bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methyl mercury toxicokinetics in channel catfish (Ictalurus punctatus) and largemouth bass (Micropterus salmoides) after intravascular administration
Authors: Schultz Irvin R , Newman Michael C 
Published: March 2010

AbstractWe compared the differences in the distribution and elimination of CH3Hg after intraarterial injection and serial blood removal in catfish and bass of similar body size under consistent water quality conditions. The blood and plasma concentration-time profiles of individual fish were analyzed using a three-compartment, clearance-volume model. The plasma protein binding of CH3Hg was determined by ultrafiltration (30,000 mol. wt. cutoff) and the binding affinity (ρ) of CH3Hg for red blood cells (RBCs) was also calculated. Toxicokinetic analysis of the plasma concentration-time profiles provided the following values: apparent volume of distribution at steady state (Vss) = 30 ± 14 ml/g (catfish), 6.2 ± 2 ml/g (bass); total body clearance (Clb) = 0.026 ± 0.011 ml/h/g (catfish), 0.0057 ± 0.001 ml/h/g (bass). The values of Vss and Clb estimated from the blood concentration-time profiles in catfish and bass were fivefold lower. The elimination half-life from blood and plasma was between 814 and 1670 h and was not statistically different between species or reference fluid. The AUC0→∞ for blood was over three times higher than plasma, due to the binding of CH3Hg to RBCs. The unbound fraction of CH3Hg in bass plasma was 14-fold lower (0.25 vs. 3.64%) and the ρ for RBCs was 20 times greater than catfish (5,974 vs. 289). The decreased binding to plasma and RBCs in catfish is consistent with the increased extravascular distribution and clearance capacity of CH3Hg in catfish because a larger fraction of the CH3Hg in blood is available to distribute outside the vascular system.
Effects of surfactants on the rotifer,Brachionus calyciflorus, in a chronic toxicity test and in the development of qsars
Authors: Versteeg Donald J , Stanton David T , Pence Michael A , Cowan Christina 
Published: March 2010

AbstractThe toxicity of a range of surfactant and surfactant-related compounds was investigated in the 2-d whole life cycle bioassay with the rotifer, Brachionus calyciflorus. Compounds were selected to gain an understanding of how structural components, especially the polar head groups, contribute to toxicity. Rotifers were exposed under static test conditions to the 22 compounds for 2d. Exposure concentrations were verified analytically in the test system. Results demonstrate a relationship between alkyl chain length and toxicity within a surfactant class. Between classes, N-containing amines and quaternary ammonium compounds had greatest toxicity, in general, followed by the nonionic compounds. Anionic compounds were typically least toxic. A good quality (R2 = 0.86), three-variable, parametric QSAR model was developed using the ADAPT software package. The model contains one variable to account for the contribution of the hydrophobic tail group to observed toxicity (the number of sp3-hybridized carbons bonded to two other carbons [2SP3]) and two descriptors, the valence-corrected, fourth-order cluster index (4XvC) and a count of the number of nitrogens in the molecule (NN), to account for the contribution of the polar head group.
Cryopreservation of fluorescent marker-labeled algae (Selenastrum capricornutum) for toxicity testing using flow cytometry
Authors: Faber Marvin J , Smith Lisa M J , Boermans Herman J , Stephenson Gerald R , Thompson Dean G , Solomon Keith R 
Published: March 2010

Abstract
A rapid, two-stain (fluorescein diacetate and ethidium homodimer-1) flow cytometric assay to evaluat viability and cytotoxicity of the alga Selenastrum capricornutum in preserved samples is described. For storage, stained cells were fixed in glutaraldehyde, flash frozen in liquid nitrogen, and stored frozen (−20°C) for assessment at a later date. Weekly analysis of frozen samples showed that fluorescence was stable for 7 weeks. A mixture of 50% healthy and 50% heat-killed cells of S. capricornutum showed 36.1% healthy cells, 13.2% compromised cells, 12% nonstained cells, and 38.7% dead cells. This technique was tested using sodium dodecyl sulfate (SDS) and phenol as toxicants. Threshold concentrations for toxicant impact were in the range of 1 to 10 mg/L for SDS and 10 to 100 mg/L for phenol. Estimates of mortality showed 96-h median lethal concentration (LC50) values of 2,340 mg/L and 6,970 mg/L for SDS and phenol, respectively. This two-stain flow cytometric procedure has proven to be a reliable, sensitive assay for determining viability of S. capricornutum in preserved samples. The sensitivity of this dual-color assay and the ability to store samples for later analysis are significant improvements over current techniques.
Bacterial inoculants of forage grasses that enhance degradation of 2-chlorobenzoic acid in soil
Authors: Siciliano Steven D , Germida James J 
Published: March 2010

Abstract
Biological remediation of contaminated soil is an effective method of reducing risk to human and ecosystem health. Bacteria and plants might be used to enhance remediation of soil pollutants in situ. This study assessed the potential of bacteria (12 isolates), plants (16 forage grasses), and plant-bacteria associations (selected pairings) to remediate 2-chlorobenzoic acid (2CBA)-contaminated soil. Initially, grass viability was assessed in 2CBA-contaminated soil. Soil was contaminated with 2CBA, forage grasses were grown under growth chamber conditions for 42 or 60 d, and the 2CBA concentration in soil was determined by gas chromatography. Only five of 16 forage grasses grew in 2CBA-treated (816 mg/kg) soil. Growth of Bromus inermis had no effect on 2CBA concentration, whereas Agropyron intermedium, B. biebersteinii, A. riparum, and Elymus dauricus decreased 2CBA relative to nonplanted control soil by 32 to 42%. The 12 bacteria isolates were screened for their ability to promote the germination of the five grasses in 2CBA-contaminated soil. Inoculation of A. riparum with Pseudomonas aeruginosa strain R75, a proven plant growth-promoting rhizobacterium, increased seed germination by 80% and disappearance of 2CBA by 20% relative to noninoculated plants. Inoculation of E. dauricus with a mixture of P. savastanoi strain CB35, a 2CBA-degrading bacterium, and P. aeruginosa strain R75 increased disappearance of 2CBA by 112% relative to noninoculated plants. No clear relationship between enhanced 2CBA disappearance and increased plant biomass was found. These results suggest that specific plant-microbial systems can be developed to enhance remediation of pollutants in soil.
Interaction of Cd and Zn toxicity forFolsomia candidaWillem (Collembola: Isotomidae) in relation to bioavailability in soil
Authors: Van Gestel Cornelis A M , Hensbergen Paul J 
Published: March 2010

AbstractThe use of toxicity tests in which each chemical is tested separately is inadequate for assessing the potential risk of complex mixtures of chemicals for soil ecosystems. In the present study, the effects of Cd and Zn, alone or in combination, on the survival, growth, and reproduction of the collembolan Folsomia candida were determined after 2, 4, and 6 weeks of exposure in an artificial soil. The water solubility of Cd in the soil was significantly increased by the presence of Zn, whereas Cd did not affect the water solubility of Zn. In spite of this, uptake of Cd or Zn in the animals was not affected by the presence of the other metal, suggesting that water solubility does not determine the uptake of these metals in F. candida. For both Cd and Zn, reproduction was the most sensitive parameter, with 50% effective concentration (EC50) values of 51 and 683 μg/g dry soil, respectively, after 6 weeks. These values corresponded with internal concentrations of 44 μg Cd/g and 97 μg Zn/g dry body weight, respectively, while corresponding water-soluble EC50s were 0.13 μg Cd/g and 14 μg Zn/g dry soil, respectively. Although a proper comparison of the effects of mixtures of the metals with the effects of the individual metals was sometimes hampered by the nonsimilarity of dose-response relationships, it may be concluded that the effects of the mixture of Cd and Zn on the growth of F. candida are antagonistic (EC50 significantly greater than 1.0 toxic unit), while the effects on reproduction are additive (EC50 = 1.0 toxic unit). Similar conclusions could be drawn for EC50s expressed on the basis of total and water-soluble soil concentrations as well as on the basis of internal concentrations in the animals. Analysis of the combined effects of Cd and Zn at the 10% effective concentration level did not change these conclusions.
2,4-D dissipation in field soils after applications of 2,4-D dimethylamine salt and 2,4-D 2-ethylhexyl ester
Authors: Wilson Ronald D , Geronimo Joseph , Armbruster James A 
Published: March 2010

Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D) was first registered in 1947 as an agricultural herbicide, and it is still the most widely used herbicide worldwide. End-use products, however, are generally formulated as inorganic or amine salts, or as esters. Because of the various forms available, there was concern that by testing only one form, the environmental profile generated might be insufficient to represent all forms. Therefore, as part of the 2,4-D reregistration process in the U.S., 30 soil dissipation studies were conducted with 2,4-D dimethylamine salt and 2,4-D 2-ethylhexyl ester over a 2-year period. Trials were located in seven states and included four cropping practices and bare soil. The results, averaged over all conditions, showed equivalent rates of 2,4-D dissipation in soil when applied as either the amine salt or ester forms. These results also confirm data from earlier field studies in Canada and Washington state showing equivalent 2,4-D dissipation in soil from applications of isooctyl ester, dimethylamine salt, and mixed amine salt forms. The data from the current and former studies show that ester and amine forms have little effect on the rate of dissipation of 2,4-D per se because they are converted rapidly to the same anionic form.
Toxic effects of linear alkylbenzene sulfonate, quaternary alkylammonium chloride and their complexes on Dunaliella sp. and Chlorella pyrenoidos
Authors: Utsunomiya Akiko , Watanuki Tomohiko , Matsushita Kazuhiro , Tomita Isao 
Published: March 2010

Abstract
The toxic effects of linear alkylbenzene sulfonate (LAS), quaternary alkylammonium chlorides (cationic surfactants[CS]), and their complexes (LAS-CS) were examined in Dunaliella sp. by proton nuclear magnetic resonance spectroscopic analysis of glycerol and in Chlorella pyrenoidosa by growth inhibition. The glycerol content decreased quantitatively with increased concentrations of LAS, CS, and LAS-CS complexes. The 24-h median effective concentration (EC50] values of LAS and CS in free form were 0.38 to 18 mg/L and the toxic effects were in the order alkyltrimethylammonium chloride (TM) &gt; alkyldimethylbenzylam-monium chloride (BM) &gt; LAS &gt; dialkyldimethylammonium chloride (DM). The 24-h EC50 values of LAS-CS complexes at molar ratios of 1:1 and 2:1 were 1.3 to 13 and 5.6 to 9.6 mg/L as LAS-equivalent concentration, respectively. The order of toxic effects was LAS-TM &gt; LAS = LAS-BM &gt; 2LAS-BM &gt; 2LAS-DM &gt; 2LAS-TM &gt; LAS-DM. The toxic effect of LAS was enhanced by equimolar complex formation with TM. The 96-h EC50 values of LAS and CS on the inhibition of growth in C. pyrenoidosa were 0.28 to 29 mg/L for the compounds in free form and their toxic effects were in the order TM &gt; BM ≫ DM &gt; LAS. The 96-h EC50 values of LAS-CS complexes at molar ratios of 1:1 and 2:1 were 1.4 to 59 and 11 to 86 mg/L, respectively, and the order of toxic effects was LAS-BM &gt; LAS-TM &gt; 2LAS-BM &gt; 2LAS-TM &gt; LAS &gt; LAS-DM &gt; 2LAS-DM. The toxic effects of LAS were also enhanced by the formation of complexes with TM or BM at molar ratio of 1:1 and 2:1. Thus, not only LAS but also its CS complexes might exert toxic effects on organisms in the environment.
Selenium toxicity to aquatic life: An argument for sediment-based water quality criteria
Authors: Canton Steven P , Van Derveer William D 
Published: March 2010

Abstract
A number of streams in Colorado were found to contain waterborne selenium concentrations that consistently exceeded the current U.S. EPA chronic criterion of 5 μg/L and often exceeded the acute criterion of 20 μg/L. Despite these elevated concentrations, no biological impact was observed. These findings led to a review of selenium exposure pathways in freshwater. The literature strongly indicates that chronic selenium toxicity can result from accumulation of selenium in the sediment, movement into the food chain, and resulting dietary uptake. Chronic toxicity does not appear to be strictly a result of waterborne selenium concentrations. In fact, dissolved selenium concentrations are a poor predictor of potential chronic toxicity to freshwater organisms, when evaluated with Hill's criteria for causal association. To develop a more reliable chronic waterborne criterion, a sediment-based method is needed to describe accurately potential chronic toxicity of selenium on a site-specific basis.
Toxicity and bioaccumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin in long-term tests with the freshwater benthic invertebratesChironomus tentansandLumbriculus variegatus
Authors: West Corlis W , Ankley Gerald T , Nichols John W , Elonen Gregory E , Nessa David E 
Published: March 2010

AbstractTwo species of freshwater benthic invertebrates, Chironomus tentans and Lumbriculus variegatus, were exposed to three dietary concentrations of 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD), and toxicity and bioaccumulation were determined. No toxic effects were observed in full life cycle tests with either species at tissue residue concentrations up to 9,533 ng TCDD/g lipid. The observed lack of sensitivity of the two species to TCDD was consistent with a presumed absence of the aryl hydrocarbon receptor in aquatic invertebrates. Predictions of lipid-normalized tissue concentrations were made based on lipid-normalized TCDD concentrations in the food and were within 15% of targeted concentrations in both species. Depuration studies indicated that TCDD elimination followed first-order kinetics, with elimination rate constants of 0.0014 to 0.0022 h−1 for L. variegatus and 0.0070 to 0.0099 h−1 for C. tentans. Half-lives ranged from 315 to 495 h in L. variegatus and from 70 to 99 h in C. tentans. The ability of invertebrates to accumulate relatively high concentrations of TCDD in the absence of toxic effects may be relevant to the transfer of contaminants through aquatic food webs to potentially sensitive vertebrate species.
Revised approach to toxicity test acceptability criteria using a statistical performance assessment
Authors: Thursby Glen B , Heltshe James , Scott K John 
Published: March 2010

Abstract
Current acceptability requirements for toxicity tests are often more restrictive than necessary. They focus primarily on response in a control and generally ignore what a test was “designed” to detect as a significant difference from that control. An approach is presented that takes into account the performance of an entire test and the magnitude of the deviation from the current acceptability requirements. The procedure is based on analyzing the past statistical performance of a test method (i.e., what kind of difference from the control was the test designed to detect). It takes into account traditional control acceptance criteria, but adds a requirement for selecting a difference from the control desired to be detected as statistically significant (a threshold value). Choice of statistical procedure is not relevant to the approach. The proposed method allows a sliding scale of acceptance. The greater the deviation of mean control response below current requirements, the less likely a test is to be accepted. An example is presented using data from a 10-d sediment test using the marine amphipod Ampelisca abdita. Use of the proposed acceptability criterion will reduce the frequency of required retesting without sacrificing defensibility of data. Using the old acceptability criterion, 19% of the samples in the amphipod data set would require retesting. The proposed criterion reduces the potential percentage of retests to 9%.
Does cadmium pollution change trophic interactions in rockpool food webs?
Authors: Koivisto Sanna , Arnér Marie , Kautsky Nils 
Published: March 2010

Abstract
We studied the regulation of phytoplankton and zooplankton biomass in rockpool food webs under chronic cadmium pollution. Experimental food webs with two and three trophic levels were composed of phytoplankton, small-bodied zooplankton (Chydorus sphaericus, Cyclops sp., and rotifers), Daphnia magna, and Notonecta sp., a zooplanktivorous predator. Every food web received a control and cadmium treatment allowing a separate study of cadmium and predation effects. After a 3-week stabilization period, cadmium and Notonecta were added and changes in primary productivity, chlorophyll, zooplankton species composition, and biomass were followed during 8 weeks. The results showed that phytoplankton and Daphnia were consumer regulated in both control and cadmium treatments, although resource availability ultimately determined the biomass at each trophic level. Daphnia was the only zooplankton species that reduced phytoplankton and also the only species that was eliminated by Notonecta predation. Notonecta had an indirect positive impact on phytoplankton biomass that increased after the extinction of Daphnia. Cadmium significantly reduced phytoplankton and Daphnia but did not change the trophic interactions between them, i.e., Daphnia and chlorophyll were significantly negatively correlated both in the control and cadmium treatments. Cadmium did not affect the relationship between Daphnia and Notonecta.
Analytical evaluation of laboratories wishing to perform environmental characterization studies
Authors: Lauenstein Gunnar G , Cantillo Adriana Y 
Published: March 2010

Abstract
Laboratories competing to analyze bivalve mollusks under contract to the National Oceanic and Atmospheric Administration's Mussel Watch Project were required to undergo analytical tests of their ability to quantify environmental contaminants as part of the contract evaluation process. During the 1989 selection process laboratories that appeared to qualify on the basis of their written proposals were provided a gravimetrically prepared solution with “unknown” quantities of an undefined number of organic contaminants that are regularly quantified for the Mussel Watch Project. In 1994, competing laboratories were once again tested but this time using matrix materials for the quantification of both trace elements and organic contaminants. Three laboratory groups participated in the exercises. For the 1989 gravimetrically prepared solutions, all participating laboratories were able to identify the contaminants present and in all but two cases were able to report values to within ±25% of the known values. In 1994, all laboratories were within the acceptance criteria for the quantification of trace elements in the homogenate sample. Analytical laboratory testing is an important first step to ensure that environmental characterization studies are successful.
Toxic effects of some benzamines on the growth of Azotobacter vinelandii and other bacteria
Authors: Chung King-Thom , Chen Ssu-Ching , Zhu You-Yan , Wong Tit Yee , Stevens S Edward 
Published: March 2010

Abstract
Benzamines are the major aromatic amines used in industry and can also be released from azo dyes, which are widely used in the textile, paper-making, and food industries. The toxicity of 10 benzamines was tested by the well diffusion assay technique against 18 common bacterial species including the nitrogen-fixing bacterium Azotobacter vinelandii. p-Phenylenediamine was found to be inhibitory to the growth of Aeromonas hydrophila and Pseudomonas fluorescens. o-Phenylenediamine was inhibitory to Escherichia coli, Klebsiella pnemoniae, Salmonella enteritidis, and Shigella sonnei. 2,5-Diaminotoluene was inhibitory to the growth of P. fluorescens and Streptococcus mitis. The growth of A. vinelandii was inhibited by p-phenylenediamine and 2,5-diaminotoluene in the well diffusion assay. p-Nitroaniline was also found to be inhibitory to the growth of A. vinelandii in Burk's nitrogen-free medium. The nitrogenase activity of A. vinelandii was inhibited by p-phenylenediamine, 2,5-diaminotoluene, p-nitroaniline, 2-nitro-p-phenylenediamine, 3-nitro-o-phenylenediamine, and 4-nitro-o-phenylenediamine. Because many of these organisms are common soil and aquatic bacteria, the accumulation of these benzamine compounds in the environment may have an adverse impact on soil biochemical activities.
Acute toxicity of fire-retardant and foam-suppressant chemicals to Hyalella azteca (Saussure)
Authors: McDonald Susan F , Hamilton Steven J , Buhl Kevin J , Heisinger James F 
Published: March 2010

Abstract
Acute toxicity tests were conducted with Hyalella azteca Saussure (an amphipod) exposed in soft and hard waters to three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex). The chemicals were slightly to moderately toxic to amphipods. The most toxic chemical to amphipods in soft and hard water was Phos-Chek WD-881 (96-h mean lethal concentration [LC50] equal to 10 mg/L and 22 mg/L, respectively), and the least toxic chemical to amphipods in soft water was Fire-Trol GTS-R (96-h LC50 equal to 127 mg/L) and in hard water was Fire-Trol LCG-R (96-h LC50 equal to 535 mg/L). Concentrations of ammonia in tests with the three fire retardants and both water types were greater than reported LC50 values and probably were the major toxic component. Estimated un-ionized ammonia concentrations near the LC50 were frequently less than the reported LC50 ammonia concentrations for amphipods. The three fire retardants were more toxic in soft water than in hard water even though ammonia and un-ionized ammonia concentrations were higher in hard water tests than in soft water tests. The accidental entry of fire-fighting chemicals into aquatic environments could adversely affect aquatic invertebrates, thereby disrupting ecosystem function.
Separation of 2,3,3′,4′,6-pentachlorobiphenyl (IUPAC 110) from 3,3′,4,4′-tetrachlorobiphenyl (IUPAC 77) using high-performance liquid chromatography
Authors: Qi Min , Anderson Michael 
Published: March 2010

Abstract
A double forward–reverse (DFR) flow high-performance liquid chromatography (HPLC) technique was developed for the separation of coplanar chlorobiphenyl (CB) congener 77 and nonplanar CB congener 110. The DFR separated these two congeners into different HPLC fractions; each fraction was analyzed using gas chromatography–electron capture detection. The method was successfully applied in the analysis of Aroclor mixtures and fish samples.