Publications by authors named "Francis X M Casey"

Although livestock manure, such as from swine (Sus scrofa domestica), have high capacity to introduce endocrine-disrupting free estrogens into the environment, the frequency of estrogen detections from reconnaissance studies suggest that these compounds are ubiquitous in the environment, perhaps resulting from historic manure inputs (e.g. cattle grazing residues, undocumented historic manure applications) or uncontrolled natural sources.

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Contaminated soils pose a risk to human and ecological health, and thermal remediation is an efficient and reliable way to reduce soil contaminant concentration in a range of situations. A primary benefit of thermal treatment is the speed at which remediation can occur, allowing the return of treated soils to a desired land use as quickly as possible. However, this treatment also alters many soil properties that affect the capacity of the soil to function.

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17β-Estradiol (E2), a natural, endocrine-disrupting, steroid hormone, is excreted by all vertebrates and can enter the environment from domestic animal and wildlife wastes. Multiple field studies using livestock manures as E2 sources suggest significant background concentrations of E2 (e.g.

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Successful remediation of oil-contaminated agricultural land may include the goal of returning the land to prespill levels of agricultural productivity. This productivity may be measured by crop yield, quality, and safety, all of which are influenced by soil characteristics. This research was conducted to determine if these metrics are affected in hard red spring wheat ( L.

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Given the recent increase in crude oil production in regions with predominantly agricultural economies, the determination of methods that remediate oil contamination and allow for the land to return to crop production is increasingly relevant. Ex situ thermal desorption (TD) is a technique used to remediate crude oil pollution that allows for reuse of treated soil, but the properties of that treated soil are unknown. The objectives of this research were to characterize TD-treated soil and to describe implications in using TD to remediate agricultural soil.

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The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter (OM). Sampling of the liquid layer for 14days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4hr, and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336hr.

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The fate of [C]17β-estradiol ([C]E2) was monitored for 42 d in triplicate 10-L anaerobic digesters. Total radioactive residues decreased rapidly in the liquid layer of the digesters and reached a steady-state value of 22 to 26% of the initial dose after 5 d. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analyses of the liquid layer of the anaerobic digesters indicated a rapid degradation of E2 to estrone (E1), which readily adsorbed to the sludge layer subsequent to its formation.

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Animal manure is the primary source of exogenous free estrogens in the environment, which are known endocrine-disrupting chemicals to disorder the reproduction system of organisms. Conjugated estrogens can act as precursors to free estrogens, which may increase the total estrogenicity in the environment. In this study, a comprehensive model was used to simultaneously simulate the coupled sorption and transformation of a sulfate estrogen conjugate, 17β-estradiol-17-sulfate (E2-17S), in various soil-water systems (non-sterile/sterile; topsoil/subsoil).

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The dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the environmental fate and transport of steroidal estrogens. The first objective of this study was to quantify the association of 17β-estradiol (E2) with the DF and CF isolated from (i) liquid swine manure (LSM), (ii) a soil:water mixture (soil), and (iii) a LSM:soil:water mixture (Soil+LSM). The appropriate CF and DF size fractions of the Soil, Soil+LSM, and LSM media were obtained by first filtering through a 0.

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To identify abiotic processes that govern the fate of a sulfate conjugated estrogen, 17β-estradiol-17-sulfate (E2-17S), soil batch experiments were conducted to investigate the dissipation, sorption, and degradation of radiolabeled E2-17S under sterilized conditions. The aqueous dissipation half-lives (DT50) for E2-17S ranged from 2.5 to 9.

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In the environment, estrogen conjugates can be precursors to the endocrine-disrupting free estrogens, 17β-estradiol (E2) and estrone (E1). Compared to other estrogen conjugates, 17β-estradiol-17-sulfate (E2-17S) is detected at relatively high concentrations and frequencies in animal manure and surface runoff from fields receiving manure. To elucidate the lifecycle of manure-borne estrogens and their conjugates in the environment, the fate of radiolabelled E2-17S in agricultural soils was investigated using laboratory batch studies with soils of different organic carbon (OC) content (1.

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Estrogens, a potent group of endocrine disruptors toward aquatic species, are primarily excreted as conjugates from humans and animals. Radioassay-based approaches with detailed speciation have been frequently conducted for environmental-fate studies for pesticides; however, such techniques have not been exploited for reproductive hormones, and especially for hormone conjugates. This article describes a simple, robust, and high-mass-recovery approach to investigate the fate and transformation of a prototype estrogen conjugate, that is, 17β-estradiol-3-glucuronide (E2-3G), and its metabolites (free estrogens) in a laboratory soil and water matrix without the need for enzymatic cleavage and/or fluorescent derivatization.

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In the environment, conjugated estrogens are nontoxic but may hydrolyze to their potent unconjugated, 'free' forms. Compared to free estrogens, conjugated estrogens would be more mobile in the environment because of their higher water solubility. To identify the fate of a conjugated estrogen in natural agricultural soils, batch experiments were conducted with a (14)C labeled prototype conjugate, 17β-estradiol-3-glucuronide (E2-3G).

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It is important to understand the link between land surface/soil properties and shallow groundwater quality. To that end, soil properties and near-water-table groundwater chemistry of a shallow, unconfined aquifer were measured on a 100-m grid on a 64-ha irrigated field in southeastern North Dakota. Soil properties and hydrochemistry were compared via multivariate analysis that included product-moment correlations and factor analysis/principal component analysis.

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The occurrence of the manure-borne estrogen, 17β-estradiol (E2), was investigated in laboratory and field soils. In the laboratory, E2 was applied to soil to simulate concentrations found in swine (Sus scrofa domestica) manure (5000ngL(-1)). The aqueous-extracted E2 dissipated in the soil by 98% within 1h and was not significantly different from background concentrations (18ng L(-1)) for the duration of the experiment (64h).

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17β-estradiol (E2) is a natural estrogenic hormone found in animal manure and urine, which may cause endocrine disruption in sensitive organisms. 17β-Estradiol has been widely detected in the environment, and animal agriculture may be an important source. The objectives of this study were to investigate the potential sources and/or spatial and temporal characteristics contributing to detections of E2 at the farm-scale.

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An analytical method was developed using ultra-high-pressure liquid chromatography-triple quadrupole-tandem mass spectrometry (UHPLC-TQ-MS/MS) to simultaneously analyze 14 sulfonamides (SA) in 6 min. Despite the rapidity of the assay the system was properly re-equilibrated in this time. No carryover was observed even after high analyte concentrations.

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The hormone 17beta-estradiol (E2) can cause endocrine disruption in sensitive species at part per trillion concentrations. The persistence and transport pathways of manure-borne E2 in agricultural soils were determined by comparing its occurrence with the transfer of water and the transport of non-sorbing fluorobenzoic acid (FBA) tracers. This comparison was done using capillary wick lysimeters installed 0.

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A feasibility study of phosphorylated-polyvinyl alcohol immobilized and free mixed bacterial culture bioaugmentation for removing atrazine in agricultural infiltrate was conducted utilizing a sand column setup. The effects of bacterial cell loading and infiltration rate on atrazine degradation were investigated by short-term tests in which the amount of synthetic infiltrate fed through was five times of the void volume (five pore volumes) of the sand column. In addition, the loss of the inoculated atrazine-degrading cultures and the change of bacterial community were determined.

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Bench-scale sand column breakthrough experiments were conducted to examine atrazine remediation in agricultural infiltrate by Agrobacterium radiobacter J14a (J14a) immobilized in phosphorylated-polyvinyl alcohol compared to free J14a cells. The effects of cell loading and infiltration rate on atrazine degradation and the loss of J14a were investigated. Four sets of experiments, i) tracers, ii) immobilized dead cells, iii) immobilized cells, and iv) free cells, were performed.

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Bench-scale sand column breakthrough experiments were conducted to examine atrazine removal in agricultural infiltrate by Agrobacterium radiobacter J14a (J14a) immobilized in phosphorylated-polyvinyl alcohol compared to free J14a cells. The effects of cell loading and infiltration rate on atrazine degradation and the loss of J14a were investigated. Four sets of experiments, (i) tracers, (ii) immobilized dead cells, (iii) immobilized cells, and (iv) free cells, were performed.

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Testosterone is an endocrine disruptor that is released into the environment from natural and anthropogenic sources. The objective of this study was to achieve a better understanding of the complex fate and transport of this labile compound in an undisturbed agricultural soil (a Hamar Sandy, mixed, frigid typic Endoaquolls). This was done by using batch and miscible-displacement experiments, and by using a chemical nonequilibrium transport model.

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Steroidal hormones are constantly released into the environment by man-made and natural sources. The goal of this study was to examine the persistence and fate of 17beta-estradiol and testosterone, the two primary natural sex hormones. Incubation experiments were conducted under aerobic and anaerobic conditions using [4-(14)C]-radiolabeled 17beta-estradiol and testosterone.

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The most toxic dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD), and obtaining comprehensive experimental data for this compound is challenging. However, several nontoxic isomers of 2378-TCDD exist, and can provide significant experimental evidence about this highly toxic dioxin. The goal of this study was to obtain experimental evidence for the fate and transport of 2378-TCDD in natural soils using its nontoxic isomers, 1,2,7,8-tetrachlorodibenzo-p-dioxin (1278-TCDD), 1,3,7,8-tetrachlorodibenzo-p-dioxin (1378-TCDD), and 1,4,7,8-tetrachlorodibenzo-p-dioxin (1478-TCDD).

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Potent estrogenic hormones are consistently detected in the environment at low concentration, yet these chemicals are strongly sorbed to soil and are labile. The objective of this research was to improve the understanding of the processes of sorption, mobility, and transformation for estrogens in natural soils, and their interaction. Equilibrium and kinetic batch sorption experiments, and a long-term column study were used to study the fate and transport of 17beta-estradiol and its primary metabolite, estrone, in natural soil.

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