bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographic trend in mercury measured in common loon feathers and blood
Authors: Evers David C , Kaplan Joseph D , Meyer Michael W , Reaman Peter S , Braselton W Emmett , Major Andrew , Burgess Neil , Scheuhammer Anton M 
Published: March 2010

Abstract
The common loon (Gavia immer) is a high-trophic-level, long-lived, obligate piscivore at risk from elevated levels of Hg through biomagnification and bioaccumulation. From 1991 to 1996 feather (n = 455) and blood (n = 381) samples from adult loons were collected between June and September in five regions of North America: Alaska, northwestern United States, Upper Great Lakes, New England, and the Canadian Maritimes. Concentrations of Hg in adults ranged from 2.8 to 36.7 μg/g (fresh weight) in feathers and from 0.12 to 7.80 μg/g (wet weight) in whole blood. Blood Hg concentrations in 3 to 6-week-old juveniles ranged from 0.03 to 0.78 μg/g (wet weight) (n = 183). To better interpret exposure data, relationships between blood and feather Hg concentrations were examined among age and sex classes. Blood and feather Hg concentrations from the same individuals were significantly correlated and varied geographically (r2 ranged from 0.03 to 0.48). Blood and feather Hg correlated strongest in areas with the highest blood Hg levels, indicating a possible carryover of breeding season Hg that is depurated during winter remigial molt. Mean blood and feather Hg concentrations in males were significantly higher than concentrations in females for each region. The mean blood Hg concentration in adults was 10 times higher than that in juveniles, and feather Hg concentrations significantly increased over 1 to 4-year periods in recaptured individuals. Geographic stratification indicates a significant increasing regional trend in adult and juvenile blood Hg concentrations from west to east. This gradient resembles U.S. Environmental Protection Agency-modeled predictions of total anthropogenic Hg deposition across the United States. This gradient is clearest across regions. Within-region blood Hg concentrations in adults and juveniles across nine sites of one region, the Upper Great Lakes, were less influenced by variations in geographic Hg deposition than by hydrology and lake chemistry. Loons breeding on low-pH lakes in the Upper Great Lakes and in all lake types of northeastern North America are most at risk from Hg.
Mercury and selenium accumulation in common loons (Gavia immer) and common mergansers (Mergus merganser) from Eastern Canada
Authors: Scheuhammer Anton M , Wong Allan H K , Bond Della 
Published: March 2010

Abstract
Liver, kidney, and breast muscle tissue from common loons (Gavia immer) and common mergansers (Mergus merganser) from eastern Canada were analyzed for total Hg, organic Hg, and Se concentrations. In both species, Hg and Se concentrations were generally highest in liver, followed by kidney, then breast muscle. As total Hg concentrations increased in liver and kidney tissues, the fraction that was methylmercury (MeHg) decreased. Livers and kidneys with the highest total Hg concentrations (&gt; 100 μg/g dry weight) had only 5 to 7% of the total as MeHg. Concentrations of MeHg were &lt;10 μg\g (dry weight) regardless of the total Hg concentration in liver and kidney. In contrast, the proportion of MeHg in breast muscle remained high (80–100%) in both loons and mergansers regardless of total Hg concentration, which ranged from 0.7 to 35 μg\ (dry weight7rpar;. Strong positive correlations were observed between total Hg and Se concentrations, but not between MeHg and Se, in kidney and liver tissues for both loons and mergansers. Mercury concentrations were significantly higher (analysis of variance, p &lt; 0.0001) in all three tissues of loons found in an emaciated condition compared with apparently healthy loons. Non-emaciated loons had Hg concentrations comparable to those of healthy mergansers, and concentrations were lower than those associated with Hg toxicity in birds. The elevated Hg concentrations in emaciated loons may have contributed to their impaired conditions; alternatively, the wasting of their muscle and other tissues may have caused apparent tissue Hg concentrations to increase. In any case, total Hg concentrations in liver and/or kidney tissue are insufficient criteria for making toxicologically relevant judgments of possible Hg toxicity. Because of the varying degrees of apparent Hg demethylation in liver, kidney, and other tissues and the association of the resulting inorganic Hg with Se in an apparently stable, toxicologically inert complex, estimates of organic Hg and Se concentrations, in addition to total Hg, in these organs are recommended.
A biological and chemical characterization strategy for small and medium-sized industries connected to municipal sewage treatment plants
Authors: Tarkpea Maria , Andrén Cecilia , Eklund Britta , Gravenfors Erik , Kukulska Zofia 
Published: March 2010

Abstract
A cost-effectives strategy for the characterization of wastewater from small and medium-sized industries is described. A mobile laboratory, equipped for performing on-site biological tests, was established near wastewater treatment facilities in two cities in Sweden for 1 week each in November 1992 and November 1993. The biological and chemical characterization was done on 24-h samples from 29 industries representing 12 types of activity with a bias toward the surface treatment and graphics industries. The biological testing program included a modified nitrification test, the Microtox® test, and a modified growth inhibition test using Selenastrum capricornutum (an alga test). A Ceriodaphnia dubia (crustacean) test was also used for some industries. Different chemical assessments, aimed at indicating toxic, persistent, and bioaccumulating substances, were chosen for each industry on the basis of information they provided. Results show that sampling period and time are important factors to consider when designing a characterization strategy. Twenty-four-hour sampling is preferred to weekly sampling because highly toxic emissions of short duration that are detrimental to the biological treatment plant may occur. Variability in emissions was shown in this study but would not have been detected by a study based on weekly sampling. The strategy developed in this study was shown to be both a cost-effective and efficient tool for characterizing effluents from small and medium-sized industries.
Physicochemical properties of polycyclic aromatic hydrocarbons: Aqueous solubilities,n-octanol/water partition coefficients, and Henry's law constants
Authors: de Maagd P Gert-Jan , ten Hulscher Dorien Th E M , van den Heuvel Henny , Opperhuizen Antoon , Sijm Dick T.H.M 
Published: March 2010

AbstractAqueous solubilities, n-octanol/water partition coefficients (Kows), and Henry's law constants were determined for a range of polycyclic aromatic hydrocarbons (PAHs) using a generator-column, slow-stirring, and gas-purge method, respectively. The currently obtained data were compared to available literature data. For seven of the PAHs no Kows previously were determined with the slow-stirring method. For four of the PAHs the present study reports the first experimental Henry's law constants. Relationships between subcooled liquid solubilities, Kows, and Henry's law constants as a function of molar volume are discussed. A consistent data set was obtained, for which an excellent correlation was found between subcooled liquid solubility and molar volume. A linear fit did not accurately describe the relationship between log Kow and molar volume. This is probably due to a decreasing solubility in n-octanol with increasing molar volume. Finally, a high correlation was found between Henry's law constant and molar volume. The presently obtained dataset can be used to predict the fate and behavior of unsubstituted homocyclic PAHs.
Metabolism of [14C]acrolein (Magnacide H® herbicide): Nature and magnitude of residues in freshwater fish and shellfish
Authors: Nordone Adrian J , Dotson Timothy A , Kovacs Martin F , Doane Rebecca , Biever Ron C 
Published: March 2010

AbstractArolein, anaquaticherbicide, is appliedas MAGNAIDE H® herbicide directly into the water of irrigation canals at concentrations of 1 to 15 ppm. Two representative freshwater fish species, the bluegill sunfish (Lepomis macrochirus) and the channel catfish (Ictalurus punctatus), and two representative freshwater shellfish species, a unionacean clam (Elliptio complanata) and the northern crayfish (Orconectes virilis), were exposed separately to two applications of [14C]acrolein, with 7 d between the two dosings. The nominal water concentrations were 0.02 and 0.1 ppm acrolein for fish and shellfish, respectively. Exposures were terminated 1 d after the second application. Metabolites were identified from the edible tissues of each test species; there was very little similarity in the metabolism of acrolein between them. The most notable observation was that acrolein was never detected in any of the tissues sampled. Glycidol, glycerol, 1,3-propanediol, and glyceric acid were the major metabolites found in the catfish, crayfish, bluegill, and clams, respectively. This study demonstrated that these test species, when exposed under static conditions to [14C]acrolein, are able to metabolize the parent compound and its residues in their edible tissues. The metabolism of [14C]acrolein is so rapid in the edible tissues of these species that neither acrolein nor its major oxidative and reductive metabolites, acrylic acid and allyl alcohol, respectively, were detected.
Genotoxic substances in the St. Lawrence system II: Extracts of fish and macroinvertebrates from the St. Lawrence and Saguenay rivers, Canada
Authors: White Paul A , Rasmussen Joseph B , Blaise Christian 
Published: March 2010

Abstract
Aquatic biota frequently accumulate organic contaminants and maintain steady state tissue concentrations that are as much as 105 times higher than those in the surrounding water. Although many researchers have studied the accumulation of genotoxic polycyclic aromatic hydrocarbons (PAHs) by aquatic biota, few researchers have used bioassays to investigate the accumulation of genotoxins. In several previous studies we used the SOS Chromotest to investigate the genotoxicity of industrial effluent extracts, sediment extracts, and bivalve tissue extracts. In this study we use the SOS Chromotest to investigate the accumulation of organic genotoxins by macroinvertebrates and fish in the St. Lawrence and Saguenay rivers (Quebec, Canada). Tissue concentrations of genotoxins (expressed as μg benzo[a]pyrene genotoxic equivalents) reveal bioconcentration factors in the 102 to 103 range. Concentrations are partially determined by lipid content (r2 = 0.22). Lipid-normalized values indicate that genotoxin concentrations in invertebrate tissues are significantly higher than those in fish. Fish values indicate that tissue concentrations are biodiminished, with fish at higher trophic levels having lower tissue burdens of genotoxins. The biodiminution pattern observed corresponds exceptionally well with trophic position assignments made by other authors. More contaminated sites yielded less contaminated specimens. This may be due to the induction of phase I and phase II detoxification enzymes that is likely to occur at high levels of exposure. Although the results do not support PAHs as the putative genotoxins, the results do indicate that the accumulated genotoxins have similar properties. Tissue to sediment ratios of genotoxins are similar to those observed for genotoxic PAHs, and far lower than those of more persistent organochlorines. Although we did not investigate genotoxic effects, we might expect the most dramatic effects in fish that consume contaminated macroinvertebrates.
In vitro hepatic metabolism of CYP3A-mediated drugs quinine and midazolam in the common brush-tailed possum (Trichosurus vulpecula)
Authors: Ho Ping-Chuen , Luo Xiao-Xing , Macauley Jackie S , Grigor Murray R , Wanwimolruk Sompon 
Published: March 2010

AbstractThis report characterizes the P450 isoenzymes involved in quinine metabolism in liver microsomes of the common brush-tailed possum (Trichosurus vulpecula). The mean maximal velocity (Vmax) for 3-hydroxyquinine formation in possum livers was 1,512 ± 510 pmol/mg protein/min (males) and 1,680 ± 690 pmol/mg protein/min (females). The mean Vmax value for 3-hydroxyquinine formation in possums was approximately threefold higher than that found in human livers. The mean apparent Michaelis constant (Km) for 3-hydroxyquinine formation in possum livers was 31.9 ± 16 μM in males and 16.1 ± 5 μM in females. At low concentrations of quinine (40 μM), the quinine 3-hydroxylation was inhibited more than 90% by midazolam, 60% by troleandomycin, 40% by erythromycin, and 47% by nifedipine, all of which are CYP3A inhibitors. Other inhibitors for CYP2C9/10, CYP2D6, CYP2E1, and CYP1A1/2 showed little or no inhibition effect on 3-hydroxylation of quinine. Xenobiotic inhibition studies suggest that the liver CYP3A enzyme family or one similar to human liver CYP3A is responsible for 3-hydroxylation of quinine in possum livers. The metabolism of midazolam to 1′-hydroxy and 4-hydroxy metabolites was also studied. The in vitro metabolism of midazolam was found to be much lower in possum liver microsomes as compared to that observed in human liver microsomes. The mean Vmax values for 4-hydroxy- and 1′-hydroxymidazolam in male possums were 179 ± 53 and 479 ± 333 pmol/mg protein/min, respectively. For female possums, the mean Vmax values were 235 ± 31 and 671 ± 143 pmol/mg protein/min, respectively. These Vmax values for male possums were 23 and 8 times less (17 and 6 times less for female possums), respectively, than those observed with human liver microsomes. The present study has demonstrated that, although possums are able to metabolize both midazolam and quinine, the capacity to metabolize midazolam is considerably lower in possum livers than in human livers. This finding could be useful for the selection of alternative poisons to control populations of possums.
Metabolism of trichloroethylene and chloral hydrate by the Japanese medaka (Oryzias latipes) in vitro
Authors: Lipscomb John C , Confer Patricia D , Miller Michael R , Stamm Steven C , Snawder John E , Bandiera Stelvio M 
Published: March 2010

AbstractTrichloroethylene (TRI), a common groundwater contaminant, is readily metabolized by mammals to produce chloral hydrate (CH), trichloroacetic acid (TCA), and trichloroethanol (TCOH). Cytochrome P450 (CYP) and other enzymes are responsible for formation of these metabolites, which are implicated in TRI's toxicity and carcinogenicity. To establish the validity of the Japanese medaka (Oryzias latipes) as an alternate test species for TRI, we examined the metabolism of TRI and CH, as well as CYP expression, in medaka liver preparations. Trichloroethylene was incubated with medaka microsomal protein, and metabolites were extracted and analyzed using gas chromatography. Microsome-mediated metabolism of TRI was observed, and a Km value for TRI oxidation of 540 μM and a Vmax value of 213 pmol/min·mg−1 protein were obtained. Conversion of TRI to CH, TCA, and TCOH was found with medaka hepatic subcellular fractions. In addition, a sex difference in hepatic microsomal TRI metabolism, specific CYP content, and ethoxyresorufin O-deethylase activity was noted. The lower specific activity of preparations from the livers of female medaka is compensated for by increased total protein in the larger liver mass of the female. Immunochemical analysis showed that CYP1A was readily detectable in medaka liver, but CYP2E1 was present at very low levels. These data suggest that TRI metabolism in medaka liver preparations mimics that observed in mammalian systems and supports their use as an alternative test species in the evaluation of the toxicity of TRI.
Relationship of atmospheric deposition to the water chemistry and biota of treehole habitats
Authors: Paradise Christopher J , Dunson William A 
Published: March 2010

Abstract
We monitored water chemistry of rain, stemflow, and treehole invertebrate communities in three landscape-scale regions in Pennsylvania receiving high, but different, atmospheric inputs of hydrogen and sulfate ions. We predicted that treeholes in the westernmost plateau region receiving the highest levels of those ions would have different water chemistry than those in other regions. We found that the plateau region had significantly lower pH and higher [SO4] than the central valley and easternmost ridge regions. This was correlated with higher [SO4] in plateau rain. Higher [SO4] in stemflow than rain indicated substantial dry deposition, and correlation of stemflow [SO4] and treehole [SO4] indicated that dry deposition influenced water chemistry of treeholes. Treehole [NO3] differed with time and region and was highest in August. Other chemical parameters in rain and stemflow were correlated with treehole water chemistry. Treehole [Mg] followed the pattern in stemflow, which was also correlated with rain [Mg]. However, higher [Mg], [Ca], and [K] in treehole water than in aqueous inputs indicated contribution of these cations via alternate pathways, such as the breakdown of leaf litter. No regional effects of deposition on treehole fauna were found, however, treehole insect densities and species richness were related to water volume, [SO4], [Na], and dissolved organic carbon (DOC).
Comparison of two models for predicting bioaccumulation of hydrophobic organic chemicals in a great lakes food web
Authors: Burkhard Lawrence P 
Published: March 2010

Abstract
The steady-state models of Gobas and Thomann for predicting chemical residues in aquatic food webs were compared. Bioaccumulation factors (BAFs) predicted on the basis of freely dissolved chemical in the water were not significantly different for piscivorous fish, based upon the 10th and 90th percentile predictions, except for chemicals with log n-octanol/water partition coefficients (Kows) ranging from 6.5 to 6.9, the region of maximum differences for chemicals with log Kows less than 8. For chemicals with log Kows greater than 8, the BAFs predicted by the models diverged. The BAFs predicted using the Gobas model were in slightly better agreement with measured BAFs (determined from Lake Ontario data) than those predicted using the Thomann model. Sensitivities of the input parameters used by both models were very similar. The most sensitive input parameters were lipid contents, Kow, and sediment–water column chemical concentration quotient (Πsocw) for both models, and the feeding preferences for benthic invertebrates (Diporeia) for the Thomann model. Simulations performed using uncertainties for the input parameters demonstrated that the Kow and Πsocw were the dominant sources of uncertainties for predicted BAFs by both models for the Great Lakes food web. For piscivorous fish, overall uncertainties in the predicted BAFs ranged from a factor of 3.3 to 5.5 (Gobas model) and from a factor of 3.3 to 8.7 (Thomann model) for chemicals with log Kows less than 7.6 (based upon the 10th and 90th percentile predictions).
Identification of the lampricide 3-trifluoromethyl-4-nitrophenol as an agonist for the rainbow trout estrogen receptor
Authors: Hewitt L Mark , Tremblay Louis , Kraak Glen J Van Der , Solomon Keith R , Servos Mark R 
Published: March 2010

Abstract
Lampricide formulations containing 3 -trifluoromethyl-4-nitrophenol (TFM) have been associated with induction of hepatic mixed function oxygenase (MFO) activity and altered levels of circulating steroids in fish. Bioassay-directed chemical fractionations have shown MFO induction to be associated with impurities in TFM field formulations. A similar toxicity identification/evaluation approach coupled to competitive binding to rainbow trout estrogen receptors (ER) was used to identify compounds associated with estrogenic responses in fish. In contrast to MFO induction, nearly all binding to the ER was associated with fractions containing TFM, TFM isomers, and p-chlorophenol.p-Chlorophenol did not show any affinity for the receptor when tested separately. Diphenyl ether impurities identified in the fractions causing MFO induction as well as analogues to dibenzo-p-dioxins suspected in these fractions also showed no affinity for the receptor when tested individually. Relative to estradiol, TFM demonstrated an affinity of 5.03 × 10−5, compared to 2.47 × 10−4 for p-nonylphenol, a reported estradiol agonist. Vitellogenin induction in primary cultures of rainbow trout hepatocytes indicated that TFM acts as an estradiol agonist.
Digestive proteases of the lugworm (Arenicola marina) inhibited by Cu from contaminated sediments
Authors: Chen Zhen , Mayer Lawrence M 
Published: March 2010

Abstract
We examined potential toxic effects of copper released from contaminated sediments during deposit feeding of the lugworm, Arenicola marina. Titration of Cu solution into gut fluids can result in decreases in protease activity if sufficient Cu is added. The effects of Cu on gut proteases were confirmed by incubation of gut fluids with Cu-contaminated harbor sediments. Monitoring of Cu titration into gut fluids shows that enzyme inhibition and quenching of gut protein fluorescence occur only when sufficient Cu has been added to allow inorganic Cu species to become abundant. This threshold level probably represents the exhaustion of strong binding sites that act as protection against enzyme inhibition. Thus, sediments contaminated with Cu may have inhibitory effects on digestive processes in lugworms.
Spatial and temporal variation in results of purple urchin (Strongylocentrotus purpuratus) toxicity tests with zinc
Authors: Phillips Bryn M , Anderson Brian S , Hunt John W 
Published: March 2010

Abstract
Purple urchins (Strongylocentrotus purpuratus) were maintained in year-round spawning condition in the laboratory for use in fertilization and larval development experiments designed to assess temporal variability in response to zinc. Results of these tests were compared to those from tests using gametes obtained from a field-collected population. Fertilization and larval development tests were also conducted comparing field-collected purple urchins from three geographically distinct groups on the West Coast of the United States. Fertilization tests conducted to assess temporal variability produced variable median effects concentrations (EC50s) ranging from 4.1 to &gt;100 μg/L zinc. Larval development tests produced more consistent EC50s, which averaged 107.4 ± 21.9 μg/L zinc for laboratory purple urchins and 97.2 ± 19.2 μg/L zinc for field-collected purple urchins. Larval development tests did not demonstrate significant differences in response to zinc between geographically distinct purple urchin populations. Fertilization test variability was examined in terms of sperm concentration and sperm collection method during two seasons. Reduced variability was found with dry sperm collection in tests conducted in March 1995 but increased again in tests conducted in June 1995, regardless of sperm collection method. Increased variability in response to zinc may be caused by seasonal temperature effects.