41 2.56 4.41

B 4 7.01–7.32 1.31 21.56 51 20.24 92.8 3.26 2.63

B 5 2.13–2.44 .78 3.91 3.59 8.91 16.41 70.94 11.88

B 5 2.44–3.66 50.2 19.7 12.8 7.28 39.78 10.02 .5

B 5 3.66–4.88 60.61 24.85 6.25 5.23 36.33 3.05 .5

B 5 5.49–6.10 17.46 50 24.44 8.1 82.54 0 .5

B 5 6.10–6.86 27.91 51.47 15.62 2.94 70.03 0 2.05

B 6 2.13–2.44 4.65 7.71 30.05 39.76 77.52 15.69 2.13

B 6 2.44–3.66 27.21 22.79 23.57 14.45 60.81 11.98 .5

B 6 3.66–4.88 41.89 27.79 16.76 5.72 50.27 7.84 .5

B 6 4.88–5.18 13.91 31.72 41.61 7.7 81.03 5.06 .5

B 6 6.71–7.32 20 25.23 23.75 23.41 72.39 4.89 2.73

B 6.1 2.44–3.05 33.6 23.96 16.81 11.64 52.41 10.53 3.45

B 6.1 3.05–3.66 43.8 29.13 8.35 5.29 42.77 7.88 5.57

B 6.1 3.66–4.27 21.32 42.36 23.13 4.86 70.35 4.51 3.81

B 6.1 4.27–4.88 16.92 38.47 35.28 4.88 78.63 1.92 2.52

B 6.1 4.88–5.33 42.04 26.58 14.4 8.92 49.9 4.79 3.27

B 6.1 5.33–5.79 29.28 22.26 17.25 23.61 63.12 4.6 2.99

B 7 2.13–2.44 1.21 22.01 51.94 21.57 95.52 3.28 .5

B 7 2.44–3.66 1.6 19.61 47.2 25.31 92.12 6.29 .5

B 7 4.88–5.18 13.11 22.75 47.51 10.2 80.46 6.43 .5

B 7 7.01–7.32 38.44 27.69 20.25 8.06 56 3.76 1.79

B 8 2.13–2.44 .46 21.57 25.22 26.71 73.5 19.2 6.85

B 8 3.05–3.66 47.12 20.02 16.83 7.9 44.75 7.1 1.03

B 8 3.66–4.27 44.14 30.57 11.81 5.49 47.87 3.83 4.14

B 8 5.79–6.10 18.11 46.2 22.29 6.97 75.46 2.14 4.29

B 8 6.10–6.40 15.21 30.53 38.72 11.6 80.85 .74 3.19

B 8 7.01–7.32 37.41 37.77 12.14 4.89 54.8 4.17 3.62

B 9 2.13–2.44 .37 4.2 28.68 54.19 87.07 11.62 .93

B 9 3.35–3.66 39.84 22.92 13.11 13.11 49.14 10.16 .87

B 9 4.57–4.88 0 0.09 4.97 79.93 84.99 13.17 1.84

B 9 5.79–6.10 32.67 32.76 17.18 12.82 62.76 4.56 .5

B 9 6.10–6.40 45.56 16.87 15.27 14.64 46.78 5.96 1.71

B 10 2.13–2.44 2.97 4.36 22.55 52.15 79.06 11.47 6.49

B 10 3.05–3.66 38.91 27.17 12.59 8.02 47.78 8.99 4.31

B 10 4.57–4.88 29 32.31 10.8 7.58 50.69 14.23 6.09

B 10 5.79–6.10 17.1 29.73 36.64 11.73 78.1 1.18 3.64

B 10 7.01–7.32 30.25 41.35 13.16 5.46 59.97 5.3 4.48
10 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Table 1–3. Munsell soil color for the sediment samples at the 

study site.

Samples Munsell soil color

(moist sample)

Borehole 

no.

Depth

(meters) Notation Color

B 1 2.44–3.66 2.5Y 3/2 very dark grayish brown

B 1 3.66–4.88 5Y 4/2 olive gray

B 1 5.79–6.10 1 GLEY 2.5/N black

B 2 3.35–3.51 5YR 5/6 yellowish red

B 2 3.51–3.66 1 GLEY 2.5/N black

B 2 3.66–3.96 1 GLEY 3/10Y dark greenish gray

B 2 5.79–6.10 1 GLEY 5/10Y greenish gray

B 2 7.01–7.32 1 GLEY 3/10Y dark greenish gray

B 3 2.44–2.59 7.5 YR 5/2 brown

B 3 3.66–3.81 7.5 YR 6/6 reddish yellow

B 3 6.10–6.71 7.5 YR 6/4 light brown

B 4 2.44–2.74 7.5 YR 3/2 dark brown

B 4 4.57–4.88 5 YR 5/3 reddish brown

B 4 7.01–7.32 1 GLEY 3/10GY dark greenish gray

B 5 2.13–2.44 2.5Y 2.5/1 black

B 5 2.44–3.66 10R 3/4 dusky red

B 5 3.66–4.88 10YR 5/6 yellowish brown

B 5 5.49–6.10 5YR 4/4 reddish brown

B 5 6.10–6.86 1 GLEY 4/1 dark greenish gray

B 6 2.13–2.44 5 YR 2.5/2 dark reddish brown

B 6 2.44–3.66 2.5 Y 5/4 light olive brown

B 6 3.66–4.88 2.5 Y6/3 light yellowish brown

B 6 4.88–5.18 2.5 Y6/4 light yellowish brown

B 6 6.71–7.32 2.5 Y6/3 light yellowish brown

B 6.1 2.44–3.05 1 GLEY 2.5/10Y greenish black

B 6.1 3.05–3.66 10 YR 5/2 grayish brown

B 6.1 3.66–4.27 10 R 6/3 pale red

B 6.1 4.27–4.88 10 R 6/6 light red

B 6.1 4.88–5.33 2.5 YR 3/2 dark reddish brown

B 6.1 5.33–5.79 10 R 6/6 light red

B 7 2.13–2.44 5YR 5/4 reddish brown

B 7 2.44–3.66 2.5 Y 3/2 very dark grayish brown

B 7 4.88–5.18 7.5 YR 6/3 light brown 

B 7 7.01–7.32 2.5 Y 5/4 light olive brown

B 8 2.13–2.44 10 R 2.5/1 reddish black

B 8 3.05–3.66 5 YR 4/3 reddish brown

B 8 3.66–4.27 1 GLEY 6/1 greenish gray

B 8 5.79–6.10 1 GLEY 6/5GY greenish gray

B 8 6.10–6.40 5 YR 5/4 reddish brown

B 8 7.01–7.32 1 GLEY 4/5GY dark grayish gray

B 9 2.13–2.44 2.5 YR 3/2 dusky red

B 9 3.35–3.66 10 YR 4/2 dark grayish brown

B 9 4.57–4.88 1 GLEY 4/10GY dark grayish gray

B 9 5.79–6.10 1 GLEY 5/5GY greenish gray

B 9 6.10–6.40 2.5 YR 6/3 light reddish brown

B 10 2.13–2.44 2.5 YR 3/3 dark reddish brown

B 10 3.05–3.66 10 YR 7/6 yellow

B 10 4.57–4.88 5 Y 7/3 pale yellow

B 10 5.79–6.10 5 YR 5/4 reddish brown

B 10 7.01–7.32 2.5 Y 6/3 light yellowish brown
Appendix 1. Supplemental Tables 11

Table 1–4. Organic and inorganic carbon concentrations 

of the individual sediment samples.

[IC-CO3

2-, inorganic carbon as carbonates; <, less than]

Samples

IC-CO3

2-

(percent)

Organic carbon 

(percent) Borehole

no.

Depth

(meters) Run 1 Run 2

B 1 2.44–3.66 7.405 0.068 0.059

B 1 3.66–4.88 13.251 .037 .032

B 1 5.79–6.10 17.058 .348 .369

B 2 3.35–3.51 8.579 .188 .184

B 2 3.51–3.66 6.976 .588 .528

B 2 3.66–3.96 15.556 .299 .29

B 2 5.79–6.10 3.791 .045 .026

B 2 7.01–7.32 2.247 .017 .03

B 3 2.44–2.59 5.491 .042 .046

B 3 3.66–3.81 10.361 .018 < .020

B 3 6.10–6.71 9.004 .019 .017

B 4 2.44–2.74 2.654 .054 .049

B 4 4.57–4.88 8.467 .05 .031

B 4 7.01–7.32 10.205 .065 .051

B 5 2.13–2.44 8.931 2.091 2.037

B 5 2.44–3.66 5.885 .054 .06

B 5 3.66–4.88 12.363 .048 < .020

B 5 5.49–6.10 9.965 < .020 < .020

B 5 6.10–6.86 10.163 .045 .065

B 6 2.13–2.44 1.745 .216 .214

B 6 2.44–3.66 7.146 .071 .087

B 6 3.66–4.88 10.034 < .020 < .020

B 6 4.88–5.18 9.343 < .020 < .020

B 6 6.71–7.32 10.137 < .020 .022

B 6.1 2.44–3.05 6.427 .126 .128

B 6.1 3.05–3.66 14.111 .125 .109

B 6.1 3.66–4.27 12.194 < .020 < .020

B 6.1 4.27–4.88 10.218 < .020 < .020

B 6.1 4.88–5.33 10.896 < .020 < .020

B 6.1 5.33–5.79 9.19 < .020 .012

B 7 2.13–2.44 1.986 .029 .022

B 7 2.44–3.66 2.176 .216 .231

B 7 4.88–5.18 8.302 .022 .019

B 7 7.01–7.32 9.109 .012 .012

B 8 2.13–2.44 3.882 .207 .201

B 8 3.05–3.66 7.509 .038 .053

B 8 3.66–4.27 10.107 .077 .059

B 8 5.79–6.10 9.827 .046 .05

B 8 6.10–6.40 3.222 .042 .022

B 8 7.01–7.32 10.077 .045 .055

B 9 2.13–2.44 2.102 .183 .059

B 9 3.35–3.66 7.666 .179 .156

B 9 4.57–4.88 9.38 .13 .153

B 9 5.79–6.10 8.26 .042 .039

B 9 6.10–6.40 7.024 .006 .035

B 10 2.13–2.44 3.202 .048 .016

B 10 3.05–3.66 15.148 .007 < .020

B 10 4.57–4.88 18.058 .697 .722

B 10 5.79–6.10 8.483 .024 .022

B 10 7.01–7.32 18.205 .146 .117
12 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Table 1–5. Inorganic sulfur concentrations for the 

sediment samples from the study site.

[<, less than; --, not determined]

Samples Inorganic sulfur 

(percent)

Borehole

no.

Depth 

(meters) Run 1 Run 2

B 1 2.44–3.66 0.026 0.026

B 1 3.66–4.88 .06 --

B 1 5.79–6.10 .089 --

B 2 3.35–3.51 .033 --

B 2 3.51–3.66 .224 --

B 2 3.66–3.96 .102 --

B 2 5.79–6.10 .027 --

B 2 7.01–7.32 .028 --

B 3 2.44–2.59 .024 --

B 3 3.66–3.81 .016 --

B 3 6.10–6.71 .012 --

B 4 2.44–2.74 < .003 < .003

B 4 4.57–4.88 < .003 --

B 4 7.01–7.32 .119 --

B 5 2.13–2.44 < .003 --

B 5 2.44–3.66 < .003 --

B 5 3.66–4.88 < .003 --

B 5 5.49–6.10 < .003 --

B 5 6.10–6.86 .07 --

B 6 2.13–2.44 .007 .01

B 6 2.44–3.66 .01 --

B 6 3.66–4.88 .002 --

B 6 4.88–5.18 .004 --

B 6 6.71–7.32 .007 --

B 6.1 2.44–3.05 .017 --

B 6.1 3.05–3.66 .015 --

B 6.1 3.66–4.27 .011 --

B 6.1 4.27–4.88 .018 --

B 6.1 4.88–5.33 .017 --

B 6.1 5.33–5.79 .013 --

B 7 2.13–2.44 .002 --

B 7 2.44–3.66 .008 --

B 7 4.88–5.18 .129 --

B 7 7.01–7.32 .003 --

B 8 2.13–2.44 .005 --

B 8 3.05–3.66 .005 --

B 8 3.66–4.27 .054 --

B 8 5.79–6.10 .041 --

B 8 6.10–6.40 .021 --

B 8 7.01–7.32 .074 --

B 9 2.13–2.44 .003 --

B 9 3.35–3.66 .137 --

B 9 4.57–4.88 .076 --

B 9 5.79–6.10 .063 --

B 9 6.10–6.40 .026 --

B 10 2.13–2.44 .002 --

B 10 3.05–3.66 .006 --

B 10 4.57–4.88 .003 --

B 10 5.79–6.10 .011 --

B 10 7.01–7.32 .015 --
Appendix 1. Supplemental Tables 13

Table 1–6. Ferrous iron concentrations for the sediment 

samples from the study site.

[Fe(II)< ferrous iron; --, not determined]

Samples Fe(II) (percent)

Borehole

no.

Depth 

(meters)

Non-pyritic Pyrite

Fe(II) Run 1 Run 2 Average

B 1 2.44–3.66 0.214 -- 0.214 0.023

B 1 3.66–4.88 .63 0.626 .628 .034

B 1 5.79–6.10 .655 -- .655 .128

B 2 3.35–3.51 .267 -- .267 .019

B 2 3.51–3.66 .42 -- .42 .157

B 2 3.66–3.96 .778 .768 .773 .161

B 2 5.79–6.10 .128 -- .128 .025

B 2 7.01–7.32 .145 -- .145 .025

B 3 2.44–2.59 .154 -- .154 .016

B 3 3.66–3.81 .135 -- .135 .009

B 3 6.10–6.71 .199 -- .199 .012

B 4 2.44–2.74 .112 -- .112 .001

B 4 4.57–4.88 .22 -- .22 .001

B 4 7.01–7.32 .341 -- .341 .104

B 5 2.13–2.44 .584 -- .584 .002

B 5 2.44–3.66 .131 -- .131 0

B 5 3.66–4.88 .061 -- .061 0

B 5 5.49–6.10 .127 -- .127 .001

B 5 6.10–6.86 .283 -- .283 .052

B 6 2.13–2.44 .141 -- .141 .008

B 6 2.44–3.66 .161 -- .161 .006

B 6 3.66–4.88 .148 -- .148 .001

B 6 4.88–5.18 .126 -- .126 .006

B 6 6.71–7.32 .138 -- .138 .006

B 6.1 2.44–3.05 .146 -- .146 .014

B 6.1 3.05–3.66 .118 -- .118 .011

B 6.1 3.66–4.27 .118 -- .118 .013

B 6.1 4.27–4.88 .125 -- .125 .018

B 6.1 4.88–5.33 .122 -- .122 .01

B 6.1 5.33–5.79 .099 -- .099 .014

B 7 2.13–2.44 .079 -- .079 .003

B 7 2.44–3.66 .192 -- .192 .007

B 7 4.88–5.18 .157 -- .157 .099

B 7 7.01–7.32 .137 -- .137 .002

B 8 2.13–2.44 .128 -- .128 .007

B 8 3.05–3.66 .106 -- .106 .002

B 8 3.66–4.27 .212 -- .212 .05

B 8 5.79–6.10 .246 -- .246 .052

B 8 6.10–6.40 .136 -- .136 .019

B 8 7.01–7.32 .257 -- .257 .047

B 9 2.13–2.44 .09 -- .09 .003

B 9 3.35–3.66 .247 -- .247 .072

B 9 4.57–4.88 .54 -- .54 .11

B 9 5.79–6.10 .346 -- .346 .037

B 9 6.10–6.40 .114 -- .114 .018

B 10 2.13–2.44 .048 .045 .046 .004

B 10 3.05–3.66 .153 -- .153 .003

B 10 4.57–4.88 .178 -- .178 .003

B 10 5.79–6.10 .116 -- .116 .011

B 10 7.01–7.32 .167 -- .167 .011
14 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

Appendix 2. Supplemental Figures
Appendix 2. Supplemental Figures 15

0

1,000

2,000 XRD scan of aquifer sediment sample C1 (2.44–3.66 meters)

0

1,000

2,000

0 10 20 30 40 50 60 70 80 

0

1,000

2,000

0 10 20 30 40 50 60 70 80 

10,208

XRD scan of aquifer sediment sample C1 (3.66–4.88 meters)

5,656 2,701

XRD scan of aquifer sediment sample C2 (3.35–3.51 meters)

5,175 2,273

XRD scan of aquifer sediment sample C2 (3.51–3.66 meters)

7,681

XRD scan of aquifer sediment sample C2 (3.66–3.96 meters)

6,286

XRD scan of aquifer sediment sample C2 (7.01–7.32 meters)

2,819 15,063

Quartz

Dolomite

Calcite

Plagioclase

Alkali feldspar

Amphibole

Clinochlore

Qz

Do

C

Pf

Af

Amp

Ccl

EXPLANATION

2-theta position

Intensity, in counts

2-theta position

Qz Qz

Qz

Qz

Qz

Qz

Qz

Qz

Do Do Qz

Do

C

Pf

Af

Af

Amp

Ccl

Pf

Qz

Qz

Qz

Qz

Qz Qz

Qz

Qz Qz

Do

Do Do

C

Pf

Af

Af

Amp

Ccl

Pf

Qz

Qz

Qz Qz

Qz

Qz

Qz

Qz

Qz

Do

Do

Do C

Pf

Af

Af

AmpCcl

Pf

Qz

Qz

QzQz

Qz

Qz

Qz

Qz

Qz

Do

Do

Do C

Pf

Af

Af

AmpCcl

Pf

Qz Qz

QzQz

Qz

Qz

Qz

Qz

Qz

Do

Do

Do

C Pf

Af

Af

AmpCcl

Pf

Qz

Qz

Qz Qz

Qz

Qz

Qz

Qz

Qz

Do

Do Do

C

Pf

Af

Af

AmpCcl

Pf

Figure 2–1. Selected x-ray diffraction (XRD) scans of aquifer sediments.
16 Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa, 2006–07

0

1,000

2,000

0

1,000

2,000

0 10 20 30 40 50 60 70 80 

0

1,000

2,000

0 10 20 30 40 50 60 70 80 

XRD scan of aquifer sediment sample C3 (3.66–3.81 meters)

4,447 3,838

XRD scan of aquifer sediment sample C3 (6.10–6.71 meters)

4,785 2,289

XRD scan of aquifer sediment sample C4 (2.44–2.74 meters)

2,711

14,637

2,241

XRD scan of aquifer sediment sample C4 (4.57–4.88 meters)

2,480 12,400

XRD scan of aquifer sediment sample C5 (6.10–6.86 meters)

12,081

Quartz

Dolomite

Calcite

Plagioclase

Alkali feldspar

Amphibole

Clinochlore

Qz

Do

C

Pf

Af

Amp

Ccl

EXPLANATION

2-theta position

Intensity, in counts

2-theta position

Qz Qz

QzQz

Qz

Qz

Qz

Qz

Qz

Do

Do Do

C

Pf

Af

Af

AmpCcl

Pf

Qz

Qz

Qz Qz

Qz Qz

Qz

Qz

Qz

Do

Do Do

C

Pf

Af

Af

AmpCcl

Pf

Qz

Qz

QzQz

Qz Qz

Qz

Qz

Qz

Do

Do

Do

C

Pf

Af

Af

AmpCcl

Pf

Qz

Qz

Qz

Qz Qz

Qz

Qz

Qz

Qz

Do Do

Do

C

Pf

Af

Af

Amp

Ccl

Pf

Qz Qz

Qz

Qz Qz

Qz

Qz

Qz

Qz

Do

Do

Do

C Pf

Af

Af

Amp

Ccl

Pf

Qz

Qz

Qz Qz

Qz

Qz

Qz

Qz

Qz

Do

Do

Do

Pf C

Af

Af

Amp

Ccl

Pf

XRD scan of aquifer sediment sample C3 (2.44–2.59 meters)

9,322

Figure 2–1. Selected x-ray diffraction (XRD) scans of aquifer sediments.—Continued
Appendix 2. Supplemental Figures 17

0 10 20 30 40 50 60 70 80 

0

1,000

2,000

0 10 20 30 40 50 60 70 80 

XRD scan of aquifer sediment sample C10 (2.13–2.44 meters)

13,587

Quartz

Dolomite

Calcite

Plagioclase

Alkali feldspar

Amphibole

Clinochlore

Qz

Do

C

Pf

Af

Amp

Ccl

EXPLANATION

2-theta position

Intensity, in counts

2-theta position

Qz

Qz

Qz

Qz

Qz

Qz

Qz

Qz

Qz

Do

Do

Do

C

Pf

Af

Af

Amp

Ccl

Pf

Qz Qz

Qz

Qz

Qz

Qz

Qz

Qz

Qz

Do

Do Do

Do

Pf

Af

Af

AmpCcl

Pf

C

XRD scan of aquifer sediment sample C9 (2.13–2.44 meters)

2,579 17,819

Figure 2–1. Selected x-ray diffraction (XRD) scans of aquifer sediments.—Continued
Publishing support provided by the Rolla Publishing Service Center.

Maharjan and others—Electron Donor Concentrations in Sediments and Sediment Properties near New Providence, Iowa—DS 737