Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

Groundwater site Surface-water site

Data Series 495

U.S. Department of the Interior U.S. Geological Survey Cover illustration:

USGS personnel collecting a water sample from a small stream in Iowa.

Modified version of figure 1 from this report.

USGS personnel collecting and processing a ground- Photographs taken by USGS personnel. water sample. Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

By Stephen J. Kalkhoff, Sarah J. Stetson, Kris D. Lund, Richard B. Wanty, and Gregory L. Linder

Data Series 495

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: 2010

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Suggested citation: Kalkhoff, S.J., Stetson, S.J., Lund, K.D., Wanty, R.B., and Linder, G.L., 2010, Perchlorate data for streams and groundwater in selected areas of the United States, 2004: U.S. Geological Survey Data Series 495, 43 p. with appendix. iii

Contents

Abstract...... 1 Introduction...... 1 Purpose and Scope...... 2 Description of the Study Area...... 2 Selection of Sampling Sites...... 2 Methods...... 3 Sample Collection Methods...... 3 Surface Water...... 3 Groundwater...... 4 Sample Processing...... 4 Analytical Methods...... 4 Quality Assurance...... 4 Field Blank Samples...... 4 Replicate Samples...... 5 Laboratory Quality Assurance Procedures...... 5 Stability of Perchlorate in Water Samples...... 5 Occurrence of Perchlorate...... 5 Acknowledgments...... 14 References...... 14 Appendix...... 41

Figure

1–9 Maps showing: 1. Location of surface-water and groundwater sites for reconnaissance sampling, 2004...... 3 2. Perchlorate concentrations at selected surface-water and groundwater sites in Arkansas and Texas, 2004...... 6 3. Perchlorate concentrations at selected surface-water sites in Arizonia and New Mexico, 2004...... 7 4. Perchlorate concentrations at selected surface-water and groundwater sites in California and Nevada, 2004...... 8 5. Perchlorate concentrations at selected surface-water and groundwater sites in Colorado, Wyoming, and South Dakota, 2004...... 9 6 Perchlorate concentrations at selected surface-water and groundwater sites in Iowa, 2004...... 10 7. Perchlorate concentrations at selected surface-water sites in Illinois, Indiana, Missouri, and Ohio, 2004...... 11 8. Perchlorate concentrations at selected surface-water sites in Michigan, Minnesota, and Wisconsin, 2004...... 12 9 Perchlorate concentrations at selected surface-water and groundwater sites in Nebraska, 2004...... 13 iv

Tables

1. Selected sites in the United States sampled for perchlorate analysis ...... 18 2. Quality assurrance-quality-control samples (field blanks) for perchlorate reconnaissance study in selected areas of the United States...... 5 3. Quality assurrance-quality-control samples (replicates) for perchlorate reconnaissance study in selected areas of the United States...... 28 4. Perchlorate concentrations at selected surface-water and groundwater sites in the United States...... 29 5. Summary of perchlorate detections and concentrations in selected States...... 40 6. Perchlorate concentrations in streams sampled twice during the reconnaissance study...... 40

Conversion Factors, Abbreviations, and Datums SI to Inch/Pound Multiply By To obtain Length centimeter (cm) 0.3937 inch (in.) millimeter (mm) 0.03937 inch (in.) meter (m) 3.281 foot (ft) kilometer (km) 0.6214 mile (mi) Volume liter (L) 33.82 ounce, fluid (fl. oz) Flow rate cubic meter per second (m3/s) 0.0353 cubic feet per second (ft3/s) Mass gram (g) 0.03527 ounce, avoirdupois (oz) Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µg/L). Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

By Stephen J. Kalkhoff, Sarah J. Stetson, Kris D. Lund, Richard B. Wanty, and Gregory L. Linder

Abstract Although perchlorate has been documented as a point- source contaminant in groundwater near areas where ammonium perchlorate is produced and where solid-fuel rockets, This report presents data collected as part of a recon- fireworks, and other explosives are manufactured or used, naissance study to evaluate the occurrence of perchlorate in recent studies (Parker and others, 2008) have found perchlo- rivers and streams and in shallow aquifers in selected areas of rate in areas with no apparent anthropogenic sources and the United States. Perchlorate, a component in rocket fuels, where agricultural activities (fertilizers and irrigation) are fireworks, and some explosives is soluble in water and persists prevalent. Small-scale studies have documented perchlorate in soils and water for long periods. It is biologically active at in groundwater in the Texas High Plains (Rajagopalan and relatively low-levels in the environment, and has been identi- others, 2006), leafy vegetables (Sanchez and others, 2005), fied as an endocrine-disrupting chemical. The purpose of this beef cattle (Cheng and others, 2004) and selected dairy milk reconnaissance was to determine the occurrence of perchlorate from supermarket shelves in Texas (Kirk and others, 2003). in agricultural areas of the Midwestern and North-Central Perchlorate occurs naturally in precipitation (Rajagopalan and United States and in arid Central and Western parts of the others, 2009) and may accumulate in the unsaturated zone in United States. areas with low precipitation (deserts) by deposition processes Samples were collected from 171 sites on rivers and similar to nitrate (Walvoord and others, 2003). Infiltration of streams and 146 sites from wells during the summer and irrigation water can mobilize accumulated perchlorate and early fall of 2004. Samples were collected from surface-water transport it from the unsaturated zone to the underlying aquifer sites in 19 states and from wells in 5 states. Perchlorate was (Scanlon and others, 2008). detected in samples collected in 15 states and was detected in The identification of perchlorate in sodium nitrate fertiliz- 34 of 182 samples from rivers and streams and in 64 of 148 ers derived from Chilean caliche (Urbansky and others, 2001a) groundwater samples at concentrations equal to or greater may support this suggestion. Although identified in Chilean than 0.4 micrograms per liter. Perchlorate concentrations were caliche, perchlorate does not generally occur in manufactured 1.0 micrograms per liter or greater in surface-water samples nitrogen fertilizers (Urbansky and others, 2001b), but some from seven states and in groundwater samples in four states. questions remain on its occurrence in potash minerals (Orris Only one surface-water and one groundwater sample had and others, 2003). Perchlorate in groundwater in the United concentrations greater than 5.0 micrograms per liter. Perchlo- States has been documented by the U.S. Environmental Pro- rate concentrations in followup samples collected from 1 to 3 tection Agency (2003), but the areal occurrence has not been months after the initial sample were unchanged at four of five investigated. stream sites. Perchlorate is soluble in water and persists in soils and water for long periods. It is biologically active at relatively low-levels in the environment, and its role as an endocrine- Introduction disrupting chemical has been documented in some fish (Patino and others, 2003; Crane and others, 2005). Uptake by plants - Perchlorate (ClO4 ), a naturally occurring and manmade (Nzengung and others, 1999) and microbial degradation (Cole- compound that is a component in rocket fuels, fireworks, and man and others, 2003; Sturchio and others, 2003) also has some explosives, has been detected in many water supplies been established. The U.S. Environmental Protection Agency throughout the country. Most documented occurrences of established a chronic oral reference dose (RfD) for humans perchlorate have been related to military and chemical-manu- of 0.0007 milligrams per kilogram body weight per day. The facturing operations. However, a number of studies have docu- RfD equates to a Drinking Water Equivalent Level (DWEL) mented the presence of perchlorate in nitrate-bearing minerals of 24.5 micrograms per liter (μg/L), or approximately equal to from Chile that have been or are still being used as fertilizers parts per billion (ppb). A DWEL is a lifetime exposure concen- in the United States. tration protective of adverse, noncancer health effects that assumes all of the exposure to a contaminant is from drinking 2 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 water. (U.S. Environmental Protection Agency, 2008). A num- Description of the Study Area ber of states have set advisory levels less than the DWEL and as low as 1.0 μg/L (Interstate Technology Regulatory Council, The reconnaissance study was concentrated in the Central 2005). and Southwestern part of the United States (fig. 1). Perchlorate The occurrence of perchlorate has been documented in samples were based on the availability of wells and streams groundwater at pristine areas across the United State (Parker being sampled as part of other U.S. Geological Survey’s and others, 2008) and has been extensively studied in ground- (USGS) programs. The ongoing USGS water-quality programs water in the southern High Plains in Texas and New Mexico include the National Water-Quality Assessment Program (Rajagopalan and others, 2006), Southwestern United States (NAWQA): joint US Environmental Protection Agency (EPA) (Balaji and others, 2007), and California. However, additional and USGS Landscape Indicators (EPALIPS) project; and sev- information on the occurrence of perchlorate in the Central eral USGS/State cooperative studies. Because of the integrated and Midwestern United States is still needed. Research has design, an extensive set of water-chemistry data that include centered mainly on the occurrence in groundwater, and the physical properties, major ions, nutrients, and in some cases, occurrence of perchlorate in streams and rivers has not been trace elements are available in addition to the perchlorate data investigated extensively. presented in this report. A list of projects that provided assis- tance in sample collection and selected reports documenting Purpose and Scope their findings is provided in appendix 1. A reconnaissance sampling was conducted in 2004 to: (1) Selection of Sampling Sites collect data to determine the occurrence of perchlorate over a gradient of agricultural land-use intensity in areas of the Mid- Several criteria were used to select stream and river sites western and North Central United States and (2) collect data and wells where perchlorate samples were added to existing to determine if varying annual precipitation across the middle data collection efforts to determine if perchlorate contamina- and western parts of the United States affects the occurrence tion is more prevalent in areas where nitrogen and potassium of perchlorate in rivers and streams. minerals are used as fertilizers for agriculture and to determine Surface-water and groundwater data were collected in if perchlorate contamination is more prevalent in areas that agricultural areas. Surface-water data were collected at sites receive less rainfall where perchlorate may not be readily on small third-order streams draining agricultural watersheds flushed through the hydrologic system. in the Midwestern corn belt in the fall of 2004 during low- Surface-water and groundwater sites were selected to flow periods when most water in the stream originates from obtain data on the occurrence of perchlorate in agricultural groundwater discharge. Followup samples were collected areas (table 1, at the back of this report). Surface-water sites from five streams 1 to 3 months after the initial sampling to on medium to large streams and rivers that drain agricul- document any seasonal variability. Groundwater data were tural, urban, and undisturbed watersheds from Texas through collected from shallow aquifers in the summer and early fall of Arizona, New Mexico, and California (fig. 1) were sampled to 2004 that have relatively “young” waters that may be suscep- obtain data on the occurrence of perchlorate in streams in rela- tible to contamination from current land-use practices. tion to a range of annual rainfall. Surface-water data were collected in the summer and Water samples were collected from groundwater in an early fall of 2004 from streams and rivers in the Central and area with a gradient of agricultural intensity and of fertilizer Southwestern United States to determine if varying annual use from Minnesota and Iowa southwest to Colorado. Shal- rainfall influenced perchlorate occurrence in surface water. low groundwater that has most likely infiltrated within the Sites were located on small to medium-sized streams that last 50 years was sampled to define perchlorate occurrence in drained a watershed with a single primary land use and larger aquifers. An extensive set of wells (table 1, at the back of this rivers that integrated multiple land use in the watershed. report) was sampled in Nebraska for perchlorate along with The purpose of this report is to present data collected as the standard suite of other water-quality constituents. Thirty- part of the perchlorate occurrence study in the Central and eight municipal supply wells were sampled in Iowa during Southwestern United States. Data includes those from the agri- the summer of 2004. These 38 wells occur in shallow alluvial cultural land-use gradient component and from the precipita- deposits and were selected because the aquifer is susceptible tion gradient component of the reconnaissance study. Inter- to contamination from land-surface activities. Although these pretation of the relations between perchlorate occurrence and are municipal wells, the wells are located in or near farmland. geologic, climatologic, and anthropogenic factors is beyond Additional wells were sampled in Colorado where agricultural the scope of this report. land-use intensity is minimal. Small third-order streams that drain primarily agricultural areas in the Midwestern corn- belt were selected to determine if groundwater flowing to streams contained perchlorate. One hundred and ten sites in 10 Midwestern corn-belt states were sampled. Additional sites Methods 3

120° 110° 100° 90° 80° 70°

45°

40°

35°

30°

25°

Base from U.S. Geological Survey 0 200 400 600 MILES digital data, 1:200,000, 2005, Albers Equal-Area Conic projection EXPLANATION 0 200 400 600 KILOMETERS Groundwater site Surface-water site

Figure 1. Location of surface-water and groundwater sites for reconnaissance sampling, 2004. at the mouth of agricultural and undisturbed watersheds were from the aquifer was collected. Once the sample was obtained, sampled in Minnesota, Iowa, Nebraska, and Colorado during appropriate filtration and preservation techniques were used late summer or early fall. to ensure that water quality did not change during transit to In addition to the perchlorate data presented in this report, the laboratory. Detailed sampling techniques are provided in major ion, nutrient, pesticide, and, in some cases, trace ele- the USGS National Field Manual for the collection of water- ment data for these sites are available online from the USGS quality data (U.S. Geological Survey, 1998) and are briefly NWISweb (http://waterdata.usgs.gov/nwis/) and NAWQA summarized in the following sections. data warehouse (http://infotrek.er.usgs.gov/traverse/f?p=NAW All equipment used to collect and process perchlorate QA:HOME:927964592963779). samples were precleaned with a 0.1-percent nonphosphate detergent, rinsed with tap water, and then rinsed with deionized water. Once cleaned, equipment was air dried, wrapped in aluminum foil or in plastic bags, and stored in a dust-free Methods environment to ensure clean equipment for the next sample. Detailed cleaning procedures for equipment are described by Sample Collection Methods Wilde (2004).

Perchlorate samples were collected using methods that ensured representative surface-water and groundwater sam- Surface Water ples. For rivers and streams this means that any water-quality Samples from flowing streams were collected using variability with depth or variability across the river was depth-integrating sampling methods, described in detail by integrated into the sample. For groundwater this means that Webb and others (1999), to obtain a representative sample. A stagnant water in the well casing was removed before water 4 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 brief summary follows. Collection of depth-integrated samples of 0.25 milliliters per minute (mL/min). A 50-microliter injec- involves using an equal-width-increment (EWI) or equal- tion loop was used for samples with concentrations greater discharge-increment (EDI) sampling method. The EWI or than 10 μg/L, and 1,000 microliter injection loop used for EDI methods produce a composite sample that represents the lower concentrations (less than or equal to 1 μg/L). A mem- discharge weighted concentrations of the stream cross sec- brane suppression unit in the recycle mode was used with a tion being sampled. Samples were collected at verticals from current of 50 milliamps. Samples were pretreated with the increments of the cross section of a stream having a specified barium, silver, and hydrogen cartridges. With the 2-millime- width. The number of verticals sampled varies based on the ter column system, the signal to noise ratio at 0.2 μg/L was width of the stream. Generally 10–15 vertical samples were approximately 5. composited at each site. However, in narrow streams where it was not practical to obtain multiple vertical samples, one vertical sample was collected. Occasionally, low-flow conditions (stream depth less than about 15 cm deep, or the stream Quality Assurance velocity is less than about 0.45 m/s) rendered the use of an iso- kinetic sampler impractical. In these conditions, a dip sample An extensive array of quality-assurance (QA) samples was collected. were analyzed to ensure that results were representative of those in the environment and were not because of introduction of perchlorate during equipment cleaning or from cross Groundwater contamination from previous samples (field blank samples). QA samples also were analyzed to ensure that the analytical Detailed groundwater sampling protocol is provided in method can determine accurate concentrations and can reliably the groundwater sampling section (Chapter 4–2, by Gibbs reproduce results (replicate samples). In addition to the stan- and Wilde, 1999) of the National Field Manual and in a report dard QA samples, perchlorate concentrations were measured documenting NAWQA protocols (Koterba and others, 1995). in prepared solutions for more than 600 days to document the Initially, a water-level measurement was made to document long-term stability of perchlorate in samples. natural or anthropogenic stresses on the aquifer. Wells were pumped for a sufficient amount of time so that a minimum of three well volumes were removed and so that temperature, Field Blank Samples specific conductance, and pH of the discharged water were stable. Once purged, the well was sampled by pumping the Field blank samples (blank samples) were collected to water through a 0.45 μm capsule filter into a polyethylene measure contamination introduced by the site environment bottle as described below. (atmosphere) and by sample handling, processing, and analysis. Generally, blank samples were collected routinely during the collection period of environmental water samples and were Sample Processing distributed among sites to assess a broad range of locations, hydrologic conditions, and water types. Blank samples were Water collected from wells and streams was filtered collected, processed, and analyzed in a manner that simulates through a capsule filter with a pore size of 0.45 μm for the the collection, processing, transport, and analysis of environ- perchlorate sample after filtering for major ions, nutrients, mental water samples through clean sampling and processing alkalinity, radiochemicals, and stable isotopes sample was equipment. The collection and processing of surface-water completed. This ensured that several hundred milliliters of samples were simulated by pouring blank water (pesticide- ambient water had been flushed through the filter before water grade water suitable for use in the collection of field blanks) was collected for the perchlorate sample. In addition, the first into the sampler bottle, capping the sampler bottle and nozzle 20–25 mL of filtrate was used to rinse the polyethylene sample assembly, shaking, and pouring the blank water into a split- bottle to remove any foreign material. The sample bottle then ter. Blank water from the splitter then was filtered into sample was filled, capped securely, put in a ziplock bag, and chilled bottles. Blank samples from surface-water sites were colon ice for shipment to the laboratory. Once collected, the lected prior to the collection of environmental water samples sample is kept chilled until analyzed at the laboratory. to determine if cleaning procedures removed contamination introduced by water at the previous site, and if contamination Analytical Methods was introduced by the transport of equipment to the current site. No field blank samples contained detectable concentra- The perchlorate analysis procedure was modified from tions of perchlorate (table 2). that of Wagner and others (2004). Samples were analyzed for perchlorate using a Dionex DX-500 Ion Chromaograph (IC) system with a GP40 pump and ED40 electrochemical detector, 2 millimeter AG16 guard and AS16 analytical columns, and 35 millimole potassium hydroxide eluent flowing at a flow rate Occurrence of Perchlorate 5

Table 2. Quality-assurrance-quality-control samples (field blanks) for perchlorate reconnaissance study in selected areas of the United States. [<, less than] Map identifica- Sample date Perchlorate Sample time tion number Site number Site name (month/day/ concentration (24 hour) (figures 2–9) year) (μg/L ) IA-01 05387313 Unknown Tributary to Beaver Creek 10/26/2004 1320 <0.4 near Lime Springs, IA MN-02 05316983 County Ditch 24 near Clements, MN 10/07/2004 0900 < .4 NV-01 094196783 Las Vegas Wash below Flamingo Wash 08/17/2004 1020 < .4 Confluence near Las Vegas, NV OH-12 405251082164801 Jerome Fork near Ashland, OH 10/01/2004 1008 < .4 SD-01 431559096350100 Little Beaver Creek near Canton, SD 09/02/2004 0830 < .4

Replicate Samples changes in perchlorate concentrations from the time of sample collection until sample analysis. Sets of samples containing Replicate samples were collected and analyzed to esti- 1,000, 100, 10, 1, 0.5 and 0 μg/L perchlorate in deionized mate the precision of concentration values from sample pro- water and also in local tap water were formulated. These cessing and analysis. Each replicate is an aliquot of the native samples were analyzed by ion chromatography and were sample water processed in the field through the same sample compared to perchlorate concentration in freshly prepared equipment and processed using identical procedures. Labo- standards every 24 hours for the first 7 days, biweekly for the ratory replicates are an aliquot of an environmental sample next 4 weeks, and periodically after that for a total of 400 or submitted for analysis. 610 days for the two lowest concentrations and a total of 428 Most of the replicate samples (table 3, at the back of this or 638 days for the high concentrations (Stetson and others, report) did not contain detectable concentrations of perchlo- 2006). Perchlorate was found to be stable allowing for holding rate. Analytical results of replicate samples from 10 sites had times of at least 90 days for surface-water samples and at least concentrations below the detection limit (0.4 μg/L) in both 300 days for groundwater samples (Stetson and others, 2006). the ambient and replicate sample. Results of replicate samples from five sites had low levels of perchlorate (0.41 to 0.96 μg/L) in the ambient sample but no detectable concentration in Occurrence of Perchlorate the replicate sample. Results from one site had a detection in the replicate but not in the ambient sample. Samples were collected from 171 sites on rivers and streams and 146 sites from wells during the summer and early Laboratory Quality Assurance Procedures fall of 2004. Samples were collected from surface-water sites in 19 states and from wells in 5 states. Approximately 10 percent of samples were analyzed in Perchlorate was detected in samples collected in 15 states duplicate to ensure that there is reproducibility among analy- and was detected in 34 of 182 samples from rivers and streams sis. Standards were analyzed between every 5–10 samples and in 64 of 148 groundwater samples at concentrations equal and a blank was analyzed approximately every 15 samples to or greater than the 0.4 micrograms per liter (μg/L) reporting to ensure accuracy of data and to verify that no carry over limit. Perchlorate concentrations were 1.0 μg/L or greater in occured between samples. The precision of the method was surface-water samples from seven states and in groundwater determined by calculating the standard deviation in the ana- samples in four states (table 5, at the back of this report). Only lyzed concentration of standard solutions of 100 and 1 μg/L. one surface water and one groundwater sample had concentra- To ensure that there was no loss or enrichment of perchlorate tions greater than 5.0 μg/L. The results of the reconnaissance during sample preparation, standards were analyzed after study, summarized by State, are shown in table 4 (at the back preparation in the same manner as samples. The recovered of this report) and illustrated in figures 2–9. concentrations were found to be within the standard deviation Perchlorate concentrations in followup samples collected of the original standards. from 1 to 3 months after the initial sample were unchanged at four of five stream sites (table 5). The perchlorate concentration decreased from 0.8 μg/L on August 23, 2004, to less than Stability of Perchlorate in Water Samples detection level on October 7, 2004, in the Little Cobb River near Beauford, Minnesota (table 5). The long-term stability of perchlorate in deionized water and in a common water matrix was determined to quantify any 6 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

105° 102° 99° 96° 93° 90°

36° AR-01 AR-03 AR-02 AR-04

O K L A H O M A A R K A N S A S

33°

TX-03 T E X A S

30° L O U I S I A N A

TX-01 TX-02

27°

Base from U.S. Geological Survey 0 100 200 MILES digital data, 1:200,000, 2005, Albers Equal-Area Conic projection EXPLANATION 0 100 200 KILOMETERS (identifier used in tables is next to symbol) Groundwater sampling site Surface-water sampling site Not detected Not detected 0.40 – 0.99 0.40 – 0.99 1.00 or greater 1.00 or greater For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 2. Perchlorate concentrations at selected surface-water and groundwater sites in Arkansas and Texas, 2004. Occurrence of Perchlorate 7

115° 112° 109° 106° 103°

37°

AZ-01

NM-08 NM-06 NM-05 NM-07

35° A R I Z O N A NM-01 NM-02

AZ-08 NM-03

NM-04 AZ-09 AZ-10 AZ-11 33° AZ-07 AZ-06 N E W M E X I C O AZ-05 AZ-03

AZ-02

31° AZ-04

Base from U.S. Geological Survey 0 50 100 150 MILES digital data, 1:200,000, 2005, EXPLANATION Albers Equal-Area Conic projection (identifier used in tables is next to symbol) 0 50 100 150 KILOMETERS Surface-water sampling site Not detected 0.40 – 0.99 1.00 or greater For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 3. Perchlorate concentrations at selected surface-water sites in Arizona and New Mexico, 2004. 8 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

125° 122° 119° 116° 113°

39°

NV-02 NV-03 N E V A D A NV-01

36° C A L I F O R N I A

NV-04

33° CA-02 CA-01 CA-03

CA-10 CA-11 CA-08 CA-09 CA-07 CA-06 CA-04 CA-05

Base from U.S. Geological Survey 0 50 100 150 MILES digital data, 1:200,000, 2005, EXPLANATION Albers Equal-Area Conic projection (identifier used in tables is next to symbol) 0 50 100 150 KILOMETERS Groundwater sampling site Surface-water sampling site Not detected Not detected 0.40 – 0.99 0.40 – 0.99 1.00 or greater 1.00 or greater

For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 4. Perchlorate concentrations at selected surface-water and groundwater sites in California and Nevada, 2004. Occurrence of Perchlorate 9

110° 106° 102° 98°

WY-02 WY-01 WY-04 SD-03 44° WY-03

S O U T H D A K O T A

W Y O M I N G SD-02 SD-01

41°

CO-30 CO-02 CO-03 CO-11 CO-29 CO-26 CO-28 CO-27 CO-24 CO-01 CO-25 CO-08 CO-23 CO-22 CO-09 CO-21 CO-20 CO-19 CO-18 CO-17 CO-04 CO-16 38° CO-05 CO-06 CO-07 CO-15 CO-14 CO-13 CO-10 CO-12 C O L O R A D O

Base from U.S. Geological Survey 0 50 100 150 MILES digital data, 1:200,000, 2005, EXPLANATION Albers Equal-Area Conic projection (identifier used in tables is next to symbol) 0 50 100 150 KILOMETERS Groundwater sampling site Surface-water sampling site Not detected Not detected 0.40 – 0.99 0.40 – 0.99 1.00 or greater 1.00 or greater For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 5. Perchlorate concentrations at selected surface-water and groundwater sites in Colorado, Wyoming, and South Dakota, 2004. 10 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

96°W 95°W 94°W 93°W 92°W 91°W 90°W

IA-26 IA-68 IA-01 IA-67 IA-02 IA-25 IA-03 IA-66 IA-07 IA-12 IA-27 IA-19 43°N IA-65 IA-05 IA-64 IA-63 IA-08 IA-62 IA-09 IA-06 IA-61 IA-04 IA-20 IA-13 IA-28 IA-21 IA-10 I O W A IA-59 IA-60 IA-11 IA-57 42°N IA-58 IA-56 IA-29 IA-55 IA-54 IA-53 IA-52 IA-22 IA-51 IA-49 IA-48 IA-45 IA-46 IA-50 IA-47 IA-14 IA-43 IA-44 IA-42 IA-16 IA-41 IA-23 IA-40 IA-39 IA-15 IA-38 IA-36 IA-37 IA-24 IA-17 41°N IA-35

IA-32 IA-34 IA-18

IA-31 IA-30 IA-33

Base from U.S. Geological Survey 0 50 100 MILES digital data, 1:200,000, 2005, EXPLANATION Albers Equal-Area Conic projection (identifier used in tables is next to symbol) 0 50 100 KILOMETERS Groundwater sampling site Surface-water sampling site Not detected Not detected 0.40 – 0.99 0.40 – 0.99 1.00 or greater 1.00 or greater For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 6. Perchlorate concentrations at selected surface-water and groundwater sites in Iowa, 2004. Occurrence of Perchlorate 11

94° 91° 88° 85° 82°

IL-15

42° IN-15 OH-13 OH-14 IN-01 IN-14 IN-13 O H I O OH-12 I L L I N O I S OH-02 I N D I A N A OH-11 OH-10 IL-01 IN-12 OH-09 IN-11 OH-08 IN-10 OH-07 MO-01 IL-14 IN-09 OH-01 IL-13 IL-02 IL-12 IN-08 40° IL-11 IN-07 OH-05 OH-06 MO-02 IN-05 IN-06 OH-04 IL-10 IN-04 IL-09 IL-08 IN-03 OH-03

IL-07 IN-02 M I S S O U R I IL-06 IL-05 IL-04

38° IL-03

36°

Figure 7. Perchlorate concentrations at selected surface-water sites in Illinois, Indiana, Missouri, and Ohio, 2004. 12 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

95° 92° 89° 86° 83°

48°

M I N N E S O T A

46° W I S C O N S I N MN-08 WI-03 WI-08 WI-01 MN-01 WI-05 WI-04 MN-07 MN-06 WI-07 WI-06 WI-02 MN-10 MN-02 MN-05 MN-09 MN-11 M I C H I G A N WI-09 44° MN-04 MN-12 WI-10 MI-07 MN-03 MN-13 WI-17 WI-16 WI-18 MI-04 MI-03 WI-11 WI-12 MI-06 MI-05 WI-13 WI-15 WI-14 MI-02

MI-01 MI-08 42°

Figure 8. Perchlorate concentrations at selected surface-water sites in Michigan, Minnesota, and Wisconsin, 2004. Occurrence of Perchlorate 13

103° 100° 97°

43°

NE-85 NE-84 NE-81 NE-83 NE-82 NE-76 NE-80 42° NE-77 NE-79 NE-78 NE-75 NE-74 NE-73 Inset C NE-72 NE-71 N E B R A S K A NE-61 NE-54 41° NE-57 NE-52 NE-56 NE-05 NE-02 NE-51 NE-53 NE-55 NE-47 Inset A NE-24 Inset B NE-03 NE-23 NE-22 NE-21 NE-16 NE-20 NE-15 NE-19 NE-18 NE-04 NE-17 NE-13 NE-14 NE-10 40° NE-12 NE-08 NE-09 NE-11 NE-06 NE-07

Base from U.S. Geological Survey 0 50 100 150 MILES digital data, 1:200,000, 2005, Albers Equal-Area Conic projection 0 50 100 150 KILOMETERS

Inset A Inset B Inset C NE-48 0 600 FEET 0 100 METERS NE-40 York NE-68 NE-69 US Hwy 34 Seward NE-49 NE-70 NE-50 NE-42 NE-41 NE-65 NE-43 US Hwy 34 NE-66 NE-38 NE-67 NE-37 NE-44

NE-33 County Rd 20 NE-36 NE-31 NE-34 NE-45 NE-62 Maple Creek NE-32 NE-35 NE-46 NE-63 NE-29 NE-30 NE-64 NE-39 NE-28 NE-25 NE-01 0 1 MILES 0 1 MILES NE-58 NE-26 NE-59 NE-27 NE-60 0 1 KILOMETERS 0 1 KILOMETERS

EXPLANATION (identifier used in tables is next to symbol) Groundwater sampling site Surface-water sampling site Not detected Not detected 0.40 – 0.99 0.40 – 0.99 1.00 or greater 1.00 or greater For sites with multiple samples, symbol corresponds to sample of first occurence

Figure 9. Perchlorate concentrations at selected surface-water and groundwater sites in Nebraska, 2004. 14 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

Acknowledgments Gibbs, Jacob, and Wilde, F.D., 1999, Chapter 4.2; Ground- water sampling: Preparations and purging methods at water- supply wells and monitoring wells sites in U.S. Geological This project was funded by the USGS Central Region Survey, 1998, National field manual for the collection of Integrated Science Project. The authors would like to thank water-quality data: U.S. Geological Survey Techniques of Janice Ward, USGS retired, who originally indentified the Water-Resources Investigations, book 9, chaps. A1–A9, need to obtain additional perchlorate data in the United States; available online at http://pubs.water.usgs.gov/twri9A. developed an initial study design; obtained funding; and brought together the multidisciplinary team to accomplish Interstate Technology Regulatory Council, 2005, Perchlo- this project. USGS National Water Quality Laboratory login rate: Overview of issues, status, and remedial options: The staff were instrumental in separating perchlorate samples from Interstate Technology and Regulatory Council Perchlorate other water-quality samples and ensuring the samples were Team, 90 p., available online at http://www.itrcweb.org/ sent to the perchlorate laboratory. Substantial support was Documents/PERC-1.pdf. provided by many USGS field personnel who voluntarily collected the samples as part of National Water-Quality Assess- Kirk, A.B., Smith, E.E., Tian, Kang, Anderson, T.A., and ment Progam (NAWQA), the joint USEPA/USGS LIPSs Dasgupta, P.K., 2003, Perchlorate in milk: Environmental study, and numerous USGS cooperative projects. Science and Technology, v., 37, no. 21, p. 4,979–4,981. Koterba, M.T., Wilde, F.D., and Lapham, W.W., 1995, Ground-water data-collection protocols and procedures for References the National Water-Quality Assessment Program: collection and documentation of water-quality samples and related Balaji, Rao, Anderson, T.A., Orris, G.J., Rainwater, K.A., data: U.S. Geological Survey Open-File Report 95–399, Rajagopalan, Srinath, Sandvig, R.M., Scanlon, B.R., Ston- 113 p. estrom, D.A., Walvoord, M. A., and Jackson, W.A., 2007, Landon, M.K., Clark, B.R., McMahon, P.B., McGuire, V.L., Widespread natural perchlorate in unsaturated zones of the and Turco, M.J., 2008, Hydrogeology, chemical character- Southwest United States: Environmental Science and Tech- istics, and transport processes in the zone of contribution nology, v. 41, no. 13, p. 4,522–4,528. of a public-supply well in York, Nebraska: U.S. Geological Cheng, Quiqiong, Perlumtter, Lisa, Smith, P.N., McMurry Survey Scientific Investigations Report 2008–5050, 149 p. S.T., Jackson, W.A., and Anderson, T.A., 2004, A study of Littin, G.R., 2004, Quality of ground water used for selected perchlorate exposure and adsorption in beef cattle: Journal municipal water supplies in Iowa, 1997–2002 water years: of Agricultural and Food Chemistry, v. 52, no. 11, U.S. Geological Survey Open-File Report 2004–1048, 36 p. p. 3,456–3,461. Mau, D.P., Stogner, R.W., Sr., and Edelmann, Patrick, 2007, Clark, M.L., and Mason, J.P., 2007, Water-quality character- Characterization of stormflows and wastewater treatment- istics for sites in the Tongue, Powder, Cheyenne, and Belle plant effluent discharges on water quality, suspended sedi- Fourche River drainage basins, Wyoming and Montana, ment, and stream morphology for Fountain and Monument water years 2001–2005, with temporal patterns of selected Creek Watersheds, Colorado, 1981–2006: U.S. Geological long-term water-quality data: U.S. Geological Survey Sci- Survey Scientific Investigations Report 2007–5104, 76 p. entific Investigations Report 2007–5146, 65 p. McMahon, Peter B., Dennehy, Kevin F., Bruce, Breton W., Coleman, M.L., Ader, Magali, Chaudhuri, Swades, and Gurdak, Jason J., and Qi, Sharon L., 2007, Water-quality Coates, J.D., 2003, Microbial isotopic fractionation of assessment of the High Plains Aquifer, 1999–2004: U.S. perchlorate chlorine: Applied and Environmental Microbiol- Geological Survey Professional Paper 1749, 136 p. ogy, v., 69, no. 8, p. 4,997–5,000. Nzengung, V.A., Wang, Chuhua, and Harvey, Greg, 1999, Crane, H.M., Pickford, D.B., Hutchinson, T.H., and Brown, Plant-mediated transformation of perchlorate into chlorine: J.A., 2005, Effects of Ammonium Perchlorate on Thyroid Environmental Science and Technology, v. 33, no. 9, Function in Developing Fathead Minnows, Pimephales p. 1,470–1,478. promelas: Environmental Health Perspectives, v. 113, no. 4, p. 396–401. Orris, G.J., Harvey, G.J., Tsui, D.T., and Eldridge, J.E., 2003, Preliminary analyses for perchlorate in selected natural Fredrick, B.S., Linard, J.I., and Carpenter, J.L., 2006, Envi- materials and their derivative products: U.S. Geological ronmental setting of Maple Creek watershed, Nebraska: Survey Open-File Report 2003–314, 6 p. U.S. Geological Survey Scientific Investigations Report 2006–5037, 22 p. References 15

Parker, D.R., Seyfferth, A.L., and Reese, B.K., 2008, Perchlo- Urbansky, E.T., Collette, T.W., Robarge, W.P., Hall, W.L., rate in groundwater: A synoptic survey of “pristine” sites in Skillen, J.M., and Kane, P.F., 2001b, Survey of fertilizers

the coterminous United States: Environmental Science and and related materials for perchlorate (ClO4) Final Report: Technology, v. 42, no. 5, p. 1,465–1,471. U.S. Environmental Protection Agency Office of Research and Development EPA/600/R-01/047, 26 p. Patino, R., Wainscott, M.R., Cruz-Li, E.I., Balakrishnan, S., McMurry, C., Blazer, V.S., and Anderson, T.A., 2003, U.S. Environmental Protection Agency, 2003, Occurrence and Effects of ammonium perchlorate on the reproductive potential sources of perchlorate released to the environment performance and thyroid follicle histology of zebrafish: as of April, 2003; available online at http://www.epa.gov/ Environmental Toxicology and Chemistry, v. 22, no. 5, fedfac/pdf/percocc0403.pdf. p. 1,115–1,121. U.S. Environmental Protection Agency, 2008, Emerging Rajagopalan, Srinath, Anderson, T.A., Fahlquist, L.S., Rain- Contaminant – Perchlorate: U.S. Environmental Protection water, K.A., Ridley, Moira, and Jackson, W.A., 2006, Wide- Agency Fact Sheet EPA 505-F-07-0, 4 p. spread presence of naturally occurring perchlorate in High Plains of Texas and New Mexico: Environmental Science U.S. Geological Survey, 1998, National field manual for the and Technology, v. 40, no. 10, p. 3,156–3,162. collection of water-quality data: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, Rajagopalan, Srinath, Anderson, T.A., Cox, S., Harvey, G., chaps. A1–A9, available online at http://pubs.water.usgs. Cheng, Q., and Jackson, W.A., 2009, Perchlorate in wet gov/twri9A. deposition across North America: Environmental Science and Technology, v. 43, p. 616–622. Wagner, H.P., Suarez, F.X., Pepich, B.V., Hautman, D.P., and Munch, D.J., 2004, Challenges encountered in extending Sanchez, C.A., Crump, K.S., Drieger, R.I., Khandaker, N.R., the sensitivity of U.S. Environmental Protection Agency and Gibbs, J.P., 2005, Perchlorate and nitrate in leafy Method 314.0 for perchlorate in drinking water: Journal of vegetables of North America: Environmental Science and Chromatography A, v. 1039, p. 97–104. Technology, v. 39. no. 24, p. 9,391–9,397. Walvoord, M.A., Phillips, F.M., Stonestrom, D.A., Evans, Scanlon, B.R., Reedy, R.C., Jackson, W.A., and Rao, Balaji, R.D., Hartsough, P.C., Newman, B.D., and Striegel, R.G., 2008, Mobilization of naturally occurring perchlorate 2003, A reservoir of nitrate beneath desert soils: Science, related to land-use change in the Southern High Plains, v. 302, p. 1,021–1,024. Texas: Environmental Science and Technology, v. 42, no. 23, p. 8,648–8,653. Webb, W.E., Radtke, D.B., and Iwatsubo, R.T., 1999, Chapter 4.1 Surface-water sampling: Collection methods at flow- Stanton, J.S., Landon, M.K., and Turco, M.J., 2007, Ground- ing-water and still-water sites in U.S. Geological Survey, water age and quality in the High Plains aquifer near 1998, National field manual for the collection of water- Seward, Nebraska, 2003–04: U.S. Geological Survey Scien- quality data: U.S. Geological Survey Techniques of Water- tific Investigations Report 2007–5088, 37 p. Resources Investigations, book 9, chaps. A1–A9, available online at http://pubs.water.usgs.gov/twri9A. Stetson, S.J., Wanty, R.B., Helsel, D.R., Kalkhoff, S.J., and Macalady, D.L., 2006, Stability of low levels of perchlo- Wilde, F.D., ed., 2004, Cleaning of equipment for water rate in drinking water and natural water samples: Analytica sampling (ver. 2.0): U.S. Geological Survey Techniques of Chimica Acta, v. 567, p. 108–113. Water-Resources Investigations, book 9, chap. A3, April, accessed February 13, 2009 at http://pubs.water.usgs.gov/ Sturchio, N.C., Hatzinger, P.B., Suh, Christy, and Heraty, twri9A3/. L.J., 2003, Chlorine isotope fractionation during microbial reduction of perchlorate: Environmental Science and Tech- Wright, M.T., Belitz, Kenneth, and Burton, C.A., 2005, Cali- nology, v. 37, no. 17, p. 3,859–3,863. fornia GAMA Program—Ground-water quality in the San Diego Drainages hydrogeologic province, California, 2004: Urbansky, E.T., Brown, S.K., Magnuson, M.L., and Kelty, U.S. Geological Survey Data Series 129, 91 p. C.A., 2001a, Perchlorate levels in samples of sodium nitrate fertilizer derived from Chilean caliche: Environmental Pol- lution, v. 112, p. 299–302.

Tables 1, 3–6 18 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw Site type NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 110 606 906 230 450 135 295 170 feet Well Well depth, in Unit Code Hydrologic 11010001 11010005 11010004 08020203 14070006 15040005 15040005 15050202 15050100 15060103 15060106 15060202 15060203 15060203 15060203 18070203 18070203 18070203 18070304 18070304 18070304 18070304 18070303 18070303 18070302 18070303 10190003 10190008 10190003 11020003 11020003 degrees Longitude, in decimal -93.356017 -93.405061 -92.214044 -90.615665 -111.588216 -109.511186 -110.220090 -110.174523 -110.976501 -110.921504 -111.576524 -112.065994 -111.638756 -111.716257 -111.663473 -117.069480 -117.300321 -117.645330 -117.077836 -116.979056 -116.920556 -117.114861 -117.303333 -116.663056 -117.376833 -116.900025 -104.999982 -104.588849 -104.562737 -104.839697 -104.670250 degrees Latitude, in decimal 36.454788 35.938903 35.991739 35.776465 36.864710 32.868397 33.185613 31.625926 33.102840 33.619495 33.552823 34.852242 34.276421 34.073092 33.808375 34.142788 34.078346 33.883349 32.657075 32.811361 32.866111 33.079944 33.245278 33.283083 33.285444 33.340034 39.742487 40.442481 40.411925 38.829437 38.601665 County Carroll Newton Stone Craighead Coconino Graham Graham Cochise Pinal Gila Maricopa Yavapai Gila Yavapai Maricopa San Bernardino San Bernardino Riverside San Diego San Diego San Diego San Diego San Diego San Diego San Diego San Diego Denver Weld Weld El Paso El Paso State Arkansas Arkansas Arkansas Arkansas Arizona Arizona Arizona Arizona Arizona Arizona Arizona Arizona Arizona Arizona Arizona California California California California California California California California California California California Colorado Colorado Colorado Colorado Colorado Site name Dam, AZ Dam, CO Yocum Creek near Oak Grove, AR Creek near Oak Grove, Yocum AR River near Boxley, Buffalo AR North Sylamore Creek near Fifty Six, 13N04E12ABB1 AZ Colorado River at Lees Ferry, AZ near Solomon, Valley Gila River at Head of Safford AZ Gila River at Calva, AZ San Pedro River at Charleston, AZ Gila River at Kelvin, AZ Salt River near Roosevelt, AZ Salt River below Stewart Mountain Dam, AZ River near Clarkdale, Verde AZ River near Childs, Verde East Creek above Horseshoe Tangle River below Verde AZ River below Bartlett Dam, Verde Ana River above Seven Oaks Dam, CA Santa Creek near San Bernardino, CA Warm Ana River below Prado Dam, CA Santa 017S002W27P002S 016S001W03E001S 015S001E18L005S 013S002W05D001S 011S004W04K005S 010S003E27D002S 010S005W26C003S 010S001E05B001S CO Cherry Creek at Denver, CO Lonetree Creek near Greeley, CO South Platte River near Kersey, Fountain Creek below 8th Street at Colorado Springs, Fountain Creek near Fountain, CO Site number 07053250 07055646 07060710 354635090365601 09380000 09448500 09466500 09471000 09474000 09498500 09502000 09504000 09507980 09508500 09510000 11049400 11060400 11074000 323925117044001 324840116584401 325157116551401 330447117065301 331443117181201 331659116394701 331707117223601 332024116535701 06713500 06753990 06754000 07103707 07106000 - Selected sites in the United States sampled for perchlorate analysis.

AZ-11 AZ-01 AZ-02 AZ-03 AZ-04 AZ-05 AZ-06 AZ-07 AZ-08 AZ-09 AZ-10 CA-11 AR-01 AR-02 AR-03 AR-04 CA-01 CA-02 CA-03 CA-04 CA-05 CA-06 CA-07 CA-08 CA-09 CA-10 CO-01 CO-02 CO-03 CO-04 CO-05 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, Tables 1, 3–6 19 sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type NA NA NA NA NA NA NA NA NA NA NA NA feet Well Well 24.85 19.85 28.56 14.4 23.5 28 54.21 58.57 49.58 27 28.63 58 18 38.65 28 47 19 12 15 depth, in Unit Code Hydrologic 11020003 11020003 14010006 14010005 14080201 13010002 13010002 13010002 13010004 14020003 14020001 10190003 10190003 10190002 14010002 10190003 14010002 14010003 10190003 14010001 10190012 10190003 10190006 10190003 10190012 07060002 07060002 07060004 07060006 07080102 07080102 degrees Longitude, in decimal -104.598056 -104.601085 -108.317864 -109.027055 -109.028889 -106.018634 -106.047804 -106.213086 -106.027444 -106.930206 -106.980392 -104.808306 -104.749972 -104.911139 -106.118983 -104.760639 -106.070667 -106.352139 -104.782278 -105.851819 -103.742211 -104.677797 -105.584168 -104.031797 -102.745694 -92.326111 -91.460278 -92.021389 -91.112500 -92.257400 -92.032845 degrees Latitude, in decimal 38.429444 38.287780 39.374701 39.132760 37.001111 37.160010 37.556392 37.646947 37.849189 38.542189 38.870086 39.369722 39.501028 39.568889 39.575483 39.628389 39.633028 39.641583 39.646306 39.991517 40.262158 40.348728 40.353873 40.370244 40.866356 43.441389 43.388889 43.225556 42.489167 42.836091 42.606513 County Pueblo Pueblo Garfield Mesa Montezuma Conejos Rio Grande Rio Grande Saguache Gunnison Gunnison Douglas Douglas Arapahoe Summit Arapahoe Summit Eagle Arapahoe Grand Morgan Weld Larimer Morgan Logan Howard Allamakee Winneshiek Dubuque Bremer Buchanan State Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Colorado Iowa Iowa Iowa Iowa Iowa Iowa Site name CO Springs, IA Fountain Creek near Pinon, CO Fountain Creek at Pueblo, CO Dry Fork at Upper Station near De Beque, CO Colorado River near Colorado-Utah State Line San Juan River at Four Corners, CO NA03400929CBB NA03800812ACA NA03900709ABB NA04200931BAD NB04900101BCB SC01408602BCC SC00806608BCD SC00606626BDD SC00506732DCA SC00507834BCB SC00506610DBD SC00507812ACB SC00508009AAC SC00506604BDD SC00107602DAC SB00305703BBA SB00506532DDB Thompson below Moraine Park near Estes Park, Big SB00505930CBA SB01004805CCC to Beaver Creek near Lime Tributary Unknown IA Silver Creek near Hanover, Bohemian Creek near Protivin, IA North Fork Maquoketa River at NE Dyersville, IA IA Tripoli, River near Wapsipinicon Unnamed Creek near Fairbank, IA Site number 07106300 07106500 09095300 09163500 09371010 370936106010501 373323106025001 373849106124501 375054106013401 383232106554700 385213106584700 392210104482901 393003104450001 393408104544001 393431106070801 393742104453801 393758106041401 393830106210600 393846104465601 395929105510300 401544103443101 402104104404501 402114105350101 402213104015501 405159102444201 05387313 05388325 05411595 05418080 05420680 05420858 - Selected sites in the United States sampled for perchlorate analysis.—Continued

IA-01 IA-02 IA-03 IA-04 IA-05 IA-06 CO-11 CO-06 CO-07 CO-08 CO-09 CO-10 CO-12 CO-13 CO-14 CO-15 CO-16 CO-17 CO-18 CO-19 CO-20 CO-21 CO-22 CO-23 CO-24 CO-25 CO-26 CO-27 CO-28 CO-29 CO-30 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, 20 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw Site type 65 33 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 76 44.5 56 53 feet Well Well depth, in Unit Code Hydrologic 07080207 07080207 07080207 07080207 07080207 07080203 07080205 07080206 07080209 07080106 07080107 07080104 07100002 07100004 07100006 07100007 07100008 07100008 10170204 10230003 10230003 10230003 10240002 10240003 10240003 10240003 10240009 10240002 10240002 10240002 degrees Longitude, in decimal -93.593611 -93.621849 -93.598333 -93.152425 -93.151944 -93.044722 -92.816667 -91.083611 -91.182094 -92.590161 -91.714332 -91.565833 -94.474167 -94.015000 -94.842222 -94.465833 -93.942727 -93.506111 -95.937500 -95.279444 -94.997222 -95.833889 -95.226111 -95.422222 -95.480267 -95.399711 -95.034980 -95.309988 -95.551666 -95.500276 degrees Latitude, in decimal 43.092222 42.759944 42.676389 42.314984 42.112500 43.103056 42.375000 41.533056 41.178086 41.480530 40.962248 40.728889 43.053611 42.475556 42.373333 41.773611 41.424157 41.018611 43.273889 43.438333 43.126667 42.389722 41.919167 40.740278 40.724166 40.755831 40.758602 40.832496 41.001942 41.018608 County Hancock Wright Wright Hardin Marshall Cerro Gordo Grundy Muscatine Louisa Mahaska Henry Lee Alto Palo Webster Calhoun Guthrie Madison Lucas Lyon Dickinson Clay Woodbury Crawford Fremont Fremont Fremont Page Page Mills Mills State Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Site name Garner, IA Garner, IA Lake near Park, IA Manilla, IA Unknown Tributary to East Branch Iowa River at Tributary Unknown Iowa River near Rowan, IA Ditch No. 5 near Galt, IA South Fork Iowa River Northeast of New Providence, South Minerva Creek at Clemons, IA Little Lime Creek near Nora Springs, IA Black Hawk Creek near Holland, IA IA Little Mosquito Creek near Moscow, IA Wapello, Iowa River at Buck Creek near New Sharon, IA Creek near Rome, IA Wolf IA to Suger Creek at La Crew, Tributary Branch West Whittemore, IA Prairie Creek near Brushy Creek near Duncombe, IA IA Yetter, Fork Camp Creek near West IA Springbrook Creek at Bagley, North Branch River at McBride, IA Brush Creek near Lucas, IA Rat Creek near Matlock, IA Fork Little Sioux River below Silver West Tributary Lost Island Outlet above Dickens, IA Anthon, IA Big Creek near Nishnabotna River near West Fork West to Tributary Fisher Creek near Shenandoah, IA 068N40W07BCAA 069N40W26BABD 069N36W19CD 070N39W27 072N41W27CDCC 072N41W24DAD Site number 05448910 05449500 05449580 05451210 05451425 05459800 05463080 05464925 05465500 05472330 05473340 05474195 05476680 05480610 05482361 05483463 05485800 05487770 06483471 06603760 06605395 06606650 06807278 06809775 404327095284801 404521095235801 404531095020502 404957095183501 410007095330501 410107095300001 - Selected sites in the United States sampled for perchlorate analysis.—Continued

IA-11 IA-07 IA-08 IA-09 IA-10 IA-12 IA-13 IA-14 IA-15 IA-16 IA-17 IA-18 IA-19 IA-20 IA-21 IA-22 IA-23 IA-24 IA-25 IA-26 IA-27 IA-28 IA-29 IA-30 IA-31 IA-32 IA-33 IA-34 IA-35 IA-36 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, Tables 1, 3–6 21 sw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type NA 60 38 50 48 43 34 42 38 44.5 52 55 47 57 36 34.5 50 22 45 37 72 74 55.8 25 44 32 47 37.5 39 67 34 feet Well Well 121 196 depth, in Unit Code Hydrologic 10240003 10240002 10230006 07080105 10240001 07100008 07100008 07100006 10240003 07100006 07080105 10230007 07080105 07080105 07080106 10240003 10240002 07100006 07100007 07080208 07080205 07100004 07100004 07080208 07060005 07080204 10230002 10170203 10170203 10230003 07060002 10230003 07120002 degrees Longitude, in decimal -95.244714 -95.423889 -95.880846 -92.656581 -95.541116 -93.482158 -94.511915 -93.724110 -95.070269 -93.998841 -93.117423 -95.760286 -93.261039 -93.249094 -92.903805 -94.878596 -95.338609 -94.220239 -94.824706 -92.300741 -91.680458 -93.940230 -93.937452 -92.995478 -90.643461 -93.231313 -96.269747 -96.563366 -96.496142 -95.196108 -91.795710 -95.533619 -87.723918 degrees Latitude, in decimal 41.021660 41.198328 41.280276 41.354727 41.469992 41.508601 41.525543 41.561656 41.628599 41.628877 41.651935 41.661934 41.673322 41.674711 41.714159 41.720820 41.825821 41.848596 41.909708 41.911663 41.996944 42.032205 42.081370 42.101931 42.527224 42.708863 42.810546 42.822493 42.994433 43.156358 43.304417 43.387190 40.630036 County Montgomery Pottawattamie Pottawattamie Mahaska Pottawattamie Warren Guthrie Polk Audubon Dallas Jasper Harrison Jasper Jasper Jasper Audubon Shelby Dallas Carroll Tama Linn Boone Boone Marshall Dubuque Franklin Plymouth Plymouth Sioux Clay Winneshiek Osceola Iroquois State Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Iowa Illinois Site name 072N38W29BA 074N40W22ADDB 075N44W22DADA 076N16W25CBDA 077N41W15ACDD 077N23W03AAAA 078N32W27ADDC 078N25W15CAAC 079N36W29BBCA 079N27W28BAAA 079N20W13ADDD 079N42W08DCCB 04510 079N21W11ABBB 079N21W01CCCA 080N18W26AADC 080N35W24CBCC 081N39W13CACB 03147 081N29W10BBBA 21882 082N34W17DDBA 082N13W13DACB 083N07W17DACD 083N27W01ABCC 084N27W13DCAA 084N18W07BCAD 089N03E18AADB 07468 091N20W05DBCC 40114 092N46W03CCAB 093N48W31CCDD 094N48W03ABDA 096N37W03DDCC 098N08W16CABD 099N40W14DCCC Sugar Creek at Milford, IL Site number 410118095144001 411154095252501 411649095525001 412117092392301 412812095322701 413031093285501 413132094304202 413342093432801 413743095041201 413744093595501 413907093070201 413943095453601 414024093153901 414029093145601 414251092541701 414315094524201 414933095201802 415055094131201 415435094492801 415442092180201 415949091404901 420156093562402 420453093561401 420607092594501 423138090383601 424312093135201 424838096161001 424921096334701 425940096294501 430923095114501 431816091474401 432314095320001 05525500 - Selected sites in the United States sampled for perchlorate analysis.—Continued

IL-01 IA-37 IA-38 IA-39 IA-40 IA-41 IA-42 IA-43 IA-44 IA-45 IA-46 IA-47 IA-48 IA-49 IA-50 IA-51 IA-52 IA-53 IA-54 IA-55 IA-56 IA-57 IA-58 IA-59 IA-60 IA-61 IA-62 IA-63 IA-64 IA-65 IA-66 IA-67 IA-68 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, 22 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw Site type NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA feet Well Well depth, in Unit Code Hydrologic 07130006 05140204 07140204 05120115 05120113 07140202 05120112 07130011 07130007 07130006 07130006 07130010 05120109 07060005 04100003 05120208 05120206 05120202 05080003 05120203 05120108 05120204 05120201 05120201 05120103 05120108 04100005 07120001 04050001 04050001 04050002 04050006 04050006 degrees Longitude, in decimal -88.588954 -88.625887 -90.050942 -88.540556 -87.778085 -89.233961 -88.278333 -90.468333 -89.435648 -88.837573 -88.484505 -90.761389 -88.102542 -90.410278 -84.801626 -86.715089 -86.002322 -86.812508 -85.099058 -87.233992 -87.085881 -85.892000 -86.290400 -85.840239 -84.858750 -87.170317 -84.919669 -87.074331 -86.050200 -86.075014 -86.216140 -84.966112 -85.113619 degrees Latitude, in decimal 40.030867 37.637549 38.286718 38.314722 38.585048 38.924213 39.179722 39.344167 39.410605 39.783369 40.047811 40.170278 40.269756 42.348889 41.385606 38.686817 39.005647 39.170572 39.294322 39.335144 39.673419 39.683900 40.016911 40.252750 40.289433 40.630133 41.139750 41.370800 41.711481 42.065599 42.411698 42.958644 42.994199 County Piatt Saline Monroe Wayne Lawrence Fayette Cumberland Greene Christian Macon Piatt Schuyler Champaign Jo Daviess DeKalb Martin Jackson Owen Ripley Clay Parke Shelby Boone Madison Randolph Benton Allen Porter Elkhart Cass Buren Van Ionia Ionia State Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Illinois Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Indiana Michigan Michigan Michigan Michigan Site name Sangamon River at Monticello, IL Little Saline River near Carrier Mills, IL IL Rockhouse Creek near Hecker, IL City, Wayne Fourmile Creek near IL near Petersburg, Tributary Raccoon Creek Raccoon Creek near Mulberry Grove, IL IL Woodbury, Island Creek near Coates Creek near Berdan, IL Creek near Morrisonville, IL Willow near Mt. Zion, IL Tributary Big Creek White Heath, IL near Tributary Camp Creek Cedar Creek near Camden, IL near Rantoul, IL Tributary Upper Salt Fork Aitken, IL Smallpox Creek at St. Joseph River near Newville, IN Beaver Creek near Huron, IN IN Cooley Creek near Seymour, Lick Creek near Freedom, IN Pipe Creek near Penntown, IN IN Big Slough near Riley, Rock Fork near Mansfield, IN Little Sugar Creek near New Palestine, IN Mounts Run near Zionsville, IN Little Duck Creek near Elwood, IN IN Mississinewa River near Union City, IN Owens Ditch near Fowler, IN Wayne, Ditch near Fort Wilbur Cobb Ditch near Kouts, IN Cobus Creek near Elkhart, IN Osborn Drain near Glenwood, MI Butternut Creek near South Haven, MI MI Little Libhart Creek near Lyons, Bellamy Creek near Ionia, MI Site number 05572000 03382125 05595210 03380600 03346565 05592760 03344435 05586597 05575030 05573200 05571950 05584790 03336790 05416050 04178000 384113086425401 390020086000801 391014086484501 391740085055701 392007087140201 394024087050901 394102085533101 400101086172501 401510085502501 401722084513201 403748087101301 410823084551101 412215087042801 414241086030101 04101531 04102726 04115851 04116023 - Selected sites in the United States sampled for perchlorate analysis.—Continued

IL-11 IL-02 IL-03 IL-04 IL-05 IL-06 IL-07 IL-08 IL-09 IL-10 IL-12 IL-13 IL-14 IL-15 IN-11 IN-01 IN-02 IN-03 IN-04 IN-05 IN-06 IN-07 IN-08 IN-09 IN-10 IN-12 IN-13 IN-14 IN-15 MI-01 MI-02 MI-03 MI-04 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, Tables 1, 3–6 23 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw Site type NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 58.47 feet Well Well 118.3 112.4 118.53 118.5 128.5 128.38 108.79 158.43 129.39 depth, in Unit Code Hydrologic 04050007 04050007 04080205 04100003 07010206 07020008 07020009 07020011 07020007 07020012 07010206 07030005 07040002 07040001 07040003 07040003 07040008 07110001 07110004 10090101 10220003 10220003 10200202 10250016 10270206 10270202 10270206 10270207 10270206 10270206 10270206 10270206 10270203 degrees Longitude, in decimal -84.872768 -85.241671 -83.246336 -84.498838 -93.310227 -94.998333 -94.289167 -93.908563 -93.909126 -93.737222 -92.852427 -92.890278 -93.468000 -92.477222 -91.944444 -91.788611 -91.990000 -91.869893 -91.388205 -106.836178 -96.540833 -96.283889 -96.157778 -98.548278 -97.745833 -97.143333 -97.916944 -97.331389 -97.678333 -98.857222 -98.896944 -98.479806 -97.891222 degrees Latitude, in decimal 42.651703 42.600869 43.504465 41.713106 45.049965 44.341944 43.890000 43.996633 44.357744 44.691389 44.746634 45.656111 44.254130 44.457778 44.200556 44.134167 43.699444 40.415872 39.684768 45.008863 41.560278 41.293333 41.015278 40.132556 40.224722 40.287500 40.314722 40.321667 40.350833 40.365000 40.452222 40.495500 40.555806 County Eaton Barry Tuscola Hillsdale Hennepin Redwood Blue Earth Blue Earth Le Sueur Carver Dakota Chisago Rice Goodhue Wabasha Winona Fillmore Clark Ralls Big Horn Dodge Douglas Sarpy Webster Thayer Jefferson Nuckolls Jefferson Fillmore Kearney Kearney Adams Clay State Michigan Michigan Michigan Michigan Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Minnesota Missouri Missouri Montana Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Site name Little Thornapple River near Gresham, MI Little MI Cedar Creek near Quimby, White Creek near Deford, MI South Branch MI Waldron, Laird Creek near in Minneapolis, MN Avenue Shingle Creek at Queen County Ditch 24 near Clements, MN Creek, MN Willow Judicial Ditch 85 near Little Cobb River near Beauford, MN Cherry Creek near Ottawa, MN Silver Creek near East Union, MN Mississippi river below L&D #2 at Hastings, MN MN Rush Creek above Mouth near City, Devil Creek near Morristown, MN Creek near Belvidere Mills, MN Wells MN Weaver, Creek near Trout Whitman, MN Creek near Valley Deering Duschee Creek above Lanesboro, MN MO River near Luray, Wyaconda Bear Creek at 29th Street Hannibal, MO MT River at State Line near Decker, Tongue Maple Creek near Nickerson, NE NE Waterloo, Elkhorn River at Platte River at Louisville, NE 2N 11W15CDDD1 3N 4W15DADA1 4N 2E25ADAA1 4N 5W18DAAA1 4N 1E 8DDDD1 5N 3W32DCDC1 5N 14W26DDDD1 6N 14W28DDCD1 7DDDC1 6N 10W 7N 5W21CDAD1 Site number 04116734 04117448 04150592 04177085 05288705 05316983 05318283 05320270 05325580 05329898 05331580 05339721 05351400 05355307 05377508 05377550 05384110 05495850 05502005 06306300 06800000 06800500 06805500 400757098325401 401329097444501 401715097083601 401853097550101 401918097195301 402103097404201 402154098512601 402708098534901 402943098284801 403314097532801 - Selected sites in the United States sampled for perchlorate analysis.—Continued

MI-05 MI-06 MI-07 MI-08 NE-11 NE-01 NE-02 NE-03 NE-04 NE-05 NE-06 NE-07 NE-08 NE-09 NE-10 NE-12 NE-13 MT-01 MN-11 MN-01 MN-02 MN-03 MN-04 MN-05 MN-06 MN-07 MN-08 MN-09 MN-10 MN-12 MN-13 MO-01 MO-02 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, 24 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 sw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type 43 NA 114 105 125 98.23 78.74 88.86 89 48.1 28.6 93.5 43.5 feet Well Well 77.37 123.5 53.63 106.5 92.39 37.61 58.83 93.27 38.57 33.25 50.77 114.07 102.2 100 125 105 120 113.57 118.21 100.71 depth, in Unit Code Hydrologic 10270206 10270204 10270204 10270204 10240006 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270203 10270202 10270202 10270203 10270203 10270203 10270202 10270203 10270203 10270201 10270201 10270201 10270201 10270201 10270201 degrees Longitude, in decimal -98.914167 -97.766944 -97.027500 -97.216944 -96.217028 -98.090000 -97.425833 -97.539444 -97.864167 -98.225556 -97.587551 -97.598056 -97.591667 -97.594444 -97.602778 -97.585833 -97.597500 -97.604667 -97.581944 -97.177383 -97.177383 -97.611944 -97.639444 -97.695556 -97.177500 -97.650556 -97.625556 -97.177133 -97.177133 -97.162361 -97.162361 -97.162361 -97.957222 degrees Latitude, in decimal 40.558333 40.583889 40.588889 40.633056 40.669500 40.672222 40.688056 40.745833 40.756944 40.846389 40.858900 40.859444 40.862778 40.863056 40.863611 40.864167 40.866667 40.868000 40.868611 40.890658 40.890658 40.871111 40.873333 40.873333 40.884444 40.886944 40.887222 40.904561 40.904561 40.894572 40.894572 40.894572 40.898056 County Kearney Fillmore Saline Saline Otoe Clay Fillmore York Hamilton Hamilton York York York York York York York York York Seward Seward York York York Seward York York Seward Seward Seward Seward Seward Hamilton State Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Site name 7N 14W20DADA1 7N 4W10CCCB1 7N 3E12ADDD1 8N 2E29ADDD1 Creek near Syracuse, NE Wolf 8N 7W10DDAA1 4DADD1 8N 1W 9N 2W15CBCC1 9N 5W10DDDD1 10N 8W10CCBB1 6DCCC1 OFPS-38 10N 2W 1DDAD1 FP2-43 10N 3W 6CABB1 FP3-33 10N 2W 6CBDB1 UWT1-53 10N 2W 1DACC1 UWT2-23 10N 3W 6DBBD1 OFPN-88 10N 2W 6BCCB1 UWT3-34 10N 2W 1BDA1 FP4-28 10N 3W 6ADBB1 UWT4-85 10N 2W 2E26CCBB2 FP3-105 11N 2E26CCBB3 FP3-125 11N 1BBA1 NWT1-39 10N 3W 2CBBD1 FP5-45 10N 3W 3W31DDCD1 11N 2E34AADA1 11N AWT3-73 3W34BBA1 11N AWT1-83 3W26DCC1 11N 2E23CCBB2 FP2-105 11N 2E23CCBB3 FP2-125 11N 2E26ADCC1 FP1-90 11N 2E26ADCC2 FP1-105 11N 2E26ADCC3 FP1-123 11N 6W25BACC1 11N Site number 403330098545101 403502097460101 403520097013901 403759097130101 404010096130101 404020098052401 404117097253301 404445097322201 404525097515101 405047098133201 405131097351401 405134097355301 405146097353001 405147097354001 405149097361001 405151097350901 405200097355101 405205097361701 405207097345501 405212097110002 405212097110003 405216097364301 405224097382201 405224097414401 405304097103901 405313097390201 405314097373201 405330097110002 405330097110003 405340097094501 405340097094502 405340097094503 405353097572601 - Selected sites in the United States sampled for perchlorate analysis.—Continued

NE-14 NE-15 NE-16 NE-17 NE-18 NE-19 NE-20 NE-21 NE-22 NE-23 NE-24 NE-25 NE-26 NE-27 NE-28 NE-29 NE-30 NE-31 NE-32 NE-33 NE-34 NE-35 NE-36 NE-37 NE-38 NE-39 NE-40 NE-41 NE-42 NE-43 NE-44 NE-45 NE-46 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, Tables 1, 3–6 25 sw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type 22 79 91 94 60 83 28 NA 105 129 38 25 65 50 98.5 24.5 81.1 71.1 18.2 feet Well Well 114.1 76.77 122.5 93.57 133.5 103.5 104.5 110 232 193.06 140 670 100 116.47 depth, in Unit Code Hydrologic 10270203 10270201 10270201 10270201 10190018 10270201 10270201 10270201 10270201 10270201 10200203 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10220003 10180014 10200201 10220003 10220003 10210002 10210001 10210001 10210001 10210008 degrees Longitude, in decimal -97.682222 -97.196117 -97.196117 -97.893333 -102.044861 -97.368667 -97.579167 -97.368056 -97.761667 -97.503056 -96.624778 -96.548083 -96.548083 -96.548083 -96.674250 -96.548528 -96.548528 -96.548528 -96.546778 -96.546778 -96.546778 -96.546550 -96.546431 -96.546528 -101.695944 -97.716111 -96.999683 -97.161464 -100.152694 -102.425444 -101.450583 -101.610889 -99.586278 degrees Latitude, in decimal 40.901667 40.908911 40.908911 41.046389 41.047556 41.067167 41.088889 41.097778 41.119444 41.215556 41.276639 41.559583 41.559583 41.559583 41.561083 41.561389 41.561389 41.561389 41.563250 41.563250 41.563250 41.563953 41.563956 41.563944 41.569944 41.647222 41.728656 41.757581 41.796889 42.057167 42.082778 42.087611 42.139056 County York Seward Seward Hamilton Keith Butler Polk Butler Polk Polk Saunders Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Dodge Arthur Platte Colfax Stanton Blaine Sheridan Grant Grant Rock State Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska Site name 11N 3W20DCC1 AWT2-71 3W20DCC1 11N 2E22CBBB2 FP4-105 11N 2E22CBBB3 FP4-129 11N 4BAAA1 12N 5W SB01204232CDD 13N 1W25DAAD1 13N 2W20BBBC1 13N 1E18BCCC1 13N 4W10BAAA1 2ADDA1 14N 2W Duck Creek near Colon, NE ACTFS1-1A WELL 5DBAB1 NAWQA 18N 8W ACTFS1-1B WELL 5DBAB2 NAWQA 18N 8W ACTFS1-1C WELL 5DBAB3 NAWQA 18N 8W 18N 7E 6BCCC1 CNBRLUSCR1 DO-24 ACTFS1-2A WELL 5ACDC1 NAWQA 18N 8W ACTFS1-2B WELL 5ACDC2 NAWQA 18N 8W ACTFS1-2C WELL 5ACDC3 NAWQA 18N 8W ACTFS1-3A WELL 5ACAC1 NAWQA 18N 8W ACTFS1-3B WELL 5ACAC2 NAWQA 18N 8W ACTFS1-3C WELL 5ACAC3 NAWQA 18N 8W ACTFS1-4A WELL 5ABDD1 NAWQA 18N 8W ACTFS1-4B WELL 5ABDD2 NAWQA 18N 8W ACTFS1-4C WELL 5ABDD3 NAWQA 18N 8W 19N 38W33DDDA1 6CBCB1 19N 3W 20N 4E 5CCDC1 CNBRLUSCR1 CO-13 21N 2E35ABAA1 CNBRLUSCR1 S-11 21N 25W13ABAA1 24N 44W16DBDB1 2DABC1 24N 36W 4ACBB1 24N 37W 25N 20W13ADAC1 Site number 405406097405601 405420097114002 405420097114003 410247097533601 410251102024201 410410097220601 410520097344501 410552097220501 410710097454201 411256097301101 411636096372901 413334096325301 413334096325302 413334096325303 413340096402701 413341096325501 413341096325502 413341096325503 413348096324801 413348096324802 413348096324803 413350096324701 413350096324702 413350096324703 413412101414501 413850097425801 414343096595801 414527097094101 414748100090901 420326102253201 420458101270201 420515101363901 420821099351101 - Selected sites in the United States sampled for perchlorate analysis.—Continued

NE-47 NE-48 NE-49 NE-50 NE-51 NE-52 NE-53 NE-54 NE-55 NE-56 NE-57 NE-58 NE-59 NE-60 NE-61 NE-62 NE-63 NE-64 NE-65 NE-66 NE-67 NE-68 NE-69 NE-70 NE-71 NE-72 NE-73 NE-74 NE-75 NE-76 NE-77 NE-78 NE-79 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, 26 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw Site type NA NA NA NA NA NA NA NA NA 90 80 80 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 113 175 180 feet Well Well depth, in Unit Code Hydrologic 10210001 10150003 10210006 10150004 10150004 10150004 13020101 13020101 13020201 13020203 14080101 14080104 14080105 14080105 15010015 16050201 16050102 16050102 05080001 04100007 05060002 05060002 05060002 05080003 05040006 05060001 05040006 05040003 04100007 05040002 04100009 04100010 degrees Longitude, in decimal -101.900500 -102.298056 -101.473889 -101.686472 -100.426583 -100.572944 -105.754459 -106.141667 -106.439444 -106.678889 -107.697500 -108.201944 -108.225833 -108.683056 -115.047776 -119.689341 -119.866472 -119.486186 -83.831596 -84.266059 -83.335972 -83.055972 -82.851250 -84.781806 -82.051806 -83.266111 -82.593056 -82.290278 -84.114861 -82.280000 -84.098333 -83.582361 degrees Latitude, in decimal 42.221361 42.355639 42.360500 42.475028 42.734278 42.864972 36.320023 35.874444 35.444444 34.920556 36.801389 36.722500 36.723056 36.776667 36.139695 38.878240 39.510500 39.565453 39.964227 40.948662 38.777917 38.957639 39.338611 39.365833 39.950278 40.034167 40.074444 40.437222 40.616528 40.880972 41.332222 41.368472 County Cherry Sheridan Cherry Cherry Cherry Cherry Taos Santa Fe Sandoval Valencia San Juan San Juan San Juan San Juan Clark Douglas Washoe Storey Clark Putnam Adams Scioto Ross Butler Muskingum Madison Licking Knox Auglaize Adams Henry Wood State Nebraska Nebraska Nebraska Nebraska Nebraska Nebraska New Mexico New Mexico New Mexico New Mexico New Mexico New Mexico New Mexico New Mexico Nevada Nevada Nevada Nevada Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Site name Las Vegas, NV Vegas, Las Reno, NV 26N 39W19ADCB1 2AADB1 27N 43W 28N 36W36CBBB1 29N 37W20DCDA1 32N 27W24ACBB1 1BB 1 33N 28W NM Taos, Junction Bridge near Taos Rio Grande below Rio Grande at Otowi Bridge, NM Rio Grande at San Felipe, NM Rio Grande at Isleta, NM Archuleta, NM San Juan River near Animas River at Farmington, NM San Juan River at Farmington, NM San Juan River at Shiprock, NM Confluence near Wash below Flamingo Wash Vegas Las East Fork Carson River near Dresslerville, NV Plant Intake near Treatment River at Chalk Bluff Truckee River at Clark, NV Truckee OH Mad River at St. Paris Pike Eagle City, Auglaize River near Fort Jennings, OH Mill Creek at Blue Creek, OH Camp Creek near Coopersville, OH Creek near Mooresville, OH Walnut Little Whitewater River near Okeana, OH Dry Fork Run near Zanesville, OH Timber OH Ditch near Plain City, Yutzy Moots Run near Granville, OH East Branch Jelloway Creek near Danville, OH OH Wapakoneta, Blackhoof Creek near Ashland, OH Jerome Fork near School Creek near Napoleon, OH North Branch of Portage River near Bowling Green, OH Site number 421317101540201 422120102175301 422138101282601 422830101411101 424403100253501 425154100342301 08276500 08313000 08319000 08331000 09355500 09364500 09365000 09368000 094196783 10309010 10347699 10350500 03267900 04186500 384641083201001 385728083032101 392019082510401 392157084465401 395701082030601 400203083155801 400428082353501 402614082172501 403700084065301 405251082164801 411956084055401 412207083345601 - Selected sites in the United States sampled for perchlorate analysis.—Continued

NE-80 NE-81 NE-82 NE-83 NE-84 NE-85 NV-01 NV-02 NV-03 NV-04 OH-11 OH-01 OH-02 OH-03 OH-04 OH-05 OH-06 OH-07 OH-08 OH-09 OH-10 OH-12 OH-13 OH-14 NM-01 NM-02 NM-03 NM-04 NM-05 NM-06 NM-07 NM-08 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, Tables 1, 3–6 27 sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw Site type NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA feet Well Well depth, in 10170203 10170102 07020001 12100301 12100301 13030102 04030104 04030103 04030202 04030202 04040003 07030005 07050006 07050005 07050007 07040007 07040006 07070004 07070005 07070005 07060003 07060003 07060005 07090004 10080012 10090101 10090101 10090101 Unit Code Hydrologic degrees -96.583611 -97.163333 -96.651667 -98.412793 -98.355846 -88.597606 -88.218992 -89.086781 -88.555658 -88.088399 -92.529917 -90.921538 -91.799336 -92.044097 -90.840692 -90.761244 -90.357351 -90.355128 -90.716516 -90.714293 -90.479295 -90.359017 -89.585399 Longitude, in decimal -106.540822 -109.973519 -107.020905 -106.988959 -106.839789 degrees 43.266389 43.496389 45.167500 29.357180 29.222185 31.802885 45.146086 44.465822 45.373853 44.729375 43.517942 44.920245 44.623017 44.734129 45.287850 44.081353 43.827024 43.651446 43.461368 43.122484 42.889156 42.781659 42.630833 42.746394 44.513278 44.900249 44.886361 44.983863 Latitude, in decimal County Lincoln Turner Grnat Bexar Bexar El Paso Oconto Outagamie Langlade Shawano Washington St. Croix Clark Dunn Barron Monroe Monroe Vernon Richland Grant Grant Grant Lafayette Greene Park Sheridan Sheridan Sheridan State South Dakota South Dakota South Dakota Texas Texas Texas Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wisconsin Wyoming Wyoming Wyoming Wyoming Site name Monroe, SD Milbank, SD WI Little Beaver Creek near Canton, SD River near Vermillion to East Fork Tributary Unnamed River near Yellowbank to North Fork Tributary Unnamed TX Antonio, Salado Creek at Loop 13 San TX Antonio River near Elmendorf, San TX Rio Grande at El Paso, WI South Branch Oconto River near Markton, WI Duck Creek at Seminary Road near Oneida, near Summit Lake, T Hunting River on County Highway WI River near Shawano, Wolf to Tributary WI Stoney Creek at Boltonville, WI Parker Creek near River Falls, WI Black Creek near Fairchild, WI Cranberry Creek at Meridean, WI Arland, Silver Creek near WI Soper Creek at Cataract, WI Little La Crosse River near Melvina, WI Branch Baraboo River at Hillsboro, West WI Hawkins Creek at Rockbridge, WI Crooked Creek at Boscobel, WI Rogers Branch near Lancaster, WI Arthur, Little Platte River near WI Galena River at Jenkinsville, WI Branch at Monticello, West Little Sugar River WY Crow Creek at Mouth Pahaska, WY River at Monarch, Tongue WY Acme, Goose Creek near WY Acme, Prairie Dog Creek near Site number 431559096350100 432947097094800 451003096390600 08178800 08181800 08364000 04070621 04072050 04074730 04078005 040863315 05341865 05365962 05367064 05367803 05381441 05382415 054041139 054067125 05407217 05412880 05414133 05414924 05436361 06279795 06299980 06305700 06306250 - Selected sites in the United States sampled for perchlorate analysis.—Continued

WI-11 WI-01 WI-02 WI-03 WI-04 WI-05 WI-06 WI-07 WI-08 WI-09 WI-10 WI-12 WI-13 WI-14 WI-15 WI-16 WI-17 WI-18 SD-01 SD-02 SD-03 TX-01 TX-02 TX-03 WY-01 WY-02 WY-03 WY-04 (figs. 2–9) Map identifi cation number Table 1. Table groundwater] surface water; gw, [NA, not applicable; sw, 28 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 - .44 .82 .81 .41 .96 0.87 6.23 2.7 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 tration (μg/L ) Perchlorate concen

1150 1100 1550 1551 1038 1340 1340 0920 0921 1040 1040 1410 1410 1400 1401 0845 0855 1210 1215 1245 1045 1330 1400 1406 1300 1302 1400 1401 1030 1040 0840 0841 0710 0720 (24 hour) Sample time year) 08/12/2004 08/12/2004 07/12/2004 07/12/2004 07/14/2004 07/14/2004 07/13/2004 07/13/2004 07/15/2004 07/15/2004 07/19/2004 07/19/2004 10/20/2004 10/20/2004 09/24/2004 09/24/2004 09/20/2004 09/20/2004 10/21/2004 10/21/2004 09/14/2004 09/14/2004 08/14/2004 08/14/2004 09/02/2004 09/02/2004 08/16/2004 08/16/2004 08/17/2004 08/17/2004 10/07/2004 10/07/2004 09/08/2004 09/08/2004 (momth/day/ Sample date type Sample ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate ambient replicate Site name Santa Ana River below Prado Dam, CA Santa Ana River below Prado Dam, CA Santa 017S002W27P002S 017S002W27P002S 011S004W04K005S 011S004W04K005S 010S003E27D002S 010S003E27D002S 010S005W26C003S 010S005W26C003S 010S001E05B001S 010S001E05B001S Creek near Morrisonville, IL Willow Creek near Morrisonville, IL Willow Little Sugar Creek near New Palestine, IN Little Sugar Creek near New Palestine, IN IN Mississinewa River near Union City, IN Mississinewa River near Union City, Cobus Creek near Elkhart, IN Cobus Creek near Elkhart, IN Bellamy Creek near Ionia, MI Bellamy Creek near Ionia, MI Whitman, MN Creek near Valley Deering Whitman, MN Creek near Valley Deering Duschee Creek above Lanesboro, MN Duschee Creek above Lanesboro, MN MO River near Luray, Wyaconda MO River near Luray, Wyaconda Vegas, NV Confluence near Las Wash below Flamingo Wash Vegas Las Vegas, NV Confluence near Las Wash below Flamingo Wash Vegas Las North Branch of Portage River near Bowling Green, OH North Branch of Portage River near Bowling Green, OH WI Arthur, Little Platte River near WI Arthur, Little Platte River near Site number 11074000 11074000 323925117044001 323925117044001 331443117181201 331443117181201 331659116394701 331659116394701 331707117223601 331707117223601 332024116535701 332024116535701 05575030 05575030 394102085533101 394102085533101 401722084513201 401722084513201 414241086030101 414241086030101 04116023 04116023 05377550 05377550 05384110 05384110 05495850 05495850 094196783 094196783 412207083345601 412207083345601 05414133 05414133 Quality-assurrance-quality-control samples (replicates) for perchlorate reconnaissance study in selected areas of the United St ates.

CA-03 CA-03 CA-04 CA-04 CA-08 CA-08 CA-09 CA-09 CA-10 CA-10 CA-11 CA-11 IL-10 IL-10 IN-08 IN-08 IN-11 IN-11 IN-15 IN-15 MI-04 MI-04 MN-12 MN-12 MN-13 MN-13 MO-01 MO-01 NV-01 NV-01 OH-14 OH-14 WI-16 WI-16 number (figs. 2–9) Map identification Table 3. Table [<, less than] Tables 1, 3–6 29 - .92 .6 .71 .87 .45 .44 .82 0.68 1.93 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 tion (μg/L) concentra Perchlorate 1115 1115 1105 1150 1100 1500 1200 0800 0830 1420 1325 1055 1030 0755 1320 1000 1030 1320 0930 1550 1551 1038 1030 1340 1340 0920 0921 1040 hour) Sample time (24 years) (month/day/ Sample date 07/07/2004 07/07/2004 07/08/2004 09/01/2004 09/07/2004 08/11/2004 08/12/2004 08/19/2004 08/10/2004 08/31/2004 09/02/2004 09/09/2004 08/27/2004 08/13/2004 08/18/2004 08/13/2004 08/13/2004 08/12/2004 08/12/2004 07/12/2004 07/12/2004 07/12/2004 07/15/2004 07/20/2004 07/14/2004 07/14/2004 07/13/2004 07/13/2004 07/15/2004 USGS Project SWTREND SWTREND SWTREND AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ AZDEQ SWTREND SWTREND SWTREND SWTREND GAMA GAMA GAMA GAMA GAMA GAMA GAMA GAMA GAMA GAMA - gram USGS Pro NAWQA NAWQA NAWQA COOP NAWQA COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP NAWQA NAWQA NAWQA NAWQA COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate replicate replicate replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw gw Site type Site name AZ AZ Dam, Yocum Creek near Oak Grove, AR Creek near Oak Grove, Yocum AR River near Boxley, Buffalo AR North Sylamore Creek near Fifty Six, 13N04E12ABB1 AZ Colorado River at Lees Ferry, near Solomon, Valley Gila River at Head of Safford AZ Gila River at Calva, AZ San Pedro River at Charleston, AZ Gila River at Kelvin, AZ Salt River near Roosevelt, AZ Salt River below Stewart Mountain Dam, AZ River near Clarkdale, Verde AZ River near Childs, Verde East Creek above Horseshoe Tangle River below Verde AZ River below Bartlett Dam, Verde Ana River above Seven Oaks Dam, CA Santa Creek near San Bernardino, CA Warm Ana River below Prado Dam, CA Santa Ana River below Prado Dam, CA Santa 017S002W27P002S 017S002W27P002S 016S001W03E001S 015S001E18L005S 013S002W05D001S 011S004W04K005S 011S004W04K005S 010S003E27D002S 010S003E27D002S 010S005W26C003S Site number 07053250 07055646 07060710 354635090365601 09380000 09448500 09466500 09471000 09474000 09498500 09502000 09504000 09507980 09508500 09510000 11049400 11060400 11074000 11074000 323925117044001 323925117044001 324840116584401 325157116551401 330447117065301 331443117181201 331443117181201 331659116394701 331659116394701 331707117223601 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.

AZ-11 AZ-01 AZ-02 AZ-03 AZ-04 AZ-05 AZ-06 AZ-07 AZ-08 AZ-09 AZ-10 AR-01 AR-02 AR-03 AR-04 CA-01 CA-02 CA-03 CA-03 CA-04 CA-04 CA-05 CA-06 CA-07 CA-08 CA-08 CA-09 CA-09 CA-10 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport TANC, Monitoring Network; <, less than] River Surface-Water-Quality 30 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 - .81 .63 1.1 3.32 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < 0.4 tion (μg/L) concentra Perchlorate 1110 1135 1100 1135 1100 1040 1410 1410 1000 0930 1230 1345 1745 1445 1200 1045 0805 1640 0930 0900 1415 0840 0840 0840 0940 1645 1400 hour) Sample time (24 year) 11/04/2004 07/15/2004 07/19/2004 07/19/2004 06/10/2004 06/08/2004 06/08/2004 07/20/2004 07/21/2004 07/22/2004 07/22/2004 06/02/2004 07/29/2004 09/07/2004 05/26/2004 06/25/2004 07/28/2004 08/26/2004 06/30/2004 08/18/2004 08/19/2004 08/18/2004 08/18/2004 08/18/2004 08/17/2004 05/17/2004 05/18/2004 07/20/2004 07/20/2004 (month/day/ Sample date SPLT SPLT RIOG RIOG RIOG RIOG RIOG RIOG USGS UCOL UCOL GAMA GAMA GAMA Project SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND - gram COOP COOP COOP COOP COOP COOP COOP NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA USGS Pro ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type Site name CO 010S005W26C003S 010S001E05B001S 010S001E05B001S CO Cherry Creek at Denver, CO Lonetree Creek near Greeley, CO South Platte River near Kersey, Fountain Creek below 8th Street at Colorado Springs, Fountain Creek near Fountain, CO Fountain Creek near Pinon, CO Fountain Creek at Pueblo, CO Dry Fork at Upper Station near De Beque, CO Dry Fork at Upper Station near De Beque, CO Dry Fork at Upper Station near De Beque, CO Colorado River near Colorado-Utah State Line Colorado River near Colorado-Utah State Line Colorado River near Colorado-Utah State Line Colorado River near Colorado-Utah State Line Colorado River near Colorado-Utah State Line San Juan River at Four Corners, CO NA03400929CBB NA03800812ACA NA03900709ABB NA03900709ABB NA03900709ABB NA04200931BAD NB04900101BCB SC01408602BCC SC00806608BCD SC00606626BDD Site number 331707117223601 332024116535701 332024116535701 06713500 06753990 06754000 07103707 07106000 07106300 07106500 09095300 09095300 09095300 09163500 09163500 09163500 09163500 09163500 09371010 370936106010501 373323106025001 373849106124501 373849106124501 373849106124501 375054106013401 383232106554700 385213106584700 392210104482901 393003104450001 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

CA-11 CA-11 CO-11 CA-10 CO-01 CO-02 CO-03 CO-04 CO-05 CO-06 CO-07 CO-08 CO-08 CO-08 CO-09 CO-09 CO-09 CO-09 CO-09 CO-10 CO-12 CO-13 CO-13 CO-13 CO-14 CO-15 CO-16 CO-17 CO-18 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality Tables 1, 3–6 31 - .64 .62 .4 4.19 1.83 1.12 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < 0.4 tion (μg/L) concentra Perchlorate 1115 1130 1100 1050 1215 1020 1240 1330 1350 0920 0920 1520 1320 1340 1400 0838 1025 0915 1255 1520 1500 1045 1005 hour) Sample time (24 year) 11/16/2004 11/16/2004 07/21/2004 09/08/2004 07/19/2004 09/07/2004 05/19/2004 07/19/2004 05/20/2004 07/14/2004 07/15/2004 07/07/2004 07/14/2004 07/13/2004 10/26/2004 10/26/2004 08/03/2004 10/21/2004 10/20/2004 08/02/2004 10/20/2004 08/02/2004 10/25/2004 (month/day/ Sample date SPLT SPLT SPLT SPLT SPLT SPLT SPLT USGS UCOL UCOL UCOL UCOL Project SWTREND SWTREND SWTREND SWTREND - gram NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS/ EPALIPS/ EPALIPS/ USGS Pro blank ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw gw Site type Site name CO Springs, IA Springs, IA IA Garner, IA SC00506732DCA SC00507834BCB SC00506610DBD SC00507812ACB SC00508009AAC SC00506604BDD SC00107602DAC SB00305703BBA SB00506532DDB Thompson below Moraine Park near Estes Park, Big SB00505930CBA SB01004805CCC to Beaver Creek near Lime Tributary Unknown to Beaver Creek near Lime Tributary Unknown IA Silver Creek near Hanover, Bohemian Creek near Protivin, IA North Fork Maquoketa River at NE Dyersville, IA IA Tripoli, River near Wapsipinicon Unnamed Creek near Fairbank, IA to East Branch Iowa River at Tributary Unknown Iowa River near Rowan, IA Ditch No. 5 near Galt, IA South Fork Iowa River Northeast of New Providence, South Minerva Creek at Clemons, IA Site number 393408104544001 393431106070801 393742104453801 393758106041401 393830106210600 393846104465601 395929105510300 401544103443101 402104104404501 402114105350101 402213104015501 405159102444201 05387313 05387313 05388325 05411595 05418080 05420680 05420858 05448910 05449500 05449580 05451210 05451425 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

IA-11 IA-01 IA-01 IA-02 IA-03 IA-04 IA-05 IA-06 IA-07 IA-08 IA-09 IA-10 CO-19 CO-20 CO-21 CO-22 CO-23 CO-24 CO-25 CO-26 CO-27 CO-28 CO-29 CO-30 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality 32 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 - .73 .41 .64 .47 .44 1.15 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < 0.4 tion (μg/L) concentra Perchlorate 1115 1100 1130 1130 1130 1012 0930 1315 1215 1000 1015 1210 1405 1005 0800 1600 0815 1010 0820 1500 1230 1000 0130 1530 1600 1200 1340 hour) Sample time (24 year) 10/20/2004 10/21/2004 10/01/2004 08/05/2004 10/04/2004 09/30/2004 09/30/2004 10/26/2004 10/25/2004 10/25/2004 10/05/2004 10/05/2004 10/04/2004 10/06/2004 10/06/2004 10/26/2004 10/05/2004 10/05/2004 10/29/2004 07/06/2004 07/06/2004 07/14/2004 07/14/2004 07/01/2004 07/08/2004 07/17/2004 06/28/2004 06/29/2004 (month/day/ Sample date USGS Project IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM SWTREND - gram COOP COOP COOP COOP COOP COOP COOP COOP COOP NAWQA EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS USGS Pro ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw Site type Site name Lake near Park, IA Manilla, IA Little Lime Creek near Nora Springs, IA Black Hawk Creek near Holland, IA IA Little Mosquito Creek near Moscow, IA Wapello, Iowa River at Buck Creek near New Sharon, IA Creek near Rome, IA Wolf IA to Suger Creek at La Crew, Tributary Branch West Whittemore, IA Prairie Creek near Brushy Creek near Duncombe, IA IA Yetter, Fork Camp Creek near West IA Springbrook Creek at Bagley, North Branch River at McBride, IA Brush Creek near Lucas, IA Rat Creek near Matlock, IA Fork Little Sioux River below Silver West Tributary Lost Island Outlet above Dickens, IA Anthon, IA Big Creek near Nishnabotna River near West Fork West to Tributary Fisher Creek near Shenandoah, IA 068N40W07BCAA 069N40W26BABD 069N36W19CD 070N39W27 072N41W27CDCC 072N41W24DAD 072N38W29BA 074N40W22ADDB 075N44W22DADA Site number 05459800 05463080 05464925 05465500 05472330 05473340 05474195 05476680 05480610 05482361 05483463 05485800 05487770 06483471 06603760 06605395 06606650 06807278 06809775 404327095284801 404521095235801 404531095020502 404957095183501 410007095330501 410107095300001 410118095144001 411154095252501 411649095525001 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

IA-12 IA-13 IA-14 IA-15 IA-16 IA-17 IA-18 IA-19 IA-20 IA-21 IA-22 IA-23 IA-24 IA-25 IA-26 IA-27 IA-28 IA-29 IA-30 IA-31 IA-32 IA-33 IA-34 IA-35 IA-36 IA-37 IA-38 IA-39 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality Tables 1, 3–6 33 .95 .56 .72 .74 1.73 1.27 1.33 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) Perchlorate concentration 820 1115 1130 1130 1100 1130 1140 1145 1130 1500 1245 1530 1330 1230 1230 0930 1330 1400 1000 1030 1330 1450 1030 0930 1445 0730 1600 1440 0915 hour) Sample time (24 year) (month/day/ Sample date 07/01/2004 08/05/2004 09/12/2004 07/13/2004 07/13/2004 08/05/2004 09/08/2004 07/27/2004 06/29/2004 06/30/2004 06/30/2004 06/30/2004 06/30/2004 07/20/2004 07/15/2004 07/13/2004 06/29/2004 06/29/2004 07/14/2004 07/22/2004 09/12/2004 07/12/2004 08/30/2004 08/03/2004 08/02/2004 08/03/2004 08/31/2004 07/13/2004 08/31/2004 USGS Project IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM IAGWM

USGS COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP COOP Program ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient Sample type gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type Site name 076N16W25CBDA 077N41W15ACDD 077N23W03AAAA 078N32W27ADDC 078N25W15CAAC 079N36W29BBCA 079N27W28BAAA 079N20W13ADDD 079N42W08DCCB 04510 079N21W11ABBB 079N21W01CCCA 080N18W26AADC 080N35W24CBCC 081N39W13CACB 03147 081N29W10BBBA 21882 082N34W17DDBA 082N13W13DACB 083N07W17DACD 083N27W01ABCC 084N27W13DCAA 084N18W07BCAD 089N03E18AADB 07468 091N20W05DBCC 40114 092N46W03CCAB 093N48W31CCDD 094N48W03ABDA 096N37W03DDCC 098N08W16CABD 099N40W14DCCC Site number 412117092392301 412812095322701 413031093285501 413132094304202 413342093432801 413743095041201 413744093595501 413907093070201 413943095453601 414024093153901 414029093145601 414251092541701 414315094524201 414933095201802 415055094131201 415435094492801 415442092180201 415949091404901 420156093562402 420453093561401 420607092594501 423138090383601 424312093135201 424838096161001 424921096334701 425940096294501 430923095114501 431816091474401 432314095320001 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

IA-40 IA-41 IA-42 IA-43 IA-44 IA-45 IA-46 IA-47 IA-48 IA-49 IA-50 IA-51 IA-52 IA-53 IA-54 IA-55 IA-56 IA-57 IA-58 IA-59 IA-60 IA-61 IA-62 IA-63 IA-64 IA-65 IA-66 IA-67 IA-68 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water Ground Regional Plains High HPGW, Network; Monitoring Groundwater IAGWM, Iowa Basin; River Platte South SPLT, Basin; River Colorado UCOL, Upper Valley; Grande RIOG, Rio River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality 34 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 .41 1.49 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) < 0.4 Perchlorate concentration 1140 1005 1245 1330 0915 0900 1220 1410 0915 1040 0950 1400 1401 1030 1300 1540 0920 0935 0900 1600 1035 0915 1045 1330 0925 0845 hour) Sample time (24 year) 11/09/2004 11/23/2004 11/08/2004 11/08/2004 11/09/2004 11/09/2004 08/06/2004 12/15/2004 08/05/2004 10/05/2004 10/26/2004 10/25/2004 10/16/2004 10/04/2004 09/28/2004 10/20/2004 10/20/2004 10/20/2004 09/29/2004 10/05/2004 10/19/2004 09/30/2004 09/08/2004 10/26/2004 09/23/2004 09/24/2004 (month/day/ Sample date USGS Project SWTREND SWTREND SWTREND SWTREND SWTREND

NAWQA NAWQA NAWQA NAWQA NAWQA USGS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS Program EPALIPS/ EPALIPS/ EPALIPS/ EPALIPS/ EPALIPS/ ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw Site type Site name Sugar Creek at Milford, IL Sugar Creek at Milford, IL Sangamon River at Monticello, IL Sangamon River at Monticello, IL Little Saline River near Carrier Mills, IL IL Rockhouse Creek near Hecker, IL City, Wayne Fourmile Creek near IL near Petersburg, Tributary Raccoon Creek Raccoon Creek near Mulberry Grove, IL IL Woodbury, Island Creek near Coates Creek near Berdan, IL Creek near Morrisonville, IL Willow Creek near Morrisonville, IL Willow near Mt. Zion, IL Tributary Big Creek White Heath, IL near Tributary Camp Creek Cedar Creek near Camden, IL near Rantoul, IL Tributary Upper Salt Fork Aitken, IL Smallpox Creek at St. Joseph River near Newville, IN Beaver Creek near Huron, IN IN Cooley Creek near Seymour, Lick Creek near Freedom, IN Pipe Creek near Penntown, IN IN Big Slough near Riley, Rock Fork near Mansfield, IN Little Sugar Creek near New Palestine, IN Site number 05525500 05525500 05572000 05572000 03382125 05595210 03380600 03346565 05592760 03344435 05586597 05575030 05575030 05573200 05571950 05584790 03336790 05416050 04178000 384113086425401 390020086000801 391014086484501 391740085055701 392007087140201 394024087050901 394102085533101 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

IL-11 IL-01 IL-01 IL-02 IL-02 IL-03 IL-04 IL-05 IL-06 IL-07 IL-08 IL-09 IL-10 IL-10 IL-12 IL-13 IL-14 IL-15 IN-01 IN-02 IN-03 IN-04 IN-05 IN-06 IN-07 IN-08 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport TANC, Monitoring Network; <, less than] River Surface-Water-Quality Tables 1, 3–6 35 .85 .87 .8 1.58 2.53 1.8 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) < 0.4 Perchlorate concentration 900 1100 1135 1145 0855 0930 0945 1210 0910 0930 1610 1215 1245 1230 1600 1340 1045 1330 1230 1400 1025 1420 1210 1310 1005 1040 1300 1016 hour) Sample time (24 year) 11/10/2004 09/24/2004 09/30/2004 09/20/2004 09/20/2004 09/22/2004 09/21/2004 09/21/2004 10/21/2004 10/21/2004 10/13/2004 09/08/2004 09/13/2004 09/14/2004 09/14/2004 10/12/2004 09/23/2004 09/29/2004 09/15/2004 08/25/2004 10/06/2004 10/07/2004 10/07/2004 08/23/2004 10/07/2004 09/03/2004 07/28/2004 08/13/2004 (month/day/ Sample date USGS Project SWTREND SWTREND SWTREND

NAWQA NAWQA USGS NAWQA NAWQA EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS Program EPALIPS/ EPALIPS/ blank ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate replicate replicate replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw Site type Site name MN Little Sugar Creek near New Palestine, IN Mounts Run near Zionsville, IN Little Duck Creek near Elwood, IN IN Mississinewa River near Union City, IN Mississinewa River near Union City, IN Owens Ditch near Fowler, IN Wayne, Ditch near Fort Wilbur Cobb Ditch near Kouts, IN Cobus Creek near Elkhart, IN Cobus Creek near Elkhart, IN Osborn Drain near Glenwood, MI Butternut Creek near South Haven, MI MI Little Libhart Creek near Lyons, Bellamy Creek near Ionia, MI Bellamy Creek near Ionia, MI Thornapple River near Gresham, MI Little MI Cedar Creek near Quimby, White Creek near Deford, MI South Branch MI Waldron, Laird Creek near in Minneapolis, Avenue Shingle Creek at Queen County Ditch 24 near Clements, MN County Ditch 24 near Clements, MN Creek, MN Willow Judicial Ditch 85 near Little Cobb River near Beauford, MN Little Cobb River near Beauford, MN Cherry Creek near Ottawa, MN Silver Creek near East Union, MN Mississippi river below L&D #2 at Hastings, MN Site number 394102085533101 400101086172501 401510085502501 401722084513201 401722084513201 403748087101301 410823084551101 412215087042801 414241086030101 414241086030101 04101531 04102726 04115851 04116023 04116023 04116734 04117448 04150592 04177085 05288705 05316983 05316983 05318283 05320270 05320270 05325580 05329898 05331580 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

IN-11 IN-11 IN-08 IN-09 IN-10 IN-12 IN-13 IN-14 IN-15 IN-15 MI-01 MI-02 MI-03 MI-04 MI-04 MI-05 MI-06 MI-07 MI-08 MN-01 MN-02 MN-02 MN-03 MN-04 MN-04 MN-05 MN-06 MN-07 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water Ground Regional Plains High HPGW, Network; Monitoring Groundwater IAGWM, Iowa Basin; River Platte South SPLT, Basin; River Colorado UCOL, Upper Valley; Grande RIOG, Rio River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality 36 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 .68 .48 .69 .88 .94 1.59 1.43 1.99 1.05 1.3 1.49 1.8 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) 20.87 < 0.4 Perchlorate concentration 1130 1130 1100 1100 1230 0830 1400 1406 1300 1302 1400 1401 0820 1420 1030 0930 1000 1000 1400 1500 1000 1000 1400 1400 1200 1000 1000 1400 1400 hour) Sample time (24 year) 07/27/2004 08/15/2004 09/03/2004 09/03/2004 08/14/2004 08/14/2004 09/02/2004 09/02/2004 08/16/2004 08/16/2004 08/17/2004 07/14/2004 07/13/2004 10/12/2004 07/14/2004 07/15/2004 08/17/2004 08/19/2004 07/16/2004 07/15/2004 08/20/2004 07/15/2004 08/18/2004 08/18/2004 08/17/2004 07/14/2004 08/19/2004 07/14/2004 07/16/2004 (month/day/ Sample date USGS HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW Project SWTREND SWTREND SWTREND SWTREND

NAWQA NAWQA USGS COOP NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS Program EPALIPS/ EPALIPS/ ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate replicate replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type Site name Rush Creek above Mouth near Rush City, MN Rush Creek above Mouth near City, Devil Creek near Morristown, MN Creek near Belvidere Mills, MN Wells MN Weaver, Creek near Trout Whitman, MN Creek near Valley Deering Whitman, MN Creek near Valley Deering Duschee Creek above Lanesboro, MN Duschee Creek above Lanesboro, MN MO River near Luray, Wyaconda MO River near Luray, Wyaconda Bear Creek at 29th Street Hannibal, MO MT River at State Line near Decker, Tongue Maple Creek near Nickerson, NE Maple Creek near Nickerson, NE NE Waterloo, Elkhorn River at Platte River at Louisville, NE 2N 11W15CDDD1 3N 4W15DADA1 4N 2E25ADAA1 4N 5W18DAAA1 4N 1E 8DDDD1 5N 3W32DCDC1 5N 14W26DDDD1 6N 14W28DDCD1 7DDDC1 6N 10W 7N 5W21CDAD1 7N 14W20DADA1 7N 4W10CCCB1 7N 3E12ADDD1 Site number 05339721 05351400 05355307 05377508 05377550 05377550 05384110 05384110 05495850 05495850 05502005 06306300 06800000 06800000 06800500 06805500 400757098325401 401329097444501 401715097083601 401853097550101 401918097195301 402103097404201 402154098512601 402708098534901 402943098284801 403314097532801 403330098545101 403502097460101 403520097013901 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

NE-11 NE-01 NE-01 NE-02 NE-03 NE-04 NE-05 NE-06 NE-07 NE-08 NE-09 NE-10 NE-12 NE-13 NE-14 NE-15 NE-16 MT-01 MN-11 MN-08 MN-09 MN-10 MN-12 MN-12 MN-13 MN-13 MO-01 MO-01 MO-02 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport TANC, Monitoring Network; <, less than] River Surface-Water-Quality Tables 1, 3–6 37 .6 .95 .61 .67 .78 .5 .77 .44 0.7 1.31 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) Perchlorate concentration 1100 1100 1100 1300 1500 1800 1040 1300 1700 1000 1630 1500 1330 1500 1200 1030 1000 1330 1230 1500 1600 1530 1000 1000 1600 hour) Sample time (24 year) 07/29/2004 08/04/2004 08/25/2004 07/20/2004 07/13/2004 07/13/2004 07/20/2004 07/12/2004 07/19/2004 07/13/2004 09/20/2004 08/16/2004 08/16/2004 08/16/2004 09/08/2004 08/17/2004 08/17/2004 08/17/2004 08/18/2004 08/18/2004 08/18/2004 08/17/2004 08/17/2004 08/17/2004 07/19/2004 09/09/2004 08/19/2004 06/14/2004 06/08/2004 (month/day/ Sample date ACT ACT ACT ACT ACT ACT ACT ACT ACT ACT ACT ACT ACT ACT SPLT USGS CNBR HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW Project SEWARD SEWARD

USGS COOP COOP NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA EPALIPS Program ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient Sample type sw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw gw Site type Site name 11N 3W20DCC1 AWT2-71 3W20DCC1 11N 2E22CBBB2 FP4-105 11N 2E22CBBB3 FP4-129 11N 4BAAA1 12N 5W SB01204232CDD 13N 1W25DAAD1 13N 2W20BBBC1 13N 1E18BCCC1 13N 4W10BAAA1 2ADDA1 14N 2W Duck Creek near Colon, NE ACTFS1-1A WELL 5DBAB1 NAWQA 18N 8W ACTFS1-1B WELL 5DBAB2 NAWQA 18N 8W ACTFS1-1C WELL 5DBAB3 NAWQA 18N 8W 18N 7E 6BCCC1 CNBRLUSCR1 DO-24 ACTFS1-2A WELL 5ACDC1 NAWQA 18N 8W ACTFS1-2B WELL 5ACDC2 NAWQA 18N 8W ACTFS1-2C WELL 5ACDC3 NAWQA 18N 8W ACTFS1-3A WELL 5ACAC1 NAWQA 18N 8W ACTFS1-3B WELL 5ACAC2 NAWQA 18N 8W ACTFS1-3C WELL 5ACAC3 NAWQA 18N 8W ACTFS1-4A WELL 5ABDD1 NAWQA 18N 8W ACTFS1-4B WELL 5ABDD2 NAWQA 18N 8W ACTFS1-4C WELL 5ABDD3 NAWQA 18N 8W 19N 38W33DDDA1 6CBCB1 19N 3W 20N 4E 5CCDC1 CNBRLUSCR1 CO-13 21N 2E35ABAA1 CNBRLUSCR1 S-11 21N 25W13ABAA1 24N 44W16DBDB1 Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued Site number 405406097405601 405420097114002 405420097114003 410247097533601 410251102024201 410410097220601 410520097344501 410552097220501 410710097454201 411256097301101 411636096372901 413334096325301 413334096325302 413334096325303 413340096402701 413341096325501 413341096325502 413341096325503 413348096324801 413348096324802 413348096324803 413350096324701 413350096324702 413350096324703 413412101414501 413850097425801 414343096595801 414527097094101 414748100090901 420326102253201 - Table 4. Table

NE-47 NE-48 NE-49 NE-50 NE-51 NE-52 NE-53 NE-54 NE-55 NE-56 NE-57 NE-58 NE-59 NE-60 NE-61 NE-62 NE-63 NE-64 NE-65 NE-66 NE-67 NE-68 NE-69 NE-70 NE-71 NE-72 NE-73 NE-74 NE-75 NE-76 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport TANC, Monitoring Network; <, less than] River Surface-Water-Quality

38 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004 .45 .42 1.57 1.28 1.06 2.06 1.69 6.23 2.7 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) < 0.4 Perchlorate concentration 1115 1100 1100 1100 1140 1100 1100 1200 1000 1000 1300 1230 1210 1200 1500 0800 1205 1305 1020 1030 1040 1010 0910 0930 hour) Sample time (24 year) 06/08/2004 06/23/2004 06/24/2004 06/16/2004 06/16/2004 06/15/2004 06/09/2004 06/03/2004 06/09/2004 07/22/2004 07/22/2004 07/19/2004 07/13/2004 07/29/2004 07/01/2004 07/01/2004 06/30/2004 08/17/2004 08/17/2004 08/17/2004 08/12/2004 08/18/2004 08/09/2004 09/07/2004 09/08/2004 10/20/2004 (month/day/ Sample date USGS HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW HPGW Project SWTREND SWTREND SWTREND SWTREND SWTREND SWTREND

USGS COOP COOP COOP COOP COOP COOP COOP COOP NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA NAWQA EPALIPS EPALIPS EPALIPS Program blank ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw gw gw gw gw gw gw gw gw gw Site type - - - Site name NM NV Vegas, ence near Las NV Vegas, ence near Las NV Vegas, ence near Las Intake near Reno, NV 24N 36W 2DABC1 24N 36W 4ACBB1 24N 37W 25N 20W13ADAC1 26N 39W19ADCB1 2AADB1 27N 43W 28N 36W36CBBB1 29N 37W20DCDA1 32N 27W24ACBB1 1BB 1 33N 28W Taos, Junction Bridge near Taos Rio Grande below Rio Grande at Otowi Bridge, NM Rio Grande at San Felipe, NM Rio Grande at Isleta, NM Archuleta, NM San Juan River near Animas River at Farmington, NM San Juan River at Farmington, NM San Juan River at Shiprock, NM Conflu Wash below Flamingo Wash Vegas Las Conflu Wash below Flamingo Wash Vegas Las Conflu Wash below Flamingo Wash Vegas Las East Fork Carson River near Dresslerville, NV Plant Treatment River at Chalk Bluff Truckee River at Clark, NV Truckee OH Mad River at St. Paris Pike Eagle City, Auglaize River near Fort Jennings, OH Auglaize River near Fort Jennings, OH Site number 420458101270201 420515101363901 420821099351101 421317101540201 422120102175301 422138101282601 422830101411101 424403100253501 425154100342301 08276500 08313000 08319000 08331000 09355500 09364500 09365000 09368000 094196783 094196783 094196783 10309010 10347699 10350500 03267900 04186500 04186500 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

NE-77 NE-78 NE-79 NE-80 NE-81 NE-82 NE-83 NE-84 NE-85 NV-01 NV-01 NV-01 NV-02 NV-03 NV-04 OH-01 OH-02 OH-02 NM-01 NM-02 NM-03 NM-04 NM-05 NM-06 NM-07 NM-08 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface TANC, Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande River Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport Monitoring Network; <, less than] Surface-Water-Quality

Tables 1, 3–6 39 .93 .96 .49 1.41 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 < .4 (μg/L) < 0.4 Perchlorate concentration 1100 0925 1015 1430 1605 0740 0910 1020 0855 1300 1250 0710 0720 0920 0815 1230 1645 0810 hour) Sample time (24 year) 10/06/2004 10/05/2004 10/05/2004 10/04/2004 09/14/2004 09/14/2004 09/13/2004 09/13/2004 09/07/2004 09/08/2004 09/08/2004 09/08/2004 09/09/2004 09/10/2004 08/20/2004 07/14/2004 07/15/2004 07/14/2004 (month/day/ Sample date USGS Project TRIVER TRIVER TRIVER TRIVER

USGS COOP COOP COOP COOP EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS EPALIPS Program ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient ambient replicate Sample type sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw sw Site type Site name Parker Creek near River Falls, WI Parker Creek near River Falls, WI Black Creek near Fairchild, WI Cranberry Creek at Meridean, WI Arland, Silver Creek near WI Soper Creek at Cataract, WI Little La Crosse River near Melvina, WI Branch Baraboo River at Hillsboro, West WI Hawkins Creek at Rockbridge, WI Crooked Creek at Boscobel, WI Rogers Branch near Lancaster, WI Arthur, Little Platte River near WI Arthur, Little Platte River near WI Galena River at Jenkinsville, WI Branch at Monticello, West Little Sugar River WY Crow Creek at Mouth Pahaska, WY River at Monarch, Tongue WY Acme, Goose Creek near WY Acme, Prairie Dog Creek near Site number 05341865 05365962 05367064 05367803 05381441 05382415 054041139 054067125 05407217 05412880 05414133 05414133 05414924 05436361 06279795 06299980 06305700 06306250 - Perchlorate concentrations at selected surface-water and groundwater sites in the United States.—Continued

WI-11 WI-06 WI-07 WI-08 WI-09 WI-10 WI-12 WI-13 WI-14 WI-15 WI-16 WI-16 WI-17 WI-18 WY-01 WY-02 WY-03 WY-04 (figs. 2–9) Map identifi cation number Table 4. Table Federal/State cooperative project; EPALIPS, Assessment program; COOP, Quality Water National groundwater; NAWQA, surface water; gw, [USGS, U.S. Geological Survey; μg/L, micrograms per Liter; sw, Assessment; Ambient Monitoring and Arizona Department of Environmental Quality; GAMA, California Groundwater AZDEQ, network; Trends Water Landscape Indicators project; SWTREND, Surface Study; Water High Plains Regional Ground South Platte River Basin; IAGWM, Iowa Groundwater Monitoring Network; HPGW, UCOL, Upper Colorado River Basin; SPLT, Valley; RIOG, Rio Grande Tongue TRIVER, study; CNBR, Central Nebraska Basins; Transport Agricultural Chemical ACT, City of Seward, Nebraska.; Anthropogenic and Natural Contaminants Study; SEWARD, of Transport TANC, Monitoring Network; <, less than] River Surface-Water-Quality

40 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

Table 5. Summary of perchlorate detections and concentrations in selected states. [μg/L, micrograms per liter; <, less than] Number of samples Percent of samples Percent of samples Percent of samples Maximum Number of with detectable con- State with concentration with concentration with concentration concentration samples centration (0.4 μg/L or 1.0 μg/L or greater 2.0 μg/L or greater 5.0 μg/L or greater (μg/L ) greater) Surface water Arizona 11 1 0 0 0 0.6 Arkansas 3 1 0 0 0 .68 California 3 2 0 0 0 .87 Colorado 17 1 0 0 0 .63 Illinois 17 0 0 0 0 <.4 Indiana 15 3 13 0 0 1.58 Iowa 30 7 3 0 0 1.12 Michigan 8 1 0 0 0 .85 Minnesota 14 4 14 7 0 2.53 Missouri 2 0 0 0 0 <.4 Montana 1 1 0 0 0 .68 Nebraska 6 1 0 0 0 .48 Nevada 4 1 25 25 25 6.23 New Mexico 8 3 38 12 0 2.06 Ohio 15 3 20 0 0 1.58 South Dakota 3 0 0 0 0 <.4 Texas 3 0 0 0 0 <.4 Wisconsin 18 4 6 0 0 1.41 Wyoming 4 1 0 0 0 .49 Groundwater Arkansas 1 1 0 0 0 .92 California 8 4 13 0 0 1.93 Colorado 21 5 19 9 0 4.19 Iowa 38 9 11 0 0 1.73 Nebraska 80 45 31 6 1.25 20.9

Table 6. Perchlorate concentrations in streams sampled twice during the reconnaissance study. Map identifica- Sample date Sample time (24 Perchlorate concen- tion number Site number Site name (month/day/ hours) tration (ug/L) (figs. 2–9) year) IL-01 05525500 Sugar Creek at Milford, IL 08/06/2004 1005 <0.4 IL-01 05525500 Sugar Creek at Milford, IL 12/15/2004 1245 <.4 IL-02 05572000 Sangamon River at Monticello, IL 08/05/2004 1330 <.4 IL-02 05572000 Sangamon River at Monticello, IL 10/05/2004 0915 <.4 MN-04 05320270 Little Cobb River near Beauford, MN 08/23/2004 1310 .8 MN-04 05320270 Little Cobb River near Beauford, MN 10/07/2004 1005 <.4 NE-01 06800000 Maple Creek near Nickerson, NE 07/13/2004 1030 <.4 NE-01 06800000 Maple Creek near Nickerson, NE 10/12/2004 0930 <.4 OH-02 04186500 Auglaize River near Fort Jennings, OH 09/08/2004 1100 <.4 OH-02 04186500 Auglaize River near Fort Jennings, OH 10/20/2004 0930 <.4 Appendix 42 Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

Appendix 1. Project support. Core funding was provided by the U.S. Geological Survey's Central Region Integrated Science Program. Collection of samples from such a large part of the United States was only possible because of the willingness of personnel working on Federal/State cooperative (COOP) projects, the National Water-Quality Assessment program (NAWQA) , and U.S. Geological Survey/ U.S. Environmental Protection Agency Landscape Indicators (EPALIPS) project to collect an additional water sample. Collection of perchlorate samples was supported as part of the following programs. Federal/State Cooperative Program Water Science Center Project/cooperator Description Arkansas Master well monitoring Arizona Arizona Department of Environmental Quality (AZDEQ) California Groundwater Ambient Monitoring and An assessment of groundwater quality in areas where Assessment (GAMA)/California public supply wells are an important source of drink- State Water Resources Control Board ing water (Wright and others, 2005). Perchlorate samples are routinely analyzed by a commercial laboratory as part of the GAMA project, but additional samples were collected for this study. Colorado Water Quality in the Arkansas River Monitoring in the Fountain and Monument Creek wa- basin near Pueblo, CO/ Southeastern tersheds from 1981 through 2006 to evaluate the ef- Colorado Water Activity Enterprise fects of stormflow and wastewater-treatment effluent on Fountain and Monument Creeks in the Colorado Springs, Colorado area. (Mau and others, 2007) Iowa Iowa Groundwater Monitoring Net- 38 of 150 municipal supply wells completed in shallow work (IAGWM) /Iowa Department alluvial deposits that are susceptible to contamina- of Natural Resources tion from land surface were sampled for perchlorate. (Littin, 2004) Montana Tongue River Surface-Water-Quality Monitoring surface water within or near the Powder Monitoring Network (TRIVER) River structural basin in northeastern Wyoming and southeastern Montana to characterize water quality in streams draining an area of coalbed natural gas development. (Clark and Mason, 2007) Nebraska City of Seward (SEWARD) A study of groundwater age and quality was conducted to improve understanding of: (1) travel times from recharge areas to public-supply wells, (2) the effects of geochemical reactions in the aquifer on water quality, and (3) how water quality has changed his- torically in response to land-use practices. (Stanton and others, 2007) New Mexico Statewide monitoring

National Water-Quality Assessment Program (NAWQA) Topical Study Study Unit Description Surface-WaterTrends (SWTREND) Central Arizona Basins Ambient resource assessment over decades with a Central Nebraska Basins (CNBR) regional and national perspective to evaluate eco- logical conditions and the occurrence, trends, and Eastern Iowa Basins transport of nutrients and pesticides in rivers and Nevada Basin and Range streams. Twenty-five surface-water sites on both Ozark Plateaus medium-sized rivers indicative of a single land use and large rivers that integrate the effects of agricul- Rio Grande (RIOG) tural and urban land use. Santa Ana Appendix 43

Appendix 1. Project support.—Continued Core funding was provided by the U.S. Geological Survey's Central Region Integrated Science Program. Collection of samples from such a large part of the United States was only possible because of the willingness of personnel working on Federal/State cooperative (COOP) projects, the National Water-Quality Assessment program (NAWQA) , and U.S. Geological Survey/ U.S. Environmental Protection Agency Landscape Indicators (EPALIPS) project to collect an additional water sample. Collection of perchlorate samples was supported as part of the following programs. National Water-Quality Assessment Program (NAWQA)—Continued Topical Study Study Unit Description Agricultural Chemical Transport Central Nebraska Basins A study to (1) understand the links between the sources (ACT) of water and agricultural chemicals (nutrients and pesticides) and their behavior and transport through the environment; (2) predict the behavior and transport of water and agricultural chemicals in other agricultural areas not being studied; and (3) evaluate what the study results mean for management of water and water quality in a variety of agricultural settings. (Fredrick and others, 2006) Transport of Anthropogenic and Natu- Central Nebraska Basins Study of the hydrogeology and geochemistry of the ral Contaminants Study (TANC) High Plains aquifer in a 42-square-mile study area at York, Nebraska that contains the zone of contribution to a public supply well (PSW). Data were used to describe factors controlling the transport of selected anthropogenic and natural contaminants to PSWs. (Landon and others, 2008) Groundwater trends South Platte River Basin Topical Study Description High Plains Regional Ground Water Water quality of the High Plains aquifer was assessed for the period 1999-2004 through a strati- Study (HPGW) fied, nested group of studies designed to assess linkages between the quality of water recharg- ing the aquifer, the effect of transport through the hydrologic system on water quality, and the quality of the resource used for human consumption and agricultural applications. (McMahon and others, 2007) USGS/USEPA Landscape Indicators Project (EPALIPS) Water Science Centers Description Illinois, Indiana, Iowa, Michigan, There were 110 third order streams draining agricultural watersheds in 10 corn-belt States that Minnesota, Missouri, Nebraska, were sampled in September 2004 during base flow when most streamflow was derived from Ohio, South Dakota, Wisconsin groundwater discharge. Samples collected at base flow integrated the water quality of a watershed over temporal and geographical scales.

Publishing support provided by: Rolla Publishing Service Center For more information concerning this publication, contact: Director, USGS Iowa Water Science Center 400 South Clinton Street, Room 269 Iowa City, IA 52240 (319) 337–4191 Or visit the Iowa Water Science Center Web site at: http://ia.water.usgs.gov

Kalkhoff and others—Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004—Data Series 495