bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary absorption efficiencies and toxicokinetics of polychlorinated biphenyls in ring doves following exposure to aroclor® mixtures
Authors: Drouillard Ken G , Norstrom Ross J
Published: March 2010

Ring doves (Streptotpelia risoria) were fed a meal of pellets spiked with an Aroclor® mixture. Feces were collected from birds after fasting 31 h postexposure and dietary absorption efficiencies (AbE) of polychlorinated biphenyls (PCBs) were determined by mass balance. Polychlorinated biphenyl AbEs ranged from 0.86 to 0.97 for individual congeners and were similar to the lipid AbE of 0.90. The AbEs exhibited a declining trend with increasing chemical hydrophobicity. The toxicokinetics of PCBs and dietary lipids in blood plasma were also followed in the exposed birds for 25 h after feeding the contaminated meal. Despite decreasing trends in net AbEs with increasing chemical hydrophobicity, all PCBs exhibited similar blood toxicokinetics as observed for dietary lipids. The PCB plasma uptake rate constants exhibited a positive correlation with chemical hydrophobicity such that the most hydrophobic congener PCB 180 approached the plasma uptake rate constant measured for dietary lipids. Trends in assimilation kinetics of PCBs in blood were not consistent with the general prediction that solubility limitations of chemicals in the unstirred water layer (UWL) contribute to declines in net AbEs for highly hydrophobic chemicals. The data are consistent with a micelle-mediated diffusion model, which indicates that dietary lipids and hydrophobic contaminants can cross the UWL and enter intestinal tissues at equivalent rates; however, solubility limitations of highly hydrophobic chemicals in mixed micelles may contribute to decline in net AbEs.
Effects of contaminated sediment on the epidermis of mummichog, Fundulus heteroclitus
Authors: Mézin Laurent C , Hale Robert C
Published: March 2010

Secretion of mucus by epidermal goblet cells protects fish against many biological, physical, and chemical insults encountered in the environment. This study monitored changes in hemoglobin concentration in epidermal mucus and in the density, diameter, and mucus quality of epidermal goblet cells in the mummichog, Fundulus heteroclitus, following exposure to creosote-contaminated sediment from the Elizabeth River, Virginia, USA. Fish were exposed for 13 d in flow-through aquaria to either uncontaminated (US) or contaminated (CS) sediments and were sampled periodically. The condition index was lower and the mortality rate and the occurrence of epidermal lesions were higher in CS-exposed fish than in US-exposed fish. Hemoglobin contents in epidermal mucus from the former group were significantly higher than from the latter. Significant reductions in both size and density of goblet cells in CS-exposed fish suggested a mucus secretion rate exceeding its production rate. Significant changes in mucin types between treatments did not occur until day 13 and are not believed to be directly related to the creosote present in the contaminated sediment. These results all indicate that exposure to creosote-contaminated sediment had a profound and deleterious effect on fish health.
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

Polychlorinated 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

A 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

Wild 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

Aificial 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

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

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 < 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

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

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 >70% are associated with mortality in most species. Selected species, however, appear capable of tolerating much higher levels (>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

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

Non-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

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

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

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.
Phytotoxicity of chlorinated aliphatics to hybrid poplar (Populus deltoides × nigraDN34)
Authors: Dietz Annette C , Schnoor Jerald L
Published: March 2010

Effects of a series of chlorinated ethenes and ethanes on hybrid poplar (Populus deltoides × nigra DN34) were assessed in laboratory experiments. Poplar cuttings were grown in sealed reactors with hydroponic solutions and were exposed to a chlorinated solvent for a period of two weeks. Exposure concentrations ranged from 0 to 0.4 mM for perchloroethylene to 0 to 8.4 mM for 1,1-dichloroethane. Effects were assessed by gravimetrically monitoring transpiration and measuring change in cutting mass. The zero-growth concentrations of the chemicals tested were 0.3 mM perchloroethylene, 0.9 mM trichloroethylene, 0.9 mM 1,1,2,2-tetrachloroethane, 2.0 mM 1,1,1-trichloroethane, 2.3 mM 1,1,2-trichloroethane, 4.8 mM trans-dichloroethylene, 5.6 mM 1,1-dichlor-oethylene, 6.0 mM cis-dichloroethylene, and 10.7 mM 1,1-dichloroethane. Adverse effects were found to increase with increasing number of chlorine atoms within a homologous series of ethenes or ethanes. Ethenes were more toxic than similarly chlorinated ethanes.
Response of bobwhite quail and gray-tailed voles to granular and flowable diazinon applications
Authors: Wang Guiming , Edge W Daniel , Wolff Jerry O
Published: March 2010

We used gray-tailed voles (Microtus canicaudus) and northern bobwhite quail (Colinus virginianus) as experimental model species to field test whether small mammals and birds respond differently to equivalent concentrations of a pesticide applied in granular and flowable formulations. In mid-May 1998, we placed voles into 15, 0.2-ha enclosures planted with a mixture of pasture grasses. In mid-July, we placed quail into the same enclosures with the voles. In late July, we applied the organophosphorus insecticide diazinon in five treatments; a control (all habitats sprayed with water), liquid formulation of diazinon at 0.55 kg/ha, liquid formulation of diazinon at 1.11 kg/ha, broadcast of granular diazinon at 1.11 kg/ha, and broadcast of granular diazinon at 2.22 kg/ha. The diazinon treatment in liquid and granular formulations did not depress population size or growth rate, or survival rate of voles. We found a significant difference in the survival rate of the quail between the controls and treatments; granular diazinon caused a measurable decline of quail survival, whereas the liquid application at an equivalent rate did not significantly affect quail survival. Analysis of our results suggests that ground-feeding birds are more susceptible to granular insecticides than flowable applications, but voles were not susceptible to either formulation at the rate we used.
Adding magnesium to the silver-gill binding model for rainbow trout (Oncorhynchus mykiss)
Authors: Schwartz Melissa L , Playle Richard C
Published: March 2010

Rainbow trout (Oncorhynchus mykiss; 2–17 g) were exposed to approximately 0.1 μM silver as AgNO3 for 3 to 4 h in synthetic, ion-poor water (20 μM Ca, 100 μM Na, 150 μM Cl, pH 7) to which was added Mg, Ca, or thiosulfate (S2O3). Gills were extracted and assayed for Ag using graphite furnace atomic absorption spectrophotometry. Up to 210 mM Mg (four fold the concentration of Mg in seawater) did not reduce accumulation of Ag by trout gills. The conditional equilibrium stability constant (K) for Mg at silver-binding sites on the gills was calculated to be log KMg-gillAg = 3.0, or approximately half-as-strong binding as for Ca at these sites. The inclusion of the Mg-gill stability constant into the original Ag-gill binding model increases the flexibility of the model, although the competitive effects of Mg are only important in sodium-poor systems.
Structure–activity relationship study on the bioreduction of AZO dyes by Clostridium paraputrificum
Authors: Moir David , Masson Sheila , Chu Ih
Published: March 2010

Seven commercially available, structurally related azo dyes have been bioreduced by the anaerobic bacterium Clostridium paraputrificum. The rates of reduction of these dyes were found to vary between 24 and 74 nmoles reduced/mg protein/h. Acid red 1 and desmethyl acid red 106 were found to be the most readily reduced, while chromotrope 2R and cibacron brilliant red 3B-A were reduced at the slowest rates. The differences in reduction rates can be rationalized on the basis of structural differences and are consistent with the possible intermediacy of low molecular-weight electron carriers as the mediators of reduction. The incorporation of electron-withdrawing groups into the dyes, even if remotely placed, was found to increase the rate of reduction of dyes under controlled conditions, supporting the inversely proportional relationship between the electron density of the azo bond and the ease of bioreduction.
Differential induction of glutathione S-transferases in the clamruditapes decussatusexposed to organic compounds
Authors: Hoarau Pascal , Gnassia-Barelli Mauricette , Romeo Michèe , Girard Jean-Pierre
Published: March 2010

Studies of glutathione S-transferase (GST) induction were performed in the Mediterranean clam Ruditapes decussatus after controlled exposure to organics in holding tanks. Clams were treated with phenobarbital (PB), benzo[a]pyrene (BaP), and 2,2-bis-(p-chlorophenyl)-1,1-dichlorethylene (p,p′-DDE). Three different substrates, i.e., 1-chloro-2,4-dinitrobenzene (CDNB), ethacrynic acid (ETHA), and paranitrobenzene chloride (PNBC), were used to determine GST activities in order to distinguish the isoenzymes induced by contamination. The isoforms conjugating ETHA were significantly induced by treatment with PB and BaP whereas exposure to p,p′-DDE induced isoforms conjugating CDNB and ETHA. An antibody against affinity-purified GSTs from R. decussatus was prepared by injection into rabbit. The serum containing the antibody gave a positive reaction with both the purified GSTs from R. decussatus and the low molecular weight GSTs from rat. Subcellular fractions from both control and treated animals were analyzed by Western blot. Cytosolic extracts from clams contaminated with PB and p,p′-DDE showed a 24-kDa band in addition to the 26-kDa band recognized by the antibody. Results of these studies suggest that, in R. decussatus, organics may induce GSTs belonging to the π class.
Effects of chronic Cd exposure via the diet or water on internal organ-specific distribution and subsequent gill Cd uptake kinetics in juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Szebedinszky Cheryl , McGeer James C , McDonald D Gordon , Wood Chris M
Published: March 2010

New regulatory approaches to metal toxicity (e.g., biotic ligand model [BLM]) focus on gill metal binding and tissue-specific accumulation of waterborne metals; the dietary route of exposure and dietary/waterborne interactions are not considered, nor are the consequences of chronic exposure by either route. Therefore, we studied the effect of the same gill Cd load (∼2.5 μg/g), achieved by a chronic, 30-d exposure to Cd either via the diet (1,500 mg/kg) or the water (2 μg/L), on tissue-specific Cd distribution and subsequent uptake of waterborne Cd in juvenile rainbow trout (Oncorhynchus mykiss). These two exposure regimes resulted in a branchial Cd load that had been taken up across either apical gill membranes (waterborne Cd) or basolateral gill membranes (through the bloodstream for dietary Cd). The BLM characteristics of the gills (i.e., short-term Cd uptake kinetics) were altered: affinity (log KCd-Gill [95% confidence level]) decreased from 7.05 (6.75–8.76) for control to 6.54 (6.32–7.03) for waterborne Cd and 5.92 (5.83–6.51) for dietary Cd, whereas binding capacity (Bmax) increased from 3.12 (2.14–4.09) to 4.80 (3.16–6.43) and 5.50 (2.86–8.17) nmol·g−1 for control, waterborne, and dietary Cd, respectively. Fish exposed to dietary Cd accumulated a much greater overall chronic Cd body burden relative to fish exposed to waterborne Cd or control fish. The carcass accumulated the greatest percentage of total body Cd in control and waterborne-exposed fish, whereas the intestinal tissue accumulated the greatest percentage in dietary-exposed fish. Tissue-specific Cd burdens were highest in the kidney in both dietary and waterborne treatments. We conclude that chronic Cd exposure alters Cd uptake dynamics, and that the route of Cd exposure, whether waterborne or dietary, results in differences of internal Cd accumulation and branchial Cd uptake characteristics. These factors should be considered in future BLM development.
Separation and characterization of gall bladder bile metabolites from speckled trout,Salvelinus fontinalis, exposed to individual polycyclic aromatic compounds
Authors: Leonard James D , Hellou Jocelyne
Published: March 2010

Speckled trout, Salvelinus fontinalis, were orally exposed to individual polycyclic aromatic compounds (PACs) represented by benzo[a]pyrene, carbazole, chrysene, dibenzofuran, dibenzothiophene, fluorene, phenanthrene, and pyrene. Fish were sacrificed 7 d after exposure and the gall bladder removed for bile analysis. High pressure liquid chromatography (HPLC) with fluorescence (F) and ultraviolet (UV) detection was used to determine the presence of PAC derivatives in the bile without pretreatment. Glucuronide conjugates were predominant in all exposures with variable amounts (0–53%) of phenols and starting material. Identification of compounds was confirmed by selective extraction of less polar nonconjugated PACs and enzymatic hydrolysis of water-soluble material. This was followed by HPLC and/or gas chromatography-mass spectrometry (GCMS) characterization of the produced phenols. Total metabolite levels varied widely among compounds.
Polycyclic aromatic hydrocarbons, aliphatic hydrocarbons, trace elements, and monooxygenase activity in birds nesting on the North Platte River, Casper, Wyoming, USA
Authors: Custer Thomas W , Custer Christine M , Dickerson Kimberly , Allen Kenneth , Melancon Mark J , Schmidt Larry J
Published: March 2010

Tree swallow (Tachycineta bicolor) and house wren (Troglodytes aedon) eggs and chicks were collected near a refinery site on the North Platte River, Casper, Wyoming, USA and at a reference site 10 km upstream. Total polycyclic aromatic hydrocarbon (PAH) concentrations in swallow and wren chicks were higher at the refinery site than at the reference site. Polycyclic aromatic hydrocarbon concentrations in sediment and chick dietary samples were consistent with these findings. The general lack of methylated PAHs in sediment, diet, and bird carcasses suggested that the PAHs were derived from combustion and not from petroleum. The predominance of odd-numbered aliphatic hydrocarbons and the low ratios (≤0.25) of pristane:n-C17 and phytane:n-C18 in chick and diet samples also suggested that swallow and wren chicks were not being chronically exposed to petroleum. Mean ethoxyresorufin-O-dealkylase and benzyloxyresorufin-O-dealkylase activities in tree swallow livers averaged nine times higher at the refinery site than at the reference site and were probably induced by exposure to PAHs. Trace element concentrations in eggs and livers of swallows and wrens were similar or greater at the reference site than at the refinery site. Selenium, strontium, and boron concentrations were elevated in eggs and livers of swallows and wrens at both the refinery and reference sites.
Kinetics of polychlorinated biphenyl dechlorination and growth of dechlorinating microorganism
Authors: Rhee G.-Yull , Sokol Roger C , Bethoney Charlotte M , Cho Young-Cheol , Frohnhoefer Robert C , Erkkila Ted
Published: March 2010

The present study has investigated a correlation between the kinetics of polychlorinated biphenyl (PCB) dechlorination and the growth of dechlorinating microbial populations. Microorganisms were eluted from Aroclor® 1248-contaminated St. Lawrence River (NY, USA) sediments and inoculated into clean sediments spiked with Aroclor 1248 at 10 concentrations ranging from 0 to 3.12 μmol/g sediment (0–900 ppm). The time course of PCB dechlorination and population growth were concurrently determined by congener-specific analysis and the most probable number technique, respectively. The specific growth rate was a saturation function of PCB concentrations above the threshold concentration (0.14 μmol/g sediment, or 40 ppm), below which no dechlorination or growth of dechlorinations were observed. The maximum growth rate was 0.20/d with a half-saturation constant of 1.23 μmol/g sediment. The yield of dechlorinating microorganisms showed a peak at 0.70 μmol/g sediment (200 ppm), with a value of 10.3 × 1012 cells/mol Cl removed, and decreased below and above this concentration. The dechlorination rate (μmol Cl removed/g sediment/d) was a linear function of Aroclor concentration. Both the log of this rate and the maximum level of dechlorination were significantly correlated with growth rate. The biomass-normalized dechlorination rate (μmol Cl removed/g sediment/cell/d) was first order because of the exponential manner of the population growth. The first-order rate constant was a saturation function of Aroclor concentrations, with a maximum of 0.24/d (a half-life of 2.9 d) and a half-saturation constant of 1.18 μmol/g sediment, which are similar to the constants for growth. These results indicate that the dechlorination rate is tightly linked to the population growth of dechlorinating microorganisms.
Runoff simulation with particle-bound fenvalerate in multispecies stream microcosms: Importance of biological interactions
Authors: Schulz Ralf , Liess Matthias
Published: March 2010

Multispecies stream microcosms were used to test the toxicity of the pyrethroid fenvalerate (FV) associated with suspended particles in order to simulate a typical runoff exposure scenario. Stream microcosms were exposed for 1 h in triplicate to 0.0, 13.6, 136, or 1,365 μg/kg FV and effects were monitored for 93 d. Experimental design allowed for detection of interspecific effects on the emergence and thus survival of the caddisfly species Limnephilus lunatus Curtis and of intraspecific effects on the spatial distribution of adult and juvenile Gammarus pulex L. (Amphipoda). Exposure at 136- and 1,365 μg/kg resulted in a significant acute increase in drift. Survival of L. lunatus was significantly reduced in the 1,365-μg/kg treatment during single-species exposures. When other species were present, survival of L. lunatus was significantly reduced at 136 μg/kg. A similar increase in test system susceptibility was observed in relation to the spatial distribution of G. pulex. Juvenile individuals avoided areas with high numbers of adult amphipods, which may prey on the juveniles. This avoidance was significant in the control and the 13.6-μg/kg treatment but did not occur at higher levels of exposure. This study highlights the ecotoxicological importance of field-relevant levels of particle-associated hydrophobic chemicals that transiently increase during runoff events. Interspecific and intraspecific interactions can alter the test results; i.e., significant lethal and sublethal effects are measurable at FV levels approximately an order of magnitude lower than when biological interactions are excluded.
Effects of atrazine on embryos, larvae, and adults of anuran amphibians
Authors: Allran John W , Karasov William H
Published: March 2010

We examined the effects of atrazine (0–20 mg/L) on embryos, larvae, and adult anuran amphibian species in the laboratory. Atrazine treatments did not affect hatchability of embryos or 96-h posthatch mortality of larvae of Rana pipiens, Rana sylvatica, or Bufo americanus. Furthermore, atrazine had no effect on swimming speed (measured for R. pipiens only). However, there was a dose-dependent increase in deformed larvae of all three species with increasing atrazine concentration. In adult R. pipiens, atrazine increased buccal and thoracic ventilation, indicating respiratory distress. However, because atrazine had no affect on hemoglobin, this respiratory distress was probably not indicative of reduced oxygen-carrying capacity of the blood. Frogs exposed to the highest atrazine concentration stopped eating immediately after treatment began and did not eat during the 14-d experiment. However, no decreases in mass were measured even for frogs that were not eating, probably because of compensatory fluid gain from edema. Atrazine concentrations found to be deleterious to amphibian embryos and adults are considerably higher than concentrations currently found in surface waters in North America. Therefore, direct toxicity of atrazine is probably not a significant factor in recent amphibian declines.
Effects of nonylphenol, bisphenol a, and their mixture on the viviparous swordtail fish (Xiphophorus helleri)
Authors: Kwak Hyeong-Il , Bae Mi-Ok , Lee Moon-Han , Lee Yong-Soon , Lee Bum-Joon , Kang Kyung-Sun , Chae Chan-Hee , Sung Ha-Jung , Shin Jin-Sup , Kim Jin-Hwa , Mar Woong-Cheon , Sheen Yhun-Yong , Cho Myung-Haing
Published: March 2010

A number of fish species have been used for studies on endocrine disrupting chemicals (EDCs). However, despite the widespread use of oviparous fish, relatively little attention has been given to viviparous species. This study investigated the effects of EDCs in a viviparous fish and examined the possible usefulness of the fish as an alternative model for the studies on EDCs. Swordtails (Xiphophorus helleri) were exposed to nonylphenol (NP), bisphenol A (BPA), and their mixture. Both short-term (3-d) and relatively long-term (60-d) exposures were carried out using adult male and 30-d-old juvenile fish, respectively. Following the short-term exposure, both NP and BPA caused vitellogenin mRNA expression. Flow cytometric analysis and terminal deox-ynucleotidyl transferase assay on the testes of treated fish indicated reproductive damage. Histopathological analysis found degenerative and necrotic cells in seminiferous tubules following the exposure to 100 ppb NP. The testes with lesions were also associated with highly suppressed spermatogenesis. Following the long-term exposure, both NP and BPA exposures significantly affected the growth of swordtails. In all cases, the results showed that the mixture was always more potent than a single chemical and that swordtail fish can be a useful model for the study of endocrine disruptors.
Toxicity and bioaccumulation of ddt in freshwater amphipods in exposures to spiked sediments
Authors: Lotufo Guilherme R , Landrum Peter F , Gedeon Michelle L
Published: March 2010

The amphipods Hyalella azteca and Diporeia spp. were exposed to sediments dosed with dichlorodiphenyltrichloroethane (DDT), and the toxicity and toxicokinetics were determined. The toxicity was evaluated with the equilibrium partitioning (EqP) and critical body residue approaches. The DDT in the sediments degraded during the equilibration period prior to organism exposure. Thus, the toxicity using EqP pore-water toxic units (TUs) was evaluated for DDT and its degradation product, dichlorodiphenyld-ichloroethane (DDD), as the ratio of the predicted interstitial water concentration divided by the water-only LC50 values. The sum of TUs (ΣTU) was assumed to best represent the toxicity of the mixture. For H. azteca, the 10-d LC50 was 0.98 and 0.33 ΣTU for two experiments. For Diporeia spp., no toxicity was found in the first experiment with up to 3 ΣTU predicted in the interstitial water. However, in the second experiment, the 28-d LC50 was 0.67 ΣTU. These data suggest that the EqP approach approximately predicts the toxicity for the combination of DDT and DDD in sediment, provided a toxic unit approach is employed. The critical body residue approach also used TUs because DDT is biotransformed by H. azteca and because of the dual exposure to DDT and DDD. Because biotransformation was only determined in the second experiment, the critical body residue approach could only be evaluated for that case. The TUs were calculated as the ratio of the concentration in the live amphipods divided by the respective LR50 (residue concentration required to produce 50% mortality) values. The LR50 was 1.1 ΣTU for H. azteca for the 10-d exposure and 0.53 for Diporeia spp. after a 28-d exposure. Thus, this approach was also quite successful in predicting the toxicity. The accumulation and loss rates for H. azteca were much greater than for Diporeia spp. Thus, 10-d exposures represent steady-state conditions for H. azteca, while even at 28-d, the Diporeia spp. are not at steady state.
Toxicity-based criteria for the evaluation of textile wastewater treatment efficiency
Authors: Rosa Edson V. Cordova , Simionatto Edesio Luiz , de Souza Sierra Maria Marta , Bertoli Savio Leandro , Radetski Claudemir Marcos
Published: March 2010

Brazilian textile mills import wastewater treatment technologies, performances of which are generally evaluated only on a physicochemical basis. Thus, a battery of bioassays was used to evaluate the performance of an ozonation system to treat textile effluents. Comparative toxicological profiles for bacteria (Vibriofischeri), algae (Scenedesmus subspicatus), daphnia(Daphnia magna), fish (Poecilia reticulata), and plants (soybean—Glycine max, rice—Oryza sativa, and wheat—Triticum aestivum), as well as genotoxic effects (Viciafaba micronucleus assay), are presented for both raw and ozonated textile effluents. The relative sensitivity of bioassays (or end points) to textile effluents found in this study in decreasing order was plant enzymes > bacteria > algae ≈ daphnids ≈ plant biomass ≈ germination rate > fish. No significant genotoxic effect was found. We have concluded that ozonation was relatively effective in reducing toxicity of textile effluents. Bioassays used in this study proved to be sensitive and reliable tools for determining the toxicity of industrial effluents, and thus they can be used to evaluate emerging technology efficiency.