Concentrations of selected metals in Quaternary-age fluvial deposits along the lower Cheyenne and middle Belle Fourche Rivers, western South Dakota, 2009-10
The headwaters of the Cheyenne and Belle Fourche Rivers drain the Black Hills of South Dakota and Wyoming, an area that has been affected by mining and…
Public-domain full text preserved in the Mountain Man Mining Library. Original source: pubs.usgs.gov.
U.S. Department of the Interior U.S. Geological Survey Data Series 695 Prepared in cooperation with the Cheyenne River Sioux Tribe Concentrations of Selected Metals in Quaternary-Age Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers, Western South Dakota, 2009–10 Prepared in cooperation with the Cheyenne River Sioux Tribe Concentrations of Selected Metals in Quaternary-Age Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers, Western South Dakota, 2009–10
Front cover. Background: Flood-plain deposits from the bank of the Belle Fourche River at site BF4.
Center right: Sampling activities at the Trask Road reference site along the Cheyenne River.
Center left: Subsurface coring on the Belle Fourche River at site BF3. Back cover. View north of the Cheyenne River from the Hump Flat reference site.
Concentrations of Selected Metals in Quaternary-Age Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers, Western South Dakota, 2009–10 By John F. Stamm and Galen K. Hoogestraat Prepared in cooperation with the Cheyenne River Sioux Tribe Data Series 695 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: 2012 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit ://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit ://www.usgs.gov/pubprod To order this and other USGS information products, visit ://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Stamm, J.F., and Hoogestraat, G.K., 2012, Concentrations of selected metals in Quaternary-age fluvial deposits along the lower Cheyenne and middle Belle Fourche Rivers, western South Dakota, 2009–10: U.S. Geological Survey Data Series 695, 29 p.
Acknowledgments The authors would like to acknowledge the Cheyenne River Sioux Tribe, private land owners at sample sites, and the U.S. Army Corps of Engineers for their assistance and support. The National Association of Geological Teachers provided partial funding for a summer student intern in 2009.
Figures
1. Map showing location of the Cheyenne and Belle Fourche River Basins 3
2. Maps showing location of reference sites and sampling locations 8
3. Map showing location of the middle Belle Fourche River potentially contaminated site and sampling locations 10
4. Maps showing sampling locations for transects, subsurface cores, and bank exposures at the middle Belle Fourche River potentially contaminated site 11
5. Map showing sampling locations for transects and bank exposures at the lower Cheyenne River potentially contaminated site 12
6. Cross-sectional profiles of land-surface elevations and arsenic concentrations in surface and subsurface sediment samples from transects on the middle Belle Fourche River 25
7. Cross-sectional profiles of land-surface elevations and arsenic concentrations in surface sediment samples from transects on the lower Cheyenne River 26
8. Cross-sectional profiles of land-surface elevations and mercury concentrations in surface and subsurface sediment samples from transects on the middle Belle Fourche River 27
9. Cross-sectional profiles of land-surface elevations and mercury concentrations in surface sediment samples from transects on the lower Cheyenne River 28 Contents Acknowledgments iii Abstract 1 Introduction 1 Sediment Discharges from Milling Operations 2 The Water Resources Development Act 2 Purpose and Scope 4 Study Design 5 Sampling Sites 5 Sediment Sampling at Reference Sites 6 Sediment Sampling at Potentially Contaminated Sites 6 Sampling Equipment 9 Sample Collection 9 Sample Analysis 13 Quality Assurance 13 Concentrations of Selected Metals in Sediment 15 References Cited 29 Supplemental Data Tables 31
Tables
1. List of metals analyzed in sediment samples and reporting levels 5
2. Reference site descriptions 7
3. Potentially contaminated site descriptions 9
4. Relative percent difference statistics for concentrations of selected metals for sequential replicate and split duplicate sediment samples 14
5. Comparison of mean arsenic concentrations in control samples analyzed by TestAmerica Laboratories and the U.S. Geological Survey Crustal Imaging and Characterization Team 15
6. Summary statistics for concentrations of selected metals in sediment samples from reference sites 16
7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification 17
8. Mean concentrations of arsenic and mercury in sediment samples from reference and potentially contaminated sites reported in four different studies 24 Conversion Factors SI to Inch/Pound Multiply By To obtain Length centimeter (cm) inch (in.) millimeter (mm) inch (in.) meter (m) foot (ft) kilometer (km) mile (mi) Volume cubic meters (m3) cubic yards (yd3) liter (L) gallon (gal) Mass gram (g) ounce, avoirdupois (oz) kilogram (kg) pound avoirdupois (lb) metric ton ton Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Elevation, as used in this report, refers to distance above the vertical datum. Concentrations of chemical constituents in sediment are given either in milligrams per kilogram (mg/kg) or micrograms per kilogram (µg/kg).
Acronyms and Abbreviations As arsenic carbon CBFRS Cheyenne and Belle Fourche River sediment CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980 [CH3Hg]+ methyl mercury [CN]- cyanide anion Cr chromium Fe iron FeAsS arsenopyrite GPS global positioning system H hydrogen Hg mercury lidar Light Detection And Ranging N nitrogen Pb lead RPD relative percent difference S sulfur Se selenium USACE U.S. Army Corps of Engineers USEPA U.S. Environemental Protection Agency USGS U.S. Geological Survey WRDA Water Resources Development Act Zn zinc
Concentrations of Selected Metals in Quaternary-Age Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers, Western South Dakota, 2009–10 By John F. Stamm and Galen K. Hoogestraat Abstract The headwaters of the Cheyenne and Belle Fourche Rivers drain the Black Hills of South Dakota and Wyoming, an area that has been affected by mining and ore-milling operations since the discovery of gold in 1875. A tributary to the Belle Fourche River is Whitewood Creek, which drains the area of the Homestake Mine, a gold mine that operated from 1876 to 2001. Tailings discharged into Whitewood Creek contained arsenopyrite, an arsenic-rich variety of pyrite associated with gold ore, and mercury used as an amalgam during the gold-extraction process. Approximately 18 percent of the tailings that were discharged remain in fluvial deposits on the flood plain along Whitewood Creek, and approximately 25 percent remain in fluvial deposits on the flood plain along the Belle Fourche River, downstream from Whitewood Creek. In 1983, a 29-kilometer (18-mile) reach of Whitewood Creek and the adjacent flood plain was included in the U.S. Envi ronmental Protection Agency’s National Priority List of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, commonly referred to as a “Superfund site.” Listing of this reach of Whitewood Creek was primarily in response to arsenic toxicity of fluvial deposits on the flood plain. Lands along the lower Cheyenne River were trans ferred to adjoining States and Tribes in response to the Water Resources Development Act (WRDA) of 1999. An amendment in 2000 to WRDA required a study of sediment contamination of the Cheyenne River. In response to the WRDA amendment, the U.S. Geological Survey completed field sampling of reference sites (not affected by mine-tailing disposal) along the lower Belle Fourche and lower Cheyenne Rivers. Reference sites were located on stream terraces that were elevated well above historical stream stages to ensure no contamination from historical mining activity. Sampling of potentially contaminated sites was performed on transects of the active flood plain and adjacent terraces that could poten tially be inundated during high-flow events. Sampling began in 2009 and was completed in 2010. A total of 74 geochemical samples were collected from fluvial deposits at reference sites, and 473 samples were collected from potentially contaminated sites. Sediment samples collected were analyzed for 23 met als, including arsenic and mercury. Sequential replicate, split duplicate, and field quality-control samples were analyzed for quality assurance of data-collection methods. The metal concentrations in sediment samples and location information are presented in this report in electronic format (Microsoft Excel), along with non-parametric summary statistics of those data. Cross-sectional topography is graphed with arsenic and mercury concentrations on transects at the potentially con taminated sites. The mean arsenic concentration in reference sediment samples was 8 milligrams per kilogram (mg/kg), compared to 250, 650, and 76 mg/kg for potentially contami nated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively. The mean mercury concentration in reference sediment samples was 16 micrograms per kilogram (µg/kg), compared to 130, 370, and 71 µg/kg for potentially contami nated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively. Introduction The headwaters of the Cheyenne River include the Black Hills of South Dakota and Wyoming (fig. 1). The Belle Fourche River is a major tributary of the Cheyenne River and drains the northern Black Hills. The headwaters of the Belle Fourche River have been affected by mining and ore-milling operations since the discovery of gold near Deadwood, South Dakota, in 1875 (Goddard, 1989). A headwater tributary of the Belle Fourche River is Whitewood Creek (fig. 1), which drains the area of the Homestake Mine, a gold mine that operated from 1876 to 2001 (Mitchell, 2009). Milling operations at the Homestake Mine produced a concentrate of ores that contain arsenic (As), chromium (Cr), lead (Pb) and zinc (Zn), among others (Caddey and others, 1991). Gold ore is associated with
2 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers the mineral arsenopyrite (FeAsS), which is rich in iron (Fe), arsenic, and sulfur (S). Caddey and others (1991) estimated that Homestake ore had as much as 60,500 milligrams per kilogram (mg/kg) of arsenic, primarily in the form of arse nopyrite, although the ore probably contained an average concentration of about 25,000 mg/kg arsenic. The gold extrac tion process utilized mercury (Hg) and an anion of carbon (C) and nitrogen (N) known as cyanide ([CN]-), which were discharged as milling waste with mine tailings into White wood Creek, until December of 1970, when this practice was discontinued (Goddard, 1989). Sediment Discharges from Milling Operations The U.S. Environmental Protection Agency (1973) estimated that approximately 2,700 metric tons of suspended solids were discharged from milling operations into White wood Creek on a daily basis in June 1971, and this may have been a typical discharge during the period of modern mining operations, since about 1920. The U.S. Environmental Protec tion Agency (1971) estimated that 5 to 18 kilograms (kg) of mercury per day were discharged into Whitewood Creek in 1970. Marron (1992) estimated that a total of approximately 110,000,000 metric tons of mining and milling wastes from gold-mining activities were discharged into Whitewood Creek from 1876 through 1977. Of that total, nearly 18 percent of the discharged mine tailings remain stored in fluvial sediment on the flood plain along Whitewood Creek, and 25 percent remain stored farther downstream in fluvial deposits on the flood plain of the Belle Fourche River downstream from its confluence with Whitewood Creek (Marron, 1992). The amount of mine tailings farther downstream in fluval deposits on the flood plain of the lower Cheyenne River and Lake Oahe (fig. 1) is uncertain. Transport of mine tailings farther downstream by the Missouri River was contained after completion of Oahe Dam around 1960. Discharges of mine tailings into Whitewood Creek ceased in 1977, at which point tailings were discharged into a storage facility (Mitchell, 2009). Toxic effects of arsenic in fluvial deposits on the flood plain along Whitewood Creek became a concern in 1974–75 with the death of 50 Holstein dairy cattle as a result of arse notoxicity (Goddard, 1989). Bergeland and others (1976) concluded that those cattle consumed corn silage that was contaminated with mining wastes. In 1983, a 29-kilometer (km; 18-mile) reach of Whitewood Creek and the adjacent flood plain was included in the U.S. Environmental Pro tection Agency (USEPA) National Priority List under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Remedial activities at this site included the removal of approximately 3,400 cubic meters of contaminated soil from 16 residential areas, disposal of contaminated soil in an undeveloped part of the site, and continued surface-water monitoring. Remedial activities were completed in 1993. The site was removed from the USEPA National Priority List in 1996 (U.S. Environmental Protection Agency, 2011a). Results of studies by the U.S. Geological Survey (USGS) of the geochemistry of sediment deposited in the flood plain of Whitewood Creek, the Belle Fourche River, and the Cheyenne River are summarized by Goddard (1989). Studies described in that report included estimates of the concentrations of major, minor, and trace elements from 13 fluvial-sediment samples along the Belle Fourche River upstream from White wood Creek that would serve as reference or background samples, and 95 fluvial-sediment samples from Whitewood Creek that were visually identified as being contaminated by mine tailings. Arsenic was determined to be the principal potentially toxic contaminant of those sediment samples. The average arsenic concentration of streambank sediment of the Belle Fourche River upstream from Whitewood Creek was 9 mg/kg (range of 4 to 20 mg/kg). Sediment on Whitewood Creek that was visually identified as contaminated by mine tailings had an average arsenic concentration of 1,900 mg/kg (range of 350 to 8,200 mg/kg). Goddard (1989) collected additional sediment samples to refine estimates of the spatial variability of arsenic con centrations. The 168 channel-sediment samples that were not affected by mine-tailing discharges had an arithmetic mean arsenic concentration of 21 mg/kg and a geometric mean arsenic concentration of 11 mg/kg. Goddard (1989) described a threshold value for contamination as two standard deviations greater than the geometric mean of the arsenic concentration of uncontaminated sediment. Using this approach, a thresh old concentration of contamination of 46 mg/kg arsenic was computed by Goddard (1989) for fluvial sediment of the Belle Fourche and Cheyenne Rivers. Samples also were collected from potentially contaminated sediment on the flood plain along Whitewood Creek, the Belle Fourche River, and the Cheyenne River. A total of 236 samples of potentially con taminated fluvial sediment along Whitewood Creek had an arithmetic mean arsenic concentration of 1,600 mg/kg. Mean arsenic concentrations of potentially contaminated fluvial sediment from the Belle Fourche River decreased from about 1,300 mg/kg near the confluence with Whitewood Creek to about 400 mg/kg near the confluence with the Cheyenne River. Arsenic concentrations as high as 530 mg/kg were measured in samples collected downstream from the confluence of the Cheyenne River with the Belle Fourche River, and averaged about 78 mg/kg. The Water Resources Development Act In 1944, tribal lands in South Dakota along the Missouri and Cheyenne Rivers were acquired by the U.S. Government under the Pick-Sloan Missouri River Basin Program. In 1959, much of that land was flooded upstream from Oahe Dam, built to impound Lake Oahe (fig. 1). The reservoir and surround ing lands have been subsequently managed by the U.S. Army Corps of Engineers (USACE). In 1999, Public Law 106–53,
Introduction 3 Figure 1. Location of the Cheyenne and Belle Fourche River Basins. CHEYENNE RIVER SOUTH DAKOTA Whitewood Creek River MONTANA WYOMING NEBRASKA River Missouri River LAKE OAHE River M ore a u Belle INDIAN RESERVATION River Ch ey e nn e OAHE DAM BLACK HILLS Deadwood HOMESTAKE MINE h e y e n n e F o u r h e CHEYENNE RIVER SOUTH DAKOTA Cheyenne River Basin Belle Fourche River Basin Whitewood Creek River MONTANA WYOMING NEBRASKA River Base from U.S. Geological Survey digital base data Universal Transverse Mercator projection, Zone 14 Missouri River LAKE OAHE 150 KILOMETERS 100° 105° 44° 42° River M ore a u Belle INDIAN RESERVATION River Ch ey e nn e OAHE DAM BLACK HILLS Deadwood HOMESTAKE MINE h e y e n n e 150 MILES F o u r h e
4 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Title VI, authorized the Department of the Interior to hold in trust specified USACE lands and recreation areas around Lake Oahe for use in perpetuity by the Cheyenne River and Lower Brule Sioux Tribes. This public law is cited as the Water Resources Development Act (WRDA), which was amended in 2000 (U.S. Government, 2000). Studies following the enactment of WRDA include ecological and human risk assessments by the U.S. Envi ronmental Protection Agency (2005, 2006) for two exposure areas: the Cheyenne River arm of Lake Oahe, and a reach of the lower Cheyenne River extending downstream from its confluence with the Belle Fourche River to the Cheyenne River arm of Lake Oahe. Reference areas were the Moreau River, Moreau River arm of Lake Oahe, Lake Oahe north of the Cheyenne River arm, and upland stock ponds. The Moreau River flows approximately parallel to and 48 km (30 miles) north of the Cheyenne River (fig. 1). Ecological risk was identified for benthic organisms and semi-aquatic wildlife (birds and mammals), but not for fish, and was associated with selenium, arsenic, and methyl mercury. Human risk was identified for fishermen, particularly for subsistence fisher men. Toxic risk was associated with arsenic (but uncertainty was high) and with methyl mercury for subsistence fishermen. Moreau River sediment had a mean arsenic concentration of 7.3 mg/kg (U.S. Environmental Protection Agency, 2005) with a range from 4.0 to 20 mg/kg, similar to that present in previous studies (for example, U.S. Environmental Protection Agency, 1973; Goddard, 1989) of background concentrations of Cheyenne River sediment. Mercury was detected in less than one-half of all samples from reference and potentially contaminated sites for analyses with high reporting levels (90–280 micrograms per kilogram [µg/kg]). Sediment samples from the Cheyenne River and Cheyenne River arm (of Lake Oahe) was collected at seven locations (U.S. Environmental Protection Agency, 2005). The mean arsenic concentration of Cheyenne River sediment was 60 mg/kg with a range from 19 to 360 mg/kg, and mean arsenic concentration of Chey enne River arm sediment was 24 mg/kg with a range from 8.7 to 62 mg/kg. Engineering-Environmental Management, Inc. (2004) reported metal concentrations in fluvial sediment from USACE lands that were to be transferred to States and Tribes in response to the WRDA legislation. Reference sampling for that report included 10 samples on a terrace approxi mately 76 meters (m) above the submerged channel floor, and approximately 40 m above the lake surface. Both surface and subsurface sediment were analyzed for metals. Mean arsenic concentrations of fluvial sediment on terraces were 14 mg/kg for surface samples and 9.5 mg/kg for subsurface samples (Engineering-Environmental Management, Inc., 2004). Surface and subsurface concentrations of mercury were both 30 µg/kg. Potentially contaminated, valley-bottom deposits had mean arsenic concentrations of 60 mg/kg for surface samples and 85 mg/kg for subsurface samples, with maximum concentrations of 100 mg/kg for surface samples and 440 mg/kg for subsurface samples. The mean mercury concentrations in valley-bottom deposits were 60 µg/kg for surface samples and 70 µg/kg for subsurface samples, with maximum concentrations of 84 µg/kg for surface samples and 300 µg/kg for subsurface samples. In September 2008, the USACE requested that the USGS sample fluvial sediment along the Cheyenne River in response to section 606 (j), subsection 1(A) of the WRDA as amended in 2000 (U.S. Government, 2000). This amendment requires that the Secretary of the Army complete a study of sediment contamination in the Cheyenne River no later than 10 years after the date of enactment of that section of the WRDA. Based on the results from previous reports of sedi ment contamination from mining in the northern Black Hills (such as Goddard, 1989; Marron, 1992), the study of sediment contamination by the Secretary of the Army would include sites on both the Cheyenne and Belle Fourche Rivers. Field surveys and geochemical sampling by the USGS for that study were completed during the summers of 2009 and 2010. In the remainder of this report, the USGS study is referred to as the Cheyenne and Belle Fourche River sediment (CBFRS) study. This report was prepared in cooperation with the Cheyenne River Sioux Tribe. Purpose and Scope The purpose of this report is to describe study design, sample collection, analytical methods, quality control, loca tions and elevations of samples, and laboratory analyses used in the CBFRS study. The scope of this report does not include interpretation of data or findings, geomorphic maps, or esti mates of bank-erosion or bar deposition. The CBFRS study included two parts. The purpose and scope of Part I of the CBFRS study, completed in 2009, was to provide a “reference” for the concentration of metals in fluvial deposits that were not affected by mining activities in the northern Black Hills. Part I included sampling of fluvial deposits on high terraces, elevated well above the high stage recorded at nearby USGS streamgages. The purpose and scope of Part II of the CBFRS study, completed in 2010, was to char acterize the concentration of metals in fluvial deposits poten tially contaminated by mining activities in the northern Black Hills. Sediment samples collected for Part II of the CBFRS study are referred to as “potentially contaminated” samples in this report. In Parts I and II of the CBFRS study, sediment samples were analyzed for 23 metals, including arsenic and mercury. The CBFRS study is distinguished from previous stud ies by Goddard (1989) in that samples were categorized in the framework of geomorphic setting. Geomorphic setting includes descriptors, such as active channel, active flood plain, back channel, or terraces. Multiple terraces were mapped in the study area. Some terraces were sufficiently elevated above the stream channels so that historical inundation by floodwaters may have been infrequent or unlikely. The extent of the channel, flood plain, and terraces along the middle
Study Design 5 Belle Fourche and lower Cheyenne River were mapped at a 1:24,000 scale. Additional sites, not included in this report, were surveyed using ground-based Light Detection And Ranging (lidar) equipment following the 2010 spring flooding event to provide quantitative estimates of volumes of sedi ment eroded from banks or deposited on point bars during that period. Study Design Part I of the CBFRS study included the collection of samples from high terraces or channel sites that were not affected by discharges of mine tailings, which serve as a reference population. These sites are referred to as reference sites in this report. Part II of the study included the collection of sediment samples from sites that were potentially contami nated by discharges of mine tailings from the northern Black Hills. These sites are referred to as potentially contaminated sites in this report. Sediment samples from both reference and potentially contaminated sites were analyzed for 23 metals listed in table 1. Sampling Sites The study design for reference sites included collecting samples from fluvial deposits that were not subject to influx of mine tailings or from terraces that were elevated well above historical streamflow stages, and sites on the Cheyenne River upstream from its junction with the Belle Fourche River (and therefore not affected by discharges from Whitewood Creek). Reference sites on terraces were located 9 to 85 m above the channel, and are best characterized as strath terraces with thin fluvial deposits capping bedrock that is exposed along the ter race riser (eroded edge of the terrace). Fluvial deposits that were sampled at reference sites included gravel beds with lithologies that were consistent with a provenance in the Black Hills (Redden and DeWitt, 2008). Examples of consistent lithologies include limestone (such as Mississippian-age Madison Limestone in plateaus Table 1. List of metals analyzed in sediment samples and reporting levels. [USGS, U.S. Geological Survey; mg/kg, milligrams per kilogram; µg/kg, micrograms per kilogram] Metal USGS parameter code Units Minimum reporting level Most common reporting level Maximum reporting level Antimony mg/kg Arsenic mg/kg Barium mg/kg Beryllium mg/kg Cadmium mg/kg Calcium mg/kg 1,100 Chromium mg/kg Cobalt mg/kg Copper mg/kg Iron mg/kg 1,000 Lead mg/kg Magnesium mg/kg Manganese mg/kg Nickel mg/kg Selenium mg/kg Sodium mg/kg 5,600 Thallium mg/kg Vanadium mg/kg Zinc mg/kg Mercury µg/kg Aluminum mg/kg Potassium mg/kg 3,300 Silver mg/kg
6 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers of the Black Hills), potassium-feldspar rich granite (such as Precambrian-age Harney Peak Granite in the core of the Black Hills), porphyritic rhyolite (as exposed in Tertiary-age intrusives in the northern Black Hills), red quartzite (present in the Cambrian- and Ordovician-age Deadwood Formation) and metamorphic rocks, such as schist and phyllite (pres ent in the Precambrian-age core of the Black Hills). Ages of fluvial deposits on terraces were determined by radiocarbon or optically stimulated luminescence dating techniques. Duller (2008) provides an overview of field and laboratory techniques used for determining the age of sediments based on optically stimulated luminescence. Ages calculated from fluvial deposits on terraces were Quaternary age. The study design for potentially contaminated sites included sediment sampling on transects that span the active flood plain, adjacent terraces, and bank exposures. Two sites downstream from Whitewood Creek were selected: (1) the middle Belle Fourche River site and (2) the lower Cheyenne River site. Field evidence for the designation of active flood plain included observations of inundation in 2008 and 2009, active backwater channels, loose sediment on the surface, blocks of ice on the surface, sediment deposited on top of veg etation (grass), material snagged in vegetation above the soil surface, and presence of driftwood on the surface. Sediment Sampling at Reference Sites Four sites on the lower Cheyenne River (Wasta, Trask Road, Bridger, and Hump Flat) and one site on the middle Belle Fourche River (Volunteer) were selected as reference sites (table 2; fig. 2). Multiple sediment samples were col lected at reference sites from natural exposures (such as head scarps above slump blocks) or from pits excavated by hand shovel or trowel. Sampling locations are shown in figure 2; samples are identified by an abbreviation of the site name followed by other identification (for example, the Volunteer site has two sampling locations identified as VOLU-L1 and VOLU-L2). Locations of exposures or pits were randomly selected from a series of points along the terrace riser. A total of 10 random points were selected and evaluated for suitability in the field before sampling. Examples of attributes that would make a sample location unsuitable include (but were not lim ited to) the following: it was on or near a road or trail, it was over or near a utility line, it was near a previous sample site (within 7.6 m), excavation would affect a fence post, tree, woody brush, building, or other feature that should not be disturbed, the site was previously excavated (base of gravel pit or cattle pond), it was on an inaccessible scarp or has potential for col lapse, the landowner requested excavation at a different loca tion, or archaeological surveys indicated that the site was unac ceptable. Local utilities were contacted to determine that sampling would not threaten utility lines. Selected sampling locations were surveyed using high-precision global positioning system (GPS) equipment. Samples also were collected from active channel bars on transects crossing the Cheyenne River at the Wasta and Trask Road sites (sampling locations TRAS-XS and WAST-XS on fig. 2). At both of those sampling locations, three pit locations on the transects were randomly selected and sampled. Loca tions had to be sufficiently elevated above stream level so that there would be no standing water in each excavated pit. Samples were collected from the surface (upper 10 centimeters [cm] of soil) and subsurface (generally an interval 20 to 40 cm deep), and sampling was completed during low streamflow. These samples were considered to be reference samples in this report because the channel is upstream from the confluence of the Cheyenne and the Belle Fourche Rivers, and therefore upstream from mine-tailing discharges. Sediment Sampling at Potentially Contaminated Sites Two sites were selected for sampling potentially con taminated fluvial deposits (table 3), one on the middle Belle Fourche River (figs. 3 and 4) and one on the lower Cheyenne River (fig. 5). Sediment sampling locations at potentially contaminated sites include those from multiple excavations on transects, subsurface cores (middle Belle Fourche River site only), and bank exposures. Sediment samples collected from excavations on transects included shallow samples (upper 10 cm of soil) at both the middle Belle Fourche River and lower Cheyenne River sites, and subsurface samples (gener ally an interval 20 to 40 cm deep) at only the middle Belle Fourche River site. Transects extended perpendicular from the river channel and included high terraces that were not neces sarily contaminated by mine tailings. Locations of transects were selected to include lateral and point bar depositional environments on the active flood plain. Surfaces with evidence of recent flooding were of particular interest. Sampling loca tions are shown in figures 4 and 5; samples are identified by an abbreviation of the site name (“BF” for middle Belle Fourche River site or “CR” for the lower Cheyenne River site), fol lowed by an abbreviation of the sample type (“GP” for sub surface core or “BK” for bank exposure), followed by other identification. For example, the lower Cheyenne River site (fig. 5) has four bank exposure sampling locations identified as CRBK1, CRBK2, CRBK3, and CRBK4, and three transects identified as CR1, CR2, and CR3. On Belle Fourche River flood-plain transects, excavations were spaced approximately every 6 m, and a hand shovel was used to excavate each pit. At the lower Cheyenne River site,
Study Design 7 Table 2. Reference site descriptions. [USGS, U.S. Geological Survey; m, meters. Elevation, in meters, above North American Vertical Datum of 1988] Site name (abbreviation) Site characteristics Site description Wasta (WAST) Name Cheyenne River terrace above Wasta and channel at USGS streamgage. Elevation Terrace at 77 m above channel and channel/flood plain near streamgage; elevation 774.2 m. Location Terrace deposits exposed in gravel pit adjacent to Elm Springs Road and channel near USGS streamgage. Map description1 Wasta, T. 1 N., R. 14 E., NE¼ of section 5. Land use Gravel mining. Trask Road (TRAS) Name Cheyenne River terrace and channel near Trask Road. Elevation Terrace at 77 m above channel and main channel; elevation 743.7 m. Location West of Trask Road and adjacent channel sediment. Map description1 Wasta NW, T. 14 E., R. 3 N., SW¼ of section 25. Land use Grazing. Bridger (BRID) Name Cheyenne River terrace west of Bridger. Elevation Terrace at 85 m above channel, elevation 658.4 m. Location North of channel on Cheyenne River Indian Reservation land. Map description1 Bridger, T. 7 N., R. 18 E., SE½ of sections 28 and 29. Land use Surface gravel mining, residence of landowner, grazing. Hump Flat (HUMP) Name Cheyenne River terrace on Hump Flat. Elevation Terrace at 85 m above channel, elevation 646.2 m. Location North of channel, east of Route 73/34, 3 miles east of Bridger. Map description1 Bridger SE, T. 7 N., R. 19 E., S½ of sections 28 and 29. Land use Nearby use includes crop production (hay). Volunteer (VOLU) Name Belle Fourche River terrace near Bear Butte Creek and Volunteer. Elevation Terrace at 12 m above channel, elevation 777.2 m. Location South of Route 34, along 146th Avenue. Map description1 Rapid City 1 NE, T. 6 N., R. 8 E, SW¼ of section 11 and NE¼ of section 14. Land use Crop production (hay). 1Map descriptions based on USGS 7.5-minute series 1:24,000-scale topographical maps and Public Land Survey System designation by township (T), range (R), and section. excavations were spaced approximately every 35 m on tran sects. A hand trowel was used for excavation. Elevation and coordinates of excavations at both potentially contaminated sites were surveyed using high-precision GPS equipment. At the middle Belle Fourche River site, subsurface core samples (fig. 4) were collected from cores extracted using a direct push coring device on a transect parallel to, and offset approximately 10 m from, excavated pit transects. In general, cores were extracted to the depth of bedrock (Cretaceous-age Pierre Shale) or to a depth of 4.6 m, whichever was shallower (four subsurface cores were 1.15 m in length). Sediment samples also were collected from bank expo sures at both sites. Locations of bank-exposure samples were selected in the field on the basis of transect proximity and the availability of vertical bank exposure of 0.5 m or greater (to allow for vertical separation of samples). In general, exposures near transects and with underlying, exposed bedrock (Pierre Shale) were preferred, so that the complete fluvial sedimen tary sequence could be described. Elevations and coordinates of bank exposures were surveyed using high-precision GPS equipment.
8 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Figure 2. Location of reference sites and sampling locations. 102°24’ 102°25’30” 102°27’ 44°05’ 44°04’ 102°22’30” 102°24’ 102°25’30” 44°12’ 44°10’30” 103°06’ 103°07’30” 44°30’ 44°29’ 101°51’ 101°54’ 101°57’ 44°34’ 44°32’ 44°30’ CHEYENNE RIVER INDIAN RESERVATION LAKE OAHE Trask Road Wasta Volunteer Bridger/ Hump Flat Belle River River h e y e n ne Whitewood Creek SOUTH DAKOTA OAHE DAM Mi ss ou ri Ri ve r F o u r h e Cheyenne River TRAS-L3 TRAS-XS TRAS-L1 TRAS-L4 WAST-XS WAST-L1 WAST-L2 VOLU-L1 VOLU-L2 BRID-L4 BRID-L3 HUMP-L1 HUMP-L2 HUMP-L3 TRASK ROAD Base from U.S. Geological Survey digital base data Universal Transverse Mercator projection, Zone 13 EXPLANATION Sampling location with sample identification VOLUNTEER TRASK ROAD VOLUNTEER TRASK ROAD BRIDGER BRIDGER HUMP FLAT HUMP FLAT WASTA WASTA 1 KILOMETER 1 MILE 2 KILOMETERS 2 MILES 1 KILOMETER 1 MILE 1.5 KILOMETERS 1.5 MILES TRAS-L3
Study Design 9 Table 3. Potentially contaminated site descriptions. [USGS, U.S. Geological Survey] Site name (abbreviation) Site characteristics Site description Cheyenne River (CR) Name Lower Cheyenne River. Location Channel, flood plain, and terraces along the Cheyenne River, upstream from the Four Corners Road bridge. Map description1 Howes, T. 6 N., R. 17 E., sections 1, 2; T. 7 N., R. 17 E., section 36. Land use Livestock grazing, surface gravel mining. Belle Fourche River (BF) Name Middle Belle Fourche River. Location Channel, flood plain, and terraces along the Belle Fourche River upstream from the South Dakota Highway 34 bridge. Map description1 Volunteer, T. 6 N., R. 8 E., sections 3, 4; T. 7 N., R. 8 E., sections 28, 33, 34. Land use Livestock grazing. 1Map descriptions based on USGS 7.5-minute series 1:24,000-scale topographical maps and Public Land Survey System designation by township (T), range (R), and section. Sampling Equipment Equipment used to collect samples included hand shov els, trowels, plastic bowls (for homogenizing samples), and 0.12-liter (L; 4-ounce) amber glass sample jars (supplied by the analytical laboratory, TestAmerica Laboratories). Shovels, trowels, and bowls used for pit excavation and sampling were cleaned using ALCONOX® liquid detergent and rinsed with distilled water before use. Sampling equipment was wrapped in clean plastic bags and placed in clean tarps in the field until needed for use. Equipment was cleaned after each use, before using on another pit excavation. When available, pre-sterilized and individually packaged (by the supplier) trowels were used for sample collection. Latex gloves and dust masks were used by sampling personnel throughout the sampling process. Sam pling was avoided or terminated if winds were of sufficient strength to transport sediment. The Geoprobe® direct-push coring device (Geoprobe Systems, 2012), lined with a 4-cm diameter by 115-cm length plastic sleeve, protected cores from contamination. New, clean plastic sleeves were used for each core segment. The bit of the coring device was cleaned by hand (with wire brush and water) to remove as much sediment as possible before each core extraction. Sample Collection Samples were collected at reference sites and potentially contaminated sites using similar sample-collection methods. Approximately 1 kg of sediment was collected using a clean trowel and placed into a clean mixing bowl. The sample was then homogenized in the field by stirring thoroughly with a clean trowel. The sample was then shaped into a cone, and the cone was quartered. Subsamples were collected from each quarter until sufficient to fill a 0.12-L (4-ounce) amber glass container, supplied by the analytical laboratory (TestAmerica Laboratories, Denver, Colo.). The same number of subsamples was collected from each quarter so that no one quarter contrib uted more or less subsamples than another quarter. Once suf ficient sample mass was collected (approximately 100 grams), sample jars were capped, labeled (paper label affixed to the jar), and double bagged in resealable bags. A metal tag with the sample number impressed on the tag was placed in the resealable bag. Samples were then stored in ice-filled coolers. Ice in coolers was double bagged to avoid leakage. Samples were shipped overnight with ice. A 0.12-L amber glass con tainer filled with water was included with all ice-filled coolers. The analysis laboratory would measure the temperature of the water in this jar upon delivery of the ice-filled cooler. If the temperature of the water exceeded 6 degrees Celcius, the samples in the cooler would not be used for mercury analyses. At reference sites (but not at potentially contaminated sites), surplus sediment collected (approximately 1 kg) to fill the 0.12-L (4-ounce), amber glass jar was stored in a reseal able bag (double bagged) for possible particle-size analyses and estimate of arsenic concentration for size fractions. Surplus was retained to re-analyze arsenic concentration for particle-size fractions for samples previously identified as having the highest arsenic concentrations. Those samples were shipped to the analytical laboratory in coolers, but were not shipped on ice. As previously described, samples from reference sites were collected from excavated pits along the terrace riser (eroded edge of the terrace) or from natural exposures. Exca vations on the terrace riser were at times sufficiently large to consider replanting of vegetation. At those sites, vegetation was removed in such a manner to save the plant and roots so that it could be replanted upon completion of sample col lection, which typically required 1 day. Upon completion of
10 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Figure 3. Location of the middle Belle Fourche River potentially contaminated site and sampling locations. CHEYENNE RIVER INDIAN RESERVATION LAKE OAHE River h e y e n ne Whitewood Creek Middle Belle Fourche River site SOUTH DAKOTA OAHE DAM Mi ss ou ri Ri ve r Belle River F o u r h e Cheyenne River Base from U.S. Geological Survey digital base data Universal Transverse Mercator projection, Zone 13 103°07’30” 103°09’ 103°10’30” 44°32’ 44°31’ 1 KILOMETER 1 MILE BF4, see fig. 4 BF3, see fig. 4 BF2, see fig. 4 BF1, see fig. 4 BF4, see fig. 4 BF3, see fig. 4 BF2, see fig. 4 BF1, see fig. 4
Study Design 11 Figure 4. Sampling locations for transects, subsurface cores, and bank exposures at the middle Belle Fourche River potentially contaminated site. Base from U.S. Geological Survey digital base data Universal Transverse Mercator projection, Zone 13 EXPLANATION Subsurface core Bank exposure BF4 BF3 BF2 BF1 BF4 BF3 BF2 BF1 GP31 GP32 GP33 GP34 GP14 GP13 GP12 BFBK1 BFBK2 BFBK4 BFBK3 GP44 GP43 GP42 GP24 GP23 GP22 GP21 Transect Sampling location with sample identification 300 METERS 1,000 FEET GP31 BFBK1
12 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Figure 5. Sampling locations for transects and bank exposures at the lower Cheyenne River potentially contaminated site. CHEYENNE RIVER INDIAN RESERVATION SOUTH DAKOTA LAKE OAHE Cheyenne River sites River h e y e n ne Whitewood Creek OAHE DAM Mi ss ou ri Ri ve r Belle River F o u r h e Cheyenne River 102°00’ 102°01’ 44°31’30” 44°30’45” Base from U.S. Geological Survey digital base data Universal Transverse Mercator projection, Zone 13 CR3 CR3 CRBK1 CRBK2 CRBK3 CRBK4 0.4 KILOMETER 0.4 MILE CR2 CR2 CR1 CR1 EXPLANATION Transect Subsurface core sampling location with sample identification CRBK2
Study Design 13 sampling, pits were refilled with the excavated material, veg etation was replanted, and the surface was watered. At natural exposures (such as scarps), the surface was scraped clean so that holes created by sampling were no longer apparent to the casual observer. Methods used to collect samples from subsurface cores differed from those previously described. Subsurface cores were collected in the field using a Geoprobe® coring device. Cores were contained in a plastic sleeve (previously described), which was labeled, capped, sealed, and stored on ice in the field. Cores were transported to the USGS laboratory in Rapid City, S. Dak. At the laboratory, cores were split open using a clean splitter (sharp, hooked blade). Cores were photo graphed, described, and sampled. Five samples were collected from a set of cores for each subsurface core sampling location (which includes as many as four core lengths). Care was taken to collect samples from distinct sedimentary units described in cores. If less than five units were described, then the thickest unit was sampled multiple times. Samples were not homogenized because available sediment generally was less than the volume of the 0.12-L (4-ounce), amber glass jar. Samples were directly transferred to the amber glass jars, stored, and shipped on ice using procedures and protocols as previously described for storage and shipment of homogenized samples. Sample Analysis Sediment samples were submitted to TestAmerica Laboratories (Denver, Colo.) for analysis of metals. Analyses for the concentrations of 23 metals (table 1) were based on U.S. Environmental Protection Agency (2011b) standard methods for solids. Sample preparation and digestion fol lowed USEPA method 3050B. Mercury was analyzed using cold vapor atomic absorption (USEPA method 7471A), and the remaining 22 metals were analyzed using inductively coupled plasma atomic-emission spectrometry (USEPA method 6010B). Moisture content of the samples was determined according to American Society for Testing and Materials (2011) standard D2216. Selected samples col lected for Part I of the CBFRS study were sieved by person nel at TestAmerica Laboratories to separate sand (passing through a 2-millimeter mesh sieve but not passing through a 63-micrometer mesh sieve) from silt/clay fractions (passing through a 63-micrometer mesh sieve). Selected sieved samples were re-analyzed for arsenic concentrations using methods described previously for 22 metals. Quality Assurance Quality-assurance samples, which included sequential replicates, split duplicates, and control samples, were collected to assess the laboratory and environmental variability of metal concentrations. Sequential replicates were collected by resam pling at the same location and depth of a previously collected sample. Sequential replicates are collected in the field and can be used to assess environmental variability of metal concentra tions. Split duplicates are collected in the field and consist of two sub-samples obtained from a sample after homogeniza tion. Split duplicates can assess variability in a homogenized sample and variability associated with laboratory analyses. The relative percent differences (RPDs), which were calcu lated as the absolute difference in concentrations between the environmental and replicate (or duplicate) samples divided by mean concentration of the environmental/replicate (or dupli cate) pair, are shown in table 4 for sequential replicate and split duplicate sample pairs. Large RPDs commonly were the result of small differences at low concentrations. For example, an environmental and replicate sample pair with arsenic concentrations of 14 and 19 mg/kg, respectively, would yield an RPD of 30 percent; however, the same absolute concentra tion difference (5 mg/kg) for a sample pair with an average arsenic concentration of 250 mg/kg would yield an RPD of only 2 percent. Control samples are sediment from a stock container that has been independently analyzed for the suite of 23 metals by the USGS Crustal Imaging and Characterization Team, Denver, Colo. Control samples were from reference and potentially contaminated sediment on the flood plain along the Belle Fourche River near the Volunteer site (VOLU). Three 18.9-L (5-gallon) plastic buckets of sand-to-silt size sediment were collected from the upper 2 m of fluvial sediment on a terrace at site VOLU-L2 (fig. 2). At the height of the terrace (approximately 9 m above the channel), contamination from mine tailings would be unlikely (unless finer particles were transported by wind). Three 18.9-L (5-gallon) plastic buckets of potentially contaminated sediment were collected from red, sandy-silt deposits on the flood plain approximately 90 m upstream from sampling location VOLU-L2. The red color and silty texture is consistent with the color and texture of transported mine tailings (Goddard, 1989). Control samples collected from fluvial sediment depos ited on the terrace and on the flood plain were each separately homogenized by the USGS Crustal Imaging and Characteriza tion Team to provide subsamples with consistent low and high arsenic concentrations, respectively. Subsamples of homogenized terrace and flood-plain samples then were mixed and homogenized to provide subsamples with consistent medium arsenic concentrations. Homogenized sediment was split and stored in plastic bags, each containing approximately 1 kg of sediment. Determination of concentrations of metals at that USGS laboratory were based on USEPA method 3050B diges tion and USEPA method 6010B atomic emission spectrometry (U.S. Environmental Protection Agency, 2011b). Arsenic con centrations were determined to be 14.1 mg/kg, 1,575 mg/kg, and 715 mg/kg for the terrace, flood-plain, and mixed control samples, respectively. Eight control samples were included with batches of reference and potentially contaminated sediment samples sent to TestAmerica Laboratories. Samples were labeled in such a way that they would not be distinguished as control samples. TestAmerica Laboratories was alerted that control samples
14 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Table 4. Relative percent difference statistics for concentrations of selected metals for sequential replicate and split duplicate sediment samples. [Count, number of replicate (duplicate)/environmental sample pairs] Metal Sequential replicates (potentially contaminated sites) Split duplicates (potentially contaminated sites) Sequential replicates (reference sites) Minimum Median Mean Maximum Count Minimum Median Mean Maximum Count Minimum Median Mean Maximum Count Aluminum Antimony Arsenic Barium Beryllium Cadmium Calcium Chromium Cobalt Copper Iron Lead Magnesium Manganese Mercury Nickel Potassium Selenium Silver Sodium Thallium Vanadium Zinc
Concentrations of Selected Metals in Sediment 15 were to be included with submitted sample batches, so that the laboratory could anticipate some samples to be outside the range of concentrations of other samples in a batch. Mean arsenic concentrations in control samples based on analyses by the USGS Crustal Imaging and Characterization Team labora tory and TestAmerica Laboratories were within 10 percent relative difference (table 5). Concentrations of Selected Metals in Sediment A total of 74 sediment samples were collected from flu vial deposits at reference sites (fig. 2), and 473 samples were collected from potentially contaminated sites on the middle Belle Fourche and lower Cheyenne Rivers. At the middle Belle Fourche River potentially contaminated site (figs. 3 and 4), 120 samples were collected from near the surface and 120 samples were collected from the subsurface in excavated pits on 4 transects. In addition, 20 samples were collected from four bank exposures, and 70 samples were collected from 14 subsurface cores collected on a transect parallel to, and offset approximately 10 m from, excavated pit transects. At the lower Cheyenne River potentially contaminated site (fig. 5), 123 samples were collected near the surface on three transects, and 20 samples were collected from 4 bank expo sures. No samples were collected from the subsurface or cores at that site. Metal concentrations in sediment samples and location information are presented in electronic format in the “Supple mental Data Tables” section for reference sites (table S1) and potentially contaminated sites (table S2). Some metal concentrations are reported as estimated values, meaning that either concentrations were greater than the instrument detec tion level but less than the lowest calibration standard, or there were discrepancies in meeting certain analyte-specific quality-control criteria. Non-parametric summary statistics are presented in table 6 for the sediment samples from reference sites and in table 7 for sediment samples from potentially con taminated sites. Results for potentially contaminated samples are summarized according to the nearest transect (figs. 4 and 5; table S2) and relative depth (at or below the surface). Samples from bank exposures that were not near a transect are summarized separately. For context, table 8 presents mean arsenic and mercury concentrations for samples from refer ence and potentially contaminated sites reported in previous studies and the CBFRS. The mean arsenic concentration in reference sediment samples was 8 mg/kg, compared to 250, 650, and 76 mg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively (table 8). The mean mercury concentration in reference sediment samples was 16 µg/kg, compared to 130, 370, and 71 µg/kg for potentially contaminated sediment samples at the surface of the middle Belle Fourche River site, the subsurface of the middle Belle Fourche River site, and the surface of the lower Cheyenne River site, respectively (table 8). Cross-sectional profiles of land-surface elevations and arsenic concentrations in sediment samples from transects at the potentially contaminated sites are shown in figure 6 for the middle Belle Fourche River and in figure 7 for the lower Cheyenne River. Cross-sectional profiles of land-surface ele vations and mercury concentrations in sediment samples are shown in figures 8 and 9 for the middle Belle Fourche River and lower Cheyenne River, respectively. Sample elevations as shown in figures 6–9 are listed in table S2. Cross-sectional profiles are oriented as if looking in the downstream direc tion. The cross-sectional profiles for the middle Belle Fourche River include arsenic concentrations from both surface and subsurface samples. A line indicating the maximum concentra tions of arsenic (34 mg/kg) and mercury (66 µg/kg) at refer ence sites are included in the cross-sectional profiles. Table 5. Comparison of mean arsenic concentrations in control samples analyzed by TestAmerica Laboratories and the U.S. Geological Survey Crustal Imaging and Characterization Team. [Concentrations are in units of milligrams per kilogram. USGS, U.S. Geological Survey] Control sample with relative arsenic concentration Number of samples Mean arsenic concentration Mean relative percent difference TestAmerica USGS Control 1—low Control 2—medium Control 3—high 1,533 1,575
16 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Table 6. Summary statistics for concentrations of selected metals in sediment samples from reference sites. [Moisture content is in percent; concentrations for metals are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, esti mated value1] Property/metal Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony
E0.8 Arsenic E34 Barium E48 Beryllium E0.20 Cadmium E0.10 Calcium 4,300 8,600 14,000 18,000 86,000 Chromium E1.5 Cobalt Copper E2 Iron 6,500 10,000 15,000 19,000 E52,000 Lead Magnesium 1,100 1,400 2,850 7,300 Manganese E120 E1,600 Nickel E2.9 Selenium Sodium 4,500 Thallium <16 Vanadium Zinc Mercury <31 Aluminum 1,200 1,900 2,750 5,675 E15,000 Potassium 1,075 6,000 Silver
1Some metal concentrations are reported as estimated values, meaning either concentrations were greater than the instrument detection level but less than the lowest calibration standard, or there were discrepancies in meeting certain analyte-specific quality-control criteria.
Concentrations of Selected Metals in Sediment 17 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification. [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1] Property/ metal BF1 BF1-sub Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E0.53 Arsenic 1,500 4,200 Barium Beryllium E0.22 E0.87 Cadmium E0.026 E0.075 E0.10 E0.13 E0.24 E0.046 E0.18 Calcium 5,200 8,300 9,100 10,000 21,000 3,600 7,100 8,400 11,000 35,000 Chromium Cobalt Copper Iron 17,000 23,000 25,000 26,000 30,000 17,000 26,000 33,000 69,000 110,000 Lead Magnesium 3,300 4,600 5,100 5,300 6,300 1,900 5,300 5,800 6,600 17,000 Manganese 1,400 3,600 Nickel Selenium E0.50 E0.61 E0.79 E1.2 E0.67 E1.2 E2 Sodium E90 E140 E170 E250 2,500 E170 E220 2,000 Thallium E0.39 Vanadium Zinc Mercury E19 E9.1 3,000 Aluminum 6,500 9,100 9,800 11,000 13,000 5,500 10,000 12,000 13,000 20,000 Potassium 1,100 1,500 1,600 1,900 2,300 1,800 2,900 Silver E0.11 E0.18 E0.16 E0.63 E1.2
18 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Property/ metal BF2 BF2-sub Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E0.97 Arsenic 2,200 Barium Beryllium Cadmium E0.036 E0.15 E0.13 Calcium 2,600 6,600 9,100 9,650 20,000 1,500 4,350 7,600 12,000 19,000 Chromium Cobalt Copper Iron 15,000 24,000 25,000 29,000 38,000 11,000 24,500 36,000 41,000 78,000 Lead Magnesium 1,800 4,300 4,900 5,900 2,700 3,800 4,500 5,400 13,000 Manganese 3,000 Nickel Selenium E0.82 E0.94 E1.1 E1.6 E0.51 Sodium E42 E76 E100 E110 E52 E81 E100 E145 2,500 Thallium E0.5 Vanadium Zinc Mercury E22 E8 2,400 Aluminum 5,300 7,800 8,600 9,950 11,000 2,700 7,100 8,100 9,800 19,000 Potassium 1,400 1,600 1,800 1,900 2,400 1,500 1,600 1,800 3,200 Silver E0.12 E0.16 E0.23 E0.34 E0.14 E0.36 E0.45 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
Concentrations of Selected Metals in Sediment 19 Property/ metal BF3 BF3-sub Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E0.33 E0.33 Arsenic 3,100 Barium Beryllium E0.18 Cadmium E0.11 Calcium 2,300 6,725 8,250 8,800 11,000 2,500 6,000 8,050 11,000 44,000 Chromium Cobalt Copper Iron 24,000 25,000 29,000 35,750 39,000 21,000 33,000 44,000 49,750 95,000 Lead Magnesium 3,900 4,900 5,300 5,650 6,600 2,200 3,825 5,150 5,875 18,000 Manganese 4,000 Nickel Selenium E1.0 E0.47 E0.87 Sodium E67 E91 E100 E110 E200 E43 E110 E140 E245 1,100 Thallium E0.42 Vanadium Zinc Mercury E12 2,400 Aluminum 6,700 9,025 9,900 10,000 14,000 3,600 7,925 9,650 12,000 20,000 Potassium 1,625 1,850 2,000 2,600 1,400 1,650 2,000 3,200 Silver E0.13 E0.18 E0.22 E0.34 E0.14 E0.37 E0.52 E0.73 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
20 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Property/ metal BF4 BF4-sub Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E0.24 E0.22 Arsenic 3,200 Barium Beryllium Cadmium E0.27 E0.047 E0.2 Calcium 1,400 8,000 9,150 10,750 14,000 1,700 5,025 8,650 11,000 21,000 Chromium Cobalt Copper Iron 24,000 27,250 30,000 33,000 44,000 13,000 24,000 37,500 43,000 100,000 Lead Magnesium 3,400 5,000 5,300 5,475 5,900 2,825 3,650 4,750 10,000 Manganese 2,500 Nickel Selenium E0.84 E1.1 E1.2 E1.4 E0.48 E1.3 E1.6 Sodium E49 E80 E92 E97 E180 E46 E72 E90 E100 1,300 Thallium Vanadium Zinc Mercury 2,800 Aluminum 7,300 11,000 11,000 12,000 13,000 1,300 4,900 7,900 9,950 16,000 Potassium 1,600 2,000 2,100 2,200 2,600 1,600 1,875 3,300 Silver E0.21 E0.24 E0.29 E0.37 E0.55 E0.22 E0.48 E0.58 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
Concentrations of Selected Metals in Sediment 21 Property/ metal BFBK1-2 CR1 Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E1.4 E0.88 Arsenic 1,675 3,000 Barium Beryllium E0.22 E0.39 E0.42 E0.21 Cadmium E0.11 E4.5 E0.079 E0.14 E0.18 E0.23 Calcium 2,500 7,825 10,500 12,000 16,000 7,100 10,000 11,000 13,000 33,000 Chromium E3 Cobalt Copper E 4.5 Iron 14,000 38,500 70,000 77,250 130,000 13,000 21,000 23,000 24,750 46,000 Lead Magnesium 1,100 4,975 5,300 6,900 14,000 1,950 4,350 6,875 8,100 Manganese 1,350 1,575 3,500 4,100 Nickel Selenium E1.4 E1.8 E2.6 E0.53 E0.76 Sodium E57 E82 E160 1,600 E65 E110 E150 E198 Thallium E0.62 Vanadium Zinc Mercury E14 1,065 3,000 E28 Aluminum 1,600 9,050 9,900 11,000 22,000 4,100 8,150 14,000 18,000 Potassium 1,850 2,050 2,600 3,600 1,800 2,700 3,200 Silver E0.26 E0.63 E0.83 E0.88 E0.57 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
22 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Property/ metal CR2 CR3 Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony E0.82 E0.36 Arsenic Barium Beryllium E0.11 Cadmium E0.074 E0.15 Calcium 6,000 8,500 11,000 14,000 17,000 4,200 7,800 12,000 14,000 16,000 Chromium Cobalt Copper Iron 6,900 22,000 23,000 24,000 27,000 12,000 20,000 22,000 24,500 28,000 Lead Magnesium 5,050 5,900 6,675 7,500 1,600 4,400 5,800 6,400 7,800 Manganese 1,000 Nickel Selenium E0.76 E1.2 E0.66 Sodium E39 3,000 E64 E160 E230 2,400 Thallium Vanadium Zinc Mercury E17 Aluminum 9,625 11,500 14,000 18,000 3,100 8,700 12,000 14,000 19,000 Potassium 2,200 2,500 2,775 3,400 2,050 2,900 4,000 Silver E0.12 E0.1 E0.13 Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
Concentrations of Selected Metals in Sediment 23 Property/ metal CRBK1-2 CRBK3-4 Minimum 25th percentile Median 75th percentile Maximum Number of samples Minimum 25th percentile Median 75th percentile Maximum Number of samples Moisture content Antimony Arsenic Barium Beryllium E0.16 E0.37 E0.42 E0.46 E0.38 E0.40 E0.46 E0.52 Cadmium E0.096 E0.20 E0.28 E0.32 E0.36 E0.25 E0.32 E0.37 Calcium 9,900 11,250 13,000 13,000 16,000 13,000 14,000 15,000 15,750 20,000 Chromium E2.5 Cobalt Copper E3.6 Iron 9,600 16,250 17,500 18,750 22,000 16,000 22,000 23,000 29,250 46,000 Lead Magnesium 3,450 3,800 4,175 4,500 3,300 3,750 4,600 6,125 7,100 Manganese 1,200 Nickel Selenium E0.44 E0.52 E0.59 E0.89 E0.46 E0.62 E0.88 E1.5 Sodium E90 E230 E315 E365 1,200 Thallium Vanadium Zinc Mercury E10 Aluminum 1,300 6,050 7,200 8,200 10,000 6,400 7,500 9,100 12,000 13,000 Potassium 1,425 1,750 1,875 2,200 1,400 1,725 2,300 2,450 2,900 Silver E0.08 E0.18 E0.09 E0.11 E0.16 E0.30 1Some metal concentrations are reported as estimated values, meaning either concentrations were greater than the instrument detection level but less than the lowest calibration standard, or there were discrep ancies in meeting certain analyte-specific quality-control criteria. Table 7. Summary statistics for concentrations of selected metals in sediment samples from potentially contaminated sites, by location identification.—Continued [Location identification from table S2. Moisture content is in percent; concentrations are in milligrams per kilogram except mercury is in micrograms per kilogram. less than; E, estimated value1]
24 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Table 8. Mean concentrations of arsenic and mercury in sediment samples from reference and potentially contaminated sites reported in four different studies. [mg/kg, milligrams per kilogram; µg/kg, micrograms per kilogram; BFR, Belle Fourche River; WWC, Whitewood Creek; --, not available; CR, Cheyenne River; CBFRS, Cheyenne and Belle Fourche River sediment study] Study Reference site Potentially contaminated site Surface / subsurface Arsenic (mg/kg) Mercury (µg/kg) Reference Potentially contaminated Reference Potentially contaminated Goddard (1989) BFR upstream from WWC WWC Surface and subsurface 1,600 Goddard (1989) BFR upstream from WWC BFR downstream from WWC Surface and subsurface Goddard (1989) CR upstream from BFR CR downstream from BFR Surface and subsurface U.S. Environmental Protection Agency (2005) Moreau River CR downstream from BFR Surface 1,270 1,280 U.S. Environmental Protection Agency (2005) Moreau River Arm of Lake Oahe Cheyenne River arm of Lake Oahe Surface 1,290 1,260 EngineeringEnvironmental Management, Inc. (2004) Terraces above Lake Oahe CR valley bottom upstream from Lake Oahe Surface EngineeringEnvironmental Management, Inc. (2004) Terraces above Lake Oahe CR valley bottom upstream from Lake Oahe Subsurface CBFRS (2009–10) High terraces and CR upstream from BFR BFR downstream from WWC Surface 1,316 CBFRS (2009–10) High terraces and CR upstream from BFR BFR downstream from WWC Subsurface 1,316 CBFRS (2009–10) High terraces and CR upstream from BFR CR downstream from BFR Surface 1,316 1Concentrations less than detection levels were evaluated as one-half the detection level. 2Mean concentration was less than the lowest detection level (90 µg/kg). Greater than one-half of all samples had concentrations less than the detection level. 3Mean concentration for all reference samples combined.
Concentrations of Selected Metals in Sediment 25 Land surface Surface arsenic Subsurface arsenic Maximum reference concentration EXPLANATION Arsenic concentration, in milligrams per kilogram 1,000 10,000 1,000 10,000 1,000 10,000 1,000 10,000 Land-surface elevation, in meters, above North American Vertical Datum of 1988 BF1 BF2 BF3 Distance from initial point along transect, in meters BF4 Figure 6. Cross-sectional profiles of land-surface elevations and arsenic concentrations in surface and subsurface sediment samples from transects on the middle Belle Fourche River.
26 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Figure 7. Cross-sectional profiles of land-surface elevations and arsenic concentrations in surface sediment samples from transects on the lower Cheyenne River. 1,000 Arsenic concentration, in milligrams per kilogram Land-surface elevation, in meters, above North American Vertical Datum of 1988 1,000 1,200 1,600 Distance from initial point along transect, in meters 2,000 2,400 1,000 1,000 1,200 1,400 CR1 CR3 1,000 1,200 1,400 CR2 Land surface Surface arsenic Maximum reference concentration EXPLANATION
Concentrations of Selected Metals in Sediment 27 Figure 8. Cross-sectional profiles of land-surface elevations and mercury concentrations in surface and subsurface sediment samples from transects on the middle Belle Fourche River. Land surface Surface mercury Subsurface mercury Maximum reference concentration EXPLANATION Mercury concentration, in micrograms per kilogram 1,000 10,000 1,000 10,000 1,000 10,000 1,000 10,000 Land-surface elevation, in meters, above North American Vertical Datum of 1988 BF1 BF2 BF3 Distance from initial point along transect, in meters BF4
28 Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers Figure 9. Cross-sectional profiles of land-surface elevations and mercury concentrations in surface sediment samples from transects on the lower Cheyenne River. 1,000 Mercury concentration, in micrograms per kilogram Land-surface elevation, in meters, above North American Vertical Datum of 1988 1,000 1,200 1,600 Distance from initial point along transect, in meters 2,000 2,400 1,000 1,000 1,200 1,400 CR1 CR3 1,000 1,200 1,400 CR2 Land surface Surface mercury Maximum reference concentration EXPLANATION
References Cited 29 References Cited American Society for Testing and Materials, 2011, Standard D2216—Standard test methods for laboratory determina tion of water (moisture) content of soil and rock by mass: West Conshohocken, Penn., ASTM International, accessed September 28, 2011, at ://www.astm.org/Standards/ D2216.htm. Bergeland, M.E., Ruth, G.R., Stack, R.L., and Emerick, R.J., 1976, Arsenic toxicosis in cattle associated with soil and water contamination from mining operations: South Dakota State University, Agricultural Experiment Station Journal, no. 1461, p. 311–316. Caddey, S.W., Bachman, R.L., Campbell, T.J, Reid, R.R., and Otto, R.P., 1991, The Homestake Gold Mine, an Early Proterozoic iron-formation-hosted gold deposit, Lawrence County, South Dakota: U.S. Geological Survey Bulletin 1857, chap. J, 67 p. Duller, G.A.T., 2008, Luminescence dating—Guidelines on using luminescence dating in archaeology: Swindon, United Kingdom, English Heritage, 44 p. Engineering-Environmental Management, Inc., 2004, Eleva tion 1620 sediment study—Cheyenne River arm, Lake Oahe, South Dakota: Littleton, Colo., Engineering-Environ mental Management, Inc., 54 p. plus appendixes. Geoprobe Systems, 2012, 54TR, accessed June 13, 2012, at ://geoprobe.com/54tr. Goddard, K.E., 1989, Composition, distribution, and hydro logic effects of contaminated sediments resulting from the discharge of gold milling wastes to Whitewood Creek at Lead and Deadwood, South Dakota: U.S. Geological Sur vey Water-Resources Investigations Report 87–4051, 76 p. Marron, D.C., 1992, Floodplain storage of mine tailings in the Belle Fourche River system—A sediment budget approach: Earth Surface Processes and Landforms, v. 17, p. 675–685. Mitchell, S.T., 2009, Nuggets to neutrinos—The Homestake story: LaVergne, Tenn., Steven T. Mitchell, 738 p. Redden, J.A., and DeWitt, Ed, 2008, Maps showing geology, structure, and geophysics of the central Black Hills, South Dakota: U.S. Geological Survey Scientific Investigations Map 2777, 44 p. pamphlet, 2 sheets. U.S. Environmental Protection Agency, 1971, Pollution affect ing water quality of the Cheyenne River system western South Dakota: Denver, Colo., Division of Field Investiga tions, 89 p. plus map. U.S. Environmental Protection Agency, 1973, Mercury, zinc, copper, arsenic, selenium, and cyanide content of selected waters and sediment along Whitewood Creek, the Belle Fourche River, and the Cheyenne River in western South Dakota: EPA Report No. SA/TSB-17, 31 p. plus appendixes and map. U.S. Environmental Protection Agency, 2005, Ecological risk assessment for the Cheyenne River, South Dakota: Denver, Colo., 27 p. U.S. Environmental Protection Agency, 2006, Human health risk assessment for the Cheyenne River, South Dakota: Denver, Colo., U.S. Environmental Protection Agency Region VIII, 25 p. U.S. Environmental Protection Agency, 2011a, Superfund Program—Whitewood Creek, accessed February 10, 2012, at ://www.epa.gov/region8/superfund/sd/whitewood/ index.. U.S. Environmental Protection Agency, 2011b, Test methods for evaluating solid waste, physical/chemical methods, accessed September 28, 2011, at ://www.epa.gov/ epawaste/hazard/testmethods/sw846/index.htm. U.S. Government, 2000, Public Law 106–541, Water Resources Development Act of 2000, 106th Congress, accessed June 13, 2012, at ://www.gpo.gov/fdsys/pkg/ PLAW-106publ541//PLAW-106publ541.htm.
Supplemental Data Tables This supplemental section contains links to data tables that present the analytical results of selected metal concentrations in sediment samples from reference sites (table S1) and poten tially contaminated sites (table S2). The Microsoft Excel spreadsheet (Table_S1.xls) contains a worksheet (worksheet: Intro) that describes the documentation and abbreviations used in table S1. The Microsoft Excel spreadsheet (Table_S2.xls) contains a worksheet (worksheet: Intro) that describes the documentation and abbreviations used in table S2.
Publishing support provided by the: Rolla and Denver Publishing Service Centers For more information concerning this publication, contact: Director, USGS South Dakota Water Science Center 1608 Mt. View Road, Rapid City, SD 57702 (605) 394-3200 Or visit the South Dakota Water Science Center Web site at: ://sd.water.usgs.gov/
Stamm and Hoogestraat—Concentrations of Selected Metals in Fluvial Deposits along the Lower Cheyenne and Middle Belle Fourche Rivers—Data Series 695