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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Emerging Chemicals And Analytical Methods (2006), Matthew Morley, Daniel Snow, Chad Cecrle, Patrick Denning, Lindsey Miller
Emerging Chemicals And Analytical Methods (2006), Matthew Morley, Daniel Snow, Chad Cecrle, Patrick Denning, Lindsey Miller
Daniel D Snow
This review summarizes peer-reviewed literature related to analysis, occurrence, and fate of emerging chemical contaminants in the water environment. The review focuses on the following broad categories of emerging contaminants: pharmaceuticals and personal care products (PPCPs); endocrine disrupting compounds (EDCs), including hormones, surfactants, and plasticizers; and brominated flame retardants (BFRs). Although many of the cited articles refer to multiple types of contaminants (particularly hormones and pharmaceuticals), each article is summarized in only one section. Articles pertaining to specific treatment methods, risk assessments, or biological effects are not included in this review, and articles covering disinfection byproducts (DBPs), fluorinated compounds, and …
Remediating Rdx-Contaminated Ground Water With Permanganate: Laboratory Investigations For The Pantex Perched Aquifer, M. Adam, Steven Comfort, Matthew Morley, Daniel Snow
Remediating Rdx-Contaminated Ground Water With Permanganate: Laboratory Investigations For The Pantex Perched Aquifer, M. Adam, Steven Comfort, Matthew Morley, Daniel Snow
Daniel D Snow
Ground water beneath the U.S. Department of Energy Pantex Plant is contaminated with the high explosive RDX (hexahydro-1,3,5- trinitro-1,3,5 triazine). The USDOE Innovative Treatment and Remediation Demonstration (ITRD) program identified in situ oxidation by permanganate as a technology fit for further investigation. We evaluated the efficacy of KMnO4 to transform and mineralize RDX by determining degradation kinetics and carbon mass balances using 14C-RDX. Aqueous RDX solutions (2–5 mg L–1) and RDX-contaminated slurries (50% solids, w/v) were treated with KMnO4 at 1000, 2000, 4000, and 20,000 mg L–1. Treating an aqueous RDX solution of 2.8 mg L–1 with 20,000 mg KMnO4 …
Occurrence Of Sulfonamide Antimicrobials In Private Water Wells In Washington County, Idaho, Usa, Angela Batt, Daniel Snow, Diana Aga
Occurrence Of Sulfonamide Antimicrobials In Private Water Wells In Washington County, Idaho, Usa, Angela Batt, Daniel Snow, Diana Aga
Daniel D Snow
County (Weiser, Idaho) were collected to assess the impact of a nearby confined animal feeding operation (CAFO) on the quality of the local groundwater. All six samples were found contaminated by two veterinary antimicrobials, sulfamethazine (at concentrations from 0.076 to 0.22 μg/l) and sulfadimethoxine (at concentrations from 0.046 to 0.068 μg/l). These groundwater samples also contained elevated concentrations of nitrate and ammonium. Three of the sampled wells have nitrate levels that exceeded the maximum contaminant level set by the US Environmental Protection Agency for drinking water, with nitrate concentration as high as 39.1 mg/l. All but one well showed nitrate, …
Herbicides In Ground Water Beneath Nebraska’S Management Systems Evaluation Area, Roy F. Spalding, Mary Exner, Daniel Snow, David Cassada, Mark Burbach, Stephen Monson
Herbicides In Ground Water Beneath Nebraska’S Management Systems Evaluation Area, Roy F. Spalding, Mary Exner, Daniel Snow, David Cassada, Mark Burbach, Stephen Monson
Daniel D Snow
Profiles of ground water pesticide concentrations beneath the Nebraska Management Systems Evaluation Area (MSEA) describe the effect of 20 years of pesticide usage on ground water in the central Platte Valley of Nebraska. During the 6-yr (1991–1996) study, 14 pesticides and their transformation products were detected in 7848 ground water samples from the unconfined water table aquifer. Triazine and acetamide herbicides applied on the site and their transformation products had the highest frequencies of detection. Atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] concentrations decreased with depth and ground water age determined with 3H/3He dating techniques. Assuming equivalent atrazine …
Anaerobic Biodegradation Of Rdx And Tce: Single- And Dual-Contaminant Batch Tests, Travis S. M. Young, Matthew C. Morley, Daniel D. Snow
Anaerobic Biodegradation Of Rdx And Tce: Single- And Dual-Contaminant Batch Tests, Travis S. M. Young, Matthew C. Morley, Daniel D. Snow
Daniel D Snow
Several sites in the United States have groundwater contaminated with mixtures of high explosives and chlorinated solvents. This research examined the ability of two microbial cultures (anaerobic sludge and a facultative enrichment culture) to biodegrade single- and dual-contaminant mixtures of trichloroethene (TCE) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under anaerobic conditions. In single component batch tests, both cultures degraded 0.6–1 mg RDX/L and its nitroso metabolites to below detection limits in <7 days. During initial 9-day TCE biodegradation tests, the anaerobic sludge did not transform TCE, whereas the facultative culture transformed approximately 10% of the initial 1.4 mg TCE/L. Prior to dual-contaminant batch …
Transformation Of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (Rdx) By Permanganate, Chanat Chokejaroenrat, Steven Comfort, Clifford Harris, Daniel Snow, David Cassada, Chainarong Sakulthaew, Tunlawit Satapanajaru
Transformation Of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (Rdx) By Permanganate, Chanat Chokejaroenrat, Steven Comfort, Clifford Harris, Daniel Snow, David Cassada, Chainarong Sakulthaew, Tunlawit Satapanajaru
Daniel D Snow
The chemical oxidant permanganate (MnO4−) has been shown to effectively transform hexa-hydro-1,3,5-trinitro-1,3,5-triazine (RDX) at both the laboratory and fieldscales. We treated RDX with MnO4− with the objective of quantifying the effects of pH and temperature on destruction kinetics and determining reaction rates. A nitrogen mass balance and the distribution of reaction products were used to provide insight into reaction mechanisms. Kinetic experiments (at pH ~7, 25 °C) verifiedthat RDX−MnO4− reaction was first-order with respect to MnO4− and initial RDX concentration (second-order rate: 4.2 × 10−5 M−1 s−1). Batch experiments showed that choice of quenching agents (MnSO4, MnCO3, and H2O2) influenced …
Emerging Chemicals And Analytical Methods (2005), Matthew C. Morley, Daniel D. Snow, Vince Kuppig
Emerging Chemicals And Analytical Methods (2005), Matthew C. Morley, Daniel D. Snow, Vince Kuppig
Daniel D Snow
Emerging contaminants in the water environment continues to be a strong research focus, as evidenced by the abundance of material published during 2004. This review summarizes peer-reviewed literature pertinent to the field of environmental engineering and science and related to analysis, occurrence, and fate of emerging chemical contaminants in the water environment, focusing on the following broad categories of emerging organic contaminants: antibiotics and pharmaceuticals; personal care products ingredients (PCPIs), endocrine disrupting compounds (EDCs), halogenated compounds (particularly brominated and fluorinated compounds), and disinfection byproducts (DBPs). To maintain this focus, articles pertaining specifically to human and ecological toxicity, bioconcentration or bioaccumulation, …
Detection, Occurrence, And Fate Of Emerging Contaminants In Agricultural Environments (2009), Daniel D. Snow, Shannon L. Bartelt-Hunt, Shannon Devivo, Samuel Saunders, David A. Cassada
Detection, Occurrence, And Fate Of Emerging Contaminants In Agricultural Environments (2009), Daniel D. Snow, Shannon L. Bartelt-Hunt, Shannon Devivo, Samuel Saunders, David A. Cassada
Daniel D Snow
Frequently studied environmental contaminants in agricultural systems include nutrients, sediments, and pesticides. These groups of contaminants typically occur at easily measured concentrations in surface run-off in agricultural watersheds. Nutrients, especially nitrogen, and pesticides have also been shown to impact ground water quality in areas susceptible to contamination. Less well-known are environmental impacts of newer classes of contaminants such as pharmaceuticals, steroids, antibiotic-resistance genes and prion proteins. These “emerging” contaminants clearly have potential to enter the environment and cause known or suspected adverse ecological or human health effects. Release of these contaminants to the environment often has occurred for quite some …
Field-Scale Cleanup Of Atrazine And Cyanazine Contaminated Soil With A Combined Chemical-Biological Approach, Manmeet Waria, Steven Comfort, Sathaporn Onanong, T. Satapanajaru, Hardiljeet Boparai, C. Harris, Daniel Snow, David Cassada
Field-Scale Cleanup Of Atrazine And Cyanazine Contaminated Soil With A Combined Chemical-Biological Approach, Manmeet Waria, Steven Comfort, Sathaporn Onanong, T. Satapanajaru, Hardiljeet Boparai, C. Harris, Daniel Snow, David Cassada
Daniel D Snow
A former agrichemical dealership in western Nebraska was suspected of having contaminated soil. Our objective was to characterize and remediate the contaminated site by a combined chemical-biological approach. This was accomplished by creating contour maps of the on-site contamination, placing the top 60 cm of contaminated soil in windrows and mixing with a mechanical high-speed mixer. Homogenized soil containing both atrazine [6-chloro-N-ethyl-N´-isopropyl-1,3,5-triazine- 2,4-diamine] and cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5- triazin-2-yl] amino]-2-methylpropanenitrile} was then used in laboratory investigations to determine optimum treatments for pesticide destruction. Iron suspension experiments verified that zerovalent iron (Fe0) plus ferrous sulfate (FeSO4•7H2O) removed more than 90% of both atrazine …
Herbicide Loading To Shallow Ground Water Beneath Nebraska’S Management Systems Evaluation Area, Roy F. Spalding, Darrell G. Watts, Daniel D. Snow, David A. Cassada, Mary E. Exner, James S. Schepers
Herbicide Loading To Shallow Ground Water Beneath Nebraska’S Management Systems Evaluation Area, Roy F. Spalding, Darrell G. Watts, Daniel D. Snow, David A. Cassada, Mary E. Exner, James S. Schepers
Daniel D Snow
Better management practices can counter deterioration of ground water quality. From 1991 through 1996 the influence of improved irrigation practices on ground water pesticide contamination was assessed at the Nebraska Management SystemsEvaluation Area. Three 13.4-ha corn (Zea mays L.) fields were studied: a conventional furrow-irrigated field, a surge-irrigated field and a center pivot–irrigated field, and a center pivot–irrigated alfalfa (Medicago sativa L.) field. The corn fields received one identical banded application of Bicep (atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] _ metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide]) annually; the alfalfa field was untreated. Ground water samples were collected three times annually from 16 depths of 31 multi-level samplers. …
Detection, Occurrence And Fate Of Emerging Contaminants In Agricultural Environments (2008), Daniel D. Snow, Shannon L. Bartelt-Hunt, Samuel E. Saunders, Shannon L. Devivo, David A. Cassada
Detection, Occurrence And Fate Of Emerging Contaminants In Agricultural Environments (2008), Daniel D. Snow, Shannon L. Bartelt-Hunt, Samuel E. Saunders, Shannon L. Devivo, David A. Cassada
Daniel D Snow
Agricultural settings are affected by a unique set of environmental contaminants typically associated with land use. Nutrients and sediments from run-off and erosion have historically been, and continue to be, studied and understood with respect to their impacts to aquatic environments. Studies involving newer classes of contaminants, such as pharmaceuticals and steroids, are becoming more prevalent as methods for measuring these compounds become available. These “emerging” contaminants clearly have potential to enter the environment and cause known or suspected adverse ecological or human health effects. Release of these contaminants to the environment has occurred for quite some time, but methods …
The Occurrence Of Illicit And Therapeutic Pharmaceuticals In Wastewater Effluent And Surface Waters In Nebraska, Shannon L. Bartelt-Hunt, Daniel D. Snow, Teyona Damon, Johnette Shockley, Kyle Hoagland
The Occurrence Of Illicit And Therapeutic Pharmaceuticals In Wastewater Effluent And Surface Waters In Nebraska, Shannon L. Bartelt-Hunt, Daniel D. Snow, Teyona Damon, Johnette Shockley, Kyle Hoagland
Daniel D Snow
Passive samplers were used to develop semi-quantitative estimates of pharmaceutical concentrations in receiving waters influenced by wastewater effluent. The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant …