bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trace metal exchange in solution by the fungicides Ziram and Maneb (dithiocarbamates) and subsequent uptake of lipophilic organic zinc, copper and lead complexes into phytoplankton cells
Authors: Phinney Jonathan T , Bruland Kenneth W 
Published: March 2010

Abstract
The fungicides Ziram and Maneb (class dithiocarbamate) are organic Zn and Mn complexes in which the trace metal is chelated to organic dithiocarbamate ligands. The resulting organic metal complex is small, neutrally charged, and lipophilic in character. Short-term uptake experiments using a coastal diatom demonstrated that these lipophilic organic Zn and Mn complexes diffuse across the lipid bilayer that constitutes the plasma membrane. In addition, Cu2+ and Pb2+ ions in seawater solution undergo exchange reactions with Zn and Mn and form lipophilic organic Cu and Pb complexes that also diffuse across the plasma membrane and into the cytosol of the cell. Intracellularly, these trace metals are thought to dissociate from the transport ligand and complex intracellular ligands. Based on these results, the presence of dithiocarbamate fungicides in surface water can inadvertantly enhance the passive uptake of a variety of toxic heavy metals from the water into microorganisms.
Photochemical Formation of volatile mercury in high Arctic lakes
Authors: Amyot Marc , Lean David , Mierle Greg 
Published: March 2010

Abstract
Formation rates of dissolved gaseous mercury (DGM were measured in three high (74 °N) Arctic lakes and one wetland. The rate of formation of DGM was controlled by (1) the intensity of solar radiation, particularly ultraviolet-B (280–320 nm) and ultraviolet-A (320–400 nm) wavebands and (2) the concentration of available photoreducible Hg(II) complexes. Additions of hydrogen peroxide and of fulvic acids did not enhance DGM formation rates in our experiments. This study illustrates that photoreduction of mercury occurs in a wide range of aquatic systems even in the high arctic where radiation levels are lower but continue for the entire day during the summer.
Bioaccumulation and metallothionein response in the asiatic clam (Corbicula fluminea) after experimental exposure to cadmium and inorganic mercury
Authors: Baudrimont Magalie , Metivaud Jacqueline , Maury-Brachet Régine , Ribeyre Francis , Boudou Alain 
Published: March 2010

Abstract
The involvement of metallothioneins (MTs) in cadmium (Cd) and inorganic mercury (Hg[II])bioaccumulation by the freshwater bivalve Corbicula fluminea was experimentally investigated after 0, 15, 30, and 45 d of exposure from the water column source. Three levels of contamination were studied for each metal: 0, 5, and 35 μg Cd/L and 0, 1.45, and 5 μg Hg/L, with two replicates per condition. Forty eight experimental units (EUs) were conducted simultaneously. The mollusks were fed twice a week by additions of phytoplanktonic algae. Quantification of MTs was done by Hg-saturation assay, using cold Hg(II). A partial purification of these proteins was conducted by gel-filtration chromatography, followed by Cd determinations in the different eluted fractions. Results at the whole organism (soft tissues) and organ or tissue group (gills, mantle, foot, visceral mass) levels show high metal concentrations, with a fourfold greater accumulation of inorganic Hg than Cd after 30 d exposure at the same concentration of 5 μg/L. Gills and visceral mass were the principal storage compartments. A significant increase in MT concentrations was revealed in these two organs after exposure to Cd: ratios between the MT concentrations in contaminated and control mollusks were 2.4 and 2.8, respectively, for 5 and 35 μg Cd/L. Cd burdens in the cytosol and in ≤18-kDa protein fractions, similar to purified mammal MTs, correspond to 30 and 14% of the total Cd accumulated in the whole organisms. No significant increase in MT biosynthesis was observed after exposure to inorganic Hg, despite the high metal concentrations in the organs.
Relative acute effects of low pH and high iron on the hatching and survival of the water mite (Arrenurus manubriator) and the aquatic insect (Chironomus riparius)
Authors: Rousch Jeffrey M , Simmons Thomas W , Kerans Billie L , Smith Bruce P 
Published: March 2010

Abstract
We investigated the relative effects of low pH and high iron on a water mite, Arrenurus manubriator and an aquatic insect, Chironomus riparius. Eggs and active stages were exposed in static renewal toxicity tests to pH 6, 5, 4, 3, and 2, made by adding sulfuric acid to reconstituted soft water, or to iron levels of 200, 400, 600, 800, and 1,000 mg/L, made by adding ferrous sulfate to soft water at pH 4. Experiments were conducted at 22°C with a 16:8-h photoperiod, and treatments were replicated three times with at least nine individuals per treatment. Data were analyzed with a logistic response function and one-way ANOVA for pH and iron tests, respectively. Egg hatching was reduced at pH 2 for midges and at pH 3 for mites. Iron had no effect on hatching for either species. Survival of midge larvae was partially reduced at pH 4, and survival of mite deutonymphs, larvae, female and male adults was reduced at pH 3. Survival of midge larvae, and mite deutonymphs and male adults was reduced at 400, 200, and 1,000 mg Fe/L, respectively. Mite female adults and larvae were unaffected by iron. Higher metabolic requirements of unfed immature stages, the gelatinous covering of mite and insect eggs, the longer incubation period of mite eggs, and the greater osmoregulatory potential of adult mites may have contributed to the differences observed.
Structural-based differences in ecotoxicity of benzoquinoline isomers to the zebra mussel (Dreissena polymorpha)
Authors: Kraak Michiel H S , Wijnands Paul , Govers Harrie A J , Admiraal Wim , de Voogt Pim 
Published: March 2010

Abstract
Effects of four benzoquinoline isomers on the filtration rate of the zebra mussel ( Dreissena polymorpha) were analyzed, to study the effect of minor differences in chemical structure on adverse biological effects. Filtration rates were measured after 48 h of exposure to different concentrations of acridine, phenanthridine, benzo[f]quinoline, and benzo[h]quinoline in the water. The 50% effective concentration (EC50) values for filtration rate of the four isomers differed significantly. Effects increased in the order benzo[f], -[h], -[b], and -[c]quinoline, and the difference between the most toxic isomer and the least toxic isomer amounted to a factor of 30. Attempts were made to relate these differences in toxicity to the structure of the isomers. Size- or topology-related molecular descriptors provided insufficient resolution to distinguish between the benzoquinoline isomers, and none of the electronic descriptors separately provided a significant correlation with the observed effects. In an alternative approach, molecular shape, accessibility, and minimum agent–macromolecule distance were used to represent repulsive and attractive forces between the benzoquinoline isomers and biological membranes. This approach could tentatively explain the observed effects and is supported by a high correlation between the EC50 data and the reversed-phase C18-HPLC behavior of the benzoquinolines (k0), which is likely to be governed by similar processes.
Inhibitors of the multixenobiotic resistance mechanism in natural waters: In vivo demonstration of their effects
Authors: Smital Tvrtko , Kurelec Branko 
Published: March 2010

Abstract
Xenobiotics in water that can inhibit the multixenobiotic resistance (MXR) defense mechanism in water organisms, the chemosensitizers, may cause severe ecotoxicological effects. We determined their concentrations in polluted and unpolluted river waters and seawaters using different methods. Here we present the method that enables direct determination of MXR-inhibitory potential in natural waters. This method measures the modulating potential of river water or seawater on the rate of rhodamine B (RB) accumulation in gills of a freshwater clam (Dreissena polymorpha) or a marine mussel (Mytilus galloprovincialis), respectively. The sensitivity of the method with RB even enabled the determination of MXR inhibitors by measuring their potential to modulate the rate of efflux of RB from gills of mussels. The concentrations of MXR inhibitors found by these methods (expressed in μM of verapamil-equivalents) were higher in natural waters from polluted rivers or in natural seawaters from polluted marine sites than in natural waters from unpolluted rivers or in natural seawaters from unpolluted sites. Polluted waters enhanced accumulation or decreased efflux rate of RB, a good substrate of P-glycoprotein, demonstrating that the complex mixture of chemicals present in polluted waters contains MXR-inhibiting potential. In addition, the efflux version of the method with RB has the clear advantage of not requiring that organisms be killed and so allows repeated use of the same individuals. In addition, it is the simplest and the most reliable method for measuring the activity of MXR in these organisms.
Use of perifusion to assess in vitro the functional integrity of interrenal tissue in teleost fish from polluted sites
Authors: Brodeur Julie C , Girard Caroline , Hontela Alice 
Published: March 2010

Abstract
A perifusion procedure adapted to field studies with fish was developed to assess in vitro the functional integrity of the cortisol-secreting interrenal tissue, which is distributed within the head kidney. The capacity of the interrenal tissue to respond to adrenocorticotropic hormone (ACTH) was assessed by stimulating isolated fish head kidney tissues with 10−7 M of ACTH139 during 10 min in perifusion, and monitoring the resulting increase in cortisol secretion. The interrenal tissue of yellow perch (Perca flavescens) from a site contaminated by a mixture of heavy metals and organic contaminants secreted significantly less cortisol in response to the standardized pulse of ACTH than did the interrenal tissue offish from a reference site (54.7 ± 8.9 vs 81.8 ± 17.7 ng cortisol/g head kidney, respectively). These results indicate that the disruption of the cortisol stress response observed in fish from polluted sites is caused, at least in part, by a dysfunction of the interrenal tissue. The perifusion procedure can be used to examine the effects of chronic exposures to pollutants on the functional integrity of the cortisol-secreting interrenal tissue in teleost fish.
A comparison of equilibrium partitioning and critical body residue approaches for predicting toxicity of sediment-associated fluoranthene to freshwater amphipods
Authors: Driscoll Susan Kane , Landrum Peter F 
Published: March 2010

AbstractEquilibrium partitioning (EqP) theory, which has been used to develop sediment quality criteria, predicts that the effects of organic compounds in sediments can be assessed by comparison of organic carbon-normalized sediment concentrations and estimated pore-water concentrations to effects determined in water-only exposures. A complementary approach, the critical body residue (CBR) theory, examines actual body burdens in relation to toxic effects. Critical body residue theory predicts that the narcotic effects of nonpolar compounds should be essentially constant for similar organisms, and narcosis should be observed at body burdens of 2 to 8 μmol/g tissue. This study compares these two approaches for predicting toxicity of the polycyclic aromatic hydrocarbon (PAH) fluoranthene. The freshwater amphipods Hyalella azteca and Diporeia spp. were exposed for up to 30 d to sediment spiked with radiolabeled fluoranthene at concentrations of 0.1 (trace) to 3,940 nmol/g dry weight (=346 μmol/g organic carbon). Mean survival of Diporeia was generally high (&gt;70%) and not significantly different from that of control animals. This result agrees with EqP predictions, because little mortality was observed for Diporeia in 10-d water-only exposures to fluoranthene in previous studies. After 10-d exposures, mortality of H. azteca was not significantly different from that of controls, even though measured interstitial water concentrations exceeded the previously determined 10-d water-only median lethal concentration (LC50). Equilibrium partitioning overpredicted fluoranthene sediment toxicity in this species. More mortality was observed for H. azteca at later time points, and a 16-d LC50 of 3,550 nmol/g dry weight sediment (291 μmol/g organic carbon) was determined. A body burden of 1.10 μmol fluoranthene-equivalents/g wet weight in H. azteca was associated with 50% mortality after 16-d exposures. Body burdens as high as 5.9 μmol/g wet weight resulted in little mortality in Diporeia. Diporeia, which has limited ability to metabolize fluoranthene and a higher lipid content, appears to be less sensitive than H. azteca, which does metabolize fluoranthene. These results demonstrate that the CBR approach is a useful complement to the EqP approach for the prediction and assessment of toxicity associated with contaminated sediments.
Chronic toxicity evaluation of wastewater treatment plant effluents with bioluminescent bacteria: A comparison with invertebrates and fish
Authors: Sweet Leonard I , Travers David F , Meier Peter G 
Published: March 2010

AbstractThe use of bioluminescent bacteria in chronic toxicity testing is a potentially useful yet unexplored tool in whole effluent biomonitoring. The purpose of this study was to determine the chronic toxicity of 14 different wastewater treatment plant effluents to Chronic Microtox® bacteria (Vibrio fischeri), a cladoceran (Ceriodaphnia dubia), and a minnow (Pimephales promelas). The invertebrate and fish have been utilized extensively for the evaluation of effluents and in establishing water quality criteria. The results of this study suggest that the 22-h Microtox Chronic Toxicity Test may correlate well with the most sensitive chronic no-observed-effect concentration value of the three-brood C. dubia test.
Bioconcentration of [14C]butyl benzyl phthalate in bluegill sunfish (Lepomis macrochirus)
Authors: Carr Katherine H , Coyle Gerald T , Kimerle Richard A 
Published: March 2010

Abstract
A short-term study was conducted to measure the bioconcentration factors for intact butyl benzyl phthalate (BBP) in whole fish, fillet (edible tissues), and viscera (non-edible) tissues of bluegill sunfish (Lepomis macrochirus). A group of 24 fish was exposed for 3.27 d to [14C] BBP in a dynamic system. Intact BBP was quantified by chromatographic analyses for each tissue fraction. Significant metabolism of BBP was observed in the fish, with intact BBP representing less than 3% of the total radioactivity in each type of tissue. Measured bioconcentration factors (BCFs) for intact BBP (normalized to 6% lipid) were 9.4 (whole fish), 8.7 (viscera), and 1.7 (fillet). These BCFs were considerably lower than previously published BCF values, which were based on total radioactive residues in whole fish.
A novel approach for dissolving chemicals with low aqueous solubility: Generator disk in the headspace
Authors: Ramos Eñaut Urrestarazu , Vaes Wouter H J , Verhaar Henk J M , Hermens Joop L M 
Published: March 2010

Abstract
In this communication a novel approach of preparing solutions of chemicals in water with a low solubility is presented. The method consists of loading a C18 coated Empore® disk with the chemical of interest, followed by desorption of the chemical into the water through the vapor phase.
Physiological profiling of indigenous aquatic microbial communities to determine toxic effects of metals
Authors: Lehman R Michael , Colwell Frederick S , Garland Jay L 
Published: March 2010

Abstract
Conventional bioassays for environmental assessment frequently rely on nonindigenous single species. We employed an assay in which whole environmental samples were distinguished by the ability of the native heterotrophic microbial communities to oxidize 95 different sole carbon sources generating a community-level physiological profile (CLPP). The average metabolic response (AMR) to the 95 variables defining the CLPP was used in laboratory bioassay studies with copper to construct dose–response curves over several different periods of exposure: 1 h (acute), 1 d, 2 d, and 4 d. The acute dose–response of Snake River bacterioplankton communities measured by AMR was compared to the dose–response of Photobacterium phosphoreum (used in the Microtox test) and a proprietary mixed consortia (used in the Polytox test). In laboratory bioassay studies, CLPP AMR exhibited acute dose–response behavior over a greater range in copper concentrations and with less variability (per dose) than Microtox and Polytox. The acute sensitivity of CLPP AMR to copper was roughly equal to Microtox and much greater than Polytox. After a longer exposure (1 d) to copper, Snake River communities became more sensitive to copper but no additional effect was observed when the exposure was increased to 2 and 4 d. Snake River communities pre-exposed to copper (1 mg/L) for 4 d prior to acute dose–response experiments showed no difference in AMR with respect to doses up to 10 mg/L, indicating the ability of the assay to detect adaptation. Several metal-contaminated streams in Idaho were used to field validate the CLPP approach for detecting impacts of metals in the environment. The response profiles of the bacterioplankton from two downstream sites receiving metal laden mine drainage were compared to those from reference sites upstream and further downstream of the location receiving the mine drainage. The AMR of the communities at the stream reference sites were greater than sites just below the mines. We ascribed this finding to acute physiological insult near the mines and subsequent recovery downstream. Multivariate analysis revealed differences in the pattern of carbon source utilization between chronically stressed (mine waters) and unstressed communities (reference stream sites). At the third site, treatment of mine drainage by an artificial wetland was assessed above and below the wetland; water exiting the treatment wetland had a higher AMR than water that was untreated. The CLPP approach has sufficient sensitivity to detect acute contaminant impact on physiological processes of the indigenous microbial community while providing data for evaluation of chronic stress-induced adaptations in microbial community structure.
Mechanistic quantitative structure–activity relationship model for the photoinduced toxicity of polycyclic aromatic hydrocarbons: I. Physical model based on chemical kinetics in a two-compartment system
Authors: Krylov Sergey N , Huang Xiao-Dong , Zeiler Lorelei F , Dixon D George , Greenberg Bruce M 
Published: March 2010

AbstractA quantitative structure–activity relationship model for the photoinduced toxicity of 16 polycyclic aromatic hydrocarbons (PAHs) to duckweed (Lemna gibba) in simulated solar radiation (SSR) was developed. Lemna gibba was chosen for this study because toxicity could be considered in two compartments: water column and leaf tissue. Modeling of photoinduced toxicity was described by photochemical reactions between PAHs and a hypothetical group of endogenous biomolecules (G) required for normal growth, with damage to G by PAHs and/or photomodified PAHs in SSR resulting in impaired growth. The reaction scheme includes photomodification of PAHs, uptake of PAHs into leaves, triplet-state formation of intact PAHs, photosensitization reactions that damage G, and reactions between photomodified PAHs and G. The assumptions used were: the PAH photomodification rate is slower than uptake of chemicals into leaves, the PAH concentration in aqueous solution is nearly constant during a toxicity test, the fluence rate of actinic radiation is lower within leaves than in the aqueous phase, and the toxicity of intact PAHs in the dark is negligible. A series of differential equations describing the reaction kinetics of intact and photomodified PAHs with G was derived. The resulting equation for PAH toxicity was a function of treatment period, initial PAH concentration, relative absorbance of SSR by each PAH, quantum yield for formation of triplet-state PAH, and rate of PAH photomodification. Data for growth in the presence of intact and photomodified PAHs were used to empirically solve for a photosensitization constant (PSC) and a photomodification constant (PMC) for each of the 16 PAHs tested. For 9 PAHs the PMC dominates and for 7 PAHs the PSC dominates.
Joint acute toxicity of diazinon and chlorpyrifos to Ceriodaphnia dubia
Authors: Bailey Howard C , Miller Jeffrey L , Miller Michael J , Wiborg Lan C , Deanovic Linda , Shed Theodore 
Published: March 2010

Abstract
Diazinon and chlorpyrifos are two organophosphorous pesticides widely found in municipal, agricultural, and urban storm water discharges. Because they are often found concurrently, their relationship with respect to joint toxicity is of interest, particularly in regard to interpreting the results of toxicity identification evaluations (TIEs) that point to metabolically activated organophosphorous pesticide(s) as causes of toxicity. Joint toxicity was evaluated using static tests that incorporated 48- to 96-h exposure periods using laboratory water, natural water, and urban storm water. Chemical concentrations were verified analytically. Mortalities were measured at 24-h intervals and joint toxicity was calculated on the basis of toxic units (TUs) for every time interval (1 TU = median lethal concentration [LC50]). Forty-eight-hour LC50 values ranged between 0.26 and 0.58 μg/L for diazinon and between 0.058 and 0.079 μg/L for chlorpyrifos. The 96-h values were approximately 65% of their respective 48-h values. Under the assumption of strict additivity, the LC50 (as TUs) of the mixture should be the sum of the respective fractions of diazinon and chlorpyrifos and should total unity. These values were calculated for a total of 12 time intervals. The TUs associated with the mixtures in laboratory water ranged between 0.89 and 1.46, with an average of 1.13. The values for the natural and storm water samples were similar to those obtained with laboratory water. These data confirmed the results of TIEs that suggested that diazinon and chlorpyrifos exhibit additive toxicity when present together.
Woodlouse locomotor behavior in the assessment of clean and contaminated field sites
Authors: Bayley Mark , Baatrup Erik , Bjerregaard Poul 
Published: March 2010

Abstract
Specimens of the woodlouse Oniscus asellus were collected at four clean field sites and from a recently closed iron foundry heavily contaminated with zinc, lead, chromium, and nickel. Each of the 30 woodlice per group was housed individually and acclimatized to laboratory conditions for 2 d on a humid plaster of paris substrate. Thereafter, the locomotor behavior of each animal was measured for 4 h employing automated computer-aided video tracking. Linear discriminant analysis of five locomotor parameters revealed average velocity and path length as the principle components separating the polluted site and control animals. Post hoc analysis of the discriminant variable for animals from all five sites showed that the animals from the polluted site where significantly hyperactive when compared to all controls. Further, control animals collected from sites separated by several hundred kilometers were remarkably similar in their locomotor behavior. This preliminary study highlights the potential utility of quantitative analysis of animal locomotor behavior in environmental monitoring.