bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic Studies of Some Organic Azides
Authors: Abu-Eittah R. , El-Shahawy A.
Published: October 2005

The absorption spectra of some organic azides have been studied in the visible and uv region using different solvents. Interpretation of the obtained results is attempted. The different transitions obtained are assigned to either intramolecular charge–transfer transitions or to locally excited ones. The energies of the charge–transfer states are computed. No evidence was found for an n → π* transition.
A New Optical System for Flame Spectroscopy with Special Reference to Thermally Assisted Anti-Stokes Fluorescence Applications
Authors: Benetti P. , Omenetto N. , Rossi G.
Published: October 2005

A new optical setup for increasing the intensity of atomic fluorescence flame spectrometry is presented. The arrangement consists of two concave spherical mirrors and an elliposidal mirror whose primary focus is located at the flame position, and secondary at the entrance slit of the monochromator. Approximately 10 times gain in the measured intensities was obtained. The system is also useful for flame emission work, for which about five times gain was observed. With a low background flame such as the air–H2 for the N2−H2 diffusion flame and 400 µ slits, calcium can be detected at the level of 0.005 µg/ml. Moreover, the observed thermally assisted anti-Stokes fluorescence of In and Ga can be of analytical importance since the detection limits with a total consumption burner and the air-H2 flame were found to be 0.015 and 0.02 µg/ml, respectively. Detection limits in atomic fluorescence for Cr, Tl, In, and Fe are also presented.
Measurements of Chemical Shifts in the Photoelectron Spectra of Arsenic and Bromine Compounds
Authors: Hulett L. D. , Carlson T. A.
Published: October 2005

Chemical shifts in the binding energies of electrons in 3 d orbitals of bromine and arsenic have been measured by photoelectron spectroscopy, using soft x rays. The bromine salts studied were KBr, KBrO3, and KBrO4; the results are compared to corresponding chlorine and iodine salts studied by other workers. For a given increase in oxidation number, the shift (increase) in binding energy of bromine is intermediate to those for chlorine and iodine, chlorine shifts are higher, and iodine shifts are lower. This trend can be qualitatively explained by Hartree-Fock calculations of differences in binding energies for free halogen ions. Chemical shifts for arsenic can be correlated to variations in the effective charges on arsenic caused by different chemical environments. Calculations of the charge were made by considering the partial ionic character of bonds. A demonstration that photoelectron spectroscopy can be used in arsenic pollution problems has been made.
The Design of a Portable Polychromator to Monitor Contaminants in Tungsten Arc—Inert Gas Shields
Authors: Loseke W. A. , Grove E. L. , Gordon E. S.
Published: October 2005

A small portable spectrometer was developed to monitor oxygen and hydrogen as the free or dissociation products in the tungsten arc–inert gas welding process. The hydrogen (6562.8 Å) and oxygen (7771.9 Å) lines were monitored and the argon (8521.4 Å) line was used for the internal standard. The instrument, a fixed Eagle mount, used a 76×50 mm, 60 cm focal length, concave grating with 610 grooves/mm blazed in the second order. The reciprocal dispersion at 6562 Å was 12 Å/mm. The oxygen triplet was resolved. Optical design requirements included the use of very short arc lengths in the order of 0.5 mm and less, an optical plane of 65° to 75deg; with a large flat plate instead of the conventional 90° with respect to the electrodes, and an arc that does not remain in a fixed optical position in space. The focusing lens-limiting aperture assembly was mounted on the torch head with a fiber optic bundle transmitting the light to the spectrometer. The instrument recorded only the signal above background, including the very high background produced by introducing the electrode tip into the optical path. This was accomplished by the use of an oscillating optical block in the entrance beam which yields an ac signal above the dc signal from background. The direct ratio readout system used a Devar ratio computer in each analytical channel and was essentially instantaneous.
Some Recent Advances in Photoelectron Spectroscopy
Authors: Brundle C. R.
Published: October 2005

A summary of the instrumentation and principles involved in photoelectron spectroscopy is presented. Brief descriptions of the available commercial instruments are given. Results both in the low energy area (molecular photoelectron spectroscopy) and the high energy area (ESCA) are reviewed, with emphasis on recent data and/or controversial new areas of study.
Electron Impact Spectrometer for Gas Analysis
Authors: Rendina John F. , Grojean Richard E.
Published: October 2005

Electron spectroscopy for chemical analysis (ESCA) is proving to be a most valuable technique for the analytical chemist and molecular physicist. A commercially available Simpson–Kuyatt-type electron impact spectrometer for gas and vapor studies is described. High resolution electron transition spectra of gases, covering the equivalent wavelength range of x ray to infrared, are quickly and accurately obtained with this spectrometer. Ideally suited for quantitative and qualitative gas analysis, this new instrument will find extensive applications ranging from air pollution studies to molecular and atomic structural analysis.
An Improved Semiquantitative Spectrochemical Method
Authors: Long T. S.
Published: October 2005

A critical examination of commonly used semiquantitative techniques has been completed. Improved precision and accuracy have allowed analysis on sample sizes of 10 mg with no prior knowledge of chemical composition. A comparison of various matrices such as graphite, lithium carbonate, and lithium fluoride is included. Data on the precision and accuracy of each matrix in air and argon–oxygen atmospheres are also presented. A lithium fluoride–graphite matrix showed the best over-all results. The deviation from established values was approximately 15% and the coefficient of variation was also 15%. This study was completed under rigorous conditions with single determinations. Results were taken over a two year period and nearly 500 single determinations were used to complete the data.
A Mass Spectrometric Investigation of the Thermal Desorption of Atmospheric Gases from Plutonium Dioxide. I. Radiolytically Produced Nitric Oxide
Authors: Stakebake Jerry L. , Loser Robert W. , Chambers Carey A.
Published: October 2005

A technique is developed for measuring the thermal desorption of one or more gases using the time-of-flight mass spectrometer. With this method the adsorbed population, gas-solid bond energy, and preexponential kinetic factor can be determined for each adsorbed gas. The thermal desorption of nitric oxide from plutonium dioxide was measured over the temperature range 100°–900°C and typical spectra are presented. The activation energy of desorption was found to be 19.4 kcal/mole. The probable mechanism for adsorption is also discussed.
Effect of the Slit Function of the Detection System and a Fast-Fitting Algorithm on Accuracy of CARS Temperature
Authors: Park Seung Nam , Hahn Jae Won , Rhee Chunghi
Published: October 2005

The effect of the erroneous functional forms of the slit functions on the best-fit temperature in CARS (coherent anti-Stokes Raman spectroscopy) thermometry has been investigated. When the shape of the slit function is described as a Lorentzian or a Gaussian function and its width adjusted with the room-temperature CARS spectrum, the maximum systematic errors due to the slit functions reach 1.5–2.5% in the temperature range from 300 to 2100 K. A fast-fitting algorithm exponentially interpolating the CARS spectrum at an intermediate temperature with two precalculated spectra has been proposed, and its validity has been assessed by calculating the error due to the fitting algorithm.
Effects of Heavy-Atom Salts on the Luminescence Properties of Tetrol I-1 on α-Cyclodextrin/Salt Matrices
Authors: Corley Johannes , Hurtubise Roert J.
Published: October 2005

Benzo( a)pyrene [B(a)P] is one of the most widely studied polyaromatic hydrocarbons. In the human body and in lower animals, B(a)P can become chemically bonded to DNA. Tetrols are the products obtained from the hydrolysis of B(a)P-DNA adducts. It has been proposed that the amount of tetrols detected in human body fluids can be used as a measure of the amount of B(a)P-DNA adducts present in the body. The effects of several heavy-atom salts on the solid-matrix fluorescence and phosphorescence properties of the tetrols were investigated. TINO3 and TIF were very useful in enhancing the room-temperature phosphorescence (RTP) of the tetrols. For tetrol I-1 on 1:1:8 α-cyclodextrin:TlNO3: NaNO3, the limit of detection was 0.38 femtomole/mg. The RTP approach with the 1:1:8 α-cycIodextrin:TlNO3:NaNO3 matrix would be useful for detecting subfemtomole quantities of the tetrols of B(a)P-DNA adducts from biological samples.
Performance of a Spatial-Filter-Equipped Single Monochromator for Raman Spectroscopy
Authors: Trulson Mark O. , Lueck Horst B. , Friedrich Donald M.
Published: October 2005

A technique for reducing stray-light artifacts in Raman spectroscopy is described. The performance of a spatial filter at the output of a single monochromator is reported. The filter reduces both the diffuse background and the scattered-light artifacts encountered in single monochromators while maintaining high luminous throughput. Unlike other wavelength-selective methods for rejecting laser-excitation light (such as use of holographic edge or notch filters), spatial filtering of scattering artifacts may be used with any excitation wavelength. This is an advantage for Raman spectroscopy in the quartz ultraviolet region where holographic filters are not yet available. The enhanced ability to observe low-wavenumber scattering with an optical multichannel detector on a single monochromator is a particular advantage of the method.
FT-IR Transmission Spectroscopy for Quantitation of Ammonium Bisulfate in Fine-Particulate Matter Collected on Teflon® Filters
Authors: Krost K. J. , McClenny W. A.
Published: October 2005

A quantitative measurement method for the determination of fine-particle bisulfate in ammonium bisulfate collected from the ambient air onto Teflon® filters is described. Infrared absorbance measurements of the Teflon® filters are made before and after particle collection. Subtraction of the two spectra reveals the absorbance spectrum of the particles. The presence of bisulfate is identified by characteristic and unique spectral features including prominent absorption bands at 1050 and 870 cm−1. The integrated band absorbance at 870 cm−1 is used for quantitation. Wet chemical measurements of sulfate and hydrogen ion in synthetically generated ammonium bisulfate standards are used in calibration. The lower limit of detection for the bisulfate ion is 150 nanomoles. This amount corresponds to the ammonium bisulfate which would be collected from an air volume containing 1.2-microgram/m3 samples for 24 hours at 10.0 L/min. This method provides a specific, nondestructive, direct measurement of ammonium bisulfate. As such, the method has distinct advantages over indirect methods for the determination of bisulfate ion.
Electrothermal Atomization with Atomic Absorption at Reduced Pressures for Studies of Analyte Distribution in Solids
Authors: Wang Pingxin , Holcombe James A.
Published: October 2005

The spatial distribution of Pb in a NIST Standard Reference Material (SRM) C1253a copper alloy is determined by using an electrothermal atomizer atomic absorption spectrometry (ETA-AAS) system operated at reduced pressure. Three Pb absorbance peaks have been consistently observed at 0.1 Torr. It is proposed that the first peak belongs to the release process of Pb from the surface, the second peak may originate from grains until the Cu-Pb binary phase transformation to a homogeneous solution occurs, and the third peak arises from Pb in the bulk of the sample. The areas of the first two peaks may be used to determine the “near surface” and grain concentrations of analyte. However, the expulsion of analyte because of the coincident bulk vaporization of copper matrix produces a severely depressed analytical signal for the third peak. The data presented for the pressure-regulated ETA-AAS system suggest the feasibility of isolating and quantitatively measuring metals within the bulk and on or near the surface of solid samples when the metal of interest is of lower volatility than the host matrix.
Investigation of Different Polymers as Coating Materials for IR/ATR Spectroscopic Trace Analysis of Chlorinated Hydrocarbons in Water
Authors: Göbel R. , Krska R. , Kellner R. , Seitz R. W. , Tomellini S. A.
Published: October 2005

Polymer-coated attenuated total reflection (ATR) elements have been used to compare the diffusion behavior and enrichment from aqueous solutions of three different chlorinated hydrocarbons (CHCs) — monochlorobenzene (MCB), chloroform (CF), and tetrachloroethylene (TeCE)—into different polymers. The influence of polymer properties such as glass transition temperature and crystallinity and the effect of the polymer background IR absorption and varying thicknesses of the polymer membranes to the detectability were investigated. The crystallinity and the glass transition temperature have a very pronounced influence on the velocity of the diffusion process, whereas the partition coefficient influences the amount of CHC diffusing into the polymer membrane. The time constants for 90% saturation of the polymer with the test analytes are in the range of 8 to 40 min, depending on the nature of the polymer and analyte. A linear calibration graph was obtained for simultaneous detection of all three test analytes in the range from 5 mg/L to 100 mg/L CHC with detection limits of 1.5 to 2 mg/L. Coefficients for CHC partitioning between water and polymers measured by ATR/IR were in good agreement with values determined by GC/MS.
‘Discovery’ as a site for the collective construction of scientific knowledge
Authors: CANEVA KENNETH L.
Published: October 2005

Hans Christian Ørsted and Thomas Johann Seebeck are recognized as the discoverers of electromagnetism and thermoelectricity. Yet what each man believed he had discovered differed markedly from what many contemporaries saw in those discoveries and from subsequent canonized representations of them. The central historical concern of this paper is to track the details of how scientists' understanding of what was discovered in these two cases, as embodied in their preferred language, evolved over time in response to different interests, conceptual preferences, and ontological beliefs. The very concept of discovery, in accordance with which scientists bestow recognition only on someone who has discovered something held to be true of the world, plays an important role in the process of consensus formation by the interacting collectivity of scientists. In its historiographical assessment of such episodes, this study builds upon Thomas Kuhn's recognition that “discovering a new sort of phenomena is necessarily a complex process which includes recognizing both that something is and what it is”; upon augustine Brannigan's analysis of the social construction of discovery accounts, whereby “the attribution of discovery is structured…by the perception that the achievement is coherent with existing knowledge in the field”; and upon Ludwik Fleck's analysis of the creative role of an interacting “thought collective” in the “genesis and development of a scientific fact.”
At the Whim of the State: Neoliberalism and Nongovernmental Organizations in Guerrero, Mexico
Authors: Yaworsky William R.
Published: October 2005

This paper examines the relationship between the Secretaría de Desarrollo Social (SEDESOL) and nongovernmental organizations (NGOs) in the Chilapa region of Guerrero, Mexico. I argue that the Mexican state via SEDESOL has effectively harnessed NGOs to perform as regional pillars of neoliberal reform initiatives. The intimacy of this relationship raises serious questions for those who see NGOs performing as vehicles for furthering local or regional "autonomy." Instead, I argue that regional NGOs are key role players in the deepening incorporation of communities into the global industrial economy.

Este artículo examina las relaciones entre la Secretaría de Desarrollo Social (SEDESOL) y las organizaciones no-gubernamentales (ONGs) en la región de Chilapa, Guerrero, en México. A lo largo del texto, demuestro que el Estado Mexicano y SEDESOL utilizan ONGs para que éstas funcionen como pilares del programa neoliberal en la región. Esto contradice la función de las ONGs como instancias que permiten a las comunidades rurales obtener más autonomía. En los hechos, empero, y según lo sostengo, las ONGs de la región fundan bases importantes de la economía capitalista global.
An evaluation of logistic regression models for predicting amphipod toxicity from sediment chemistry
Authors: Wetherington Jeffrey D. , Stanley Bruce H. , Adams Kathleen O. , Schwer Richard F.
Published: October 2005

An empirical screening level approach was developed to assess the probability of toxicity to benthic organisms associated with contaminated sediment exposure. The study was based on simple logistic regression models (LRMs) of matching sediment chemistry and toxicity data retrieved from a large database of field-collected sediment samples contaminated with multiple chemicals. Three decisions were made to simplify the application of LRMs to sediment samples contaminated with multiple chemicals. First, percent mortality information associated with each sediment sample was condensed into a dichotomous response (i.e., toxic or nontoxic). Second, each LRM assumed that toxicity was attributable to a single contaminant. Third, individual contaminants present at low concentrations were excluded from toxic sediment samples. Based on an analysis of the National Sediment Inventory database, the LRM approach classified 55% of nontoxic sediments as toxic (i.e., false-positives). Because this approach has been used to assess the probability of benthic toxicity as reported by the U.S. Environmental Protection Agency (U.S. EPA), the resultant estimates of potential toxicity convey a misleading impression of the increased hazard that sediments pose to the health of aquatic organisms at many sites in the United States. This could result in important resources needlessly being diverted from truly contaminated sites to evaluate and possibly remediate sediments at uncontaminated sites.
Predicting sediment metal toxicity using a sediment biotic ligand model: methodology and initial application
Authors: Di Toro Dominic M. , McGrath Joy A. , Hansen David J. , Berry Walter J. , Paquin Paul R. , Mathew Rooni , Wu Kuen Benjamin , Santore Robert C.
Published: October 2005

An extension of the simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) procedure is presented that predicts the acute and chronic sediment metals effects concentrations. A biotic ligand model (BLM) and a pore water—sediment partitioning model are used to predict the sediment concentration that is in equilibrium with the biotic ligand effects concentration. This initial application considers only partitioning to sediment particulate organic carbon. This procedure bypasses the need to compute the details of the pore-water chemistry. Remarkably, the median lethal concentration on a sediment organic carbon (OC)—normalized basis, SEM*x,OC, is essentially unchanged over a wide range of concentrations of pore-water hardness, salinity, dissolved organic carbon, and any other complexing or competing ligands. Only the pore-water pH is important. Both acute and chronic exposures in fresh- and saltwater sediments are compared to predictions for cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) based on the Daphnia magna BLM. The SEM*x,OC concentrations are similar for all the metals except cadmium. For pH = 8, the approximate values (μmol/gOC) are Cd-SEM*x,OC ⋍ 100, Cu-SEM*x,OC ⋍ 900, Ni-SEM*x,OC ⋍ 1,100, Zn-SEM*x,OC ⋍ 1,400, and Pb-SEM*x,OC ⋍ 2,700. This similarity is the explanation for an empirically observed dose—response relationship between SEM and acute and chronic effects concentrations that had been observed previously. This initial application clearly demonstrates that BLMs can be used to predict toxic sediment concentrations without modeling the pore-water chemistry.
Significance testing of synergistic/antagonistic, dose level-dependent, or dose ratio-dependent effects in mixture dose-response analysis
Authors: Jonker Martijs J. , Svendsen Claus , Bedaux Jacques J.M. , Bongers Marina , Kammenga Jan E.
Published: October 2005

In ecotoxicology, the state of the art for effect assessment of chemical mixtures is through multiple dose—response analysis of single compounds and their combinations. Investigating whether such data deviate from the reference models of concentration addition and/or independent action to identify overall synergism or antagonism is becoming routine. However, recent data show that more complex deviation patterns, such as dose ratio—dependent deviation and dose level—dependent deviation, need to be addressed. For concentration addition, methods to detect such deviation patterns exist, but they are stand-alone methods developed separately in literature, and conclusions derived from these analyses are therefore difficult to compare. For independent action, hardly any methods to detect such deviations from this reference model exist. This paper describes how these well-established mixture toxicity principles have been incorporated in a coherent data analysis procedure enabling detection and quantification of dose level—and dose ratio—specific synergism or antagonism from both the concentration addition and the independent action models. Significance testing of which deviation pattern describes the data best is carried out through maximum likelihood analysis. This analysis procedure is demonstrated through various data sets, and its applicability and limitations in mixture research are discussed.
Effects of the polycyclic aromatic hydrocarbon heterocycles, carbazole and dibenzothiophene, on in vivo and in vitro cypia activity and polycyclic aromatic hydrocarbon-derived embryonic deformities
Authors: Wassenberg Deena M. , Nerlinger Abby L. , Battle Lauren P. , Di Giulio Richard T.
Published: October 2005

Herocyclic derivatives of polycyclic aromatic hydrocarbons (PAHs) are often significant components of environmental contaminant mixtures; however, their contribution to the toxicity of these mixtures is not well characterized. These heterocycles commonly co-occur in PAH mixtures, which contain agonists for the aryl hydrocarbon receptor (AHR). Our goal for these studies was to explore the effects of two PAH heterocycles, carbazole (CB) and dibenzothiophene (DBT), alone and in combination with a PAH-type agonist for the AHR (β-naphthoflavone [BNF]) on AHR-mediated cytochrome P4501A (CYP1A) activity and on fish embryotoxicity. Embryos of Fundulus heteroclitus were exposed to CB or DBT, with and without coexposure to BNF. Carbazole alone slightly induced, whereas DBT alone slightly reduced, in ovo CYP1A-mediated ethoxyresorufin-O-deethylase (EROD) activity compared to control values. However, exposure to CB or DBT reduced in ovo EROD activity in embryos coexposed to BNF. Carbazole and DBT were characterized in vitro as noncompetitive CYP1A inhibitors. Carbazole and DBT enhanced the embryotoxicity of BNF, although neither compound was embryotoxic by itself. The co-occurrence of CB and DBT with PAH-type AHR inducers in contaminated ecosystems may increase the toxicity of PAH-type AHR agonists in these settings and may need to be considered when estimating the embryotoxicity of PAH mixtures.
Correlation analyses for bimolecular nucleophilic substitution reactions of chloroacetanilide herbicides and their structural analogs with environmentally relevant nucleophiles
Authors: Lippa Katrice A. , Roberts A. Lynn
Published: October 2005

Second-order rate constants (kNuc) for aqueous-phase bimolecular nucleophilic substitution (SN2) reactions of a range of anionic nucleophiles with alachlor, propachlor, and two analogs of propachlor (a thioacetanilide and a β-anilide) were fit to the Swain-Scott and Edwards models. Correlations of literature kNuc values for analogous reactions of methyl chloride and methyl benzenesulfonate were included for comparison. The Swain-Scott correlation yielded poor to fair results for chloroacetanilides and their analogs, with adjusted (adj) r2 values ranging from 0.67 to 0.89, which are comparable to correlations for CH3Cl and CH3OSO2Ph (r2 (adj) = 0.80 and 0.85, respectively). Both the one- and two-parameter Edwards models yielded improved correlations for the majority of substrates. A pronounced dependence on the substrate polarizability (α) factor generally was observed for the Edwards model, with a negligible dependence on the substrate basicity (β) factor. Substrate polarizability factors for the one-parameter Edwards model were significantly larger for alachlor, propachlor, and the β-anilide analog of propachlor than for methyl chloride and methyl benzenesulfonate. This indicates that the chloroacetanilides are activated toward SN2 reactions with highly reactive nucleophiles (e.g., HS−, PhS−, and S2-n) relative to other saturated carbon substrates. At best, the Swain-Scott and Edwards models only furnish order-of-magnitude predictions of kNuc for the substrates investigated.
Application of frog embryo teratogenesis assay-Xenopus to ecological risk assessment
Authors: Hoke Robert A. , Ankley Gerald T.
Published: October 2005

An expert workshop recently was convened to consider the frog embryo teratogenesis assay-Xenopus (FETAX) as a screening method for identifying the potential developmental toxicity of single chemicals and chemical mixtures. One recommendation from the workshop was that, in order to determine the utility of FETAX for ecological risk assessments, additional consideration of how the assay is conducted is necessary. In addition, a comparative evaluation would be useful of FETAX endpoints (i.e., survival, malformations, growth) versus each other, endpoints from aquatic toxicity tests using more commonly tested species of cladocerans and fish, and tests with other amphibian species. This review provides an evaluation and critique of the current FETAX protocol from two perspectives: Practical considerations relative to conducting the test and sensitivity of the assay (and associated endpoints) compared to tests with other species. Several aspects of the current standard protocol, including test temperature, diet, loading rates, and chemical exposure options, need to be modified to ensure that the assay is robust technically. Evaluation of FETAX data from the open literature indicates that growth is the most sensitive endpoint in the assay, followed by malformations and then survival; unfortunately, the growth endpoint often is not considered or reported in the assay. Comparison of FETAX data with acute toxicity data from tests with other amphibians or traditional aquatic test species indicates FETAX is relatively insensitive. This suggests that environmental risk assessments using acute hazard data from tests with traditional aquatic test species usually would be more protective of native amphibian species than risk assessments that use hazard data from FETAX.
Validation of otolith growth rate analysis using cadmium-exposed larval topsmelt (Atherinops affinis)
Authors: Rose Wendy L. , Hobbs James A. , Nisbet Roger M. , Green Peter G. , Cherr Gary N. , Anderson Susan L.
Published: October 2005

We applied otolith growth rate analysis to an investigation of cadmium (Cd)-exposed larval topsmelt (Atherinops affinis) to determine if growth rate was a more sensitive measure than somatic growth (body wt or length). Topsmelt otoliths, calcareous concretions in the fish inner ear, formed daily increments, and otolith growth was proportional to somatic growth. Nine-day posthatch larval topsmelt were exposed to Cd (0–100 ppb) in seawater for 14 d and fed low or high ration levels in separate experiments. Whereas Cd impaired topsmelt growth and growth rates, the extent of growth reduction was dependent on the ration level. At high ration levels, otolith and somatic growth rates of fish exposed to Cd (50 and 100 ppb) were significantly reduced; however, no differences in final mean weight and only marginal differences in final mean length of Cd-exposed topsmelt were observed. At low ration levels, we detected reductions in both somatic growth as well as otolith and somatic growth rates of topsmelt exposed to Cd (50 and 100 ppb). Otolith growth rate analysis was more sensitive than growth measurements of Cd-exposed topsmelt, because it allowed the detection of small differences in growth rates even when differences in somatic growth were not observed.
Effects of polychlorinated biphenyls on the schooling behavior of Japanese medaka (Oryzias latipes)
Authors: Nakayama Kei , Oshima Yuji , Hiramatsu Kazuaki , Shimasaki Yohei , Honjo Tsuneo
Published: October 2005

The effects of polychlorinated biphenyls (PCBs; Kanechlor 400) on the schooling behavior of Japanese medaka (Oryzias latipes) were tested after feeding with various concentrations of PCBs (0, 1, 5, 25, and 125 μg/g). To test schooling, three PCB-exposed medaka and three untreated fish were placed in one chamber, and their swimming trajectories were recorded. Swimming velocity, turning angle, and nearest-neighbor distance (NND) were analyzed individually, and the polarization and expanse of each schooling group were analyzed. Fractal dimension analysis was performed for trajectory, swimming velocity, and turning angle. Six behaviors (school formed by six swimming medaka, school formed by six stationary medaka, school formed by three to five swimming medaka, school formed by three to five stationary medaka, swimming without schooling, and stationary without schooling) were quantified with time. Behavioral parameters were the same for PCB-exposed and unexposed medaka in the same schooling group. Swimming velocity decreased in a dose-dependent manner, and NND in the group exposed to 25 μg/g of PCBs was significantly longer (126%) than that in the controls. The fractal dimensions of trajectory and turning angle increased significantly in the highest PCB-exposure group, indicating that schools containing PCB-exposed individuals frequently changed direction. The PCBs shortened the time of school formed by six swimming fish, which was 23.7% of the control value in the group exposed to 25 μg/g of PCBs. The frequency of collisions between individuals was significantly greater in the highest-exposure group (31.3) than in the controls (13.3). Thus, PCB exposure influences the behavior of unexposed fish in the same school, consequently affecting schooling behavior.
Analysis of estrogenic effects by quantification of green fluorescent protein in juvenile fish of a transgenic medaka
Authors: Scholz Stefan , Kurauchi Kanta , Kinoshita Masato , Oshima Yuji , Ozato Kenjiro , Schirmer Kristin , Wakamatsu Yuko
Published: October 2005

The ChgH-GFP strain of the teleost medaka containsa regulatory region of the estrogen-responsive choriogenin H (chgH) gene fused to the green fluorescent protein (GFP) gene. The strain was developed for the identification of environmental estrogens by noninvasive analysis of GFP fluorescence. In the present study, a quantification method for GFP by image analysis was established and applied to the analysis of time-anmd d concentration-dependent GFP fluorescence in juvenile fish. Concentration-response analyses were performed with fish exposed for 14 d to 17β-estradiol (0.37–367 pM), genistein (0.37–367 nM), or p-nonylphenol (0.367–1,835 nM). By means of image analysis, it was shown that ChgH-GFP was induced at 183.5 pM or greater 17β-estradiol. Time-course and recovery experiments indicated a strong accumulation of GFP in the liver. Results of reverse transcriptase-polymerase chain reaction analysis of choriogenin H and vitellogenin demonstrated induction of gene expression for the same range of concentrations as that for GFP analysis. Neither expression of these genes nor GFP fluorescence was induced by genistein and p-nonylphenol. Although the ChgH-GFP strain failed to detect these weakly estrogenic compounds, the simplicity of the GFP quantification during early life stages of fish offers promising possibilities for further developments of transgenic strains using different target regulatory sequences.
Evaluation of microbial inoculation and vegetation to enhance the dissipation of atrazine and metolachlor in soil
Authors: Zhao Shaohan , Arthur Ellen L. , Moorman Thomas B. , Coats Joel R.
Published: October 2005

Four greenhouse studies were conducted to evaluate the effects of native prairie grasses and two pesticide-degrading bacteria to remediate atrazine and metolachlor in soils from agricultural dealerships (Alpha site soil, northwest Iowa, USA; Bravo site soil, central Iowa, USA). The Alpha soil contained a low population of atrazine-degrading microorganisms relative to the Bravo soil. Each soil freshly treated with atrazine or metolachlor was aged for a short or long period of time, respectively. An atrazine-degrading bacterium, Agrobacterium radiobacter strain J14a; a metolachlor-degrading bacterium, Pseudomonas fluorescens strain UA5–40; and a mixture of three native prairie grasses—big bluestem (Andropogon gerardii Vitman), yellow Indian grass (Sorghastrum nutans [L.] Nash), and switchgrass (Panicum virgatum L.)—were added to the soils after the soils were aged for long periods of time. The soils aged for short periods of time were treated with J14a, the prairie grasses, or both after aging. The J14a and the grasses significantly reduced the concentration of atrazine in Alpha soil when the soil was aged for a short period of time. However, these treatments had no statistically significant effect when the soil was aged for a long period of time or on atrazine in Bravo soil. Inoculation with UA5–40 did not enhance metolachlor dissipation in either soil, but vegetation did increase metolachlor dissipation. Our results indicate that the dissipation of atrazine by J14a is affected by the presence of indigenous atrazine-mineralizing microorganisms and probably by the bioavailability of atrazine in the soil.
Toxicity, biotransformation, and mode of action of arsenic in two freshwater microalgae (Chlorella sp. and Monoraphidium arcuatum)
Authors: Levy Jacqueline L. , Stauber Jennifer L. , Adams Merrin S. , Maher William A. , Kirby Jason K. , Jolley Dianne F.
Published: October 2005

The toxicity of As(V) and As(III) to two axenic topical freshwater microalgae, Chlorella sp. and Monoraphidium arcuatum, was determined using 72-h growth rate—inhibition bioassays. Both organisms were tolerant to As(III) (72-h concentration to cause 50% inhibition of growth rate [IC50], of 25 and 15 mg As[III]/L, respectively). Chlorella sp. also was tolerant to As(V) with no effect on growth rate over 72 h at concentrations up to 0.8 mg/L (72-h IC50 of 25 mg As[V]/L). Monoraphidium arcuatum was more sensitive to As(V) (72-h IC50 of 0.25 mg As[V]/L). An increase in phosphate in the growth medium (0.15–1.5 mg PO3-4/L) decreased toxicity, i.e., the 72-h IC50 value for M. arcuatum increased from 0.25 mg As(V)/L to 4.5 mg As(V)/L, while extracellular As and intracellular As decreased, indicating competition between arsenate and phosphate for cellular uptake. Both microalgae reduced As(V) to As(III) in the cell, with further biological transformation to methylated species (monomethyl arsonic acid and dimethyl arsinic acid) and phosphate arsenoriboside. Less than 0.01% of added As(V) was incorporated into algal cells, suggesting that bioaccumulation and subsequent methylation was not the primary mode of detoxification. When exposed to As(V), both species reduced As(V) to As(III); however, only M. arcuatum excreted As(III) into solution. Intracellular arsenic reduction may be coupled to thiol oxidation in both species. Arsenic toxicity most likely was due to arsenite accumulation in the cell, when the ability to excrete and/or methylate arsenite was overwhelmed at high arsenic concentrations. Arsenite may bind to intracellular thiols, such as glutathione, potentially disrupting the ratio of reduced to oxidized glutathione and, consequently, inhibiting cell division.
Electron paramagnetic resonance analysis of the distribution of a hydrophobic spin probe in suspensions of humic acids, hectorite, and aluminum hydroxide-humate-hectorite complexes
Authors: Spagnuolo Matteo , Jacobson Astrid R. , Baveye Philippe
Published: October 2005

Until recently, there were no techniques capable of direct observation of the microscale locations where nonpolar organic compounds accumulate when associated with natural geosorbents. The ability of electron paramagnetic resonance (EPR) spectroscopy to monitor and elucidate directly the different molecular-scale environments of paramagnetic spin probes has been demonstrated lately in model soils, yet it remains untested in complex systems. In this general context, the present investigation was aimed at assessing the extent to which EPR could be used to monitor the sorption of 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy benzoate (TEMPO benzoate), a hydrophobic spin probe, on a smectite (hectorite), two humic acids, and their complexes in the presence or absence of aluminum hydroxide. Results demonstrate that EPR is able to monitor easily adsorption on these sorbents in batch-style experiments. Distribution coefficient (Kd) values of 455.4 and 483.1 ml/g were found for the adsorption of TEMPO benzoate on hectorite-humic acids complexes, compared to respective Kd values of 46 and 147 ml/g predicted solely on the basis of the mass of humic acids present in the complexes. These observations confirm the significant role of hectorite for the sorption of hydrophobic compounds, together with humic acids, contrary to common belief that emphasizes the almost exclusive sorptive role of organic matter. In addition, for the first time, EPR is able to provide evidence that hydrophobic molecules in the presence of geosorbents can segregate in multimolecular clusters that are in equilibrium with aqueous probe concentrations below the probe's solubility threshold. Possible consequences of this clustering process in terms of the fate and transport of hydrophobic compounds in subsurface environments are discussed.
Persistent organic pollutants in the diet of harbor seals (Phoca vitulina) inhabiting puget sound, washington (USA), and the strait of Georgia, British Columbia (Canada): A food basket approach
Authors: Cullon Donna L. , Jeffries Steven J. , Ross Peter S.
Published: October 2005

Harbor seals (Phoca vitulina) inhabiting Puget Sound (WA, USA) recently were found to be seven times more contaminated with polychlorinated biphenyls (PCBs) than those inhabiting the adjacent Strait of Georgia (BC, Canada). We carried out a food basket approach to approximate realistic dietary exposures of both new (e.g., polybrominated diphenyl ethers [PBDEs]) and legacy (e.g., dichlorodiphenyltrichloroethane [DDT]) persistent organic pollutants (POPs) for these harbor seals. Food basket homogenates, each consisting of over 200 individual prey items, were constructed using documented dietary preferences for harbor seals in these basins, and analyzed for organochlorine pesticides, flame retardants, and other persistent contaminants. Concentration rankings for the major contaminant classes in the Puget Sound food basket were sumPCBs > sumPBDEs > sumDDT, and for the Strait of Georgia food basket were sumPCBs > sumDDT > sumPBDEs, highlighting the emergence of PBDEs as a significant concern in the regional environment. Consistent with observations in harbor seals, PCB concentrations in the Puget Sound food basket were seven times higher than in its Strait of Georgia counterpart. Based on our food basket results, the estimated daily intake of sumPCB toxic equivalents to dioxin by Puget Sound harbor seals exceeds some wildlife consumption guidelines for PCBs. Our results indicate that both legacy and new POPs present a health risk to these marine mammals.
Effects of maternally transferred organochlorine contaminants on early life survival in a freshwater fish
Authors: Johnston Thomas A. , Miller Loren M. , Whittle D. Michael , Brown Scott B. , Wiegand Murray D. , Kapuscinski Anne R. , Leggetta William C.
Published: October 2005

Laboratory research has shown that female fish can pass toxic organochlorines (OCs) from their bodies to their eggs, killing their offspring if sufficient quantities are transferred. We conducted a controlled incubation study using gametes from a wild, OC-contaminated walleye (Sander vitreus) population (Bay of Quinte, Lake Ontario, Canada) in order to assess among-female variation in offspring early life survival in relation to ova concentrations of planar OCs (polychlorinated dibenzo-p-dioxins and furans and planar polychlorinated biphenyls) and a suite of other maternal and ova characteristics. Equal volumes of ova from each female were fertilized, pooled, and incubated together as an experimental cohort. Relative survival of each female's offspring was estimated as the proportion of surviving larvae (at ∼5 d posthatch) that she contributed to the cohort as determined by microsatellite DNA parentage assignment. Total planar OC concentration (expressed as toxic equivalency of 2,3,7,8-tetrachloro-dibenzo-p-dioxin) of ova was positively related to maternal age and size and to ova lipid content. However, early life survival did not decline with increasing ova planar OC concentrations. Similarly, we observed no significant relationships between early life survival and ova thiamine content, ova fatty acid composition, or maternal age or size. Early life survival was more strongly correlated with date of spawn collection, thyroid hormone status of the ova, and ovum size. Maternally transferred planar OCs do not appear to negatively influence female reproductive success in this walleye population.
Complex mixture toxicity for single and multiple species: Proposed methodologies
Authors: de Zwart Dick , Posthuma Leo
Published: October 2005

Methods for the assessment of ecological risks associated with exposure to defined mixtures of toxicants are reviewed and formalized for single-species toxicity. Depending on the modes of action of toxicants in a mixture, these methods apply either the model for concentration additivity (CA) or the model for response additivity (RA). For complex mixtures, the present paper advocates the use of a new, two-step, mixed-model approach as a logical extension of model selection: Mixture toxicity for individual modes of action is evaluated with the CA model, and the toxicities of different modes of action are combined using the RA model. Using comparable mixture toxicity strategies in combination with the concept of species-sensitivity distributions, we develop a method to address and predict the risk for direct effects on the composition of species assemblages and biodiversity. The data needed for modeling can be obtained from existing databases, and lack of data can, in part, be addressed by the use of toxicity patterns in those databases. Both single- and multiple-species methods of mixture risk prediction are useful for risk management, because they allow ranking of polluted sites and affected species as well as identification of the most hazardous contaminants, at least in a comparative way. Validation of the proposed methods is feasible but currently limited because of a lack of appropriate data.
1,3-dinitrobenzene toxicity in the least shrew, Cryptotis parva
Authors: Mock Orin B. , Casteel Stan W. , Darmani Nissar A. , Shaddy James H. , Besch-Williford Cynthia , Towns Lex C.
Published: October 2005

Shrews are abundant in most areas of toxic chemical contamination and bioaccumulate pollutants at much higher rates than sympatric rodent species. As a part of studies to provide information concerning the toxicity of 1,3-dinitrobenzene (DNB) in least shrews (Cryptotis parva), groups of 10 females and 10 males received DNB at O (control), 0.7, 2.9, 11.6, and 46.3 μl/L (equivalent mean daily dosage of 0, 0.26, 1.06, 4.26, and 17.0 mg/kg body wt in each sex) in their diet for 14 d. Leukocytosis present at the 0.26 mg/kg body weight/d dosage established the lowest-observed-adverse effect level (LOAEL). Adrenal enlargement was noted at the 1.06 mg/kg body weight/d level. Splenic enlargement and reductions in hematocrit and hemoglobin values occurred at the 4.26 mg/kg body weight/d treatment. Enlargements in the liver and heart and reductions in brown fat weight, granulocyte numbers, and alanine aminotransferase levels were present at high dose levels. Histopathologic examinations showed Kupffer's cell hemosiderosis and suggested testicular damage at the two highest tested doses but failed to confirm brain lesions. Least shrews do not follow standard scaling estimates for lifespan or metabolic rates. The LOAEL calculated from the standard terrestrial screening benchmark equation was higher than our findings, suggesting that these estimates must be viewed with caution.
Comparison of Cd, Cu, and Zn toxic effects on four marine phytoplankton by pulse-amplitude-modulated fluorometry
Authors: Miao Ai-Jun , Wang Wen-Xiong , Juneau Philippe
Published: October 2005

The toxic effects of Cd, Cu, and Zn on four different marine phytoplankton, Dunaliella tertiolecta, Prorocentrum minimum, Synechococcus sp., and Thalassiosira weissflogii, were examined by comparing the cell-specific growth rate, pulse-amplitude-modulated (PAM) parameters (maximum photosystem II quantum yield ϕM and operational quantum yield ϕ'M), chlorophyll a content, and cellular metal concentration, over a 96-h period. The calculated no-observed-effect concentration (NOEC) based on both cell-specific growth rate and two PAM parameters (ϕM and ϕ'M) were mostly identical. Thus, these PAM parameters and cell-specific growth rate were comparable in their sensitivities as the biomarkers for trace metal toxicity to marine phytoplankton. The cyanobacteria Synechococcus sp. was the most sensitive species among the four algal species tested because of its higher cell surface to volume ratio. The toxicity of the three tested metals followed the order of Cd > Cu > Zn based on the cellular metal concentration of the four algae at the NOEC. The cellular metal bioaccumulation followed the same Freundlich isotherm for each metal regardless of the algal species, indicating that the metal accumulation was a nonmetabolic process under high ambient metal concentrations and that the cell surface metal binding was comparable among the different species. For all the algae examined in our study, the bioaccumulation potentials of Cu and Zn were similar to each other, while the Cd bioaccumulation was much lower under environmentally realistic metal concentration.