bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical detection of lead in plant tissues
Authors: Tung Gabrielle , Temple Patrick J. 
Published: March 2010

Abstract
A histochemical staining technique using sodium rhodizonate was developed for detecting lead in living or preserved plant tissues. Sodium rhodizonate formed a bright scarlet-red precipitate with lead at pH 3.0, but showed no significant color responses with other metals. The precipitation of lead by this staining technique was confirmed by detection of lead in the red-stained precipitate with electron microscopy X-ray analysis. This histochemical technique for lead provided rapid, quantifiable, and unambiguous evidence for the accumulation and localization of lead in plant tissues. Soil-borne lead accumulated primarily in the roots, although at high concentrations, lead also accumulated at the ends of transpirational streams, particularly at hydathodes, trichomes, and the termini of xylem streams. Lead deposited from the atmosphere accumulated on the surface of conifer foliage and also appeared in or on cell walls of various internal cells and tissues. Lead concentrations in foliage and the color intensity of the stained deposits in spruce foliage decreased with distance from the lead source and increased with age of needles. No evidence of lead deposition inside cell contents was observed by this stain.
Effects of metal contamination from mine tailings on allozyme distributions of populations of great plains fishes
Authors: Roark Shaun , Brown Karen 
Published: March 2010

Abstract
This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining District in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. Although total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness, and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (Gpi) in F. notatus and P. notatus, malate dehydrogenase (Mdh) in G. affinis, and phosphogluconate dehydrogenase (Pgdh) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for Gpi and Pgdh loci, but not for products of the Mdh locus. No sensitivity to lead was noted for allozymes. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results provide additional support for the use of genetic structure and variability as a bioindicator of heavy metal contamination.
Fate and effects of the herbicide atrazine in flow-through wetland mesocosms
Authors: Detenbeck Naomi E. , Hermanutz Roger , Allen Kathleen , Swift Michael C. 
Published: March 2010

Abstract
Wetland mesocosms were exposed to increasing concentrations of atrazine over time at levels typical of midwestern surface waters following spring runoff (15 to 75 μg/L). Atrazine had a half-life of 8 to 14 d in the 230-m-long wetlands. End points measured included nutrient levels; periphyton biomass; periphyton productivity and respiration; growth of selected macrophytes; and survival and growth of Daphnia magna (15, 25 μg/L atrazine), Rana pipiens (15, 25 μg/L), and Pimephales promelas larvae (25 to 75 μg/L) and adults (50, 75 μg/L). Interaction between nutrient status or grazing intensity and atrazine effects were measured using periphyton enrichment and grazing exclosure experiments. Only periphyton, Ceratophyllum demersum, Zizania aquatica, and Daphnia were significantly affected by atrazine at any of the concentrations tested. Periphyton net productivity was significantly depressed by incubation in treated water as compared to control water at ≥25 μg/L atrazine (9 to 27-d exposures). In response, dissolved nutrient concentrations increased in treated mesocosms after 14 d. Ceratophyllum length/weight ratios increased after 6-d exposures to 50 μg/L atrazine, while Zizania senesced prematurely during treatments of 50 or 75 μg/L atrazine (97 d of cumulative exposure). Periphyton developed resistance to atrazine only at concentrations ≥50 μg/L. Atrazine effects on periphyton composition varied with the N:P supply ratio. Daphnia survival was significantly depressed at 15 μg/L atrazine (48-h exposures).
Multivariate modeling of pcb bioaccumulation in three-spined stickleback (Gasterosteus aculeatus)
Authors: VanBavel Bert , Andersson Patrik , Wingfors Hakan , Rappe Christoffer , Tysklind Mats , Bergqvist Per-Anders , Ahgren Jorgen , Norrgren Leif 
Published: March 2010

Abstract
Three-spined sticklebacks were exposed to 20 polychlorinated biphenyls (PCBs) through gastrointestinal intake. The PCBs, viz. 2,2′,3,4- TeCB, 2,2′,4,6′-TeCB, 2,3,3′,5′-TeCB, 2,3,4,4′-TeCB, 2,3′,4,5′- TeCB, 3,3′,4,5-TeCB, 2,2′,3,4′,6-PeCB, 2,2′,4,4′,5-PeCB, 2,2′,4,6,6′-PeCB, 2,3,3′,5,6-PeCB, 2,3,4,4′,6-PeCB, 3,3′4,4′,5- PeCB, 2,2′,3,4,5,6′-HxCB, 2,2′,4,4′,5,5′-HxCB, 3,3′,4,4′,5,5′-HxCB, 2,2′,3,3′,4,5,6-HpCB, 2,2′,3,4,4′,6,6′-HpCB, 2,2′,3,4′,5,6,6′-HpCB, 2,3,3′,4,4′,5,6-HpCB, and 2,3,3′,4′,5,5′,6-HpCB, were selected by means of a full factorial design in combination with principal component analyses based on several physicochemical properties of tetra- through hepta-PCBs. After exposure to the training set, pooled samples of the sticklebacks were analyzed by GC-MS after lipid determination and cleanup using Florisil open-column chromatography. Bioaccumulation factors (BAFs) were calculated on a lipid basis by dividing the PCB concentrations in the fish by the respective concentrations in the feed. Higher chlorinated PCBs showed, in general, higher bioaccumulation than the lower chlorinated congeners. Polychlorinated biphenyls with vicinal hydrogens in the meta- and para-positions exhibited low bioaccumulation. Finally 18 of the 20 measured BAFs were used to calculate a multivariate quantitative structure–activity relationship (QSAR) by means of partial least squares fitting to latent structures. By applying this QSAR, the bioaccumulation potentials of 136 nontested tetra- through hepta-PCB congeners were predicted.
Mixed-function oxidase enzyme activity and oxidative stress in lake trout (Salvelinus namaycush) exposed to 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126)
Authors: Palace Vince P. , Klaverkamp Jack F. , Lockhart W. Lyle , Klaverkamp Jack F. , Lockhart W. Lyle , Metner Don A. , Muir Derek C. G. , Brown Scott B. 
Published: March 2010

Abstract
Juvenile lake trout were intraperitoneally injected with corn oil containing nominal concentrations of 0, 0.6, 6.3, or 25 μg [14C]-3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) per gram of body weight. The PCB-126 accumulated in liver in a dose-dependent manner to a sustained concentration by 6 weeks and remained elevated for the 30-week experimental period. Mixed-function oxidase (MFO) enzyme activity was elevated in the two highest dose groups relative to the control group, but not in the low-dose group throughout the 30 weeks. Oxidative stress, measured by the thiobarbituric acid reactive substances test, was correlated with ethoxyresorufin O-deethylase and was elevated in liver of the two highest PCB dose groups but not the low-dose group. The activities of the enzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB-126 exposure. The nonenzymatic antioxidant tocopherol was depleted to approximately 75% of the control concentration in liver of all three PCB-dosed groups. Hepatic ascorbic acid levels were not different in any of the treatment groups. Retinol was depleted by greater than an order of magnitude in liver of the two highest dose groups but not in the low-dose group. This study demonstrates a correlation between hepatic MFO activity and oxidative stress in PCB-exposed lake trout. Tocopherol and retinol may be important mediators of oxidative stress but additional study is required to confirm the antioxidant activity of retinol.
Use of rodeo® and X-77® spreader to control smooth cordgrass (Spartina alterniflora) in a southwestern washington estuary: 2. Effects on benthic microflora and invertebrates
Authors: Simenstad Charles A. , Cordell Jeffery R. , Tear Lucinda , Weitkamp Laurie A. , Paveglio Fred L. , Kilbride Kevin M. , Fresh Kurt L. , Grue Christian E. 
Published: March 2010

Abstract
In August 1992, we conducted an intensive short-term (within 119d)experiment in southern Willapa Bay, Washington, to evaluate the potential effects on mudflat benthic communities of herbicide control of smooth cordgrass, Spartina alterniflora Loisel. A mixture of glyphosate (Rodeo®; 4.7 L ha−1) and an associated surfactant, alkylarylpolyoxyethylene (AAPOE, X-77® Spreader; 1 L ha−1) was applied aerially to three mudflat sites with invasive S. alterniflora. Sediment structure (grain size), edaphic microalgal biomass (chlorophyll a), and densities of benthic and epibenthic meiofauna and benthic macrofauna were sampled systematically in treated and adjacent control (untreated) plots 1 d before, immediately after, and 1, 14, 28 and 119 d after spraying. These mudflat biota showed no definitive differences in population trends that would indicate acute responses to the herbicide and surfactant applications over the 119-d duration of the experiment. Two-way ANOVA tests of differences in slope of linear regressions of mean plot microalgal biomass and invertebrate density of 19 taxa groups or species testing short-term (2 weeks) and long-term (17 weeks) trends in response to the experimental treatment tests indicated no significant (p &lt; 0.1) treatment and only three site effects. Natural variability in the standing stocks (in the case of benthic microalgae) or densities (invertebrates) of most of the 19 indicator taxa prior to spray application was sufficiently high within and between treatment and control plots and among sites to preclude strong inferential tests of acute effects. Although differences in mudflat habitats (e.g., tidal elevation, sediment structure) inherent in the sites prior to treatment affect the power of our ability to test direct effects, there were no indications of either short- or long-term effects on the mudflat community of aerially applying this concentration of herbicide and surfactant. This study did not explicitly address either sublethal or indirect ecological effects, such as associated with an observed decrease in the exotic eelgrass Zostera japonica, which might appear as a longer-term, more subtle response by the mudflat community.
Biogeochemical interactions affecting hepatic trace element levels in aquatic birds
Authors: Möller Gregory 
Published: March 2010

Abstract
Knowledge of elemental interactions is important to the toxicological assessment of wildlife in the geochemical environment. This study determines the concentrations of Al, As, B, Ba, Be, Cd, Cr, Cu, Fe, Pb, Li, Mg, Mn, Hg, Mo, Ni, Se, Ag, V, and Zn in aquatic bird liver, fish liver, whole bivalves, insects, and waters in several aquatic ecosystems in northern California. There is evidence of strong in vivo and environmental interactions, including the observation of manganese as a possible cofactor or indicator in selenium bioaccumulation. The nearest neighbor selenium correlation in aquatic bird liver tissue that results from this work is Cd–Mn–Se–Hg–As. The correlation of liver selenium to manganese in vivo and the result that the majority of the variance in liver selenium concentration is contained in the manganese term of the regression model relating Se to Cd, Mn, and Hg is new knowledge in the study of aquatic birds. A linear relationship between liver selenium and environmental manganese (water and sediment) is found in the data, suggesting a water chemistry compartmentalization or activation of toxicants. Alternatively, the hepatic concentrations of selenium, manganese, and iron suggest induction of enzymes in response to oxidative stress.
Effect of cadmium on reductive dechlorination of trichloroaniline
Authors: Pardue John H. , Kongara Selvi , Jones Jack W. 
Published: March 2010

Abstract
The effect of a transition metal, cadmium (Cd), on reductive dechlorination of a model chlorinated organic, 2,3,4-trichloroaniline (2,3,4-TCA), was determined in the laboratory in three anaerobic, flooded soils with varying properties. Dechlorination of 2,3,4-TCA was inhibited over a continuum of pore-water-soluble Cd concentrations (10–200 μg/L) in mineral-dominated rice paddy and bottomland hardwood soils. In organic-dominated marsh soil, however, a critical inhibitory level of pore-water-soluble Cd (200 μg/L) was observed. Lower-chlorinated aniline metabolites differed with soluble Cd concentration. Different metabolites (2,3-dichloroaniline and 2-chloroaniline) were observed in some soils as Cd neared the completely inhibitory concentration. Speciation of soluble Cd was necessary to predict whether inhibition would occur, particularly in the presence of high concentrations of organic ligands such as humic acids. Selective extractions and measurement of acid-volatile sulfides provided additional information but did not adequately predict inhibition of dechlorination. These results demonstrate the importance of quantification and speciation of pore-water metal concentrations in predicting potential inhibition of anaerobic biodegradation reactions such as reductive dechlorination.
Predicting soil sorption coefficients of organic chemicals using a neural network model
Authors: Gao Chao , Govind Rakesh , Tabak Henry H. 
Published: March 2010

Abstract
The soil/sediment adsorption partition coefficient normalized to organic carbon (Koc) is extensively used to assess the fate of organic chemicals in hazardous waste sites. Several attempts have been made to estimate the value of Koc from chemical structure or its parameters. The primary purpose of this study was to develop a nonlinear model for estimating Koc applicable to polar and nonpolar organics based on artificial neural networks using the octanol/water partition coefficient (Kow) and water solubility (S). An analytic equation was obtained by starting with a neural network, converging the bias and weight values using the available data on water solubility, octanol/water partition coefficient, and the normalized soil/sediment adsorption partition coefficient, and then combining the equations for each node in the final neural network. For the 119 chemicals in the training set, estimates using the neural network equation lie outside the 2σ region (the standard deviation for the training set, σ = 0.52) for only five chemicals, while all the chemicals in the test set lie within the 2σ region. It was concluded that the neural network equation outperforms the linear models in fitting the Koc values for the training set and predicting them for the test set.
Studies on the effects of the herbicide simazine on microflora of four agricultural soils
Authors: Martinez-Toledo Maria Victoria , Salmeron Victoriano , Rodelas Belen , Pozo Clementina , Gonzalez-Lopez Jesus 
Published: March 2010

Abstract
The effects of 10, 50, 100, 200, and 300 μg simazine per gram of soil was studied under aerobic conditions. Compared with control soil, the herbicide simazine did not affect bacterial populations, fungi, aerobic dinitrogen-fixing bacteria, denitrifying bacteria, and nitrogenase activity. However, nitrifying bacteria were decreased at concentrations of 50 to 300 μg/g. The negative effects observed on nitrifying bacteria in soil amended with simazine were particularly evident after a second application of herbicide, showing that these microorganisms cannot tolerate certain concentrations of simazine.
Quantitation of dose-dependent increases in CYP1A1 messenger RNA levels in juvenile chinook salmon exposed to treated bleached-kraft mill effluent using two field sampling techniques
Authors: Campbell Pamela M. , Kruzynski George M. , Birtwell Ian K. , Devlin Robert H. 
Published: March 2010

Abstract
Increases in hepatic CYP1A1 messenger RNA (mRNA) levels were quantitated, using a reverse-transcriptase–competitive-polymerase-chain-reaction assay, from juvenile chinook salmon following exposure to treated bleached-kraft mill effluent (BKME). Two tissue preservation techniques, alcohol fixation and freezing, were compared and both found to be valid, although absolute values obtained differed between the methods. The results of this study show that juvenile chinook respond with a dose-dependent induction of CYP1A1 mRNA to levels of treated BKME found under winter, low-flow conditions downstream of pulp mills in the Fraser River, British Columbia, Canada. The validation of alcohol fixation as a sampling technique for studies on mRNA levels improves the ease of field sampling and increases the feasibility of using CYP1A1 mRNA level as a bioindicator of exposure of fish to specific chemical contaminants.
Effects of the insecticide dursban® 4E (active ingredient chlorpyrifos) in outdoor experimental ditches: I. Comparison of short-term toxicity between the laboratory and the field
Authors: van Wijngaarden René P. A. , van den Brink Paul J. , Crum Steven J. H. , Brock Theo C. M. , Leeuwangh Peter , Voshaar Oude Jan H. 
Published: March 2010

Abstract
Using the insecticide Dursban ® 4E (active ingredient chlorpyrifos) as the test compound, results of laboratory acute single-species toxicity tests with indigenous and standard test species were compared with short-term direct effects in outdoor experimental ditches (mesocosms). In the mesocosms a regression experiment was performed with nominal initial chlorpyrifos concentrations of 0.1, 0.9, 6, and 44 μg/L. The mesocosms were sprayed once. Effects were investigated by sampling macroinvertebrates and zooplankton and by doing in situ cage experiments with several species. Chlorpyrifos concentrations showed highest spatial and temporal variation within 2 d of treatment. Acute effects were observed on arthropods only and essentially were manifest on day 0. Short-term direct effects in the mesocosms could be quantified by a regression method for seven of 120 species. For these species, 48- and 96-h median effective concentrations (EC50s) ranged from 0.1 to 3.4 μg/L and were in the same order of magnitude as their laboratory EC50s. Susceptibility of the most sensitive standard test species (Daphnia magna; 48-h median lethal concentration [LC50], 1 μg/L) was more or less representative of susceptible indigenous species. In the mesocosms effects were negligible at the 0.1-μg/L treatment level. A safety factor of 0.1 (48-h LC50 of Daphnia magna) may have protected almost all of the species in the community in the mesocosms against short-term direct effects. A safety factor of 0.01 probably protected the most susceptible taxa we found (laboratory 96-h EC10 for Gammarus pulex, 0.02 μg/L; no-observed-effect concentration for Copepoda, &lt;0.1 μg/L). The question remains, however, of whether long-term (in)direct effects on the populations or the community may occur at the 0.1-μg/L treatment level.
Trends in 2,3,7,8-TCDD concentrations in fish tissues downstream of pulp mills bleaching with chlorine
Authors: Abbott Joan D. , Hinton Steven W. 
Published: March 2010

Abstract
Field measurements of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations in fish tissues from riverine environments impacted by treated pulp and paper industry effluent in the United States were analyzed. Data from 39 sites in 14 states across the four major U.S. paper-making regions were assembled and analyzed to determine the annual change in lipid-normalized concentrations of TCDD in fish tissue. The results provide strong evidence of a nationwide trend of decreasing lipid-normalized TCDD concentrations in fish tissue, with 84% of the examined sites showing a decrease. While the paucity of data currently limits any conclusions regarding the statistical significance at individual sites, the overall median rate calculated indicates a 0.36 annual fractional decrease in lipid-normalized concentrations of TCDD in fish tissue (0.18 to 0.51, 95% confidence interval); the average annual fractional decrease was 0.35 (0.23 to 0.47, 95% confidence interval). Subdividing fish into benthic and nonbenthic categories resulted in rates which were not significantly different from one another for both the median and mean statistics.
Enhanced antibody responses in mink (Mustela vison) exposed to dietary bleached-kraft pulp mill effluent
Authors: Smits Judit E. G. , Wobeser Gary A. , Haines Deborah M. , Blakley Barry R. 
Published: March 2010

Abstract
Mammalian top predators such as mink (Mustela vison) that inhabit a semi-aquatic environment may be exposed to bleached-kraft mill effluent (BKME), directly through the water, or indirectly through bioaccumulation of compounds in BKME via the food chain. To assess the potential immunotoxic effects of this exposure, the antibody response of 20 female mink exposed to dietary BKME for 26 weeks was studied. After 16 weeks on the BKME diet, sera were collected to determine prevaccination antibody levels against a mycobacterial antigen. Four weeks later, during early gestation, mink were immunized with a vaccine prepared from a culture of bacillus Calmette–Guérin (BCG). Sera were collected 6 weeks following vaccination and antimycobacterial antibody levels measured. A protein extract from cultured BCG was used as the capture antigen in an indirect enzyme-linked immunosorbent assay to quantify mink immunoglobulin specific for BCG. Both the control and BKME-exposed mink had significantly increased BCG antibody concentrations postimmunization compared to preimmunization levels. The BKME-exposed group antibody levels postimmunization were significantly higher (p = 0.029) than the corresponding control group. These results demonstrate immune modulation from dietary BKME, which was expressed as enhanced specific antibody production in mink. A related study describes cell-mediated immunosuppression in these BKME-exposed mink, supporting the hypothesis of immune deviation proposed here.