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Lead Leaching From Soils And In Storm Waters At Twelve Military Shooting Ranges, L. K. Isaacs

Journal of Hazardous Substance Research

Soils from impact berms at 12 military shooting ranges were evaluated for lead leaching by particle-size distribution, sequential extractions, storm water analysis, batch studies with amendments of crushed apatite (FB) and triple-super phosphate (TSP), and column leaching studies with amendments of ashed apatite (FBa) and TSP. Soil particle fractions were determined by ASTM D422-63 and by x-ray diffraction; lead leaching was found by EPA’s SPLP and TCLP. Total and dissolved lead in soils and storm waters were determined by ICP-MS. The residual fraction averaged 79.8% of total mass of lead in all soils. There was significant correlation between TCLP results …

Chromium (Vi) Biosorption By Immobilized Biomass Of Bacillus Ceres M116, D. Bera, P. Chattopadhyay, L. Ray

Journal of Hazardous Substance Research

Biosorption is potentially an attractive technology for treatment of wastewater for retaining heavy metals from dilute solutions. This study investigated the feasibility of Bacillus cereus M¹₁₆ immobilized in different carriers as a biosorbent for chromium removal from aqueous solutions in batch mode; optimum conditions were determined. Experimental results showed the bacterial strain immobilized in calcium alginate gel matrix was most effective in removing Cr(VI) ion from solution. The uptake of metal was very fast initially, and equilibrium was attained within 80 mins. The overall biosorption process was best described by the pseudo second-order kinetics. Intraparticle diffusion was not …

Theoretical Analysis Of Concentration Polarization Effect On Voc Removal By Pervaporation, S. X. Liu, L. M. Vane, M. Peng

Journal of Hazardous Substance Research

Pervaporation is an innovative membrane-based separation technology for volatile organic compound (VOC) removal from contaminated groundwater. Concentration polarization is a process phenomenon occurring in pervaporation and several other membrane-based separation technologies. Concentration polarization, defined as concentration gradient of permeating solute between the bulk and the region near the membrane surface, becomes a limiting factor in pervaporation separations using high-performance membrane materials in VOC removal operations. Thus, the ability to predict the impact of concentration polarization upon process performance is highly desirable in process design and optimization. A mathematical model was developed to illustrate the interplay between concentration polarization and process …

Nitrification Inhibition Using Benzotriazoles, T. Callender, L. C. Davis

Journal of Hazardous Substance Research

The common corrosion inhibitor, 1H-benzotriazole (Bz), found as a component of glycol-based aircraft deicers, and its derivatives, such as 5-chloro-1H-benzotriazole (CBz), 1-hydroxybenzotriazole (HBz), and 5-methyl-1H-benzotriazole (MBz), are all potential nitrification inhibitors (McCarty and Bremner, 1989). The inhibitory effect of benzotriazoles on the nitrification of urea-N fertilizer in agricultural soils was examined over a four-week period. At 10 mg/kg, all compounds tested, except HBz, have the ability to inhibit the nitrification of urea-N fertilizer effectively. Their inhibitory capabilities depend on the structural components of the soil, particularly organic matter (O.M.). In the soil with the largest percent of O.M. (2.3%), inhibition …

Binding Of Silver(I) Ions By Alfalfa Biomass (Medicago Sativa): Batch Ph, Time, Temperature, And Ionic Strength Studies, I. Herrera, J. L. Gardea-Torresdey, K. J. Tiemann, J. R. Peralta-Videa, V. Armendariz, J. G. Parsons

Journal of Hazardous Substance Research

In this study, the use of alfalfa biomass as a cost-effective and environmentally safe technique to recover Ag(I) ions from aqueous solutions is reported. This investigation consisted of batch pH profile, time, temperature, and ionic strength dependence studies. Results showed that alfalfa biomass presented the highest adsorption of Ag(I) ions in the pH range of 7 to 9 with a maximum adsorption capacity of 27.37 mg Ag•g^-1 of dry biomass, evaluated with a solution of 32.4 ppm of Ag(I). Time and temperature studies demonstrated a stable adsorption of Ag(I) ions by the biomass during the first hour of exposure, …

Kansas Case Study Applications Of Nitrogen-15 Natural Abundance Method For Identification Of Nitrate Sources, M. A. Townsend, D. P. Young, S. A. Macko

Journal of Hazardous Substance Research

The nitrogen-15 natural abundance method has been a tool for identifying sources of nitrate contamination in groundwater for almost 30 years. Different ranges of δ¹⁵N in groundwater are associated with different sources such as fertilizer and animal wastes. However processes such as denitrification, nitrification, and volatilization can alter the δ¹⁵N signature.

Use of this method in Kansas has had mixed results. One case study documented in this paper showed the utility of the method in an area with a sandy unsaturated zone and aquifer, a shallow water table, and an animal waste lagoon. The regional groundwater …

Formation And Stability Of Substituted Pyromorphite: A Molecular Modeling Study, Abhijit V. Shevade, Larry Erickson, Gary Pierzynski, Shaoyi Jiang

Journal of Hazardous Substance Research

Soils contaminated with lead pose significant risk to human as well as terrestrial and aquatic ecosystems. Theoretical phase relationships and field observations suggest that the interaction of lead and phosphorus to form pyromorphites Pb₅(PO₄ )₃ X (X= OH_-, Br^-, Cl^-, or F^-) is an important buffer mechanism controlling the migration and fixation of lead in the environment. We report a molecular modeling approach to investigate the formation and stability of the substituted pyromorphites, which involved evaluating the lattice energy of the minerals using ab initio quantum mechanics. The …

Anaerobic Biotransformation Of Aromatic And Polycyclic Aromatic Hydrocarbons In Soil Microcosms: A Review, R. Karthikeyan, A. Bhandari

Journal of Hazardous Substance Research

Industrial activities introduce a wide variety of xenobiotic aromatic compounds into the biosphere. These aromatic and polycyclic aromatic compounds find their way into anaerobic marine and freshwater sediments, saturated aquifers, and waterlogged soils where neither their impact on carbon flow nor their propensity to persist is clearly understood. Although some halogenated aromatic compounds are degraded via anaerobic pathways, anaerobic transformation of aromatics remains limited to a small range of chemicals. This paper reviews anaerobic transformation processes for aromatic compounds, particularly polycyclic aromatic hydrocarbons (PAHs) in soil microcosms. A simplified pathway of PAH biotransformation and a conceptual pathway of PAH degradation …

Phytobuffering Of Lower Chlorinated Benzenes Through Willows At The Ppi Superfund Site, P. B. Jones Jr., R. R. Kommalapati, W. D. Constant

Journal of Hazardous Substance Research

A series of phytobuffering bench-scale experiments using an extraction bed followed by a plant “bioreactor” was performed using streambed sediment from a nearby Superfund site. Experiments consisted of investigating the fate and transport of a mixture of lower chlorinated benzenes (monochlorobenzene, (MCB), 1,2 and 1,3- dichlorobenzene (DCB), and 1,2,4-trichlorobenzene (TCB)) at 10 – 20 ppm sediment loading. These compounds are representative of the degradation products of HCB (hexachlorobenzene) in the Baton Rouge Bayou and Devil’s Swamp area at the Petro Processors Inc. Superfund site. Fast, slow, and cyclic flow rates were used as representative conditions found during rain events in …

Air-Sparging Remediation: A Study On Heterogeneity And Air Mobility Reduction, S. S. Di Julio, A. S. Drucker

Journal of Hazardous Substance Research

Contaminated groundwater is a widespread problem often requiring innovative technologies to remediate. In this study, physical models of the air-sparging process are developed, and contaminant recoveries are compared with predictions from a mathematical model. Initial tests used a very fine, porous media (a glass bead-packed column) to represent relatively homogeneous soil samples. Subsequent testing employed budded core samples taken from an actual site to represent more realistic, heterogeneous samples. 1,1,1 trichloroethane (TCA) was used as the dissolved contaminant to represent benzene, toluene, ethyl benzene, and xylene (BTEX), considered to be gasoline contamination in water. The results obtained, however, can be …

Light Nonaqueous-Phase Liquid Hydrocarbon Weathering At Some Jp-4 Fuel Release Sites, D. H. Kampbell, C. B. Snyder, D. C. Downey, J. E. Hansen

Journal of Hazardous Substance Research

A fuel weathering study was conducted for database entries to estimate natural light, nonaqueousphase liquid weathering and source-term reduction rates for use in natural attenuation models. A range of BTEX weathering rates from mobile LNAPL plumes at eight field sites with known release dates was documented. Freephase fuel BTEX weathering rates varied among sites and were influenced by many factors. First-order weathering rate for five JP-4 fuel sites was 16%/year. Benzene and toluene exhibited higher weathering rates than ethylbenzene and xylene, as expected, because of higher water solubility. The primary weathering mechanism of mobile LNAPL was dissolution. Meaningful determination of …

Effects Of Divalent Metal Cations And Resistance Mechanisms Of The Cyanobacterium Synechococcus Sp. Strain Pcc 7942, G. R. Ybarra, R. Webb

Journal of Hazardous Substance Research

Cyanobacteria exhibit an extraordinary resistance to many environmental factors including nutrient limitation, changes in hydrogen ion concentration, temperature, and light extremes. A better understanding of the biological effects and response mechanisms of cyanobacteria to heavy metal exposure could be used to develop these bacteria for use in bioremediation. Synechococcus sp. strain PCC 7942 expresses messenger RNA for the stress protein GroEL and for the metal-binding protein metallothionein in response to a wide range of divalent metal ion concentrations. Although groEL is expressed at low levels regardless of environmental conditions, a high rate of transcription is initiated within 15 minutes following …

Biosorption And Transformation Of Tetra-Chloroethylene And Trichloroethylene Using Mixed-Species Microbial Mats, W. L. O'Niell, V. A. Nzengung, J. E. Noakes, J. Bender, P. C. Phillips

Journal of Hazardous Substance Research

Microbial mats are naturally occurring assemblages of aquatic organisms capable of sorbing and degrading various organic compounds. Kinetic transformation and sorption experiments were conducted in sealed batch vials, using microbial mats dosed with unlabeled tetrachloroethylene (PCE) and trichloroethylene (TCE) and radiolabeled forms of these compounds ([₁₄C]PCE and [₁₄C]TCE). Results indicated that sorption equilibrium was attained for both chemicals within a few hours. The sorption isotherm was linear, demonstrating that the sorption mechanism was partitioning. PCE was completely degraded in periods as short as 50 days under favorable growth conditions. Samples were also tested for degradation products, …

Transformation Of 2,4, 6-Trinitrotoluene (Tnt) By Immobilized And Resting Cells Of Arthrobacter Sp., A. M. Tope, K. Jamil, T. R. Baggi

Journal of Hazardous Substance Research

Arthrobacter sp. transformed 2,4,6-trinitrotoluene (TNT) into two isomeric monoaminodinitrotoluenes viz, 4-amino-2,6-dinitrotoluene (4-ADNT), 2-amino- 4,6 –dinitrotoluene (2-ADNT) and also 2,4- diamino-6- nitrotoluene (2,4-DANT) under aerobic resting cell conditions. Experiments were carried out at 30° C (±1°C) in phosphate buffer with 60 mg per liter TNT at a pH of 7.2 (±0.2). Complete transformation of TNT occurred within 36 hours, yielding a mixture of monoaminodinitrotoluenes and diaminonitrotoluene. The major component was found to be 4-ADNT. Under the same experimental conditions, transformations were studied using barium alginate immobilized cells of Arthrobacter sp. Appropriate controls were run simultaneously. In both the cases, reactions were …

An Experimental Study Of Phytoremediation Of Methyl-Tert-Butyl Ether (Mtbe) In Groundwater, Q. Zhang, L. C. Davis, L. E. Erickson

Journal of Hazardous Substance Research

The feasibility of phytoremediation of groundwater contamination with methyl-tert-butyl ether (MTBE) was examined experimentally using a six-channel soil system with or without plants. Two bacterial strains capable of degrading MTBE were each added to two out of six channels. A solution of 0.84 mM MTBE was continuously fed into each channel at 1 L/day until a stable MTBE concentration level in the groundwater was established; then the feeding was switched back to distilled water. The channel groundwater effluent MTBE concentration and the soil gas MTBE fluxes were monitored from the beginning of the MTBE solution feeding until no MTBE was …

Phytoextraction Of Metals From Contaminated Soil: A Review Of Plant/Soil/Metal Interaction And Assessment Of Pertinent Agronomic Issues, M. M. Lasat

Journal of Hazardous Substance Research

Phytoremediation is an emerging technology that employs the use of higher plants for the cleanup of contaminated environments. Fundamental and applied research have unequivocally demonstrated that selected plant species possess the genetic potential to remove, degrade, metabolize, or immobilize a wide range of contaminants. Despite this tremendous potential, phytoremediation is yet to become a commercial technology. Progress in the field is precluded by limited knowledge of basic plant remedial mechanisms. In addition, the effect of agronomic practices on these mechanisms is poorly understood. Another limitation lies within the very biological nature of this novel approach. For example, potential for phytoremediation …

Evaluation Of Combustion Processes For Production Of Feedstock Chemicals From Ammonium Sulfate And Ammonium Bisulfate, Y. Liske, S. Kapila, V. Flanigan, P. Nam, S. Lorbert

Journal of Hazardous Substance Research

The combustion of ammonium bisulfate and ammonium sulfate solutions in hydrocarbon/air flames was studied under varied flame conditions. The objective of the study was to optimize the recovery of sulfur value from aqueous waste streams containing these salts. Combustion of ammonium sulfates yielded different sulfur species such as sulfur dioxide (SO₂ ), hydrogen sulfide (H₂S), and carbonyl sulfide (COS). The types of sulfur species obtained and their yields were dependent on the flame stoichiometry. When combustion was carried out in stochiometric flames or in flames with excess oxygen, the sulfur present in the salts was quantitatively converted …

Atmospheric Nanoparticles In Photocatalytic And Thermal Production Of Atmospheric Pollutants, R. R. Chianelli, M. J. Yácaman, J. Arenas, F. Aldape

Journal of Hazardous Substance Research

Atmospheric aerosols which occur above heavily polluted areas such as Mexico City, are characterized and found to be complex materials that have the potential to accelerate important ozone-forming reactions photocatalytically and thermocatalytically. In addition, because the particles are respirable, they may represent a considerable health hazard. The aerosols consist of two intermixed components. The first component consists of amorphous carbonaceous materials of variable composition with "fullerene like" materials dispersed throughout. The second component is an inorganic material consisting of nanoparticles of oxides and sulfides "supported" on clay minerals. This inorganic component has all of the characteristics of an airborne photocatalyst. …

Adsorption Of Toxic Metal Ions From Solution By Inactivated Cells Of Larrea Tridentata Creosote Bush, J. L. Gardea-Torresdey, A. Hernandez, K. J. Tiemann, J. Bibb, O. Rodriguez

Journal of Hazardous Substance Research

Larrea tridentata (creosote bush) is a plant that grows abundantly in the desert environment. This desert plant has been found naturally growing in heavy-metal contaminated soils. Previous experiments showed that the inactivated biomass of creosote bush was able to adsorb Cu(II) ions from aqueous solutions. The copper-binding capacity of the bush biomass that grows in heavy-metal uncontaminated soils was higher than the biomass that grows in heavy-metal contaminated soils. Experiments were performed to determine the ability of creosote bush biomass (grown in heavy metal uncontaminated soils) to adsorb Pb(II), Cd(II), Zn(II), Cr(III), Cr(VI), and Ni(II) ions from aqueous solutions. Batch …

Ability Of Immobilized Cyanobacteria To Remove Metal Ions From Solution And Demonstration Of The Presence Of Metallothionein Genes In Various Strains, J. L. Gardea-Torresdey, J. L. Arenas, N. M. C. Francisco, K. J. Tiemann, R. Webb

Journal of Hazardous Substance Research

Synechococcus sp. PCC 7942 has the ability to grow in mass quantity under ideal conditions; such an ability provides usable biomass at a minimal effort. Using lyophilized biomass grown under normal conditions, Synechococcus was tested for its potential to bind metal ions from solution. Batch experiments have determined the optimum binding pH, time dependency, and metal binding capacities for copper(II), lead(II), nickel(II), cadmium(II), chromium(III), and chromium(VI), along with desorption of the metal bound. The biomass studied showed an affinity for five of the metal ions, with an optimum binding at pH 5. Time dependency studies showed that this cyanobacterium had …

Movement Of Chlorinated Solvents And Other Volatile Organics Through Plants Monitored By Fourier Transform Infrared (Ft-Ir) Spectrometry, L. C. Davis, S. Vanderhoof, J. Dana, K. Selk, K. Smith, B. Goplen, L. E. Erickson

Journal of Hazardous Substance Research

Plants have a large capacity to transfer water from soil to the atmosphere. Soluble contaminants may be carried with that water, with a relative extent of transfer that depends on their octanol-water or organic matter-water partition coefficient. We measured the transfer rate for several solvents that vary in volatility and solubility, including trichloro ethylene, trichloroethane, chloroform, dichloromethane, diethyl ether, and methyl-t-butyl ether. We tested them alone and in several combinations. An extractive Fourier Transform Infrared (FT-IR) Spectrometer (Gasmet, produced by Temet Instruments) was used to measure concentrations in the gas phase above plants which had their root system immersed in …

Physiological Responses Of Switchgrass (Panicum Virgatum L.) To Organic And Inorganic Amended Heavy-Metal Contaminated Chat Tailings, A. L. Youngman

Journal of Hazardous Substance Research

Study plots established at the Galena subsite of the Cherokee County Superfund Site in southeastern Kansas by the U.S. Bureau of Mines in 1990 were examined during the summer of 1996 to determine whether physiological criteria could be used to determine suitability of switchgrass for remediation of heavy-metal contaminated substrates. Switchgrass was chosen because it was the most frequently encountered species on these plots. Treatment plots included a treatment control, an organic residue treatment of 89.6 Mg ha-1 composted cattle manure, and two inorganic fertilizer treatments recommended for either native grass or grass/legume mixtures. Plant response variables were photosynthetic rate, …

Modelling The Role Of Active Biomass On The Fate And Transport Of A Heavy Metal In The Presence Of Root Exudates, K. V. Nedunuri, L. E. Erickson, R. S. Govindaraju

Journal of Hazardous Substance Research

The influence of active biomass in immobilizing heavy metals in the soil rhizosphere is investigated through mechanistic models. The movement of water in the soil is modeled using Richards equation. An advection-dispersion equation, with a sink term for metal uptake by biomass, is used for modeling the fate and transport of lead. This sink term represents the nonlinear kinetics of metal adsorption to the biomass that is partitioned into mobile and stationary fractions within the soil. Transport of the mobile biomass fraction is modeled by an advection-dispersion equation, with a source term that is based on Monod growth kinetics, and …

Modeling The Fate Of Toluene In A Chamber With Alfalfa Plants: 2. Numerical Results And Comparison Study, M. Narayanan, J. C. Tracy, L. C. Davis, L. E. Erickson

Journal of Hazardous Substance Research

Investigations were conducted in a chamber to study the role of alfalfa plants in bioremediating toluene. Modeling and experimental results indicate that in situ bioremediation of toluene in the presence of plants is feasible and economical. This is primarily due to evapotranspiration which greatly enhances the vertical transport of dissolved contaminants from the saturated zone to the rhizosphere, thereby increasing the possibility of aerobic degradation. The fate of toluene was simulated and monitored for groundwater contaminated with toluene at saturated concentrations. FT-IR instrumentation was used to monitor toluene in the headspace gas of the vegetated chamber. Overall mass balance, based …

Effect Of Vegetation On Transport Of Groundwater And Non-Aqueous Phase Liquid Contaminants, Q. Zhang, L. C. Davis, L. E. Erickson

Journal of Hazardous Substance Research

An aquifer model system was established to examine and delineate the presence, fate and transport of nonaqueous-phase liquid (NAPL) contaminants. The system consists of six independent channels with identical dimensions. The channels were constructed with steel bottoms, side panels, and end panels. Trichloroethylene (TCE) was selected as a representative compound to model NAPL groundwater contaminants in the saturated zone of the aquifer.

The flow regime of groundwater in the saturated zone was investigated by conducting a bromide tracer experiment. The movement of TCE in both horizontal and vertical directions was studied by monitoring the ground- water effluent stream and the …