bluuebunny/crossref_metadata_2025_split huggingface dataset:
Octylphenol induces vitellogenin production and cell death in fish hepatocytes
Authors: Toomey Barbara Holland , Monteverdi George H , Di Giulio Richard T 
Published: March 2010

Abstract
The effects of octylphenol (OP) on vitellogenin production and cell death in hepatocytes from brown bullhead catfish (Ameriurus nebulosus) were studied. Production of vitellogenin was induced in hepatocytes exposed to 10 to 50 μM OP, whereas a higher concentration of OP (100 μM) induced apoptotic cell death. By 3 h after the addition of 100 μM OP, dying cells showed chromatin condensation and DNA fragmentation as determined by fluorescence microscopy and gel electrophoresis. Later stages of cell death (nuclear membrane breakdown and cell fragmentation into apoptotic bodies) were identified in cells exposed to OP for at least 6 h. Hepatocytes exposed to 100 μM OP also produced less vitellogenin than cells exposed to 50 μM OP. An estrogen receptor antagonist, tamoxifen, greatly decreased vitellogenin production in OP-exposed hepatocytes from male fish but did not decrease cell death in these cells. Thus, although the ability of OP to induce vitellogenin production is likely mediated through interactions with the estrogen receptor, the induction of apoptotic cell death by OP does not appear to be dependent on its estrogenic activity but may be a more general toxic effect.
Efficiencies of polychlorinated biphenyl assimilation from water and algal food by the blue mussel (Mytilus edulis)
Authors: Björk Mikael , Gilek Michael 
Published: March 2010

Abstract
A novel method was used to estimate assimilation efficiencies (AEs) of dissolved and food associated PCBs (IUPAC 31, 49, and 153) by the Baltic Sea blue mussel (Mytilus edulis). Mussels were exposed to radiolabeled PCBs in a series of short-term toxicokinetic experiments at different algal food concentrations, both at apparent steady-state (ASS) and non-steady-state (NSS) conditions in respect to PCB partitioning between water and algae. The PCB AEs were calculated using a physiologically based bioaccumulation model where experimentally determined uptake and exposure rates at ASS and NSS conditions were combined into linear equation systems, which were solved for PCB AE from water and food. A positive relationship between PCB uptake and algae clearance by the mussels was observed for all three PCBs. The PCB AEs from both water and food increased with congener hydrophobicity (octanol/water partition coefficient [Kow]), but AEs decreased with increases in water pumping and filtration rate of the mussels, respectively. The average contribution of food-associated PCB to the total uptake also increased with Kow from approximately 30% for PCB 31 and PCB 49 to 50% for PCB 153, mainly as a consequence of increased sorption to the algal food.
Hydrophobic organic contaminants in surficial sediments of baltimore harbor: Inventories and sources
Authors: Ashley Jeffrey T.F , Baker Joel E 
Published: March 2010

Abstract
The heavily urbanized and industrialized Baltimore Harbor/Patapsco River/Back River system is one of the most highly contaminated regions of the Chesapeake Bay. In June 1996, surficial sediments were collected at 80 sites throughout the subestuarine system, including historically undersampled creeks and embayments. The samples were analyzed for a suite of hydrophobic organic contaminants (HOCs) consisting of 32 polycyclic aromatic hydrocarbons (PAHs) and 113 polychlorinated biphenyl (PCB) congeners. Total PAH and total PCB concentrations ranged from 90 to 46,200 and 8 to 2,150 ng/g dry weight, respectively. There was enormous spatial variability in the concentrations of HOCs, which was not well correlated to grain size or organic carbon content, suggesting nonequilibrium partitioning and/or proximity to sources as important factors explaining the observed spatial variability. High concentrations of both classes of HOCs were localized around major urban stormwater runoff discharges. Elevated PAH concentrations were also centered around the Sparrow's Point Industrial Complex, most likely a result of the pyrolysis of coal during the production of steel. All but 1 of the 80 sites exceeded the effects range-low (ERL) for total PCBs and, of those sites, 40% exceeded the effects range-medium (ERM), suggesting toxicity to marine benthic organisms would frequently occur. Polychlorinated biphenyl homolog patterns most closely resembled Aroclor 1260 at sites around areas of high concentration of industrial outflows and urban runoff. Conversely, those sites further from suspected municipal and industrial discharges had patterns resembling that of Aroclor 1254. We suggest the heavier chlorinated pattern is indicative of near-source emissions of PCBs. The lighter chlorinated PCB patterns observed are similar to those found in mainstem Chesapeake Bay sediments and may reflect a more weathered pattern or one derived, in part, from air-water exchange of gaseous PCBs. Using principal component analysis, differences in PAH signatures were discerned. Higher molecular weight PAHs were enriched in signatures from sediments close to suspected sources (i.e., urban stormwater runoff and steel production complexes) compared to those patterns observed at sites further from outfalls or runoff. Due to varying solubilities and affinities for organic matter of the individual PAHs, partitioning of the heavier weight PAHs may enrich settling particles with high molecular weight PAHs. Lower molecular weight PAHs, having lower affinity for particles, may travel from the source to a greater extent.
Modification of metal partitioning by supplementing acid volatile sulfide in freshwater sediments
Authors: Leonard Edward N , Mount David R , Ankley Gerald T 
Published: March 2010

Abstract
Acid volatile sulfide (AVS) is a component of sediments that complexes some cationic metals and thereby influences the toxicity of these metals to benthic organisms. Experimental manipulation of AVS in metal-contaminated sediments may provide a means to neutralize toxicity due to metals and thereby help assess the cause of sediment toxicity. This study evaluated the effect of spiking FeS, Na2S, and Na2S/FeSO4 combined on the concentration of AVS, simultaneously extracted metals (SEM), and pore-water metals in uncontaminated and metal-enriched sediments. Experiments with solid FeS showed comparatively low effectiveness in increasing AVS. Spiking with either Na2S or Na2 S/FeSO4 combined increased AVS and/or reduced SEM metal in Cd-, Zn-, and Ni-spiked sediments and in a Cu-contaminated sediment collected from the field. Spiking with Na2S/FeSO4 caused marked reductions in dissolved metal concentrations in the pore waters of these sediments; spiking with Na2S alone caused an apparent elevation in pore-water (Cu) metal that we believe is an artifact of metal sulfide formation in the filtered pore water. When the Na2S/FeSO4 treatment was evaluated under conditions simulating those in sediment toxicity tests, alterations of AVS/SEM were nearly quantitative, except for Ni-spiked sediment, which showed lower efficiency than the Cd, Zn, or Cu sediments. It appears that AVS spiking holds promise for the experimental manipulation of metal toxicity in sediments.
Rainbow trout cell bioassay-derived relative potencies for halogenated aromatic hydrocarbons: Comparison and sensitivity analysis
Authors: Villeneuve Daniel L , Richter Catherine A , Blankenship Alan L , Giesy John P 
Published: March 2010

AbstractRainbow trout hepatoma cells, stably transfected with a luciferase reporter gene under control of dioxin-responsive elements (RLT 2.0 cells) were used to derive relative potencies (RPs) for a variety of halogenated aromatic hydrocarbons (HAHs) that are structurally similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This in vitro bioassay utilizes 96-well microplates, which provide high sample throughput and assay efficiency without affecting sensitivity. The RLT 2.0-derived potencies for dioxin and furan congeners, relative to 2,3,7,8-TCDD, ranged from 0.917 for 1,2,3,4,7,8-hexachlorodibenzofuran to 0.208 for 1,2,3,7,8-pentachlorodibenzofuran. All mono- and di-ortho polychlorinated biphenyls (PCBs) tested had RPs that were orders of magnitude less than TCDD, but point estimates could not be determined. The RLT 2.0-derived RPs were found to be comparable to both other rainbow trout-specific RPs and RPs based on mammalian bioassays. Sensitivity analysis suggested that the range of uncertainty associated with TCDD equivalent (TEQ) estimates based on RLT 2.0-derived RPs is approximately 10-fold. Within this degree of uncertainty and the context of this study, the RLT 2.0 bioassay showed no definitive biases or inaccuracies relative to similar mammalian- or fish-specific in vitro bioassays. Thus, the RLT 2.0 bioassay appears to be a useful tool for evaluating dioxinlike potency of HAHs to fish.
Dietary uptake efficiency of 2,2ǐ,4,4ǐ,5,5ǐ-hexachlorobiphenyl in yellow perch and rainbow trout: Role of dietary and body lipids
Authors: Dabrowska Henryka , Fisher Susan W , Dabrowski Konrad , Staubus Alfred E 
Published: March 2010

AbstractDietary uptake efficiency (α) and elimination rate constants (kd) of 2,2ǐ,4,4ǐ,5,5ǐ-hexachlorobiphenyl (HCBP) were determined in two fish species, yellow perch and rainbow trout, to investigate the influence of dietary and body lipid levels on bioaccumulation. Groups of juvenile fish with significant differences in percent body lipid were fed with a low-fat(LF) or high-fat (HF) diet spiked with 5 or 50 ppb of 14C-HCBP for 32 d. Thereafter, fish were fed an uncontaminated LF or HF diet to allow for elimination of HCBP. Feeding and growth rates were quantified. There were eight fish lipid/dietary lipid/HCBP concentration exposure combinations for each species. Four fish from each exposure were collected at the beginning of the study and at 10-17-d intervals during exposure and elimination periods for lipid and 14C-HCBP analysis. The a values ranged from 74 to 95% in yellow perch and from 79 to 99% in rainbow trout. The greatest a values, of 95 to 99%, were found in fish given diets with 5 ppb HCBP. Uptake of HCBP was influenced by both dietary and body lipids and depended on the current status of both lipid pools. The elimination rate constants were in the range of 0.000 to 0.004 d−1 in yellow perch and 0.003 to 0.010 d−1 in rainbow trout. No significant differences in elimination rate constants between HF and LF fish groups were found. In fish on a constant dietary lipid regime, the kd values tended to be less in HF than in LF fish. However, in fish groups offered diets with a change in lipid regime, the kd tended to be greater. Lipid × time interactions in the HF and LF fish groups undergoing a change in lipid regime indicated that the kd values, like the a values, were influenced by both lipid pools. Changes in elimination rates due to dietary/body lipid status impacted BAFs more strongly than changes in uptake efficiencies. The BAFs were in the range of 1.11 to 2.49 in yellow perch and 1.5 to 4.3 in rainbow trout.
Sublethal responses of largemouth bass to parasites and organochlorines
Authors: Macrury Nicole K , Johnson Brett M 
Published: March 2010

Abstract
Largemouth bass (Micropterus salmoides) at the Rocky Mountain Arsenal National Wildlife Refuge (RMA) experience chronic organochlorine exposures and parasitism by nematodes (Contracaecum spiculigerum) and digenean flukes (Posthodiplostomum minimum centrarchi). We investigated the influences of nematode intensity, fluke intensity, and whole-body organochlorine concentrations on growth of juvenile RMA bass. Lifetime growth, or age-specific lengths, of bass in three RMA lakes were within the range observed for bass in five reference lakes. However, interlake comparisons can be confounded by differing environmental conditions. Therefore, we conducted mesocosm and laboratory studies to compare growth, consumption, and feeding behavior between RMA bass and bass that had little contaminant or parasite exposure. Mean growth rates of RMA bass were 45% lower compared with hatchery bass in experimental ponds. However, regression analysis revealed that parasite and organochlorine burdens were not negatively associated with either short-term growth or age-specific lengths of RMA bass. Hatchery bass growth was likely higher due to their experience with culture pond conditions. In feeding trials, RMA bass exhibited similar food conversion efficiency and consumption rates and significantly elevated feeding activity compared with hatchery bass. This research demonstrates that current parasite and organochlorine loads had benign influences on growth of juvenile RMA bass.
Costs of chronic waterborne zinc exposure and the consequences of zinc acclimation on the gill/zinc interactions of rainbow trout in hard and soft water
Authors: Alsop Derek H , McGeer James C , McDonald D Gordon , Wood Chris M 
Published: March 2010

Abstract
Juvenile rainbow trout were exposed to zinc in both moderately hard water (hardness = 120 mg CaCO3/L, pH = 8.0, Zn = 150 μg/L or 450 μg/L) and soft water (hardness = 20 mg CaCO3/L, pH = 7.2, Zn = 50 μg/L or 120 μg/L) for 30 d. Only the 450 μg/L zinc—exposed fish experienced significant mortality (24% in the first 2 d). Zinc exposure caused no effect on growth rate, but growth affected tissue zinc levels. Whole body zinc levels were elevated, but gills and liver showed no consistent increases relative to controls over the 30 d. Therefore, tissue zinc residues were not a good indicator of chronic zinc exposure. After the 30-d exposure, physiological function tests were performed. Zinc was 5.4 times more toxic in soft water (control 96 h LC50s in hard and soft water were 869 μg/L and 162 μg/L, respectively). All zinc-exposed trout had acclimated to the metal, as seen by an increase in the LC50 of 2.2 to 3.9 times over that seen in control fish. Physiological costs related to acclimation appeared to be few. Zinc exposure had no effect on whole body Ca2+ or Na+ levels, on resting or routine metabolic rates, or on fixed velocity sprint performance. However, critical swimming speed (UCrit) was significantly reduced in zinc-exposed fish, an effect that persisted in zinc-free water. Using radioisotopic techniques to distinguish new zinc incorporation, the gills were found to possess two zinc pools: a fast turnover pool (T1/2 = 3–4 h) and a slow turnover pool (T1/2 = days to months). The fast pool was much larger in soft water than in hard water, but at most it accounted for &lt;3.5% of the zinc content of the gills. The size of the slow pool was unknown, but its loading rate was faster in soft water. Chronic zinc exposure was found to increase the size of the fast pool and to increase the loading rate of the slow pool.
Modeling the toxicity of amide herbicides using the electrotopological state
Authors: Gough Jonathan D , Hall Lowell H 
Published: March 2010

Abstract
The toxicity (rat, acute, oral LD50) of a set of 50 amides that serve as herbicides is modeled using the electrotopological state indices (E-state) with multiple linear regression. A five-variable model produces sound statistics: r2 = 0.75, s = 0.23. The cross-validation statistics indicate a model useful for prediction: r2press = 0.65, spress = 0.27. Further, a set of nine compounds was set aside for testing the model. The mean absolute error for the test set is MAE = 0.27, supporting the claim that the model may be used for prediction. Structure interpretation is given for each variable so that the model may be used to assist in design of molecules with lower toxicity.
Differentiation of polychlorinated dibenzo-p-dioxin and dibenzofuran sources in coastal British Columbia, Canada
Authors: Bright Doug A , Cretney Walter J , Macdonald Robie W , Ikonomou Michael G , Grundy Stephen L 
Published: March 2010

Abstract
Multivariate pattern analysis techniques, principal components analysis, and polytopic vector analysis (PVA) were used to apportion sources of dioxins and furans to Howe Sound and the lower Strait of Georgia marine ecosystem, British Columbia, Canada, based on deposition in recent sediments. In sediment cores collected in 1990, differences between congeners in the depth of maximum concentration suggested the influence over time of several different sources. Those with a predominance of hexachlorinated dibenzodioxins and 2,3,7,8-tetrachlorodibenzofuran comprised one of the major contributions to the sediment core samples and surficial samples collected from Howe Sound, consistent with past inputs of pulpmill effluent. For most sediment samples, however, over 50% of the composition was attributable to a separate source with octachlorodibenzo-p-dioxin (OCDD) as the dominant congener, followed by heptachlorodibenzo-p-dioxins with small amounts of heptachlorodibenzofuran and octachlorodibenzofuran (OCDF). This source signature is consistent with the composition of dioxins/furans in formulations of pentachlorophenol-based wood preservatives, which were used extensively in British Columbia, Canada prior to the mid-1980s. This major input signature to the greater Strait of Georgia cannot be unequivocally ascribed to PCP use and disposal, however, since several other dioxin/furan sources also exhibit a highly similar composition, one dominated by OCDD. For example, source signatures similar to PCP formulations include those from diesel emissions, coal combustion, municipal solid waste, or other incineration stack emissions (fly ash, in particular), chimney soot from oil central heating, black-liquor recovery furnace flue gas, and scrap wire and car incineration. Further research is required to discriminate among the OCDD-containing sources and, hence, provide for improved future source management.
Effects of organic enrichment and burrowing activity of the polychaeteNeries diversicoloron the fate of tetrachlorobiphenyl in marine sediments
Authors: Gunnarsson Jonas S , Hollertz Karin , Rosenberg Rutger 
Published: March 2010

AbstractThe effects of organic enrichment and burrowing activity of the infaunal polychaete Nereis (Hediste) diversicolor on the distribution of 14C-3,3′,4,4′-tetrachlorobiphenyl (TCB) were studied in an experimental benthic system. Organic enrichment of the sediment was provided by a mixture of the diatom Skeletonema costatum and the sea lettuce Ulva lactuca. Organic matter and TCB were both initially added to a surface sediment layer of the microcosms. A factorial design with organic enrichment (control vs enriched) and bioturbation (presence or absence of N. diversicolor) as fixed factors and concentration of TCB in sediment, water, and biota as dependent variables allowed us to test the four combinations. Release of TCB from the sediment to the water column was measured in the outflowing water of the aquaria. After 28 d of exposure, TCB concentrations were measured in animals, feces, sediment cores, burrows, sediment surface, and in sulfur bacteria mats. Both bioturbation and organic enrichment enhanced the release of TCB from the sediment to the water column. The greatest effect was caused by the combination of the two factors, which increased release rates by 280% compared with controls. No general downward transport and vertical redistribution of TCB in the sediment were observed. However, TCB concentrations were significantly higher in the burrow linings of the worms than in the bulk sediment. Increased TCB accumulation by the animals was observed following organic enrichment, which was considered to be the result of selective feeding on TOC-rich contaminated food particles. The organic enrichment also stimulated the production of sulfur bacteria mats, which were found to accumulate high TCB concentrations. Our results contradict those of several other studies that have reported a reduced bioavailability of organic contaminants with increasing sedimentary organic carbon content. Our study suggests that the quality of the organic matter should be considered in the evaluation of exposure in benthic organisms.
Efficient shedding of accumulated metals during metamorphosis in metal-adapted populations of the midge Chironomus riparius
Authors: Groenendijk Dick , Kraak Michiel H S , Admiraal Wim 
Published: March 2010

Abstract
Metal accumulation and loss during metamorphosis were investigated in Chironomus riparius populations in a metal contaminated lowland river. Cadmium and zinc levels were measured in imagoes and larvae at reference and metal-exposed sites. It was hypothesized that the relationship between metal concentrations in biota and environmental compartments would be influenced by the presence of metal-adapted chironomids. In contrast to the large interpopulation differences in larval body burdens of cadmium, body burdens in imagoes vanished to background levels for all midge populations. This indicated that any cadmium accumulated in larval stages was lost during metamorphosis. This nearly 100% efficiency in shedding of cadmium is most likely caused by an increased metal handling capacity present in exposed midges. In agreement with the cadmium measurements, larval body burdens of zinc showed also highly significant interpopulation differences. In contrast with the cadmium values, however, body burdens of zinc in imagoes showed highly significant interpopulation differences and differences were even recorded between the two exposed sites, indicating interpopulation differences in shedding capacity for zinc. It is concluded that the highly efficient shedding of accumulated metals reflected the metal adaptation recorded in earlier studies of metal-exposed C. riparius populations from the River Dommel. Based on the differences in metal accumulation and the differences found in shedding of metals between the two exposed midge populations, it was concluded that population differentiation due to metal stress is a gradual process rather than an all-or-nothing situation.
Bioassays for the detection of chemicals that can form bioactivation-dependent reactive free radicals
Authors: Sanderson J. Thomas , Commandeur Jan N. M , van Wezel Annemarie , Vermeulen Nico P E 
Published: March 2010

Abstract
In vitro bioassays were developed for the detection of chemicals that can be bioactivated to reactive free radical species in microsomal fractions. Two methods were deployed, a down-scaled spectrophotometric method for the detection of chemicals that can cause lipid peroxidation using the measurement of thiobarbituric acid-reactive substances (TBARS) and a fluorometric method for the detection of chemicals that can undergo redox cycling to generate superoxide radicals based on the detection of hydrogen peroxide. The response of these systems to prototypical and environmentally relevant chemicals, including tetrachloromethane and paraquat, was examined. The detection limit of the lipid peroxidation bioassay, based on the formation of TBARS, was about 1 μM for tetrachloromethane; that of the bioassay for redox cylers, based on the production of hydrogen peroxide, was about 2 μM for paraquat and about 100-fold lower for the potent redox cycler 2,3,5,6-tetramethylbenzoquinone (TMBQ). Several binary mixtures of chemicals were tested for potential nonadditive effects in both in vitro systems. Some antagonistic effects among halogenated methanes were observed in the lipid peroxidation assay. In the hydrogen peroxide production assay, greater than additive effects were seen between small concentrations of paraquat and TMBQ. A number of surface water concentrates from several locations in The Netherlands, with various levels of chemical contamination, exhibited a weak response in the hydrogen peroxide production assay. Acetone was found to interfere with the response of the bioassay to redox cyclers and, therefore, the water concentrates (originally in acetone) were transferred to ethanol prior to testing. A good correlation was observed between the response of the water concentrates in the hydrogen peroxide production assay and their acute toxicity in Daphnia magna. No correlation was observed between this bioassay response and toxicity in the MicrotoxTM assay using Photobacterium phosphoreum.