bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of copper on immune system parameters of rainbow trout (Oncorhynchus mykiss)
Authors: Dethloff Gail M , Bailey Howard C 
Published: March 2010

AbstractAricultural, urban, industrial, and mining sources release metals into waterways. The effects of sublethal concentrations of metals on integrated physiological processes in fish, such as immunocompetency, are not well understood. The objective of this study was to determine the physiological effects of a range of sublethal copper concentrations (6.4, 16.0, and 26.9 μg Cu/L) on Shasta-strain rainbow trout (Oncorhynchus mykiss) exposed in soft water. Trout were sampled after 3, 7, 14, and 21 d of exposure to copper. The percentage of monocytes was consistently elevated at 26.9 μg Cu/L, and the percentage of lymphocytes was decreased. A consistent increase in the percentage of neutrophils occurred at 26.9 and 6.4 μg Cu/L. Respiratory burst activity was decreased for all concentrations at all sampling days, but a significant reduction occurred only at 14 and 21 d of exposure to copper. B-like cell proliferation was decreased by exposure to the higher copper concentrations. Proliferation results, however, had high variability. T-like cell proliferation and phagocytosis were not altered. Hepatic copper concentration was consistently elevated in trout exposed to 26.9 μg Cu/L; no correlation was found between hepatic copper concentration and the immune system responses investigated. Consistent alterations in immunological parameters suggest that these parameters could serve as indicators of chronic metal toxicity in natural systems.
Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor
Authors: Fairchild James F , Ruessler D Shane , Carlson A Ron 
Published: March 2010

AbstractThis study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin &gt; atrazine &gt; alachlor &gt; metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum &gt; Najas &gt; Elodea &gt; Lemna &gt; Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum &gt; Chlorella &gt; Chlamydomonas &gt; Microcystis &gt; Scenedesmus &gt; Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.
Recovery of brain acetylcholinesterase and plasma cholinesterase activities in quail (Coturnix coturnix) after chlorpyriphos administration and effect of pralidoxime treatment
Authors: Soler-Rodriguez Francisco , Miguez-Santiyan Maria-Prado , Reja-Sanchez Antonio , Roncero-Cordero Vicente , Garcia-Cambero Jesus-Pablo 
Published: March 2010

Abstract
Chlorpyriphos (13 mg/kg) was administered to quail (Coturnix coturnix), and the responses of brain acetylcholinesterase (AChE) and plasma cholinesterase (ChE) were studied. Both enzymes responded rapidly, and the maximal inhibition (76.6 and 86.1%, respectively) ocurred 8 h postadministration. Plasma ChE recovered rapidly, and even on day 4, ChE values of quail that had received chlorpyriphos were higher than those of controls. The recovery of brain AChE activity was slower than that of plasma; it reached 59% of controls 2 d after chlorpyriphos administration, then it recovered slowly, and only at day 11 was its level not depressed with respect to controls. This recovery followed the logarithmic pattern Y = a + b(log X), where Y is the AChE activity expressed as the percentage with respect to controls and X is the day after dosing, giving a significant correlation (r = 0.9746, p &lt; 0.001 when using group means and r = 0.9219, p &lt; 0.001 when using individual values). No clinical signs or mortality were observed, and histopathological observations in the central nervous system (encephalytic reaction, necrotic Purkinje cells), liver (congestion, vacuolation), and kidney (congestion, nephrosis) were not severe and did not endanger the life of the quail. Sixteen hours after chlorpyriphos administration, some quail were treated with pralidoxime, which significantly reactivated brain AChE but not plasma ChE. However, this effect did not last for the rest of the experiment; because no signs of toxicosis appeared, the experiment was not repeated.
Action of resin acids in nerve ending fractions isolated from fish central nervous system
Authors: Zheng Jian , Nicholson Russell A 
Published: March 2010

AbstractThe actions of three resin acids (abietic acid, dehydroabietic acid, and 12,14-dichlorodehydroabieticacid) were investigated using synaptosomes isolated from the whole brain of the rainbow trout (Oncorhynchus mykiss). Exposure of synaptosomes to resin acids caused a concentration-dependent increase in synaptosomal free [Ca2+] that was unaffected by tetrodotoxin. 12,14-Dichlorodehydroabietic acid (EC50 = 12 μM) was five- to sixfold more potent as a calcium mobilizing agent compared to its nonchlorinated analog dehydroabietic acid (IC50 = 68 μM) and maximum increases in synaptosomal free [Ca2+] were estimated at approximately 325 nM and 260 nM, respectively. Although closer to dehydroabietic acid in potency, abietic acid was more efficacious, increasing synaptosomal free [Ca2+] by 500 nM at 133 μM. The requirement for extracellular Ca2+ was greatest for dehydroabietic acid compared to abietic acid or 12,14-dichlorodehydroabietic acid; however, none of the study compounds was capable of stimulating 45Ca2+ uptake or reducing 45Ca2+ efflux from synaptosomes. For 12,14-dichlorodehydroabietic and dehydroabietic acids only, the rises in synaptosomal free [Ca2+] were accompanied by significant reductions in synaptosomal adenosine triphosphate levels and increases in synaptosomal oxygen consumption. Electron microscopic studies have shown that the vesicular content of synaptosomes was dramatically reduced by treatment with all three study compounds. Our investigation suggests that resin acids have a strong calcium mobilizing action in nerve endings isolated from fish brain and chlorination increases potency. We postulate that resin acids mobilize Ca2+ from intracellular stores to facilitate neurotransmitter release and that for dehydroabietic acid (and to a lesser extent for abietic and 12,14-dichlorodehydroabietic acids), extracellular calcium is required for efficient penetration of the plasma membrane. The bioenergetic and respiratory disruption we observe is not closely linked to changes in cytosolic free [Ca2+].
Elemental fish tissue contamination in Northeastern U.S. Lakes: Evaluation of an approach to regional assessment
Authors: Yeardley Roger B , Lazorchak James M , Paulsen Steven G 
Published: March 2010

Abstract
The approach of the Environmental Monitoring and Assessment Program (EMA) to monitoring of fish tissue contaminants is shown to have utility for regional assessment, and for discrimination of regional from local contamination. The survey sampling design employed by EMAP can be used to make regional assessments without conducting a complete resource inventory. The Environmental Monitoring and Assessment Program—Surface Waters conducted a survey of 167 lakes in the northeastern United States during 1992 through 1994 and analyzed whole fish composite samples for contaminants, including Al, As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, and Zn. Using fish tissue contaminant consumption risk levels derived from U.S. Environmental Protection Agency hazard assessment models, methylmercury (MeHg) was determined to be the elemental contaminant of regional concern to fish consumers: 26% of lakes contained fish with MeHg exceeding a human critical value of 0.2 μg/g; 54 and 98% of lakes contained fish with MeHg exceeding wildlife critical values for piscivorous mammals (0.1 μg/g) and birds (0.02 μg/g), respectively. The other elements analyzed appeared to be at safe levels on a regional scale, or only of localized concern with regard to human health.
Accumulation of metals, polycyclic (halogenated) aromatic hydrocarbons, and biocides in zebra mussel and eel from the rhine and meuse rivers
Authors: Hendriks A Jan , Pieters Henk , de Boer Jacob 
Published: March 2010

AbstractConcentrations of heavy metals and various groups of organic microcontaminants were measured in zebra mussel and eel from the Rhine–Meuse basin. Residues in mussel from the Rhine and Meuse were on average 2.3 and 2.9 times higher than in those from the reference location of IJsselmeer. Total body burdens of organic microcontaminants in mussel and eel varied between 0.05 to 0.07 mmol/kg fat weight in six out of seven samples. The largest contribution in mussels and eel came from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), respectively. Concentrations of bromodiphenylethers, chlorobenzenes, chloronitrobenzenes, chloroterphenyls, and chlorobenzyltoluenes were lower. Total polybrominated biphenyl residues appear lower than total PCB levels. The largest chlorobiocide residues were noted for 4,4′-DDE, toxaphene, trichlorophenylmethane, and γ-hexachlorocyclohexane. An extraordinary high body burden of 1.2 mmol/kg fat weight, largely consisting of acenaphthene, was observed in one sample. Ratios of concentrations in organism fat and dry organic suspended solids varied between 1 and 10 for traditionally monitored organochlorines, independent of the octanol–water partition coefficient (Kow; for Kow &lt; 106). The values did not deviate significantly from a value of about 3.3, expected for equilibrium partitioning of persistent chemicals. Lower values were observed for PAHs and some chloro(nitro)benzenes. Most ratios of concentrations in eel and mussel fat were within the range of 1 to 10, also largely independent of Kow. Yet, values tended to be higher at Kow &gt; 106. Ratios below 1 were noted for pentabromodiphenylether, pentachloro(thio)anisol, chlorobenzyltoluenes, and some chloronitrobenzenes, chlorobiphenyls, and chlorobiocides. These field data confirm recent modeling efforts on bioconcentration and biomagnification. For heavy metals, atomic mass explained 67% of the variation in zebra mussel residues.
Sorption coefficients of polycyclic aromatic hydrocarbons for two lake sediments: Influence of the bactericide sodium azide
Authors: de Maagd P Gert-Jan , Sinnige Theo L , Schrap S Marca , Opperhuizen Antoon , Sum Dick T.H.M 
Published: March 2010

Abstract
Sorption coefficients (Kps) of a series of polycyclic aromatic hydrocarbons (PAHs) were determined in two Dutch freshwater lake sediments to improve the insight into sorption in the aquatic environment. The influence of experimental factors, such as compound concentration, equilibration time, and influence of a bactericide on Kp, was studied. No significant influence of compound concentration on Kp was found. A contact time of 48 h was sufficient to reach equilibrium between PAHs in the sediment and water phase. In the absence of the bactericide, sodium azide, incomplete mass balances, and high Kp of low molecular weight PAHs were found that were not caused by volatilization from, photodegradation in, or sorption by the test system. In the presence of sodium azide, however, high mass balances and lower Kp were found for these compounds. This suggested that significant biodegradation of these compounds occurred in the water phase in the absence of sodium azide. The organic carbon-normalized sorption coefficients (Koc) of the PAHs in Lake Oostvaardersplassen were two to three times higher than those in Lake Ketelmeer sediment. Although Koc of the PAHs differed for the two sediments, a clear relationship was found between Koc and the octanol/water partition coefficient for both sediments and between the Koc of both sediments. In conclusion, the methodology to determine Kp of biodegradable compounds should include the prevention of bacterial activity, e.g., by addition of sodium azide. Sorption of PAHs in the Dutch lake sediments is determined by the hydrophobicity of the PAH, the organic carbon content of the sediment, and one or more unspecified sediment-specific characteristics.
Wet deposition of current-use pesticides in the Sierra Nevada mountain range, California, USA
Authors: McConnell Laura L , LeNoir James S , Datta Seema , Seiber James N 
Published: March 2010

Abstract
Atmospheric inputs of pesticides transported from California's Central Valley to the Sierra Nevada mountains (California, USA) were investigated by collecting winter-spring precipitation (rain and snow) from Sequoia National Park and from the Lake Tahoe basin. Pesticides currently used in California's Central Valley were detected in snow and rain samples from two elevations in Sequoia National Park (SNP) in the southern Sierras. At the lower elevation site (533 m), chlorothalonil was present at the highest levels (&lt;0.4–85 ng/L), followed by malathion (&lt;0.046–24 ng/L), diazinon (&lt;0.21–19 ng/L), and chlorpyrifos (1.3–4.4 ng/L). At 1,920 m elevation, chlorothalonil was also present at the highest levels (&lt;0.57–13 ng/L) followed by diazinon (&lt;0.057–14 ng/L), chlorpyrifos (1.1–13 ng/L), and malathion (&lt;0.045–6 ng/L). Trifluralin, α- and γ-hexachlorocyclohexane (HCH), and α-and β-endosulfan were also detected at both locations and at lower concentrations, generally ranging from 0.5 to 2 ng/L. In the Lake Tahoe basin, elevation 2,200 m, malathion was also found in snow at concentrations ranging from &lt;0.046 to 18 ng/L, as was diazinon (&lt;0.057–7 ng/L), chlorpyrifos (0.30–3.4 ng/L), and chlorothalonil (0.66–1.7 ng/L). Chlorothalonil, chlorpryifos, α-and γ-HCH, and α-endosulfan were found in surface and deep water samples at two locations in Lake Tahoe and at concentrations similar to those found in snow within the lake basin. Lake Tahoe basin snow samples in general had lower concentrations than those from SNP. This difference in concentration levels reflects the closer proximity of downwind pesticide usage to SNP than the Lake Tahoe basin. An estimated annual loading of one chemical, chlorpyrifos, of 24 to 31 kg/year was made for the SNP land area. Comparisons of observed concentrations were made with reported aquatic toxicity and water criteria levels.
Comparison of toxicities and mechanism of action ofn-alkanols in the submitochondrial particle and theVibrio fischeribioluminescence (Microtox®) bioassay
Authors: Gustavson Karl E , Svenson Anders , Harkin John M 
Published: March 2010

AbstractMany studies on the toxicity of n-alkanols have been conducted and quantitative structure-activity relationships (QSARs) established comparing bioassay toxicity data to carbon number. The results typically indicate increasing toxicity with increasing n-alkanol chain length, but often higher homologues are not assessed, where toxicity no longer increases with carbon number—a phenomenon commonly called the cutoff effect. The mode of toxic action of these compounds has been designated narcosis I; however, the specific mechanism is unknown and widely debated. This study compares results for two commonly used bioassays, the submitochondrial particle (SMP) and the Microtox® bioassay, for the homologous series of n-alkanols ranging from methanol (C1-OH) to stearyl alcohol (C18-OH). Analysis of dose-response curve slopes indicates that the SMP assay exhibits a general mechanism of toxicity, whereas the Microtox assay exhibits this general mechanism to short-chain alkanols, but subsequently switches to specific interaction with the higher alkanols. This specific interaction is likely competitive inhibition of the bacterial luciferase. Comparison of the toxicities in these assays with octanol/water partition coeffients (Kow), the results of whole-organism tests, and a bacterial luciferase assay further substantiate this claim and indicate that the SMP is a better model of toxicity in whole organisms.
Volatilization of extensively dechlorinated polychlorinated biphenyls from historically contaminated sediments
Authors: Bushart Sean P , Bush Brian , Barnard Edward L , Bott Amelie 
Published: March 2010

Abstract
A study was conducted as a preliminary characterization of the ability of Aroclor® 1248 polychlorinated biphenyl (PCB)-contaminated sediments to volatilize PCBs into the air upon drying under conditions meant to be environmentally relevant. Sediments collected from the St. Lawrence River contained high levels (-600 ppm) of PCBs. The PCB contamination consisted of high levels of mainly ortho-substituted mono- and dichlorobiphenyls, suggesting that the original contamination had been transformed by microbial reductive dechlorination. These sediments lost 0.07 to 1.7% of their total PCB content to the air during a 24-h drying cycle. Sediments with varying amounts of overlying water (40 g of sediment with 25-100 ml of water) lost significantly less PCB to the air within the first few cycles than native sediments with no overlying water. Losses due to PCB volatilization were well correlated to sediment PCB concentration and water loss but not to drying temperatures (4–43°C) within 24-h drying cycles. The PCB congeners (mostly ortho-substituted mono-, di-, and trichlorobiphenyls) representing &gt;90% of those volatilized within the first 24 h of drying were those produced in the sediment samples as a result of microbial reductive dechlorination of the original Aroclor 1248 contamination. The presence of these congeners in volatilized air samples was positively confirmed by gas chromatography-mass spectrometry with Fourier transform infrared detection (FTIR). These results strongly suggest that significant amounts of mono-, di-, and trichlorobiphenyls may be volatilized from Aroclor 1248-contaminated sediments at ambient environmental conditions and that this PCB volatilization may be enhanced by microbial reductive dechlorination.
Structural requirements for anaerobic biodegradation of organic chemicals: A fragment model analysis
Authors: Rorije Emiel , Peijnenburg Willie J.G.M , Klopman Gilles 
Published: March 2010

AbstractA computer-automated structure evaluation program (MCASE) has been used to analyze rates of aquatic anaerobic biodegradation of a set of diverse organic compounds, and a predictive model for this endpoint has been developed. The model was evaluated in terms of possible anaerobic metabolic steps. The most important fragments linked to biodegradability (biophores) were aromatic and aliphatic thiol, methoxy, and alcohol groups and the carboxylic ester group. Fragments that can possibly inhibit anaerobic biodegradation were also identified but were not significant. A metabolic transformation step is proposed for all identified fragments. Our results are therefore such that the most likely transformation under anaerobic conditions is anticipated when biophores are present in the molecule, while nonbiodegradability is assumed when none of these fragments are present. The number of correct classifications by the model is over 93%. When predictions for all compounds were generated using cross-validation of the model, 84% of the overall predictions were correct. However, when only the predictions of possible biodegradability under anaerobic conditions are considered, the number of correct predictions is over 89%, whereas the percentage of correct predictions for nonbiodegradability is only 64%. It is therefore concluded that the analysis given in this contribution yields a model that can predict anaerobic biodegradability, but the assumption that the absence of a biophore leads to nonbiodegradability is not valid. Predictions of nonbiodegradability of compounds are therefore unreliable, probably due to the limited amount of data on anaerobic biodegradation available for use in this study.
Fluctuating asymmetry and mentum gaps in populations of the midgeChironomus riparius(diptera: Chironomidae) from a metal-contaminated river
Authors: Groenendijk Dick , Zeinstra Lidy W.M , Postma Jaap F 
Published: March 2010

AbstractThe developmental stability of both metal-exposed and nonexposed Chironomus riparius populations from the lowland River Dommel was investigated using fluctuating asymmetry (FA) and the incidence of mentum gaps. It was hypothesized that larval development was affected by the influx of metals, directly by chemical stress, as well as through inbreeding of metal-adapted and nonadapted specimens. Morphological parameters were therefore assessed in field-collected larvae and in clean, laboratory-cultured, first-generation (F1) larvae. Fluctuating asymmetry values and mentum gap incidence at contaminated field sites were significantly higher than at clean, upstream locations. Furthermore, FA values of clean, laboratory-cultured F1 larvae generally fell to reference values, indicating the direct effect of metal pollution on developmental aberrations. Mentum gaps were not observed in clean F1 cultures. Slightly elevated FA values were, however, still observed in clean F1 larvae from polluted locations downstream from the metal input. This residual disturbance was thought to reflect genetic stress emerging from interbreeding between metal-adapted and nonadapted specimens. Fluctuating asymmetry and mentum gaps together serve as a useful ecotoxicological marker for metal stress and, when combined with in situ studies and F1 cultures, allow for analysis of the response of animal populations to spatial and temporal gradients in metal exposure.