bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impacts of UV radiation and photomodification on the toxicity of pahs to the higher plant Lemna gibba (duckweed
Authors: Huang Xiao-Dong , Dixon D. George , Greenberg Bruce M. 
Published: March 2010

Abstract
The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activate the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene &gt; phenanthrene &gt; benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid (half-lives in hours), and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated.
Biomarkers of contaminant exposure in common terns and black-crowned night herons in the Great Lakes
Authors: Hoffman David J. , Smith Gregory J. , Rattner Barnett A. 
Published: March 2010

Abstract
Morphological and biochemical indexes of contaminant exposure were examined in hatching common terns (Sterna hirundo) and black-crowned night herons (Nycticorax nycticorax) from industrialized and nonindustrialized locations in the Great Lakes. In 1984, naturally incubated, pipping common tern and black-crowned night heron embryos collected from industrialized locations exhibited smaller femur-length-to-body-weight ratios, elevated hepatic microsomal aryl hydrocarbon hydroxylase (AHH) activities, and lower hepatic DNA concentrations (P &lt; 0.05). In addition, a high incidence of subcutaneous edema was noted in pipping herons (P &lt; 0.01). In 1985, reduced hatching success was observed for laboratory-incubated common tern eggs collected from the industrialized sites, compared to nonindustrialized sites (P &lt; 0.01). Day-old hatchlings exhibited reduced femur-length-to-body-weight ratio, developmental anomalies, and elevated hepatic AHH activity (P &lt; 0.05). For hatching common terns studied in 1984 and 1985, femur-length-to-body-weight ratio was inversely related to AHH activity (r = −0.67, P &lt; 0.05) and inversely related to log-transformed PCB concentrations (r = −0.70, P ≤ 0.05) of unincubated eggs from the same colony. The activity of AHH in hatching terns was also directly related (r = 0.71, P ≤ 0.05) to log-transformed PCB concentrations in unincubated eggs. Other examined contaminants, including DDE, other organochlorine pesticides, and mercury, were not directly related to these effects.
Metal accumulation and metallothionein concentrations in tree swallow nestlings near acidified lakes
Authors: Louis Vincent L. St. , Breebaart Loes , Barlow Jon C. , Klaverkamp Jack F. 
Published: March 2010

Abstract
We studied metal accumulation in hepatic and renal tissues of tree swallow (Tachycineta bicolor) nestlings at acidified and nonacid reference lakes in northwestern Ontario Hepatic concentrations of metallothionein (metal binding proteins, MT) in tree swallow nestlings were negatively correlated with pH of the nest-site lake. Combined concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Although no overt signs of metal toxicity were observed in nestlings near acid lakes, our results clearly provided evidence that metals are transferred from acid lakes to birds and that these metals are correlated with increases in hepatic MT production.
Inhibition of hepatic thyroxine 5′-monodeiodinase by humic acids
Authors: Huang Tien-Shang , Lu Fung Jou , Chopra Inder J. 
Published: March 2010

Abstract
Humic substances are implicated as a kind of environmental goitrogen, and increased prevalence of goiter has been recently noticed in the blackfoot disease endemic area in the southwest of Taiwan, where well water is rich in humic substances. In this study we have investigated the effects of humic substances on hepatic 5′-monodeiodinase (5′-MD) in rats to gain knowledge of such effects on thyroid hormone metabolism. Aliquots of rat liver microsome (about 5 μg of protein) were preincubated in 0.1 M Tris buffer (pH 7.4) for 30 min with or without various concentrations (12.5-800 μg/ml) of humic acids, then incubated with thyroxine (T4, 2.5 μM; final volume 1 ml) and dithiothreitol (DTT, 5 or 25 mM) in the same buffer for 30 min. The 3,5,3′-triiodothyronine (T3) generated during incubation was quantified by radioimmunoassay (RIA) of ethanol extracts of the incubation mixture. Humic acids caused a dose-dependent inhibition of hepatic T4 5′-monodeiodi-nation. The mean dose (± sd) that caused a 50% inhibition of 5′-MD activity was 58 ± 6 μg/ml (n = 8). The inhibition was not a result of the depletion of T4 during incubation of T4 with humic acids. Free radical scavengers — catalase (300 U/ml) and superoxide dismutase (100 U/ml) — had no effect on the inhibition of hepatic T4 5′-monodeiodination induced by humic acids. Our data suggest that humic acids influence thyroid hormone metabolism by inhibiting hepatic 5′-MD activity.
Molecular size exclusion by soil organic materials estimated from their swelling in organic solvents
Authors: Lyon William G. , Rhodes David E. 
Published: March 2010

Abstract
A published method previously developed to measure the swelling characteristics of powdered coal samples has been adapted for swelling measurements on various peat, pollen, chitin, and cellulose samples. The swelling of these macromolecular materials is the volumetric manifestation of absorption, that is, sorption by dissolution (or partitioning) of the sorbed liquids into cross linked macromolecular solid phases. Direct evidence for the existence of this additional category of sorbed materials has been obtained for soil organic materials by the present research, however, it seems to be limited by molecular size exclusion effects to fairly small molecules. Liquids with molar volumes greater than about 93 cm3 mol−1 appeared to be strongly excluded from sorption inside most cross linked soil organic materials studied in this work. Cellulose excluded liquids with molar volumes greater than about 88 cm3 mol−1
Biomonitoring environmental contamination with pipping black-crowned night heron embryos: Induction of cytochrome P450
Authors: Rattner Barnett A. , Melancon Mark J. , Custer Thomas W. , Hothem Roger L. , King Kirke A. , Lecaptain Leonard J. , Spann James W. , Woodin Bruce R. , Stegeman John J. 
Published: March 2010

AbstractCytochrome P450-associated monooxygenase activities and cytochrome P450 proteins were measured in pipping black-crowned night heron (Nycticorax nycticorax) embryos collected from a reference site (next to the Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). In a laboratory study, artificially incubated night heron embryos from the reference site were treated with 3-methylcholanthrene (200 μg administered into the air cell 2 d before pipping) or phenobarbital (2 mg daily for 2 d before pipping). Compared to controls (untreated + vehicle-treated embryos), 3-methylcholanthrene induced a greater than fivefold increase in activities of several monooxygenases (arylhydrocarbon hydroxylase, AHH; benzyloxyresorufin-O-dealkylase, BROD; ethoxyresorufin-O-dealkylase, EROD; pentoxyresorufin-O-dealkylase, PROD) and a greater than 100-fold increase in the concentration of immunodetected cytochrome P450 1A (CYP1A). Phenobarbital treatment resulted in only a slight increase in BROD activity but induced proteins recognized by antibodies to cytochrome P450 2B (CYP2B) by 2,000-fold. In a field study, activities of AHH, BROD, EROD, and ethoxycoumarin-O-dealkylase (ECOD) were up to 85-fold higher in pipping black-crowned night herons collected from Cat Island compared to other sites. Hepatic CYP1A and CYP2B cross-reactive proteins were detected in significantly more individuals from Cat Island than from the reference site. Greatest burdens of total PCBs and p,p′-DDE were detected in embryos from Cat Island. Cytochrome P450-associated monooxygenase activities and cytochrome P450 proteins (AHH, BROD, EROD, ECOD, CYP1A, CYP2B) were significantly associated with total PCB burdens (r = 0.50-0.72). These data indicate that cytochrome P450 may be a useful biomarker of exposure to some PCB mixtures in black-crowned night heron embryos.
Assessment of published literature pertaining to the uptake/accumulation, translocation, adhesion and biotransformation of organic chemicals by vascular plants
Authors: Nellessen James E. , Fletcher John S. 
Published: March 2010

Abstract
Information in the UTAB data base was used to determine the general makeup of published data pertaining to how vascular plants influence organic chemicals in the environment. UTAB contains information on the uptake/accumulation, translocation, adhesion, and biotransformation of xenobiotic organic chemicals by vascular plants. The percentage distribution of data (records) in UTAB among four important fate processes was 58, 16, 7, and 19 for uptake/accumulation, translocation, adhesion, and biotransformation, respectively. The tabulated data show the 30 most frequently reported chemicals, the 30 plants most often studied, and the frequency of examining plants maintained under different experimental conditions (contaminated site, controlled environments, etc.). Sixty-five percent of the 1,047 chemicals in the data base are pesticides, and data (records) pertaining to these compounds account for 90% of the information in the data base. Crop species account for 33% of the plants and 77% of the data in UTAB. These summary values illustrate the imbalance of attention given to agrichemicals vs. industrial and municipal waste compounds, and emphasize the need for additional research addressing the influence of plants on environmental pollutants, with special attention given to industrial pollutants and native plants.
Biogeochemical processes affecting selenium cycling in wetlands
Authors: Masscheleyn Patrick H. , Patrick William H. 
Published: March 2010

Abstract
Important selenium data in the literature are discussed with reference to the biogeochem-ical processes affecting selenium cycling in wetlands. Selenium oxidation-reduction reactions are shown to be the most important biogeochemical processes controlling speciation, precipitation/dissolution, sorption/desorption, methylation, and volatilization of selenium. Furthermore, bioavailability and toxicity of selenium, with reference to wetland ecosystems, are summarized. Based on the information available in the literature, a conceptual model depicting selenium chemistry and behavior in wetlands is described.
Mercury cycling and effects in freshwater wetland ecosystems
Authors: Zillioux E.J. , Porcella D.B. , Benoit J.M. 
Published: March 2010

Abstract
This literature review borrows from diverse fields because of the paucity of freshwater wetland studies on mercury cycling and effects. Peat cores provide an excellent means of dating mercury deposition temporal patterns. Conclusions about cycling suggest that a biogeochemical model would prove useful for evaluating wetland processes of mercury transformation and accumulation. Mercury methylation and the association of mercury with organic matter require additional research. Wetlands trap and release mercury, and its association with organic matter seems to affect the release rate. At high exposure, usually associated with laboratory studies or waste discharges, a variety of biotic toxic responses are observed. Predator species accumulate mercury predictably, and residue-effect relationships seem useful for an index of ecologic damage. More definitive conclusions require additional research to define the ecosystem properties that affect mercury transfer to wetland predators.
Fate of atrazine in biologically active granular activated carbon
Authors: Selim Mustafa I. , Wang Jun 
Published: March 2010

Abstract
The fate of atrazine in biologically active laboratory-scale granular activated carbon (GAC) reactors was studied through analysis of atrazine and its breakdown products in the influent and effluent water of the GAC reactor and sand reactor. The biological activity in the GAC bed, influent, and effluent was monitored by measuring the heterotrophic plate count (HPC) bacteria. The HPC reached equilibrium concentrations of 1.37 to 1.67 × 106 colony-forming units per milliliter (cfu/ml) after two to three weeks in the GAC effluents, and 7.65 × 103 cfu/ml after four to six weeks in the effluent of the sand reactor. A solution of natural ground water spiked with 200 μg/L atrazine was continuously applied to the biologically active reactors at a flow rate of 5 ml/min for 70 d. Composite weekly samples of the effluent were extracted and analyzed for atrazine, deethylatrazine, and deisopropylatrazine using GC. Hydroxyatrazine was analyzed by liquid chromatography. Deethylatrazine was consistently detected in the effluent of the sand reactor only, and hydroxyatrazine was detected in the effluent of one of the GAC reactors, before complete development of bacterial activity. The percentage of atrazine disappearance was 98.10 to 98.67% in the GAC reactors and 42.10% in the sand reactor. The results suggest the possibility of complete mineralization of atrazine at 200 μg/L in biologically active GAC, with significantly low exportation of toxic breakdown products to the effluent water.
Effects of water temperature on the toxicity of 4-nitrophenol and 2,4-dinitrophenol to developing rainbow trout (Oncorhynchus mykiss)
Authors: Howe George E. , Marking Leif L. , Bills Terry D. , Boogaard Michael A. , Mayer Foster L. 
Published: March 2010

Abstract
Early-life-stage (ELS) toxicity tests were conducted to determine the effect of selected water temperatures on the toxicity of 4-nitrophenol and 2,4-dinitrophenol to rainbow trout (Oncorhynchus mykiss). NOECs were determined for growth and mortality at selected time intervals and water temperatures of 7, 12, and 17°C. As tests progressed, NOECs leveled to constant time-independent values that were similar for tests at each temperature. In 4-nitrophenol tests, the time-independent NOEC values at 7, 12, and 17°C, respectively, were 1.16, 1.20, and 1.16 mg/L for growth and 3.40, 3.38, and 2.20 mg/L for mortality. For 2,4-dinitrophenol, time-independent NOEC values at 7, 12, and 17°C, respectively, were 1.07, 0.50, and 0.80 mg/L for growth and 1.30, 1.89, and 1.60 mg/L for mortality. Temperature did, however, affect the rate at which time-independent NOECs were reached. More time was required to reach time-independent NOECs as temperature decreased. For example, the time-independent NOEC in 4-nitrophenol tests at 17°C was reached in 14 d, whereas it required 42 d at 7°C. The effect of temperature on toxicity must be considered in hazard assessment protocols to assess risk accurately and protect aquatic organisms adequately. Chronic toxicity tests are necessary to assess risk because acute toxicity tests cannot provide the information necessary to predict the long-term effects of factors such as temperature in natural environments.
Occurrence of non-ortho-, mono-ortho- and di-ortho-substituted PCB congeners in different organs and tissues of polecats (Mustela putorius L.) from the Netherlands
Authors: Leonards Pim E.G. , van Hattum Bert , Cofino Wim P. , Th. Brinkman Udo A. 
Published: March 2010

Abstract
The presence and concentrations of non-ortho-, mono-ortho-, and di-ortho-substituted PCB congeners in the polecat (n = 7), a member of the mustelid family, were investigated. PCBs were extracted with a Soxhlet apparatus. After cleanup the non-ortho-substituted PCB congeners were separated from the other PCBs by HPLC. Determinations were accomplished with GC-ECD or GC-MSD. Patterns of PCBs were examined in different organs and tissues: liver, kidney, muscle, anal gland secretion, mesenteric fat, and subcutaneous fat. Using a multivariate statistical method for data analysis (SIMCA), a significant difference of PCB patterns between anal gland secretion and the other organs and tissues was revealed. Lesser concentrations of congeners with seven and eight chlorine atoms in anal gland secretion were mainly responsible for this phenomenon. A more or less organ- and tissue-specific PCB pattern was observed in all animals. PCB patterns were not dependent on prey choice, which ranged from terrestrial (small rodents) to aquatic (amphibians). This finding implies that PCB patterns in the polecat seem to be controlled by metabolic processes rather than diet factors. The total concentration of PCBs (sum of 29 congeners) in polecats varies widely, two orders of magnitude, from 1 to 370 μg/g lipid. In some animals, PCBs exceeded the experimentally determined reproduction effect concentrations of mink and ferrets. Using the toxic equivalent approach, it was observed that planar PCB 126 accounts for 63 to 98% of the toxic equivalents. The results showed that juvenile animals contain greater PCB levels than adult males and females, which might be related to an increased elimination of PCBs in adult animals due to anal gland secretion. High concentrations of PCBs were observed in such secretion. A preliminary model for concentrations of PCBs in polecats including this effect is proposed.
Effects of Bacillus thuringiensis var. Israelensis on nontarget benthic organisms in a lentic habitat and factors affecting the efficacy of the larvicide
Authors: Charbonneau Colette S. , Drobney Ronald D. , Rabeni Charles F. 
Published: March 2010

Abstract
Field and laboratory studies were conducted to determine the effects of Bacillus thuringiensis var. israelensis (Vectobac-G®) on waterfowl macroinvertebrate food resources at the Minnesota Valley National Wildlife Refuge, Bloomington, Minnesota. Laboratory toxicity tests were conducted to evaluate the influence of environmental variables (e.g., temperature and depth). The EC50 was 0.20 ppm for Chironomus riparius. Field studies evaluated the effects of three applications at 5.6 kg/ha on ben-thic communities during the spring and summer of 1989, and three experiments with one application of 5.6 kg/ha and 28.1 kg/ha during the spring and summer of 1990. Benthic invertebrates were sampled before each application of Vectobac-G and at 48 h after application. There was no reduction of the major taxa found in the ponds that could be accounted for by the treatments. However, results from laboratory toxicity tests conducted with field-collected Chironomidae indicated that these organisms were affected at 5.6 and 28.1 kg/ha. Further toxicity tests using Chironomus riparius determined that various environmental variables influenced the efficacy of Vectobac-G, including temperature, larval instar, water depth, and water surface area coverage by macrophytes. This study indicates that chironomids (a major waterfowl food source) are adversely affected by Vectobac-G under a controlled laboratory situation; however, environmental factors reduce the efficacy of the larvicide in the field.
Environmental effects on wetlands of queletox® applied to ploceid roosts in Kenya
Authors: Keith James O. , Bruggers Richard L. , Kimball Bruce A. , Ngondi John G. , Elliott Clive C.H. 
Published: March 2010

Abstract
Queletox® (Fenthion) is widely used in Africa to kill birds that eat cereal crops. Applications of Queletox have been reported to kill nontarget animals and contaminate areas used by livestock and humans. In 1988, we evaluated Queletox treatments to wetland roosts at the Njoro dam (2.88 kg/ha) and Gicheha farm (12.0 kg/ha) near Nakuru, Kenya. Fenthion deposits measured in the roosts ranged up to 1,100 g/ha, but were &gt;1 0 g/ha at distances of 100 m or more from roosts. Following applications, 61 birds of 14 species at the Njoro dam and 22 birds of eight species at the Gicheha farm were found dead or severely debilitated. However, the general abundance of waterfowl, wading birds, plovers, doves, and passerines seemed unaffected. Residues in crop contents of 11 dead birds ranged up to 11.0 ppm, substantiating death from fenthion. Fenthion residues (2.2-750 μg) recovered from skin and feathers of 36 dead birds were sufficient to have been hazardous to predators and scavengers. Neither amphibians nor fishes were affected by treatments. At the Njoro dam, scarabids, dytiscids, and notonec-tids were killed, and their numbers decreased; many insects also were killed at the Gicheha farm. The abundance of these groups, however, had increased within 6 d post-treatment. Fenthion residues of 1.8 to 17 ppb were found in positive water samples for up to 5 d post-treatment. All sampled vegetation had temporarily hazardous residues; levels ranged up to 83 ppm on grasses but had decreased to &lt;1.0 after 3 d.
Structural responses of benthic macroinvertebrate communities from different stream orders to zinc
Authors: Kiffney Peter M. , Clements William H. 
Published: March 2010

Abstract
It is well established that benthic invertebrate community structure and function shift in a predictable fashion along longitudinal stream gradients as a result of variation in environmental conditions. Our research is concerned with experimentally testing whether this shift in community structure influences the response of benthic macroinvertebrates to heavy metals. Using artificial streams, we compared effects of Zn on natural assemblages of benthic macroinvertebrate communities collected from Little Beaver Creek (LBC; a third-order stream) and the Big South Fork of the Cache la Poudre River (SFP; a fourth-order stream) of the Cache la Poudre, Colorado, catchment. Organisms collected from LBC and SFP were exposed to 0 or 130μg/L Zn in indoor experimental streams for 7 d. In general, similar taxa were found at both sites, but densities were generally higher at SFP than at LBC. We observed significant effects at the community and population level as a result of Zn, stream order, and the interaction between Zn and stream order. Specifically, mayflies from both sites were sensitive to Zn, but the magnitude of the response varied between sites. Our results indicate that benthic macroinvertebrate communities from different stream orders may vary in sensitivity to Zn.