bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of the solid uranium(VI) dioxo-diacetohydroxamate complex
Authors: Gong Cynthia-May S. , Poineau Frédéric , Czerwinski Kenneth R. 
Published: July 2007

A novel dry synthesis for the uranium(VI) dioxo-diacetohydroxamate (UAHA) complex has been developed. The complex was generated in >80% yield by mechanically grinding solid uranyl acetate dihydrate (UAc) with solid acetohydroxamic acid in stoichiometric amounts. The resulting UO2(AHA)2·4H2O solid is purified by washing with acetone. The stoichiometry was confirmedviacolorimetric assays for U(VI) and AHA. The analogous ferric trisacetohydroxamate complex (FeAHA) was synthesized for comparison. A novel dry synthesis for the uranium(VI) dioxo-diacetohydroxamate (UAHA) complex has been developed. The complex was generated in >80% yield by mechanically grinding solid uranyl acetate dihydrate (UAc) with solid acetohydroxamic acid in stoichiometric amounts. The resulting UO2(AHA)2·4H2O solid is purified by washing with acetone. The stoichiometry was confirmedviacolorimetric assays for U(VI) and AHA. The analogous ferric trisacetohydroxamate complex (FeAHA) was synthesized for comparison.The UAHA solid was extensively characterized by ultraviolet-visible (UV-vis), Fourier-transform infrared (FT-IR), and extended X-ray absorption fine structure (EXAFS) spectroscopies. The compound did not fluoresce after laser excitation. Proton nuclear magnetic resonance (NMR) spectra were obtained of the complex in D2O, acidified acetonitrile-d3, and DMSO-d6. The solubility was determined over a range of solvents. It was determined that in the purified solid, two bidentate AHA molecules bind to uranylviathe carbonyl and hydroxamate oxygen atoms, a structure analogous to known ferric, nickel, and lanthanum AHA complexes. In an acidic environment, binding is monodentate through the hydroxamate oxygen. And in aqueous solution, the UAHA complex assumes both binding moieties, depending on the pH. This pH-dependent speciation change is demonstrated for the first time.The easy synthesis and purification of UAHA enables researchers to strictly control reaction conditions; to eliminate interfering salts and water; and to study the complex in the solid-phase.
Long-term sediment bioassay of lead toxicity in two generations of the marine amphipodElasmopus laevis, S.I. Smith, 1873
Authors: Ringenary Mark J. , Molof Alan H. , Tanacredi John T. , Schreibman Martin P. , Kostarelos Konstantinos 
Published: July 2007

AbstractSediments are evaluated for toxicity by measuring mortality in a single cohort of amphipods in either acute (10-d) or chronic (28-d) bioassays. This investigation differed from conventional bioassays in four ways: Sublethal effects (fecundity) were estimated; the testing period was 60+ d; two successive generations were examined; and Elasmopus laevis Smith, 1873, amphipods were employed. Four test sediments were created between 58 and 424 μg/g of lead using the 30-μg/g whole-sediment as the control. Bioaccumulated lead at 60 d varied as a linear function of lead concentration in the sediments. Fecundity, as estimated by offspringper-chamber and/or percent reproductive success, was reduced as sediment lead concentrations increased and reproduction was delayed compared with the control. The reduction in offspring production per test chamber varied significantly as an inverse function of lead sediment concentration, best described by a curvilinear exponential equation. It was concluded that E. laevis exposed to 118 μg/g and higher could not maintain a population as large as that in the control. Although the current sediment quality guideline for lead stipulates that adverse biological effects likely will occur above 218 μg/g, this study revealed a statistically significant negative reproductive response at 118 μg/g lead, and suggests that the current regulatory guideline for lead, based on lethality, should be reconsidered.
Toxicity of cadmium to early life stages of brown trout (Salmo trutta) at multiple water hardnesses
Authors: Brinkman Stephen F. , Hansen Daria L. 
Published: July 2007

AbstractToxicity of cadmium to early life stages of brown trout (Salmo trutta) was determined at multiple water hardnesses. Increasing water hardness decreased cadmium toxicity. Postswimup fry were much more sensitive than embryos and larvae. Chronic values from early life stage tests initiated with eyed embryos were 3.52, 6.36, and 13.6 μg Cd/L at water hardnesses of 30.6, 71.3, and 149 mg/L, respectively. In tests initiated with 30-d postswimup fry, chronic values were 1.02, 1.83, and 6.54 μg Cd/L at water hardnesses of 29.2, 67.6, and 151 mg/L, respectively. Higher chronic values from the early life stage tests compared to tests initiated with swimup fry likely are caused by acclimation during cadmium-tolerant embryo and larval stages. Growth was not affected by cadmium in the early life stage tests but was negatively affected in tests initiated with fry at water hardnesses of 29.2 and 67.6 mg/L. Concentrations of cadmium that reduced growth were higher than those that increased mortality. Median lethal concentrations for swimup fry after 96 h were 1.23, 3.90, and 10.1 μg Cd/L at water hardnesses of 29.2, 67.6, and 151 mg/L, respectively. Test results enable prediction of acute mortality of brown trout swimup fry based on cadmium concentration and water hardness.
Decreased toxicity to terrestrial plants associated with a mixture of methyltert-butyl ether and its metabolitetert-butyl alcohol
Authors: An Youn-Joo , Lee Woo-Mi 
Published: July 2007

AbstractThe influence of the main fuel oxygenate methyl tert-butyl ether (MTBE) and its key metabolite, tert-butyl alcohol (TBA), on the growth of a plant seedling was studied separately and in combination. The test plants were mung bean (Phaseolus radiatus), cucumber (Cucumis sativus), wheat (Triticum aestivum), sorghum (Sorghum bicolor), kale (Brassica alboglabra), Chinese cabbage (Brassica campestris), and sweet corn (Zea mays). The growth of all the plants was adversely affected by TBA and MTBE. The 5-d median effective concentration (EC50) for the plants exposed to MTBE and TBA were in the range of 680 to 1,000 mg MTBE/kg soil (dry wt) and 1,200 to 3,500 mg TBA/kg soil (dry wt), respectively. The relative order of the sensitivity rankings is almost the same for MTBE and TBA. Methyl tert-butyl ether is more toxic than TBA to most of the test species. Based on the EC50 values, MTBE is approximately 1.5 to 3 times more potent than TBA. The sum of the toxic unit (TU) at 50% inhibition of the mixture (EC50mix) was calculated from the dose (TU-based)-response relationships using the trimmed Spearman-Karber method. The combined effect of MTBE + TBA on the plant growth was less than additive because the EC50mix values were greater than 1 TU. This phenomenon may be due to the competition of MTBE and TBA in terms of their intake by plants. The combined effects of MTBE and TBA should be taken into account to assess their risk in gasoline-contaminated sites.
Interactions of silver, cadmium, and copper accumulation in green mussels (Perna viridis)
Authors: Ng Tania Y.-T. , Wang Wen-Xiong 
Published: July 2007

Abstract
Metal interaction is vital for assessing the use of aquatic organisms in monitoring metal contamination. The present study examined the interactions between Ag and Cd accumulation and between Ag and Cu accumulation in the green mussel (Perna viridis). Accumulation of Ag and Cd in the whole tissue of green mussels exposed to 5 μg/L of Ag and 20 μg/L of Cd for two weeks was independent; however, interaction was observed at the subcellular level. Approximately 25% of Ag shifted from the insoluble fraction (IF) to the metallothionein-like protein in the presence of Cd, which probably resulted from the competition of Cd on IF in the Ag-Cd coexposure. On the other hand, coexposure of the mussels to Ag (5 μg/L) and Cu (30 μg/L) for two weeks increased the Ag and Cu concentrations in the tissue synergistically (two- to fivefold), but Ag and Cu subcellular distributions were similar in the coexposed and the singly exposed mussels. Exposure to Ag alone increased the dietary uptake of Ag by 30%, but the effect was reduced in the presence of Cd. No interaction, however, was observed between uptake rates of metals from the dissolved phase. To conclude, a significant interaction was observed for total Ag and Cu accumulation, but not for total Ag and Cd accumulation, in the mussels. Metal interaction is more likely to be observed at the subcellular level than at the whole-tissue level.
Wastewater treatment plants as a pathway for aquatic contamination by pharmaceuticals in the Ebro river basin (Northeast Spain)
Authors: Gros Meritxell , Petrović Mira , Barceló Damià 
Published: July 2007

Abstract
The occurrence of 28 pharmaceuticals of major human consumption in Spain, including analgesics and anti-inflam-matories, lipid regulators, psychiatric drugs, antibiotics, antihistamines, and β-blockers, was assessed along the Ebro river basin, one of the biggest irrigated lands in that country. Target compounds were simultaneously analyzed by off-line solid-phase extraction, followed by liquid chromatography-tandem mass spectrometry. The loads of detected pharmaceuticals and their removal rates were studied in seven wastewater treatment plants (WWTPs) located in the main cities along the basin. Total loads ranged from 2 to 5 and from 0.5 to 1.5 g/d/1,000 inhabitants in influent and effluent wastewaters, respectively. High removal rates (60–90%) were achieved mainly for analgesics and anti-inflammatories. The other groups showed lower rates, ranging from 20 to 60%, and in most cases, the antiepileptic carbamazepine, macrolide antibiotics, and trimethoprim were not eliminated at all. Finally, the contribution of WWTP effluents to the presence of pharmaceuticals in receiving river waters was surveyed. In receiving surface water, the most ubiquitous compounds were the analgesics and anti-inflammatories ibuprofen, diclofenac, and naproxen; the lipid regulators bezafibrate and gemfibrozil; the antibiotics erythromycin, azithromycin, sulfamethoxazole, trimethoprim, and less frequently, ofloxacin; the antiepileptic carbamazepine; the antihistamine ranitidine; and the β-blockers atenolol and sotalol. Although levels found in WWTP effluents ranged from low μg/L to high ng/L, pharmaceuticals in river waters occurred at levels at least one order of magnitude lower (low ng/L range) because of dilution effect. From the results obtained, it was proved that WWTP are hot spots of aquatic contamination concerning pharmaceuticals of human consumption.
Analysis of glutathione endpoints for measuring copper stress in Chlamydomonas reinhardth
Authors: Stoiber Tasha L. , Shafer Martin M. , Perkins Dawn A. Karner , Hemming Jocelyn D.C. , Armstrong David E. 
Published: July 2007

Abstract
Glutathione (GSH) is the most abundant nonprotein thiol in eukaryotic cells and it protects cells by functioning as an antioxidant and a metal-binding ligand. Because glutathione readily undergoes oxidation-reduction reactions to combat oxidative stress, intracellular ratios of the reduced (GSH) to the oxidized (GSSG) forms of glutathione may serve as an important biomarker of exposure and effect of trace metals in eukaryotic cells. We compared sensitivity of glutathione ratios in the freshwater alga Chlamydomonas reinhardtii to the traditional endpoints of cell growth rates and chlorophyll a following exposure to Cu for periods of 6 and 24 h. A response of the GSH:GSSG ratio to Cu concentration was observed at Cu levels of 40 and 80 nM after exposure for both 6 and 24 h. The concentration of total GSH at 24 h was roughly half the value at 6 h after exposure to either 40 or 80 nM Cu. A response for cell growth rate was observed only at 24 h, whereby the average specific growth rate decreased from about 1.1 to 0.4 d−1. The total Cu concentrations eliciting a cell response of 50%, effect concentrations (EC50s), after 24 h of exposure were similar (49.2, 49.8, and 38.2 nM Cu) and not significantly different for GSH:GSSG ratio, GSH levels, and specific growth, respectively. Total cell-associated Cu concentrations after exposure for 24 h were calculated from the EC50 endpoints and ranged from 13.3 to 17.0 fg/cell. Overall, thiol ratios were indicative of toxicity resulting from exposure to Cu, but precision may be greater for the cell growth rate endpoints.
Influence of the temperature gradient in blubber on the bioaccumulation of persistent lipophilic organic chemicals in seals
Authors: Czub Gertje , McLachlan Michael S. 
Published: July 2007

Abstract
Seals constitute an important link in food webs of the Arctic environment and are an important vector of persistent lipophilic organic pollutants to top predators (e.g., polar bears) and humans. Two fugacity-based, non-steady state, mechanistic lifetime models were assembled to explore the influence of the temperature gradient in the insulating blubber on the distribution and bioaccumulation of persistent lipophilic organic pollutants in seals. The behavior of a two-compartment model that distinguishes between the gastrointestinal tract and the seal itself was compared with a three-compartment model, in which a separate blubber compartment was implemented with a temperature gradient through the insulation layer. In both models, equilibrium partitioning between the animal's tissues, blood, and milk was assumed. The models were parameterized for ringed seals (Phoca hispida) and evaluated using field data for bioaccumulation of polychlorinated biphenyls in this species. The two-compartment model resulted in predicted concentrations below reported field data. This was in particular the case for females, for which the elimination of the contaminants via milk was overpredicted by up to one order of magnitude. The three-compartment model with its consideration of the temperature gradient in blubber yielded predictions that were much more consistent with the field data. It also predicted a fractionation of polychlorinated biphenyl congeners between different blubber layers, as well as between blubber and blood or milk, which was in good qualitative agreement with observations reported in the literature. This work indicates that the temperature gradient in the blubber has an impact on the bioaccumulation of persistent lipophilic organic pollutants in seals and in marine mammals in general.
Bioavailability and microbial adaptation to elevated levels of uranium in an acid, organic topsoil forming on an old mine spoil
Authors: Joner Erik Jautris , Munier-Lamy Colette , Gouget Barbara 
Published: July 2007

Abstract
An old mine spoil at a 19th-century mining site with considerable residues of uranium (400–800 mg U/kg) was investigated with respect to U concentrations in soil and plants and tolerance to U in the soil microbial community in order to describe the bioavailability of U. Measurements of soil fractions representing water-soluble U, easily exchangeable U, and U bound to humified organic matter showed that all fractions contained elevated concentrations of U. Plant U concentrations were only 10 times higher at the mine spoil site compared to the reference site (3 mg U/kg vs 0.3 mg U/kg), while the most easily available soil fractions contained 0.18 to 0.86 mg U/kg soil at the mine spoil. An ecotoxicity bioassay using incorporation of [3H]thymidine into the indigenous microbial communities of the two soils in the presence of increasing U concentrations showed that microorganisms at the mining site were sensitive to U but also that they had acquired a substantial tolerance toward U (EC50, the effective concentration reducing activity by 50% of UO2-citrate was ≈ 120 μM as compared to 30 μM in the reference soil). In the assay, more than 40% of the microbial activity was maintained in the presence of 1 μM UO2-citrate versus 3% in the reference soil. We conclude that U-enriched mining waste can contain sufficiently elevated concentrations of bioavailable U to affect indigenous microorganisms and that bioavailable U imposes a selection pressure that favors the development of a highly uranium-tolerant microbial community, while plant uptake of U remains low.
Dynamic energy budget as a basis to model population-level effects of zinc-spiked sediments in the gastropodValvata piscinalis
Authors: Ducrot Virginie , Péry Alexandre R.R. , Mons Raphaël , Quéau Hervé , Charles Sandrine , Garric Jeanne 
Published: July 2007

AbstractThis paper presents original toxicity test designs and mathematical models that may be used to assess the deleterious effects of toxicants on Valvata piscinalis (Mollusca, Gastropoda). Results obtained for zinc, used as a reference toxicant, are presented. The feeding behavior, juvenile survival, growth, age at puberty, onset of reproduction, number of breedings during the life cycle, and fecundity were significantly altered when the snails were exposed to zinc-spiked sediments. Dynamic energy budget models (DEBtox) adequately predicted the effects of zinc on the V. piscinalis life cycle. They also provided estimates for life-cycle parameters that were used to parameterize a demographic model, based on a Z-transformed life-cycle graph. The effect threshold for the population growth rate (γ) was estimated at 259 mg/kg dry sediment of zinc, showing that significant changes in abundance may occur at environmental concentrations. Significant effects occurring just above this threshold value were mainly caused by the severe impairment of reproductive endpoints. Sensitivity analysis showed that the value of γ depended mainly on the juvenile survival rate. The impairment of this latter parameter may result in extinction of V. piscinalis. Finally, the present study highlights advantages of the proposed modeling approach in V. piscinalis and possible transfer to other test species and contaminants.
Application of a source apportionment model in consideration of volatile organic compounds in an urban stream
Authors: Asher William E. , Luo Wentai , Campo Kimberly W. , Bender David A. , Robinson Keith W. , Zogorski John S. , Pankow James F. 
Published: July 2007

Abstract
Position-dependent concentrations of trichloroethylene and methyl-tert-butyl ether are considered for a 2.81-km section of the Aberjona River in Massachusetts, USA. This river flows through Woburn and Winchester (Massachusetts, USA), an area that is highly urbanized, has a long history of industrial activities dating to the early 1800s, and has gained national attention because of contamination from chlorinated solvent compounds in Woburn wells G and H. The river study section is in Winchester and begins approximately five stream kilometers downstream from the Woburn wells superfund site. Approximately 300 toxic release sites are documented in the watershed upstream from the terminus of the study section. The inflow to the river study section is considered one source of contamination. Other sources are the atmosphere, a tributary flow, and groundwater flows entering the river; the latter are categorized according to stream zone (1, 2, 3, etc.). Loss processes considered include outflows to groundwater and water-to-atmosphere transfer of volatile compounds. For both trichloroethylene and methyl-tert-butyl ether, degradation is neglected over the timescale of interest. Source apportionment fractions with assigned values αinflow, α1, α2, α3, etc. are tracked by a source apportionment model. The strengths of the groundwater and tributary sources serve as fitting parameters when minimizing a reduced least squares statistic between water concentrations measured during a synoptic study in July 2001 versus predictions from the model. The model fits provide strong evidence of substantial unknown groundwater sources of trichloroethylene and methyl-tert-butyl ether amounting to tens of grams per day of trichloroethylene and methyl-tert-butyl ether in the river along the study section. Modeling in a source apportionment manner can be useful to water quality managers allocating limited resources for remediation and source control.
Aquatic invertebrate resting egg sensitivity to glutaraldehyde and sodium hypochlorite
Authors: Raikow David F. , Landrum Peter F. , Reid David F. 
Published: July 2007

Abstract
Ballast tank treatment technologies are currently in development to reduce the risk of acquiring or transporting viable aquatic organisms that could be introduced to ecosystems and become invasive. Aquatic invertebrate resting eggs represent a challenge to such technologies because of morphological and biochemical adaptations to stress that also protect eggs from artificial stressors. To evaluate the potential efficacy of chemical biocides for ballast tank treatment, the present study examined the acute toxicity of glutaraldehyde and sodium hypochlorite on resting eggs of the freshwater cladoceran Daphnia mendotae and marine brine shrimp (Artemia sp.). Glutaraldehyde was toxic to resting eggs of Artemia sp., as indicated by a lethal concentration to 90% of organisms (LC90) of 95% confidence interval (226 ± 10 mg/L). Daphnia mendotae, in contrast, displayed erratic responses to glutaraldehyde. Sodium hypochlorite was similarly toxic to resting eggs of Artemia sp. and D. mendotae, which displayed LC90s of 86.5 ± 3.0 and 78.3 ± 1.6 mg/L, respectively. Burial in sediment protected resting eggs from toxicants. The present results corroborate those from previous investigations of resting egg sensitivity to artificial stressors, supporting the conclusions that resting eggs are less sensitive than other life stages to artificial stressors and that chemical biocide concentrations effective against other life stages may be ineffective against resting stages.
Sorption of tylosin A, D, and A-aldol and degradation of tylosin a in soils
Authors: Sassman Stephen A. , Sarmah Ajtt K. , Lee Linda S. 
Published: July 2007

Abstract
Heightened concerns regarding the potential impact on soil and water quality of veterinary antibiotics warrant a better understanding of the environmental fate of antibiotics in soil. Sorption of the macrolides tylosin A (TA), tylosin D, and TA-aldol was measured in several soils and evaluated with respect to soil pH, organic matter content, percentage clay, and cation-exchange capacity (CEC). Tylosin and related compounds exhibit similar sorption characteristics and generally are strongly sorbed, with sorption being well and positively correlated to surface area, clay content, and CEC. Sorption coefficients normalized by CEC were within a narrow range (104.1±0.21 L/molc) for all but one soil; however, good extraction recoveries with only methanol for most soils suggested that hydrophobic processes also contribute to sorption. Aerobic degradation of TA over a three-month period in two freshly collected agricultural soils and 60Co-irradiated soils indicated that both abiotic and microbial processes contribute to TA transformation. The abiotic process was much slower and dominated in the first two weeks, followed by rapid microbial degradation within 3 d. Three primary degradation products were identified using liquid chromatography with full-scan mass spectrometry, with unconfirmed identifications of TA having the aldehyde group oxidized to an acid (m/z = 932) in both soils and tyslosin B (m/z = 772) as well as tylosin B having the aldehyde group oxidized to an acid (m/z = 788) in the sandy soil.
Cognitive Pathology and Moral Judgment in Managers
Authors: Curlo Eleonora , Strudler Alan 
Published: July 2007

Abstract:We examine the moral and managerial significance of some empirical studies in cognitive psychology. We suggest that these results may plausibly be interpreted as expressing deontological commitments of experimental subjects, even though psychologists who discuss the results seem to suppose that they show that people are irrational consequentialists. We argue that the plausibility of our interpretation suggests how managers who wish to take seriously entrenched social views on morality might best craft corporate policy on corporate responsibility, and we suggest that the form of argument we employ may be regarded as a kind of appeal to reflective equilibrium.