bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of sedimentary cadmium on the behavior of a burrowing mayfly (Ephemeroptera, Hexagenia limbata)
Authors: Gosselin Anne , Hare Landis 
Published: November 2004

Abstract
Behavioral responses of aquatic invertebrates can serve as precocious indicators of adverse effects caused by metals. We conducted experiments to determine if the behavior of nymphs of the burrowing mayfly Hexagenia limbata (Ephemeroptera) was modified by the presence of cadmium (Cd) in sediments. We first exposed H. limbata to concentrations of sedimentary Cd found in lakes subject to smelter emissions (20 μg/g dry wt). We then compared the burrowing activity of control and Cd-contaminated nymphs by means of radiographs. We also studied the time allotted by nymphs to various activities (irrigation, walking, burrowing/ feeding, cleaning, and turning) as determined from films taken using an infrared video camera. The results obtained suggest no significant difference in the burrowing activity of control versus Cd-contaminated individuals. Furthermore, the time spent in various behavioral activities was similar between control and Cd-contaminated nymphs. Given these results, we conclude that Cd has no effect on the behavior of H. limbata for the range of Cd concentrations that we measured in nymphs.
Blarina brevicauda as a biological monitor of polychlorinated biphenyls: Evaluation of hepatic cytochrome P450 induction
Authors: Russell Julie S. , Halbrook Richard S. , Woolf Alan , French John B. , Melancon Mark J. 
Published: November 2004

Abstract
We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with β-naphthoflavone (βNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received βNF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal.
Mysid crustaceans as potential test organisms for the evaluation of environmental endocrine disruption: A review
Authors: Verslycke Tim A. , Fockedey Nancy , McKenney Charles L. , Roast Stephen D. , Jones Malcolm B. , Mees Jan , Janssen Colin R. 
Published: November 2004

Abstract
Anthropogenic chemicals that disrupt the hormonal systems (endocrine disruptors) of wildlife species recently have become a widely investigated and politically charged issue. Invertebrates account for roughly 95% of all animals, yet surprisingly little effort has been made to understand their value in signaling potential environmental endocrine disruption. This omission largely can be attributed to the high diversity of invertebrates and the shortage of fundamental knowledge of their endocrine systems. Insects and crustaceans are exceptions and, as such, appear to be excellent candidates for evaluating the environmental consequences of chemically induced endocrine disruption. Mysid shrimp (Crustacea: Mysidacea) may serve as a viable surrogate for many crustaceans and have been put forward as suitable test organisms for the evaluation of endocrine disruption by several researchers and regulatory bodies (e.g., the U.S. Environmental Protection Agency). Despite the long-standing use of mysids in toxicity testing, little information exists on their endocrinology, and few studies have focused on the potential of these animals for evaluating the effects of hormone-disrupting compounds. Therefore, the question remains as to whether the current standardized mysid endpoints can be used or adapted to detect endocrine disruption, or if new procedures must be developed, specifically directed at evaluating hormone-regulated endpoints in these animals. This review summarizes the ecological importance of mysids in estuarine and marine ecosystems, their use in toxicity testing and environmental monitoring, and their endocrinology and important hormone-regulated processes to highlight their potential use in assessing environmental endocrine disruption.
Modeling the fate of polychlorinated biphenyls in the inner Oslofjord, Norway
Authors: Breivik Knut , Bjerkeng Birger , Wania Frank , Helland Aud , Magnusson Jan 
Published: November 2004

Abstract
A dynamic, segmented, multimedia fate and transport model has been developed, evaluated, and applied to gain insight regarding the behavior of seven polychlorinated biphenyl (PCB) congeners in the Inner Oslofjord (Norway). A comparison with a dated sediment core reveals that the model is not capable of reproducing some key features of the observed, historical, long-term trend in sediments, although better agreement is observed for six of seven PCB congeners over the last two decades. The model also underestimates the concentrations of PCBs in surface sediments in areas adjacent to the city of Oslo (Norway). In general, deviations between modeled and observed concentrations indicate that the historical emissions and discharges of PCBs are not sufficiently characterized and described. Net fluxes predicted by the model suggest that several congeners may have experienced a reversal of air-water and seawater-sediment exchange during the last decade or even earlier. The present study further suggests that the benefit of the proposed removal of the most contaminated sediments of the Inner Oslofjord needs to be assessed, with consideration of the relative contribution of current atmospheric inputs as well as the leaching of PCBs from less contaminated sediments.
Model verification of thermal programmed desorption-mass spectrometry for estimation of release energy values for polycyclic aromatic hydrocarbons on mineral sorbents
Authors: Nicholl Sara I. , Talley Jeffrey W. , Silliman Stephan 
Published: November 2004

Abstract
The physical availability of organic compounds in soil and sediment strongly influences their bioavailability and toxicity. Previous work has indicated that physical availability changes throughout the processes of aging and treatment and that it can be linked to the energy required to release the compound from its sorbent matrix, with a higher energy indicating a more tightly bound compound. This study focused on determining release energy values for various mineral geosorbents (glass beads, sand, and kaolin) contaminated with a 16 polycyclic aromatic hydrocarbon (PAH) mixture. The sorbents were analyzed using thermal program desorption/mass spectrometry (TPD/MS) and the release energy values were calculated from the resulting thermograms utilizing a nonlinear fit of the analytical solution to a simplified version of the Polanyi-Wigner equation. This solution method resulted in a series of combinations of values for the pre-exponential factor (v) and release energy (E) that produced desorption rate curves with similar errors when fit to actual data sets. These combinations can be viewed as an error surface, which clearly shows a valley of minimum error values spanning the range of both E and v. This indicates that this method may not provide a unique set of E- and v-values and suggests that the simplified version of the Polanyi-Wigner equation cannot be used to determine release energy based on TPD data alone.
Digestive bioavailability to a deposit feeder (Arenicola marina) of polycyclic aromatic hydrocarbons associated with anthropogenic particles
Authors: Voparil Ian M. , Burgess Robert M. , Mayer Lawrence M. , Tien Rex , Cantwell Mark G. , Ryba Stephen A. 
Published: November 2004

Abstract
Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability of PAHs from fly ashes, coal dusts, diesel soots, tire tread materials, and urban particulates. We found that gut fluids solubilize significant concentrations of PAHs from two tire treads, two diesel soots, and the urban particulates. However, PAHs in fly ashes and coal dusts were not available to the digestive agents in gut fluid. Potential digestive exposure to PAHs is much greater than that predicted to be available from these materials using equilibrium partitioning theory (EqP). Amending an already-contaminated sediment with fly ash decreased phenanthrene solubilization by gut fluid. In contrast, addition of tire tread to the sediment resulted in increased solubilization of four PAHs by gut fluid. Therefore, addition of certain types of anthropogenic particles to sediments may result in an increase in bioavailable PAHs rather than a net decrease, as predicted by EqP. Difficulty in predicting the amount of change due to amendment may be due to interactions occurring among the mixture of compounds solubilized by gut fluid.
Evaluation of the role of black carbon in attenuating bioaccumulation of polycyclic aromatic hydrocarbons from field-contaminated sediments
Authors: Sundelin Brita , Wiklund Ann-Kristin Eriksson , Lithner Göran , Gustafsson Örjan 
Published: November 2004

Abstract
The significance of black carbon (BC) for the bioavailability of polycyclic aromatic hydrocarbons (PAHs) was examined by using historically contaminated intact sediment cores in laboratory exposure experiments with the deposit-feeding amphipod Monoporeia affinis. Log values of amphipod biota–sediment accumulation factors (BSAFs) were significantly related to log BC, whereas log BSAFs were related to log octanol–water partition coefficients only in background sediments containing less BC. In the background sediments, the BSAF for polycyclic aromatic hydrocarbons (PAHs) was 1 to 2 for phenanthrene, with lower values for more hydrophobic PAHs, indicating an increase in nonequilibrium conditions with increasing PAH molecular size. For the near-equilibrated phenanthrene and fluoranthene, higher BSAFs were measured during exposure to background sediments, with BSAF decreasing to &lt;0.1 in contaminated sediments in the Stockholm waterways. In situ caged mussels (Dreissena polymorpha) exhibited field BSAF values (relative to sediment-trap–collected suspended matter) for polychlorinated biphenyls (PCBs) of 0.1 to 0.4, but for PAHs of similar hydrophobicity and molecular size, the field BSAFs were much lower and in the range 0.002 to 0.05. This PAH–PCB dichotomy is consistent with recently reported much stronger binding to diesel soot (a form of BC) for PAHs than for PCBs of equal hydrophobicities. Lower BSAFs for the near-equilibrated PAHs (phenanthrene and fluoranthene) in the urban sediments relative to the background sediments were consistent with the larger presence of BC in the urban sediments. This study provides the first linked BSAF–BC field data that supports a causal relationship between strong soot sorption and reduced bioavailability for PAHs.
Comparison of accumulation of micropollutants between indigenous and transplanted zebra mussels (Dreissena polymorpha)
Authors: Bervoets Lieven , Voets Judith , Chu Shaogang , Covaci Adrian , Schepens Paul , Blust Ronny 
Published: November 2004

Abstract
Zebra mussels (Dreissena polymorpha) were exposed at 12 canals and lakes situated in Flanders (Belgium), in cages for six weeks during the summer of 2002. Accumulation of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene, and trace metals were measured in the transplanted mussels and levels compared to levels in indigenous mussels. Additionally, zebra mussels were exposed at a small lake in the vicinity of Antwerp (Belgium), and accumulation of contaminants was followed for an extended period from December 2001 to April 2002. Analysis of the pollutants in the indigenous mussels showed that the selected sites displayed a wide range of pollution from near to background to very high levels of metals and/or organic contaminants when compared to the literature. For organic contaminants and for most metals, comparison of levels between caged and resident mussels revealed no significant differences. Only for cadmium and nickel, significant differences were observed, with levels being either higher (cadmium) or lower (nickel) in caged mussels. For organic contaminants, significant correlations between levels in caged and resident mussels were found with r2 values up to 0.98. For some metals, no or poor correlations were found. At most sites, concentrations of those metals were of the same order of magnitude and comparable to levels in mussels from unpolluted sites. This might explain the absence of significant correlations. When mussels were exposed for an extended period, the concentration of some pollutants increased, whereas others decreased with time. Only in the case of certain metals did levels differ significantly because of the slow depuration of metals already present in the transplanted mussels. This is an additional indication that measured concentrations in transplanted mussels indeed reflected the local situation. With this study, we were able to prove the applicability of transplanted mussels as a biomonitoring tool for the accumulation of pollutants over a wide range of pollution.
Accumulation and distribution of polychlorinated dibenzo-p-dioxin, dibenzofuran, and polychlorinated biphenyl congeners in atlantic salmon (Salmo salar)
Authors: Isosaari Pirjo , Kiviranta Hannu , Lie Øyvind , Lundebye Anne-Katrine , Ritchie Gordon , Vartiainen Terttu 
Published: November 2004

Abstract
Adult Atlantic salmon (Salmo salar) were fed on four diets containing polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) for 30 weeks. Lipid-normalized concentrations showed that all congeners were equally partitioned between whole-fish and fillet samples. Skinned fillet accumulated approximately 30% of the total PCDD/F and PCB content in fish. Accumulation efficiencies in whole fish were 43% for 2,3,7,8-chlorinated dibenzo-p-dioxins and dibenzofurans, 83% for dioxin-like PCBs, and 78% for other PCB congeners. Among PCDD/Fs, tetra- and pentachlorinated congeners were preferentially accumulated in salmon, whereas hepta- and octachlorinated dibenzo-p-dioxins were excreted in the feces. Substitution patterns that were associated with a preferential accumulation of PCBs in salmon included non-ortho substitution and tetrachlorination. Accumulation efficiencies and lipid-normalized biomagnification factors (BMFs) were not influenced by the PCDD/F and PCB concentrations of the diets. Biomagnification (BMF &gt; 1) of tetra- and pentachlorinated dibenzo-p-dioxins and dibenzofurans and of all the PCBs was observed. Differences in the behavior of PCDD/F and PCB congeners resulted in a selective enrichment of the most toxic congeners in salmon.
Morphological responses of Daphnia pulex to Chaoborus americanus kairomone in the presence and absence of metals
Authors: Hunter Kim , Pyle Greg 
Published: November 2004

Abstract
Daphnia pulex neonates develop neck teeth in the presence of predatory kairomone from Chaoborus americanus that are fed D. pulex. These neck teeth reduce the susceptibility of the neonates to predation. Evidence suggests that aqueous metals interfere with chemical communication in fish. The objective of our study was to determine if Cu or Ni at environmentally relevant concentrations affects predatory kairomone response in D. pulex. To test this possibility, D. pulex were placed in increasing waterborne concentrations of Cu or Ni in the presence or absence of predatory kairomone. Both Cu and Ni reduced neck tooth induction in D. pulex neonates in the presence of predatory kairomone. Copper had a significant nonlinear effect on neck tooth length consistent with a hormetic response, where neck tooth length was highest at 5 μg/L Cu, but not significantly different than 0 μg/L Cu at higher Cu concentrations. A Ni concentration of 200 μg/L caused D. pulex to become hypersensitive to Chaoborus regardless of Chaoborus' diet, leading to increased neck tooth number but decreased neck tooth length. Neither Ni nor Cu produced any significant effects on body length or brood size. These results suggest that metal inhibition of neck tooth induction probably occurs along the signal transduction pathway. Impairment of chemosensory response to predatory chemical cues may have widespread ecological consequences in aquatic systems contaminated by metals.
Fate of veterinary antibiotics in a macroporous tile drained clay soil
Authors: Kay Paul , Blackwell Paul A. , Boxall Alistair B. A. 
Published: November 2004

Abstract
The environment may be exposed to veterinary medicines administered to livestock through the application of organic fertilizers to land. For other groups of substances that are applied to agricultural land (e.g., pesticides), preferential flow in under-drained clay soils has been identified as an extremely important mechanism by which pollution of surface waters can occur. This study, therefore, was performed to investigate the fate of three antibiotics from the sulfonamide, tetracycline, and macrolide groups. Pig slurry was applied to a field in arable production in two consecutive years and the fate of the compounds was monitored in the soil and drainage water. Both sulfachloropyridazine and oxytetracycline were detected in soil at concentrations up to 365 and 1691 μg/kg, respectively. Subsequently, peak concentrations of the two substances in drainflow were 613.2 and 36.1 μg/L, although mass losses to the receiving water were less than 0.5%. In contrast, tylosin was not detected at all. These findings could be explained by the persistence and sorption characteristics of the antibiotics, while preferential flow via desiccation cracks and worm channels to the tile drains was found to be the most important route for translocation of the chemicals. Thus, when the soil was disced prior to slurry application, losses were reduced significantly. It is evident that processes governing pesticide fate also apply to veterinary antibiotics.
Influence of multigeneration acclimation to copper on tolerance, energy reserves, and homeostasis of Daphnia magna Straus
Authors: Bossuyt Bart T. A. , Janssen Colin R. 
Published: November 2004

Abstract
A multigeneration acclimation experiment was performed with Daphnia magna exposed to copper to assess possible changes in tolerance and to establish the optimal concentration range (OCEE) of this species. The hypothesis was tested that as the bioavailable background concentration of an essential metal increases (within realistic limits), the natural tolerance (to the metal) of the acclimated/adapted organisms and communities will increase. During 18 months the daphnids were exposed to six different, environmentally relevant, copper background concentrations ranging between 0.5 and 100 μg Cu L−1 (7 × 10−15 and 3.7 × 10−9 M Cu2+). An increase in acute (effect concentration resulting in 50% immobility: 48-h EC50) and chronic copper (effect concentration resulting in 50% or 10% reproduction reduction: 21-d EC50, 21-d EC10) tolerance was observed with increasing exposure concentration. The 48-h EC50 increased significantly from 204 ± 24 μg Cu L−1 to 320 ± 43 μg Cu L−1. A nonsignificant change from 48.0 (47.9–48.0) μg Cu L−1 to 78.8 (66.3–93.6) μg Cu L−1 was noted in the chronic toxicity assays. The optimal concentration range was assessed using different biological parameters (i.e., net reproduction [R0]), energy reserves (Ea), body length measurements, filtration rates, and body burdens. After three generations of acclimation the OCEE ranged between 1 and 35 μg Cu L−1 (2 × 10−14 to 80 × 10−12 M Cu2+). Body burden measurements revealed an active copper regulation up to 35 μg Cu L−1 (80 pM Cu2+). It can be concluded that acclimation of D. magna to copper does occur in laboratory experiments, even at realistic copper background concentrations (10−11– 10−9 M Cu2+). However, it is suggested that this phenomenon is of less importance in the context of regulatory risk assessments. An optimal copper concentration range for D. magna was observed between 1 and 35 μg Cu L−1 (10−14 −10−11 M Cu2+), indicating that copper deficiency can occur in routine laboratory cultures.
Acute and chronic toxicity of nickel to rainbow trout (Oncorhynchus mykiss)
Authors: Brix Kevin V. , Keithly James , DeForest David K. , Laughlin Jim 
Published: November 2004

Abstract
Of the fish species tested in chronic Ni exposures, rainbow trout (Oncorhynchus mykiss) is the most sensitive. To develop additional Ni toxicity data and to investigate the toxic mode of action for Ni, we conducted acute (96-h) and chronic (85-d early life-stage) flow-through studies using rainbow trout. In addition to standard toxicological endpoints, we investigated the effects of Ni on ionoregulatory physiology (Na, Ca, and Mg). The acute median lethal concentration for Ni was 20.8 mg/L, and the 24-h gill median lethal accumulation was 666 nmol/g wet weight. No effects on plasma Ca, Mg, or Na were observed during acute exposure. In the chronic study, no significant effects on embryo survival, swim-up, hatching, or fingerling survival or growth were observed at dissolved Ni concentrations up to 466 μg/L, the highest concentration tested. This concentration is considerably higher than the only other reported chronic no-observed-effect concentration (&lt;33 μg/L) for rainbow trout. Accumulation of Ni in trout eggs indicates the chorion is only a partial barrier with 36%, 63%, and 1% of total accumulated Ni associated with the chorion, yolk, and embryo, respectively. Whole-egg ion concentrations were reduced by Ni exposure. However, most of this reduction occurred in the chorion rather than in the embryos, and no effects on hatching success or larval survival were observed as a result. Plasma ion concentrations measured in swim-up fingerlings at the end of the chronic-exposure period were not significantly reduced by exposure to Ni. Nickel accumulated on the gill in an exponential manner but plateaued in trout plasma at waterborne Ni concentrations of 118 μg/L or greater. Consistent with previous studies, Ni did not appear to disrupt ionoregulation in acute exposures of rainbow trout. Our results also suggest that Ni is not an ionoregulatory toxicant in long-term exposures, but the lack of effects in the highest Ni treatment precludes a definitive conclusion.