bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoinduced toxicity of fluoranthene to northern leopard frogs (Rana pipiens)
Authors: Monson Philip D , Call Daniel J , Cox Dean A , Liber Karsten , Ankley Gerald T 
Published: March 2010

Abstract
Rana pipiens larvae (96–118 h old) were exposed for 48 h in a flow-through system to clean water or five concentrations (0.89, 2.18, 6.99, 12.0, and 30.6 μg/L) of the phototoxic polycyclic aromatic hydrocarbon (PAH) fluoranthene. Following this uptake period, the larvae were divided into four groups: one for immediate tissue residue analysis, a second for residue analysis following 48 h of depuration in clean water, and two for a 48-h exposure in clean water to ultraviolet (UV) light at two different levels. At the highest treatment, mean (±SD) UVA (310–390 nm) intensity was 8.12 ± 0.19 × 102 μW/cm2, whereas at a lower treatment the UVA intensity was 4.45 ± 0.05 × 102 μW/cm2. Larval frogs bioaccumulated fluoranthene in direct proportion to the water exposure concentrations, with initial whole-body PAH concentrations of 1.48, 3.53, 4.85, 11.3, and 18.7 μg/g at the five treatment levels. No mortality of the animals occurred during the 48-h uptake phase. When the frogs were placed in clean water, the fluoranthene was rapidly depurated, with up to 80% lost in 48 h. Exposure to UV light following fluoranthene exposure significantly enhanced toxicity of the PAH. Median time to death decreased as the product of UVA light intensity and fluoranthene body residue increased. For larval R. pipiens, sufficient tissue residues of fluoranthene were bioaccumulated within 48 h, at water exposure concentrations in the range of 2 to 10 μg/L, to be lethal when combined with a UVA exposure simulating a fraction of summertime, midday sunlight in northern latitudes.
Comparison between the effects of the phytosterol β-Sitosterol and pulp and paper mill effluents on sexually immature rainbow trout
Authors: Tremblay Louis , Kraak Glen Van Der 
Published: March 2010

AbstractSmaller gonads, delayed sexual maturity and depression of sex steroids have been reported in fish exposed to pulp and paper mill effluents. β-Sitosterol, a phytosterol present in pulp and paper mill effluents that causes reductions in sex steroid secretion in fish, may contribute to some of these effects. In this study, the effects of 17β-estradiol (E2), β-sitosterol from two sources, and two Canadian bleached mill effluents (BME) on sexually immature rainbow trout were investigated in a 21-d in vivo experiment. Both β-sitosterol sources and the two BMEs exerted similar effects. Plasma vitellogenin levels were elevated by all treatments establishing the presence of estrogenic compounds in BME and confirming the estrogenicity of β-sitosterol. β-Sitosterol and BME had little or no effect on testosterone levels. Pregnenolone was significantly reduced by β-sitosterol and BMEs but not by E2, suggesting that this was not an estrogenic effect. Plasma cholesterol was reduced by β-sitosterol but not by BME or E2. Feral female white sucker exposed to BME showed significantly reduced plasma cholesterol compared with females from a reference site. Mixed-function oxygenase (MFO) activity was significantly induced in β-sitosterol- and BME-exposed fish. Both BME and β-sitosterol were shown to affect biological responses through more than one mechanism of action. These studies suggest that β-sitosterol could contribute to some of the physiologic effects of pulp and paper mill effluents.
Persistence and distribution of 4-nonylphenol following repeated application to littoral enclosures
Authors: Heinis Larry J , Knuth Michael L , Liber Karsten , Sheedy Barbara R , Tunell Renee L , Ankley Gerald T 
Published: March 2010

AbstractThe persistence and distribution of 4-nonylphenol (NP) were monitored for 440 d, following application to 18 littoral enclosures (4 × 7–8 m), situated in a 2-ha mesotrophic pond near Duluth, Minnesota. Application was accomplished by subsurface, gravity-fed injection over a 20-d period, with a 2-d frequency, to achieve nominal aqueous concentrations of 0, 3, 30, 100, and 300 μg/L. Mean maximum concentrations in the water over the 20-d application period ranged from 75.7 to 81.0% of nominal for the three highest treatment levels and was 181% of nominal at the lowest treatment level. Water was the major compartment, on a mass balance basis, for NP until 2 to 4 d after the application period, with a mean time to 50% dissipation (DT50) of 0.74 d and a mean time to 95% dissipation (DT95) of 13.8 d. 4-Nonylphenol partitioned to enclosure wall material, macrophytes, and sediment within 2 d of initial application. Macrophytes accumulated maximum NP concentrations of 11.5 and 139 mg/kg 1 to 2 d after the application period at the 30- and 300-μg/L treatment levels, respectively. Mean DT50 and DT95 estimates of NP persistence in/on the macrophytes were 10.3 and 189 d, respectively. Sediment from the 30- and 300-μg/L treatments accumulated maximum dry weight NP concentrations of 2.74 and 27.4 mg/kg, respectively within 20 to 48 d of the first application. The mean sediment porewater NP concentration was 18.6 μg/L for the period 2 to 34 d after application 1 at the 300-μg/L treatment. The sediment was the primary sink for NP 440 d after the initial application with a concentration of 1.97 mg/kg at the 300-μg/L treatment. Mean sediment DT50 and DT95 values were 66.0 and 401 d, respectively, indicating a long-term persistence of NP. Ecocores collected 1 d after the final NP application did not show significant decreases in sediment NP concentration during a 55-d incubation period, corroborating the NP persistence observed in the littoral enclosures.
Preliminary survey of lead poisoning of Steller's sea eagle (Haliaeetus pelagicus) and white-tailed sea eagle (Haliaeetus albicilla) in Hokkaido, Japan
Authors: Kim Eun-Young , Goto Rie , Iwata Hisato , Masuda Yasushi , Tanabe Shinsuke , Fujita Shoichi 
Published: March 2010

Abstract
Concentrations of lead, mercury, and cadmium in the liver, kidney, and muscle of four Steller's sea eagles (Haliaeetus pelagicus) and one white-tailed sea eagle (Haliaeetus albicilla) that were found dead or debilitated and subsequently died in Hokkaido, Japan, from 1986 to 1997 were determined. High lead concentrations (&gt;70 μg/g dry weight) were detected in the liver of two Steller's sea eagles and the white-tailed sea eagle. Lead shot was also found in the intestine and gizzard of one Steller's sea eagle and the white-tailed sea eagle, respectively. Mercury and cadmium concentrations in the tissues of these raptors were low, implying that the toxicities of these elements were negligible. These results indicate that eagles in Hokkaido are suffering from secondary poisoning through ingestion of lead shot embedded in the tissue of their prey.
Randomly amplified polymorphic DNA profile-based measures of genetic diversity in crayfish correlated with environmental impacts
Authors: Krane Dan E , Sternberg David C , Burton G Allen 
Published: March 2010

Abstract
Environmental insults diminish an ecosystem's ability to maintain productive and adaptable populations of organisms. We have analyzed randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR)-generated DNA profiles of naturally occurring rusty crayfish (Orconectes rusticus) populations from eight different populations collected from three separate sets of Ohio (USA) streams and find that changes in the underlying genetic diversity of these populations are significantly correlated (n = 144, p ≪ 0.001) with the extent to which they have been exposed to anthropogenic stressors. Because a population's genetic diversity is largely responsible for its vigor and ability to adapt to subsequent stressors, these results suggest that RAPD-PCR-based measures of genetic diversity may be suitable for development as a sensitive means of directly assessing the impact of stressors upon ecosystems.
Toxicity identification evaluation of metal-contaminated sediments using an artificial pore water containing dissolved organic carbons
Authors: Boucher Anne M , Watzin Mary C 
Published: March 2010

AbstractRecent investigations of sediment-associated pollutants in Lake Champlain indicated significant contamination with As, Mn, and Ni in Outer Malletts Bay, Vermont, USA. Ceriodaphnia dubia exposed to sediment pore water from several sites in Outer Malletts Bay showed repeatable, acute mortality at only one site. A toxicity identification evaluation (TIE) was conducted on pore water to determine the contaminants causing mortality at this site. Unlike most TIE applications, the dilution water used in these tests was formulated to match the hardness, alkalinity, pH, conductivity, and dissolved organic carbon content of the pore water. Results from phase I of the TIE indicated that divalent metals may be responsible for toxicity. Phase II results revealed levels of Mn above LC50 values. Spiking experiments employed in phase III confirmed Mn as the principal toxicant in sediment pore water. The formulated pore water worked well and helped ensure that toxicant behavior was influenced primarily by each TIE manipulation and not by physical and chemical differences between the dilution and site water. Although the Mn toxicity at this site may be the result of its unique geomorphology, this situation underscores the need to look broadly for potential toxicants when evaluating contaminated sites.
Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes
Authors: Kirkwood Andrea E , Chow-Fraser Patricia , Mierle Greg 
Published: March 2010

Abstract
Our study focused on the seasonal dynamics of total Hg in the phytoplankton (living and dead) of two dystrophic shield lakes (Mouse and Ranger). Phytoplankton samples were taken from metalimnetic and hypolimnetic depths in the euphotic zone and were collected and analyzed using ultraclean techniques. In both lakes, phytoplankton Hg (PHYTO-Hg) levels (pg/L) in the metalimnion did not significantly change among dates over the season, although Ranger Lake exhibited significant differences between Hg values measured at the beginning and end of the season. In contrast, PHYTO-Hg significantly increased in the hypolimnia of both lakes by the end of the season. Combined influences of external Hg inputs, remineralization, phytoplankton sedimentation, and increased methylmercury production in the hypolimnia over the season may have contributed to these trends. A highly significant positive relationship existed between PHYTO-Hg levels and whole-water Hg levels (r2 = 0.90), and the mean bioconcentration factor for Hg between the water column and phytoplankton was significantly higher in the hypolimnion compared to the metalimnion for both lakes. In most cases, parameters associated with algal biomass had significant positive correlations with PHYTO-Hg levels. Weight-specific PHYTO-Hg (pg/mg dry weight) varied significantly over the season, and there were interlake differences with respect to seasonal trends. On the basis of these results, we recommend that future sampling regimes include collection of phytoplankton at different limnetic depths throughout the season to account for spatial and temporal variations. Weight-specific Hg levels in phytoplankton could not be explained well by the parameters tested, and the only significant regressions were with parameters reflecting algal biomass. This study provides in situ evidence of Hg accumulation in lake phytoplankton as a function of algal biomass on a seasonal basis (as opposed to biodilution) and stresses the need to confirm these trends in other lake systems.
Evaluation of ability of reference toxicity tests to identify stress in aboratory populations of the amphipodHyalella azteca
Authors: MCnulty Ellen W , Dwyer F James , Ellersieck Mark R , Greer Eugene I , Ingersoll Christopher G , Rabeni Charles F 
Published: March 2010

AbstractStandard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition. at the start of a test. We evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl2, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl2 (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods, such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.
Ecological effects of mosquito control on zooplankton, insects, and birds
Authors: Niemi Gerald J. , Hershey Anne E , Shannon Lyle , Hanowski Joann M , Lima Ann , Axler Richard P , Regal Ronald R 
Published: March 2010

Abstract
We completed an integrated, 6–year study on the potential ecological effects of two mosquito control agents, methoprene (applied as AltosidTM sand granules) and Bacillus thuringiensis var. israelensis (Bti, applied as Vectobac-GTM granules), on zooplankton, insects, and breeding birds in wetlands of central Minnesota, USA, from 1988 to 1993. The study was a before-and-after design with pretreatment (1988-1990) and posttreatment (1991–1993) of 27 wetlands. Study sites were randomly selected and placed within one of three groups of sites, nine control, nine Bti-treated, and nine methoprene-treated. Selected populations of zooplankton, insects, and breeding birds were sampled within each of these wetlands. Insect densities were reduced by 57 to 83% and biomass was reduced by 50 to 83% in the second (1992) and third (1993) years of treatment. No negative effects on zooplankton or breeding birds could be attributed to treatment or changes to insect communities. Many factors may explain the lack of effects on breeding birds including, reductions in insects occurred after the nesting season was over, nest loss rates due to predation were very high (70%) and may have been a greater limiting factor to birds than mosquito control, and the density of breeding birds may be below carrying capacities, especially because not all wetlands in the landscape were treated and sufficient food may have been available. It is unclear what the long-term consequences of insect reductions mean to wetland health. The lack of close coupling between zooplankton, insects, and breeding birds probably reflects the ecological complexity of these wetlands such as the presence of other limiting factors on population distribution and abundance. Although the study period was relatively long (3 years of treatment) compared with most ecological studies of pesticides, it may not have been long enough to fully predict the effects of decades of continued mosquito control.
Influence of food, aquatic humus, and alkalinity on methylmercury uptake by Daphnia magna
Authors: Monson Bruce A , Brezonik Patrick L 
Published: March 2010

Abstract
Six-day-old Daphnia magna were exposed to low concentrations (≤4 ng Hg/L) of methylmercury (MeHg) in synthetic freshwater and synthetic food. Uptake kinetics were determined in 24- to 72-h experiments, measuring both the loss of Hg from water and accumulation in D. magna. Dose-uptake response was linear for MeHg concentrations up to 4.0 ng/L; an initial concentration of 2.0 ng/L was used when other factors were varied. Concentrations of total Hg and MeHg in water and D. magna were measured in treatments with varied hardness and alkalinity, aquatic humus (AH), and food spiked with MeHg versus water spiked with MeHg. Uptake rate coefficients were derived from two versions of a first-order, two-compartment model. The first version assumed constant MeHg concentration; the second accounted for changing MeHg concentration in water over time. Both models accounted for a nonzero starting concentration of MeHg in plankton. Fitted rate coefficients were higher for the second model than the first: the uptake coefficient (ku) was nine times higher (81.6 L/g/h vs 9.00 L/g/h); the depuration coefficient (kd) was twice as high (0.174/h vs 0.084/h). Assuming a constant MeHg concentration for a one-time spike thus underestimates the rate coefficient. The source of MeHg was compared by exposing D. magna for 48 h to MeHg at 2 ng/L in food or water. Daphnia magna accumulated significantly more inorganic Hg (i.e., Hg2+) from spiked food than from spiked water, but accumulation of MeHg was the same from both sources. A similar response was found when D. magna were exposed to a lake water extract of AH at concentrations of C at 3 and 10 mg/L. At the higher AH concentration, total Hg in daphnids was higher, but MeHg was lower, suggesting that AH was a source of inorganic Hg but reduced the bioavailability of MeHg. Exposure of D. magna to MeHg at 2 ng/L in hard or soft water adjusted to pH 6.7 showed no significant difference in MeHg uptake, supporting an argument that hardness and alkalinity per se do not affect MeHg uptake by daphnids.
Ecological risk assessment in a large river-reservoir: 8. Experimental study of the effects of polychlorinated biphenyls on reproductive success in mink
Authors: Halbrook Richard S , Aulerich Richard J , Bursian Steven J , Lewis Lorin 
Published: March 2010

Abstract
As a component of an ecological risk assessment of Poplar Creek (located on the Oak Ridge Reservation [ORR]) and the Clinch River (a large river–reservoir system), fish from Poplar Creek, the Clinch River, and Atlantic Ocean were fed to ranch mink to evaluate reproductive success. Five diets, each composed of 75% fish and 25% normal ranch mink chow, were prepared. Two diets served as reference diets and contained 75% Atlantic Ocean fish or 75% Clinch River fish collected above the ORR. The fish portion of the remaining three diets contained 25, 50, and 75% fish collected from Poplar Creek and 50, 25, and 0% ocean fish, respectively. Five mink groups (eight females and two males each) were each fed one of the prepared diets for 196 days. Polychlorinated biphenyl concentrations were determined in diets and various mink tissues, ethoxyresorufin-O-deethylase (EROD) activity was determined in liver tissue, and reproductive success was evaluated. Concentrations of PCB were greatest in the diet composed of 75% Poplar Creek fish and in tissues from mink fed this diet and their offspring. There was a trend toward decreased adult female and kit weights and reduced mean litter size in mink fed diets containing 75% Poplar Creek fish; however, at 6 weeks of age, kit survival was similar among diet groups. Liver EROD activity significantly increased in adult female mink fed 50 and 75% Poplar Creek fish diets. Estimated dietary concentrations of PCBs were similar to or slightly lower than concentrations associated with adverse effects in experimentally dosed mink. Mercury (Hg) concentrations previously reported in these same mink were below that associated with adverse effects, and there was no indication of additive or synergistic effects from exposure to PCBs plus Hg. It is unlikely that population-level reproductive effects would be observed in mink consuming fish from Poplar Creek on the ORR.
The SED-TOX index: Toxicity-directed management tool to assess and rank sediments based on their hazard—concept and application
Authors: Bombardier Manon , Bermingham Norman 
Published: March 2010

AbstractThis article introduces the Sediment Toxicity (SED-TOX) Index for the assessment and ranking of toxic hazards in sediment. Major features include expression of toxicity responses on a single scale of measurement (dry weight–based toxic units), consideration of multiple routes of exposure (pore water, organic extract, wet sediment, and whole sediment), application of differential treatments to toxicity data depending on the level of response (acute lethal or chronic sublethal), and use of weighting factors to discriminate sediment exposure phases and effect endpoints on the basis of sensitivity. A battery of seven bioassays with four test species (Vibrio fischeri, Escherichia coli, Lytechinus pictus, and Amphiporeia virginiana) was conducted on 49 marine sediment samples collected from six sites at Anse-à-Beaufils and Cap-aux-Meules, which are in the Gulf of St. Lawrence. The SED-TOX scores were calculated for each sampling station and compared with sediment contaminant concentrations. Results indicate that physicochemical characterization is not sufficient to assess contaminated-sediment hazard for organisms; furthermore, using several exposure phases and test species belonging to various trophic levels increases the possibility of correctly identifying toxic sediments. The results of this study indicate that the SED-TOX approach is valuable as a toxicity assessment and ranking tool for sediments. It could easily be combined with other measures of ecosystem disturbance to discriminate between polluted and unpolluted sites.
Transgenerational toxicity of tributyltin and its combined effects with polychlorinated biphenyls on reproductive processes in Japanese medaka (Oryzias latipes)
Authors: Nirmala Kukuh , Oshima Yuji , Lee Richard , Imada Nobuyoshi , Honjo Tsuneo , Kobayashi Kunio 
Published: March 2010

Abstract
Japanese medaka (Oryzias latipes) were fed daily on one of four diets containing tributyltin (TBT), PCBs, a combination of TBT and PCBs, or a control diet (with nothing added). Contaminant doses were 1 μg/g body weight per day for 3 weeks. The combination of TBT and PCB showed additive effects on the spawning of medaka, resulting in a significant reduction in spawning frequency, and on the number of spawned eggs and fertilization success when compared with effects in fish fed either a TBT or PCB diet. The adverse effects on the reproductive success of medaka may have been due to endocrine disruption caused by accumulation of both TBT and PCB. The TBT treatment significantly reduced embryo and larval survival from eggs (279 ng TBT/g), which were spawned from females containing 2,390 ng TBT/g body weight from the TBT diet. This result indicates transgenerational toxicity. The PCB diet caused fewer adverse effects than the TBT diet with respect to spawning frequency, egg survival, hatching, and swim-up success of larvae. When both TBT and PCB were in the diet, there were additive effects on spawning success as noted above but antagonistic effects on embryological success of eggs and swim-up success of larvae.