Lead in Soil by Field Portable X-Ray Fluorescence Spectrometry—An Examination of Paired In-Situ and Laboratory ICP-AES Results
David A. Binstock, Ph.D., RTI International, Research Triangle Park, NC

Soil-Lead Partitioning in Southern and Northern Hemisphere: A Comparative Evaluation
Carol J. Miller, Wayne State University, Detroit, MI

In-Situ Stabilization of Metals Contaminated Soils Using Phosphate Based Admixture 
Gary M. Garfield, URS Corporation, Salem, NY

In-situ Remediation of Chromium with Nanoiron
David Henderson, New Jersey Department of Environmental Protection, Hamilton, NJ

Boston Mine: Cleanup of Mercury at an Abandoned Placer Gold Mine
Gregory J. Reller, Tetra Tech EM, Inc., Rancho Cordova, CA

Restoring Silver Bow Creek in the Upper Clark Fork River Basin in Western Montana 
Gregory J. Mullen, Montana Natural Resource Damage Program, Helena, Montana

Lead in Soil by Field Portable X-Ray Fluorescence Spectrometry—An Examination of Paired In-Situ and Laboratory ICP-AES Results

David A. Binstock, Ph.D., RTI International, P.O. Box 12194 , Research Triangle Park , NC 27709 , Tel: 919-541-6896, Email: Binnie@rti.org
William F. Gutknecht, Ph.D., RTI International, P.O. Box 12194, Research Triangle Park, NC 27709, 919-541-6883, Email: wfg@rti.irg
Andrea C. McWilliams, RTI International, P.O. Box 12194 , Research Triangle Park , NC 27709 , Tel: 919-485-5520, Email: acm@rti.org

RTI has conducted a study to compare the performance of field-portable X-ray fluorescence (FPXRF) with lab-based ICP-AES. The study was designed to produce paired ICP-FPXRF measurements from soil samples collected at multiple locations within each of nine geographically remote study sites. Soil samples tested in the field by FPXRF were returned to the laboratory for confirmatory lead analysis by ICP-AES. Evaluation of study data revealed the following: ICP-AES soil lead measurements were systematically higher than the paired FPXRF measurements and the degree of correspondence between ICP-AES and FPXRF measurements on the same soil sample is a function of a variety of factors, including soil moisture and particle size, specific to a particular location or site.  In order to minimize the differences between field and laboratory results, RTI has developed a new protocol for field-drying and sieving of collected samples and measurement by FPXRF. In order to evaluate this protocol, composite samples were collected following both HUD Guideline and ASTM protocols, measured following drying by FPXRF, and returned to the laboratory for confirmatory ICP-AES analysis. Evaluation of study data from several diverse sites revealed no statistical difference between paired FPXRF and ICP measurements following the new method. A simple, cost-effective in-situ soil lead measurement is now available.

Soil-Lead Partitioning in Southern and Northern Hemisphere: A Comparative Evaluation

Maria Marin, Doctoral Student, Wayne State University, Detroit MI, Email: aq6202@wayne.edu  
Carol J. Miller, Professor, Department of Civil and Environmental Engineering, 2158 Engineering Building, 5050 Anthony Wayne Drive, Wayne State University, Detroit, MI 48202, Tel:  313-577-3876, Email: cmiller@eng.wayne.edu 

An investigation was completed to determine soil-lead content and chemical partitioning of lead in soil samples from two different climatic zones (Maracaibo, Venezuela and Detroit, Michigan, USA).  Various studies have demonstrated the great incidence of soil-lead contamination in metropolitan areas with a high traffic density. The Detroit Metropolitan area exhibits the same trend, having elevated soil-lead concentrations in the central part of the city, with levels decreasing with increasing distance from the inner-city area.  There are no records of soil-lead contamination or lead poisoning prevalence in Maracaibo, Venezuela, but a study performed in Valencia, Venezuela found elevated blood lead levels in children, most of them above the threshold value of 10 μg/dL.  The median of blood lead levels in children in this study was 11.6±5.5 μg/dL.  Elevated blood lead levels have been found throughout Detroit.

The present investigation involved the collection of surficial soil samples, soil characterization, and analytical determination of soil-lead content in these two metropolitan areas. In addition, other tasks included the sequential extraction analysis of soil samples, to determine the chemical partitioning of Pb in different phases of soil.  An additional step is added to the sequential extraction procedure to further break down the organic phase into humic and fulvic acids.  A chelating agent (NTA) is added in each step of the sequential extraction procedure, to prevent readsorption of Pb into the soil, an issue that has been documented extensively.

There are several important differences between Maracaibo and Detroit that may impact the observed soil-lead partitioning.  Certainly, the two cities are located in very different climatic zones.  Venezuela is a tropical country and is very close to the equator, so there is no snow in Maracaibo and, therefore, no road salt application.  It has been suggested that road salt can mobilize Pb through soil through complexation reactions.  Another difference between the two cities is the amount of precipitation, the average annual precipitation in Maracaibo is 57.7 cm, and the average annual precipitation in Detroit is 80 cm of rain and 115 cm of snow.      

Regarding the sources of Pb, in Venezuela leaded gasoline and leaded paint are still in use, so contamination of the soil with Pb has continued for almost 20 years after leaded gasoline was banned in the US.

In-Situ Stabilization of Metals Contaminated Soils Using Phosphate Based Admixture

Rick Greiner, Conoco Phillips Company, TN 5052, 600 N. Dairy Ashford, Houston, TX 77079-1175, Tel: 832-379-6452
Gary M. Garfield, PE, LSP, URS Corporation, 5 Industrial Way , Salem , NH 03079 , Tel: 603-893-0616, Fax: 603-893-6240, Michael Stiller, P.E., LSP, URS Corporation, 260 Franklin Street, Suite 300, Boston, MA 02110, Tel: 617-542-4244   
Russ Wilder, LSP, PG, URS Corporation, 5 Industrial Way , Salem , NH 03079 , Tel: 603-893-0616, Fax: 603-893-6240

Historic operations of a former fertilizer manufacturing company have resulted in heavy metals contamination in surficial soils above the Massachusetts Contingency plan Upper Concentration Levels (UCLs).  From 1860 to the 1960s, The American Agricultural Chemical Company manufactured phosphate type fertilizers at their Weymouth Neck, Massachusetts facility.  The site is situated on the Weymouth Neck peninsula.  Since the 1960s residential development consisting of high rise condominiums has occurred in and around the 25 acre site.

The results of initial site characterization conducted on a 2.5 acre portion of the site indicated that approximately 90,000 tons of soil had been impacted.  Concentrations of arsenic and lead were present in surficial soils at concentrations up to 5,000 mg/kg and 12,000 mg/kg respectively.  An evaluation of remedial response actions indicated that due to the high population density, the shallow water table (~7 feet), and the volume of soil requiring remediation in-situ soil stabilization was the most feasible remedial alternative.

Bench scale testing indicated that the most effective stabilization admixtures were phosphate based stabilization agents.  Bench scale testing was completed on soils obtained from the site in July 2005.  In October 2005, pilot scale testing was conducted and included the in-situ stabilization of six cells using three different chemical providers.  Soils were stabilized above and below the water table using a rotary head mixer.  Treated soils were sampled for TCLP metals, SPLP metals, pH phosphate, sulfate, and sulfide immediately after stabilization, after 21 days and after 4 months.  In addition, selected samples were analyzed using a multiple SPLP methodology.  The results of the pilot scale testing indicated that the impacted soils could be stabilized and that leaching of the soil would not result in a significant risk to human health and the environment.

Nearly 3,000 tons of admixtures were used to stabilize approximately 90,000 tons of soil.  Soil stabilization was conducted in 40 by 15 foot cells between September and December 2006.  Approximately 250 cells were stabilized from the ground surface to six feet (Upper Lift) and from six feet to twelve to thirteen feet (Lower Lift).  Results of analytical analyses conducted on treated soils indicated that only 5 of the 250 cells required retreatment.  TCLP and SPLP testing indicated successful treatment of the metals impacted soil was achieved within 4 days. The work was conducted in close proximity to condominium residents and adjacent to a salt marsh.

In-situ Remediation of Chromium with Nanoiron

David Henderson, New Jersey Department of Environmental Protection
Harch S. Gill, Ph.D., PARS Environmental, Inc., 6A South Gold Drive , Robbinsville , NJ 08691 , Tel: 609-890-7277, Fax: 609-890-9116, Email hgill@parsenviro.com

From 1905 to 1971, three major facilities in New Jersey were involved in the extraction of chromium from mineral chromite. In this period, over 2,000,000 tons of chromite ore processing residue (COPR) was produced. This waste product was used by the construction industry for various purposes such as grading material for roadways and as fill material in residential, industrial and commercial construction. The New Jersey Department of Environmental Protection (NJDEP) has classified over 150 sites in Hudson County as chromium-contaminated areas. These sites have chromium concentrations ranging from a few parts per million (mg/kg) to over 5 percent by weight.

The remediation of chromium-contaminates sites presents a technological and economic challenge; none of the currently available treatment methods have been effective and/or cost-effective. Recent research and development has demonstrated that hexavalent chromium can be rapidly reduced and immobilized at the surface of nanoscale zero-valent iron particles. Characterizations with High-Resolution X-ray Photoelectron Spectroscopy (HR-XPS) indicates that Cr(VI) is rapidly reduced to Cr(III), which is subsequently incorporated into the iron oxide shell of the nanoiron and forms an alloy-like Cr-Fe hydroxide which is stable and serves as a sink for Cr(VI). Due to the fast reaction kinetics and high chromium removal capacity, nanoiron is an effective reagent for in-situ immobilization of chromium contaminated soil and groundwater.

In the Fall of 2006, the NJDEP funded a comprehensive technology demonstration project in Jersey City in Hudson County to evaluate the in-situ remediation of chromium-contaminated soils and groundwater using zerovalent nanoiron. Tests were done in both the saturated zone as well as the vadoze zone. This paper presents the results of the comprehensive demonstration project and discusses the methodology for injecting the nanoiron to achieve optimum results.

Boston Mine: Cleanup of Mercury at an Abandoned Placer Gold Mine

David Lawler, US Department of the Interior Bureau of Land Management, 2800 Cottage Way, Suite W-1834, Sacramento, CA 95825-1886, Tel: 916-978-4365, Email: David_Lawler@ca.blm.gov
Joel Bauman, Tetra Tech EM, Inc., 10860 Gold Center Drive, Suite 200 , Rancho Cordova , CA 95670 , Tel: 916-853-4538, Email: joel.bauman@ttemi.com
Gregory J. Reller, Tetra Tech EM, Inc., 10860 Gold Center Drive, Suite 200 , Rancho Cordova , CA 95670 , Tel: 916-853-4531, Email: greg.reller@ttemi.com

Elemental mercury was widely used at hundreds of placer mines in the Western Sierra Nevada to recover fine gold.  Estimated losses of mercury to the environment during historical gold mining range from 10 to 30 percent.  Much of this elemental mercury remains within the western Sierra watersheds.  Regional studies of watersheds on the west slope of the Sierra Nevada Mountains in California have identified elevated levels of mercury in water, sediment and biota.  In response to these observations, fish consumption advisories were issued by public health organizations.   Agencies that administer public lands, including the BLM, are responsible for the control and cleanup of mercury from legacy mines under their jurisdiction.  Regional sampling identified the drain tunnel outlet at the Boston Mine as a site of significant bioaccumulation in comparison to other placer mines that were sampled.  Site specific investigations identified up to 45 grams of mercury per kilogram of sediment at the site.  In addition, mercury in water from the drain tunnel outlet exceeded water quality standards.  BLM determined that the drain tunnel at the Boston Mine represented an ideal opportunity to evaluate removal of mercury from sediment at these legacy mines.  Successful implementation of on-site sediment processing resulted in cleanup of the drain tunnel and recovery of 1,162 grams of elemental mercury, 264 grams of amalgam, and lead and gold from site sediment.  Washed sediment was suitable for burial on site without additional stabilization; heavy mineral concentrates were stabilized with cement prior to burial on site.  The recovered mercury was recycled.  Post removal monitoring is ongoing.   

Restoring Silver Bow Creek in the Upper Clark Fork River Basin in Western Montana   

Gregory J. Mullen, Environmental Science Specialist, Montana Natural Resource Damage Program, 1301 East Lockey,  Helena, Montana,  59620-1425, Tel:  406-444-0228, Fax:  406-444-0236

Decades of mining and mineral processing operation in and around Butte and Anaconda released substantial quantities of hazardous substances into the Upper Clark Fork River Basin between Butte and Milltown in western Montana , which now is the largest Superfund complex in the U.S.   These hazardous substances extensively injured the area’s natural resources including Silver Bow Creek, which extends from Butte approximately 23 miles to the Warm Springs Ponds, a four square mile water treatment facility located near the headwater of the Clark Fork River .  Since the late 1880’s, toxic discharges produced a metals-impacted floodplain and streambed and virtually eliminated aquatic life in Silver Bow Creek.

Using part of a $215 million partial settlement in 1999 with Atlantic Richfield Company, the State of Montana ’s Department of Environmental Quality (DEQ) and Natural Resource Damage Program , through a grant to the local Greenway Service District, are conducting an integrated remediation and restoration, respectively, of Silver Bow Creek.  Since work began in 1999, three million cubic yards of tailings have been removed, 10 miles of stream reconstructed, and 850 acres of floodplain have been restored to productive wildlife habitat. Together these agencies are expediting and economizing by using the same contractors and contracts for the remediation and restoration effort, which is most likely the largest such integrated effort in the country.  Recent monitoring of the State’s injured resources along Silver Bow Creek has shown dramatic improvements to water quality, streamside soils and wildlife habitat. The state is over half done with this estimated $80 million integrated remedy/restoration effort, which is expected to be complete by 2011.  The Greenway Service District is acquiring public ownership and developing a recreational greenway trail corridor along the restored creek corridor.

Top