bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioaccumulation of polychlorinated biphenyls from sediments to aquatic insects and tree swallow eggs and nestlings in Saginaw Bay, Michigan, USA
Authors: Froese Kenneth L , Verbrugge David A , Ankley Gerald T , Niemi Gerald J , Larsen Christen P , Giesy John P 
Published: March 2010

Abstract
Sediments in the Saginaw Bay region of the Great Lakes contain concentrations of polychlorinated biphenyls (PCBs) that may adversely affect biotic species in various trophic levels. In this study we collected and analyzed sediments, benthic invertebrates, tree swallow eggs, and nestlings to evaluate linkages between PCBs in sediments and at various trophic levels in the Saginaw River, Michigan, USA. Our results indicate that patterns of relative concentrations of PCB congeners change with trophic level, specifically from sediment to invertebrates and from tree swallow eggs to nestlings. However, if biota–sediment accumulation factor (BSAF) values are based on only the non- and mono-ortho-substituted PCB congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEq), calculated BSAF values are close to those predicted by fugacity theory. The use of site-specific BSAF values and reference doses for toxic effects in wildlife can be used to derive sediment quality criteria (SQC) that are protective of wildlife at the top of the sediment-based food chain. The threshold concentration of TEq in sediments that would protect sensitive avian species at the same trophic level as tree swallows was calculated to be 1.5 × 10−1 TEq/g total organic carbon. Based on this value and the BSAF determined for tree swallow nestlings, the hazard quotient for sediments in this area was determined to be 0.7. This indicates that current concentrations of TEq due to PCB congeners in the sediments should be below the threshold for adverse effects on tree swallows. The uncertainty in the concentrations of PCB congeners in the sediments was approximately a factor of 2, which determined the degree of resolution that could be obtained from the observations made in this study.
Toxicology of white phosphorus (P4) to ducks and risk for their predators: Effects of particle size
Authors: Roebuck Bill D , Nam Sae-Im , MacMillan Denise L , Baumgartner Karen J , Walsh Marianne E 
Published: March 2010

Abstract
Particles of white phosphorus (P4) in pond sediments at Eagle River Flats, Alaska, USA, a military artillery range are acutely toxic to dabbling ducks and swans. We determined if toxicity of P4 to ducks varied by its form (i.e., dissolved or particulate) or particulate size. Residual P4 in the digestive tracts of ducks was measured to assess risks posed to predators and scavengers of ducks. Farm-reared mallards were treated with 12 mg P4/kg body weight, either dissolved in oil, or as numerous small, or one to two large particles. At the first major convulsion, ducks were euthanized and the quantity and location of P4 in the digestive tract were determined. These data were compared to data from dead ducks collected from the artillery range. Dissolved, small, or large particles of P4 produced similar acute toxicity. Residual P4 in digestive tracts was greatest in ducks treated with small particles and was as great as 3.5 mg P4. Similar quantities of residual P4 were found in dead ducks collected at Eagle River Flats. For dabbling ducks, P4 particle size is not as important as the dose ingested. For predators, the P4 contents of the entire digestive tract is important for assessment of the risk of poisoning.
Sources of silver in the environment
Authors: Purcell Thomas W , Peters Jennifer J 
Published: March 2010

Abstract
Silver is a naturally occurring metal that is extensively utilized in the photographic and imaging industry, as well as in electronics and electrical applications and other lesser uses. It is known to be discharged to the environment from its industrial applications, and this leads to the possibility for exposure to aquatic and terrestrial organisms. Because of great differences in toxicity between silver compounds, the form in which silver enters the environment is important. While the ionic form of silver has been shown to be toxic to a variety of aquatic organisms, forms of silver other than ionic, or free, silver are significantly less toxic. Ionic silver is known to convert to the more innocuous forms as it reacts rapidly with natural chemical ligands in sewer systems, sewage treatment facilities, and the environment. This paper reviews information on the industries that use silver, the quantities they employ, and the forms and amounts of silver that may be discharged from each into the environment.
Toward a better understanding of the bioavailability, physiology, and toxicity of silver in fish: Implications for water quality criteria
Authors: Hogstrand Christer , Wood Chris M 
Published: March 2010

AbstractIn its ionic form, silver (Ag+) is highly toxic to fish (96-h 50% lethal concentration [LC50]: low μg/L range). However, concentrations of Ag+ in aquatic environments are extremely low and other more common forms of silver show only low to moderate toxicities (e.g., 96-h LC50: silver thiosulfate &gt;100,000 μg Ag/L; silver chlorides &gt;100 μg Ag/L). In bioassays with freshwater fish, acute toxicity appears to be derived exclusively from the Ag+ ion concentration of the water. Some other forms of silver are bioavailable but do not show obvious contribution to acute toxicity. Complexation of Ag+ by chloride, dissolved organic carbon, and sulfide are important in reducing silver toxicity. The protective action of hardness (i.e. calcium) is modest. When added as the readily dissociating silver nitrate salt, the toxicity of silver is considerably lower in seawater (96-h LC50 range: 330–2,700 μg Ag/L) than in freshwater (96-h LC50 range: 5–70 μg Ag/L). Acute silver toxicity to fish is caused by failure of the organism to maintain constant Na+ and Cl− concentrations in the blood plasma. In freshwater fish, Ag+ exerts its toxic effects on the Na+ and Cl− transport across the gills, whereas the intestine has been indicated as the site of toxicity in seawater fish. Although there are still many gaps in our understanding of silver effects on fish, it can be concluded that present regulatory standards for silver can be much improved by taking into account the important geochemical modifiers of silver toxicity.
Physiological analysis of the stress response associated with acute silver nitrate exposure in freshwater rainbow trout (Oncorhynchus mykiss)
Authors: Webb Nathan A , Wood Chris M 
Published: March 2010

Abstract
Rainbow trout were exposed to AgNO3 (9.2 μg/L total Ag, of which 35% was as the free ion, Ag+) for a 6-d period in dechlorinated Hamilton tapwater. Our findings suggest that the primary toxic mechanism of Ag is an interruption of ionoregulation at the gills, stopping active Na+ and Cl− uptake without increasing passive efflux, thereby causing net ion loss. There is no recovery of influxes over 6 d, whereas effluxes are gradually reduced below control levels, and ion balance remains negative. The resulting fall in plasma [Na+] and [Cl−] leads to a decrease in plasma volume and hemoconcentration, but the red blood cells do not swell. A substantial metabolic acidosis with partial respiratory compensation occurs in the blood, due to a net uptake of acidic equivalents from the environmental water. This uptake greatly exceeds the measured acid load in the extracellular fluid, suggesting that acidosis also occurs in the intracellular compartment, which in turn explains the continual loss of K+ to the water in the absence of any change in plasma [K+]. Plasma ammonia, glucose, and cortisol rise. As there is no reduction but rather a progressive rise in ammonia excretion, the increase in plasma ammonia is due to elevated metabolic production rather than inhibited excretion. The cause is probably the stress-induced mobilization of cortisol. This increased plasma ammonia, in conjunction with hyperventilation, helps to counteract metabolic acidosis. However, because the fish is unable to counteract the loss of plasma ions, death eventually results from a severe ionoregulatory disturbance.
Acute silver toxicity to seawater-acclimated rainbow trout: Influence of salinity on toxicity and silver speciation
Authors: Ferguson Elizabeth A , Hogstrand Christer 
Published: March 2010

Abstract
While there is considerable information on freshwater toxicity of Ag to fish, little is known about the toxicity of Ag in marine systems. In the present study, standard 96-h acute toxicity tests were performed on seawater-acclimated rainbow trout in water at 25‰salinity. Toxicity tests were repeated in various salinities (15, 20, 25, and 30‰) at the 50% lethal concentration (LC50) for Ag in 25‰ to investigate the influence of salinity on toxicity. Computer speciation modeling by MINEQL+ was performed in order to gain insight into the variation of Ag species over a range of salinities from freshwater to oceanic seawater at S2–-free conditions. At 25‰salinity the LC50 was determined to be 3.75 μM (401 μg/L) Ag. No mortality was observed at this Ag concentration in 15 or 20‰ salinities. Mortality increased to 50% in 25‰ seawater and again to 67% at 30‰. Based on the results of speciation modeling, an increase in a more toxic AgCln species is unlikely. The increased toxicity with salinity may instead be linked to an incomplete hypoosmoregulatory ability of the rainbow trout.
Toxicity of silver sulfide-spiked sediments to the freshwater amphipod (Hyalella azteca)
Authors: Hirsch Marianne P 
Published: March 2010

AbstractNatural freshwater sediments were spiked in the laboratory with silver sulfide (Ag2S), and semistatic toxicity tests were conducted with a series of sediment silver (Ag) concentrations ranging from 1.27 to 753.3 mg/kg of sediment. Water was added to glass beakers containing either the Ag2S-amended or the control sediment. Each of the Ag2S-amended and control sediments was tested in replicates of eight. Ten juvenile Hyalella azteca were added to each beaker at test start. The overlying water was renewed twice daily. The 10-d 50% lethal concentration value for Ag as Ag2S for H. azteca was determined to be &gt;753.3 mg/kg, the highest analyzed concentration tested. There were no statistically significant differences in survival rates of H. azteca exposed to any of the Ag2S-amended sediments when compared to the control. In addition, there were no concentration–response trends for mean survival or average dry weight data from this study, indicating that this form of silver was not bioavailable under these conditions.
Removal, partitioning, and fate of silver and other metals in wastewater treatment plants and effluent-receiving streams
Authors: Shafer Martin M , Overdier Joel T , Armstong David E 
Published: March 2010

Abstract
We investigated the removal of silver in five publicly owned treatment works (POTWs) and the fate of Ag in effluent receiving streams. Comparisons were made to several other metals. Silver was removed efficiently (&gt;94%) in all POTWs. The percentage of total Ag removed was independent of the influent Ag concentration, while the concentration of Ag in effluents was directly related to influent concentration. A good correlation (r2 = 0.77) between metal removal (%) and partition coefficient (Kd) indicated that differences among metals in removal efficiency were controlled mainly by metal partitioning (sorption) to particles removed by settling and/or filtration. A large fraction (19–53%) of Ag in the filterable (&lt; 1.0-μm) fraction of POTW effluents was associated with submicron particles or colloids (&gt;0.05 μm), and the percentage filterable Ag was directly related to DOC concentration (r2 = 0.96). Effluent Ag concentrations (0.06–2.6 μg/L) were several orders of magnitude higher that typical “background” stream levels (1–2 ng/L), but Ag discharged to streams was rapidly dissipated by dilution and incorporation into stream sediments.
Determination of silver ions at submicrogram-per-liter levels using anodic square-wave stripping voltammetry
Authors: Schildkraut Deniz E , Dao Phat Tan , Twist John P , Davis Ann T , Robillard Ken A 
Published: March 2010

Abstract
Square-wave stripping voltammetry at a carbon paste electrode was used to develop a method to measure silver ions at concentrations as low as 0.2 μg/L in surface waters. Sample matrix was found to be an important factor affecting the measurement results. Because of these matrix effects, the peak shape of the voltammograms varied, and multiple stripping peaks for silver were observed. Total charge provided a more reliable measure of deposited silver than did peak height. The precision of the method for the analysis of standard reference materials containing silver was estimated to be 7.2% relative SD at 1 SD using a 95% confidence interval of the individuals. A full factorial experiment was performed to determine how the following factors affected measurement variability: electrode, renewal of the carbon paste electrode surface, silver ion concentration, preparation of standards and samples, and day-to-day variability. Samples of lake and river water were collected and analyzed for silver ion. In all samples the measured concentration of silver ion was &lt;0.2 μg/L, whereas the concentration of total silver was typically &gt;0.5 μg/L. Spiking experiments showed that the constituents of the river water samples had a greater ability to bind (remove) silver ion than did the lake water.
Partitioning and mineralization of [14C]lindane in a laboratory sediment–water system
Authors: Kalsch Wolfgang , Knacker Thomas , Robertz Markus , Studinger Gabriele , Franke Christian 
Published: March 2010

Abstract
To develop a guideline for a simulation test for aerobic degradability in surface water, the fate of [14C]lindane (γ-hexachlorocyclohexane) was studied in laboratory systems using natural river water and sediments. No sterilized controls were set up. Thus, measured data reflect the sum of biotic and abiotic processes. Tests were carried out under various experimental conditions to investigate which of these would affect the feasibility of the test, the fate of lindane, the physicochemical state, and the biological activity within the sediment–water systems. Lindane (37.7 nmol) was applied either to the water (3 L) or the sediment (0.33 L). Sediments remained nonreducing, and there was no serious decline of nutrients nor enzymatic activities. In one experiment up to 14.1% of the applied lindane was mineralized to 14CO2 within 50 d and in a second one up to 35.3%. At day 91 of the latter experiment up to 46.8% were found to have been mineralized. Among the experimental factors tested, the method of lindane application and temperature predominantly affected mineralization. The type of aeration and the semicontinuous addition of organic nutrients were of minor importance. Sediments and water collected at the same site but at different times showed variation in carbon content as well as in esterase and dehydrogenase activities. Nevertheless, these parameters could not be correlated with mineralization of lindane during the tests. Between 1 and 9% of the radioactivity volatilized during the tests. At the end, 23 to 66% were bound to sediments and 15 to 45% of the total activity was neither extractable by water nor by cyclohexane.
Fluctuating concentrations of organochlorine pollutants during a breeding season in two Antarctic seabirds: Adelie penguin and southern fulmar
Authors: van den Brink Nico W , van Franeker Jan A , de Ruiter-Dijkman Elze M 
Published: March 2010

Abstract
During the reproductive cycle significant fluctuations of concentrations of organochlorine pollutants were detected in blood and uropygial oil from Adélie penguins (Pygoscelis adeliae) and southern fulmars (Fulmarus glacialoides) from Hop Island, Antarctica. In the Adélie penguin, concentrations of polychlorinated biphenyls (PCBs) and dieldrin were significantly higher at the moment of egg laying, while hexachlorobenzene (HCB) and 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p′-DDE) concentrations peaked at the creche stage. Subcutaneous fat is the main pool for HCB and p,p′-DDE, while PCBs and dieldrin are also stored in the pectoral muscle. It is hypothesized that the observed differences in seasonal fluctuations in organochlorine levels are related to utilization of different storage pools by the Adélie penguins at different moments in the breeding season. In the southern fulmar the fluctuations in concentrations of HCB and p,p′-DDE can be related to changes in body mass. However, concentrations of PCBs and dieldrin did not vary significantly during the season. It seems that the two groups of compounds are governed more or less independently in the southern fulmar as well. Age-dependent accumulation of most organochlorines studied reached a steady state before the age at which both species start to breed. This allows monitoring of individual birds to analyze changes in concentrations of organochlorine pollutants in the ecosystem, without having to correct for age differences. Differences in levels of organochlorine pollutants between the Adélie penguin and southern fulmar were probably the result of differences in feeding ecology.
Degradation of chlorinated benzoic acid mixtures by plant–bacteria associations
Authors: Siciliano Steven D , Germida James J 
Published: March 2010

Abstract
Phytoremediation technologies must tolerate and degrade mixtures of contaminants, as most contaminated sites contain mixtures of compounds. This study assessed the ability of plant–bacteria associations to degrade mixtures of mono- and dichlorinated benzoic acids. Sixteen forage grasses and combinations of these grasses with several bacterial inoculants were screened for growth in soil contaminated with various concentrations of mono- or dichlorinated benzoic acids. Dahurian wild rye (Elymus dauricus) inoculated with a combination of Pseudomonas aeruginosa strain R75 and Pseudomonas savastanoi strain CB35 reduced 3-chlorobenzoic acid (3CBA) levels in soil by 74% (i.e., 583 to 149 mg/kg). Meadow brome (Bromus biebersteinii) inoculated with Alcaligenes sp. strain BR60 reduced 2,3-dichlorobenzoic acid (23diCBA) levels in soil by 56% (i.e., 125 to 55 mg/kg). Altai wild rye (Elymus angitus) inoculated with strains R75 and CB35 reduced 2,5-dichlorobenzoic acid (25diCBA) levels in soil by 46% (i.e., 211 to 113 mg/kg). Two plant–bacteria associations and uninoculated Dahurian wild rye also degraded mixtures of 3CBA, 23diCBA, or 25diCBA. When 25diCBA was mixed with 23diCBA, uninoculated Dahurian wild rye reduced levels of 25diCBA in soil by 31% and reduced the levels of both 25diCBA and 3CBA by up to 64% when these two contaminants were present in a mixture. Similarly, meadow brome inoculated with BR60 reduced 23diCBA and 3CBA levels by up to 50%. Levels of all three chlorinated benzoic acids were reduced by 53 to 63% by Altai wild rye inoculated with strains R75 and CB35. Our results indicate that plant–bacteria associations can tolerate and degrade mixtures of contaminants in soil but that predictions about phytoremediation of mixed contaminants may not be straightforward.
Behavioral and histopathological effects of fluoranthene on bullfrog larvae (Rana catesbeiana)
Authors: Walker Sean E , Taylor Douglas H , Oris James T 
Published: March 2010

Abstract
The goals of this study were to use behavioral and histopathological endpoints to examine the sublethal effects of fluoranthene exposure in conjunction with solar ultraviolet radiation on bullfrog larvae. Exposure to fluoranthene and simulated solar ultraviolet radiation for 48 h caused a significant effect on locomotor behavior at 60 μg fluoranthene/L. At 96 h, however, hyperactivity was noted in the 40-μg fluoranthene/L exposure. The skin of bullfrog larvae was sensitive to the phototoxic effects of fluoranthene. Following exposure to sublethal levels of fluoranthene (10 μg fluoranthene/L) there were signs of necrosis as well as structural alterations in the skin when examined using light microscopy. Based on these results, the photoinduced toxicity of fluoranthene, and hence other phototoxic polycyclic aromatic hydrocarbons, pose a potential hazard to ranid larvae well within the water solubility limits of the compound.
Vertical distribution of acid-volatile sulfide and simultaneously extracted metals in a recent sedimentation area of the river Meuse in the Netherlands
Authors: van den Berg Gerard A , Loch J P Gustav , van der Heijdt Lambertus M , Zwolsman John J.G 
Published: March 2010

AbstractThe bioavailability of heavy metals in sediments may be strongly decreased by the presence of AVS (acid-volatile sulfide). In contaminated freshwater sediments, however, AVS levels may not be sufficiently high to scavenge all reactive heavy metals. In different seasons, the vertical distribution of AVS and SEM (simultaneously extracted metals) was studied in sediment cores of a recent sedimentation area of the river Meuse. In the suboxic layer of the sediments, the amount of AVS is always too low to bind all reactive metals as sulfides (SEM/AVS &gt; 1). SEM/AVS decreases with depth in the sediments, going from ratios higher than one in the surface sediments to ratios on the order of one or even less than one at greater depths. This large vertical variation in AVS levels is attributed to diagenetic processes i.e., sulfide oxidation in the suboxic top layer and sulfate reduction in the underlying anoxic sediment layer. The depth of the boundary between the suboxic and the anoxic layer changes seasonally. An important implication of these findings is that SEM/AVS ratios in mixed homogenized sediment samples are generally not suited for the assessment of potential metal toxicity of sediments.
Polycyclic aromatic hydrocarbons in sediments and mussels of the western Mediterranean sea
Authors: Baumard Pascale , Budzinski Hélène , Garrigues Philippe 
Published: March 2010

Abstract
The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in superficial sediments and mussels (Mytilus galloprovincialis) of the western Mediterranean sea (French Riviera, Corsica, Sardinia). The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). The PAH concentrations ranged from 1 to 20,500 ng/g in the sediments. Different molecular indices allowed differentiation between the different pollutant sources. On the French coast, PAHs originated mainly from incomplete combustion of organic matter (pyrolytic origin), whereas for some sites in Corsica and Sardinia an overimposition of petrogenic PAHs occurred. The mussel PAH concentrations ranged from 25 to 390 ng/g. The total and individual PAH bioaccumulation factors were calculated. The correlation between sediment and mussel PAH content was discussed in terms of bioavailability. It was possible to distinguish different absorption routes for the xenobiotics according to their physicochemical properties. Because the mussel distribution of phenanthrene and anthracene seems to be governed by their water solubility, these compounds were probably mainly absorbed as the water-dissolved form, whereas the heavier molecular weight PAHs (more than four aromatic rings), whose sediment and mussel concentrations are correlated with higher correlation coefficients than for phenanthrene and anthracene, were probably mainly absorbed as adsorbed on particles. Furthermore, a possible preferential biotransformation of benzo[a]pyrene over benzo[e]pyrene is discussed.