Sponsored by ARCADIS U.S., Inc. and International Tungsten Industry Association (ITIA)

Tungsten Distribution at Camp Edwards Small Arm Ranges
Jay L. Clausen, US Army Engineer Research and Development Center, Hanover, NH

Analytical Method Development for Tungsten in Groundwater by SW-846 Method 6020 by ICP/MS (Lessons Learned)
Mark R. Koenig, USACE Project Chemist, Concord, MA

Comparison of XRF to Laboratory Based Methods for Tungsten and Other Metals
Jay Clausen, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanover, NH
Susan Taylor, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanover, NH
Bonnie Packer, US Army Environmental Center, Aberdeen Proving Ground, MD
Kimberely Watts , US Army Environmental Center, Aberdeen Proving Ground, MD

Tungsten Geochemistry: Fate and Transport of Tungsten at Small Arms Ranges
Michael J. Pardus, ARCADIS U.S., Inc., Pittsburgh, PA

Tungsten Fate and Transport as a Function of Iron Redox Cycling and Associated Biotic-Abiotic Reactions   
Kevin T. Finneran, University of Illinois at Urbana/Champaign, Urbana, IL

Subchronic (90-Day) Oral Toxicity of Sodium Tungstate in Rats
W.C. McCain, U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD

Preliminary Assessment of Tungsten Risk-Based Screening Values and Toxicity Benchmarking
John D. Schell, ARCADIS Inc., Houston, TX

Tungsten Distribution at Camp Edwards Small Arms Ranges

Jay Clausen, Susan Taylor, Dennis Lambert, Ronald Bailey, Susan Bigl, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290
Anthony Bednar, Steve Larson, US Army Corps of Engineers, Environmental Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180-2802
Chuck Ramsey, Envirostat Inc., P. O. Box 636, Fort Collins, CO 80522 .
Bonnie Packer, US Army Environmental Center, 5179 Hoadley Road, Aberdeen Proving Ground, MD 21010-5401
Nancy Perron, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290
Kimberly Watts, US Army Environmental Center, 5179 Hoadley Road, Aberdeen Proving Ground, MD 21010-5401

The US Army has an interest in knowing the distribution and concentration of tungsten present in range soils where tungsten/nylon rounds have been used in training with small arms weapon systems.  A study conducted at Camp Edwards, Massachusetts assessed three small arms firing ranges.  Surface soil tungsten levels ranged from 82 to 1,534 milligram per kilogram (mg/kg) in the Berm Face, 29 to 932 mg/kg in the Trough, 1.6 to 147 mg/kg at the Firing Point/Range Floor/Target, and 17 to 113 mg/kg behind the berm face.  The highest observed tungsten concentrations were observed in surface soil samples (0-5 cm) from the bullet pockets on the berm face.  Background surface soil tungsten levels for Camp Edwards are 1.5 mg/kg. Subsurface soil tungsten levels decreased markedly over a 150 centimeter depth interval, although the concentration of tungsten did not reach background levels.

Tension lysimeters were installed at various sampling intervals within the berm face and below the trough to assess pore-water migration of tungsten-laden water.  Pore-water tungsten concentrations varied from < 0.05 to 400 mg/L over four sampling events.  Five of the lysimeters exhibited an increasing tungsten concentration trend, three a decreasing trend, and the remainder of the 24 total exhibited no trend.  Lysimeters installed in background locations indicated ambient tungsten levels of 0.01 to 0.17 mg/L.

A monitoring well completed in the aquifer, approximate depth to water of 36 meters, and tens of meters downgradient of one berm face exhibited fluctuating levels of tungsten.  The first two sampling events indicated tungsten at 15 and 22 micrograms per liter (ug/L).  Tungsten levels increased to 530 ug/L following a period of heavy precipitation. The fourth and fifth sampling event revealed a groundwater concentration of <5 ug/L. Prior to the fourth sampling event soil from the berm face containing greater than 150 mg/kg tungsten was removed.

Analytical Method Development for Tungsten in Groundwater by SW-846 Method 6020 by ICP/MS (Lessons Learned)

Mark R. Koenig, USACE Project Chemist, New England District, 696 Virginia Road, Concord, MA  01742-2751, Tel: 978-318-8312, Fax: 978-318-8614, Email: mark.r.koenig@usace.army.mil
Anthony Bednar, U.S. Army Engineer Research and Development Center, CEERD-EPC, Building 3299, 3909 Halls Ferry Road, Vicksburg, MS 039180, Tel: 601-634-3652, Email: anthony.j.bednar@usace.army.mil
Paul Nixon, Remedial Project Manager, Impact Area Groundwater Study Program, 1803 West Outer Road, Camp Edwards, MA 02542, Tel: 508-968-5620, Email: paul.nixon@us.army.mil
Laurie Ekes, Project Chemist, Environmental Chemical Corporation, PB 519 Otis ANGB, MA  02542, Phone; 508-968-5620, Email, lekes@ecc.net
Paul Nixon, ANGB, BP- 565 West Outer Road , Otis , MA   02542 , Tel: 508-968-5620, Email: nixon@us.army.mil
Michael E. Ketterer, Professor, Department of Chemistry and Biochemistry Northern Arizona University, Box 5698, Flagstaff, AZ  86011-5698, Tel: 928-523-7055, Fax: 928-523-8111, Email: michael.ketterer@nau.edu
Jay L. Clausen, Physical Reasearch Scientist, US Army Engineer Engineer Research and Development Center, Cold Regions Research Engineering Laboratory (CRREL), 72 Lyme Road, Hanover, NH 03755-1290, Tel: 603-646-4597, Fax: 603-646-4785, Email: jay.l.clausen@erdc.usace.army.mil
Nina Duston, Ph.D., Chemist III, Sen. W. X. Wall Experiment Station, Massachusetts Dept. Environmental Protection, 37 Shattuck Street, Lawrence, MA 01843, Tel: 978-682-5237, ext. 377, Email: nina.duston@state.ma.us

The Small Arms Ranges at MMR that have been used for training and several ranges have used the tungsten “Green Bullets”. The oxidation of the powdered tungsten in these “Green Bullets” forming the leachable species, the tungstate anion, has created a potential treat to tungstate contaminating the sole source aquifer located under the Massachusetts Military Reservation, Camp Edwards, in Falmouth, MA. The NGB USACE and ECC were tasked with sampling and analyzing for tungsten in groundwater monitoring wells in and around several of the SAR target and berm areas where the majority of the tungsten bullets were fired and located.

We readily realized that there were not many of our MMR commercial labs performing tungsten analyses, nor did they have experience with tungsten analysis by Method 6020 ICP/MS. We worked closely with the ERDC, Vicksburg , MS Waterways Experiment Station Chemistry section who had developed their own tungsten methods for soil and groundwater. ERDC also had several years of experience with tungsten analysis by ICP/MS, as well as knowledge of its unique chemical properties and analysis performance issues.

NGB, USACE and ECC headed up an analytical method development team using 4 laboratories (STL-VT, ERDC, MADEP and the University of Northern Arizona ) and let them go about their own SW-846 Performance-Based Method Development approach. Since tungsten or the tungstate anion (WO4) is a new emerging contaminant of concern which did not have EPA approved MCL, Risk-based levels/ ground water action levels, sampling/handling, preservation, digestion method, or analysis method approved criteria, there was a great need to develop reliable and robust method specific criteria for tungsten/tungstate analyses at MMR.

The main focus of this presentation will be on the lessoned learned from the different analytical approaches used by the different labs for tungsten analysis by SW-846 Method 6020 ICP/MS. The presentation will cover; analytical performance issues of tungsten/tungstate anions, findings on QA split comparison between labs, discrepancies findings, PE- sample results and matrix effects, speciation of the tungstate anion, and the choices of certified Vender Stock-Calibrations standards. The need for a standardized EPA approved tungsten methodology will be discussed, as well as the need for more toxicity studies and risk assessments; so that we get a better idea of what groundwater concentration levels will be considered toxic to human and ecological species.

Comparison of XRF to Laboratory Based Methods for Tungsten and Other Metals

Jay Clausen, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290, US, Tel: 603-646-4597, Fax: 603-646-4785, Email: Jay.L.Clausen@erdc.usace.army.mil
Susan Taylor, US Army Corps of Engineers, Environmental Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290, US, Tel: 603-646-4239, Fax: 603-646-4785, Email: Susan.Taylor1@erdc.usace.army.mil
Bonnie Packer^, US Army Environmental Center, 5179 Hoadley Road, Aberdeen Proving Ground, MD 21010-5401, US, Tel: 410-436-6848, Fax: 410-436-6836, Email: Bonnie.Packer@us.army.
Kimberely Watts, US Army Environmental Center, 5179 Hoadley Road, Aberdeen Proving Ground, MD 21010-5401, US, Tel: 410-436-6843, Fax: 410-436-6836, Email: Kimberely.Watts@us.army.mil

As part of a study looking at the mobility of tungsten, the distribution and concentration of tungsten as well as other metals in small arms range soils was evaluated on-site using hand-held X-ray fluorescence (XRF) instruments and in a laboratory by inductively coupled plasma (ICP) analysis.  The evaluation consisted of the testing of two different types of XRF units (X-ray tube and radioactive isotopes technologies) along with equipment from the two different manufacturers.  In the field, the XRF instruments were used to confirm our conceptual design, rank decision units for quality assurance applications (field sample replicates), and determine the necessity and depth of profile sampling.  Comparisons between real-time field measurements and laboratory post-processed samples with the XRF will be presented.  Finally, the XRF field results were compared with those obtained utilizing modified versions of the US Environmental Protection Agency (EPA) SW-846 Methods 3050B, 3051, 6010B, and 6020.  Replicate XRF analysis of soil samples and soil standards in the field indicates good agreement between the two different types of XRF instruments as well as the two equipment manufacturers.  Analysis of the data suggests good reproducibility between XRF measurements in the field (wet soil samples) and laboratory ICP analysis following air-drying and digestion of ground soil samples.  The advantage of using a field instrument such as an XRF instrument is the generation of real-time data allowing for decision-making in the field and the maximum utilization of time and resources.  In addition, if the quality of the data with the XRF can be demonstrated to be as accurate as the ICP then it may be possible to reduce sampling and analysis costs.

Tungsten Geochemistry: Fate and Transport of Tungsten at Small Arms Ranges

Michael J. Pardus, ARCADIS Inc., 600 Waterfront Drive, Pittsburgh, PA 15222, Tel: 412-231-6624, Email: michael.pardus@arcadis-us.com

Between October 1999 and February 2006, tungsten/nylon projectiles were used at small arms ranges at Camp Edwards, Massachusetts .  In January 2007 the U.S. Army Corps of Engineers (USACE) released a study of the fate and transport of tungsten at three of the small arms ranges at Camp Edwards.  As anticipated, tungsten was found in the surface soils at concentrations consistent with its use as a small arms projectile.  Information was also provided regarding subsurface soils, soil pore water, and groundwater concentrations of tungsten.  This presentation uses the data presented in the USACE report as a basis for geochemical modeling of tungsten fate and transport in the environment.  The presentation provides an overview of the model protocol and outputs with respect to tungsten mobility at Camp Edwards.  The model results are then compared with conclusions reached in the USACE report.

Tungsten Fate and Transport as a Function of Iron Redox Cycling and Associated Biotic-Abiotic Reactions  

Kevin T. Finneran, PhD, University of Illinois - Urbana Champaign, Dept of Civil and Environmental Engineering, NCEL 205 N. Mathews, Urbana, IL, 61801, Tel: 217-333-1514, Fax: 217-333-6967, Email: finneran@uiuc.edu

Tungsten is an emerging contaminant of concern at several U.S. military installations in subsurface systems.  This study aimed to identify factors influencing tungsten fate and transport.  Tungsten is most often present as tungstate (WO42-) in moderate pH groundwater.  Tungstate binds to Fe(III) (oxy)hydroxides as a function of pH; however, it has not been determined what effects iron redox cycling has on tungstate mobility or whether tungstate itself can be reduced chemically or biologically. 

Our investigation used bicarbonate buffered suspensions of sodium tungstate amended with poorly crystalline Fe(III) hydroxide in the presence and absence of the electron shuttle anthraquinone-2,6-disulfonate (AQDS).  These suspensions were run at pH 7.0 and pH 4.0.  The reduced form of AQDS (AH2QDS) is a strong abiotic reductant and can quickly reduce Fe(III) to Fe(II); it is unknown whether it can directly reduce tungstate.  Tungstate alone or with the oxidized form of the electron shuttle (AQDS) did not vary over the four day incubation.  The reduced form of the shuttle at pH 7.0 did not alter tungstate concentration.  However, when the pH was lowered to 4.0 the tungstate immediately dropped from 2.0mM to 0.4mM and was further depleted to 0.2mM over the four day incubation.  AH2QDS is a more efficient electron donor at low pH, and EH/pH plots suggest that WO42- can become WO2 at pH 4.0.  Tungstate was slowly removed from solution in Fe(III) amended suspensions; from 1.5mM to 0.7mM over four days.  Tungstate dropped immediately from 2.0mM to 0.7mM in Fe(III) + AH2QDS suspensions, which dropped to 0.5mM over the remaining three days with concomitant Fe(III) reduction.

These data suggest that iron redox cycling influences tungstate fate by adsorptive and possibly reductive processes.  The project will continue investigating these chemical transformations, as well as mixed biological-abiotic reactions with Fe(III)-reducing microorganisms in defined and heterogeneous environmental media.

Subchronic (90-Day) Oral Toxicity of Sodium Tungstate in Rats

W.C. McCain, L. Crouse, M.A. Bazar, M. Thompson, A. Hess-Ruth, P. Beall, and M. Quinn,  Directorate of Toxicology, U.S. Army Center for Health Promotion and Preventive Medicine, 5158 Blackhawk Road, Aberdeen Proving Ground, MD 21010
J. Middleton, PM- Maneuver  Ammunition Systems (MAS), Army Research, Development and Engineering Center (ARDEC), Picatinny , NJ

Tungsten metal was used for the manufacture of small caliber ammunition in a tungsten/nylon matrix referred to as the “green bullet”.  A recent study conducted by the Corps of Engineers at Waterways Experimental Station indicated that soluble forms of tungsten could be formed from the tungsten bullets and enter the ground water.  Sodium tungstate dihydrate, a highly soluble form of tungsten, was administered orally to male and female Sprague-Dawley rats by gavage for 90 consecutive days.  This induced a number of statistically significant alterations in weights, hematology and clinical chemistry at 200 mg/kg.  It was concluded that administration of sodium tungstate at 200 mg/kg to male and female Sprague-Dawley rats via oral gavage for 90 consecutive days resulted in pronounced renal changes, specifically renal tubular necrosis.  Based on a careful evaluation of the data, the Lowest Observable Adverse Effect Level (LOAEL) for the subchronic oral toxicity of sodium tungstate in male and female Sprague-Dawley rats is 200 mg/kg. The No Observable Adverse Effect Level (NOAEL) for the subchronic oral toxicity of sodium tungstate in male and female Sprague-Dawley rats is 20 mg/kg.  A second study exploring the dosage range between 10 and 200 mg/kg was recently completed.  Preliminary information is presented.

Preliminary Assessment of Tungsten Risk-Based Screening Values and Toxicity Benchmarking

John D. Schell, Ph.D., ARCADIS Inc., 2929 Briarpark Drive, Houston, TX 77042-3745, Tel:  713-785-1680, Email: john.schell@arcadis-us.com
Salvatore Giolando, Ph.D., ARCADIS Inc., 3699 Symmes Road, Hamilton, OH 45015, Tel: 513-860-8700, Email: sal.giolando@arcadis-us.com
Dianne Green, ARCADIS Inc., 3699 Symmes Road, Hamilton, OH  45015, Tel: 513-860-8700, Email:  dianne.green@arcadis-us.com
Michael J. Pardus, ARCADIS Inc.,600 Waterfront Drive, Pittsburgh, PA 15222, Tel: 412-231-6624, Email: michael.pardus@arcadis-us.com

During a recent investigation into a purported childhood leukemia cancer cluster in the western US, the Centers for Disease Control (CDC) identified a data gap associated with basic toxicological information on tungsten, the naturally occurring metal.  This concern by CDC, along with the use of W in various industries has stimulated a dramatic increase in the amount of information available on this metal.  Investigations into the toxicity of W have been conducted by academic institutions and military research labs.  A review of a number of these recent studies, some of them not yet published in the scientific literature, provide an insight into the relative potency of W, especially when compared to other naturally occurring and industrial use metals.  Because some of these studies have been conducted using standard protocols, the resulting information can form the basis of a “strawman” toxicity factor which can be used to develop preliminary “safe” environmental concentrations. Using methods employed by EPA to derive risk-based screening values (RBSV), such as the Region 9 Preliminary Remedial Goals, the toxicity factor for W translates into concentrations in soil and drinking water that would be without the risk of causing adverse effects.  These RBSV for soil and water are compared to various levels of tungsten reported in the environment.

In order to compare the toxicological database that exists on tungsten to that of other heavy metals, information presented in the Agency for Toxic Substances and Disease Registry’s (ATSDR’s) draft or final toxicological profiles for 8 heavy metals, including arsenic, beryllium, cadmium, chromium, lead, mercury, tungsten, and uranium were reviewed and summarized.  Additionally, several recently published (within the last 5 years) review articles concerning these heavy metals (excepting uranium) were reviewed.  The purpose of this review was to compile, and subsequently compare, the adverse health effects that have been observed in humans or experimental animals following exposure to these metals as noted by the ATSDR or the authors of the various review articles.  Results from this review will be presented.

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