bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incomplete ecdysis is an indicator of ecdysteroid exposure in Daphnia magna
Authors: Baldwin William S. , Bailey Robyn , Long Kristen E , Klaine Stephen 
Published: March 2010

Abstract
Daphnia magna were exposed for 21 d to the ecdysteroids, 20-hydroxyecdysone (20-E), the accepted molting hormone, and ponasterone A (PoA), an ecdysteroid found in some crustaceans and many plants. Daphnids were monitored for alterations in molting, fecundity, and survival time. The 20-E elicited no significant effects on molting frequency, and its significant effects on reproduction were only at concentrations (260 nM) associated with premature death caused by incomplete ecdysis. We also examined PoA, which has been reported to have 10× higher affinity for the ecdysone receptor than 20-E. Ponasterone A elicited effects similar to those of 20-E at approximately 10× lower concentrations. This suggests that affinity for the receptor is the major parameter determining activity in vitro and in vivo and that differences in metabolism and elimination in vivo were not significant. The effects of PoA on daphnids mimicked those of 20-E except PoA reduced fecundity in the second generation and 20-E had no effect. Last, both exogenous 20-E and PoA show similar effects, including premature death associated with incomplete ecdysis, and the overall difference in toxicity is mostly likely due to receptor affinity.
Soil—air exchange model of persistent pesticides in the United States cotton belt
Authors: Harner Tom , Bidleman Terry F , Jantunen Liisa M M , Mackay Don 
Published: March 2010

Abstract
Measurements of organochlorine pesticides (lindane, cis-chlordane [CC], trans-chlordane [TC], trans-nonachlor [TN]), dieldrin, p,p′-dichlorodiphenyldichloroethylene [DDE], and toxaphene) in Alabama, USA, air and soil were used to assess the soil-air equilibrium status and to identify compounds with significant contributions to observed air burdens. Of the compounds tested, p,p′-DDE and toxaphene showed a significant potential for outgasing, followed by dieldrin and trans-nonachlor, which showed moderate outgasing potentials. Lindane, cis-chlordane, and trans-chlordane were near soil-air equilibrium. A fugacity-based, multilayered soil-air exchange model was used to predict temporal trends of chemical in air and soil resulting from reemission of soil residues to a presumed clean atmosphere (maximum emission scenario). Results showed that p,p′-DDE and toxaphene accounted for up to 50% of the observed air burden and that approximately 200 to 600 kg of p,p′-DDE and 3,000 to 11,000 kg of toxaphene are released to the atmosphere each year by soils in Alabama (area = 1.23 × 1011 m2). High annual net fluxes were also predicted for dieldrin and trans-nonachlor (300–1,100 kg and 150–500 kg, respectively), but these only account for up to ∼20% of their observed air burdens.
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time
Authors: Elsgaard Lars , Petersen Søren O , Debosz Kasia 
Published: March 2010

Abstract
The anionic surfactant linear alkylbenzene sulfonate (LAS) may inhibit soil microorganisms and may occur in agricultural soil through the application of sewage sludge. For five microbial parameters (microbial biomass C and the potentials of iron reduction, ammonium oxidation, dehydrogenase activity, and arylsulfatase activity), we compared the effects of aqueous LAS and LAS-spiked sewage sludge added to existing levels of 0, 3, 8, 22, 62, 174, and 488 mg/kg soil (dry wt) in a Danish sandy agricultural soil that was incubated for 5 d to eight weeks. Arylsulfatase activity (measured after four weeks of incubation) was rather insensitive to LAS, with an EC10 of 222 and more than 488 mg/kg in soil samples treated with aqueous LAS and LAS-spiked sewage sludge, respectively. For the other microbial parameters, the short-term effects (approximately one to two weeks) of aqueous LAS were characterized by an EC10 in the range of 3 to 39 mg/kg. Application of LAS via sewage sludge generally reduced the short-term effects for the microbial parameters, and the EC10 for LAS in sludge-amended soil after approximately one to two weeks of incubation ranged from less than 8 to 102 mg/kg. Recovery potential was seen for most microbial parameters as a result of prolonged incubation, both under conditions of LAS persistence (anaerobic conditions, the iron-reduction test) and LAS depletion (aerobic incubations, all other assays). In conclusion, the short-term inhibitory effects of LAS on soil microbiology were decreased in the presence of sewage sludge and by a prolonged (two to eight weeks) laboratory incubation period.
Influences of aquatic plants on the fate of the pyrethroid insecticideLambida-cyhalothrin in aquatic environments
Authors: Hand Laurence H , Kuet Sui F , Lane Michael C G , Maund Stephen J , Warinton Jacqui S , Hill Ian R 
Published: March 2010

AbstractAquatic exposure assessments for pesticides are generally based on laboratory studies performed in water alone or water–sediment systems. Although aquatic macrophytes, which include a variety of bryophytes, macroalgae, and angiosperms, can be a significant component of many aquatic ecosystems, their impact on pesticide fate is generally not included in exposure assessments. To investigate the influence of aquatic plants on the fate and behavior of the pyrethroid insecticide lambda (Λ)-cyhalothrin, two laboratory experiments (to assess adsorption and degradation) and an indoor microcosm study (to assess fate under semirealistic conditions) were conducted. In the laboratory studies, adsorption to macrophytes was extensive and essentially irreversible, and degradation occurred rapidly by cleavage of the ester bond. In the indoor microcosm, which contained water, sediment, and macrophytes from a pond, degradation was also rapid, with DT50 and DT90 values of less than 3 and 19 h, respectively, for dissipation from the water column and of less than 3 and 56 h, respectively, for the whole system. For adsorptive and readily degraded pesticides like Λ-cyhalothrin, we conclude that macrophytes have considerable influence on fate and behavior in surface waters.
Toxicity of sediment-associated nitroaromatic and cyclonitramine compounds to benthic invertebrates
Authors: Lotufo Guilherme R , Farrar J. Daniel , Inouye Laura S , Bridges Todd S , Ringelberg David B 
Published: March 2010

Abstract
The toxicity of nitroaromatic (2,4-diaminonitrotoluene [2,4-DANT] and 1,3,5-trinitrobenzene [TNB]) and 14C-labeled cyclonitramine compounds (hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX] and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine [HMX]) to the marine polychaete Neanthes arenaceodentata and the estuarine amphipod Leptocheirus plumulosus following 10-or 28-d exposures to spiked sediments was investigated. Organismal-level effects on survival, growth, and reproduction and cellular-level effects on apoptosis (programmed cell death) were evaluated. Because cyclonitramines have low affinity for sediment, overlying water was not exchanged in the RDX and HMX exposures. Nitroaromatics sorbed strongly to sediment, resulting in near complete resistance to solvent extraction. Cyclonitramines sorbed weakly to sediment, as more 14C-activity was found in the overlying water than in the sediment at exposure termination. No significant decrease in survival or growth was observed with cyclonitramines at initial sediment concentrations as high as 1,000 μg/g. Survival was significantly affected by nitroaromatics at nominal sediment concentrations as low as 200 μg/g, with L. plumulosus being more sensitive than N. arenaceodentata. Growth was significantly decreased at sublethal concentrations of 2,4-DANT for N. arenaceodentata. Reproduction, measured only with L. plumulosus, was significantly decreased only in the highest RDX treatment and also in the lower TNB treatment. However, no decrease was observed in higher concentrations of TNB. Body burden at exposure termination was below detection limit (1 μg/kg) for all compounds. Significant inhibition of apoptosis was not accompanied by significant decreases in growth or reproduction. Because of its critical function in many biological processes, alterations in this endpoint may result in adverse effects on the organism and could be used as an early indicator of toxicity.
Toxicity evaluation of natural and synthetic phenanthrenes in aquatic systems
Authors: DellaGreca Marina , Fiorentino Antonio , Isidori Marina , Zarrelli Armando 
Published: March 2010

Abstract
Seven natural 9,10-dihydrophenanthrenes were isolated from the common reed Juncus effusus by means of chromatographic processes and identified by spectroscopic means. Furthermore, mimics of natural isolated compounds were synthesized to try to evaluate the influence of functional groups on the dihydrophenanthrene skeleton. Syntheses of compounds were based on the cross-coupling of 1-(2-iodo-5-methoxy)phenyl-ethanol with variously substituted iodobenzenes by zerovalent nickel. All the chemicals were tested to evaluate their effects on freshwater organisms from different trophic levels. Toxicity tests were performed on reducers (the bacterium Escherichia coli); producers (the alga Raphidocelis subcapitata, previously known as Selenastrum capricornutum); and consumers including a rotifer (Brachionus calyciflorus), a cladoceran (Daphnia pulex), and an anostracan (Thamnocephalus platyurus). Results suggested no one organism was uniquely sensitive to the chemicals tested. Toxicity depended on the kind and position of substituents on the aromatic skeleton.
Heavy metals in soft tissue of white-tailed eagles found dead or moribund in Germany and Austria from 1993 to 2000
Authors: Kenntner Norbert , Tataruch Frieda , Krone Oliver 
Published: March 2010

Abstract
Residues of the potentially toxic metals lead, mercury, and cadmium were analyzed in liver and kidney tissue of 61 free-ranging white-tailed eagles (Haliaeetus albicilla) found dead or moribund in Germany and Austria between 1993 and 2000. Highest values and the widest range were detected for lead in liver and for mercury in kidney tissue. Lead concentrations considered to induce lethal lead poisoning (&gt;5 ppm wet wt) were determined in 28% of liver samples. Lead fragments were detected in the gizzards of two specimens, presumably having died from lead intoxication. Histopathological findings in a recently dead white-tailed eagle indicating acute lead exposure comprise degenerative Purkinje cells in the cerebrellum and inclusion bodies in renal tubular cells. Mercury residues in organs are decreasing compared to former studies in periods when organomercury compounds were used as seed dressing. All cadmium values were low or are at background levels in white-tailed eagles. The present study clearly identifies lead as a toxic metal poison in white-tailed eagles in Germany and Austria.
Assessing acute and chronic copper risks to freshwater aquatic life using species sensitivity distributions for different taxonomic groups
Authors: Brix Kevin V , DeForest David K , Adams William J 
Published: March 2010

AbstractUsing copper as an example, we present a method for assessing chemical risks to an aquatic community using species sensitivity distributions (SSDs) for different taxonomic groups. This method fits probability models to chemical exposure and effects data to estimate the percentage of aquatic species potentially at risk and expands on existing probabilistic risk assessment methodologies. Due to a paucity of chronic toxicity data for many chemicals, this methodology typically uses an acute–chronic ratio (ACR) to estimate the chronic effects distribution from the acute effects distribution. We expanded on existing methods in two ways. First, copper SSDs were developed for different organism groups (e.g., insects, fish) that share similar sensitivities or ecological functions. Integration of exposure and effects distributions provides an estimate of which organism groups may be at risk. These results were then compared with a site-specific food web, allowing an estimation of whether key food web components are potentially at risk and whether the overall aquatic community may be at risk from the perspective of ecosystem function. Second, chronic SSDs were estimated using the relationship between copper ACRs and acute toxicity (i.e., the less acutely sensitive a species, the larger the ACR). This correction in the ACR removes concerns previously identified with use of the ACR and allows evaluation of a significantly expanded chronic data set with the same approach as that for assessing acute risks.
Model selection and parameterization of the concentration-response functions for population-level effects
Authors: Tanaka Yoshinari , Nakanishi Junko 
Published: March 2010

Abstract
As concentration–response functions for chronic population-level effects of pollutant chemicals, three mathematical models were presented and examined for goodness of fit to published toxicological data that estimated the population-level effects of chemicals in terms of the intrinsic rate of population growth (r). Among the examined concentration–r functions, the power function model, that is, r(x) = r(0)[1 – (x/a)β], in which x is the exposure concentration and α and β are parameters, performed with the best fit to each data set. The power function model is characterized by two parameters representing the absolute value of toxicity, α, and the curvature of responses, β. The bootstrap simulation, conducted on the entire data set consisting of all published data that we collected, indicated that the observed variance of β among actual data sets could be mostly explained by the random error variation generated from the bootstrap resamplings. The generic β value, determined from the entire data set and expected to denote the best estimate of β if the variability of β was completely due to random sampling error, was estimated as 1.84. It was implied that the response of the intrinsic rate of natural increase (r) to chemical exposure was nearly quadratic in many cases.
Modeling zinc toxicity for terrestrial invertebrates
Authors: Lock Koen , Janssen Colin R 
Published: March 2010

Abstract
Acute and chronic ecotoxicity tests with zinc were performed with the earthworm Eisenia fetida, the potworm Enchytraeus albidus, and the springtail Folsomia candida. To assess the influence of the soil type on zinc toxicity for these soil invertebrates, these tests were carried out in a standard artificial soil, a sandy and a loamy field soil. Based on the results of this experimental work and data taken from literature, models were developed relating the ecotoxicity of zinc to the most important parameters controlling bioavailability: pH and cation exchange capacity. Models were developed for E. fetida and F. candida using the regression technique partial least squares projection to latent structures (PLS). Acute as well as chronic toxicity data of both organisms could be normalized on the basis of the pH and the cation exchange capacity of the test soils. For other terrestrial invertebrates, not enough data were available to develop reliable models.
Natural exposure of coastal river otters to mercury: Relation to age, diet, and survival
Authors: Ben-David Merav , Duffy Lawrence K , Blundell Gail M , Bowyer R. Terry 
Published: March 2010

Abstract
We evaluated effects of location (i.e., Jackpot Bay, a naturally contaminated site, and Herring Bay, reference site), diet as determined by stable isotopes, and age on mercury concentrations in individual river otters (Lontra canadensis) from Prince William Sound, Alaska, USA. We also investigated the effects of mercury accumulation on survival of river otters from these two locations. Our results indicated that mercury concentrations in fishes from Jackpot Bay were significantly higher than those in fishes from Herring Bay and those in pelagic fishes. In addition, a predominant intertidal fish diet in both areas influenced the accumulation of mercury concentrations in otters. Concentrations of mercury in fur of river otters from Jackpot Bay were significantly higher than those of animals from Herring Bay. Nonetheless, we did not detect significant differences in survival between otters inhabiting the two areas, suggesting that this natural contamination was not high enough to impair survival. Our ability to investigate the effects of various factors such as location, diet composition, and age on mercury accumulation and subsequent survival of individuals offers an example for a link between individual-based captive studies and population-level field investigations.
Linking ecological impact to metal concentrations and speciation: A microcosm experiment using a salt marsh meiofaunal community
Authors: Millward Rod N , Carman Kevin R , Fleeger John W , Gambrell Robert P , Powell Rodney T , Rouse Mary-Anne M 
Published: March 2010

Abstract
Microcosm experiments addressed the impact of a mixture of Cu, Cr, Cd, Pb, and Hg at three concentrations after 36 h, 12 d, and 30 d on a meiofauna-dominated salt marsh community. In addition to analyzing effects on meiofaunal abundances, the study quantified the sediment metal concentrations of all five metals and pore-water concentrations, speciation, and ligand complexation of Cu. Abundances of deposit feeders such as the polychaete Streblospio benedicti, gastropods, and bivalves were impacted at lower metal concentrations than the mainly algal-feeding copepods, ostracods, and nematodes. We suggest that this might be due to bulk ingestion of metal-contaminated sediments resulting in relatively higher metal exposure in the deposit feeders than in the other, nondeposit feeding taxa. Copepod and ostracod abundances decreased only in the highest metal treatment, where levels of inorganic Cu ([Cu′]) in pore waters were similar to levels associated with both acute and subacute toxicity in published in vivo toxicity studies of marine copepods. The higher metal treatments yielded disproportionately higher pore-water [Cu] compared with sediment [Cu], suggesting saturation of sediment-associated ligands with increased additions of Cu. Similarly, the higher metal treatments appeared to reach saturation of the organic Cu ligands, with the excess pore-water [Cu] present in the more toxic, inorganic species of Cu. Acid-volatile sulfide (AVS) concentrations at sediment horizons inhabited by meiofauna were low and AVS was not considered a significant metal ligand at these depths. Since meiofauna are predominantly associated with oxic surface sediments, it is doubtful that AVS is a major factor controlling availability of free metal for exposure to these taxa.
Plant-facilitated mobilization and translocation of weathered 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene(p,p′-DDE) from an agricultural soil
Authors: White Jason C 
Published: March 2010

Abstract
Field experiments were conducted to determine the uptake and translocation of highly weathered 2,2-bis(p-chlorophenyl)1,1-dichloroethylene (p,p′-DDE) from an agricultural soil. In soil containing known amounts of p,p′-DDE, experimental plots containing zucchini, pumpkin, or spinach were constructed. At destructive harvest, three soil fractions were collected that differed in the degree of influence exerted by the plant roots. The bulk soil was vegetation-free, the near-root zone was within the area encompassed by the roots, and the rhizosphere remained physically attached to the roots at harvest. For each crop, statistically significant decreases were found in the concentration of p,p′-DDE in either the near-root zone or the rhizosphere relative to the bulk soil, suggesting plant-facilitated mobilization and/or degradation of the residue. Plant tissues were analyzed to determine the extent of contaminant removal from the soil and the magnitude of translocation through the shoot system. The concentration of p,p′-DDE in the roots of both zucchini and pumpkin was more than an order of magnitude larger than the bulk soil concentration, followed by significant translocation through the plant tissues to the fruit. The data indicate that certain plants may effectively accumulate residues of persistent organic pollutants in their tissues, suggesting phytoremediation as a possible treatment strategy.
Characterization of salinity-enhanced toxicity of aldicarb to Japanese medaka: Sexual and developmental differences
Authors: El-Alfy Abir T , Grisle Sonja , Schlenk Dan 
Published: March 2010

AbstractThe effects of salinity, gender, and development on the acute toxicity of aldicarb were examined in the euryhaline fish, Japanese medaka (Oryzias latipes). The 96-h median lethal concentrations (LC50s) at 1.5 parts per thousand (‰) salinity were not significantly different between adults and juveniles but larvae were significantly more sensitive to aldicarb. A two-week exposure to increased salinity significantly enhanced the toxicity of 0.5 ppm aldicarb to both sexually mature male and female medaka. After 48 h of aldicarb exposure, mortality significantly increased (p &lt; 0.05) in males from 13 ± 5.7% at 1.5‰ salinity to 56 ± 5.7% at 20‰; in females mortality significantly increased (p &lt; 0.01) from 17 ± 5.7% to 76 ± 5.6%. A time-course study was conducted in which muscle acetylcholinesterase (AChE) inhibition was monitored after exposure to aldicarb. In general, AChE in females was inhibited to a greater degree at 12.0 and 20.0‰ salinity regimens than AChE in males. Muscle AChE in females residing at 20.0‰ was inhibited 93 ± 3.3% by 8 h of exposure to 0.95 ppm aldicarb, whereas in males the maximum inhibition was 80 ± 7.4% after 8 h of exposure to 0.86 ppm aldicarb at 20‰ salinity. These results indicate that environmental factors, such as salinity, in addition to gender and development, have significant impacts on the acute toxicity of aldicarb to Japanese medaka.
Trophic transfer and passive uptake of a polychlorinated biphenyl in experimental marine microbial communities
Authors: Wallberg Petra , Jonsson Per R , Andersson Agneta 
Published: March 2010

AbstractTo study the uptake mechanisms of 2,2′,4,4′,6,6′-hexachlorobiphenyl (HxCB 153) in microplankton with different feeding strategies, two laboratory communities were used. Trophic transfer of HxCB 153 was tested in a heterotrophic microbial food web consisting of bacteria, flagellates, and ciliates. Passive uptake was tested in a community consisting of algae and bacteria. The experiments were conducted over 6 d, and samples were retrieved daily. In the heterotrophic food web, a significant increase of the HxCB 153 concentration was observed in the top predator level (ciliates, p &lt; 0.05), where the concentration doubled during the 3 d of the experiment. A concomitant decrease was observed in the ciliate prey (flagellates), indicating that HxCB 153 was redistributed due to trophic transfer. On average, 33% of the HxCB 153 was sorbed to ciliates over the course of the experiment. In the experiment with algae and bacteria, the HxCB 153 concentrations were relatively stable over time. The largest fraction partitioned into bacteria (57%), whereas only 4% of the HxCB 153 sorbed to the algae. The uptake was 8-fold higher in ciliates than in algae, although the algal biomass was 10-fold higher. The results imply that trophic transfer may be a significant transport route of more hydrophobic organic contaminants (HOCs) in plankton communities. In transfer models, this pathway may be taken into consideration so that the transport rate of HOCs to higher trophic levels is not underestimated.