bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of perfluorooctane sulfonic acid and perfluorooctanoic acid to Chironomus tentans
Authors: MacDonald Michelle M. , Warne Amanda L. , Stock Naomi L. , Mabury Scott A. , Solomon Keith R. , Sibley Paul K. 
Published: November 2004

Abstract
Two perfluorinated surfactants, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), were evaluated for their toxicity to the aquatic midge, Chironomus tentans. Impetus for this laboratory study originated from a 10-d, in situ field assessment in which C. tentans was exposed to PFOS at concentrations ranging from 300 to 30,000 μg/L. No midges survived these exposures. Midge survival in a preliminary, acute 10-d laboratory test with nominal PFOS concentrations ranging from 0.1 to 100,000 μg/L showed similar toxicity with respect to survival (median lethal concentration [LC50], 45.2 μg/L) and growth (median effective concentration [EC50], 27.4 μg/L). A parallel test using PFOA indicated no significant impacts on survival or growth. A definitive 10-d assay with PFOS concentrations ranging from 1 to 150 μg/L produced an EC50 for growth (87.2 ± 11.6 μg/L) of the same order of magnitude as that in the preliminary findings. The same was not true for survival, however, with the LC50 falling outside the range of test concentrations. To further investigate the sensitivity of C. tentans to PFOS, we conducted a chronic life-cycle test using a nominal concentration range of 1 to 100 μg/L. Three of the four endpoints measured—survival, growth, and emergence—were significantly affected, with EC50 values of 92.2 ± 3.1, 93.8 ± 2.6, and 94.5 ± 3.2 μg/L, respectively. Reproduction was not affected by those PFOS concentrations at which females emerged. The results of the present study indicate that PFOS toxicity thresholds for C. tentans are as much as three orders of magnitude lower than those reported for other aquatic organisms but, at present, are approximately two orders of magnitude higher than those concentrations typically observed in aquatic environments.
Empirical and modeling evidence of regional atmospheric transport of current-use pesticides
Authors: Muir Derek C. G. , Teixeira Camilla , Wania Frank 
Published: November 2004

Abstract
Water samples from 30 lakes in Canada and the northeastern United States were analyzed for the occurrence of 27 current-use pesticides (CUPs). Eleven CUPs were frequently detected in lakes receiving agricultural inputs as well as in remote lakes hundreds of kilometers from known application areas. These included the triazine herbicide atrazine and its desethylated degradation product; the herbicides alachlor, metolachlor, and dacthal; the organophosphate insecticides chlorpyrifos, diazinon, and disulfoton; the organochlorine insecticides α-endosulfan and lindane; and the fungicides chlorothalonil and flutriafol. For six of the pesticides, empirical half-distances on the order of 560 to 1,820 km were estimated from the water-concentration gradient with latitude. For most of the pesticides, a suite of assessment models failed to predict such atmospheric long-range transport behavior, unless the effect of periods of lower hydroxyl radical concentrations and dry weather were taken into account. Observations and model results suggest that under the conditions prevailing in south-central Canada (relatively high latitude, low precipitation rates), many CUPs will be able to undergo regional-scale atmospheric transport and reach lakes outside areas of agricultural application. When assessing the potential of fairly reactive and water-soluble substances to undergo long-range transport, it is imperative to account for periods of no precipitation, to assure that degradation rate constants are correct, and to apply oxidant concentrations that are valid for the region and time period of interest.
Organismal effects of pesticide exposure on meadow voles (Microtus pennsylvanicus) Living in golf course ecosystems: Developmental instability, clinical hematology, body condition, and blood parasitology
Authors: Knopper Loren D. , Mineau Pierre 
Published: November 2004

Abstract
This is the second of two articles reporting the results of a nonlethal biomonitoring study that quantified the effects of pesticide exposure on meadow voles (Microtus pennsylvanicus) living in golf course ecosystems of the Ottawa/Gatineau region (ON and PQ, Canada, respectively). In the present article, we describe results of measurements regarding developmental instability (e.g., fluctuating asymmetry), congenital birth defects (e.g., skeletal terata), clinical hematology (e.g., differential counts), general body condition (e.g., body mass-length relationships), and blood parasite load (Trypanosoma sp. and Bartonella spp.). Voles were captured during the year 2001 to 2003 at six golf courses and two reference sites. Once voles were fully sedated using isoflurane, blood was collected, radiographs taken, and morphometric measurements recorded. Three animals from each course were euthanized to determine body burdens of historically used organochlorine (OC) and metal-based pesticides. Exposure to in-use pesticides was determined from detailed golf course pesticide-use records. None of the endpoints measured was significantly related to body burdens of OC pesticides and metals historically used, nor did any endpoint significantly vary among capture sites in relation to total pesticide application to the capture site or to the number of days since the last application of pesticide. Based on these findings, it appears that voles from golf courses were no less healthy than their conspecifics from reference sites.
Dietary accumulation and metabolism of polybrominated diphenyl ethers by juvenile carp (Cyprinus carpio)
Authors: Stapleton Heather M. , Letcher Robert J. , Li Juliana , Baker Joel E. 
Published: November 2004

Abstract
Polybrominated diphenyl ethers (PBDEs) are hydrophobic organic contaminants with properties and nomenclature similar to polychlorinated biphenyls (PCBs). While much information is available on the bioaccumulation and pharamcokinetics of PCBs, little information is available on PBDEs. In this study, juvenile carp were exposed to a diet spiked with a cocktail of four BDE congeners (2,4,4′-tribromoDE [BDE 28], 2,2′,4,4′-tetrabromoDE [BDE 47], 2,2′,4,4′,5-pentabromoDE [BDE 99], and 2,2′,4,4′,5,5′-hexabromoDE [BDE 153]) for 60 d followed by a 40-d depuration period. As a positive control, three PCB congeners with similar log Kow values (2,2′,5,5′-tetrachlorobiphenyl [PCB 52], 2,2′,4,4′, 5,5′-hexachlorobiphenyl [PCB 153], and 2,2′,3,4,4′,5,5′-heptachlorobiphenyl [PCB 180]) were included in the cocktail to compare their assimilation and fate with the model BDE congeners. Concentrations of BDEs and PCBs were monitored in whole-fish tissues and liver tissues over the duration of the experiment. In addition, blood serum samples were taken and pooled among replicates to determine if any phenolic metabolites of BDE and PCBs were formed. Rapid assimilation of BDE 47 was observed relative to all other BDE and PCB congeners, whereas apparently no accumulation of BDE 99 occurred over the course of the experiment. Assimilation efficiencies for BDE 47 suggest that approximately 100% of the BDE 47 exposure was absorbed by carp tissues after 60 d. However, based on the time course of BDE 47 assimilation, it is improbable that all BDE 47 was assimilated; more likely, production of BDE 47 in carp tissues occurred as a result of debromination of higher-brominated compounds, possibly BDE 99. The net assimilation efficiencies of BDE 28 and BDE 153 were also apparently low (20 and 4%, respectively) relative to the three PCBs (40% assimilated) examined in this study. The low assimilation efficiency and high depuration rates for BDEs suggest a higher potential for biotransformation. While all three PCB compounds displayed very similar assimilation and depuration rates, three of the four BDE compounds displayed significantly different assimilation rates among BDE congeners and relative to the PCBs. This study suggests that BDEs have significantly different fate dynamics relative to PCBs in wild carp and likely other species of fish.
Finding fugacity feasible, fruitful, and fun
Authors: MacKay Don 
Published: November 2004

Abstract
A review is presented concerning the evolution of the fugacity concept as applied to environmental science. The series of serendipitous events that ultimately resulted in publication of the paper “Finding Fugacity Feasible” in 1979 is described. The use of fugacity as a surrogate for concentration is shown to facilitate the compilation and solution of mass-balance equations. It has proved to be valuable in a number of contexts, notably the description of chemical fate in unit worlds at various levels of complexity. More complex systems can be simulated as sets of connected unit worlds. The fugacity approach enables the multimedia character of organic chemicals to be deduced, thus contributing to the evaluation of chemical properties that impact persistence and long-range transport. It has proved to be especially insightful for describing bioconcentration, bioaccumulation, and pharmacokinetic phenomena. Applications to the sensing and monitoring of chemical presence in the environment are described. Suggestions are made for subject areas in which the fugacity concept may prove to be particularly valuable in the future. Finally, the many colleagues who have contributed to the use of fugacity when quantifying chemical behavior in the environment are acknowledged.
Destabilized lysosomes and elimination of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in eastern oysters (Crassostrea virginica)
Authors: Hwang Hyun-Min , Wade Terry L. , Sericano Jose L. 
Published: November 2004

Abstract
Contaminated oysters from near the Galveston Bay Ship Channel ([GBSC], TX, USA) were transplanted into clean aquariums in order to investigate the recovery of their lysosomal health. Destabilized lysosomes in the oyster hemocytes recovered from 81% to 34% after 23 d of elimination. Chemical analyses showed that transplanted oysters eliminated organic chemicals they had accumulated in their tissue. Enhanced lysosomal health (i.e., decreased lysosomal destabilization) was correlated positively with lower tissue concentrations of chemicals. This study indicates that lysosomal destabilization is a transient biomarker, which indicates only the current status (e.g., within one month) of chemical exposure and potential adverse biological effects. Analytical measurements revealed that polycyclic aromatic hydrocarbons (PAHs) generally were eliminated faster than polychlorinated biphenyls (PCBs) by a factor of 5 to 7. Body burdens of PCBs decreased exponentially, while the elimination pattern of PAHs were biphasic, representing a faster elimination during the early phase of elimination and, subsequently, a much slower elimination. This indicates that elimination of PAHs in the oysters is more complex and may include additional mechanisms compared to the uptake and elimination of PCBs.
Effects of a rhamnolipid biosurfactant on the reductive dechlorination of polychlorinated biphenyls by St. Lawrence River (North America) microorganisms
Authors: Cho Young-Cheol , Ostrofsky Ellen B. , Rhee G.-Yull 
Published: November 2004

Abstract
The effect of a rhamnolipid biosurfactant on the reductive dechlorination of polychlorinated biphenyls was investigated with the use of clean sediments spiked with Aroclor 1248. The surfactant was added to the contaminated sediments at four different concentrations (5, 10, 25, and 50 μg/g sediment [ppm] on a sediment dry wt basis), and dechlorination was followed over a 40-week period. The rate of overall dechlorination was enhanced at the three highest concentrations. Dechlorination at the lowest concentration (5 ppm) was not different from that in surfactant-free sediments. On a congener basis, enhanced dechlorination was mostly found in the congeners that have high threshold concentrations for dechlorination. These congeners are characterized by an initial increase in concentration before dechlorination starts. At the three highest biosurfactant concentrations, this initial concentration increase was absent or dramatically reduced. Therefore, the enhancement in dechlorination appears to be caused by an increase in bioavailability at high surfactant concentrations. The biosurfactant also reduced the lag time before dechlorination began in these congeners. Among those congeners that have low threshold concentrations, dechlorination enhancement was found only in two peaks. For these two, there was no lag period, either with or without the rhamnolipids. The maximum level of dechlorination and the congener pattern of final dechlorination products were identical, regardless of biosurfactant concentration.
The role of desorption for describing the bioavailability of select polycyclic aromatic hydrocarbon and polychlorinated biphenyl congeners for seven laboratory-spiked sediments
Authors: Kukkonen Jussi V. K. , Landrum Peter F. , Mitra Siddhartha , Gossiaux Duane C. , Gunnarsson Jonas , Weston Donald 
Published: November 2004

Abstract
Lumbriculus variegatus and Diporeia spp. were exposed to two contaminant pairs 3H-benzo[a]pyrene (BaP) and 14C-2,4,5,2′4′,5′-hexachlorobiphenyl (HCBP), and 3H-pyrene (PY) and 14C-3,4,3′,4′-tetrachlorobiphenyl (TCBP) sorbed to each of seven field-collected sediments of varying composition. Toxicokinetic coefficients, bioaccumulation factors (BAF), and biota-sediment accumulation factors ([BSAF], BAF normalized to the organism lipid content and sediment organic carbon content) were determined. The contaminant desorption rates from sediments were measured with a Tenax resin extraction technique. The desorption rate constants for rapid, slow, and very slow contaminant compartments and the fractions of contaminant in each compartment were compared with the toxicokinetic coefficients, BAF, and BSAF to describe contaminant behavior across sediments, among compounds, and between species. The best description of the bioavailability was the log BSAF regressed against the fraction rapidly desorbed (Frapid) across all sediments and compounds for both species, r2 = 0.67 and 0.66 for L. variegatus and Diporeia, respectively. Use of a calculated fraction desorbed in 6 h or 24 h, which has been suggested as a surrogate for Frapid, did not produce as predictive a regression because of uneven desorption in a fixed duration for each compound among the sediments. Thus, Frapid provided a good surrogate for the bioavailability of the sediment-sorbed contaminant as represented by BSAF across seven sediments and four compounds with predictions within a factor of approximately two of the measured value.
Comparison of two screening bioassays, based on the frog sciatic nerve and yeast cells, for the assessment of herbicide toxicity
Authors: Papaefthimiou Chrisovalantis , de Guadalupe Cabral Maria , Mixailidou Christina , Viegas Cristina A. , Sá-Correia Isabel , Theophilidis George 
Published: November 2004

Abstract
Two different tests systems, one based on the isolated sciatic nerve of an amphibian and the other on a microbial eukaryote, were used for the assessment of herbicide toxicity. More specifically, we determined the deleterious effects of increasing concentrations of herbicides of different chemical classes (phenoxyacetic acids, triazines, and acetamides), and of 2,4-dichlorophenol (2,4-DCP), a degradation product of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), on electrophysiological parameters and the vitality of the axons of the isolated sciatic nerve of the frog (Rana ridibunda) and on the growth curve of the yeast Saccharomyces cerevisiae based on microtiter plate susceptibility assays. The no-observed-effect-concentration (NOEC), defined as the maximum concentration of the tested compound that has no effect on these biological parameters, was estimated. In spite of the different methodological approaches and biological systems compared, the NOEC values were identical and correlated with the lipophilicity of the tested compounds. The relative toxicity established here, 2,4-DCP &gt; alachlor, metolachlor ≫ metribuzin &gt; 2,4-D, 2-methyl-4-chlorophenoxyacetic acid (MCPA), correlates with the toxicity indexes reported in the literature for freshwater organisms. Based on these results, we suggest that the relatively simple, rapid, and low-cost test systems examined here may be of interest as alternative or complementary tests for toxicological assessment of herbicides.
Growth and survival of five amphibian species exposed to combinations of pesticides
Authors: Relyea Rick A. 
Published: November 2004

Abstract
The global decline of amphibians has sparked interest in the role that pesticides may play. Pesticides in nature typically exist in combinations, but given the vast number of chemicals used, most toxicological experiments necessarily have examined one pesticide at a time. I examined how four commercial formulations of pesticides (diazinon, carbaryl, malathion, and glyphosate) affected the survival and growth of five larval amphibian species (Rana pipiens, R. clamitans, R. catesbeiana, Bufo americanus, and Hyla versicolor) when alone (at 1 or 2 mg/L of active ingredient) and in pairwise combinations (1 mg/L of each pesticide). At 1 mg/L, the pesticides reduced survival in 5% of the 20 species–pesticide comparisons and reduced growth in 35% of the comparisons. At 2 mg/L, the pesticides had more widespread effects, reducing survival in 35% of the 20 species–pesticide comparisons and reducing growth in 70% of comparisons. Combined pesticides occasionally caused lower survival and growth than either pesticide alone, but the effects were never larger than the more deadly of the two pesticides alone at 2 mg/L. This suggests that the impact of combining these four pesticides is similar to that predicted by the total concentration of pesticides in the system.
Utility of morphological abnormalities during early-life development of the estuarine mummichog, Fundulus heteroclitus, as an indicator of estrogenic and antiestrogenic endocrine disruption
Authors: Boudreau Monica , Courtenay Simon C , Maclatchy Deborah L. , Bérubé Céline H. , Parrott Joanne L. , van der Kraak Glen J. 
Published: November 2004

Abstract
To evaluate the use of morphological abnormalities for standard testing of endocrine-disrupting substances (EDS), we tested the hypothesis that developmental abnormalities are a sensitive indicator of exposure to waterborne estrogenic and antiestrogenic EDS during embryonic, larval, and juvenile stages in the common estuarine killifish, the mummichog (Pisces: Cyprino-dontidae). Static exposures with daily renewal were carried out with 10 to 10,000 ng/L of the estrogen agonist 17α-ethynylestradiol (EE2) or antagonist ZM189,154 (ZM) for the first 25 or 60 d of life. Incidence of skeletal abnormalities (scoliosis, lordosis, head, craniofacial, jaw, fin) and soft tissue abnormality (anal swelling) were significantly increased by EE2 but only at high concentrations (1,000 or 10,000 ng/L). Sixty-day exposure produced more severe abnormalities than 25-d exposure and in a higher proportion of fish. Within the longer exposure, 10,000 ng/L EE2 produced more abnormal fish than 1,000 ng/L (100% vs 51.6%) and more abnormalities per abnormal fish (5.73 vs 1.47). Fish reared to 12 months in clean water after exposure for 60 d to 10,000 ng/L EE2 survived at a lower rate than controls, retained abnormalities with the exception of anal swelling and, like fish exposed to other concentrations of EE2 and ZM, showed increased weight at length at 6 and 12 months. Sixty-day exposure to ZM increased the incidence of scoliosis (1,000 ng/L) but decreased the overall incidences of abnormal fish and lordosis (10 and 10,000 ng/L). No impacts of EE2 or ZM were observed before hatch, and clearing and staining of larvae demonstrated that expression of vertebral abnormalities coincided temporally with ossification. We conclude that morphological abnormalities in mummichogs are not a sensitive indicator of exposure to estrogenic or antiestrogenic waterborne EDSs at environmentally relevant concentrations.
Dietary assimilation and elimination of Cd, Se, and Zn by Daphnia magna at different metal concentrations
Authors: Guan Rui , Wang Wen-Xiong 
Published: November 2004

Abstract
This study examines the influences of Cd, Se, and Zn concentrations in ambient water on the assimilation, elimination, and release budget of metals, and the clearance rate of Daphnia magna through ingestion of phytoplankton diets. With increasing ambient metal concentration over two to three orders of magnitude, the assimilation efficiencies (AEs) of Cd and Se from two green algal species, Scenedesmus obliquus and Chlamydomonas reinhardtii, decreased significantly. In contrast, the Zn AE from ingested food, which typically was low (&lt;7%), was not impacted by the difference in Zn or Cd concentrations in ingested cells. The Cd AE also was reduced significantly by a high Zn concentration in ingested algae, perhaps due to the competitive assimilation between the two metals. Metal elimination was determined after the daphnids were exposed to the radiolabeled diets for 3 d. The elimination rate constant was not dependent on the metal concentration in ingested food. Similarly, the routes of metal elimination (excretion, egestion, molting, and neonate production) were less influenced by the metal concentration. The rapid elimination of Se and Zn may be attributed to the transfer of these metals from mother to offspring. Except at the highest Cd (917 nM) and Se (1,333 nM) concentrations, there was no significant effect of metal concentration on the clearance rate of the animals. Consequently, the metal assimilation in D. magna may play an important role in the regulation of Cd and Se influx into the animals, whereas the regulation of the metal tissue burden in the animals is unlikely to be achieved through the metal elimination. The trophic transfer factors (TTF) of Cd and Se were related inversely to the metal concentration in the water, whereas the TTF of Zn was less variable at different Zn concentrations. The change of TTF with metal concentration will have important implication for ecotoxicity testing using D. magna, especially when the dietary exposure is incorporated.
Using artificial streams to assess the effects of metal-mining effluent on the life cycle of the freshwater midge (Chironomus tentans) in situ
Authors: Hruska Kimberly A. , Dubé Monique G. 
Published: November 2004

Abstract
In 2002, we developed an in situ life-cycle bioassay with Chironomus tentans in artificial streams to evaluate the effects of a complex metal mine effluent under ambient environmental conditions. The bioassay was tested in the field using effluent from the Copper Cliff Waste Water Treatment Plant at INCO (Sudbury, ON, Canada). Chironomus tentans were exposed throughout the life cycle to 45% Copper Cliff effluent, which is the average effluent concentration measured in Junction Creek (ON, Canada), the natural receiving environment. Chironomus tentans in the effluent treatment exhibited reduced survival (p = 0.001), reduced total emergence (p = 0.001), increased time-to-emergence (p = 0.001), and reduced hatching success (p = 0.001) relative to animals in the reference water treatment. Chironomus tentans in the effluent treatment were not significantly different from the reference in terms of growth, sex ratio, number of egg cases/female, and number of eggs/egg case. This research showed how a life-cycle bioassay could be used in situ to assess metal mine effluent effects on a benthic invertebrate.