bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selected trace elements and organochlorines: Some findings in blood and eggs of nesting common eiders (Somateria mollissima) from Finland
Authors: Franson J Christian , Hollmen Tuula , Poppenga Robert H , Hario Martti , Kilpi Mikael , Smith Milton R 
Published: March 2010

Abstract
In 1997 and 1998, we collected blood samples from nesting adult female commoneiders (Somateria mollissima) at five locations in the Baltic Sea near coastal Finland and analyzed them for lead, selenium, mercury, and arsenic. Eggs were collected from three locations in 1997 for analysis of selenium, mercury, arsenic, and 17 organochlorines (OCs). Mean blood lead concentrations varied by location and year and ranged from 0.02 ppm (residues in blood on wet weight basis) to 0.12 ppm, although one bird had 14.2 ppm lead in its blood. Lead residues in the blood of eiders were positively correlated with the stage of incubation, and lead inhibited the activity of the enzyme delta-aminolevulinic acid dehydratase (ALAD) in the blood. Selenium concentrations in eider blood varied by location, with means of 1.26 to 2.86 ppm. Median residues of selenium and mercury in eider eggs were 0.55 and 0.10 ppm (residues in eggs on fresh weight basis), respectively, and concentrations of both selenium and mercury in eggs were correlated with those in blood. Median concentrations of p,p′-dichlorodiphenyldichloroethylene in eggs ranged from 13.1 to 29.6 ppb, but all other OCs were below detection limits. The residues of contaminants that we found in eggs were below concentrations generally considered to affect avian reproduction. The negative correlation of ALAD activity with blood lead concentrations is evidence of an adverse physiological effect of lead exposure in this population.
Heavy metal toxicity and genotoxicity in water and sewage determined by microbiological methods
Authors: Codina Juan C , Cazorla Francisco M , Pérez-García Alejandro , de Vicente Antonio 
Published: March 2010

Abstract
Acute toxicity and genotoxicity of cadmium, copper, chromium, mercury, nickel, and zinc dissolved in deionized water and in sewage were established by comparing the EC50 and EC20 values obtained by different microbial assays. For acute toxicity determination, The Netherlands Standard NEN6509 test, the spectrophotometric assays of respiratory inhibition using Saccharomyces cerevisiae and Pseudomonas fluorescens, and the Microtox® test were employed. To determine metal genotoxicity, the Salmonella typhimurium and Escherichia coli mutagenicity tests, the SOS-β-galactosidase genotoxicity test, and the Mutatox™ assay were used. The toxicity of the different assayed metals varied from the most toxic, mercury, to the least toxic, nickel and zinc. Two different rankings of toxicity and genotoxicity, very similar to each other, were established. The toxicity ranking was Hg &gt; Cr &gt; Cd ∼ Cu ∼ Zn &gt; Ni, and the genotoxicity ranking was Hg &gt; Cr &gt; Cu ∼ Cd ∼ Ni &gt; Zn. The association between the toxicity and genotoxicity of copper and chromium in the dissolved and suspended fractions of sewage was also determined. Copper was mainly associated with the suspended fractions and chromium with the dissolved fractions of sewage.
Estrogenicity of alkylphenolic compounds: A 3-D structure—activity evaluation of gene activation
Authors: Schmieder Patricia K , Aptula Aynur O , Routledge Edwin J , Sumpter John P , Mekenyan Ovanes G 
Published: March 2010

Abstract
A structure–activity relationship evaluation of alkylphenol activation of a human estrogen receptor (hER) reporter gene construct was done using the Common Reactivity Pattern approach. Energetically reasonable conformer distributions for selected steric and electronic chemical descriptors were presented and analyzed. Comparisons of descriptor distributions across active and nonactive chemicals allowed determination of a common reactivity pattern for hER activation. Chemicals capable of hER binding and gene transcription have high density of O–C{sp3}distances, from 6.2 to 6.5 Å; maximum distances between atoms in the molecule, ranging from 9.9 to 10.1 Å; and a population density on the lowest unoccupied molecular orbital for O-atoms from 0.09 to 0.12 AU. Alkylphenols that were nonactive in the recombinant yeast cell assay lacked these stereoelectronic requirements, presumably precluding receptor occupancy or necessary estrogen response element interaction. Derived reactivity patterns were successfully coded into decision trees used to screen additional alkylphenols for potential hER activation. Successful structure–activity relationship modeling and prediction of gene activation for 26 of 29 alkylphenols is an additional step in the elucidation of chemical steric and electronic three-dimensional parameters that predict which xenobiotics are likely to be estrogenic and demonstrates a valuable tool for screening and prioritization of chemicals for further testing.
Metabolic responses to acute toxicity of alkylphenols and alkylphenol polyethoxylates in Elliptio complanata measured by calorespirometry
Authors: Levine Catherine , Cheney Marcos A 
Published: March 2010

Abstract
Alkylphenol ethoxylates (APEs) are important contaminants of world water systems with effects on aquatic life. Metabolic responses to short-term acute toxicities of alkylphenol and alkylphenolethoxylates were investigated in the freshwater bivalve mollusk Elliptio complanata using isothermal batch microcalorimetry and respirometry. Metabolic heat rates were altered following short-time exposure of the gill tissue to these compounds over the concentration range of 10−6 to 10−3 M. There was a time and concentration dependence of the effects of alkylphenol and alkylphenolethoxylates on metabolic heat rates. In general, treatment with alkylphenols and alkylphenolethoxylates at concentrations ranging from 10−6 to 10−4 M caused stimulation of metabolic heat rates, possibly due to uncoupling of oxidative metabolism. Higher concentrations subsequently caused inhibition of metabolic activity and thus decreased heat rates. Rates of oxygen consumption by the gill tissue exposed to the surfactants, as a measure of effects on electron flux through mitochondria, showed a similar pattern of respiratory rate stimulation at low concentration and inhibition at higher concentration. Therefore, the batch calorespirometric method proved to be a useful technique to assess the toxicity of a group of surfactants on the control of energy flux in gills of a freshwater bivalve mollusk.
Effect of bisphenol a on the early life stage in Japanese medaka (Oryzias latipes)
Authors: Yokota Hirofumi , Tsuruda Yukinari , Maeda Masanobu , Oshima Yuji , Tadokoro Hiroshi , Nakazono Akinobu , Honjo Tsuneo , Kobayashi Kunio 
Published: March 2010

Abstract
Japanese medaka (Oryzias latipes) were exposed to bisphenol A (BPA) at the sublethal concentrations of 2.28, 13.0, 71.2, 355, and 1,820 μg/L (as mean measured concentrations) in the early life stage from fertilized eggs to 60-d posthatch. Except for the growth and sexual differentiation of the fish at 60-d posthatch, no effects were observed on hatching success and time to hatching in embryological stage and on mortality and abnormal behavior and appearance in hatched larvae. The growth of the fish was suppressed with increasing BPA concentrations, resulting in significant differences in both the total length and body weight of medaka at 1,820 μg/L compared with the controls. When observed for their external secondary sex characteristics, no males were identified in the 1,820-μg/L treatment. In addition, histological examination showed that 32% of fish in the 1,820-μg/L group had testis-ova composed of both testicular germ cells and oocytes. Consequently, the lowest effective concentration for the early life stage of medaka was between 355 and 1,820 μg/L. Since the environmental concentrations of BPA are usually three orders lower than the lowest effective concentration, BPA alone may not affect the early life stage of wild fish populations.
Transgenic strains of the nematode Caenorhabditis elegans as biomonitors of metal contamination
Authors: Cioci L K. , Qiu Ling , Freedman Jonathan H. 
Published: March 2010

Abstract
Transition metal contamination poses a serious environmental and human health threat. The bioavailability of transition metals in environmental samples can best be assessed with living organisms. A transgenic strain of the free-living soil nematode Caenorhabditis elegans has been engineered for monitoring the bioavailability of metals. A reporter transgene consisting of a fragment of the promoter from the C. elegans metallothionein-2 gene (mtl-2) that controls the transcription of a β-galactosidase reporter (lacZ) has been integrated into the genome of this organism. By using these transgenic C. elegans, the toxicological response to metals in samples can be quickly measured with a simple histochemical staining assay. The C. elegans that contain the mtl-2:lacZ transgene provide a more sensitive assay of exposure to cadmium, mercury, zinc, and nickel than 24-h LC50 assays or those using nematodes with heat-shock protein–based reporter transgenes. This study demonstrates that C. elegans that contain mtl-2:lacZ transgenes can function as sensitive toxicological indicators of metals.
Environmental risk limits for polychlorinated biphenyls in the Netherlands: Derivation with probabilistic food chain modeling
Authors: van Wezel Annemarie P , Traas Theo P , van der Weiden Martine E J , Crommentuijn Trudie H , Sijm Dick T. H M 
Published: March 2010

AbstractEnvironmental risk limits (ERLs) for individual congeners of polychlorinated biphenyls (PCB 77, 105, 118, 126, 153, 156, 157, and 169) are derived. After lipid normalization, toxicity data for birds, mammals, and aquatic organisms were converted to equivalent concentrations in soil or sediment organic carbon (OC). Accumulation in the food chain was taken into account. Field-derived data on the environmental fate of PCBs, e.g., biomagnification factors and biota-to-sediment accumulation factors, were used in the calculations. The variability in these data was incorporated by using probabilistic techniques. Parameters that are difficult to measure for these hydrophobic compounds, such as the bioconcentration factor or the sediment/water partition coefficient, were avoided where possible. Probability distributions for various species were combined per congener when statistically appropriate; ERLs were based on the fifth percentile of these combined distributions. Congener patterns occurring in various sediments and invertebrates in The Netherlands were used for determining a mixture ERL for non- and mono-ortho PCBs. The PCB 118 was selected as a guiding congener. If the concentration of PCB 118 is less than 5 μg/kg OC, Dutch ecosystems are assumed to be protected for effects of the whole mixture of non- and mono-ortho-substituted PCBs. Concentrations associated with adverse effects in field studies were comparable to concentrations that would result if all congeners would be present at the ERL level.
Assessment of 2,4,6-trinitrotoluene toxicity in field soils by pollution-induced community tolerance, denaturing gradient gel electrophoresis, and seed germination assay
Authors: Siciliano Steven D , Gong Ping , Sunahara Geoffrey I , Greer Charles W 
Published: March 2010

AbstractDetermining the toxicity of contaminants to soil organisms under field conditions is hampered by site-specific and temporal factors that modulate contaminant availability. Assessing the pollution-induced community tolerance (PICT) of indigenous microbial communities integrates these complex environmental factors. The purpose of this study was to determine if the PICT response was proportional to 2,4,6-trinitrotoluene (TNT) concentrations in soil, if changes detected by PICT were also evident in soil microbial community composition, and if the PICT response correlated with phytotoxicity assays. Microorganisms extracted from TNT-contaminated field soils were mixed with a solution containing six different concentrations of TNT and inoculated into Biolog ECO plates. The utilization rate of substrates was determined over a 7-d period. Denaturing gradient gel electrophoretic analysis of a portion of the gene encoding 16S rDNA described the structure of the soil microbial community. Phytoindicators (Poa compressa and P. palustris L.) of TNT pollution were identified and used to assess TNT phytotoxicity in soil samples. The TNT (in Biolog wells) greatly inhibited microbial communities from locations with low in situ TNT exposure. The inhibition of microbial use of L-asparagine, L-phenylalanine, and D-glucosaminic acid by TNT (in Biolog wells) increased as TNT concentration in soil decreased. Locations differing in ECO-PICT response also differed in their microbial community composition and TNT phytotoxicity. Decreased phytotoxicity of field soils corresponded to decreases in PICT. The results from this study indicated that ECO-PICT is an effective assay to rapidly detect TNT exposure and toxicity in soil microbial communities.
Prediction of population-level response from mysid toxicity test data using population modeling techniques
Authors: Kuhn Anne , Munns Wayne R , Poucher Sherry , Champlin Denise , Lussier Suzanne 
Published: March 2010

AbstractAcute and chronic bioassay statistics are used to evaluate the toxicity and risks of chemical stressors to the mysid shrimp Americamysis bahia (formerly Mysidopsis bahia). These include LC50 values from acute tests, chronic values (the geometric mean of the no-observed-effect concentration and the lowest-observed-effect concentration from 7-d and life-cycle tests), and U.S. Environmental Protection Agency water quality criterion continuous concentration (CCC). Because these statistics are generated from responses of individual organisms, the relationships of these statistics to significant effects at higher levels of ecological organization are unknown. This study was conducted to evaluate the quantitative relationships between toxicity test statistics and a concentration-based statistic derived from exposure–response models relating projected population growth rate to stressor concentration. This statistic, C*, describes the concentration above which mysid populations are projected to decline in abundance as determined using population modeling techniques. An analysis of responses of A. bahia to 10 metals, nine organic compounds, and ammonia surprisingly indicated the acute LC50 to be the best predictor of C*, followed by the chronic value from life-cycle tests, which predicted population-level response almost equally as well. The chronic value for the 7-d test was less predictive of population-level effects. The CCC was lower than C* for 94% of the compounds evaluated, indicating the criterion value to be protective of population-level effects for A. bahia, as intended.
Factors affecting the release of hydrophobic organic contaminants from natural sediments
Authors: Chen Wei , Kan Amy T , Fu Gongmin , Tomson Mason B 
Published: March 2010

AbstractNumerous physical and chemical changes in aquatic systems can affect the sorption and desorption of organic contaminants. In this study, the effects of competitive sorption, caustic treatment, and temperature on the release of sorbed chlorinated hydrocarbons and naphthalene from natural sediments were studied. The experiments were specially designed so that the results would reflect the nature of the irreversible compartment. The effect of competitive sorption fell into two categories. The release of chlorinated benzenes and hexachlorobutadiene from the reversible fraction in Lake Charles, Louisiana, USA, sediment was increased with the competitive sorption of naphthalene, while the release of naphthalene and 1,4-dichlorobenzene from the irreversible compartments in Dickinson, Texas, USA, sediment was unaffected by the sorption of trans-cinnamic acid at 100 mg/L. Similarly, preliminary experiments showed that caustic treatment of sediments did not enhance the desorption from the irreversible fraction. Also, the enthalpy of sorption associated with the irreversible compartment was −21.60 ± 0.76 kJ/mol, indicating that sorption was via simple van der Waal's forces. Experimental results in this study support a previously proposed irreversible sorption mechanism in which irreversible sorption is attributed to the physical entrapment of organic molecules in sediment matrices after the hydrophobic partitioning.
Field study on desorption rates of polynuclear aromatic hydrocarbons from contaminated marine sediment
Authors: Zhang Yong , Wu Rudolf SS , Hong Hua-Sheng , Poon Ka-Fai , Lam Michael HW 
Published: March 2010

Abstract
The present study examines desorption kinetics of hydrophobic organic contaminants from sediment under conditions mimicking marine disposal. Trays of contaminated marine sediment were deployed in the subtidal zone of a pristine field site, and samples were taken at time intervals to study the desorption of acenaphthene, benzo[a]anthracene, benzo[b]fluoranthene, ben-zo[k]fluoranthene, benzo[a]pyrene, chrysene, fluoranthene, naphthalene, and phenanthrene over a period of 51 d. Results of the study indicated that 49.4 to 98.0% of the polycyclic aromatic hydrocarbons (PAHs) in the contaminated sediment were desorbed upon disposal in the coastal environment. The field desorption kinetics of these PAHs can be described by a two-compartment model. The measured slow desorption rate constants, k2, for acenaphthene, benzo[a]anthracene, benzo[b]fluoranthene, ben-zo[k]fluoranthene, benzo[a]pyrene, chrysene, fluoranthene, naphthalene, and phenanthrene were found to be 0.018, 0.061, 0.016, 0.028, 0.035, 0.021, 0.083, 0.031, and 0.080/d, respectively. Some of these data were in accordance with literature-reported values from laboratory desorption studies in which desorbed PAHs were directly extracted from the aqueous phase. However, they were at least an order of magnitude smaller than those obtained by conventional gas-stripping desorption techniques.
Survey of toxicity in ambient waters of the hudson/raritan estuary, USA: Importance of small-scale variations
Authors: Thursby Glen B , Stern Eric A , Scott K John , Heltshe James 
Published: March 2010

Abstract
This study was part of a characterization of the nature and severity of water-quality problems in the Hudson/Raritan Estuary in New York State and New Jersey, USA. The toxicity of ambient water was measured at 51 stations in the estuary by using standard tests with the sea urchin Arbacia punctulata and the marine red alga Champia parvula. Toxicity identification evaluations on samples from two stations suggested that cationic metals were the source of the observed toxicity. Overall results showed that toxicity could vary as much on the small scale, i.e., with depth and tide at a single site, as over several stations within a given subarea of the estuary. Thus, knowing about small-scale variations in toxicity is essential to understanding the significance of the variations from different areas or different sampling events.
Silver uptake by the green alga Chlamydomonas reinhardtii in relation to chemical speciation: Influence of chloride
Authors: Fortin Claude , Campbell Peter GC 
Published: March 2010

Abstract
Short-term (&lt;1 h) silver uptake by the green alga Chlamydomonas reinhardtii was measured in the laboratory in defined inorganic media over a range of silver and chloride concentrations. For a low, fixed, free Ag+ concentration (e.g., 8 nM), silver uptake increases markedly (up to ∼4×) as a function of the chloride concentration (5 μM→4 mM Cl−); the free-ion model would have predicted a constant silver uptake rate. No evidence could be found for the passive diffusion of the neutral AgCl0 complex or for the facilitated uptake of the anionic AgCl−2 complex. The enhanced uptake observed in the presence of chloride is related to the very high silver uptake rates demonstrated by the test alga, which lead to diffusion limitation in the boundary layer surrounding the algal cell. In such a situation, metal accumulation is proportional to the total metal concentration (i.e., to the concentration gradient between the bulk solution and the algal surface). At higher silver concentrations (e.g., ≥ 10−7 M), diffusion in the phycosphere is no longer rate limiting, the chloride stimulation disappears, and silver uptake is sensitive to the free-ion concentration. However, such a high concentration of silver is not likely to be encountered in the environment, even in wastewater effluents.
Derivation and application of relative potency estimates based on in vitro bioassay results
Authors: Villeneuve Daniel L , Blankenship Alan L , Giesy John P 
Published: March 2010

Abstract
Relative potency (REP) estimates are widely used to characterize and compare the potency of a wide variety of samples analyzed using in vitro bioassays. Relative potency estimates are generally calculated as a simple ratio: the EC50 of a well-characterized standard divided by the EC50 of a sample. Such estimates are valid only when the dose-response curves for the sample and standard are parallel and exhibit the same maximum achievable response (efficacy). These conditions are often either violated or cannot be demonstrated. As a result, there is a need to calculate and present REPs in a manner that addresses the potential uncertainties caused by violation of the assumptions of parallelism and equal efficacy. Multiple point estimates, over the range of responses from EC20 to EC80, can be used to derive relative potency ranges (REP20–80 range). The width of a REP20–80 range is directly proportional to the degree of deviation from parallelism between sample and standard dose-response curves. Thus, REP20–80 ranges both test the assumption of parallelism and characterize the amount of uncertainty in an REP estimate resulting from deviation from parallelism. Although uncertainties due to unequal efficacy cannot be easily characterized mathematically, a systematic method for evaluating sample efficacy has been developed into a framework to guide the derivation and application of REP estimates based on in vitro bioassay results. Use of the systematic framework and REP20–80 ranges was illustrated using three sample data sets. It is hoped that the framework and discussion presented will facilitate the use of bioassay-derived REP estimates to characterize samples of both known and unknown composition without ignoring the assumptions underlying REP estimation.
Inhibition-based biosensors for the detection of environmental contaminants: Determination of 2, 4-dichlorophenoxyacetic acid
Authors: Botrè Claudio , Botrè Francesco , Mazzei Franco , Podestà Elisabetta 
Published: March 2010

Abstract
In this work data are reported on the possibility for detection of environmental contaminants endowed with toxic effects by specifically designed electrochemical biosensors. A new bienzymatic inhibition biosensor based on the combined catalytic activity of the enzymes alkaline phosphatase and glucose oxidase is proposed and discussed for the direct determination of 2, 4-dichloro-phenoxyacetic acid (2, 4-D), one of the most powerful and diffused defoliants, which also is endowed with estrogenic properties. A discussion on the different approaches followed to manage the experimental data obtained by enzymatic inhibition biosensors is also presented.