Capillary electrophoresis with ultraviolet detection (CE-UV) and laser-induced fluorescence detection (CE-LIF) was used for analysis of a group of herbicides that have widespread use in the USA. CE-UV was employed for simultaneous... more
Capillary electrophoresis with ultraviolet detection (CE-UV) and laser-induced fluorescence detection (CE-LIF) was used for analysis of a group of herbicides that have widespread use in the USA. CE-UV was employed for simultaneous determination of atrazine, simazine, ...
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Research Interests: Chemistry, Kinetics, Medicine, Multidisciplinary, Calibration, and 15 moreMethanol, Regression Analysis, Polychlorinated Biphenyls, Partition Coefficient, Polychlorinated Biphenyl, Mathematical Model, Hydrophobicity, Regression Model, Polydimethylsiloxane, Linear Regression, Aqueous Solution, Silicones, Environment, Rate Constant, and Distribution coefficient
Research Interests: Endocrinology, Animal Behavior, Anxiety, Estrogen Receptor, Biological Sciences, and 15 moreInternal Medicine, Animals, Hormones, Estrogen, Male, Analysis of Variance, Elevated Plus Maze, ANXIETY, Anxiolytic, Experimental Methodology, Agonist, Estrogen receptor alpha, isoflavones, Estrogen Receptor beta, and Male rat
Research Interests: Biology, Medicine, Multidisciplinary, Multivariate Analysis, Cell line, and 14 morePopulation, Humans, Pesticide, Pesticides, Genotype, Pesticide Residue, Genetic Polymorphism, Reproducibility of Results, European Continental Ancestry Group, Cell Survival, Hazardous Substances, Environment, Complex Mixtures, and Cell culture techniques
The solubility of covellite has been measured in 0.5-2.0 M NaCl at 25°C. Solutions containing various concentrations of total sulfide and zerovalent sulfur have been studied over the pH range 6-11. The data are interpreted in terms of the... more
The solubility of covellite has been measured in 0.5-2.0 M NaCl at 25°C. Solutions containing various concentrations of total sulfide and zerovalent sulfur have been studied over the pH range 6-11. The data are interpreted in terms of the following complexes, for which stability constants are presented: CuS(HS) 2 2- , CuS(HS) 3 3- , Cu(S 5 ) 2 3-
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ABSTRACT
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Nonaqueous capillary electrophoresis (NACE) is a chemical separation technique that has grown in popularity over the past few years. In this report, we focus on the combination of heteroconjugation and deprotonation in the NACE separation... more
Nonaqueous capillary electrophoresis (NACE) is a chemical separation technique that has grown in popularity over the past few years. In this report, we focus on the combination of heteroconjugation and deprotonation in the NACE separation of phenols using acetonitrile (ACN) as the buffer solvent. By preparing various dilute buffers consisting of carboxylic acids and tetrabutylammonium hydroxide in ACN, selectivity may
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Research Interests: Environmental Science, Soil, Mass Spectrometry, Agriculture, Environmental Monitoring, and 13 moreCosta Rica, Medicine, Multidisciplinary, Nitriles, Musa, Liquid Chromatography, Time Factors, Tropical Climate, Extreme Weather Condition, Chlorothalonil, Plant Leaves, Aerial Application, and Fungicide
The ability of nonylphenol polyethoxylate (nonylphenyl polyethylene glycol, NPPG) to alter the metabolic elimination of testosterone and elicit reproductive toxicity to Daphnia magna was assessed. NPPG (5.0 mg/liter) inhibited the... more
The ability of nonylphenol polyethoxylate (nonylphenyl polyethylene glycol, NPPG) to alter the metabolic elimination of testosterone and elicit reproductive toxicity to Daphnia magna was assessed. NPPG (5.0 mg/liter) inhibited the elimination of testosterone as glucose and sulfate conjugates, but had minimal effect on the rate of elimination of oxido-reduced and hydroxylated derivatives of the steroid hormone. This exposure concentration of NPPG also approximated the acute threshold-effect concentration and the chronic value for daphnids. Results demonstrated that NPPG qualitatively elicits similar effects on the metabolic elimination of testosterone by daphnids as previously characterized with its degradation product 4-nonylphenol. Unlike 4-nonylphenol, significant chronic toxicity of NPPG, due to effects on steroid elimination processes, was not evident. Results from the present study provide no indication that concentrations of nonylphenol polyethoxylates typically measured in the environment pose a risk of chronic toxicity to invertebrates.
Research Interests: Chemistry, Biology, Daphnia, Medicine, Environmental Sciences, and 15 moreGlucose, Female, Animals, Nonylphenol, CHEMICAL SCIENCES, Phenols, Polyethylene Glycol, Reproductive Toxicity, Environmental Safety, Daphnia Magna, Detergents, Culture Media, Chronic Toxicity, Sulfates, and Medical and Health Sciences
Research Interests: Chemistry, Chromatography, Mass Spectrometry, Medicine, Multidisciplinary, and 15 moreBiodegradation, Pesticide, Fungicides, Nitriles, Pesticides, Atmospheric Pressure, Musa, Gas Chromatography, Chemical Analysis, Liquid Chromatography, LC MS, Metabolite, Chlorothalonil, Fungicide, and limit of detection
Research Interests: Biology, Medicine, Biological Sciences, Environmental Sciences, Fungicides, and 15 moreBivalvia, Animals, North America, CHEMICAL SCIENCES, Fresh water, Larva, Environmental Toxicology and Chemistry, Mussel, High Sensitivity, Acute Toxicity, Atrazine, Environmental, Chronic Toxicity, Chlorothalonil, and Fipronil
Water scarcity increases the likelihood of irrigating food crops with municipal wastewater that may pose potential dietary risks of regulated and non-regulated organic chemical uptake to edible plant tissues. Only a few studies have used... more
Water scarcity increases the likelihood of irrigating food crops with municipal wastewater that may pose potential dietary risks of regulated and non-regulated organic chemical uptake to edible plant tissues. Only a few studies have used high resolution mass spectrometry (HRMS) to assess the uptake of chemicals of concern into food crops. This study used non-target and suspect-screening analyses to compare total chemical features, tentatively identified chemicals (TICs), and EPA ToxCast chemicals in soybean plants and passive samplers exposed to five different irrigation sources that were collected from an agricultural watershed during mild drought conditions. Secondary-treated municipal wastewater effluent, two surface waters, two ground waters, and deionized municipal tap water were used for two hydroponic experiments: soybean roots and shoots and Composite Integrative Passive Samplers (CIPS) harvested after fourteen days of exposure and soybeans after fifty-six days. CIPS were sealed in separate glass amber jars to evaluate their efficacy to mimic chemical features, TICs, and ToxCast chemical uptake in plant roots, shoots, and beans. Total soybean biomass and water use were greatest for tap water, municipal wastewater, and surface water downstream of the municipal wastewater facility relative to groundwater samples and surface water collected upstream of the wastewater facility. ToxCast chemicals were ubiquitous across watershed irrigation sources in abundance, chemical use category, and number. Wastewater-exposed soybeans had the fewest extractable TICs in plant tissues of all irrigation sources. More ToxCast chemicals were identified in CIPS than extracted from irrigation sources by solid phase extraction. ToxCast chemicals in beans and CIPS were similar in number, chemical use category, and log Kow range. CIPS appear to serve as a useful surrogate for ToxCast chemical uptake in beans, the edible food product.
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On September 14, 2018, Hurricane Florence delivered ~686 mm rainfall to a 106 km2 watershed in coastal North Carolina, USA. A forested land treatment site comprises one third of the watershed wherein municipal wastewater effluent is... more
On September 14, 2018, Hurricane Florence delivered ~686 mm rainfall to a 106 km2 watershed in coastal North Carolina, USA. A forested land treatment site comprises one third of the watershed wherein municipal wastewater effluent is spray-irrigated onto 8.9 km2 of forest. This communication provides insight for land treatment function under excess water duress as well as changes in organic chemical composition in on- and off-site waters before (June 2018) and after (September & December 2018) Hurricane Florence's landfall. We compare the numbers and relative abundances of chemical features detected using suspect screening high resolution mass spectrometry in waste-, ground-, and surface water samples. Values for upstream and receiving waters in September were lower than for sampling events in June and December, indicating an expected dilution effect across the watershed. Chemical diversity was greatest for all surface water samples in December, but only upstream surface water showed a dramatic five-fold increase in relative chemical abundance. Chemical abundance in on-site water and downstream surface water was equal to or lower than the September storm dilution effect. These data suggest that the land treatment system is functionally and hydrologically robust to extreme storm events and contributed to dilution of upstream chemical reservoirs for downstream receiving waters for months after the storm. Similar systems may embody one water reuse strategy robust to the increasing occurrence of extreme precipitation events.
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Research Interests: Biology, Medicine, Biological Sciences, Environmental Sciences, Fungicides, and 15 moreBivalvia, Animals, North America, CHEMICAL SCIENCES, Fresh water, Larva, Environmental Toxicology and Chemistry, Mussel, High Sensitivity, Acute Toxicity, Atrazine, Environmental, Chronic Toxicity, Chlorothalonil, and Fipronil
Cyclodextrin-modified micellar electrokinetic chromatography was applied successfully to the enantiomeric and isomeric separation of 7 commonly used pesticides (propiconazole, bioallethrin, fenpropathrin, phenothrin, bitertanol,... more
Cyclodextrin-modified micellar electrokinetic chromatography was applied successfully to the enantiomeric and isomeric separation of 7 commonly used pesticides (propiconazole, bioallethrin, fenpropathrin, phenothrin, bitertanol, triadimenol, and dimethomorph). Commercially available surfactants used alone or in combination with cyclodextrins were evaluated for separation of the enantiomers/isomers of the 7 pesticides. The enan-tiomers/isomers of the pesticides used in this study were baseline resolved with resolutions of ≥1.5. The resolution was found to depend on the type of surfactant and cyclodextrin employed in the running buffer. In the case of propiconazole and dimethomorph, baseline resolution was also achieved by adding sodium cholate (a chiral surfactant) alone to the running buffer. Analysis of fortified water samples yielded recoveries ranging from 45 to 89% and method detection limits ranging from 0.18 to 2.1 ppb. The reported capillary electrophoresis methods are simple, rapid, and reproducible.
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Research Interests: Chemical Engineering, Chemistry, Analytical Chemistry, Chromatography, Fluorescence, and 15 moreCapillary electrophoresis, Medicine, Micelles, Lasers, Animals, Fishes, Marine Toxins, Laser Induced Fluorescence, Environmental Analysis, Neurotoxins, Electrophoresis, Derivatization, Biochemistry and cell biology, Molecular Structure, and micellar electrokinetic chromatography
Vrtebrates and invertebrates metabolize testosterone to a variety of less‐polar derivatives that elicit varying degrees of androgenicity as well as polar elimination products. We have developed a model, using the cladoceran Daphnia magna,... more
Vrtebrates and invertebrates metabolize testosterone to a variety of less‐polar derivatives that elicit varying degrees of androgenicity as well as polar elimination products. We have developed a model, using the cladoceran Daphnia magna, with which the ability of xenobiotics to alter steroid hormone metabolism can be assessed and possible physiologic consequences evaluated during a 3‐week assay. This model was used to assess the effects of the xenoestrogen 4‐nonylphenol on steroid‐metabolic processes. Exposure of daphnids to 100 μg/L 4‐nonylphenol for 48 h caused a significant increase in the accumulation of radioactivity derived from [14C]testosterone provided to the exposure media. More definitive analyses demonstrated that both 25 and 100 μg/L 4‐nonylphenol disrupted components of the testosterone metabolic pathway that would lead to a decrease in the metabolic elimination of testosterone and an increase in the accumulation of androgenic derivatives. Exposure of daphnids to 100 μg/L 4‐nonylphenol significantly decreased fecundity of the organisms while having no effect on survival of the parental organisms. Comparison of metabolic and reproductive effects of 4‐nonylphenol revealed that 71 μg/L, the reproductive chronic value, would reduce the metabolic elimination of testosterone by approximately 50%. This relationship is consistent with that which we have reported for other toxicants and identifies a mechanism, in addition to estrogenicity, that may contribute to the reproductive toxicity of this compound.
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Page 1. Developing national sediment quality criteria Epl&rimpartitioning of contaminants ma means of evaluating sediment quality To ensure that aqueous concentrations of contaminants are within acceptable liits for the protection... more
Page 1. Developing national sediment quality criteria Epl&rimpartitioning of contaminants ma means of evaluating sediment quality To ensure that aqueous concentrations of contaminants are within acceptable liits for the protection ...
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Page 1. Research Articles 1 Organochlorine Pesticides and Polychlorinated Biphenyls © ecomed publishers, D-86899 Landsberg, Germany and Ft. Worth/TX, USA • Tokyo, Japan • Mumbai, India • Seoul, Korea ESPR – Environ. Sci. & Pollut.... more
Page 1. Research Articles 1 Organochlorine Pesticides and Polychlorinated Biphenyls © ecomed publishers, D-86899 Landsberg, Germany and Ft. Worth/TX, USA • Tokyo, Japan • Mumbai, India • Seoul, Korea ESPR – Environ. Sci. & Pollut. Res. 7 (2000) Research Articles ...
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Non-targeted analysis (NTA) is a rapidly evolving analytical technique with numerous opportunities to improve and expand instrumental and data analysis methods. In this work, NTA was performed on eight synthetic mixtures containing 1264... more
Non-targeted analysis (NTA) is a rapidly evolving analytical technique with numerous opportunities to improve and expand instrumental and data analysis methods. In this work, NTA was performed on eight synthetic mixtures containing 1264 unique chemical substances from the U.S. Environmental Protection Agency’s Non-Targeted Analysis Collaborative Trial (ENTACT). These mixtures were analyzed by atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) using both positive and negative polarities for a total of four modes. Out of the 1264 ENTACT chemical substances, 1116 were detected in at least one ionization mode, 185 chemicals were detected using all four ionization modes, whereas 148 were not detected. Forty-four chemicals were detected only by APCI, and 181 were detected only by ESI. Molecular descriptors and physicochemical properties were used to assess which ionization type was preferred for a given compound. One ToxPrint substructure (naphthalene group) was found to be enriched in compounds only detected using APCI, and eight ToxPrints (e.g., several alcohol moieties) were enriched in compounds only detected using ESI. Examination of physicochemical parameters for ENTACT chemicals suggests that those with higher aqueous solubility preferentially ionized by ESI−. While ESI typically detects a larger number of compounds, APCI offers chromatograms with less background, fewer co-elutions, and additional chemical space coverage, suggesting both should be considered for broader coverage in future NTA research.
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... William MacCrehan and Damian Shea1 ... sulfide HS' product dissiirrilatory S04= salt marsh (12) reduction (3,30,40,44); energy fjord (6) resource (3); pyrite deposition (29) coastal (51) coastal (10) salt marsh (11) salt... more
... William MacCrehan and Damian Shea1 ... sulfide HS' product dissiirrilatory S04= salt marsh (12) reduction (3,30,40,44); energy fjord (6) resource (3); pyrite deposition (29) coastal (51) coastal (10) salt marsh (11) salt marsh (58) estuary (*) ...
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Research Interests: Population and Toad
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Background The teleost fish Fundulus heteroclitus inhabit estuaries heavily polluted with persistent and bioaccumulative chemicals. While embryos of parents from polluted sites are remarkably resistant to toxic sediment and develop... more
Background The teleost fish Fundulus heteroclitus inhabit estuaries heavily polluted with persistent and bioaccumulative chemicals. While embryos of parents from polluted sites are remarkably resistant to toxic sediment and develop normally, embryos of parents from relatively clean estuaries, when treated with polluted sediment extracts, are developmentally delayed, displaying deformities characteristic of pollution-induced embryotoxicity. To gain insight into parental effects on sensitive and resistant phenotypes during late organogenesis, we established sensitive, resistant, and crossed embryo families using five female and five male parents from relatively clean and predominantly PAH-polluted estuaries each, measured heart rates, and quantified individual embryo expression of 179 metabolic genes. Results Pollution-induced embryotoxicity manifested as morphological deformities, significant developmental delays, and altered cardiac physiology was evident among sensitive embryos res...
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This chapter describes a case study of place-based education in action called the Bennett’s Millpond Environmental Learning Project. The work sought to engage high school students and teachers in place-based, collaborative research... more
This chapter describes a case study of place-based education in action called the Bennett’s Millpond Environmental Learning Project. The work sought to engage high school students and teachers in place-based, collaborative research experiences related to environmental sustainability. Results from a formal evaluation of the project are discussed. Several themes related to science teacher education and professional development that emerged from the data are presented, including teacher development as researchers, teacher development of collaborations with the community, and teacher use of technology to facilitate learning and outreach. An argument is provided for the importance of technology as a mediator that allows both teachers and students to easily move between local place-based environmental sustainability issues and global worldviews.
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ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) may drive remediation at impacted soil or sediment sites. Current equations for calculating the PAH concentrations in soil that are protective of underlying groundwater (i.e., soil... more
ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) may drive remediation at impacted soil or sediment sites. Current equations for calculating the PAH concentrations in soil that are protective of underlying groundwater (i.e., soil screening levels, or SSLs) generally assume a three-phase partitioning model, wherein PAHs partition among the soil matrix, porewater, and pore air. This simplified model does not consider the oil phase, and therefore overestimates the dissolved PAH concentration, and consequently, overpredicts the mobility and toxicity of PAHs to receptors especially when the source of PAHs is oil. This results in unnecessarily stringent cleanup goals and adds to the cost of treatment and management of impacted soils. Complicating factors leading to the overestimation of dissolved PAH are that oil weathering (1) decreases to the effective solubility of the lower molecular weight PAHs, and (2) the presence of the oil itself increases PAH retention in the oil phase, thereby reducing aqueous/dissolved PAH concentrations. This is particularly important when oil is both the source and the factor controlling its solubility. In this paper, we have incorporated additional partitioning factors into existing SSL equations to capture the impact of oil weathering on PAH partitioning: The oil-water partitioning coefficient (KOIL ) for crude oils was measured at different stages of weathering using a passive sampling device (PSD). Results confirm that current methods for deriving SSLs are highly conservative and that the aqueous concentrations and mobility of PAHs are lower in soils and sediments that contain weathered oils. Thus, the mobility of PAHs in historically impacted soils is much lower than what is assumed when calculating SSLs for soil-leaching-to-groundwater scenarios.
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The manifestation of differential metabolic profiles combined with the perturbation of physiological indicators in M. aeruginosa upon silver nanoparticle exposure is taken as evidence of damage to photosynthesis and membranes.
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Forest-water reuse systems infiltrate municipal, industrial, and agricultural wastewaters through forest soils to shallow aquifers that ultimately discharge to surface waters. Their ability to mitigate regulated nutrients, metals, and... more
Forest-water reuse systems infiltrate municipal, industrial, and agricultural wastewaters through forest soils to shallow aquifers that ultimately discharge to surface waters. Their ability to mitigate regulated nutrients, metals, and organic chemicals is well known, but the fate of non-regulated chemicals in these systems is largely unstudied. This study quantified 33 pharmaceuticals and personal care products (PPCPs) in soils, groundwaters, and surface waters in a 2000-hectare forest that receives ~1200mm/year of secondary-treated, municipal wastewater in addition to natural rainfall (~1300mm/year). This forest-water reuse system does contribute PPCPs to soils, groundwater, and surface waters. PPCPs were more abundant in soils versus underlying groundwater by an order of magnitude (5-10ng/g summed PPCPs in soil and 50-100ng/L in groundwater) and the more hydrophobic chemicals were predominant in soil over water. PPCP concentrations in surface waters were greater at the onset of si...
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Cyclodextrin-modified micellar electrokinetic chromatography was applied successfully to the enantiomeric and isomeric separation of 7 commonly used pesticides (propiconazole, bioallethrin, fenpropathrin, phenothrin, bitertanol,... more
Cyclodextrin-modified micellar electrokinetic chromatography was applied successfully to the enantiomeric and isomeric separation of 7 commonly used pesticides (propiconazole, bioallethrin, fenpropathrin, phenothrin, bitertanol, triadimenol, and dimethomorph). Commercially available surfactants used alone or in combination with cyclodextrins were evaluated for separation of the enantiomers/isomers of the 7 pesticides. The enan-tiomers/isomers of the pesticides used in this study were baseline resolved with resolutions of ≥1.5. The resolution was found to depend on the type of surfactant and cyclodextrin employed in the running buffer. In the case of propiconazole and dimethomorph, baseline resolution was also achieved by adding sodium cholate (a chiral surfactant) alone to the running buffer. Analysis of fortified water samples yielded recoveries ranging from 45 to 89% and method detection limits ranging from 0.18 to 2.1 ppb. The reported capillary electrophoresis methods are simple...