bluuebunny/crossref_metadata_2025_split huggingface dataset:
An in situ bioassay for estuarine environments using the microalga Phaeodactylum tricornutum
Authors: Santos Matilde Moreira Dos , Moreno-Garrido Ignácio , Gonçalves Fernando , Soares Amadeu M. V. M. , Ribeiro Rui 
Published: March 2010

Abstract
This study aimed at evaluating the potential of an in situ algal bioassay for routine toxicity estimates of potentially contaminated estuarine environments using the microalga Phaeodactylum tricornutum immobilized in alginate beads. The influence of the initial cell density in the beads and of salinity on algal growth was first investigated. The potential of the proposed bioassay was evaluated by comparing laboratory with in situ results. A good growth performance of P. tricornutum was observed at all starting densities of beads. Although the growth rate of P. tricornutum was significantly affected by salinity, acceptability criteria currently adopted in algal assays were met, indicating the suitability of P. tricornutum as a test species for bioassays in estuaries. The large differences observed between the laboratory and in situ responses of P. tricornutum were most probably due to the temperature and light conditions less favorable for algal growth in the field and to the lack of representativeness of water samples compared to the field fluctuating conditions. These results showed the need for in situ assessments, especially in estuarine environments influenced by tides. To a lesser extent, the bioassay itself may also have been responsible for the laboratory and field differences. Further improvements in the bioassay chambers and procedures were also discussed.
Isopod gut microflora parameters as endpoints in toxicity studies
Authors: Drobne Damjana , Rupnik Maja , Lapanje Ales , Strus Jasna , Janc Miha 
Published: March 2010

Abstract
Terrestrial isopods Porcellio scaber (Crustacea) were fed for five weeks on food contaminated by 250, 500, or 1,000 μg of Cd/g or for 10 d on diets with 50 or 250 μg Cd/g food. In both experiments, fecal production rate and colony forming units (CFUs) in the guts were determined. In addition, at the end of 10 d, each distinct colony morphotype obtained in gut samples was purified and characterized. Isolates were separated into 25 groups based on morphological and biochemical characteristics. These bacterial groups were used as units for calculating Shannon equitability indices (J) for each gut. The relative frequencies of the 25 bacterial units were determined in both cadmium groups (50 or 250 μg Cd/g food) and in the control. Cadmium-induced perturbations observed in the gut microbial communities were (1) increased number of morphologically distinct bacterial isolates in the group fed low-cadmium-dosed food (50 μg Cd/g) and reduced number of morphologically distinct bacterial isolates in the group fed high-cadmium-dosed food (250 μg Cd/g) compared with the control, (2) increased or decreased relative frequencies of almost all 25 bacterial units provoked by cadmium-contaminated food, (3) time-dependent increased numbers of gut CFUs in cadmium-fed animals (dose dependence was not observed), and (4) significant changes in community structure described by Shannon equitability indices at lower levels of food contamination (50 μg Cd/g) only. Gut microflora parameters are proposed as additional endpoints in the standardized single-species toxicity test with the terrestrial isopod P. scaber as a means of increasing the ecological relevance of the results.
Relative sensitivity of bull trout (Salvelinus confluentus) and rainbow trout (Oncorhynchus mykiss) to acute copper toxicity
Authors: Hansen James A. , Lipton Josh , Welsh Paul G. 
Published: March 2010

Abstract
Bull trout (Salvelinus confluentus) were recently listed as threatened in the United States under the federal Endangered Species Act. Past and present habitat for this species includes waterways contaminated with heavy metals released from mining activities. Because the sensitivity of this species to copper was previously unknown, we conducted acute copper toxicity tests with bull and rainbow trout (Oncorhynchus mykiss) in side-by-side comparison tests. Bioassays were conducted using water at two temperatures (8°C and 16°C) and two hardness levels (100 and 220 mg/L as CaCO3). At a water hardness of 100 mg/L, both species were less sensitive to copper when tested at 16°C compared to 8°C. The two species had similar sensitivity to copper in 100-mg/L hardness water, but bull trout were 2.5 to 4 times less sensitive than rainbow trout in 220-mg/L hardness water. However, when our results were viewed in the context of the broader literature on rainbow trout sensitivity to copper, the sensitivities of the two species appeared similar. This suggests that adoption of toxicity thresholds that are protective of rainbow trout would be protective of bull trout; however, an additional safety factor may be warranted because of the additional level of protection necessary for this federally threatened species.
AgDrift®: A model for estimating near-field spray drift from aerial applications
Authors: Teske Milton E. , Bird Sandra L. , Esterly David M. , Curbishley Thomas B. , Ray Scott L. , Perry Steven G. 
Published: March 2010

Abstract
The aerial spray prediction model AgDRIFT® embodies the computational engine found in the near-wake Lagrangian model AGricultural DISPersal (AGDISP) but with several important features added that improve the speed and accuracy of its predictions. This article summarizes those changes, describes the overall analytical approach to the model, and details model implementation, application, limits, and computational utilities.
A comparison of the transport and fate of polychlorinated biphenyl congeners in three great lakes food webs
Authors: Morrison Heather A. , Whittle D. Michael , Haffner G. Douglas 
Published: March 2010

AbstractA food web bioaccumulation model was used to compare transport and fate of polychorinated biphenyls (PCB) congeners in three food webs in the Laurentian Great Lakes of North America. The model was used to quantify the contribution of sediment-derived and freely dissolved PCBs to the body burden of aquatic biota. In eastern Lake Erie (OH, USA), almost 100% of the chemical body burden of biota originates from sediment. In western Lake Erie, benthic invertebrates accumulated slightly more than half of their PCB body burden from sediment while fish accumulated less than half of their chemical body burden from sediment. Fish from Lake Ontario, Canada, accumulated less than 30% of their body burden of PCB congeners with log Kow &lt; 6.4 from sediment and approximately half of their body burden of PCB congeners with log Kow ≥ 6.4 from sediment. Field data and the model were also used to determine the effects of declining concentrations of PCBs in water and sediment on concentrations of PCBs in aquatic biota. Results indicate that, as concentrations of PCB congeners in the ecosystem decline, the role of sediment as the source of contaminant to aquatic biota increases. Furthermore, as sediment becomes the predominant source of contaminant to aquatic biota, the concentration of PCB congeners in biota tends to equilibrium with bottom sediment.
A tropical sediment toxicity test using the dipteranChironomus crassiforcepsto test metal bio availability with sediment pH change in tropical acid-sulfate sediments
Authors: Peck Mika R. , Klessa David A. , Baird Donald J. 
Published: March 2010

AbstractThe wetlands of the Magela floodplain of northern Australia, which is the major sink for dissolved metals transported in the Magela Creek system, contain acid-sulfate sediments. The rewetting of oxidized acid-sulfate soil each wet season produces acidic pulses that have the potential to alter the bioavailability of sediment-associated metal contaminants. Acute toxicity tests (72-h mean lethal concentration [LC50]) using the tropical chironomid Chironomus crassiforceps Kieffer showed that copper toxicity decreased from 0.64 mg/L at pH 6 to 2.30 mg/L at pH 4. Uranium toxicity showed a similar trend (36 mg/L at pH 6 and 58 mg/L at pH 4). Sediment toxicity tests developed using C. crassiforceps also showed that both metals were less toxic at the lower sediment pH with pore-water copper toxicity having a lowest-observed-effect concentration of 4.73 mg/L at pH 4 compared to 1.72 mg/L at pH 6. However, a lower pH increased pore-water metal concentrations and overlying water concentrations in bioassays. Hydrogen ion competition on metal receptor sites in C. crassiforceps was proposed to explain the decrease in toxicity in response to increased H+ activity. This study highlights the need to consider site-specific physicochemical conditions before applying generic risk assessment methods.
Toxicity testing using esterase inhibition as a biomarker in three species of the genus Lecane (Rotifera)
Authors: Pérez-Legaspi Ignacio Alejandro , Rico-Martínez Roberto , Pineda-Rosas Arikitza 
Published: March 2010

Abstract
We have developed an esterase inhibition test to investigate the effects of 10 toxicants, including six metals (cadmium, chromium, copper, lead, mercuric chloride, and titanium) and four organics (benzene, ethyl acetate, toluene, and vinyl acetate) in three species of the benthic rotifer genus Lecane (L. hamata, L. luna, and L. quadridentata). Metals affect esterase inhibition by an average value of 4,957-fold greater than the four organics tested for the three rotifer species. Most of the EC50 (effect concentration where a 50% reduction in esterase activity is observed) values correspond to environmentally realistic concentrations. Comparisons of acute-to-chronic ratios among these three species showed that in two species, L. luna and L. quadridentata, esterase inhibition is an outstanding biomarker for most of the toxicants tested.
Hepatic microsomal cytochrome P450S and chlorinated hydrocarbons in largha and ribbon seals from Hokkaido, Japan: Differential response of seal species to ah receptor agonist exposure
Authors: Chiba Issei , Sakakibara Akihito , Iwata Hisato , Ishizuka Mayumi , Tanabe Shinsuke , Akahori Fumiaki , Kazusaka Akio , Fujita Shoichi 
Published: March 2010

AbstractFrom 16 largha seals (Phoca larghá) and 15 ribbon seals (Phoca fasciata) in the coastal waters of Hokkaido, Japan, blubber chlorinated hydrocarbon (CHC) levels and hepatic cytochrome P450 (CYP) catalytic activities and their immunochemically detected protein content levels were measured. Concentrations of DDTs (2,2-bis(4-chlorophenyl)-1,1-dichloroethylene, p,p′-DDE; 2,2-bis(4-chlorophenyl)-1,1-dichloroethane, p,p′-DDD; dichlorodiphenyltrichloroethane, p,p′-DDT), polychlorinated biphenyl congeners (PCBs), and chlordane compounds (oxychlordane, chlordanes, and nonachlors) in both species were in the range of 290 to 5,300, 420 to 4,000, and 130 to 1,500 ng/g lipid weight, respectively. Aryl hydrocarbon receptor (AhR) agonists, non-ortho (IUPAC 77 and 126) and mono-ortho (IUPAC 105, 118, and 156) coplanar PCB congeners, were also detected, and the 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) toxic equivalents (TEQs) were 4.9 to 120 pg TEQ/g lipid weight. Cross-reactive proteins with polyclonal antibodies against rat CYP1A1 and CYP3A2 were notably detected in seal liver microsomes. Interestingly, a polyclonal antibody against rat CYP2B1 recognized proteins only at trace levels. In largha seals, both levels of alkoxyresorufin- (methoxy-, ethoxy-, pentoxy-, and benzyloxyresorufin) O-dealkylase (AROD) activities and proteins detected by polyclonal antibodies against rat CYP1A1 were significantly correlated with the concentrations of individual coplanar PCB congeners, total TEQs, and total PCBs. Threshold concentrations for TEQs in blubber of the largha seal to induce hepatic CYP1A protein and EROD activity were estimated to be 8.5 and 19 pg TEQ/g fat weight, respectively. In ribbon seals, similar correlations were not detected, although the TEQ levels were not significantly lower than those in largha seals. These results suggest that AROD activity and CYP1A1 protein in the liver of the largha seal could be a biomarker for the exposure to AhR agonists such as coplanar PCB congeners. This study also indicates differences in AhR-mediated responses to the CHC exposures between largha and ribbon seals.
Effects of dinoseb on the life cycle ofDaphnia magna: Modeling survival time and a proposal for an alternative to the no-observed-effect concentration
Authors: Chèvre Nathalie , Slooten Kristin Becker-van , Tarradellas Joseph , Brazzale Alessandra R. , Behra Renata , Guettinger Herbert 
Published: March 2010

AbstractRisk assessment is in urgent need of more accurate toxic effect endpoints than those currently in use, especially for low concentrations. Often such endpoints are estimated by analysis of variance, linear interpolation, or smoothing. As these statistical methods are not always satisfactory, some authors have proposed to describe the entire dose-response curves by fully formalized parametric regression models whose parameters have toxicological meaning. These models allow a better evaluation of pollutant effects, including inter- and extrapolation to any other than the measured effect values. Following this line, a four-parameter logistic regression model (standard model) was fitted to survival data of Daphnia magna under pesticide (dinoseb) stress. The heterogeneity of the variance was taken into account with a both-sides logarithmic transformation. Besides the standard model, a hormesis and a threshold model were tested too. These two others models have been described in the literature and might better represent the dose—response function we are looking for. All three models showed a good fit to our data, and the statistics gave no hints as to which model is the most appropriate. As no evidence was seen for hormesis or for the existence of a threshold concentration, we used the simplest, namely, the standard model, for most of our calculations. Model calculations allow the quantification of the effects on individuals' longevity as well as on mean survival time of the population. We used them to define a no-effect value, the statistical-no-effect concentration (SNEC). The SNEC is based on the confidence bands of the modeled regression and represents the highest value for which an effect is statistically not different from the control. The SNEC is an alternative to classical endpoints, like the no-observed-effect concentration (NOEC) or the low-effect concentrations (e.g., EC10, EC5, EC1).
Characteristics of trophic transfer of polychlorinated biphenyls in marine organisms in Incheon North Harbor, Korea
Authors: Kim Seung Kyu , Lee Dong Soo , Oh Jae Ryong 
Published: March 2010

AbstractThe trophic transfer of polychlorinated biphenyls (PCBs) was characterized for zooplankton (primarily Paracalanus spp. and Acartia spp.), pacific oyster (Crassostrea gigas), shore crab (Hemigrapsus penicillatus), and goby (Acanthogobius hasta) in the aquatic system of Incheon North Harbor, Korea. The congener pattern in the species was clearly divided by the main PCB uptake route. Compared with zooplankton and oyster, the fraction of heavier homologues increased in crab and goby that take PCBs from food. Linear relationships were observed between log (fugacity in lipid/fugacity in seawater) and log Kow for all the species. For zooplankton and oyster, such an observation should not be regarded as a true absence of superhydrophobicity, because establishment of equilibrium with seawater was not evident. For crab and goby, the absence of superhydrophobicity was evidenced by the trophic transfer factor that continuously increased with Kow up to 107.8. These results suggest that superhydrophobicity might be species specific. The trophic transfer factors and the fugacity levels in the lipid phase indicated that bioaccumulation in crab and goby advanced beyond the level in equilibrium with seawater in the harbor basin.
Accumulation patterns of polychlorinated biphenyl congeners and organochlorine pesticides in Steller's sea eagles and white-tailed sea eagles, threatened species, in Hokkaido, Japan
Authors: Sakamoto Kentaro Q , Kunisue Tatsuya , Watanabe Mafumi , Masuda Yasushi , Iwata Hisato , Tanabe Shinsuke , Akahori Fumiaki , Ishizuka Mayumi , Kazusaka Akio , Fujita Shoichi 
Published: March 2010

Abstract
Polychlorinated biphenyls (PCBs), including coplanar congeners, hexachlorocyclohexane isomers, chlordane-related compounds, and hexachlorobenzene, were found in the breast muscle of Steller's sea eagles (SSE) and white-tailed sea eagles (WSE) threatened species, collected in Hokkaido, Japan, during the two years from 1998 to 1999. Both PCBs and DDTs were the most notable compounds, with concentrations one to two orders of magnitude higher than the other compounds, that is, from 120 to 39,000 and from 68 to 15,000 ng/g wet weight, respectively. Non-ortho (International Union of Pure and Applied Chemistry [IUPAC] 77, 126, and 169) and mono-ortho (IUPAC 105, 118, and 156)-substituted coplanar PCB congeners amounted to 9.2 to 740 pg/g of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents derived from the World Health Organization, Paris, France (WHO), toxic equivalent factors. The atmospheric PCBs and DDTs in eastern Siberian cities, such as Khabarovsk and Magadan, have been reported to be much higher than Hokkaido and the North Pacific. Thus, we speculated that the eagles might have been contaminated in these areas, where they spend most of the year except winter, which they spend in eastern Siberia. Adult eagles accumulated more PCBs and DDTs than younger ones. The patterns of PCB congeners were also found to change, depending on the age of the eagle examined; adult eagles showed relatively higher proportions of highly chlorinated PCBs than juvenile eagles did. This difference would be related to the efficiency of the excretion and the metabolism of each PCB congener in the eagles.
Toxicity of tributyltin and triphenyltin to early life-stages ofParacentrotus lividus(Echinodermata: Echinoidea)
Authors: Novelli Alessandra Arizzi , Argese Emanuele , Tagliapietra Davide , Bettiol Cinzia , Ghirardini Annamaria Volpi 
Published: March 2010

AbstractSperm cell and embryo toxicity tests using the Mediterranean sea urchin Paracentrotus lividus were performed to assess the toxicity of tributyltin chloride, bis(tributyltin)oxide, triphenyltin acetate, and triphenyltin hydroxide. Toxicity values (mean effective concentration [EC50]) ranged from 2.97 to 18.5 μg/L for sperm cells and from 1.11 to 2.62 μg/L for embryos. For sperm cells, the toxicity of the two tributyl compounds was significantly greater than that of two triphenyl compounds; for embryos, the triphenyl compounds appeared to be more toxic. Study of embryotoxic effects highlighted closely concentration-dependent damages, the most sensitive stages corresponding to the crucial phases of differentiation (gastrula and prisma). Both EC50 and no-observed-effect concentration values for the four organotin compounds are similar to those reported in the literature for early life stages of other marine organisms.
Temporal and spatial variation in plasma thyroxine (T4) concentrations in juvenile alligators collected from lake Okeechobee and the northern Everglades, Florida, USA
Authors: Gunderson Mark P. , Bermudez Dieldrich S. , Bryan Teresa A. , Crain D. Andrew , Degala Satish , Edwards Thea M. , Kools Stefan A. E. , Milnes Matthew R. , Guillette Louis J. 
Published: March 2010

AbstractWe examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site, Water Conservation Area 3A served as an intermediate contaminant exposure site, and Belle Glade served as the high contaminate exposure site. In May 1999, alligators (n = 22) from Water Conservation Area 3A exhibited higher T4 concentrations than animals from both Belle Glade (n= 22; p =0.0003) and Moonshine Bay (n = 33; p = 0.001). In May 2000, alligators (n = 29) Water Conservation Area 3A again exhibited higher T4 concentrations than those from Belle Glade (n = 49; p = 0.02) but not those from Moonshine Bay (n= 40). No sexual dimorphism was observed among mean T4 concentrations within any of the sites during either year (p &gt; 0.05). Animals within all sites exhibited higher T4 concentrations in May 2000 when compared to May 1999. When variance was examined, animals from Water Conservation Area 3A exhibited higher variance in plasma T4 concentrations than those from either Moonshine Bay or Belle Glade. We concluded that mean plasma T4 concentrations did not match the sediment contaminant mixture data presently available to us, whereas variance seems to be a more reliable indicator of contaminant exposure.
Effect of molecular structures on the solubility enhancement of hydrophobic organic compounds by environmental amphiphiles
Authors: Cho Hyun-Hee , Park Jae-Woo , Liu Clark C. K. 
Published: March 2010

Abstract
Amphiphilic molecules, such as humic substances and surfactants, are known to increase the apparent aqueous solubility of hydrophobic organic compounds (HOCs) in the aqueous phase because of their molecular structures, which consist of hydrophilic and hydrophobic moieties. In this study, we examined the effect of the structures of humic acid and HOCs on the sorption of four polycyclic aromatic hydrocarbons (PAHs) and an organochlorine pesticide, p,p′-DDT, to humic acid. As the number of aromatic rings was increased, the extent of solubility enhancement of PAHs by humic acid was increased. Although p,p′-DDT was more hydrophobic than pyrene in this study, the extent of solubility enhancement of p,p′-DDT by humic acid was lower than that of pyrene because of the molecular structures of the solutes. Anionic surfactants with and without aromatic rings also were studied for comparison, and the dianionic surfactant with two benzene rings exhibited similar results with humic acid, unlike the surfactants without and with one benzene ring. The results from this study indicate that bulky molecules, such as p,p′-DDT sorbed with more difficulty to the aggregates of amphiphiles with larger molecules, such as humic substances and the dianionic surfactants.