bluuebunny/crossref_metadata_2025_split huggingface dataset:
Weight loss and net abnormalities ofHydropsyche betteni(caddisfly) larvae exposed to aqueous zinc
Authors: Balch Gordon C , Evans R Douglas , Welbourn Pamela , Prairie Robert 
Published: March 2010

AbstractCaddisfly larvae (Hydropsyche betteni) were collected near a zinc mining operation and exposed to elevated concentrations of zinc in an attempt to determine the efficacy of using weight change and capture net architecture for assessing the toxicological impact of metal exposure. One group of larvae was collected near the mine site (Adjacent) with another collected upstream and away from the mine (Remote). Weight change and capture net architecture was monitored on 400 individually identifiable larvae. The threshold-observed-effect concentration after 13 d was 7.6 mg/L for the Remote group and 30.2 mg/L for the Adjacent group. After 48 d, the highest test concentration of 42 mg/L resulted in a 23 and 19% loss in live-body weight in the Remote and Adjacent groups, respectively, while control larvae from both groups gained 6% in comparison to initial pre-exposure weights. Five weeks of exposure at 22 mg Zn/L or greater was required by both larval groups to statistically reduce the frequency of normal nets, indicating that the sensitivity of the net response was less sensitive than weight loss. Relative differences in weight changes and net architecture strongly suggest that the Adjacent larval group was slightly more tolerant than the Remote and that this increased tolerance may be related to chronic pre-exposure to zinc prior to collection of larvae. This study demonstrates the utility of using weight loss, net architecture, and tissue burdens for assessing the impact of elevated zinc.
Hepatic P4501A activity, plasma sex steroids, and gonadal steroidogenesis in vitro in yellow perch exposed to 3, 3′, 4, 4′, 5-pentachlorobiphenyl
Authors: Dabrowska Henryka , Fisher Susan W , Ciereszko Renata , Dabrowski Konrad , Woodin Bruce R , Stegeman John J 
Published: March 2010

Abstract
Yellow perch were given a single intraperitoneal injection of polychlorinated biphenyl (PCB) 126 dissolved in cornoil at nominal concentrations of 0, 10, 100, and 500 μg/kg body weight. Following the injection, the fish were held for four weeks under photothermal conditions characteristic for Ohio, USA, and fed a commercial fish food. Thereafter, they were sacrificed to examine the PCB 126 concentrations in the liver and to assess the contaminant effects on hepatic P4501A activity, reproductive hormones in plasma, and steroidogenic potential of gonads. The administered doses resulted in liver concentrations of 0.8 (corn oil control), 12.1, 38.9, and 174.5 μg/kg wet tissue weight. Hepatic P4501A indices were differentially affected depending on both the PCB 126 dose and fish gender. In untreated fish, the P4501A protein and ethoxyresorufin-O -deethylase activity were several times lower in females than in males. In treated males, the hepatic P4501A was inhibited by all three PCB 126 doses. In females, a significant P4501A induction occurred in those dosed with 10 μg/kg, while no changes were found in the two higher-dosed female groups in comparison to controls. A significant negative correlation was observed between hepatic P4501A indices and gonad somatic indexes values and plasma estradiol concentrations. The PCB 126 administration produced alterations in concentrations of plasma sex hormones in females but not in males. The in vitro steroidogenic potential of the female and male gonads was not affected by the in vivo PCB 126 treatment.
Relationships between acute sediment toxicity in laboratory tests and abundance and diversity of benthic infauna in marine sediments: A review
Authors: Long Edward R , Hong Carolyn B , Severn Corinne G 
Published: March 2010

AbstractAutesedimenttoxicity testshave become important in regulatory, monitoring, and scientificprograms, partly because it has been assumed that they are indicative of ecological damage to benthic infaunal resources. Data from tests of sediment toxicity and measures of benthic community structure were examined from &gt; 1,400 saltwater samples to determine the relationships between acute toxicity and changes in the abundance and diversity of infauna resources. Data were compiled from studies conducted along portions of the Atlantic, Gulf of Mexico, and Pacific coasts of the United States. There was considerable variability among the data sets in the relationships between laboratory results and benthic measures. However, in 92% of the samples classified as toxic, at least one measure of benthic diversity or abundance was &lt;50% of the average reference value. In 67% of these samples, at least one measure of benthic infauna abundance or diversity was &lt;10% of average reference conditions. No amphipods were found in 39% of samples that were classified as toxic, whereas amphipods were absent from 28% of the nontoxic samples. In many survey areas, the abundance of crustaceans (notably the amphipods) decreased in the infauna as amphipod survival decreased in the laboratory tests. There appeared to be a break point in the data indicating that, generally, amphipod abundance in the field was lowest when survival in the laboratory tests dropped below 50% of controls. Based on the weight of evidence from all the data analyses, we conclude that ecologically relevant losses in the abundance and diversity of the benthic infauna frequently corresponded with reduced amphipod survival in the laboratory tests.
Use of plants for toxicity assessment of estuarine ecosystems
Authors: Lytle Julia S , Lytle Thomas F 
Published: March 2010

AbstractEstuarine ecosystems are being rapidly degraded by environmental toxicants from municipal and industrial wastes, agricultural runoff, recreational boating, shipping, and coastal development, ranking them as the most anthropogenically degraded habitat types on earth. Toxicity tests are used to establish links between adverse ecological effects and the toxicity of environmental chemicals. However, most toxicity tests used for regulating the release of chemicals into the environment have used animals as test species, with the erroneous assumption that toxicant levels protective of fish or invertebrates are also protective of plants. Most plant toxicity tests have used terrestrial crop plants, whereas the few aquatic test species used have been primarily freshwater algae. Even though estuarine and marine vascular plants are highly vulnerable to environmental chemicals, phytotoxicity studies using native coastal plants have been limited, and no such studies are required for testing by regulating agencies. The relevance of toxicity tests of estuarine sediments and of wastes entering the estuary should depend on the use of estuarine and marine plant species. This review summarizes toxicity testing of marine plants used in biomonitoring, phytotoxicity, biotransformations of toxicants, bioaccumulation, and phytoremediation. Challenges to marine plant testing are discussed and include developing standard test protocols, identifying species with minimal salinity and toxicant interaction, defining and choosing a suitable sediment for sediment-bound toxicant testing, selecting endpoints with low variability, producing viable seeds, and culturing test plants. Progress in acquiring a suitable database is being made, but at a rate that is inadequate to create the sound, scientific foundation needed for safeguarding our estuarine ecosystems in the near future.
U.S. environmental law statutes in coastal zone protection
Authors: Rand Gary M , Carriger John F 
Published: March 2010

Abstract
U.S. federal legislation relevant to the coastal zone and adjacent ocean was reviewed and included the Coastal Zone Management Act, Clean Water Act, Marine Protection Research and Sanctuaries Act, and Oil Pollution Act. Problems affecting these waters involve complex activities/issues related to multimedia sources of pollution and coastal land use planning. Effective pollution control requires state-local-federal interaction with a better understanding of scientific as well as social and economic issues.
Cd, Cu, Pb, and Zn coprecipitates in Fe oxide formed at different pH: Aging effects on metal solubility and extractability by citrate
Authors: Martínez Carmen Enid , McBride Murray B 
Published: March 2010

Abstract
Coprecipitates of heavy metals with Fe oxides may form in contaminated soil, water, and sediment systems, particularly when oxidation-reduction processes are occurring. Once formed, coprecipitates with ferrihydrite could limit heavy metal mobility, solubility, toxicity, and bioavailability in geochemical systems. In this study, Cd, Cu, Pb, and Zn were coprecipitated with Fe by titration to pHs 6 and 7. Metal solubility was monitored during the coprecipitation process to pH 7 and after aging of the product. In the coprecipitate formed at pH 6, metal solubility was determined after the system reached pH 6 and at subsequent time intervals. We also reacted the coprecipitates with citrate and evaluated potential metal availability at increased aging times. The pH of coprecipitate formation had little effect on the long-term solubility of Cu and Zn, whereas soluble Cd was greater in the coprecipitate formed at pH 6. Soluble percentages of metals were low at both pH 6 and 7 for Cu and Pb but averaged 1.5 to 3% for Zn and greater than 40% for Cd. Hysteresis was observed in the coprecipitation curves for Zn and Cd, revealing reduced solubility after adsorption or coprecipitation. Lead and Cu failed to show hysteresis, with strong retention in the solid phase at pH greater than 6. The citrate-extractable fraction was greatest for Cd and Zn, less for Cu, and least for Pb. Citrate-extractable metal was higher for the coprecipitate formed at pH 7 than at pH 6, suggesting increased potential availability from coprecipitates formed at higher pH.
Solubilities and surface activities of phthalates investigated by surface tension measurements
Authors: Thomsen Marianne , Carlsen Lars , Hvidt Søren 
Published: March 2010

AbstractAueous solutions of DEP (di-ethyl), DnBP (di- n-butyl), DnH(6)P (di-n-hexyl), and DEHP (di-[2-ethyl-hexyl])phthalates have been investigated by use of surface tension measurements at temperatures between 10 and 35°C. A tensiometric approach allows for the determination of unimeric solubilities and ΔG°, which is the standard Gibbs free energy change, for the dissolution of phthalates in water. The unimeric solubility of the phthalates increase with decreasing temperature. The ΔG° shows a linear increase with increasing phthalate alkyl chain length. The contribution of enthalpy (ΔH°) and entropy (ΔS°) to ΔG° were calculated from the temperature-dependent solubilities. The contributions of both ΔH° and ΔS° are negative and increase in magnitude with increasing alkyl chain length, suggesting hydrophobic interactions between phthalates and water. The ability of different phthalates to lower the surface tension decreases with increasing alkyl chain length, whereas the relative affinity for adsorption in the air-water interface increases drastically for long-chain phthalates. Despite the low surface activity of phthalates compared with that of common surfactants, they show significant affinity for adsorption in air-water interfaces of natural surface waters. This property, combined with their low solubilities, may affect the fate of these compounds within the natural environment, because they form emulsions above unimeric saturation in aqueous media.
Quantification of metallothionein isoforms in fish liver and its implications for biomonitoring
Authors: Lacorn Markus , Lahrssen Angelika , Rotzoll Nina , Simat Thomas J , Steinhart Hans 
Published: March 2010

Abstract
A rapid, reproducible, and sensitive ion-exchange chromatography (IEC) method combined with graphite-furnace atomic absorption spectrometry (GF-AAS) was developed to separate and quantify basal amounts of both metallothionein (MT) isoforms in dab (Limanda limanda) liver samples. Dab liver homogenates were saturated with Cd, and obtained cytosols were purified by a two-step acetone precipitation prior to chromatographic analysis. Metallothionein isoforms were separated by IEC and were subsequently quantified indirectly by GF-AAS via their Cd contents. The amount of Cd needed for saturation was optimized. The efficiency of Cd saturation and acetone precipitation was proven by gel permeation chromatography (GPC) and metal distribution analysis. Based on the method of standard addition, a recovery for MT was 98% after acetone precipitation and 68% after IEC. The repeated determination of MT isoforms in a dab liver homogenate resulted in coefficients of variation of approximately 12% for both isoforms. Based on the detection limit for GF-AAS, the calculated detection limit for MT isoforms is 2 ng/mg protein. Therefore, this method is suitable for monitoring purposes. The implications of isoform-specific measurement for biomarker monitoring are discussed.
Development of flow cytometry-based algal bioassays for assessing toxicity of copper in natural waters
Authors: Franklin Natasha M. , Stauber Jennifer L , Lim Richard P 
Published: March 2010

AbstractCopper toxicity to the freshwater algae Selenastrum capricornutum and Chlorella sp. and the marine algae Phaeodac-tylum tricornutum and Dunaliella tertiolecta was investigated using different parameters measured by flow cytometry: cell division rate inhibition, chlorophyll a fluorescence, cell size (i.e., light-scattering), and enzyme activity. These parameters were assessed regarding their usefulness as alternative endpoints for acute (1–24 h) and chronic (48–72 h) toxicity tests. At copper concentrations of 10 μg/L or less, significant inhibition (50%) of the cell division rate was observed after 48- and 72-h exposures for Chlorella sp., S. capricornutum, and P. tricornutum. Bioassays based on increases in algal cell size were also sensitive for Chlorella sp. and P. tricornutum. Copper caused both chlorophyll a fluorescence stimulation (48-h EC50 of 10 ± 1 μg Cu/L for P. tricornutum) and inhibition (48-h EC50 of 14 ± 6 μg Cu/L for S. capricornutum). For acute toxicity over short exposure periods, esterase activity in S. capricornutum using fluorescein diacetate offered a rapid alternative (3-h EC50 of 90 ± 40 μg Cu/L) to growth inhibition tests for monitoring copper toxicity in mine-impacted waters. For all the effect parameters measured, D. tertiolecta was tolerant to copper at concentrations up to its solubility limit in seawater. These results demonstrate that flow cytometry is a useful technique for toxicity testing with microalgae and provide additional information regarding the general mode of action of copper (II) to algal species.
Effects of malathion on survival, growth, development, and equilibrium posture of bullfrog tadpoles (Rana catesbeiana)
Authors: Fordham Carolyn L , Tessari John D , Ramsdell Howard S , Keefe Thomas J 
Published: March 2010

Abstract
Bullfrog (Rana catesbeiana) tadpoles were exposed to malathion in water in a 28-d static renewal test. The effects of malathion on survival, growth, development, and loss of equilibrium posture were determined. Survival was significantly decreased at malathion concentrations of 2,500 μg/L and higher. Development of tadpoles was delayed significantly by malathion exposure as indicated by a dose-related decrease in developmental stage over time. Development of tadpoles in the 1,000-μg/L and higher treatment groups was significantly delayed from that observed in the control. The effects of malathion on developmental stage suggest that malathion may decrease thyroid function in tadpoles, as it does in other species. Maintenance of equilibrium posture following agitation of the test containers was significantly impaired in tadpoles in all the malathion treatment groups (500 to 3,000 μg/L) relative to the control. Maintenance of equilibrium posture was thus the most sensitive end point measured in this study. Loss of equilibrium posture could increase predation losses and decrease feeding in populations of bullfrog tadpoles in the field. However, concentrations of malathion that produced adverse effects in our study are higher than published, measured concentrations found in wetlands or streams.
Congener-specific model for polychlorinated biphenyl effects on otter (Lutra lutra) and associated sediment quality criteria
Authors: Traas Theo P , Luttik Robert , Klepper Olivier , Beurskens Jacobus E M , Smit Maarten D , Leonards Pim E G , van Hattum Albertus G M , Aldenberg Tom 
Published: March 2010

AbstractA model for risk assessment was built for simultaneous, congener-specific PCB bioaccumulation from sediment to fish to otters (Lutra lutra). Toxic equivalence factors (TEFs) were used to sum individual congeners in otters to a toxic equivalent concentration (TEQ) relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Microbial dechlorination and burial in sediments and bioac-cumulation are modeled to predict time trends of PCB concentrations in otters. Effects of accumulated PCBs on otters were assessed for vitamin A metabolism and reproduction, taking model uncertainty into account. Three locations in The Netherlands were modeled with PCB levels in sediment of 1 to 171 pg TEQ/g organic carbon (OC). Almost 100% reduction in litter size was predicted for the most polluted area in 1996. Due to large associated uncertainty, a period of 25 to 80 years may be needed for recovery of otter vitamin A levels and litter size at this site. Calculated median sediment quality criteria (SQC) range between 1 and 12 pg TEQ/g OC, depending on the chosen effect criterion. Uncertainty in calculated effects and SQCs is substantial and is mainly caused by uncertainty in PCB congener 126 accumulation.
Acute toxicity of (chloro-)catechols and (chloro-)catechol-copper combinations inEscherichia colicorresponds to their membrane toxicity in vitro
Authors: Schweigert Nina , Hunziker René W. , Escher, Beate I , Eggen Rik I L 
Published: March 2010

Abstract(Chloro-)catechols are toxic for bacteria and higher organisms, but the mode of action is not yet clearly understood. We have compared the acute toxicity of different chlorinated catechols to Escherichia coli with membrane toxic effects, namely narcosis and uncoupling that we have determined in an in vitro assay. In vitro membrane toxicity was quantified by measuring the accelerated decay of the membrane potential of chromatophores isolated from Rhodobacter sphaeroides. Both acute and membrane toxicity increased with increasing degree of chlorination. Analysis of dose-response curves, pH dependence, and estimated membrane concentrations gave a consistent picture of the mechanisms of membrane toxicity: At pH 7, the higher-chlorinated catechols acted as uncouplers of oxidative and photophosphorylation, and the lower-chlorinated catechols and catechol acted as narcotics. In the case of 3,5-dichlorocatechol and 4-monochlorocatechol at pH 8.8, both mechanisms appeared to contribute to the overall toxicity. Copper exhibited a diverging effect on the toxicity of catechols and of (chloro-)catechols to E. coli. Whereas the presence of copper increased the toxicity of catechol and 4-monochlorocatechol, the toxicity of 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol decreased. Again, the results obtained with in vitro assays agreed with the acute toxicity observed in E. coli: The presence of copper accelerated decay of the membrane potential of catechol and 4-monochlorocatechol; however, the effect was reversed by copper in experiments with 3,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol. We have proposed a mechanistic model to explain the diverging effects of copper on the uncoupling activities of the different catechols.
Estrogenic potency of chemicals detected in sewage treatment plant effluents as determined by in vivo assays with Japanese medaka (Oryzias latipes)
Authors: Metcalfe Chris D , Metcalfe Tracy L , Kiparissis Yiannis , Koenig Brenda G , Khan Colin , Hughes Richard J , Croley Timothy R , March Raymond E , Potter Thomas 
Published: March 2010

Abstract
Gonadal intersex and high prevalences of the female phenotype have been observed in fish populations in urbanized areas. Environmental estrogens discharged in sewage treatment plant effluents may be responsible for feminization of fish but many compounds with the potential to induce these responses occur in effluents, including natural and synthetic estrogen hormones, degradation products of alkylphenol ethoxylate surfactants, and plasticizers. In this study, the estrogen hormones 17α-ethinylestradiol, 17β-estradiol, estrone, and estriol induced intersex (i.e., testis-ova) and altered sex in Japanese medaka (Oryzias latipes) when these fish were exposed to nanogram per liter concentrations of test compounds from hatch to approximately 100 d after hatch. A mix of nonylphenol mono- and diethoxylate induced a weak response and a mix of nonylphenol mono- and diethoxycarboxylate did not give a response in this assay at microgram per liter concentrations, indicating that these degradation products of nonylphenol ethoxylates have little or no estrogenic activity in fish. Bisphenol A induced testis-ova in medaka exposed to a concentration of 10 μg/L, but diethylhexyl phthalate did not induce a response. Results with the medaka assay were consistent with estrogenic responses in the yeast estrogen screening assay. Analyses of monitoring data reported in the literature indicate that concentrations of estrogen hormones detected in the final effluents of sewage treatment plants are generally greater than the lowest-observed-effect levels for alterations to gonadal development in medaka.
Accumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin by rainbow trout (Onchorhynchus mykiss) at environmentally relevant dietary concentrations
Authors: Jones, Paul D , Kannan Kurunthachalam , Newsted John I , Tillitt Donald E , Williams Lisa L , Giesy John P 
Published: March 2010

AbstractRainbow trout were fed a diet containing 1.8, 18, or 90 pg/g 3H-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for up to 320 d. Concentrations of TCDD were determined in muscle, liver, and ovaries at 100, 150, 200, and 250 d. Concentrations of TCDD reached an apparent steady-state concentration in liver after 100 d of exposure, whereas concentrations in other tissues continued to increase until 150 d of exposure. The greatest portion of the total mass of TCDD was present in the muscle tissue with lesser proportions in other organs. As the ovaries developed before spawning, an increase occurred in the total mass of TCDD present in this tissue. The assimilation rate of TCDD during the initial 100 d of the exposure was determined to be between 10 and 30%. This is somewhat less than estimates derived based on both uptake and elimination constants determined during shorter exposures. Biomagnification factors (BMFs) were estimated for all tissues and exposure concentrations, and at all exposure periods. Lipid-normalized BMFs for muscle ranged from 0.38 to 1.51, which is consistent with the value of 1.0 predicted from fugacity theory. Uptake and depuration rate constants were determined and used to predict individual organ TCDD concentrations. Comparison with observed values indicated that the model could be used to predict tissue concentrations from the known concentrations of TCDD in food. This model will allow more refined risk assessments by predicting TCDD concentrations in sensitive tissues such as developing eggs.