bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytochrome P450 and organochlorine contaminants in black-crowned night-herons from the Chesapeake Bay region, USA
Authors: Rattner Barnett A , Melancon Mark J , Rice Clifford P , Riley Walter , Eisemann John , Hines Randy K 
Published: March 2010

Abstract
Black-crowned night-heron (Nycticorax nycticorax) offspring were collected from a relatively uncontaminated coastal reference site (next to Chincoteague National Wildlife Refuge, VA, USA) and two sites in the Chesapeake Bay watershed (Baltimore Harbor, MD and Rock Creek Park, Washington, DC, USA). Hepatic microsomal activities of benzyloxyresorufin-O-dealkylase and ethoxyresorufin-O-dealkylase were significantly elevated (up to sixfold and ninefold induction, respectively) in pipping embryos from the Baltimore Harbor colony compared to the reference site, whereas values in embryos from the Rock Creek Park colony were intermediate. Concentrations of organochlorine pesticides and metabolites in pipping embryos from both sites in the Chesapeake watershed were greater than at the reference site but below the known threshold for reproductive impairment. However, concentrations of 10 arylhydrocarbon receptor-active polychlorinated biphenyl (PCB) congeners and estimated toxic equivalents were up to 37-fold greater in embryos collected from these two sites in the Chesapeake Bay region, with values for toxic congeners 77 and 126 exceeding those observed in pipping heron embryos from the Great Lakes. Monooxygenase activity of pipping embryos was associated with concentrations of several organochlorine pesticides, total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents (r = 0.30–0.59), providing further evidence of the value of cytochrome P450 as a biomarker of organic contaminant exposure. Organochlorine contaminant levels were greater in 10-d-old nestlings from Baltimore Harbor than the reference site but had no apparent effect on monooxygenase activity or growth. These findings demonstrate induction of cytochrome P450 in pipping black-crowned night-heron embryos in the Chesapeake Bay region, probably by exposure to PCB congeners of local origin, and the accumulation of organochlorine pesticides and metabolites in nestling herons from Baltimore Harbor. Bio-monitoring with additional waterbird species (e.g., bald eagle, common tern, great blue heron) that appear to be more sensitive to PCBs than black-crowned night-herons is recommended to document health of waterbirds and remediation of the Chesapeake Bay.
A culture-based assessment of the effects of chlorpyrifos on multiple meiobenthic copepods using microcosms of intact estuarine sediments
Authors: Chandler G Thomas , Coull Bruce C , Schizas Nicholaos V , Donelan Teresa L 
Published: March 2010

AbstractMiobenthos occur at densities of &gt;106/m2 in almost every uncontaminated estuarine sediment of the world, yet few studies have explored their utility for a multiple-species chronic bioassay of sediment contaminant effects. A new approach using laboratory-reared, whole-sediment meiobenthic microcosms was developed to holistically test the sublethal effects of chlorpyrifos on benthic copepod survival, age structure, and reproduction. Entire sediment-dwelling meiofaunal communities from a pristine estuarine preserve were cultured (i.e., net population gains were achieved in controls) for at least a full generation to the known 96-h copepod adult 25% lethal concentration and larval 50% lethal concentration of sediment-associated chlorpyrifos (21–33 μg/kg sediment). As an internal bioassay control, we added and cultured 100 gravid benthic copepods (Amphiascus tenuiremis) in each microcosm to assess the exact rather than relative effects of chlorpyrifos on population growth and dynamics. All but one copepod species reproduced and was cultured successfully for at least 21 d using these techniques. We found no chlorpyrifos effects on total meiobenthic copepod densities, but the predominant naturally occurring copepod Microarthridion littorale, known to be a major prey item of many juvenile fish, was significantly reduced in some chlorpyrifos-spiked microcosms. Other naturally occurring copepods were either unaffected or their growth was enhanced in the presence of chlorpyrifos. Amphiascus tenuiremis, known to be adversely affected at this concentration in 96-h static bioassays, increased dramatically in every microcosm. Species-specific responses of endemic copepods were masked when combined into the more commonly used coarse taxonomic category of total copepods.
Fate of chlorpyrifos in outdoor pond microcosms and effects on growth and survival of bluegill sunfish
Authors: Giddings Jeffrey M , Biever Ronald C , Racke Kenneth D 
Published: March 2010

Abstract
Three series of outdoor pond microcosms were treated with the organophosphorous insecticide chlorpyrifos to determine the fate of this compound and its ecological impact on an aquatic community. A variety of application regimes were used, including a one-time surface spray, three soil-water slurry applications, and combinations of spray and slurry applications. Maximum chlorpyrifos concentrations in microcosm water ranged from 0.03 to 2.58 μg/L. Chlorpyrifos disappeared rapidly after each spray application, probably due to volatilization from surface water, with an initial half-life of about 1 d. In slurry-treated microcosms, and in spray-treated microcosms after initial volatilization, half-lives in water were consistently around 6 d. A small fraction (generally less than 10%) of the chlorpyrifos applied went to the sediment, where it was more persistent than in the water column. The mean length and weight of individual bluegill sunfish (stocked as juveniles before chlorpyrifos application) were unaffected by chlorpyrifos exposure. Survival and total biomass of bluegill were reduced in microcosms exposed to the highest chlorpyrifos concentrations. The inhibition concentrations (IC25) for bluegill survival and total biomass were about 0.4 to 1.9 μg/L, based on maximum measured concentrations or maximum 96-h average concentrations. Bluegill survival and total biomass were unaffected by repeated exposures to chlorpyrifos if the maximum concentrations remained below these levels.
The relative importance of water hardness and chloride levels in modifying the acute toxicity of silver to rainbow trout (Oncorhynchus mykiss)
Authors: Galvez Fernando , Wood Chris M 
Published: March 2010

AbstractStatic-renewal 7-d toxicity tests for silver nitrate (AgNO3) were performed with juvenile rainbow trout (Oncorhynchus mykiss Walbaum). The relative influences of calcium and chloride concentrations on median lethal time (LT50) were assessed. Calcium concentrations were controlled by adding either Ca(NO3)2 or CaSO4, whereas chloride concentrations were adjusted with either NaCl or KCl. For both calcium salts, a 100-fold elevation in concentration increased the LT50 approximately 10-fold. However, a 100-fold elevation in KCl ameliorated silver (Ag) toxicity at least 100-fold, while NaCl protected against Ag toxicity even more substantially, demonstrating the much greater protective effect of chloride relative to calcium. In a separate series of bioassays, fish were exposed to 0.92 μM Ag (100 μg/L as AgNO3) with varying amounts of NaCl titrated into each tank to alter the free [Ag+]. The 7-d LC50 occurred at a [NaCl] of 2,500 μM. Using MINEQL+ (a geochemical speciation program), the predicted free [Ag+] at this LC50 value is 0.0285 μM. Further bioassays were performed in which [chloride] was maintained at either 50 or 225 μM, while total [Ag] was independently varied from 0.0092 to 0.0694 μM (1.0–7.5 μg/L). The 7-d LC50 value was calculated at 0.0294 μM Ag (3.18 μg/L) at a chloride concentration of 50 μM, very similar to the free [Ag+] value of 0.031 μM calculated from an earlier LC50 test at a fixed [chloride] of 730 μM. According to MINEQL+, the estimated [Ag+] at this LC50 value is 0.0289 μM. Although a 7-d LC50 value could not be determined at 225 μM chloride, it was estimated at slightly above 0.0277 μM Ag+. Elevating chloride concentrations from 50 to 225 μM did not alter the accumulation of Ag in the liver. In addition, there were no significant differences in hepatic Ag accumulation between any of the Ag-exposed fish, irrespective of the total Ag concentration used during the exposure. Overall, Ag accumulated to approximately 185 μmol/kg wet weight in all Ag-exposed groups (approximately a 10-fold increase above controls). These results, together with a reanalysis of published data, suggest that Ag toxicity can be correlated with the free Ag ion [Ag+], and that any factors altering Ag+ availability (i.e., chloride) will be expected to modify acute Ag toxicity.
Stress proteins HSP60 and HSP70 in three species of amphipods exposed to cadmium, diazinon, dieldrin and fluoranthene
Authors: Werner Ingeborg , Nagel Roland 
Published: March 2010

AbstractTo investigate the use of stress proteins hsp60 and hsp70 as sublethal biomarkers for contaminant exposure in sediments, two infaunal (Ampelisca abdita, estuarine; Rhepoxynius abronius, marine) and one epifaunal (Hyalella azteca, freshwater) amphipod species were exposed for 24 h to solutions of the heavy metal cadmium, the pesticides diazinon and dieldrin, and the polycyclic aromatic hydrocarbon fluoranthene. All three species are routinely used in standard sediment toxicity tests. Analysis of hsp60 and hsp70 was performed using western blotting techniques with subsequent comparative quantification by densitometry. Results demonstrated compound and species-specific induction of stress protein synthesis. Whereas one member of the hps70 protein family showed the most sensitive response to xenobiotic compounds in H. azteca, several members of the hsp60 protein family were the main proteins induced in A. abdita and R. abronius. Sensitivity of the detected stress protein response was highest in H. azteca with significant effects at concentrations 110-, 50-, &gt;1,000-, and &gt;1-fold lower than LC50 values for cadmium, diazinon, dieldrin, and fluoranthene, respectively. The corresponding values were &gt;5 (cadmium), 0.7 (diazinon), &gt;1 (dieldrin), and 2.9 (fluoranthene) for A. abdita, and &gt;2 (cadmium), 3.1 (diazinon), &gt;100 (dieldrin), and &gt;2.9 (fluoranthene) for R. abronius.
The production of stress ethylene relative to the concentration of heavy metals and other elements in the lichen Hypogymnia physodes
Authors: Garty Jacob , Kauppi Matti , Kauppi Anneli 
Published: March 2010

Abstract
The objective of this study was to examine fluctuations in the production of ethylene by the lichen Hypogymnia physodes indicative of environmental stress caused by air pollutants. In addition, we investigated the accumulation capacity of H. physodes, transplanted in the vicinity of two streets having slow traffic and a highway in the city of Oulu, N. Finland, for a short period (45 d). The amounts of stress ethylene produced by the transplanted lichens was compared with the amounts of airborne elements accumulated in the thallus. H. physodes manifested a high accumulation capacity for Fe and Mg in thalli exposed in either one or both streets with slow traffic in Oulu in comparison with thalli left on the control site in the forest outside of the city. Two of the observed elements, Zn and Fe, exhibited a significant positive correlation with the ethylene concentration detected concomitant with the treatment of lichen thalli with either H2O (pH 6.8) or NaHSO3 (pH 4.0). The concentrations of Pb, Fe, Zn, Mn, and Cu in thalli retrieved from one or both streets with slow traffic (13,600 and 14,290 cars/d) were higher than the concentrations in thalli transplanted in a highway with 25,240 cars/d after 45 d of exposure. Our data thus suggest that the streets with slow traffic and fewer cars are more polluted than the highway.
Synergistic toxicity of atrazine and organophosphate insecticides contravenes the response addition mixture model
Authors: Pape-Lindstrom Pamela A , Lydy Michael J 
Published: March 2010

Abstract
A toxic unit (TU) approach was used to test the response addition model for mixtures of pesticides with differing modes of action. Atrazine was tested in binary and ternary combinations with the organochlorine insecticide methoxychlor and organophosphate insecticide methyl-parathion. Atrazine was also tested in binary combinations with additional organophosphates. The TU for atrazine was set slightly below its water solubility limits (TU = 20 ppm), which is well below its 96-h 50% effective concentration for the fourth instar of the midge, Chironomus tentans. In 96-h acute toxicity tests using C. tentans, atrazine was found to produce synergistic (greater than additive) toxicity in a binary mixture with methyl-parathion. Less than additive toxicity was found for the combination of atrazine with methoxychlor (likely due to the low TU assigned to atrazine). The ternary combination of atrazine + methyl-parathion + methoxychlor was found to be marginally synergistic. Results of toxicity tests with atrazine in binary combinations with other organophosphates indicate more than additive toxicity for all compounds except mevinophos. Possible hypotheses are presented in an attempt to explain the noted synergistic relationship between atrazine and various organophosphorous insecticides. These results suggest that the response addition model does not always accurately predict mixture toxicity for chemicals with differing modes of action.
Octanol/air partitioning of polychlorinated biphenyls
Authors: Kömp Peter , McLachlan Michael S 
Published: March 2010

Abstract
The partitioning of 16 polychlorinated biphenyls (PCBs) between air and 1-octanol was investigated using a fugacity meter. The measurements were conducted over an environmentally relevant temperature range (10–43°C). For a given congener the measured 1-octanol/air partition coefficient KOA was exponentially proportional to the reciprocal temperature. The enthalpy of phase change (octanol to air) ΔHOA ranged from 71 to 93 kJ/mol. Up to log KOA values of 9.37 (corresponding to 2,2′,3,4′,5′,6-hexachlorobiphenyl), the enthalpy of phase change was similar to the enthalpy of vaporization of the subcooled liquid PCB. For the less volatile congeners (log KOA &gt; 9.37), the enthalpies of vaporization exceeded the enthalpies of phase change, the difference increasing with increasing log KOA. Solubilities of the PCBs in 1-octanol were calculated from the data, and the results were in excellent agreement with octanol solubilities calculated using the OCTASOL fragment method. A very good correlation between the measured octanol/air partition coefficients and values calculated from octanol/water and air/water partition coefficients was obtained. This yielded a method to estimate reliably the octanol/air partitioning of all PCB congeners.
Equilibrium partitioning of heavy metals in dutch field soils. I. Relationship between metal partition coefficients and soil characteristics
Authors: Janssen René P T , Peijnenburg Willie J G M , Posthuma Leo , Van Den Hoop Marc A G T 
Published: March 2010

Abstract
Twenty Dutch soils were sampled at sites that were expected to have elevated levels of heavy metals compared to background values. Field-based partition coefficients (Kp) for As, Cd, Cr, Cu, Ni, Pb, and Zn were determined by calculating the ratio of the amount of metal extracted by concentrated HNO3 to the metal concentration in the pore water. Kp values varied widely with metal and soil type and correlated well with soil pH. To a lesser extent amorphous Fe-content and dissolved organic carbon (DOC) also explained part of the variation in Kp values. Thereupon, regression equations based on easily obtainable soil characteristics were derived. External validation of the regression equations showed that predicted log Kp values were in agreement with measured values.
Effects of terbufos on juvenile red swamp crayfish (Procambarus clarkii): Differential routes of exposure
Authors: Fornstrom Cynthia B , Landrum Peter F , Weisskopf Carol P , La Point Thomas W 
Published: March 2010

Abstract
During rain events, terbufos may be transported into aquatic ecosystems via agricultural runoff. Because crayfish are closely associated with sediment, they may be exposed to aqueous terbufos through the gills or by ingesting contaminated sediment, detritus, or plants. Bioavailability of terbufos in food and toxicity of terbufos to crayfish were examined by measuring mortality and acetylcholinesterase (AChE) inhibition and by observing behavior. A 96-h aqueous exposure and a 12-h dietary exposure of juvenile red swamp crayfish, Procambarus clarkii, to terbufos produced median lethal concentrations (LC50s) of 5.9 μg/L (95% CI: 4.4, 8.1) and 4.4 μg/g pellet (95% CI: 2.9, 6.7), respectively. Aberrant behavior, such as loss of motor control and equilibrium, was noted at concentrations almost 50% of the aqueous LC50 and 80% of the dietary LC50. As concentration increased, AChE activity decreased and mortality and aberrant behavior increased. I50s, the percentage of AChE inhibition at which 50% of the crayfish died, for aqueous and dietary exposures were 76.5% (95% CI: 67.4, 85.6) and 86.1% (95% CI: 78.1, 94.1) of control activity, respectively. Based on present study results, terbufos is available for uptake by crayfish through ingestion and causes detrimental effects at concentrations less than expected in agricultural runoff.
Trace-element accumulation by Hygrohypnum ochraceum in the upper Rio Grande Basin, Colorado and New Mexico, USA
Authors: Carter Lisa F , Porter Stephen D 
Published: March 2010

Abstract
Transplanted bryophytes can provide an indication of bioavailability. Rates of accumulation were related to the magnitude of ambient trace-element concentrations; maximal uptake occurred during the first 10 d of exposure. Trace-element concentrations in transplanted bryophytes could potentially be used to predict water and sediment concentrations that represent an integration of conditions over short to intermediate lengths of time, rather than instantaneous conditions as measured using water samples.
Sublethal toxicity of copper to a soil-dwelling springtail (Folsomia fimetaria) (Collembola: Isotomidae)
Authors: Scott-Fordsmand Janeck J , Krogh Paul Henning , Weeks Jason M 
Published: March 2010

Abstract
The collembolan Folsomia fimetaria was exposed to a range of elevated copper (Cu) concentrations in a LUFA-Speyer soil for 7, 14, and 21 d, in a microcosm test. The results showed that F. fimetaria was sensitive to copper, with reproduction being a more sensitive parameter of effect than either growth (measured as final body size) or survivorship. A 10% effective concentration (EC10) of 38 mg Cu/kg was calculated for reproduction, and an EC10 between 509 to 845 mg Cu/kg (depending on sex and developmental stage) was calculated for growth. No mortality was observed for soil concentrations up to 1,000 mg Cu/kg. This study has shown that F. fimetaria populations may with time become severly reduced or may even become extinct (in extreme circumstances) as a result of copper exposure. Although survival of the adults was not affected, toxicity was expressed solely through reproductive failure. The present study has also shown that the duration of copper exposure was not an important factor for the determination of effects during short-term tests with F. fimetaria.
Trophic transfer of sediment-associated polychlorinated biphenyls from meiobenthos to bottom-feeding fish
Authors: DiPinto Lisa M , Coull Bruce C 
Published: March 2010

Abstract
Experiments were conducted to examine the dynamics of the sediment-associated polychlorinated biphenyl (PCB) Aroclor® 1254 using a benthic-based trophic transfer model (sediments to benthic copepods to juvenile fish). Field-collected benthic copepods were exposed to sublethal levels of Aroclor 1254 in sediments for 96 h. Accumulation of PCB was measured in the copepods, and these contaminated copepods were fed to the juvenile fish predator Leiostomus xanthurus in uncontaminated sediments. After gut clearance, whole fish were homogenized and examined for PCB accumulation. Similar experiments with L. xanthurus in which meals of uncontaminated copepods were fed in PCB-contaminated sediments were conducted to determine the relative roles of contaminated sediments and contaminated copepod prey ingestion to PCB transfer. Total PCB transfer as well as PCB congener group contributions were examined. A total of 30 congeners were grouped according to log Kow increments and according to chlorine homologue groups. Copepods exposed to PCB-contaminated sediments to 90 μg/g accumulated PCBs to 326 μg/g dry weight. Accumulation of PCB in fish feeding in contaminated sediments was five times higher than that in fish feeding on contaminated prey in uncontaminated sediments (p = 0.0498). In terms of congener patterns, log Kow grouping provided clearer discrimination between groups. Congener patterns were similar in PCB stock solution, sediments, and copepods and were different in the two fish treatments. Kow group relative accumulation patterns in fish were mixed. The chlorine homologue groups revealed that the fish preferentially accumulated the tetrachlorinated congeners relative to copepods and sediments.
Development and evaluation of triggers for sediment toxicity testing of pesticides with benthic macroinvertebrates
Authors: Maund Steve , Barber Ian , Dulka Joseph , Gonzalez-Valero Juan , Hamer Mick , Heimbach Fred , Marshall Monte , McCahon Peter , Staudenmaier Horst , Wustner David 
Published: March 2010

Abstract
Concerns regarding the potential of pesticides that partition into sediments to affect benthic organisms have led to the development of sediment toxicity test methods. However, not all pesticides have the potential to accumulate in sediments or affect benthic organisms. Thus, a scientific rationale for identifying appropriate compounds (triggering) for regulatory sediment toxicity testing is required. Here we propose that testing should only be required for compounds that are relatively adsorptive and persistent in sediment, and also have the potential for toxicity to invertebrates. Trigger endpoints and values are proposed and include soil aerobic degradation rate (time for 50% degradation to occur ≥ 30 d), soil adsorption coefficients (organic carbon partition coefficient ≥ 1000), and Daphnia acute and chronic toxicity (48-h median effective concentration &lt; 1 mg/L or 21-d no-observed-effect concentration &lt; 0.1 mg/L). These data are available internationally for the majority of pesticides. Where appropriate, these preliminary triggers can be augmented by additional data (e.g., water-sediment degradation studies, toxicity data on benthic species) to make more sophisticated triggering cases or risk assessments. An evaluation of the proposed triggers was performed by reviewing regulatory data from standardized studies on 140 pesticides. A total of 22% of the compounds triggered sediment toxicity testing, of which the majority were insecticides and fungicides. For insecticides, fungicides, and herbicides 44, 27, and 6% of compounds within the group met the triggers, respectively. Those compounds that triggered testing are probably representative of the classes of pesticides that might be expected to raise concerns for sediment toxicity.