bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of sorption on benzene biodegradation in sandy soil
Authors: Kim Song-Bae , Hwang In , Kim Dong-Ju , Lee Sangjin , Jury William A. 
Published: November 2004

Abstract
The effect of sorption on benzene biodegradation in sandy soil was studied by conducting kinetic microcosm batch tests in soil-free solution and in the presence or absence of bacteria in soil materials with varying degrees of powdered activated carbon (PAC). In the soil-free experiment, benzene was added to a solution inoculated with Pseudomonas aeruginosa bacteria in order to achieve a potential or maximum biodegradation rate. In subsequent experiments, benzene was applied to a solution containing sandy soil and various PAC contents with and without inoculating P. aeruginosa. Benzene concentrations in the soil-free experiments decreased with time with two characteristic rates. A two-stage exponential decay model adequately represented the observed solution concentration pattern with time. Sorption experiments in bacteria-free soil also decreased monotonically, with the extent of sorption increasing as PAC content increased. The sorption data were represented well with a two-stage irreversible sorption model. A third set of experiments in the presence of both soil and bacteria showed more rapid concentration loss from solution than the set of experiments with bacteria-free soil. A model combining sorption and degradation greatly overestimated the loss when the rate coefficient from the bacteria-free experiments was used. Satisfactory agreement between model predictions and observed values was obtained when the degradation rate coefficients were decreased by factors ranging from 3 to 10, depending on the amount of PAC present. Model predictions of the percentage benzene mass remaining in the soil after 25 d of degradation ranged from 72 to 97%, depending on the PAC content, compared to only 2.5% remaining in soil-free solution.
Inherited resistance to arsenate toxicity in two populations of Lumbricus rubellus
Authors: Langdon Caroline J. , Piearce Trevor G. , Meharg Andrew A. , Emple Kirk T. S 
Published: November 2004

Abstract
No unequivocal evidence exists of genetically inherited resistance to metals/metalloids in field populations of earthworms. We studied cocoon production in adult Lumbricus rubellus Hoffmeister collected from an abandoned arsenic and copper mine (Devon Great Consols, Devon, UK), and abandoned tungsten mine (Carrock Fell, Cumbria, UK) and an uncontaminated cultured population. The earthworms were kept in uncontaminated soil for nine weeks. From a total of 42 L. rubellus from each site, Devon Great Consols adults produced 301 cocoons, of which 42 were viable; Carrock Fell 60 cocoons, of which 11 were viable; and the reference population 101 cocoons, of which 62 were viable. The hatchlings were collected and stored at 4°C at weekly intervals. After 12 weeks, all hatchlings were transferred to clean soil and maintained at 15°C for 20 weeks until they showed evidence of a clitellum. In toxicity trials, F1 generation L. rubellus were exposed to 2,000 mg As/kg as sodium arsenate or 300 mg Cu/kg as copper chloride for 28 d. The F1 generation L. rubellus from Devon Great Consols mine demonstrated resistance to arsenate but not copper. All L. rubellus from Devon Great Consols kept in soil treated with sodium arsenate remained in good condition over the 28-d period but lost condition rapidly and suffered high mortality in soil treated with copper chloride. The control population suffered high mortality in soil treated with sodium arsenate and copper chloride. Previous work has shown that field-collected adults demonstrate resistance to both arsenate and Cu toxicity under these conditions. Thus, while arsenate resistance may be demonstrated in F1 generation L. rubellus from one of the contaminated sites, Cu resistance is not. The F1 adults and F2 cocoons did not have significantly higher levels of As than the control population, with no residual As tissue burden, suggesting that resistance to As in these populations may be inherited.
Interspecies quantitative structure-activity relationship model for aldehydes: Aquatic toxicity
Authors: Dimitrov Sabcho , Koleva Yana , Schultz T. Wayne , Walker John D. , Mekenyan Ovanes 
Published: November 2004

Abstract
The present study proposes a generic interspecies quantitative structure-activity relationship (QSAR) model that can be used to predict the acute toxicity of aldehydes to most species of aquatic organisms. The model is based on the flow-through fathead minnow (Pimephales promelas) 50% lethal concentration (LC50) data combined with other selected fish acute toxicity data and on the static ciliate (Tetrahymena pyriformis) 50% inhibitory growth concentration (IGC50) data. The toxicity of Schiff-base acting aldehydes was defined using hydrophobicity, as the calculated log 1-octanol/water partition coefficient (logKow), and reactivity, as the donor delocalizability for the aldehyde O-site (DO-atom). The fish model [log 1/LC50 = —2.503(±1.950) + 0.480(±0.052) log Kow + 18.983(±6.573) DO-atom, n = 62, r2 = 0.619, s2 = 0.241, F = 48.0, Q2 = 0.587] compares favorably with the ciliate model [log 1/IGC50 = —0.985(±1.309) + 0.530(±0.044) log Kow + 11.369(±4.350) DO-atom, n = 81, r2 = 0.651, s2 = 0.147, F = 72.9, Q2 = 0.626]. The fish and ciliate surfaces appear to be parallel, because they deviate significantly only by their intercepts. These observations lead to the development of a global QSAR for aldehyde aquatic toxicity [log E−1 = bOrganismE + 0.505(±0.033) log Kow + 14.315(±3.731) DO-atom, n — 143, r2 = 0.698, s2 = 0.187, s2Fish = 0.244, s2Ciliate = 0.149, F = 98, Q2 = 0.681]. The general character of the model was validated using acute toxicity data for other aquatic species. The aldehydes global interspecies QSAR model could be used to predict the acute aquatic toxicity of untested aldehydes and to extrapolate the toxicity of aldehydes to other aquatic species.
Effects of acid mine drainage on larval Chironomus (Diptera, Chironomidae) measured with the multispecies freshwater Biomonitor®
Authors: De Bisthoven Luc Janssens , Gerhardt Almut , Soares Amadeu M. V. M. 
Published: November 2004

Abstract
The abandoned São Domingos mine (Portugal) offers a pH and metal gradient of acid mine drainage (AMD), and is an ideal model for ecotoxicological studies. Short-term 24-h bioassays with water from the AMD (pH 3.3, 4.4, and 5.5, and control) were performed with fourth instars of Chironomus in the laboratory and in situ (AMD at pH 5.5) in artificial flow-through channels. This was compared to reference water acidified to the respective pH values (acid only). Behavioral stress responses were monitored online with the Multispecies Freshwater Biomonitor® (MFB). The exposure to AMD and acid only was in the sublethal range (mortality 0–20%). The use of MFB chambers did not affect survival. Stress behavior of Chironomus consisted mainly of decreased locomotory activity in AMD and increased activity in acid-only tests, indicating that the metals in the AMD played a role as stress factor. Field exposure in the AMD mixing zone (pH 5.5) generated similar activity as in the corresponding laboratory exposure.
Valve closure response to uranium exposure for a freshwater bivalve (Corbicula fluminea): Quantification of the influence of pH
Authors: Fournier Elodie , Tran Damien , Denison Francis , Massabuau Jean-Charles , Garnier-Laplace Jacqueline 
Published: November 2004

Abstract
Laboratory experiments were carried out to analyze the first valve closure response of a freshwater bivalve (Corbicula fluminea) exposed to uranium during a 5-h period. Experiments were performed in a well-defined artificial water at two pH values, 5.5 and 6.5, with a noninvasive method of valve recording. Sensitivity thresholds, based on percentage of bivalve that close their valves in a given time, were determined. Response thresholds depended on the total uranium concentration, integration time of response (fast responses could only be observed for the highest concentrations), and pH. The bivalve is much more sensitive to total uranium concentration at pH 5.5 than pH 6.5. The minimal sensitivity threshold determined, expressed as the uranium concentration inducing the valve closure of 50% of the bivalves, was 0.05 μmol/L at pH 5.5 after 5 h of exposure. Moreover, higher concentrations of the free ion UO22+ are required at pH 5.5 than at pH 6.5 to illicit the same response. Two hypotheses can be proposed, that UO22+ is not the only detected species or that competition exists between H+ and UO22+ for binding sites.
Reduced growth of rainbow trout (Oncorhynchus mykiss) fed a live invertebrate diet pre-exposed to metal-contaminated sediments
Authors: Hansen James A. , Lipton Joshua , Welsh Paul G. , Cacela David , MacConnell Beth 
Published: November 2004

Abstract
Juvenile rainbow trout (Oncorhynchus mykiss) were fed live diets of Lumbriculus variegatus cultured in metal-contaminated sediments from the Clark Fork River Basin (MT, USA), an uncontaminated reference sediment, or an uncontaminated culture medium. Fish were tested in individual chambers; individual growth as well as the nutritional quality and caloric value of each trout's consumed diet were determined. Growth was measured following 14, 28, 42, 56, and 67 d of exposure. A subset of fish was sampled at 35 d for whole-body metals. Metals (whole body, digestive tract, and liver) and histology were measured at the end of the test. We observed significant growth inhibition in trout fed the contaminated diets; growth inhibition was associated with reductions in conversion of food energy to biomass rather than with reduced food intake. Growth inhibition was negatively correlated with As in trout tissue residues. Histological changes in contaminated treatments included hepatic necrosis and degenerative alterations in gallbladder. The present study provides evidence that metal-contaminated sediments can pose a hazard to trout health through a dietary exposure pathway.
Differential toxicity of copper, zinc, and lead during the embryonic development of Chasmagnathus granulatus (Brachyura, varunidae)
Authors: Lavolpe Mariano , Greco Laura López , Kesselman Daniela , Rodríguez Enrique 
Published: November 2004

Abstract
Ovigerous females of the estuarine crab Chasmagnathus granulatus were exposed to copper (0.01 and 1 mg/L), zinc (0.05, 1, and 10 mg/L), or lead (0.01 and 1 mg/L) during early, late, or whole embryonic development. None of the assayed heavy metals produced a significant mortality of females, neither a decrease in the number of hatched larvae nor a decrease in the egg incubation time, but several morphological abnormalities were detected in hatched larvae. The abnormalities were classified in three categories: eye, body pigmentary, and body morphological abnormalities. Those larvae with eye and body pigmentary abnormalities, particularly those involving retinal pigments and chromatophores, showed the highest incidence by exposure to the assayed metals. In addition, embryos were more susceptible to copper and zinc during the late period of development, whereas the effect of lead was greater during the early period of embryogenesis. Some teratogenic effects observed in C. granulatus embryos exposed to heavy metals, particularly the hypertrophy and hypopigmentation of eyes observed in the laboratory at a lead concentration as low as that reported for the natural environment, could be considered as sensitive biomarkers for this kind of pollutant.
Multiple stress effects of Vision® herbicide, pH, and food on zooplankton and larval amphibian species from forest wetlands
Authors: Chen Celia Y. , Hathaway Kevin M. , Folt Carol L. 
Published: November 2004

Abstract
As part of a multiple-tier research program, interactions of the herbicide Visionn® (glyphosate) with two stressors, pH and food level, were examined. Effects of the formulated product Vision were tested at two test concentrations (0.75 and 1.50 mg acid equivalent/L), two pH levels (pH 5.5 and 7.5), and under high and low food concentrations. Effects of each stressor alone and in combination were examined using two common wetland taxa: Zooplankton, Simocephalus vetulus, and tadpoles (Gosner stage 25) of Rana pipiens. For S. vetulus, survival, reproduction, and development time were measured; survival was measured for R. pipiens. For both species, significant effects of the herbicide were measured at concentrations lower than the calculated worst-case value for the expected environmental concentration ([EEC], 1.40 mg acid equivalent/L). Moreover, high pH (7.5) increased the toxic effects of the herbicide on all response variables for both species even though it improved reproductive rate of S. vetulus over pH 5.5 in the absence of herbicide. Stress due to low food alone also interacted with pH 5.5 to diminish S. vetulus survival. These results support the general postulate that multiple stress interactions may exacerbate chemical effects on aquatic biota in natural systems.
Toxicity of model aliphatic amines and their chlorinated forms
Authors: Gong Woei-Long , Sears Keith Jason , Alleman James E. , Blatchley Ernest R. 
Published: November 2004

Abstract
Aliphatic amines can be found in many wastewater effluents from industry, agriculture, pharmacy, and food processing. Amines can induce toxicological responses that are relevant in biochemical treatment processes, as well as in natural waters. This research compared the toxicity and inhibition caused by three aliphatic amines (n-propylamine, ethylmethylamine, and trimethylamine) and their chlorinated derivatives. The chemistry of chlorine interactions with these compounds was characterized by using membrane introduction mass spectrometry (MIMS). Acute toxicity assays were conducted by using a Microtox® system with Phosphobacterium phosphoreum (also known as Vibrio fischeri) for the aliphatic amine compounds and their corresponding chlorinated derivatives, as identified by MIMS. Inhibition tests were conducted by using the oxygen utilization rate test with an enhanced nitrifier culture. The median effective concentration (EC50) values for chloropropylamine, chloroethylmethylamine, and chlorodimethylamine obtained by Microtox with a contact time of 15 min were 12.68, 19.72, and 15.92 μM, respectively. The EC50 values of these aliphatic chloramines from the Microtox test decreased by roughly one order of magnitude as a result of chlorination. Inhibition of nitrifiers also was observed in these amines. Trimethylamine and n-propylamine caused greater inhibition to nitrifiers than did ethylmethylamine under similar concentrations. Nitrifier inhibition from these amines increased after chlorination. The results of these tests indicated that aliphatic amines and their chlorinated derivatives could induce environmentally relevant toxicity responses in treatment settings and in receiving waters.
Sediment quality in the Atlantic coast of Spain
Authors: Riba Inmaculada , Casado-Martínez Carmen , Forja Jesús M. , Valls Ángel Del 
Published: November 2004

Abstract
Sediments from the Atlantic coast of Spain have been studied to evaluate environmental quality by using an integrated approach including chemical and toxicological data. Sediment samples were collected in four littoral ecosystems located in Spain, Bay of Cádiz, Guadalquivir River estuary, Ría of Huelva, and Ría of Coruña. To characterize the sediments, organic carbon, granulometric content, total sulfide, eight trace metals (Hg, Cd, Pb, Cu, Zn, As, Ni, and Cr), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were measured. The toxicity of sediments was assessed with the amphipod Ampelisca brevicornis, the clam Ruditapes philippinarum, juveniles of the fish Solea senegalensis, populations of the estuarine rotifer Brachionus plicatilis, and populations of the bacterium Vibrio fischeri (Microtox®). The results obtained show that in general, stations located in the Ría of Huelva were associated with heavy metal contamination and with the highest toxicity. Only chronic toxicity tests were capable of identifying the effects associated with PCB concentrations. The sediment quality guidelines calculated by means of a multivariate analysis approach for contaminants not associated with biological effects (mg/kg) are Hg, 0.54; Cd, 0.51; Pb, 260; Cu, 209; Zn, 513; As, 27.4; and total PCBs, 0.05.
Estimation of kinetic parameter for the biotransformation of three-ring azaarenes by the phenanthrene-degrading strain Sphingomonas SP LH128
Authors: Van Herwijnen René , De Graaf Chris , Govers Harrie A. J. , Parsons John R. 
Published: November 2004

Abstract
We examined the biotransformation of several azaarenes to get information on their rate of removal from contaminated soil by cometabolic degradation. Acridine, 9-methyl-acridine, phenanthridine, benzo[f]quinoline, and benzo[h]quinoline were found to be cometabolized by phenanthrene-degrading Sphingomonas sp. strain LH128. The transformation of acridine and benzo[h]quinoline was shown to be inhibited at relatively high concentrations (24.9 mg/L and 58.2 mg/L, respectively). Maximum biotransformation rates (Vmaxs), Michaelis-Menten half saturation constants (Kms), and biotransformation constants (k1s) were estimated for acridine, phenanthridine, and benzo[f]quinoline and ranged from 14.0 to 26.1 mg/g total protein/h for Vmax, 0.57 to 2.9 mg/L for Km, and 4.9 to 30.8 L/g total protein/h for k1. For 9-methyl-acridine only, a k1 of 0.6 L/g total protein/h was estimated and for benzo[h]quinoline, the highest biotransformation rate measured was 6.8 ± 0.4 mg/g total protein/h. To our knowledge, this is the first effort to determine both Vmax and Km kinetic parameters describing the biotransformation of phenanthrene- and anthracene-analogue azaarenes. The results show that the rate of removal of azaarenes from contaminated soil will probably be rather high, although accumulation of metabolites can be expected.
Indices for bioavailability and biotransformation potential of contaminants in soils
Authors: Braida Washington J. , White Jason C. , Pignatello Joseph J. 
Published: November 2004

Abstract
Bioavailability is an important consideration in risk assessment of soil contaminants and in the selection of appropriate remediation technologies for polluted sites. The present study examined the bioavailability and biodegradation potential of phenanthrene with respect to a pseudomonad in 15 different soils through separate measurements of mineralization, transformation, and desorption to a polymeric infinite sink (Tenax®) after 180-d sterile pre-equilibration with phenanthrene. Fractions strongly resistant to desorption and mineralization at long times were evident in all cases. After correcting for bioconversion (moles mineralized per mole transformed) determined in aqueous particle-free soil extracts, a correlation was found between the biotransformation-resistant fraction and the Tenax desorption-resistant fraction. Indices are proposed to assess bioavailability (BAt) and biotransformation potential (BTPt) of a compound in a soil based on parallel desorption and degradation studies over a selected period t. The BAt is the ratio of moles biotransformed to moles desorbed to an infinite sink, and it reflects the biotransformation rate relative to the maximal desorption rate. Values of BA30 (30-d values) ranged from 0.64 (for dark gray silt loam) to 1.12 (Wurtsmith Air Force Base [AFB] 2B, Oscoda, MI, USA). The BTPt is the ratio between moles biotransformed and moles of contaminant remaining sorbed after maximal desorption. The BTPt provides an indication of the maximum extent of biotransformation that may be expected in a system, assuming desorption is a prerequisite for biodegradation. Values of BTP30 ranged between 0.3 (Wurtsmith AFB 1B) and 13 (Mount Pleasant silt loam, NY, USA). The combination of BAt and BTPt provides insights regarding the relationship between physical availability (desorption) and biological processes (biotransformation kinetics, toxicity, other soil factors) that occur during biodegradation and are suggested to represent the remediation potential of the chemical. The BA30 values less than 0.9 and BTP30 values less than five indicate poor potential for site remediation.
Vapor pressures and enthalpies of sublimation of 17 polychlorinated dibenzo-p-dioxins and five polychlorinated dibenzofurans
Authors: Li Xian-Wei , Shibata Etsuro , Kasai Eiki , Nakamura Takashi 
Published: November 2004

Abstract
An apparatus for vapor pressure measurement with a very small cell by the mass-loss Knudsen effusion technique was tested with solid benzoic acid and anthracene. The vapor pressure and enthalpy of sublimation results of the two reference compounds were in good agreement with accepted literature data. The vapor pressures at different temperatures of 17 polychlorinated dibenzo-p-dioxins (including dibenzo-p-dioxin) and five polychlorinated dibenzofurans (including dibenzofuran) were measured with the apparatus, and the enthalpies of sublimation of the 22 dioxins and furans were derived from the temperature dependence of vapor pressure. The results were systematically compared with the literature data.
A comparative study on the relationship between acetylcholinesterase activity and acute toxicity in Daphnia magna exposed to anticholinesterase insecticides
Authors: Printes Liane Biehl , Callaghan Amanda 
Published: November 2004

Abstract
Acetylcholinesterase (AChE) activity was measured in Daphnia magna that had been exposed to four organophosphates (OPs; parathion, chlorpyrifos, malathion, and acephate) and one carbamate (propoxur) for 48 h. These results were related to acute toxicity (median effective concentration [EC50] for immobility). For the four OPs, the EC50s were 7.03 pM, 3.17 pM, 10.56 pM, and 309.82 μM, respectively. The EC50 for propoxur was 449.90 pM. Reduction in AChE activity was directly related to an increase in immobility in all chemicals tested. However, the ratio between the EC50 and the AChE median inhibiting concentration ranged from 0.31 to 0.90. A 50% reduction in AChE activity generally was associated with detrimental effects on mobility. However, for acephate, high levels of AChE inhibition (70%) were observed in very low concentrations and were not associated with immobility. In addition, increasing the concentration of acephate further had a slight negative effect on AChE activity but a strong detrimental effect on mobility. Binding sites other than AChE possibly are involved in acephate toxicity to D. magna. Our findings demonstrate different associations between AChE inhibition and toxicity when different chemicals are compared. Therefore, the value of using AChE activity as a biomarker in D. magna will be dependent on the chemical tested.