bluuebunny/crossref_metadata_2025 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

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

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

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

Aquatic 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

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

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

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 (>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

Using 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

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

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

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

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

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

The 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 < 0.05) in males from 13 ± 5.7% at 1.5‰ salinity to 56 ± 5.7% at 20‰; in females mortality significantly increased (p < 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

To 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 < 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.
Effect of petrochemical sludge concentrations on changes in mutagenic activity during soil bioremediation process
Authors: Morelli Irma Susana , Vecchioli Graciela Isabel , Del Panno María Teresa , Painceira María Teresa
Published: March 2010

The present study was performed to assess the effect of the petrochemical sludge application rate on the mutagenic activity (Ames test) of soil and the persistence of mutagenic activity during laboratory soil bioremediation process. Sludge-soil systems were prepared at four different sludge application rates (1.25, 2.5, 5, and 10% w/w). Unamended soil was used as a control. Immediately following sludge application, in the absence or presence of S9, a linear correlation between sludge application rates and mutagenicity was found but differed significantly (p < 0.05) from the control system only at higher application rates (5 and 10% w/w). The direct mutagenicity of all systems decreases during the bioremediation process, and after a year of treatment only the 10% system induced a mutagenic response that was significantly different from the control system. On the other hand, an initial increase of the indirect mutagenicity was observed at all application rates. The time required for observing this increase was inversely proportional to the initial sludge concentration. After a year of treatment, the indirect mutagenicity of all sludge-amended soils was not significantly different but was significantly different from the unamended soils. The persistence of the direct mutagenic activity of the sludge-amended soils was related to the sludge concentration, whereas the indirect mutagenic persistence was related to the relationship between easily degradable hydrocarbons and polynuclear aromatic hydrocarbons concentration and independent from the initial application rate.
The effect of 2,5,2′,5′-tetrachlorobiphenyl on growth and death of the cyanobacterium Anabaena flos-aquae
Authors: Lee Dae-Young , Rhee G-Yull
Published: March 2010

The effect of 2,5,2′,5′-tetrachlorobiphenyl (TcBP) on cell death was investigated in the cyanobacterium Anabaena flosaquae (Lyngb.) Bréb grown in a P-limited, semicontinuous culture under N2-fixing conditions during a 17-d period. The TcBP was supplied daily to yield final concentrations of 1, 10, and 100 ppb (or ng/ml). At 1 and 10 ppb, the population size of live cells (sum of live vegetative cells and live heterocysts) was not different from that of the TcBP-free controls (p > 0.1, t test) and remained constant both in its absolute value (9.6 × 105 cells/ml) and as a percentage of the total population (98.6%). However, at 100 ppb, the population size of live cells declined significantly after the 11th day (8.2 × 105 cells/ml, or 96.6% of total population; p < 0.01, t test). The decrease in viable cells was mostly found in vegetative cells. Bioconcentration factor in the cell ([pg TcBP/g dry wt cells]/[pg TcBP/ml]) was 1.23 × 105.
Assessment of the estrogenicity and toxicity of a domestic wastewater effluent flowing through a constructed wetland system using biomarkers in male fathead minnows (Pimephales promelasrafinesque, 1820)
Authors: Hemming Jon M , Waller William T , Chow Marjorie C , Denslow Nancy D , Venables Barney
Published: March 2010

The toxicity and estrogenicity of a final treated municipal effluent was examined while flowing through a constructed wetland in north-central Texas, USA. Fish data were collected, and a baseline wetland characterization was performed to assess wetland treatment potential for these effluent properties. Vitellogenin (VTG), gonadosomatic index (GSI), hepatosomatic index (HSI), and secondary sexual characteristics were biomarkers used in fish models to assess aqueous estrogenicity. Biological indicators used to assess overall fish health included hematocrit and condition factor. Estrogenic nature of final sewage treatment works effluent was screened, concurrent with a three-week fish exposure, via gas chromatography/mass spectrometry for target estrogenic compounds, including 17β-estradiol, ethynylestradiol, bisphenol A, nonylphenolic compounds, phthalates, and DDT. The VTG in Pimephales promelas was measured after exposure at four sites in a treatment wetland and was significantly elevated (p < 0.0001) in fish exposed at the inflow site. The GSIs were significantly less (α = 0.001) at the inflow site. At wetland sites closest to the inflow, secondary sexual characteristics, tubercle numbers, and fatpad thickness were less (α = 0.0001) than in laboratory controls. The HSIs and density of male breeding stripes were not significantly different from those of laboratory controls. However, elevated HSIs were found at the inflow site. Hematocrit and condition factors were both less (α = 0.001) in effluent-exposed fish at wetland sites closer to the inflow than in control fish or fish further downstream.
Toxicokinetics of waterborne bisphenol a in landlocked salmon (Salmo salar m. Sebago) eggs at various temperatures
Authors: Honkanen Jani O , Heinonen Jari , Kukkonen Jussi V.K.
Published: March 2010

Eye-pigmented eggs of landlocked salmon were exposed to waterbone [14C]-labeled bisphenol A at four temperatures (2, 6, 8, and 12°C). Both in accumulation and depuration experiments, the eggs were exposed to a bisphenol A concentration of 1 μg/L for 196 h. In the depuration experiment, the exposed eggs were placed into clean water for 96 h. At each sampling time, the eggs were dissected into three parts (eggshell, embryo, and yolk sac), and all of these parts were weighed and analyzed separately in a liquid scintillation counter. The results show that waterborne bisphenol A accumulates in developing salmon eggs. Accumulation of bisphenol A showed a clear trend both in whole eggs and in dissected parts: the higher the temperature, the higher the uptake rate constant and the concentration of bisphenol A. Steady state was reached only in the embryos at the lowest temperature; in other cases, accumulation was linear. Depuration was significant only in the embryos at 2 and 6°C. As the accumulation and the depuration results show, the elimination of bisphenol A was evidently more significant at lower temperatures.
Juvenile amphibians do not avoid potentially lethal levels of urea on soil substrate
Authors: Hatch Audrey C , Belden Lisa K , Scheessele Erin , Blaustein Andrew R
Published: March 2010

We examined the effects of a forest fertilizer (urea) on newly metamorphosed terrestrial amphibians (Western toads, Bufo boreas; Cascades frogs, Rana cascadae; long-toed salamanders, Ambystoma macrodactylum; and roughskin newts, Taricha granulosa). We examined avoidance behavior of Western toads and Cascades frogs on both paper towel and soil substrates dosed with urea (control and 100 kg N/ha and an additional treatment of 50 kg N/ha for Western toads on soil substrate) and avoidance behavior of long-toed salamanders on soil substrate dosed with urea. We further examined the survival and feeding behavior of all four species exposed to urea on soil substrate (100 kg N/ha) for 5 d. Juvenile Western toads and Cascades frogs avoided paper towels dosed with urea but did not avoid urea-dosed soil substrate. However, Western toads and Cascades frogs both suffered significant mortality when exposed to urea on a soil substrate for 5 d. Furthermore, after adjusting for weight, we found that urea-exposed juvenile Western toads and Cascades frogs consumed significantly fewer prey items (crickets) compared with nonexposed control animals. Long-toed salamanders did not discriminate against soil substrate dosed with urea, and neither long-toed salamanders nor roughskin newts died or reduced prey consumption as a result of urea exposure. Juvenile amphibians may not be able to detect and avoid harmful levels of urea fertilizer on a natural substrate. Furthermore, anthropogenic stressors such as urea fertilizer can significantly reduce the survival and prey consumption of juvenile amphibians. These effects are important to consider in light of possible threats to the conservation status of many amphibian species.
Metal–colloid partitioning in artificial interstitial waters of marine sediments: Influences of salinity, pH, and colloidal organic carbon concentration
Authors: Cantwell Mark G. , Burgess Robert M
Published: March 2010

For decades, heavy metals have been deposited into marine sediments as a result of anthropogenic activities. Depending on their bioavailability, these metals may represent a risk to benthic organisms. Dissolved interstitial water metal concentrations have been shown to be better predictors of bioavailability than sediment metal concentrations. In order to improve our understanding of metals bioavailability in sediments, it is essential to fully comprehend metal speciation. Colloidal organic carbon is ubiquitous in marine interstitial water and readily forms complexes with numerous dissolved metals, greatly reducing their bioavailability. Methods were applied to isolate dissolved and colloidal cadmium, copper, nickel, lead, and zinc from interstitial waters using centrifugation and stirred cell ultrafiltration. Influences of salinity, pH, and colloidal carbon concentration on partitioning behavior were investigated. In the pH study, colloidal-dissolved partitioning of each metal (Kp) was observed to increase as pH rose. Conversely, in the salinity experiment, metal Kps declined as salinity increased. For the metal–organic colloid study, linear isotherms were calculated for each of the metals, resulting in log Kcocs ranging from 5.90 for zinc to 7.50 for copper. Kp values calculated from metal-spiked field sediments were in good agreement with those measured in the salinity study. These results provide insight into the behavior of metals associated with colloidal organic carbon in marine sediments under the conditions occurring in estuarine systems.
Hydrocarbon humps in the marine environment: Synthesis, toxicity, and aqueous solubility of monoaromatic compounds
Authors: Smith Emma , Wraige Emma , Donkin Peter , Rowland Steven
Published: March 2010

A recent study has shown that some monoaromatic hydrocarbon constituents of the so-called unresolved complex mixtures (UCMs) or gas chromatographic humps, which are widespread in the marine environment, are toxic to the mussel Mytilus edulis. Here we describe the synthesis and toxicological assessment of 6-cyclohexyltetralin, 7-cyclohexyl-1-methyltetralin, and 7-cyclohexyl-1-n-propyltetralin, which contain structural features consistent with some monoaromatic UCM hydrocarbons. The compounds were all toxic to M. edulis when measured in the assay used previously to determine the toxicity of a monoaromatic UCM. The aqueous solubilities of the hydrocarbons in fresh and seawater at different temperatures were determined and found to range from about 10 to 110 μg/L (10–60 μg/L in seawater at 15°C). Further studies of the aromatic UCM composition of a wide range of oils and oil residues are required to determine whether such alkylated compounds as 7-cyclohexyl-1-methyltetralin and 7-cyclohexyl-1-n-propyltetralin or their analogues are widespread in oils. If these aromatic compounds prove to be important in UCMs, toxicity experiments should be conducted with other biological end points and monitoring studies of pollutant hydrocarbons should probably include measurement of aromatic UCM hydrocarbons.
A novel toxicity fingerprinting method for pollutant identification with lux-marked biosensors
Authors: Turner Nigel L , Horsburgh Alison , Paton Graeme I , Killham Ken , Meharg Andrew , Primrose Sandy , Strachan Norval J C
Published: March 2010

At present, monitoring and identification of environmental pollutants in freshwater is performed predominantly by laboratory-based chemical analysis. Such an approach is often time-consuming and expensive and requires prior knowledge of the pollutants present for most practical purposes, because chemical identification techniques are generally specific to individual pollutants or pollutant classes [3]. In addition, total pollutant load does not always accurately reflect environmental toxicity because pollutant bioavailability is dependent upon water chemistry. For these reasons, a movement is increasing toward the use of biological techniques for the monitoring of environmental pollution by industry and regulators alike [2].
Impact of vinclozolin on reproductive behavior and endocrinology in Japanese quail (Coturnix coturnix japonica)
Authors: McGary Sabrina , Henry Paula F P , Ottinger Mary Ann
Published: March 2010

The impact of endocrine-disrupting chemicals (EDCs) has been demonstrated in mammalian models, but less research is available for avian species. The effects of vinclozolin (VIN), an antiandrogenic fungicide, on sexual differentiation and maturation were investigated in Japanese quail (Coturnix coturnix japonica). On day 4 of incubation, embryos were exposed to no treatment, oil, or 25, 50, or 100 ppm of VIN. Endpoints measured included adult male reproductive behavior, hypothalamic gonadotropin-releasing hormone I (GnRH-I) content in hatchlings and adults, plasma steroid levels in hatchlings and adults, proctodeal gland growth during maturation, and relative testicular weight at seven weeks of age. Results showed that exposure to VIN significantly (p < 0.05) altered GnRH-I in male hatchlings, whereas GnRH-I levels in females remained unaffected. Although steroid levels were unaltered by any VIN treatment, the display of male reproductive behavior seemed delayed, with the number of mounts and the number of cloacal contacts being significantly (p < 0.05) lower in the VIN-treated males. This could have an extreme negative impact on wild avian species that are routinely exposed to similar EDCs.
A comparison of biomarker responses in the earthworm Aporrectodea caliginosa to the organophosphorus insecticides diazinon and chlorpyrifos
Authors: Booth Lynn H , O'Halloran Kathryn
Published: March 2010

Three biomarkers in Aporrectodea caliginosa Savigny were evaluated for their ability to detect exposure to organophosphorus insecticides, and these physiological responses were related to effects on growth and life-table parameters. Adult and juvenile earthworms were exposed to a laboratory-simulated field rate (low concentration) and a higher sublethal concentration of diazinon and chlorpyrifos. After a four-week exposure, juveniles were evaluated for cholinesterase activity, glutathione S-transferase activity, and growth, and adults were evaluated for the lysosomal neutral red retention assay (NRRA) and growth. Cholinesterase activity and the NRRA were more sensitive than growth in each age group for detecting exposure to the pesticides. Life-table parameters were evaluated in earthworms exposed as juveniles and as adults. Maturation was less sensitive to pesticides than was cocoon production. Growth and cocoon production in earthworms exposed as juveniles appeared to be more sensitive to organophosphorus insecticides than earthworms exposed as adults. Life-table responses in juveniles may, therefore, be more predictive of long-term impacts of organophosphorus insecticide applications on populations than responses in adults. Biomarker responses occurred at similar or lower concentrations than those causing an adverse effect on cocoon production and cocoon viability, indicating their usefulness in risk assessment for predicting ecologically relevant assessment end points.
Environmental quality standards: Endpoints or triggers for a tiered ecological effect assessment approach?
Authors: Sijm Dick , de Bruijn Jack , Crommentuijn Trudie , van Leeuwen Kees
Published: March 2010

The recently derived Dutch Environmental Quality Standards (EQS) for water, soil, and sediment for approximately 170 substances have been evaluated. Three methods have been used to derive the Dutch EQS. Independent of how the EQS were derived, they are given equal weight in Dutch environmental policy. Scientifically, the three methods may deserve different weights. For example, for soil and sediment, the least reliable method had to be applied to derive most of the EQS. Ecological effects in these compartments may be either overestimated or underestimated. A multitiered approach is proposed, which is relevant for all parties involved, including other countries, and which may help improve ecological effect assessment.
Structure–specificity relationships for haloalkane dehalogenases
Authors: Damborský Jiří , Rorije Emiel , Jesenská Andrea , Nagata Yuji , Klopman Gilles , Peijnenburg Willie J G M
Published: March 2010

A structural analysis of the substrate specificity of hydrolytic dehalogenases originating from three different bacterial isolates has been performed using the multiple computer-automated structure evaluation methodology. This methodology identifies structural fragments in substrate molecules that either activate or deactivate biological processes. The analysis presented in this contribution is based on newly measured dehalogenation data combined with data from the literature (91 substrates). The enzymes under study represent different specificity classes of haloalkane dehalogenases (haloalkane dehalogenase from Xanthobacter autotrophicus GJ10, Rhodococcus erythropolis Y2, and Sphingomonas paucimobilis UT26). Three sets of structural rules have been identified to explain their substrate specificity and to predict activity for untested substrates. Predictions of activity and inactivity based on the structural rules from this analysis were provided for those compounds that were not yet tested experimentally. Predictions were also made for the compounds with available experimental data not used for the model construction (i.e., the external validation set). Correct predictions were obtained for 28 of 30 compounds in the validation set. Incorrect predictions were noted for two substrates outside the chemical domain of the set of compounds for which the structural rules were generated. A mechanistic interpretation of the structural rules generated provided a fundamental understanding of the structure–specificity relationships for the family of haloalkane dehalogenases.
Factors affecting the occurrence and enantiomeric degradation of hexachlorocyclohexane isomers in northern and temperate aquatic systems
Authors: Law Sheryl A , Diamond Miriam L , Helm Paul A , Jantunen Liisa M , Alaee Mehran
Published: March 2010

Concentrations of α- and γ-hexachlorocyclohexane (HCH), α/γ-HCH ratios, and enantiomer ratios (ER) of α-HCH were measured in lakes in the arctic, subarctic, Great Lakes, Canada, and temperate regions, and temperate and arctic wetlands and streams. The highest concentrations of α-HCH were found in cold, large, and oligotrophic lakes such as those in the arctic, subarctic, and the upper Great Lakes, which is attributed to greater inputs from atmospheric deposition and slower loss rates relative to warmer, temperate lakes. High α/γ-HCH ratios in northern systems indicate aged HCH that has undergone long-range transport to high latitude areas, whereas low ratios in the lower Great Lakes and small temperate systems indicate recent γ-HCH usage and residual α-HCH concentrations. Enantioselective degradation (ERs ranged from 0.31 to 0.7) was greatest in small, high arctic lakes and streams and in large lakes in the subarctic in which α-HCH concentrations and contact time between chemical and sediments are highest and nutrient concentrations are lowest. Low ERs were found in wetlands and streams in which contact between chemical and sediments was greatest. Conversely, minimal enantioselective degradation occurred in temperate small lakes and wetlands (ERs ranging from 0.77 to 1.06), despite the warmer temperatures, greater microbial populations, and nutrient availability. The results suggest that enantioselective degradation is optimized by maximal contact between chemical and sediment substrates in nutrientpoor waters in which, it is hypothesized, oligotrophic bacteria may act as biofilms.
Aryl hydrocarbon receptor-mediated and estrogenic activities of oxygenated polycyclic aromatic hydrocarbons and azaarenes originally identified in extracts of river sediments
Authors: Machala Miroslav , Ciganek Miroslav , Bláha Luděk , Minksová Kateřina , Vondráčk Jan
Published: March 2010

Reproductive dysfunction in wildlife populations can be a result of environmental contaminants binding to aryl hydrocarbon receptor (AhR) or estrogenic receptors. Signaling by both types of receptors can be affected by polycyclic aromatic hydrocarbons (PAHs), which are potential endocrine disruptors. However, our knowledge regarding the effects of oxygenated (oxy)-PAHs and azaarenes on AhR-mediated and estrogenic activities is incomplete. In the present study, we have identified 9-fluorenone, anthrone, anthraquinone, benzanthrone, benz[α]anthracene-7,12-dione, benz[c]acridine, and dibenz[a, h]acridine as prevalent oxy-PAHs and azaarenes found in river sediments. Their concentrations in sediment samples ranged from 2.1 to 165.2 ng g−1 for oxy-PAHs and up to 27.3 ng g−1 for azaarenes. Their relative AhR-inducing and estrogenic potencies were quantified in vitro using two cell lines that were stably transfected with a luciferase reporter gene system and expressed as induction equivalency factors (IEFs). The only oxy-PAHs with detectable levels of in vitro AhR-mediated activity were benzanthrone and benz[a]anthracene-7,12-dione. However, their IEFs were approximately three to four orders of magnitude lower than those of benzo[a]pyrene. On the other hand, azaarenes showed a strong AhR-mediated activity, with dibenzo[a, h]acridine being a far more potent inducer of activity than benzo[a]pyrene. Benzanthrone, benz[a]anthracene-7,12-dione, anthraquinone, and benz[a]acridine were weak inducers of in vitro estrogenic activity, with IEFs similar to that of benzo[a]pyrene. Based on concentrations and relative potencies, our results suggest that dibenzo[a, h]acridine can significantly contribute to the overall AhR-mediated activity in river sediments, whereas the remaining compounds do not. No studied compound was found to contribute significantly to estrogen receptor–mediated activity in vitro.
Chlorodifluoroacetic acid fate and toxicity to the macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum in aquatic microcosms
Authors: Hanson Mark L , Sibley Paul K , Mabury Scott A , Muir Derek C , Solomon Keith R
Published: March 2010

Chlorodifluoroacetic acid (CDFA) is a novel haloacetic acid (HAA) and has been recently documented in aquatic systems. It is a suspected degradation product of the refrigerants 1,1,2-trichloro-1,1-difluoroethane (CFC-113) and 1-chloro-1,1-difluoroethane (HCFC-142b). Haloacetic acids can be phytotoxic, putatively acting through inhibition of the citric acid cycle. Replicate (n = 3) 12,000-L model aquatic ecosystems (microcosms) were dosed once at 0.5, 1, 5, and 20 mg/L of neutralized CDFA. Three microcosms served as controls. Each microcosm was stocked with eight individual apical shoots of both Myriophyllum spicatum and Myriophyllum sibiricum and sampled at regular intervals over a 42-d exposure period. The plants were assessed for the somatic endpoints of plant length, root growth, node number, and wet and dry mass and the biochemical endpoints of chlorophyll-a/b and carotenoid content as well as citric acid levels. The duckweed Lemna gibba was also introduced into these systems and monitored over a period of 14 d for wet/dry mass, plant/frond number, chlorophyll content, and growth rate. Concentrations of CDFA remained constant in the water column over the course of the fate investigation (241 d), indicating that this compound undergoes little, if any, degradation in aquatic systems. Results showed few statistically significant differences from controls for all three plant species with exposure to CDFA but no biologically relevant impacts. Overall, CDFA does not appear to pose any risk to these aquatic macrophytes at current environmental concentrations.