- 806-834-1587
Todd Anderson
Texas Tech University, Environmental Toxicology, Faculty Member
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Research Interests: Biology, Environmental Monitoring, Pesticide Residues, Environmental Pollution, Medicine, and 15 moreMultidisciplinary, Female, Animals, Male, Belize, Crocodile, Endosulfan, Sample Size, Environmental Pollutants, Environmental, Confidence Interval, Crocodylus, Confidence Level, Statistical evaluation, and Wet weight
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Research Interests: Environmental Science, Biomimetics, Carbon Nanotube, Environmental Chemistry, Medicine, and 13 moreMultidisciplinary, Adsorption, Animals, Physical sciences, Oligochaeta, Bioavailability, CHEMICAL SCIENCES, Polycyclic aromatic hydrocarbons (PAHs), Biological Availability, Soil Water, Soil Pollutants, Nanotubes Carbon, and Molecular Structure
Research Interests: Environmental Science, Environmental Monitoring, Environmental Chemistry, Medicine, Biological Sciences, and 12 moreAquatic Ecosystem, Environmental Sciences, Humans, Animals, Fishes, Louisiana, Contamination, CHEMICAL SCIENCES, Seasons, Biota, Environmental Toxicology and Chemistry, and pelagic zone
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Abstract Natural perchlorate (ClO4-) exists in many places on Earth, in lunar regolith, meteorites, and on the surface of Mars. Terrestrial natural ClO4- has widely variable Cl and O stable isotopic compositions (δ37Cl, δ18O, Δ17O). The... more
Abstract Natural perchlorate (ClO4-) exists in many places on Earth, in lunar regolith, meteorites, and on the surface of Mars. Terrestrial natural ClO4- has widely variable Cl and O stable isotopic compositions (δ37Cl, δ18O, Δ17O). The δ18O and Δ17O values of ClO4- from the most hyper-arid locations co-vary. ClO4- from less arid areas has relatively little 17O excess and poor Δ17O-δ18O correlation. ClO4- from the Atacama Desert has unusually low δ37Cl (
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Uptake and accumulation kinetics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its two major N-nitroso metabolites, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), in... more
Uptake and accumulation kinetics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its two major N-nitroso metabolites, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), in earthworms was investigated. Results indicated that RDX and its N-nitroso metabolites were rapidly absorbed into earthworms (Eisenia fetida), reaching the highest concentrations within a few days. Accumulation of RDX was greater than its N-nitroso metabolites, as evidenced by a higher bioconcentration factor (BCF); BCFs were 1.86, 0.39, and 0.05 for RDX, MNX, and TNX, respectively. RDX and its N-nitroso metabolites were also rapidly eliminated from the earthworm and/or transformed to other metabolites, as evidenced by the rapid decrease of test compounds in earthworms after reaching their highest concentrations. The uptake of MNX and TNX increased as exposure concentration increased. Although these earthworms might (anaerobically) degrade RDX to MNX and MNX to TNX, it is hypothesized that this process would be slow. Other biotransformation pathways may be involved in biodegradation of RDX and its N-nitroso metabolites due to the fact that concentrations of tested compounds decreased in both soil and earthworms. It is hoped that these data can be used to refine environmental management strategies for RDX and for performing specific risk assessments of RDX and its N-nitroso metabolites.
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Research Interests: Genetics, Computational Biology, Gene regulation, Molecular Evolution, MicroRNA, and 15 moreBiology, Abiotic Stress, Medicine, Expressed Sequence Tags, Cell, Gene, Clinical Sciences, microRNAs, GenBank, Environmental Stress, Base Sequence, Nucleic Acid Conformation, Nucleotides, Biochemistry and cell biology, and Molecular Sequence Data
An examination of 513 known pre-miRNAs and 237 other RNAs (tRNA, rRNA, and mRNA) revealed that miRNAs were significantly different from other RNAs (p < 0.001). miRNA genes... more
An examination of 513 known pre-miRNAs and 237 other RNAs (tRNA, rRNA, and mRNA) revealed that miRNAs were significantly different from other RNAs (p < 0.001). miRNA genes were less conserved than other RNA genes, although their mature miRNA sequences were highly conserved. The A+U content of pre-miRNAs was higher than non-coding RNA (p < 0.001), but lower than mRNAs. The nucleotides in pre-miRNAs formed more hydrogen bonds and base pairs than in other RNAs. miRNAs had higher negative adjusted minimal folding free energies than other RNAs except tRNAs (p < 0.001). The MFE index (MFEI) was a sufficient criterion to distinguish miRNAs from all coding and non-coding RNAs (p < 0.001). The MFEI for miRNAs was 0.97, significantly higher than tRNAs (0.64), rRNAs (0.59), or mRNAs (0.65). Our findings should facilitate the prediction and identification of new miRNAs using computational and experimental strategies.
Research Interests: Physiology, RNA, Computational Biology, MicroRNA, Biology, and 15 moreMedicine, Non Coding Rna, Gene, Free Energy, ribosomal RNA, Hydrogen Bond, Clinical Sciences, microRNAs, Indexation, Base Sequence, PLANT PROTEINS, Nucleic Acid Conformation, Nucleotides, Biochemistry and cell biology, and Molecular Sequence Data
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Anion exchange membrane (AEM), Nafion® tubing, and strong anion exchange cartridges (SAX) were evaluated as passive sampling devices for perchlorate uptake in soybean (Glycine max). Plant uptake studies and AEM studies were conducted in... more
Anion exchange membrane (AEM), Nafion® tubing, and strong anion exchange cartridges (SAX) were evaluated as passive sampling devices for perchlorate uptake in soybean (Glycine max). Plant uptake studies and AEM studies were conducted in three soil textures: Ottawa sand, silt loam soil, and sandy loam soil. Nafion® tubing and SAX experiments were only conducted in Ottawa sand. AEMs were sampled every hour for the first 12 h, then every 12 h until 72 h. Perchlorate concentrations in plant tissues, SAX, and water solution in Nafion® tubing were determined weekly for 4 weeks. In sand, the amount of perchlorate accumulated in AEM increased linearly with time. Perchlorate uptake by soybean plants was poorly described by linear regressions with perchlorate concentrations on membranes. The only significant relationship between soybean uptake and membrane uptake occurred for data from membranes buried 6–12 h in sand. Significant differences (p < 0.0001) were observed for the amount of perchlorate exchanged on AEM in the three soil textures. There were no differences in perchlorate concentrations in soybean leaves among the three soil textures. Regression analysis of perchlorate concentrations in water within Nafion® tubing and in sand solution indicted that there was a significant linear relationship between them (r 2 = 0.5132, p = 0.0006). Perchlorate was not detected in eluent of SAX. AEM demonstrated its potential to accumulate perchlorate. Nafion® tubing is not a good surrogate for plant uptake, but may be a promising PSD for soil solution. SAX may not be used as a PSD by itself.
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Despite recognition of the lack of reptile ecotoxicology data, the taxon remains poorly studied. Contaminant body burdens are useful in demonstrating exposures to contaminants do occur and may provide insight regarding risks. The purpose... more
Despite recognition of the lack of reptile ecotoxicology data, the taxon remains poorly studied. Contaminant body burdens are useful in demonstrating exposures to contaminants do occur and may provide insight regarding risks. The purpose of this study was to determine organochlorine pesticide burdens in various tissues of terrestrial reptiles opportunistically collected in Arizona. Heptachlor, DDE, and endrin were the most common analytes detected in fat samples. Liver samples contained methoxychlor and heptachlor at greater frequency than other organochlorines. Investigations into chronic low-level exposures are rare for reptiles and research is needed to determine critical body residues associated with adverse impacts.
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Environmental contamination by energetic compounds is an increasing international concern, although little is known of their accumulation in and affect on wildlife. Reptiles are often good models for contaminants studies due to natural... more
Environmental contamination by energetic compounds is an increasing international concern, although little is known of their accumulation in and affect on wildlife. Reptiles are often good models for contaminants studies due to natural history traits that increase their potential for exposure. We report a study to assess accumulation and effects of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, High Melting Explosive) in green anoles (Anolis carolinensis). Acute oral toxicity (LD(50)) was estimated to exceed 2000 mg/kg body weight in adult male and female anoles using a standard up-and-down method. Accumulation of HMX was assessed in adult females via dietary exposure and into eggs by two routes (directly from the soil and via maternal transfer). HMX readily accumulated into adult females in a dose-dependent manner and into eggs following both exposure pathways. However, total HMX in soil-exposed eggs was up to 40-times greater than those exposed via maternal transfer. Although there was a suggestion of an HMX-induced reduction in body weight in adult females, overall there were no effects observed over the 12 week exposure period. The only significant effect on eggs was a 50% reduction in hatching success for eggs exposed to 2000 mg/kg HMX in the soil during incubation. Growth and survival of hatchlings was not affected by HMX exposure. Our results demonstrate that HMX accumulates through the food chain and into eggs from the soil, but likely poses minimal threat to lizards except to hatching success in eggs incubated in soils with HMX levels near maximum environmental concentrations.
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... and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, Texas, 79409-1163, USA 3Current address: 619 Palmetto St., Mount Pleasant, South Carolina, 29464, USA Corresponding author: Thomas Rainwater... more
... and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, Texas, 79409-1163, USA 3Current address: 619 Palmetto St., Mount Pleasant, South Carolina, 29464, USA Corresponding author: Thomas Rainwater (trrainwater@gmail.com ...
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Absorption, distribution, and biotransformation are 3 critical aspects affecting toxicant action in animals. In the present study, B6C3F1 mice (Mus musculus) were exposed for 28 d to contaminated feed that contained 1 of 5 different... more
Absorption, distribution, and biotransformation are 3 critical aspects affecting toxicant action in animals. In the present study, B6C3F1 mice (Mus musculus) were exposed for 28 d to contaminated feed that contained 1 of 5 different hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) concentrations: 0 mg/kg, 0.5 mg/kg, 5 mg/kg, 50 mg/kg, and 500 mg/kg. The authors quantified RDX and its reductive transformation products hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in the stomach, intestine, plasma, liver, and brain of these mice. Average RDX concentrations followed a dose-dependent pattern for all matrices tested. No controls had concentrations above limits of detection. Average RDX concentrations in tissues of exposed mice ranged from 11.1 ng/mL to 182 ng/mL, 25.6 ng/g to 3319 ng/g, 123 ng/g to 233 ng/g, 144 ng/g to 35 900 ng/g, and 51.1 ng/g to 2697 ng/g in the plasma, brain, liver, stomach, and intestine, respectively. A considerable amount of RDX was present in the brain, especially in the highest-exposure group. This is consistent with the widely observed central nervous system effects caused by γ-aminobutyric acid inhibition associated with RDX exposure. N-nitroso metabolites of RDX were also present in tested tissues in a dose-dependent pattern. Average MNX concentrations in the stomachs of mice exposed to RDX ranged from nondetectable in control exposures to 490 ng/g in the highest-exposure groups. In the brain, MNX accumulated at a maximum average concentration of 165.1 ng/g, suggesting the potential formation of MNX from RDX within the brain. At higher exposures, DNX and TNX were present in the stomach, plasma, and brain of mice. The presence of RDX metabolites at notable amounts in different tissues suggests that RDX can transform into its N-nitroso metabolites in vivo by an undefined mechanism.
Research Interests: Chemistry, Medicine, DISTRIBUTION, Biological Sciences, Environmental Sciences, and 14 moreMice, Female, Animals, Absorption, CHEMICAL SCIENCES, Biotransformation, Rodenticides, Distribution, Triazines, Environmental Toxicology and Chemistry, Toxicant, Stomach, Toxicokinetics, and Gamma-Aminobutyric Acid
The effects of carbon fullerenes (C60) on the environment is a growing concern as the use of nanotechnology continues to increase. Previous studies have reported alteration in Daphnia magna behavior, including increased hopping frequency,... more
The effects of carbon fullerenes (C60) on the environment is a growing concern as the use of nanotechnology continues to increase. Previous studies have reported alteration in Daphnia magna behavior, including increased hopping frequency, heart rate, and appendage movement in response to tetrahydrofuran‐solubilized C60 and increased hopping rate and appendage movement in response to tetrahydrofuran‐solubilized C60HxC70Hx exposure. The objective of the current study was to evaluate effects of water‐stirred C60 and sonicated carboxylic acid functionalized fullerenes (fC60) on D. magna behavior. Behavioral endpoints are important because changes in behavior can influence predator avoidance behaviors, alter predation risk, and potentially lead to population‐level effects in D. magna. To evaluate the potential effect of fullerenes on phototactic behavior, D. magna were exposed to 545.4 µg/L C60 and 545.6 µg/L fC60, and vertical position was monitored. Daphnia magna were also exposed to 5...
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Worldwide, access to clean drinking water is not available for more than 800 million people. The biosand filter (BSF), an intermittently operated slow sand filter, was developed to address this problem. The BSF is used in homes to improve... more
Worldwide, access to clean drinking water is not available for more than 800 million people. The biosand filter (BSF), an intermittently operated slow sand filter, was developed to address this problem. The BSF is used in homes to improve water quality. Three main objectives were examined in this research: (1) investigate initial startup and recovery performance after cleaning BSF, (2) examine the number of people the BSF may effectively serve, and (3) determine effects of an extended pause period on BSF performance. Laboratory experiments examined the BSF's ability to reduce fecal coliforms (FC) and turbidity for the various objectives. Results indicate that during the startup period, 27 days were needed to achieve 1 log reduction, while only 17 days were needed after cleaning the BSF to achieve 1 log reduction. A maximum of six people can be effectively served by a single BSF based upon the results of the experiment. A 7-day extended pause period determined that the bacterial ...
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Endocrine disrupting compounds (EDCs) are a contaminant of emerging concern throughout the world, including developing countries where centralized water and wastewater treatment plants are not common. In developing countries, household... more
Endocrine disrupting compounds (EDCs) are a contaminant of emerging concern throughout the world, including developing countries where centralized water and wastewater treatment plants are not common. In developing countries, household scale water treatment technologies such as the biosand filter (BSF) are used to improve drinking water quality. No studies currently exist on the ability of the BSF to remove EDCs. In this experiment, the BSF was evaluated for the removal of three EDCs, estrone (E1), estriol (E3), and 17α-ethinyl estradiol (EE2). Removal results were compared to the slow sand filter (SSF) from the literature, which is similar to the BSF in principal but comparisons have revealed differences in removal of other water quality parameters between SSF and BSF. In general, the BSF minimally removed the compounds from spiked lake water as removal was less than 15% for all three compounds, though mass removal much higher than other studies in which the SSF was used. Household bleach was added to the rate was BSF effluent as suggested in order to achieve different Cl- concentrations (0.67, 2.0, 5.0, and 10.0 mg/L) and subsequent removal of EDCs by oxidation was examined. Concentrations were reduced > 98% for all compounds when the Cl- concentration was greater than 5 mg/L. Removal efficiency was > 50% at the 0.67 mg/L Cl- concentration, while almost 70% removal was observed for all compounds at the 2.0 mg/L Cl- concentration.
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ABSTRACT Natural perchlorate (ClO4-) has been detected in soil, vegetation, food products, and ground and drinking water supplies at various concentrations across the world. For almost a century natural perchlorate has been known to exist... more
ABSTRACT Natural perchlorate (ClO4-) has been detected in soil, vegetation, food products, and ground and drinking water supplies at various concentrations across the world. For almost a century natural perchlorate has been known to exist in Chilean nitrate deposits that are up to 16 million years old, and recent isotopic evidence has confirmed its source to be predominantly atmospheric. Although the source of natural perchlorate has been attributed to atmospheric deposition, there is almost no data available concerning the deposition rate of perchlorate from precipitation. This research effort, supported by SERDP, was designed to investigate the range of concentrations, and temporal and spatial variations in perchlorate deposition. Sub-samples of precipitation collected through the National Atmospheric Deposition program over a two year period were analyzed for perchlorate. Sample locations included 14 continental states, and Puerto Rico. Perchlorate has been detected (DL= 5 ng/L) in over 65 % of all samples tested with a mean value of 12.60 ± 13.60 ng/L and ranged from 0.5) between ClO4- and other ions (Cl-, NO3-, SO4-2, Na+, K+, Ca+2, Mg+2, and NH4+). Results from this study will have important implications to the national perchlorate issue and may aid in explaining the occurrence of non-anthropogenic perchlorate being reported in arid and semi-arid areas.
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Due to the high volume of crude oil released by the Deepwater Horizon oil spill, the salt marshes along the gulf coast were contaminated with crude oil. Biodegradation of crude oil in salt marshes is primarily limited by oxygen... more
Due to the high volume of crude oil released by the Deepwater Horizon oil spill, the salt marshes along the gulf coast were contaminated with crude oil. Biodegradation of crude oil in salt marshes is primarily limited by oxygen availability due to the high organic carbon content of the soil, high flux rate of S(2-), and saturated conditions. Chlorate, nitrate, and perchlorate were evaluated for use as electron acceptors in comparison to oxygen by comparing oil transformation and mineralization in mesocosms consisting of oiled salt marsh sediment from an area impacted by the BP Horizon oil spill. Mineralization rates were determined by measuring CO2 production and δ (13)C of the produced CO2 and compared to transformation evaluated by measuring the alkane/hopane ratios over a 4-month period. Total alkane/hopane ratios decreased (~55-70 %) for all treatments in the following relative order: aerated ≈ chlorate > nitrate > perchlorate. Total CO2 produced was similar between treatm...
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Synthetic musk fragrances (SMFs) are considered micropollutants and can be found in various environmental matrices near wastewater discharge areas. These emerging contaminants are often detected in wastewater at low concentrations; they... more
Synthetic musk fragrances (SMFs) are considered micropollutants and can be found in various environmental matrices near wastewater discharge areas. These emerging contaminants are often detected in wastewater at low concentrations; they are continuously present and constitute a constant exposure source. Objectives of this study were to investigate the environmental fate, transport, and transformation of SMFs. Occurrence of six polycyclic musk compounds (galaxolide, tonalide, celestolide, phantolide, traseolide, cashmeran) and two nitro musk compounds (musk xylene and musk ketone) was monitored in wastewater, various surface waters and their sediments, as well as groundwater, soil cores, and plants from a treated wastewater land application site. Specifically, samples were collected quarterly from (1) a wastewater treatment plant to determine initial concentrations in wastewater effluent, (2) a storage reservoir at a land application site to determine possible photolysis before land application, (3) soil cores to determine the amount of sorption after land application and groundwater recharge to assess lack thereof, (4) a lake system and its sediment to assess degradation, and (5) non-effluent impacted local playa lakes and sediments to assess potential sources of these compounds. All samples were analyzed using gas chromatography coupled with mass spectrometry (GC-MS). Data indicated that occurrence of SMFs in effluent-impacted environments was detectable at ng/L and ng/g concentrations, which decreased during transport throughout wastewater treatment and land application. However, unexpected concentrations, ng/L and ng/g, were also detected in playa lakes not receiving treated effluent. Additionally, soil cores from land application sites had ng/g concentrations, and SMFs were detected in plant samples at trace levels. Galaxolide and tonalide were consistently found in all environments. Information on occurrence is critical to assessing exposure to these potential endocrine disrupting compounds. Such information could provide a scientific framework for establishing the need for environmental regulations.
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Reverse osmosis (RO) is a treatment technology that may be used for the recovery of graywater terrestrially as well as the recovery of wastewater on board long duration, manned space flights. As with terrestrial RO applications,... more
Reverse osmosis (RO) is a treatment technology that may be used for the recovery of graywater terrestrially as well as the recovery of wastewater on board long duration, manned space flights. As with terrestrial RO applications, concentration polarization and membrane fouling lead to decreased productivity and increased energy demands with time. Physiochemical and biological pretreatment options can enhance the performance of the RO system; also, biological pretreatment has the advantages of low energy and consumable requirements as compared to other physiochemical pretreatment options. To determine the degree to which the incorporation of biological treatment enhances RO performance, a series of bench-scale experiments were performed. Observed resistances indicate that biological pretreatment alleviated the degree of non-reversible fouling while also improving the rate of permeate flux in a downstream RO process to further treat water. Results also indicated that enhanced urea hydr...
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Perfluoroalkyl acids (PFAAs) are environmentally persistent components of surfactants that consist of fully fluorinated carbon chains and a terminal sulfonate or carboxylate polar head moiety. Due to their unique amphiphilic properties,... more
Perfluoroalkyl acids (PFAAs) are environmentally persistent components of surfactants that consist of fully fluorinated carbon chains and a terminal sulfonate or carboxylate polar head moiety. Due to their unique amphiphilic properties, PFAAs are used in the manufacturing of products such as aqueous film forming foams (AFFF). There is cause for concern for PFAA contamination resulting from runoff and groundwater infiltration of AFFF that were used during fire training. This study analyzed water and sediment samples that were collected over a 13-month sampling period from bayous upstream and downstream of two former fire training areas located near Barksdale Air Force Base (BAFB); the occurrence and magnitude of PFAAs supported an aquatic ecological risk assessment of potential impacts of PFAAs at the site. Liquid chromatography coupled with mass spectrometry was used for determination of 6 PFAAs listed under the third Unregulated Contaminant Monitoring Rule (UCMR 3). Total PFAA conc...
MicroRNA (miRNA) is one class of newly identified, small, non-coding RNAs that play versatile and important roles in post-transcriptional gene regulation. All miRNAs have similar secondary hairpin structures; many of these are... more
MicroRNA (miRNA) is one class of newly identified, small, non-coding RNAs that play versatile and important roles in post-transcriptional gene regulation. All miRNAs have similar secondary hairpin structures; many of these are evolutionarily conserved. This suggests a powerful approach to predict the existence of new miRNA orthologs or homologs in other species. We developed a comprehensive strategy to identify new miRNA homologs by mining the repository of available ESTs. A total of 481 miRNAs, belonging to 37 miRNA families in 71 different plant species, were identified from more than 6 million EST sequences in plants. The potential targets of the EST-predicted miRNAs were also elucidated from the EST and protein databases, providing additional evidence for the real existence of thesemiRNAs in the given plant species. Some plantmiRNAswere physically clustered together, suggesting that these miRNAs have similar gene expression patterns and are transcribed together as a polycistron,...
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Reptiles have been understudied in ecotoxicology which limits consideration in ecological risk assessments. The goal of this research was threefold: to improve oral and dermal dosing methodologies for reptiles, to generate reptile... more
Reptiles have been understudied in ecotoxicology which limits consideration in ecological risk assessments. The goal of this research was threefold: to improve oral and dermal dosing methodologies for reptiles, to generate reptile toxicity data for pesticides, and to correlate reptile and avian toxicity. We first assessed the toxicity of different dosing vehicles: 100 µL of water, propylene glycol, or acetone were not toxic. We assessed the oral and dermal toxicity of 4 pesticides following the up-and-down procedure. Neither brodifacoum nor chlorothalonil caused mortality at doses < 1750 µg/g. Under the "neat pesticide" oral exposure endosulfan (LD50 = 9.8 µg/g) was more toxic than λ-cyhalothrin (LD50 = 916.5 µg/g). Neither chemical was toxic via dermal exposure. An acetone dosing vehicle increased λ-cyhalothrin toxicity (oral LD50 = 9.8 µg/g, dermal LD50 = 17.5 µg/g), but not endosulfan. Finally, changes in dosing method and husbandry significantly increased dermal λ-c...
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ABSTRACT The possibility of using atmospheric pressure plasma treatment (APT) without any additional functionalizing chemicals as an environmentally friendly technique for processing cotton nonwovens has been investigated. The... more
ABSTRACT The possibility of using atmospheric pressure plasma treatment (APT) without any additional functionalizing chemicals as an environmentally friendly technique for processing cotton nonwovens has been investigated. The quantitative determination of waxes suggested that APT results in the removal of waxes from cotton nonwovens and consequently increases its hydrophilicity. Fourier transform infrared studies showed that APT was capable of removing wax covering individual layers of cotton fibers. Intense plasma treatment causes a decrease in the strength of cotton nonwovens. Results show that APT can be a viable alternative for caustic soda treatment for dewaxing cotton.
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Perchlorate has been known to be present in salt deposits from the Atacama Desert for over a century. Its presence is typically associated with NO3-, although relatively few samples from the Atacama have been evaluated. Perchlorate in the... more
Perchlorate has been known to be present in salt deposits from the Atacama Desert for over a century. Its presence is typically associated with NO3-, although relatively few samples from the Atacama have been evaluated. Perchlorate in the Atacama nitrate deposits has a substantial Delta17O anomaly strongly suggesting an atmospheric origin, or at least a production mechanism involving O3 (e.g. surface oxidation). Reports of natural ClO4- in North America have been increasing recently. These reports indicate that ClO4- is widely distributed in groundwater and in unsaturated surface soils. However, most reported occurrences have been at low concentrations. Because of the association of ClO4- with NO3- in the Atacama deposits, previously identified NO3- deposits with atmospheric components in North America were investigated for the occurrence of ClO4-. These nitrate deposits are located in the Death Valley region of the Mojave Dessert and have been previously characterized with respect ...
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Research Interests: Environmental Science, Arsenic, Medicine, Multidisciplinary, New Orleans, and 15 moreEnvironmental science and technology, Soil Pollution, Sampling, Disasters, Flood, Hurricane Katrina, Lead, Follow-up studies, Sediments, Louisiana, Sediment, Metals, Trace element, Geologic Sediments, and Soil Pollutants
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Neonicotinoids are a leading class of insecticides on the global market, accounting for nearly 25%. They are widely used in both agricultural and residential settings. Causing neuron failure by irreversibly binding to the insect nicotinic... more
Neonicotinoids are a leading class of insecticides on the global market, accounting for nearly 25%. They are widely used in both agricultural and residential settings. Causing neuron failure by irreversibly binding to the insect nicotinic acetylcholine receptor, neonicotinoids offer broad spectrum efficacy against a variety of pests. However, because they are non-selective with regard to insect species, there has been some concern with neonicotinoid use over threats to pollinators such as honeybees, and potential indirect effects to migratory waterfowl as a result of invertebrate prey population depletion. In order to study occurrence and fate of neonicotinoids (thiamethoxam and imidacloprid), we analyzed cotton leaves on plants grown from neonicotinoid-treated seeds and corresponding soil samples between cotton rows. Neonicotinoid concentration data from cotton leaves appears to be consistent with the claim that seed treatments protect plants for 3–4 weeks; by 30 days post-planting...