Dissolution Kinetics of Metallic Tungsten In The Presence of Common Alloying Elements
Adebayo Ogundipe, Stevens Institute of Technology, Hoboken, NJ  

Pragmatic Approach to Remediation of Mercury in Wastewater:  Source Characterization, Implementation and Results
Barbara L. Oslund, Solutions Industrial & Environmental Services, Inc., Raleigh, NC  

Comparative Analysis of Sorptive Capacities of Toledo Soils for Heavy Metal Remediation
Catherine L. Buchanan, University of Toledo, Toledo, OH

Influence of Aging in Soil on the Dermal Penetration of Hexavalent and Trivalent Chromium
Mohamed S. Abdel-Rahman, New Jersey Medical School,  Newark, NJ

Predicting Mercury Cycling and Methylation in NY/NJ Harbor
Robert Santore, HydroQual, Inc., Camillus, NY

Trace Metal Distributions in Connecticut Soils

Robert A. Stewart, Ph.D., Consulting Environmental Engineers, Inc., 100 Shield Street, West Hartford, CT 06110-1920, Tel: 860-953-0023; Email: rstewart@cee.net

Improvements to state and federal highways, airports, harbors, and railroads in Connecticut are commonly preceded by environmental investigations to determine whether excavation and dewatering activities will generate regulated wastes.  As part of the investigations, soils in the construction corridors are routinely tested for waste characterization parameters including PCBs, VOCs, PAHs, ETPH, RCRA metals by mass analysis, RCRA metals by SPLP and TCLP, ignitability, corrosivity, and reactivity.  The organic parameters almost exclusively reflect anthropogenic pollutants.  The RCRA metals, and occasionally sulfide, represent natural background levels as well as various sources of pollution.

The focus of this investigation is the distribution of trace metals in native and anthropogenic (disturbed) soils.  Native soils are primarily Entisols and Inceptisols that developed on glacial till, glaciofluvial and glaciolacustrine deposits, eolian sediments, alluvium, and organic deposits.  Anthropogenic soils, mainly Entisols, formed on a variety of parent materials including hydraulic fill pumped from offshore sandbars, soil manufactured with reclaimed bituminous pavement, estuarine silts, combustion by-products (coal ash, cinders and slag, casting sand), and the aforementioned native soils when used as borrow materials along transportation corridors and in rights-of-way for public utilities. 

The total population of samples is separable into groups that (1) approximate natural background levels of metals, and (2) reflect anthropogenic pollutants to a greater or lesser degree.  Natural background is represented by samples removed from intensive pollutant inputs, such as along rural highways and with increasing depth below grade.  Metal concentrations are elevated as a function of proximity to source, as with shallow soils along major highways, and in response to parent material that may also be an industrial waste.  Certain metals, for instance arsenic, may achieve natural background levels exceeding state remediation standards.

Dissolution Kinetics of Metallic Tungsten in the Presence of Common Alloying Elements

Adebayo Ogundipe, Center for Environmental Systems, Stevens Institute of Technology Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5329, Fax: 201-216-8303, Email: aogundip@stevens.edu
Washington Braida, PhD Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5681, Fax: 201-216-8303, Email: wbraida@stevens.edu
Christos Christodoulatos, PhD Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5675, Fax: 201-216-8303, Email: christod@stevens.edu
Dimitris Dermatas, PhD Stevens Institute of Technology, Civil, Environmental, and Ocean Engineering Department, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-8926, Fax: 201-216-5352, Email: ddermata@stevens.edu

To avoid potential environmental insults that could arise from the use of tungsten made materials in general and new tungsten-based munitions, it is necessary to fully understand how these materials will behave after they have been released to the environment.  Previous research reports that tungsten dissolves in large quantities reaching up to 500 mg/L in aqueous solutions. The amount of tungsten dissolved appears to be dependent on the alloying elements. This research aims at further understanding the processes involved in the leaching of metallic tungsten once released into the environment by studying the dissolution kinetics of tungsten powder alone and in the presence of other metallic powders (90:10 binary mixtures with Co, Cu, Ni, and Fe). The initial conditions for the dissolution reactors were; pH between 6.9 and 7.2, ORP between 260 and 290 mv, dissolved oxygen between 6.6 and 7.8 mg/L. The variations of pH, ORP, dissolved oxygen and dissolved metal concentration were followed over a 46 days period. A reduction in pH was measured in all the reactors but very substantial (>4 pH units) for the W:Cu mixture.  The magnitude of pH reduction was in the order: W:Cu >W (Sigma Aldrich) >W (munitions grade) >W:Fe >W:Ni >W:Co.  Reductions in dissolved oxygen occurred in all the reactors with very large reductions recorded for the W:Cu and W:Fe mixtures (82 and 95%, respectively).  The ORP behavior was more erratic, a large reduction in ORP was measured for the W:Fe mixture while for munitions grade W, W:Ni and W:Co mixtures the value was fairly constant.  Increased ORP values were observed in the reactors containing W from Sigma Aldrich and W:Cu mixture. Modeling of the dissolution kinetics and speciation changes over the period of study was performed using the Visual Minteq (version 2.31) software. The information gathered sheds some light on the dissolution behavior of tungsten alloys in the environment.

Pragmatic Approach to Remediation of Mercury in Wastewater:  Source Characterization, Implementation and Results

Barbara L. Oslund, P.E., Solutions Industrial & Environmental Services, Inc., 3722 Benson Drive, Raleigh, NC 27609, Tel: 919- 873-1060, Fax: 919- 873-1074, Email: boslund@solutions-ies.com
Dr. Robert C. Borden, P.E., Solutions Industrial & Environmental Services, Inc., 3722 Benson Drive, Raleigh, NC 27609, Tel: 919- 873-1060, Fax: 919- 873-1074, Email: rcborden@solutions-ies.com
Christie Zawtocki, P.E., Solutions Industrial & Environmental Services, Inc., 3722 Benson Drive, Raleigh, NC 27609, Tel: 919- 873-1060, Fax: 919- 873-1074, Email: rcborden@solutions-ies.com

Beginning in 2003, a large pharmaceutical research and development company was experiencing dissolved mercury in their wastewater, often exceeding concentrations allowed by their Industrial Discharge Permit with the local POTW.  Previous sewer cleaning efforts resulted in limited improvement. However, in the intervening time, more stringent analytical methods were adopted and lower discharge limits increased the potential for repeat non-compliance in their discharge. The company retained Solutions-IES to implement intensive source characterization activities to identify the problem and develop a remediation plan.

Monitoring data from sewage discharge outfalls identified general campus areas that were contributing to the elevated mercury.  The source characterization activities indicated that fumehood, laboratory, and utility closet sink traps contained significant mercury concentrations, as did selected laboratory and sanitary waste manholes and the campus Energy Center.  The first remediation phase focused on removing trapped mercury from the interior facility infrastructure upstream of the impacted outfalls. Review of engineering drawings indicated three sink trap types and a complex laboratory and sanitary waste handling infrastructure.  Different cleaning procedures were tested on each type of sink before full-scale implementation.  Solutions-IES then oversaw cleaning and testing of 292 laboratory and fumehood sink traps, 28 utility closet sink traps, selected exterior laboratory and sanitary waste manholes, and floor drains.  Dissolved mercury concentrations were reduced by 12% to 98% when comparing post-cleanup to baseline samples.

The second remediation phase involved cleaning accumulated biomass and scale from over 3,000 feet of exterior laboratory and sanitary waste collection systems upstream of the impacted outfalls, using pipe location and cleaning techniques similar to those used to locate, clean and evaluate municipal collection systems.  Over 13,000 gallons of water and solids were removed from the system, containing approximately 3.5 grams of mercury.  Although a seemingly small amount, its removal resulted in system-wide reduction by up to 99% with measured concentrations now generally below the permit discharge limits.

Comparative Analysis of Sorptive Capacities of Toledo Soils for Heavy Metal Remediation

Catherine L. Buchanan, University of Toledo, Department of Earth, Environmental and Ecological Sciences, Mail Stop 604, 2801 Bancroft Ave, Toledo, Ohio, 43606, Tel: 419-699-9968, Fax: 419-530-4421, Email: cbuchan3@utnet.utoledo.edu
Dr. Alison Spongberg, University of Toledo, Department of Earth, Environmental and Ecological Sciences, Mail Stop 604, 2801 Bancroft Ave, Toledo, Ohio, 43606, Tel: 419-530-4091, Fax: 419-530-4421, Email: aspongb@utnet.utoledo.edu

In-situ treatment for remediation of pollutants is a technologically expanding field because of the wide range of pollutants that now exist in the ecosystem and lack of a solution capable of removing every type of pollutant.  Heavy metals are persistent in the ecosystem due to anthropogenic impacts.  The use of soils for remediation of heavy metal contamination is becoming more popular because of ease of implementation and cost effectiveness.  The ideal soils to use would be local soils within proximity to the project to minimize transport costs.  The soils chosen for this study have a range and variability of heavy metal sorption capacities.  The soils were taken from known polluted sites and from sites where the soils are being proposed for heavy metal containment.  The results of the study may influence which soil is to be used for the remediation of heavy metal contamination.

Influence of Aging in Soil on the Dermal Penetration of Hexavalent and Trivalent Chromium

Mohamed S. Abdel-Rahman, Ph.D., Pharmacology and Physiology Dept., UMDNJ, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, 07101, Tel: 973-972-6568, Fax: 973-972-4554, Email: abdelrms@umdnj.edu
Gloria A. Skowronski, Ph.D., Pharmacology and Physiology Dept., UMDNJ, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, 07101, Tel: 973-972-6690, Fax: 973-972-4554, Email: skowroga@umdnj.edu
Rita M. Turkall, Ph.D., Pharmacology and Physiology Dept., UMDNJ, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, 07101, Tel: 973-972-5096, Fax: 973-972-4554, and Clinical Laboratory Sciences Dept., UMDNJ, School of Health Related Professions, 65 Bergen Street, Newark, NJ, 07107, Tel: 973-972-5577, Fax: 973-972- 8527, E-mail: turkalrm@umdnj.edu

Soil and groundwater are contaminated with chromium in thousands of sites in the United States and in the developed world. Although direct dermal contact with high concentrations of chromium, especially Cr (VI) compounds, can produce skin burns, blisters, and skin ulcers, sensitive individuals may develop rashes and erythema from contact with chromium in soil.  Health risk assessments often do not consider the amount of soil-sorbed metal that is absorbed by the body but rely on the total concentration of metal in soil that can be extracted by rigorous procedures. This practice can overestimate health risks and soil remediation goals because metals can be sequestered in soil with time (“aging”) thereby decreasing bioavailability. The influence of aging on the dermal penetration of Cr (III) as chromic chloride or Cr (VI) as sodium chromate was evaluated in two soils – Atsion (a sand) and Keyport (a sandy clay loam). Dermal penetration was measured in vitro through dermatomed pig skin by Teflon flow-through diffusion cell methodology. After four months in soil, the dermal penetration of both species was decreased by 91 - 97% relative to pure chromium (without soil). Furthermore, the dermal penetrations of Cr (III) and Cr (IV) were reduced more by aging in the Atsion soil (83% and 68%, respectively) than in the Keyport soil (40% and 57%, respectively) relative to chromium in freshly treated soils. The data suggest that an increase in environmentally acceptable endpoints for chromium will be dependent on soil type and time in soil. (Supported through funding from the Hazardous Substance Management Research Center and the New Jersey Commission on Science and Technology).

Predicting Mercury Cycling and Methylation in NY/NJ Harbor

Robert Santore, HydroQual, Inc., 4914 West Genesee St., Camillus, NY 13031, Tel: 315-484-6220, Fax: 315-484-6221, Email: rsantore@hydroqual.com
Aaron Redman, HydroQual, Inc., 4914 West Genesee St., Camillus, NY 13031, Tel: 315-484-6220, Fax: 315-484-6221
James Wands, HydroQual, Inc., 1200 MacArthur Avenue, Mahwah, NJ 07430, Tel: 201-529-5151, Fax: 201-529-5728
Subir Saha, HydroQual, Inc., 1200 MacArthur Avenue, Mahwah, NJ 07430, Tel: 201-529-5151, Fax: 201-529-5728
Robin Miller, HydroQual, Inc., 1200 MacArthur Avenue, Mahwah, NJ 07430, Tel: 201-529-5151, Fax: 201-529-5728
Kevin Farley, HydroQual, Inc., 1200 MacArthur Avenue, Mahwah, NJ 07430, Tel: 201-529-5151, Fax: 201-529-5728
Dominic Di Toro, HydroQual, Inc., 1200 MacArthur Avenue, Mahwah, NJ 07430, Tel: 201-529-5151, Fax: 201-529-5728

The NY and NJ harbor has been impacted by historical discharges of mercury, and continues to receive mercury inputs from a combination of sources including combined sewer overflows, treatment plant discharges, stormwater runoff, river discharges, and atmospheric inputs.  We have developed a mercury cycling model as part of a larger effort to simulate the fate and transport of contaminants including mercury in the New York and New Jersey harbor and nearby water bodies in part to evaluate how natural attenuation and remedial management of the area may affect fish tissue mercury concentrations in the future.  Understanding and predicting mercury impacts on aquatic organisms is particularly challenging, due to the complex transformations that mercury can undergo in water and sediments including the formation of methylmercury.  Methylmercury is much more toxic and much more likely to bioaccumulate than other forms of mercury, and its formation is dependent on a number of environmental factors including the availability of mercury, and suitable conditions in aquatic sediments where methylation largely occurs.  Our modeling approach is based on the considerable information in the scientific literature linking mercury methylation to the activity of sulfate reducing bacteria.  Our model also includes the simulation of processes related to carbon diagenesis, including sulfate reduction, in order to predict sediment interactions and oxygen demand on the quality of the water column.  These simulated sulfate reduction rates were also used as one of the key factors responsible for determining methylation rates.  The advantage of this approach is that methylation rates are predicted in a mechanistic framework, and are not used as a calibration parameter to fit observed methylmercury concentrations.   This approach allows direct linkages between mercury methylation and other water quality factors, and can provide explanations for season patterns in methylation rates, and for differences in rates observed in different water bodies. 

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