bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the oral bioavailability of methylmercury to channel catfish (Ictalurus punctatus)
Authors: McCloskey John T , Schultz Irvin R , Newman Michael C 
Published: March 2010

Abstract
In classical pharmacology, oral bioavailability of a toxicant is defined as that fraction of an orally administered dose reaching the systemic circulation of the animal. The present study estimates the bioavailability of methylmercury in channel catfish (Ictalurus punctatus) by comparing concentrations in the blood through time after oral and intra-arterial (IA) administration. Catfish were cannulated in the dorsal aorta and gavaged a pelleted feed that had been spiked with methylmercury. Each catfish was gavaged an increasing amount of spiked feed. Following oral dosing, serial blood samples were removed for more than 1,500 h. One month after removal of the last blood sample, the same fish were injected IA with methylmercury and serial blood samples were removed for more than 3,000 h. The area under the curve of the blood concentration-time curve extrapolated to infinity (AUC0→∞) was calculated from fish dosed orally and IA using both noncompartmental (trapezoidal) and compartmental methods. Bioavailability was estimated as the ratio of the dose-corrected oral AUC0→∞ to the IA AUC0→∞. Average bioavailability estimates from this approach were 33% using noncompartmental (range 14–55%) and 29% using compartmental (range 12–42%) methods and were correlated with the amount of food gavaged to the fish (r2 = 0.95, p = 0.026). Bioavailability estimates using the present methods were much lower than estimates using more conventional methods (i.e., assimilation efficiency estimates using mass balance), suggesting that conventional methods may overestimate the true bioavailability of toxicants in fish.
Assessment of sediment toxicity and chemical concentrations in the San Diego Bay region, California, USA
Authors: Fairey Russell , Roberts Cassandra , Jacobi Michele , Lamerdin Stewart , Clark Ross , Downing James , Long Edward , Hunt John , Anderson Brian , Newman John , Tjeerdema Ronald , Stephenson Mark , Wilson Craig 
Published: March 2010

Abstract
Sediment quality within San Diego Bay, Mission Bay, and the Tijuana River Estuary of California was investigated as part of an ongoing statewide monitoring effort (Bay Protection and Toxic Cleanup Program). Study objectives were to determine the incidence, spatial patterns, and spatial extent of toxicity in sediments and porewater; the concentration and distribution of potentially toxic anthropogenic chemicals; and the relationships between toxicity and chemical concentrations. Rhepoxynius abronius survival bioassays, grain size, and total organic carbon analyses were performed on 350 sediment samples. Strongylocentrotus purpuratus development bioassays were performed on 164 pore-water samples. Toxicity was demonstrated throughout the San Diego Bay region, with increased incidence and concordance occurring in areas of industrial and shipping activity. Trace metal and trace synthetic organic analyses were performed on 229 samples. Copper, zinc, mercury, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlordane were found to exceed ERM (effects range median) or PEL (probable effects level) sediment quality guidelines and were considered the six major chemicals or chemical groups of concern. Statistical analysis of the relationships between amphipod toxicity, bulk phase sediment chemistry, and physical parameters demonstrated few significant linear relationships. Significant differences in chemical levels were found between toxic and nontoxic responses using multivariate and univariate statistics. Potential sources of anthropogenic chemicals were discussed.
Toxicity of endosulfan to aquatic stages of anuran amphibians
Authors: Berrill Michael , Coulson Donna , McGillivray Lise , Pauli Bruce 
Published: March 2010

Abstract
The toxicity of endosulfan insecticide to wood frog (Rana sylvatica) embryos and tadpoles of wood frogs, American toads (Bufo americanus), and green frogs (R. clamitans) was examined in the laboratory. Following exposures to 0.03 to 0.4 mg/L endosulfan for 96 h, sublethal effects and postexposure mortality were assessed. In another experiment, premetamorphic American toad tadpoles (with developing hindlimbs but unerupted front legs) were exposed to 0.3 mg/L endosulfan for 96 h. The exposed wood frog embryos hatched successfully and were morphologically indistinguishable from the unexposed animals at the end of the 10-d postexposure period. However, extensive paralysis of exposed tadpoles of all three species occurred; all but one of the exposures resulted in 100% of the tadpoles experiencing paralysis at some point during the exposure or recovery period. Postexposure mortality of tadpoles was high and occurred at the lowest exposure concentrations (0.041–0.053 mg/L) for each species exposed as 2-week-old tadpoles. Newly hatched American toad tadpoles were more tolerant than tadpoles of the other two species, but no clear species differences in sensitivity of 2-week-old tadpoles was apparent. American toad premetamorphs exposed to endosulfan did not recover from the effects of the exposure. Our results indicate that the aquatic stages of anuran amphibians may be sensitive to levels of the pesticide endosulfan that could reach their habitat by means of direct applications or drift from aerial spraying.
Lethal effects of Mexel® 432 to common carp embryolarval stages in river water: Influence of physicochemical parameters in synthetic ISO water
Authors: Arehmouch Latifa , Tfibel Valérie , Chaillou Catherine , Ghillebaert François , Roubaud Pierre 
Published: March 2010

Abstract
The lethal effects of Mexel® 432, an antifouling agent for industrial water circuits, on common carp embryolarval stages in Moselle and Seine River waters and synthetic water were tested in the laboratory. Diluting Mexel 432 in river water resulted in the disappearance of its lethal effects within a few days. In freshly prepared 3-mg/L solutions, 100% mortality occurred within 1 d in synthetic International Standards Organization (ISO) water, compared to 96 h in Seine River water (10-mg/L solutions). No lethal effect was observed after 7 d of exposure in an 8- to 15-d-old 50-mg/L solution in Moselle River water or in a 2-d-old 10-mg/L solution in Seine River water. Inhibition of Mexel 432 toxicity by river waters was not due to calcium concentration, temperature, or pH, because these factors had a negligible influence on the lethal effects of Mexel 432 in synthetic ISO water (ranges, 0.8–800 mg/L, 15–24°C, and 6.9–9.0, respectively). Aldrich Chemical humic acids immediately suppressed the lethal effects of Mexel 432 with an apparent ratio of 1 to 2 mg Mexel 432/mg humic acids. Also, clays and humic acids immediately reduced the concentration of Mexel 432 in semiquantitative colorimetric dosages.
Reproduction and environmental contamination in tree swallows nesting in the Fox River Drainage and Green Bay, Wisconsin, USA
Authors: Custer Christine M , Custer Thomas W , Allen P David , Stromborg Kenneth L , Melancon Mark J 
Published: March 2010

Abstract
Concentration, accumulation, and effects of polychlorinated biphenyls (PCBs) o nreproduction in tree swallows (Tachycineta bicolor) were studied at four sites in the Fox River drainage and in Green Bay, Lake Michigan, Wisconsin, USA, in 1994 and 1995. Total PCBs in eggs and newly hatched young (mean = 3.01 μg/g wet weight, years and sites combined) and 12-d-old nestlings (mean = 2.34 μg/g wet weight) at two contaminated sites (Kidney Island and Arrowhead) were higher than concentrations at two reference sites (Lake Poygan and High Cliff State Park, years and sites combined, pippers mean = 0.26 μg/g, nestlings mean = 0.01 μg/g). Concentrations of 11 PCB congeners were also higher at contaminated compared to reference sites. Polychlorinated biphenyls (PCBs) accumulated in nestlings at a higher rate (1.34–6.69 μg/d) at contaminated sites compared to reference locations (0.06–0.42 μg/d). Dichlorodiphenyldichloroethylene (DDE) was the only other organochlorine found in all samples; concentrations for all samples averaged ≤0.20 μg/g wet weight. Total PCBs and p,p′-DDE concentrations did not differ among clutches where all eggs hatched, some eggs hatched, and no eggs hatched.
Assessment of surface water quality on three eastern North Carolina golf courses
Authors: Ryals Scott C , Genter Mary Beth , Leidy Ross B 
Published: March 2010

Abstract
The golf course industry has become increasingly aware of potential problems related to pesticide and fertilizer movement from soil into surface water and groundwater. Recently, the industry has started to change application practices and pesticide formulations and to participate in routine monitoring studies. Three southeastern North Carolina golf courses agreed to participate in a surface water quality study to determine the movement of fertilizers and related pesticides into surface waters. All three golf courses have ponds that provide irrigation water, from which samples were collected every two weeks. Each course has a sandy loam soil and adjoins wetlands, saline marshes, or elevated water tables. The data indicate that impact to the surface waters from the courses was minimal. Of the four pesticides (atrazine, chlorothalonil [Daconil®], chlorpyrifos [Dursban®], and 2,4-dichlorophenoxyacetic acid) and two nutrients (nitrogen and phosphate) surveyed, only 16 samples exceeded the U.S. Environmental Protection Agency's health advisory levels. All analyses of the samples collected from the outflows of the courses were below their detectable levels.
Solid-phase test for comparison of degradation rates of synthetic mud base fluids used in the off-shore drilling industry
Authors: Munro Pauline D , Croce Bronwen , Moffat Colin F , Brown Nigel A , McIntosh Alistair D , Hird Simon J , Stagg Ronald M 
Published: March 2010

Abstract
A solid-phase degradation test has been developed to assess the fate in marine sediment of synthetic mud base fluids used in the off-shore drilling industry. The degradation rate of an ester-type drilling fluid was investigated at three nominal concentrations in a fine sand. A naturally occurring triester, olive oil, was used as a positive control and a traditional mineral oil served as an example of a poorly degradable substance. Two synthetic drilling fluids, an ester and a blend of n-alkanes with poly-alpha olefin and linear-alpha olefin, were compared in a mud and a coarse sand to examine the effect of different sediments on degradability. Glass jars, containing marine sediment that had been homogeneously mixed with test fluid, were placed in troughs in a continuous flow of seawater. Periodically, triplicate jars were sacrificed and, following solvent extraction, the concentration of test fluid remaining in the sediment was determined by gas chromatography with flame ionization detection. The test was able to reproducibly distinguish between easily degradable and poorly degradable fluids. The rate of degradation was concentration dependent; the half-life increased as the nominal concentration increased. The ester was more rapidly degraded than the blended synthetic drilling fluid and degradation was slower in sand compared with mud.
Effects of a copper-tolerant grass (Agrostis capillaris) on the ecosystem of a copper-contaminated arable soil
Authors: Boon Gerben T , Bouwman Lucas A , Bloem Jaap , Römkens Paul F.A.M 
Published: March 2010

AbstractTo test how a dysfunctioning ecosystem of a severely metal-polluted soil responds to renewed plant growth, a pot experiment was conducted with soil from an experimental arable field with pH and copper gradients imposed 13 years ago. In this experiment, four pH/copper combinations from this field were either planted with a pH- and copper-resistant grass cultivar or remained fallow. During a 10-week period, the dynamics of the microbial activity and of the abundances of bacteria, protozoa, and nematodes were measured, as were the dynamics of several chemical soil parameters. After 13 years of copper (750 kg copper per hectare) and/or pH stress (6.1® 4.7), which had resulted in severely reduced crop growth, no effects were observed on bacterial numbers, respiration, or protozoan numbers, but bacterial growth (measured as [3H]thymidine incorporation into bacterial DNA) was strongly reduced in the low pH plots, and even more so in low pH plots enriched with copper. Of the organisms, only nematodes were negatively affected under conditions of high copper load at low pH. In these plots, numbers belonging to all feeding categories were strongly reduced. Planting of a copper-tolerant grass variety, Agrostis capillaris L. var. Parys Mountain, resulted within 10 weeks in faster bacterial growth and more protozoa and bacterivorous nematodes in comparison with fallow controls; these effects were markedly strongest in the acidic, copper-enriched soils. During incubation, fungivorous nematodes increased in all treatments, in fallow and in planted pots and in the pots with high-copper, low-pH soil. The results of this experiment suggest that introduction of plant growth is one of the major causes of increased biological activity in acidic contaminated soils (approximately 1.2 times the current EC limits). Planting such soils with metal-tolerant plant species can reestablish the necessary food base to support soil organism growth, and this can lead to numerous positive effects, reversing the loss of soil functions due to the high copper levels under acidic conditions.
Using a triad approach in the assessment of hazardous waste site leaching from a superfund site to an adjacent stream
Authors: Leppanen Christy J , Blanner Pat M , Allan Roger S , Benson William H , Maier Kurt J 
Published: March 2010

Abstract
A triad approach was used in the evaluation of sediment in the Wolf River adjacent to the North Hollywood Dump, a federally listed superfund site. Chemical analyses were done for 18 organochlorine pesticides, 21 polychlorinated biphenyl (PCB) congeners, and 10 metals. Sediment toxicity was evaluated with freshwater invertebrates, Chironomus tentans and Hyalella azteca. Benthic macroinvertebrate diversity and abundance were assessed with a family-level biotic index. Mean Al, Ba, Cd, Cu, Fe, Ni, Pb, and Zn concentrations were significantly higher in sediments collected in the spring. Both spring and fall sediments exhibited toxicity downstream from, adjacent to, and upstream from the dump, with toxicity significantly higher in fall sediments; however, a consistent trend was not observed. Toxicity was typically greater in the fall, and metal concentrations were typically higher in spring sediments, suggesting that metals were not responsible for the toxicity. Sediment-associated organochlorine pesticide and PCB congener concentrations were all below detectable limits, suggesting that these potential contaminants are not contributing to the observed toxicity. No differences were found in benthic macroinvertebrate community structure, which was composed of predominantly pollution-tolerant families, among seasons or river reaches, which appear to be limited by the physical characteristics of the river (e.g., substrate instability, low total organic carbon (&lt;0.6%), and water velocity). Sediments in urban reaches of the Wolf River appear to be degraded; the North Hollywood Dump cannot be isolated as a source of toxicity in this study. In situ testing, sediment toxicity identification and evaluation testing, acid-volatile sulfide analyses, or artificial substrate work would be appropriate to follow.
Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams
Authors: Hickey Christopher W , Clements William H 
Published: March 2010

Abstract
We performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communities in New Zealand streams were similar to those reported for metal-polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal-polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, we recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.
Effects of ultraviolet light and methoprene on survival and development of Rana pipiens
Authors: Ankley Gerald T , Tietge Joseph E , DeFoe David L , Jensen Kathleen M , Holcombe Gary W , Durhan Elizabeth J , Diamond Stephen A 
Published: March 2010

Abstract
Recently a suite of relatively specific hindlimb deformities have been observed in several anuran species in North America. These deformities include ectopic and supernumerary limbs and missing limbs, limb segments, or digits. The objective of this study was to assess two stressors hypothesized as responsible for limb malformations in amphibians: methoprene, an insect growth regulator that, through interaction with the retinoic acid signaling system, could possibly cause limb deformities, and ultraviolet (UV) light. Northern leopard frogs (Rana pipiens) were exposed to several different concentrations of methoprene both in the absence and presence of UV light designed to mimic the UV wavelength spectrum present in sunlight. Exposures were initiated at early embryonic stages (newly fertilized eggs) and continued through emergence of the forelimbs of the frogs. At the highest methoprene concentration tested, both in the absence and presence of UV light, severe developmental effects were observed, with all organisms dying within 12 to 16 d of test initiation. However, exposure to the pesticide did not cause limb malformations. Irrespective of methoprene treatment, a very high percentage (∼50%) of animals held under the UV light for 24 d developed hindlimb malformations. These malformations usually were bilateral and sometimes completely symmetrical, and consisted of missing limb segments and missing or reduced digits. A complete proximal to distal representation of the deficiencies occurred, ranging from missing or malformed femurs to the absence of single digits or digit segments. The developmental period of greatest sensitivity to UV light occurred during very early limb bud development, corresponding with formation of the apical ectodermal ridge. The significance of these findings in terms of deformed frogs in the field is uncertain. Although the deformity types observed (i.e., missing limb segments and digits) were similar to those seen in some field specimens, the UV light treatment did not cause the full range of malformations observed in animals from the field (e.g., supernumerary limbs, nonbilateral deformities). Furthermore, although the artificial light spectrum utilized mimicked the relative UV spectrum present in sunlight, it did not match full sunlight intensity, and did not accurately mimic visible wavelengths. Finally, the relationship of the UV light dose used in the laboratory to that actually experienced by amphibians in the field is uncertain. Despite these questions, our findings suggest that UV light should be further considered as a plausible factor contributing to amphibian malformations in field settings.
Traditional multivariate techniques: Potential for use in ecotoxicology
Authors: Sparks Tim H , Scott W Andy , Clarke Ralph T 
Published: March 2010

Abstract
This paper summarizes established multivariate techniques and illustrates examples of their use with ecotoxicological data. Multivariate analysis can be broken down into three main areas of application: ordination, clustering/discrimination, and investigating relationships between sets of variables. Many of these techniques are well established, having been developed in the first half of this century. Although some multivariate techniques predate the very familiar analysis of variance (ANOVA), the popularity of multivariate analysis in ecotoxicology is currently overshadowed by ANOVA and regression techniques. We suggest that this will become increasingly less the case and that we can expect to see much greater use of multivariate techniques in ecotoxicology in the future.
Parental exposure to ortho, para-dichlorodiphenyltrichloroethane impairs survival skills of atlantic croaker (Micropogonias undulatus) larvae
Authors: Faulk Cynthia K , Fuiman Lee A , Thomas Peter 
Published: March 2010

Abstract
Three behavioral assays were used to investigate the effect of parental exposure to ortho, para-dichlorodiphenyltrichloroethane (o, p′-DDT, 2.0 or 10.0 μg per 100 g fish per day in the diet for 1 month) on the behavior of Atlantic croaker, Micropogonias undulatus, larvae. Responses to separate visual and vibratory stimuli, as well as routine swimming activity, were quantified using motion analysis equipment. Eggs collected immediately after spawning from adults administered the 2.0 and 10.0 μg per 100 g fish per day doses of DDT contained 0.016 ± 0.002 and 0.049 ± 0.002 μg DDT per egg, respectively. Of the behavioral variables examined, proportion of larvae responding to a vibratory stimulus, burst and routine swimming speeds, active duration, and pause duration were most affected by parental exposure to o, p′-DDT. Mean and maximum burst speeds in response to the visual stimulus were higher for control larvae. The proportion of larvae responding to the vibratory stimulus was significantly higher for control larvae only after yolk and oil globule absorption. Effects of DDT exposure on routine swimming activity were only observed prior to complete oil globule absorption. Changes in these variables due to parental exposure may decrease a fish's chance of survival by increasing predation rates and/or decreasing feeding rates.