bluuebunny/crossref_metadata_2025_split huggingface dataset:
Avoidance response of the estuarine amphipodEohaustorius estuariusto polycyclic aromatic hydrocarbon-contaminated, field-collected sediments
Authors: Kravitz Michael J , Lamberson Janet O , Ferraro Steven P , Swartz Richard C , Boese Bruce L , Specht David T 
Published: March 2010

AbstractAmphipods (Eohaustorius estuarius) were placed in two-chamber containers with different combinations of three contaminated sediments and a control sediment, and their distribution was determined after 2 or 3 d. Amphipods avoided the sediment with the highest PAH contamination and one of two sediments with moderate PAH concentrations. In the moderately contaminated sediment avoided by amphipods, the (avoidance) response was more sensitive than mortality as a biological indicator of unacceptable sediment contamination (over the 2–3-d exposure). The avoidance response in this case likely represents an early indication of potential mortality from sediment exposure. Population levels of amphipods in moderately to heavily PAH-contaminated sediments may be influenced by a combination of avoidance behavior and toxicity/lethality.
Fish mercury distribution in Massachusetts, USA lakes
Authors: Rose Jane , Hutcheson Michael S , West Carol Rowan , Pancorbo Oscar , Hulme Kenneth , Cooperman Al , Decesare Gregory , Isaac Russell , Screpetis Arthur 
Published: March 2010

Abstract
The sediment, water, and three species of fish from 24 of Massachusetts' (relatively) least-impacted water bodies were sampled to determine the patterns of variation in edible tissue mercury concentrations and the relationships of these patterns to characteristics of the water, sediment, and water bodies (lake, wetland, and watershed areas). Sampling was apportioned among three different ecological subregions and among lakes of differing trophic status. We sought to partition the variance to discover if these broadly defined concepts are suitable predictors of mercury levels in fish. Average muscle mercury concentrations were 0.15 mg/kg wet weight in the bottom-feeding brown bullheads (Ameiurus nebulosus) (range = 0.01–0.79 mg/kg); 0.31 mg/kg in the omnivorous yellow perch (Perca flavescens) (range = 0.01–0.75 mg/kg); and 0.39 mg/kg in the predaceous largemouth bass (Micropterus salmoides) (range = 0.05–1.1 mg/kg). Statistically significant differences in fish mercury concentrations between ecological subregions in Massachusetts, USA, existed only in yellow perch. The productivity level of the lakes (as deduced from Carlson's Trophic Status Index) was not a strong predictor of tissue mercury concentrations in any species. pH was a highly (inversely) correlated environmental variable with yellow perch and brown bullhead tissue mercury. Largemouth bass tissue mercury concentrations were most highly correlated with the weight of the fish (+), lake size (+), and source area sizes (+). Properties of individual lakes appear more important for determining fish tissue mercury concentrations than do small-scale ecoregional differences. Species that show major mercury variation with size or trophic level may not be good choices for use in evaluating the importance of environmental variables.
Influence of sediment-organic matter quality on growth and polychlorobiphenyl bioavailability in Echinodermata (Amphiura filiformis)
Authors: Gunnarsson Jonas S , Granberg Maria E , Nilsson Hans C , Rosenberg Rutger , Hellman Birthe 
Published: March 2010

AbstractSediment total organic carbon (TOC) content is considered to be a primary food source for benthic invertebrates and a major factor influencing the partitioning and bioavailability of sediment-associated organic contaminants. Most studies report that both toxicity and uptake of sediment-associated contaminants by benthic organisms are inversely proportional to sediment TOC content. The aim of this study was to determine the importance of the TOC quality for the bioavailability of sediment-associated organic contaminants and the growth of benthic macrofauna. The common infaunal brittle star Amphiura filiformis was exposed to a base sediment covered by a 14C-polychlorobiphenyl(3,3′4,4′-14C-tetrachloiphenyl (TCB)) contaminated top layer (0−2 cm), enriched to the same TOC content with 31 g TOC/m2 of different quality and origin. The following carbon sources, ranging from labile to refractory, were used: (1) green macroalga (Ulva lactuca), (2) brown macroalga (Ascophyllum nodosum), (3) eelgrass (Zostera marina), (4) phytoplankton (Ceratium spp.), and (5) lignins of terrestrial origin. Characterization of the organic matter quality was accomplished by measuring the content of amino acids, lipids, C, N, and polyphenolic compounds. The reactivity of the sedimentary organic matter was assessed by means of respiration and dissolved inorganic nitrogen flux measurements. The experiment was carried out in 1-L glass jars, each containing four brittle stars and the contaminated and enriched sediment. The jars were circulated in a flow-through mode with filtered seawater. Somatic growth (regeneration of a precut arm) and bioaccumulation of 14C-TCB were measured at 10 sampling occasions during 48 d of exposure. Growth rates, TCB uptake rates, and steady-state concentrations differed significantly between treatments and were correlated to the qualities of the organic substrates. The greatest TCB accumulation and growth were observed in treatments with the most labile organic substrates and the lowest accumulation and growth were seen with the most refractory substrates. Results from this experiment suggest that the bioaccumulation of organic contaminants in benthic infauna is dependent on the nutritional quality of the sedimentary organic matter.
Mechanisms for adsorption of organic bases on hydrated smectite surfaces
Authors: Laird David A , Fleming Pierce D 
Published: March 2010

Abstract
Mechanisms by which organic bases are adsorbed on hydrated smectite surfaces were investigated. Three Ca-saturated reference smectites (Otay, SPV, and Panther Creek) were dispersed in distilled water containing 5 μmol of pyridine or 3-butylpyridine. The pH was adjusted to between 7.5 and 3 using 0.01 M HCl. After a 2-h equilibration, the amount of pyridine or 3-butylpyridine adsorbed on the clay and the amount of Ca desorbed from the clay were determined. Negligible amounts of pyridine were adsorbed by the Ca-smectites in the neutral systems (pH &gt; 7); however, most of the added pyridine was adsorbed on the smectites in the acidified systems (pH &lt; 5). Equivalent amounts of Ca2+ were desorbed from the clays, indicating that pyridine was adsorbed as a protonated species by cation exchange. By contrast, 40 to 90% of added 3-butylpyridine was adsorbed on the smectites at neutral pHs, whereas only small amounts of Ca2+ were desorbed. The results suggest that 3-butylpyridine is initially retained by hydrophobic bonding between the alkyl side chain of the molecule and hydrophobic nanosites located between the charge sites on smectite surfaces. Surface acidity catalyzed protonation 1 to 1.5 pH units above the pKa of the bases.
Prediction of biodegradability from chemical structure: Modeling of ready biodegradation test data
Authors: Loonen Hélène , Lindgren Fredrik , Hansen Bjørn , Karcher Walter , Niemelä Jay , Hiromatsu Koichi , Takatsuki Mineo , Peijnenburg Willie , Rorije Emiel , Struijś Jaap 
Published: March 2010

AbstractBiodegradation data were collected and evaluated for 894 substances with widely varying chemical structures. All data were determined according to the Japanese Ministry of International Trade and Industry (MITI) I test protocol. The MITI I test is a screening test for ready biodegradability and has been described by Organization for Economic Cooperation and Development (OECD) test guideline 301 C and European Union (EU) test guideline C4F. The chemicals were characterized by a set of 127 predefined structural fragments. This data set was used to develop a model for the prediction of the biodegradability of chemicals under standardized OECD and EU ready biodegradation test conditions. Partial least squares (PLS) discriminant analysis was used for the model development. The model was evaluated by means of internal cross-validation and repeated external validation. The importance of various structural fragments and fragment interactions was investigated. The most important fragments include the presence of a long alkyl chain; hydroxy, ester, and acid groups (enhancing biodegradation); and the presence of one or more aromatic rings and halogen substituents (retarding biodegradation). More than 85% of the model predictions were correct for using the complete data set. The not readily biodegradable predictions were slightly better than the readily biodegradable predictions (86 vs 84%). The average percentage of correct predictions from four external validation studies was 83%. Model optimization by including fragment interactions improved the model predicting capabilities to 89%. It can be concluded that the PLS model provides predictions of high reliability for a diverse range of chemical structures. The predictions conform to the concept of readily biodegradable (or not readily biodegradable) as defined by OECD and EU test guidelines.
Degradation of linear alkylbenzene sulfonate in soil columns
Authors: Branner Ulla , Mygind Merete , Jørgensen Claus 
Published: March 2010

Abstract
This study investigated the ability of a microbial community to degrade linear alkylbenzene sulfonate (LAS) in soil columns under water-saturated conditions. The microbial mineralization of LAS was further studied in a batch experiment using pre-exposed and unexposed soil as well as soil from the inlet and outlet of the columns. The LAS (4 mg/L) was added continuously to the columns. Three pulses of 14C-labeled LAS (14C-dodecyl-[6]-benzene sulfonate) were added at intervals of 2 weeks, and the mineralization was measured as production of 14CO2. The primary degradation of LAS was close to 100% in the columns, whereas the mineralization of the 14C-labeled compound reached only 9%. The degradation products of LAS proved to be significantly less sorbtive than LAS itself. In the batch experiment, mineralization of LAS occurred in unexposed soil after a short lag phase. The mineralization proved to be more dependent on a high representation of biomass than on previous exposure to LAS.
Effects of exposure to azaarenes on emergence and mouthpart development in the midgeChironomus riparius(Diptera: Chironomidae)
Authors: Bleeker Eric A.J , Leslie Heather A , Groenendijk Dick , Plans Marc , Admiraal Wim 
Published: March 2010

AbstractAdverse effects of azaarenes on emergence and mouthpart development of the midge Chironomus riparius were analyzed using six closely related three-ringed isomers and metabolites. Effects on growth rate were examined by comparing the average day of emergence of exposed midges with that of controls. Fluctuating asymmetry (FA) in the pecten epipharyngis was examined as a measure of developmental abnormality. Delayed emergence was found at concentrations as low as 2% of the acute LC50, so emergence day appears to be a useful sensitive parameter to quantify life cycle effects. No differences in FA were found between exposed and control larvae, although, in other studies, all compounds have been proven to be genotoxic. The differences in the genotoxic and FA-inducing properties of these compounds indicate that different mechanisms are involved in expressing these adverse effects. This study also illustrates that the choice of the morphological parameter strongly influences the results of developmental disturbance analyses and thus the risk qualification of a potentially hazardous compound.
Assessing model uncertainty for environmental decision making: A case study of the coherence of independently derived environmental quality objectives for air and water
Authors: Ragas Ad M.J , Etienne Rampal S , Willemsen Frank H , Van De Meent Dik 
Published: March 2010

AbstractMany decisions in environmental management are based on model predictions that are plagued by uncertainty. It is sensible to consider this uncertainty because it can influence the outcome of the decision-making process. This paper outlines a method to assess uncertainty in model predictions in situations in which validation research is difficult or impossible. It is illustrated in a case study of the coherence of independently derived environmental quality objectives (EQOs) for air and water involving the application of a multimedia fate model (SimpleBox). Distinction was made between operational and fundamental uncertainty, which were assessed separately. Operational uncertainty was assessed by quantifying the uncertainties in the input parameters of the model and performing Monte Carlo simulations. Fundamental uncertainty was assessed tentatively by means of a postal questionnaire among scientists and scientifically trained policy makers and representatives of interest groups in the Netherlands. The results indicate that the perceived fundamental uncertainty tends to exceed the calculated operational uncertainty. These results emphasize the importance of considering fundamental uncertainty in environmental decision making. Efforts to improve the quality of coherence testing of independently derived EQOs should aim at reducing the perceived fundamental uncertainty, for example, by defining the coherence criteria of EQOs in measurable attributes, thus facilitating validation research and enabling a more detailed assessment of the fundamental uncertainty.
Liposome—water and octanol—water partitioning of alcohol ethoxylates
Authors: Muuller Markus T , Zehnder Alexander JB , Escher Beate I 
Published: March 2010

AbstractLiposome—water partitioning coefficients, (Klipws), were determined for eight pure alcohol ethoxylates using equilibrium dialysis and ultracentrifugation. Both methods yielded statistically indistinguishable results. The experimentally determined log Klipws were compared with log Kow values estimated with the fragment method using different literature sources for the fragment constants. Fragments of log Klipw were calculated for the ethoxy group (EO) and the -CH2- units from the experimentally determined data. An additional -CH2- unit causes an average increase of log Klipw by 0.45, and an additional EO causes an average decrease of log Klipw by −0.12. With these fragments, the quality of log Klipw estimations can be improved significantly as compared to simple linear regression of log Klipw versus log Kow. The Klipw values calculated according to the new fragment method for pure compounds and for commercial mixtures are shown to be adequate descriptors for quantitative structure—activity relationships of bioaccumulation, toxicity, and sorption to natural organic material.
Optimization of the methylene blue assay for anionic surfactants added to estuarine and marine water
Authors: George Alison L , White Graham F 
Published: March 2010

Abstract
The existing rapid method for the determination of anionic surfactants in aqueous solutions relies on the association of the cationic methylene blue dye with the anionic surfactant to form an electroneutral complex that is subsequently extracted into chloroform and determined spectrophotometrically. This methylene blue active substance (MBAS) assay suffers from salt interference in estuarine and marine waters due to the high concentration of chloride (Cl-) ions. The interference was shown to arise from the association of Cl- ions with the cationic methylene blue dye, which, although weak, becomes significant at the elevated concentrations of Cl- in marine water. Analysis of the kinetics of the formation and extraction into chloroform of complexes of methylene blue with a typical anionic surfactant (sodium dodecyl sulfate, SDS) and with Cl- ions revealed that the efficacy of the extraction step was critical in yielding reliable data. Based on these results, a modified, simple one—step MBAS method is described that overcomes interference by salt.
Modulation of CYP1A expression in rainbow trout by a technical grade formulation of propiconazole
Authors: Levine Steven L , Oris James T , Denison Michael S 
Published: March 2010

AbstractIn a recent survey of pesticide concentrations in aquatic ecosystems of Central America, the antifungal triazole compound propiconazole was found to be the most widely distributed pesticide. Previously, technical grade propiconazole (TGP) has been shown to modulate cytochrome P450 activity in mammals and birds. The present study investigated the concentration- and timedependent effects of TGP on hepatic cytochrome CYP1A gene expression and catalytic activity in rainbow trout (Oncorhyncus mykiss). The TGP produced both a mixed-pattern response and a biphasic response for CYP1A expression following waterborne exposure. Evidence for inhibitory complex formation with cytochrome P450 may explain the occurrence of the mixed-pattern response. To further characterize the influence of TGP on CYP1A expression, a comparison was made between TGP and analytical grade propiconazole (AGP) with in vivo and in vitro assays. This comparison demonstrated that induction of the CYP1A gene resulted from unidentified compounds in TGP. Since TGP can be coapplied with other agricultural pesticides, either inhibition or induction of CYP1A protein activity by TGP and potentially other cytochrome P450 isoenzymes may lead to unexpected toxicological interactions.
Acute and chronic bioassays with New Zealand freshwater copepods using pentachlorophenol
Authors: Willis Kate J 
Published: March 2010

AbstractThe suitability for laboratory culture and comparative sensitivity of three species of New Zealand freshwater copepod (Calamoecia lucasi Brady, Boeckella delicata Percival, and Mesocyclops cf. leuckarti Claus) to pentachlorophenol (PCP) was assessed. Acute bioassays used two life stages (nauplii and adults). Acute 48-h lethality tests were conducted at 22°C with laboratorycultured animals of all species and at varying temperatures with seasonally collected C. lucasi adults. Mean 48-h median lethal concentration values for nauplii ranged from 52 to 227 μg/L PCP for C. lucasi and B. delicata, respectively, and from 106 to 173 μg/L for adult C. lucasi and M. leuckarti, respectively. The survival rate in controls was ≥95% in acute tests, with the exception of C. lucasi nauplii, in which it was 60%. Mean 48-h median lethal concentration values for seasonally collected C. lucasi adults were significantly higher in summer than in all other seasons. Chronic sublethal tests starting with nauplii &lt;24 h old measured time to metamorphosis. Pentachlorophenol delayed metamorphosis in all species. Chronic toxicity values were 14, 61, and 104 μg/L PCP for C. lucasi, B. delicata, and M. leuckarti, respectively. The mortality rate in controls was also high in C. lucasi sublethal tests (65%), and of the three species, they were the most difficult to culture.
Bioaccumulation tests applied in whole effluent assessment: A review
Authors: de Maagd P Gert-Jan 
Published: March 2010

AbstractUntil recently, the emphasis within whole effluent assessment has been on the application of bioassays for acute and chronic toxicity. Although the need for additional parameters to assess the ecotoxicological hazard and risk of effluents for receiving water systems has been repeatedly advocated, other parameters such as bioaccumulation, genotoxicity, sediment toxicity, and nutrient impacts are seldom addressed. This paper discusses the potential additional value of including bioaccumulation parameters in whole effluent assessment and methods that can be used for routine assessment. It is concluded that screening on the presence of potentially bioaccumulating compounds leads to a more comprehensive hazard assessment and should therefore be included in whole effluent assessment. A chemical method to assess potentially bioaccumulating substances (PBSs) is preferred above methods using organisms or classical group parameters such as extractable organic halogens (EOX). In situ studies with organisms are not feasible for routine assessment for a number of reasons, including cost efficiency and matrix problems. Classical group parameters such as EOX do not relate to bioaccumulation or toxicity. Chemical methods for assessing bioaccumulation are usually presented as integrated methods composed of different procedure steps such as pretreatment, extraction, separation, and detection. However, an optimal method may be constructed by combining procedure steps from different reported methods. Solid phase microextraction combined with high performance liquid chromatography or gas chromatography combined with mass spectrometry is regarded as the preferable method for the assessment of PBSs. Before implementation in whole effluent assessment, however, the method must be carefully validated. Hazard assessment based on bioaccumulation seems feasible. For risk assessment, however, additional information is a prerequisite. Quantitative causal relationships between test assay results and relevant effects on the population and ecosystem level are absent, hampering the desired upgrading from hazard to risk assessment.
Effect of soil contaminant extraction method in determining toxicity using the microtox® assay
Authors: Harkey Gail A , Young Thomas M 
Published: March 2010

AbstractThis project examined the influence of different extraction methods onthe measured toxicityofcontaminatedsoils collected from manufactured gas plant (MGP) sites differing in soil composition and contaminant concentration. Aged soils from a number of MGP sites were extracted using a saline solution, supercritical fluid extraction (SFE), and Soxhlet extraction. Toxicity was assessed using two forms of Microtox® tests: acute aqueous tests on saline and SFE soil extracts and solid-phase tests (SPTs) on soil particles. Microtox SPTs were performed on soils before and after SFE to determine resulting toxicity reduction. Three hypotheses were tested: (1) Toxicity of soil extracts is related to contaminant concentrations of the extracts, (2) measured toxicity significantly decreases with less vigorous methods of extraction, and (3) supercritical fluid extractability correlates with measured toxicity. The EC50s for SPTs performed before and after SFE were not different for some soils but were significantly greater after extraction for other soils tested. The most significant toxicity reductions were observed for soils exhibiting the highest toxicity in both preextraction SPTs and acute aqueous tests. Acute Microtox tests performed on SFE extracts showed significantly lower EC50s than those reported from saline-based extraction procedures. Toxicity of the soils measured by Microtox SPTs was strongly correlated with both SFE efficiency and measures of contaminant aging. Data from this project provide evidence of sequestration and reduced availability of polycyclic aromatic hydrocarbons (PAHs) from soils extracted via physiologically based procedures compared to vigorous physical extraction protocols.