bluuebunny/crossref_metadata_2025_split huggingface dataset:
A methodology for inferring the causes of observed impairments in aquatic ecosystems
Authors: Suter Glenn W. , Norton Susan B. , Cormier Susan M. 
Published: March 2010

Abstract
Biological surveys have become a common technique for determining whether aquatic communities have been injured. However, their results are not useful for identifying management options until the causes of apparent injuries have been identified. Techniques for determining causation have been largely informal and ad hoc. This paper presents a logical system for causal inference. It begins by analyzing the available information to generate causal evidence; available information may include spatial or temporal associations of potential cause and effect, field or laboratory experimental results, and diagnostic evidence from the affected organisms. It then uses a series of three alternative methods to infer the cause: Elimination of causes, diagnostic protocols, and analysis of the strength of evidence. If the cause cannot be identified with sufficient confidence, the reality of the effects is examined, and if the effects are determined to be real, more information is obtained to reiterate the process.
Inhibition of digestive enzyme activities by copper in the guts of various marine benthic invertebrates
Authors: Chen Zhen , Mayer Lawrence M. , Weston Donald P. , Bock Michael J. , Jumars Peter A. 
Published: March 2010

AbstractDigestive systems of deposit and suspension feeders can be exposed to high concentrations of copper (Cu) by ingestion of contaminated sediments. We assessed a potential impact of this Cu exposure on digestive enzyme activities in a wide range of benthic organisms by monitoring enzyme activities in their gut fluids during in vitro titrations with dissolved Cu, which mimics Cu solubilization from sediments. Increasing Cu inhibited digestive protease activities at threshold values, which varied widely among organisms, from 8 μM for an echinoderm to 0.4 M for an echiuran. More Cu was required to inhibit proteases in guts containing higher amino acid concentrations because strong Cu-binding sites on amino acids prevent Cu interaction with the enzymatically active sites. Threshold Cu concentrations were similar for proteases, esterases, lipases, and α- and β-glucosidases, suggesting the same inhibition mechanism. Copper was less effective at inhibiting enzymes at lower pH, suggesting that protons can compete with Cu ion for binding to enzymatically active sites or that enzyme conformation is less vulnerable to Cu inhibition at lower pH. These results lead to the counterintuitive conclusion that deposit feeders with low enzyme activity, low amino acid concentration, and high pH values are most vulnerable to harm from sedimentary Cu by this mechanism, although they solubilize less sedimentary Cu than their counterparts with high enzyme activity, high amino acid concentrations, and low gut pH. In general, digestive systems of echinoderms may therefore be more susceptible to Cu contamination than those of polychaetes, with various other phyla showing intermediate susceptibilities. If threshold Cu values are converted to solid-phase sedimentary Cu concentrations, the thresholds are at least consistent with Cu loadings that have been observed to lead to biological impacts in the field.
Evaluation of the effect of reactive sulfide on the acute toxicity of silver (I) toDaphnia magna. Part 2: Toxicity results
Authors: Bianchini Adalto , Bowles Karl C. , Brauner Colin J. , Gorsuch Joseph W. , Kramer James R. , Wood Chris M. 
Published: March 2010

AbstractThe protective effect of reactive sulfide against AgNO3 toxicity to Daphnia magna neonates was studied. Acute (48-h) toxicity tests were performed in the absence (&lt;5 nM) and presence of low (∼25 nM) and high (∼250 nM) concentrations of zinc sulfide clusters under oxic conditions. In both the presence and the absence of sulfide, lower mean lethal concentration (LC50) values were observed when measured as opposed to nominal silver concentrations were used in calculations. This reflected the fact that measured total silver concentrations were lower than nominal concentrations due to losses of silver from solution observed during the experiment. High concentration (∼250 nM) of sulfide completely protected against toxicity up to the highest silver concentration tested (2 μg/L [19 nM]) with measured silver data. In the presence of environmentally realistic levels of sulfide (∼25 nM) in receiving waters, acute silver toxicity was reduced by about 5.5-fold. However, when filtered (0.45 μm) silver concentrations alone were considered, toxicity (48-h LC50) was similar in the absence (0.22 μg/L) and presence (0.28 μg/L) of sulfide. The difference between measured total and filtered silver was attributed to chemisorption of the metal sulfide onto the membrane filter and provides evidence that the toxic fraction of silver is that which is unbound to sulfide. Accumulation of silver was greater in daphnids exposed to silver in the presence of sulfide than in its absence, even though a toxic effect was not observed under these conditions. In this case, silver appears to be incorporated by daphnids rather than merely adsorbed on the surface. Our results point out the need to incorporate sulfide into the acute biotic ligand model and to assess its potentially large role in preventing chronic toxicity.
Accumulation and elimination of lanthanum by duckweed (Lemna minorL.) As influenced by organism growth and lanthanum sorption to glass
Authors: Weltje Lennart , Brouwer Anke H. , Verburg Tona G. , Wolterbeek Hubert Th. , de Goeij Jeroen J. M. 
Published: March 2010

AbstractLanthanide emissions to the environment increase as a result of the growing industrial applications of these elements. However, robust data to evaluate the environmental fate of lanthanides are scarce. This article describes the accumulation and elimination of lanthanum (La) by common duckweed (Lemna minor L.). Speciation modeling was performed to assure that solubility products were not exceeded. It also showed that La was predominantly associated with ethylenediaminetetraacetic acid (EDTA). Lanthanum concentrations in plants and medium and the amounts sorbed to glass vessels were quantified by using the radioisotope 140La. The amount of La adsorbed on the glass reached values of 25% of the total La present. A model was formulated to describe La uptake in exponentially growing duckweed in the presence of an adsorptive surface. Growth-induced dilution appeared more efficient in lowering plant La concentrations than actual elimination. An elimination study revealed two compartments, of which the smallest eliminated 50 times faster than the bigger compartment, which eliminated mainly by growth dilution. The average bioconcentration factor was 2,000 L/kg fresh weight and 30,000 L/kg dry weight, comparable with those of other higher plants. At the applied concentration of 10 nM, no effects were observed on duckweed growth. However, the high bioconcentration factor warrants monitoring of lanthanide emissions.
Development of a Monte Carlo sampling shell for the pesticide root zone model and its application by the Federal Insecticide, Fungicide, and Rodenticide Act Environmental modeling validation Task Force
Authors: Havens Patrick L. , Carbone John P. , Warren-Hicks William , Fouch Michael A. 
Published: March 2010

Abstract
A user interface to the U.S. Environmental Protection Agency pesticide root zone model (PRZM) was constructed to allow Monte Carlo sampling of input parameter distributions. The interface was constructed employing the Visual Basic for Applications development environment, along with the functionality of the Crystal Ball Professional forecasting and risk analysis package. The tool has been utilized by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Environmental Model Validation Task Force to perform detailed statistical analyses of model input parameter uncertainty and the propagation of this uncertainty on the model outputs as well as comparisons of modeled and field-measured data.
Accumulation of heavy metals in water spinach (Ipomoea aquatica) cultivated in the Bangkok region, Thailand
Authors: Göthberg Agneta , Greger Maria , Bengtsson Bengt-Erik 
Published: March 2010

Abstract
The aquatic plant water spinach (Ipomoea aquatica), either wild or cultivated, is found throughout Southeast Asia and is a widely consumed vegetable in the region. Many of the waters where I. aquatica grows serve as recipients for domestic and other types of wastewater. Because these waters contain not only nutrients, but often also a wide variety of pollutants such as heavy metals from various human activities, many people risk intoxication. To estimate the accumulation of lead (Pb), cadmium (Cd), total mercury (total Hg), and methylmercury in I. aquatica and the potential hazard to human health via consumption, nine sites for cultivation of I. aquatica in the greater Bangkok region of Thailand were sampled. At seven of the sites, I. aquatica was cultivated for the local food market. The concentrations of methylmercury, total Hg, Pb, and Cd in I. aquatica were 0.8 to 221, 12 to 2,590, 40 to 530, and ≤10 to 123 μg/kg dry weight, respectively. At all sites at least one element showed relatively high concentrations and no reference site could be established. From threshold values for highest tolerable intake of these metals by humans and information about consumption of I. aquatica among local people, Pb and Cd concentrations in I. aquatica do not seem to be a direct threat to human health. However, concentrations of Hg were very high at some sites, and were higher in leaves (highest mean value: 1,440 μg/kg dry wt) than in stems (highest mean value: 422 μg/kg dry wt). This might be a threat, especially to children and fetuses, because Hg in I. aquatica was composed of methylmercury, partly or totally, at most sites to 11% or less and at one site from 50 to 100%. At the latter site, I. aquatica was not cultivated for the food market. Because other food sources, such as fish, may have high concentrations of methylmercury, these results indicate a need for monitoring of Hg, especially methylmercury, in different foodstuffs in the region.
Acute and chronic toxicity of nickel to marine organisms: Implications for water quality criteria
Authors: Hunt John W. , Anderson Brian S. , Phillips Bryn M. , Tjeerdema Ron S. , Puckett H. Max , Stephenson Mark , Tucker David W. , Watson Daniel 
Published: March 2010

AbstractAcute and chronic toxicity tests were conducted to determine the effects of nickel on three U.S. west coast marine species: a fish (the topsmelt, Atherinops affinis), a mollusk (the red abalone, Haliotis rufescens), and a crustacean (the mysid, Mysidopsis intii). The 96-h median lethal concentration (LC50) for topsmelt was 26,560 mg/L, and the chronic value for the most sensitive endpoint in a 40-d exposure was 4,270 mg/L. The median effective concentration (EC50) for 48-h abalone larval development was 145.5 μg/L, and the chronic value for juvenile growth in a 22-d exposure through larval metamorphosis was 26.43 mg/L. The mysid 96-h LC50 was 148.6 μg/L, and the chronic value for the most sensitive endpoint in a 28-d, whole life-cycle exposure was 22.09 μg/L. The abalone and mysid acute values were lower than other values available in the literature. Acute-tochronic ratios for nickel toxicity to the three species were 6.220, 5.505, and 6.727, respectively, which were similar to the only other available saltwater value of 5.478 (for Americamysis [Mysidopsis] bahia) and significantly lower than the existing values of 35.58 and 29.86 for freshwater organisms. Incorporation of data from the present study into calculations for water quality criteria would lower the criterion maximum concentration and raise the criterion continuous concentration for nickel.
Application of sewage sludge to arable land–soil concentrations of polybrominated diphenyl ethers and polychorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls, and their accumulation in earthworms
Authors: Matscheko Nadja , Tysklind Mats , de Wit Cynthia , Bergek Sture , Andersson Rolf , Sellström Ulla 
Published: March 2010

Abstract
Soils from five agricultural sites, three research sites, and two privately owned farms were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polybronimated diphenylethers (PBDEs). In soils that had not been treated with sludge (reference soils), the international toxic equivalents (I-TEQs) were 0.6 to 1.5 pg/g dry matter (DM) for the PCDD/Fs, which are low compared to generally reported background soil levels in Europe. The concentrations of sum of six penta- and hexa-PCBs were 450 to 1,400 pg/g DM. The PBDEs 47 and 99 dominated among the tri- to hepta-PBDEs analyzed (8–80 pg/g DM). The impact of adding 1 to 3 tonnes of sludge (DM) per hectare per year on the concentrations was studied at the three research sites by calculating ratios of the compounds in sludge-treated soil to reference soil (S/R ratio). The concentrations of I-TEQs did not increase in the sludge-treated soil, whereas the S/R ratios for PBDEs were greater than one. Also, although the PCB contents were higher in the sludge-treated soils, the background sources were more important for the concentrations of PCBs than of PBDEs. The largest increase in the S/R ratios was found at a private farm where large amounts of sludge had been used in the past. Accumulation of the compounds in earthworms from the sites also was investigated. The biota-soil accumulation factors (BSAFs) of the tested compounds declined in the following order: ortho-PCBs ∼ PBDEs &gt; non-ortho-PCBs &gt; 2,3,7,8-substituted PCDD/Fs. The average BSAF for ortho-PCBs was five (organic matter/lipids), and the lowest BSAFs (0.1–0.8) found were for octachlorodibenzo-p-dioxin. To our knowledge, accumulation of PBDEs in earthworms has not been published previously.
Toxicity of aqueous and sediment-associated fluoride to freshwater organisms
Authors: Metcalfe-Smith Janice L. , Holtze Keith E. , Sirota Gary R. , Reid James J. , de Solla Shane R. 
Published: March 2010

AbstractInorganic fluorides were declared toxic under the Canadian Environmental Protection Act in 1993 based on their potential to cause long-term harmful effects in aquatic and terrestrial ecosystems, but information on the toxicity of sediment-associated fluoride to freshwater benthic organisms was considered incomplete. The purpose of this study was to determine the toxicity of aqueous and sediment-associated fluoride to several species of freshwater organisms and to determine if toxic effects could be expected under environmentally realistic exposures. Toxicity of fluoride (as NaF) in short-term (48–96-h) lethality tests was greatest for the amphipod Hyalella azteca (median lethal concentration [LC50] = 14.6 mg F−/L), followed by the mayfly Hexagenia limbata (32.3), the midge Chironomus tentans (124.1), the fathead minnow Pimephales promelas (262.4), and the cladoceran Daphnia magna (282.8). Relative toxicity in long-term (10–28-d) growth and survival tests in spiked sediment was similar. Hyalella azteca was the most sensitive species for growth (25% inhibitory concentration [IC25] = 290.2 μg F−/g), followed by C. tentans (661.4), H. limbata (1,221.3), and P. promelas (&gt;5,600); H. azteca was also the most sensitive species for survival (LC50 = 1,114.6 μg F−/g), followed by H. limbata (1,652.2) and P. promelas and C. tentans (&gt;5,600 for both). Concentrations of fluoride measured in sediments near some industrial point sources exceed some of these toxicity thresholds. Fluoride is highly mobile in aquatic systems and could potentially reach toxic levels in the water column during dredging to remove fluoride-contaminated sediment.
Cosolvent effects of phenanthrene sorption-desorption on a freshwater sediment
Authors: Bouchard Dermont C. 
Published: March 2010

Abstract
This study evaluated the effects of the water-miscible cosolvent methanol on the sorption-desorption of phenanthrene by the natural organic matter (NOM) of a freshwater sediment. A biphasic pattern was observed in the relationship between the log of the carbon-normalized sorption distribution coefficient (Koc) and the volumetric fraction of water-miscible cosolvent (fc), in this case methanol, that was accounted for with phenanthrene solubility data. Results also indicated that methanol elicited additional effects on phenanthrene sorption beyond the solution phase effects. The level of fc was observed to have a significant effect on sorption-desorption hysteresis, with hysteresis being greater for treatments where phenanthrene and sediment were equilibrated with methanol-phenanthrene solutions but desorbed with aqueous solutions. These results are discussed in light of the deformable pore network of the rubbery/glassy NOM polymer construct.
Induction of an estrogen-responsive reporter gene in rainbow trout hepatoma cells (RTH 149) at 11 or 18°C
Authors: Hornung MichaeL W. , Ankley Gerald T. , Schmieder Patricia K. 
Published: March 2010

AbstractThe potential for temperature to influence estrogen-mediated responses in poikilothermicanimals suggested that temperature may be an important variable to consider when using an estrogen-responsive reporter gene in a rainbow trout cell line to test chemicals for estrogenic activity. Rainbow trout hepatoma cells (RTH 149) incubated at 11 or 18°C were cotransfected with an estrogen-responsive luciferase reporter plasmid and a plasmid containing a constitutively expressed rainbow trout estrogen receptor. The RTH-149 cells were then exposed to estradiol, with samples collected at 24-h intervals. The 72-h effective concentration for 50% maximal response (EC50) for estrogen-responsive luciferase activity at 11°C was 3.8 × 10−9 M and 7.4 × 10−10 M at 18°C. The efficacy of estradiol was lower at 11°C. The maximal response to estradiol in cells at 11°C was generally two- to threefold greater than controls (mean = 2.6-fold), whereas the maximal response at 18°C was three- to fourfold greater than controls (mean = 3.2-fold). Ethinylestradiol, a strong estrogen receptor agonist, was similar to estradiol in potency (relative potency = 0.8) and efficacy at the two temperatures. The EC50 of the weak estrogen receptor agonist 4-tert-pentylphenol was 7.6 × 10−7 M at 11°C and 6.9 × 10−7 M at 18°C; its potency relative to 17β-estradiol was not significantly different at the two temperatures, 0.00036 and 0.00054 at 11°C and 18°C, respectively. The estrogen-responsive reporter gene activity produced by 10−8 M estradiol was completely inhibited by the two estrogen hormone receptor antagonists, ZM 189,154 and ICI 182,780, at 10−6 M concentration of either antagonist. Although there may be slight differences in responses between the two temperatures tested here, this assay can be used to effectively determine the relative estrogenic activity of chemicals within the physiological temperature range of rainbow trout.
Polycyclic aromatic hydrocarbons and black carbon in sediments of a remote alpine Lake (Lake Planina, northwest Slovenia)
Authors: Muri Gregor , Wakeham Stuart G. , Faganeli Jadran 
Published: March 2010

Abstract
Polycyclic aromatic hydrocarbons (PAH) and black carbon (BC) were measured in alpine Lake Planina (Slovenia) sediment. Lake Planina is a remote mountain lake with almost no direct anthropogenic influence. Long-distance atmospheric deposition is a major pathway for the loading of contaminants to the sediment. The PAH were analyzed by gas chromatography coupled to mass spectrometry, whereas the BC was determined by thermal oxidation method. A flux of PAH to surface sediments of approximately 1,100 μg m−2 year−1 was obtained and was higher than that in other alpine lakes of the central European Alps. However, surface sediment PAH concentration, normalized to organic carbon content (OC), amounted to 5 μg PAHpyr/g OC and showed that Lake Planina is relatively equally exposed to atmospheric pollution compared with other lakes in the region. The BC:OC ratios ranged from 3 to 8% (w/w). In addition, a huge forest fire occurred in 1948 in the lake's surrounding area, which is recorded in the sediment. Both PAH and BC distributions were affected by the fire in 1948 in the lake's watershed, because their concentration increased remarkably. The concentration of retene, a molecular marker of coniferous wood combustion, increased to 1,000 ng/g dry weight sediment at the sediment interval corresponding to approximately the year 1950.
Toxicity of chemicals to microalgae in river and in standard waters
Authors: Graff Lionel , Isnard Pascal , Cellier Pierre , Bastide Jean , Cambon Jean-Pierre , Narbonne Jean-Francois , Budzinski Helene , Vasseur Paule 
Published: March 2010

Abstract
The influence of the composition of natural waters on the toxicity of chemicals to microalgae was studied on samples representative of western European rivers. Effects of zinc, pentachlorophenol (PCP), 4-nonylphenol (4-NP), phosalone, and 2,4,5-trichloroaniline (TCA) on algal growth were tested in river waters without adding any nutrients or cosolvents, and in the International Standards Organization (ISO) medium for comparison. The mean values of effective concentrations reducing the algal growth by 50% (EC50s) after 72 h based on measured concentrations did not differ significantly in natural waters and in standard medium for 4-NP (0.5 mg/L) and phosalone (0.8–0.9 mg/L). These values were two or three times higher in rivers than in ISO medium for PCP (0.25 vs 0.1 mg/L), TCA (1.69 vs 0.73 mg/L), and zinc (0.20 vs 0.056 mg/L). Although the mean values were of the same order of magnitude, the distribution of the EC50 values ranged over 1.5 and 2 log concentrations in surface waters. Therefore, in view of a refined hazard assessment of a chemical on a local scale, it would be advisable to use the actual river water of the concerned aquatic environment in testing. Correlations between toxicity data and the physicochemical characteristics of the waters identified classic parameters such as water hardness or conductivity as factors that significantly influenced the toxicity of the ionizable compounds PCP and zinc. On the other hand, organic materials or suspended solids, but only at high levels, affected the toxicity of 4-NP, an organic chemical with high adsorption potential. No correlation could be drawn for phosalone and TCA.