bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of dietary exposure to polychlorinated biphenyl 126 and nutritional state on stress response in tilapia (Oreochromis mossambicus) and rainbow trout (Oncorhynchus mykiss)
Authors: Quabius Elgar Susanne , Nolan Declan T , Allin Crystal J , Bonga Sjoerd E Wendelaar 
Published: March 2010

AbstractPolychlorinated biphenyls (PCBs) are highly toxic pollutantss ructurally resemblings eroidhormones, interfering with synthesis and action of gonadal and adrenocortical steroids, and impairing the cortisol- and adrenocorticotropic hormone (ACTH)-mediated stress response in fish. In this study on tilapia and rainbow trout, we analyzed the influence of dietary PCB on the response to a nontoxic stressor (confinement) as well as the influence of starvation following the PCB exposure on this response. Fish, in duplicate tanks, were fed diets containing 25 μg (low) or 2, 500 μg (high) of PCB 126 per kilogram of food per day for five days. After the exposure, fish from one control, low-PCB, and high-PCB diet tank were sampled directly or after confinement. Fish in the second group of these tanks were starved for three weeks to allow mobilization of stored PCBs and then sampled directly or after confinement. In fish sampled directly after the PCB exposure, basal hormone and glucose levels were not affected. After confinement, plasma cortisol rose to the same high levels in all groups. Adrenocorticotropic hormone levels in confined fish (both species) increased with increasing PCB load. Only fish fed the high-PCB diet showed impaired hyperglycemia. After starvation, only basal plasma glucose levels were lower in fish fed the high-PCB diet. All other parameters were unaffected in resting fish. Confining PCB-fed and starved fish resulted in elevated plasma hormone levels that were lower than in confined, starved control fish. Plasma glucose levels in starved and unstarved fish were similar. Morphometric analysis of head kidney interrenal cells revealed only subtle, species-specific changes. We conclude that PCB 126 has disruptive actions on the hormonal regulation of the stress response. Starving PCB-fed fish did not further impair the hyperglycemic response to confinement but did affect the ACTH- and cortisol-mediated responses to confinement. A poor nutritional status is concluded to enhance the negative effects of PCBs on the stress responsiveness of fish.
Evaluation of toxicity: Whole-sediment versus overlying-water exposures with amphipodHyalella azteca
Authors: Ingersoll Christopher G , Ivey Chris D , Brunson Eric L , Hardesty Doug K , Kemble Nile E 
Published: March 2010

AbstractA laboratory study was conducted to evaluate the toxicity of whole-sediment versus overlying-water exposures to the amphipod Hyalella azteca using field-collected sediments. Severe toxic effects (5–63% survival) were observed with amphipods exposed for 10 d in direct contact with sediment. In contrast, amphipods exposed only to overlying water in these sediment exposures did not exhibit any toxic effects.
Reproductive, immune, and physiological end points in tree swallows on reclaimed oil sands mine sites
Authors: Smits Judit E , Wayland Mark E , Miller Michael J , Liber Karsten , Trudeau Suzanne 
Published: March 2010

AbstractWild nestling tree swallows (Tachycineta bicolor) inhabiting reclaimed wetlands receiving tailings or water from mine tailings ponds on oil sands mine sites were the subjects in a multiyear study to determine the ecological viability of these areas. Spanning two field seasons, immune function, reproductive performance (clutch size and mass, hatching success), nestling growth and survival, and diet of tree swallows were examined on six wetlands. One aspect of immune function, the T-lymphocyte proliferative response, was assessed in vivo using a phytohemagglutinin skin test. Hepatic ethoxyresorufin-O -deethylase (EROD) activityprovided a biomarker of exposure to oil sands contaminants in the tree swallow nestlings. Results show that there were no differences among reclaimed wetland sites for tree swallow reproductive success, nestling growth rate, and immune response that could be attributed to tailings or tailings pond water additions. Increased EROD activity confirmed the presence of xenobiotics in the diets of nestlings from two sites, while the main reference site was relatively free of EROD-inducing compounds. Dietary analyses showed that 84% of the food items of the tree swallow nestlings were of aquatic origin, likely from the local wetlands, and thus would be expected to provide a good reflection of biological effects of any mining-related contaminants accumulating through the food chain.
Effects of atrazine on amphibian growth and survival in artificial aquatic communities
Authors: Diana Stephen G , Resetarits William J , Schaeffer David J , Beckmen Kimberlee B , Beasley Val R 
Published: March 2010

AbstractAificial pond microcosms with pond water, including phytoplankton, periphyton, macrophytes, and larval gray tree frogs (Hyla versicolor), were treated with atrazine to achieve final aqueous concentrations of 0, 20, 200, or 2, 000 μg/L. Dissolved oxygen concentrations (DO) decreased to approx. 20 to 40% of their preexposure values in the 200- and 2, 000-μg/L treatment groups within 1 d of atrazine addition. Dissolved oxygen in these microcosms returned to control concentrations by 10 d after exposure but declined again to approximately 60 to 80% of control values at 21 d after exposure and remained depressed for the remainder of the study. In the 200- and 2, 000-μg/L treatment groups, pH decreased similarly within 1 d of atrazine exposure and returned to control values within the following 16 d. The DO and pH did not differ significantly between the 0- and 20-μg/L groups or the 200- and 2, 000-μg/L groups. Frogs from the two higher atrazine concentration treatment groups were 5% shorter and had 10% lower body mass at metamorphosis than those from the control and low atrazine concentration groups. No difference in length or body mass at metamorphosis was detectable between the 0- and 20-μg/L groups or between the 200- and 2, 000-μg/L groups. Larval period was 5% longer in the 2, 000-μg/L group than in the 200-μg/L group but did not differ from controls in any treatment group. No significant treatment-related differences were detected for survival rate. The decrease in amphibian length and weight at metamorphosis may indicate a reduction in fitness in wild populations of anurans exposed to atrazine at 200 to 2, 000 μg/L.
Use of nonlinear regression techniques for describing concentration-response relationships of plant species exposed to contaminated site soils
Authors: Stephenson Gladys L , Koper Nicola , Atkinson Glenn F , Solomon Keith R , Scroggins Richard P 
Published: March 2010

Abstract
The objectives of this study were to examine the effects of two contaminated site soils on seedling emergence and growth, compare the responses of different endpoints and species sensitivity, and develop appropriate statistical methods for the analysis of concentration-response curves. Plants were exposed to field-collected soils contaminated with amines or condensate. We reparameterized three nonlinear models (logistic, logistic with hormesis, and exponential) to determine any inhibiting concentration for a specified percent effect and confidence interval using regression analysis. Weighting procedures were applied, when necessary, to accommodate heteroscedasticity. This nonlinear regression approach was very satisfactory when used with data sets, each with 11 treatments, and produced an accurate, easily interpreted, and quantitative description of the data, which also provided qualitative information. The IC50s ranged from 2 to 96% contamination for condensate-contaminated soil and from 3 to 38% contamination for amine-contaminated soil. The responses were specific to species, endpoint, and soil. Mass measurements were generally more sensitive and precise than length measurements. Definitive tests were more sensitive than acute tests for endpoints other than emergence.
Effects of two grasshopper control insecticides on food resources and reproductive success of two species of grassland songbirds
Authors: Martin Pamela A , Johnson Dan L , Forsyth Douglas J , Hill Bernard D 
Published: March 2010

Abstract
Wconducteda field experimenttodetermine the direct and indirect effects of spraying two broad-spectrum insecticides with widely differing avian toxicities in grassland habitat on the survival and reproductive success of nesting songbirds. Three 56-ha plots were sprayed with Decis 5F™, three plots were sprayed with Furadan 480F™, and three plots were left unsprayed. Insecticides were applied at rates recommended for grasshopper control. Grasshopper (Orthoptera: Acrididae) density was measured throughout the spring and summer. Nests of chestnut-collared longspurs (Calcarius ornatus) were monitored to determine survival rates and nestling growth. Food habits of nestlings and parental foraging parameters were measured using esophageal ligatures and observations of parental foraging flights. Applications of both insecticides decreased grasshopper populations by more than 90%. Nevertheless, the number of grasshoppers in nestling diets was significantly decreased only in nests in Decis-sprayed plots. Total arthropod biomass delivered to the nestlings did not decrease in plots sprayed with either insecticide. Nestling weight and size were unaffected by insecticide spraying. Rate of prey delivery also did not change; however, by two weeks after spraying with Decis, parent longspurs were foraging almost twice as far from their nests as were birds in control plots (p &lt; 0.05) to maintain prey delivery rates. Clutch size and egg and nestling success were similar among treated and control plots within specific two-week periods during the season. Age-corrected brain acetylcholinesterase activities of longspur nestlings in plots sprayed with Furadan were significantly depressed compared to controls; a single case of insecticide-induced mortality was detected in a nestling that was severely infested with blowfly larvae. Nevertheless, success of nests with Furadan-exposed nestlings (n = 20) was greater than that in control plots during the two-week period following spray (n = 19, p = 0.03). The Baird's sparrow (Ammodramus bairdii), an uncommon prairie species of conservation concern, was monitored using an index of productivity. The number of 3.14-ha census circles having productive Baird's sparrow territories was significantly lower in Furadan-sprayed plots than in unsprayed and Decis-sprayed plots; a larger number of sparrow territories were abandoned in Furadan plots.
Seasonal changes in acute toxicity of cadmium to amphipod Corophium volutator
Authors: Kater Belinda J , Hannewijk André , Postma Jaap F , Dubbeldam Marco 
Published: March 2010

Abstract
In vivo bioassays are frequently used to assess the ecotoxicological risks of contaminated sediments. For quality assurance purposes, these bioassays are accompanied by reference toxicity tests. For the bioassay with Corophium volutator, this reference toxicity test is an acute water-phase test with cadmium. Approximately 80 water-phase tests were conducted in the period 1991–1998. Corophium volutator shows a significant seasonal variation in response to cadmium, with a high LC50 in the winter period and a low LC50 in the summer period. Same variation can be found if Corophium is held in the laboratory instead of freshly collected in the field and if synthetic water is used instead of natural filtered seawater. The observed seasonal variation is not caused by the fact that the organisms are collected in the field or by the variation in seawater used for the water-phase tests.
Acetylcholinesterase inhibition in estuarine fish and invertebrates as an indicator of organophosphorus insecticide exposure and effects
Authors: Fulton Michael H , Key Peter B 
Published: March 2010

Abstract
The majority of insecticidescurrently in use are organophosphorus, carbamate, and synthetic pyrethroid compounds. Organophosphorus insecticides (OPs) produce toxicity by inhibiting the cholinesterase enzymes in the nervous system. Monitoring of acetylcholinesterase (AChE) inhibition has been widely used in terrestrial and freshwater aquatic systems as an indicator of OP exposure and effects. This review describes the use of AChE inhibition as a biomarker in the estuarine environment, discusses the relationship between AChE inhibition and other manifestations of OP toxicity, and highlights areas where additional research is needed. A variety of studies with estuarine fish have suggested that brain AChE inhibition levels of &gt;70% are associated with mortality in most species. Selected species, however, appear capable of tolerating much higher levels (&gt;90%) of brain inhibition. Sublethal effects on stamina have been reported for some estuarine fish in association with brain AChE inhibition levels as low as 50%. Most studies suggest, however, that these effects are observed only when brain AChE inhibition is at near-lethal levels. A number of field studies have successfully used AChE inhibition in fish as a biomarker in the estuarine environment. The use of AChE inhibition as a biomarker in estuarine invertebrates has been less well studied. Although AChE inhibition has been measured in the tissues of a variety of invertebrate species following OP exposure, the relationship between AChE inhibition and lethality is less distinct. Additional work is needed in both fish and invertebrates to better explain species-specific differences in the relationship between AChE inhibition and mortality and to investigate other physiological perturbations associated with AChE inhibition.
Maternal transfer of contaminants: Case study of the excretion of three polychlorinated biphenyl congeners and technical-grade endosulfan into eggs by white leghorn chickens (Gallus domesticus)
Authors: Bargar Timothy A , Scott Geoffrey I , Cobb George P 
Published: March 2010

Abstract
Reportedavian maternal transfer ratesof organochlorine contaminants range from 1% to as much as 20% of maternal body burdens. However, to our knowledge, no investigation of factors governing maternal transfer has been reported. Here, we report an investigation of maternal transfer of 2,3,3′,4,4′-pentachlorinated biphenyl (PCB 105), 2,3,3′,4,4′,5-hexachlorinated bi-phenyl (PCB 156), 2,3,3′,4,4′,5,5′-heptachlorinated biphenyl (PCB 189), and technical-grade endosulfan into eggs by white leghorn chickens (Gallus domesticus). Two experiments were performed to evaluate individual chemical excretion into eggs when hens were injected with each chemical individually (experiment one) or with a mixture of all four chemicals (experiment two). Each hen was injected subcutaneously every 4 d during a 21-d period with 100 μl of the dosing solution during both experiments. The mass of each chemical excreted into the egg was compared among eggs and with the mass injected into hens to determine the influence of chemical structure (experiment one) and interaction (experiment two) on maternal transfer of those chemicals into eggs. Maternal transfer of PCBs was inversely related to congener chlorination. The congener mass in eggs, as a percentage of the mass injected into hens, was 0.42% for PCB 189, 0.54% for PCB 156, and 0.61% for PCB 105. In experiment two, absolute excretion of only PCB 189 and α-endosulfan into eggs was affected by the presence of other chemicals. Excretion of PCB 189 (0.51%) and α-endosulfan (0.03%) increased and decreased, respectively, compared with when they were individually injected into hens during experiment one. Lastly, much less of the more metabolically susceptible endosulfan (0.04–0.12% of the mass injected) was excreted into the egg relative to PCBs, despite being injected into the hens at concentrations comparable with those of PCBs, suggesting, at least in avian species, lower maternal transfer of more metabolically susceptible chemicals.
Toxicity of aqueous-phase and suspended particle-associated fenvalerate: Chronic effects after pulse-dosed exposure ofLimnephilus lunatus(Trichoptera)
Authors: Schulz Ralf , Liess Matthias 
Published: March 2010

AbstractNon-point source pollution of agricultural surface waters via spraydrift and runoff can lead to different short-term exposure scenarios: contamination with water-dissolved or particle-associated pesticide. To compare water-dissolved and particle-associated exposure, fenvalerate (FV) was tested in a 1-h exposure setup with suspended silt particles (5 g dry wt/L; total organic carbon = 3.2%). Chronic effects on the test organism Limnephilus lunatus Curtis (Trichoptera), second and third instar, were observed more than 240 d after transfer of larvae into an outdoor-stream microcosm with pesticide-free water. Significant-effect concentrations were 0.001 μg/L in water and 0.2 μ.g/kg in suspended sediments. Toxicity is lower in the presence of suspended particles by factors between 100 (using mortality and production of biomass as endpoints) and 10 (using emergence pattern and dry wt of adults as endpoints). Effect levels were generally lower than those in previous studies using older larval stages. The reduction of adult dry weight may diminish reproductive success. Aqueous-phase contamination caused lethal and sublethal effects at concentrations of FV that can be measured in the field. In contrast, levels of particle-associated FV that are relevant to the field situation elicited only sublethal responses in the present experiment. Results from this study suggest that short-term FV contamination at expected, field-relevant levels may lead to long-term effects even if the chemical is associated with suspended particles.
Photodegradation of the pharmaceutical drug diclofenac in a lake: Pathway, field measurements, and mathematical modeling
Authors: Poiger Thomas , Buser Hans-Rudolf , Müller Markus D 
Published: March 2010

Abstract
Vertical concentration profiles of diclofenac were measured in Lake Greifensee (Switzerland) under mixed (February/December) and stratified (July) lake conditions. The concentrations ranged from 1 to 12 ng/L and were lower in summer than in winter, especially near the lake surface, pointing to an efficient elimination of diclofenac by photodegradation in the lake. Laboratory experiments confirmed the rapid photodegradation of diclofenac in water when exposed to sunlight. First-order reaction rates varied seasonally according to actual solar radiation (half-lives, τ = 0.2–1.7 h). The initial photoproduct was 8-chlorocarbazole-1-acetic acid, which photodegraded even faster than the parent compound. Carbazole-1-acetic acid, previously reported as the main photoproduct, was only formed in the presence of a H-source, such as methanol. In the absence of a H-source and of air, hydroxycarbazole-1-acetic acid was formed. However, hydroxycarbazole-1-acetic acid was not observed in the presence of air and, thus, under conditions similar to those in a lake, likely because of its rapid further photooxidation. Computer simulations using a one-dimensional lake model taking actual solar radiation and flushing data of the lake into account confirmed that photolysis is the predominant elimination pathway for diclofenac in Lake Greifensee. These calculations further showed that the expected concentrations of the photoproduct 8-chlorocarbazole-1-acetic acid are less than the current detection limits of approximately 3 ng/L.
Diffuse geographic distribution of herbicides in northern prairie wetlands
Authors: Donald David B , Gurprasad Narine P , Quinnett-Abbott Lynne , Cash Kevin 
Published: March 2010

Abstract
The concentrations of herbicides in water from wetlands on landscapes where herbicides are not used should be less than on farms with moderate (conventional farms) and intense (minimum-till farms) herbicide use. In general, this hypothesis was not supported for wetlands situated in the Boreal Plains Ecozone of central Saskatchewan, Canada. The overall detection frequency of 10 commonly used herbicides was not significantly different among wildlife habitat with no pesticide use (44.4%), farms with no pesticide use (51.6%), conventional farms (54.9%), and minimum-till farms (56.5%, χ2 = 5.64, p = 0.13). The herbicides (4-chloro-2-methylphenoxy) acetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D), bromoxynil, dicamba, mecoprop, and diclorprop accounted for 87% of all detections. In general, detection frequencies and concentrations of individual herbicides were similar on all land-use types. For example, the mean concentration of 2,4-D in water on the four land types ranged from 0.12 ± 0.104 to 0.26 ± 0.465 μg/L, and MCPA ranged from 0.08 ± 0.078 to 0.19 ± 0.166 μg/L. However, in the year of application, mean concentrations of MCPA and bromoxynil, but not 2,4-D, were significantly higher by about twofold in wetlands situated in fields where these herbicides were applied compared with all other wetlands. We propose that many agricultural pesticides are rapidly lost to the atmosphere at the time of application by processes such as volatilization from soil and plant evapotranspiration. Then, the herbicides used throughout the region may be directly absorbed to the surface of wetlands from the atmosphere, or they become entrained in local convective clouds, and are redistributed by rainfall in a relatively homogenous mixture over the agricultural landscape. The low levels of individual herbicides we found in most of the wetland waters would not cause chronic effects to aquatic biota.
Integration of genotoxicity and population genetic analyses in kangaroo rats (Dipodomys merriami) exposed to radionuclide contamination at the Nevada Test Site, USA
Authors: Theodorakis Christopher W , Bickham John W , Lamb Trip , Medica Philip A , Lyne T Barrett 
Published: March 2010

Abstract
We examined effects of radionuclide exposure at two atomic blast sites on kangaroo rats (Dipodomys merriami) at the Nevada Test Site, Nevada, USA, using genotoxicity and population genetic analyses. We assessed chromosome damage by micronucleus and flow cytometric assays and genetic variation by randomly amplified polymorphic DNA (RAPD) and mitochondrial DNA (mtDNA) analyses. The RAPD analysis showed no population structure, but mtDNA exhibited differentiation among and within populations. Genotoxicity effects were not observed when all individuals were analyzed. However, individuals with mtDNA haplotypes unique to the contaminated sites had greater chromosomal damage than contaminated-site individuals with haplotypes shared with reference sites. When interpopulation comparisons used individuals with unique haplotypes, one contaminated site had greater levels of chromosome damage than one or both of the reference sites. We hypothesize that shared-haplotype individuals are potential migrants and that unique-haplotype individuals are potential long-term residents. A parsimony approach was used to estimate the minimum number of migration events necessary to explain the haplotype distributions on a phylogenetic tree. The observed predominance of migration events into the contaminated sites supported our migration hypothesis. We conclude the atomic blast sites are ecological sinks and that immigration masks the genotoxic effects of radiation on the resident populations.