bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear alkylbenzenesulfonate (LAS) surfactants in a simple test to detect refractory organic carbon (ROC): Attribution of recalcitrants to impurities in LAS
Authors: Kölbener Pius , Baumann Urs , Leisinger Thomas , Cook Alasdair M. 
Published: March 2010

Abstract
The standard procedure to examine the biodegradability of a (group of) compound(s) in a trickling filter is a continuous-flow system. In this test, nondegraded metabolites from a commercial linear alkylbenzenesulfonate (LAS) surfactant are detected (Kölbener, Baumann, Leisinger, and Cook; accompanying paper). This procedure has now been augmented by two phases in closed cycle to give a test for refractory organic carbon (ROC test). First, the concentration of nondegraded metabolites was increased by readdition of LAS to the solution being cycled through the filter. Second, the concentrated residues were further recycled till the net dissolved organic carbon (DOC) stabilised at a finite value and the net released CO2 stabilised at about zero. The organic compounds remaining at this phase of the experiment were considered recalcitrant and could be examined by global (e.g., DOC) and specific (e.g., HPLC) assays. Four different commercial preparations of LAS were examined, as were the (4-sulfophenyl)undecane homologue (C11-LAS), the (4-sulfophenyl)dodecane homologue (C12-LAS), and some related compounds. The four commercial LAS preparations contained different levels of impurities (2% to about 17%, according to the producers), which were largely dialkyltetralinesulfonates (DATS) and branched-chain alkylbenzenesulfonates (bABS). The refractory organic carbon (ROC) remaining after biodegradation varied from 3 to 14%. The results were a characteristic of the LAS under study and were independent of the source of the biomass used in the experiment. Residues were examined by HPLC, and 50 to 100 peaks were observed, which were usually characteristic of the LAS studied. No peak has been conclusively identified. We consider the recalcitrants to represent carboxylated DATS and carboxylated bABS.
Comparisons of the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on chemically impacted and nonimpacted subpopulations of Fundulus heteroclitus: I. TCDD toxicity
Authors: Prince Ruth , Cooper Keith R. 
Published: March 2010

Abstract
A subpopulation of Fundulus heteroclitus inhabiting the chemically impacted estuary of Newark Bay, New Jersey, was found to be resistant to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as compared to a chemically non-impacted subpopulation of F. heteroclitus in Tuckerton, New Jersey. The Newark/Raritan Bay estuary is a major site of TCDD contamination. The Newark F. heteroclitus embryos, when exposed to 12 to 100 parts per trillion (pptr) [3H]TCDD/acetone (nominal water concentrations) did not exhibit TCDD-dependent lesions or death. In contrast, the Tuckerton embryos exhibited both TCDD concentration-related lesions and death that was associated with the lesions. The Newark embryonic resistance to TCDD toxicity could not be attributed to a lesser absorption of [3H]TCDD as compared to the Tuckerton embryos. The Newark F. heteroclitus adult fish, when dermally treated with 0.30 to 60 ng/g [3H]TCDD/DMSO, did not exhibit TCDD treatment-related increases in death, lesions, or liver-to-body-weight ratios, whereas the Tuckerton adult fish did. The Newark fish did exhibit greater parasitic infestations of the liver, greater hepatic neoplasias, and greater liver-to-body-weight ratios, all of which were independent of laboratory TCDD treatment, as compared to the Tuckerton fish. These hepatic effects in the Newark fish may be indicative of the chronic chemical exposure of this F. heteroclitus subpopulation.
Comparisons of the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on chemically impacted and nonimpacted subpopulations ofFundulus heteroclitus: II. metabolic considerations
Authors: Prince Ruth , Cooper Keith R. 
Published: March 2010

AbstractA previous paper reported resistance to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity in a subpopulation of Fundulus heteroclitus inhabiting the chemically impacted estuary of Newark Bay, New Jersey, as compared to a chemically nonimpacted subpopulation of F. heteroclitus in Tuckerton, New Jersey. This paper reports the results of toxicokinetic and metabolic investigations. The rates of [3H]TCDD elimination following a single dermal treatment of [3H]TCDD were similar between the Newark and Tuckerton F. heteroclitus subpopulations, as were the capabilities to metabolize TCDD. The Newark F. heteroclitus subpopulation consistently exhibited elevated hepatic P4501A catalytic activity (two- to fivefold), as measured by ethoxyresorufin O-deethylase (EROD), compared to the Tuckerton subpopulation. EROD activity in Newark F. heteroclitus could not be induced by dermally administered [3H]TCDD, ranging from 0.020 to 8.0 ng/g [3H]TCDD. The Tuckerton fish exhibited a linear increase in EROD activity at 96 h following dermal administration of [3H]TCDD, ranging from 0.80 to 8.0 ng/g [3H]TCDD. The maximum mean induction in the Tuckerton fish was 30-fold greater than the Tuckerton vehicle control mean. These data indicate that the Newark fish were resistant to both the toxicity of TCDD and the ability of TCDD to induce P4501A activity, which may imply an alteration in the Ah receptor complex of Newark F. heteroclitus.
A QSAR for steroidal compound interaction with cytochrome P4501A1
Authors: Chan Zenith , Hoixebone B. R. 
Published: March 2010

AbstractThe well-known binding and metabolism of polycyclic aromatic hydrocarbons (PAHs) by cytochrome P4501A1 has led to a proposed metabolic specialization of P4501A1 to endogenous hormones. To assess this hypothesis, the binding affinities of nine steroidal molecules of increasing multiple bond content and the aromatic compound chrysene were tested against a standard ethoxyresorufin O-deethylation assay. Both the hydrophobicity and the planarity of these molecules correlate to their binding efficiency. However, the product of these two properties shows a much stronger correlation than each separately. By using standard mathematical identities, hydrophobicity and planarity can be related to the enthalpy and entropy of activation, respectively. In this model, the hydrophobicity represents the adhesiveness per unit contact area with the active site, and the planarity the proportion of molecular structures in contact with the site. The net adhesiveness is therefore accidentally largest for the xenobiotic PAH structures.
Assessment of experimental data on PCB-induced reproduction inhibition in mink, based on an isomer- and congener-specific approach using 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalency
Authors: Leonards Pim E. G. , De Vries Theo H. , Minnaard Wim , Stuijfzand Suzanne , De Voogt Pim , Cofino Wim P. , van Straalen Nico M. , van Hattum Bert 
Published: March 2010

AbstractThis paper describes an attempt to derive a median effect level (EC50) of PCBs for reproduction of mink based on experimental literature data. Unfortunately, the conditions of the mink studies carried out during the last two decades vary widely, which makes it difficult to establish unequivocal dose-effect relationships. This study describes an attempt to correct for the differences in exposure time using a one-compartment bioaccumulation model. This model estimates the whole-body concentration of PCBs in mink. Two approaches are tested. First, the whole-body concentration of 10 isomer groups of PCBs in mink were estimated and compared with reproduction data to calculate an EC50 value. Alternatively, estimates for the whole-body concentration in mink of 11 individual biologically active PCB congeners were made. With these, the toxic equivalent concentration (TEC) in mink was estimated using the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent factor (TEF) approach. Whole-body dose-effect relationships were estimated and EC50 values for litter size and kit survival were calculated. The application of the one-compartment bioaccumulation model of the first approach resulted in a significant improvement in the dose-effect relationship in comparison to the raw data set. A further improvement in this relationship was achieved using the congener-specific bioaccumulation model in combination with the TEF approach. This study proposes a critical body residue (EC50) for mink litter size of 1.2 μg/g (total PCBs/wet weight). From the second approach a critical body residue (EC50) expressed in TCDD equivalency for litter size of 160 pg/g (TCDD equivalence/wet weight) and 200 ng/g (TCDD equivalence/wet weight) for kit survival is proposed.
Hepatic cytochrome P4501A induction in DAB (Limanda limanda) after oral dosing with the polychlorinated biphenyl mixture clophen A40
Authors: Sleiderink Hedwig M. , Everaarts Jan M. , Goksøyr Anders , Boon Jan P. 
Published: March 2010

Abstract
The flatfish dab (Limanda limanda) serves as an indicator species in pollution monitoring programmes in the North Sea. The present study investigated the induction response of the monooxygenase system and haematological changes in female dab after multiple administrations of a technical mixture of polychlorinated biphenyls (PCBs). Mature female dab were dosed with 1 mg of the PCB mixture Clophen A40 (Clo A40) in sunflower oil every 6 weeks, with a maximum of three doses per fish. In all PCB-administered groups, levels of cytochrome P4501A (CYP1A) protein, measured with a semi-quantitative ELISA method, and 7-ethoxyresorufin O-deethylase (EROD) activity showed a three- to ninefold induction 14 d after dosing compared with control groups, smaller but also significant increases were observed in total cytochrome P450 (Σ P450) levels. Although the PCB concentrations and the corresponding toxic equivalent (TEQ) value in muscle tissue still increased after administration of the second and third dose of Clo A40, maximum responses of the EROD activity were already reached after the first dose at a TEQ value for chlorinated biphenyls (CB-TEQ) of 2 ng/g lipid. The PCB patterns of liver and muscle tissue of female dab from the central North Sea were found to be virtually identical. Hence, the use of PCB concentrations in muscle as a qualitative model for changes in the liver appears legitimate. Haemoglobin concentrations were elevated after the third dose of Clo A40, whereas haematocrit values and the mean corpuscular haemoglobin concentration (MCHC) between treated and control groups did not differ.
Influence of pH on the toxicity of ammonia toChironomus tentansandLumbriculus variegatus
Authors: Schubaur-Berigan Mary K. , Monson Philip D. , West Corlis W. , Ankley Gerald T. 
Published: March 2010

AbstractThe U.S. Environmental Protection Agency water-quality criteria establish permissible levels of ammonia in the nation's fresh waters. These criteria are based on accumulated research suggesting that, for most aquatic species (primarily fishes), the toxicity of un-ionized ammonia predominates over that of the ammonium ion. The development of a sediment-quality criterion for ammonia requires evaluation of the relative toxicity of the two ammonia forms to benthic and epibenthic macroinvertebrates to determine whether the water-quality toxicity model can be applied to sediments. Flow-through ammonia toxicity tests were conducted over 10 d with the oligochaete Lumbriculus variegatus and the larval midge Chironomus tentans at four pH values (6.3, 7.2, 7.8, and 8.6) using a unique pH control system. Total ammonia was more toxic at elevated than at low pH to both species, suggesting that un-ionized ammonia (more prevalent at high pH) is important in determining the toxicity of ammonia to these two species. Hardness or alkalinity differences in the range of 30 to 200 mg/kg (as CaC03) did not appear to affect the toxicity of ammonia to the two species in separate 4-d tests. Based on results of the 10-d tests, the joint toxicity/pH model that establishes the water-quality criterion value for ammonia appears to be sufficiently protective of L. variegatus and C. tentans, by factors of at least 3 and 10, respectively. However, this study did not address potential differences in exposure of benthic organisms to ammonia in sediments vs. that in the water column; nor were the chronic effects of ammonia on these species measured in this study.
Endocrine and metabolic dysfunction in yellow perch, Perca flavescens, exposed to organic contaminants and heavy metals in the ST. Lawrence river
Authors: Hontela Alice , Dumont Pierre , Duclos Dominick , Fortin RÉJean 
Published: March 2010

Abstract
The endocrine and biochemical responses to the acute stress of capture and handling were investigated in sexually mature and in immature male and female yellow perch, Perca flavescens, from a site contaminated by organic contaminants (PAHs and PCBs) and heavy metals (Hg, Cd, As, and Zn) and from a reference site in the St. Lawrence River. Following a standardized capture and handling stress, fish from the contaminated site did not exhibit the expected physiological stress response observed in fish from the reference site. Blood Cortisol and thyroxine levels were lower, and liver glycogen stores were greater in mature males and females, as well as in the immature fish from the contaminated site, compared to the reference site. Fish from the contaminated site also had smaller gonads and lower condition factor. The impaired ability to elevate blood Cortisol in response to an acute stress may be used as a biomarker of toxic stress in health assessment of feral fish from polluted environments.
Uptake and loss of Bacillus thuringiensis var. israelensis by Daphnia magna in laboratory exposure
Authors: Vaishnav Dinesh D. , Anderson Richard L. 
Published: March 2010

Abstract
We determined the ingestion and loss of the spores of Bacillus thuringiensis var. israelensis (Bti) by a nontarget organism Daphnia magna. Daphnids were either not fed or fed during the exposure to the spores. The results showed that (a) the uptake rates with unfed and fed daphnids were approximately first-order with respect to spore concentration, and the rate constants for unfed and fed daphnids were 5.5 × 10−5 and 1.4 × 10−7 L daphnid−1 h−1, respectively, and (b) unfed and fed daphnids rapidly depurated the majority of the accumulated spores, and the depuration rate constants for unfed and fed daphnids were 0.13 and 0.15 h−1, respectively.
Equilibrium studies in natural waters: Speciation of phenolic compounds in synthetic seawater at different salinities
Authors: Gianguzza Antonio , De Stefano Concetta , Sammartano Silvio , Demianov Piotr 
Published: March 2010

Abstract
Interactions between some phenolic compounds and macro-constituents of synthetic seawater (Na+, K+, Ca2+, Mg2+, Cl−, and SO2−4), at 20, 35, and 45%0 salinity, have been investigated potentiometrically by using the [H]-glass electrode. The formation constants of phenol, o- and p-cresol, o- and p-nitrophenol complexes with sodium, potassium, calcium, and magnesium ions have been determined in the ionic strength range 0 ≤ I ≤ 1 mol/L. A comparison between the apparent protonation constants of phenols determined in synthetic seawater, and those simulated by a suitable complex formation model, is discussed. The possibility of calculating, by simulation, the apparent protonation constants of some chlorophenolic compounds in synthetic seawater is also reported.
Quantification of metallothionein as a biomarker for cadmium exposure in terrestrial gastropods
Authors: Berger Burkhard , Dallinger Reinhard , Thomaser Astrid 
Published: March 2010

Abstract
A useful cadmium saturation method, the cadmium-Chelex assay, is adopted and modified for quantification of metallothionein induction and protein cadmium saturation in midgut gland of cadmium-exposed Roman snails (Helix pomatia). The assay is based on denaturation of nonmetallothionein, cadmium-binding ligands; complete saturation of metallothionein by adding excess amounts of nonradioactive cadmium; and chelating of excessive amounts of cytosolic metal by the Chelex-100 cation exchange resin. After short-term cadmium feeding, snails quickly responded by showing rising metallothionein levels, protein concentrations in the midgut gland increasing from about 300 μg/g tissue (wet weight) to 750 μg/g within a period of 2 d. At the same time cadmium loading of protein rose form 20% in control snails to 50% saturation in exposed individuals. After long-term cadmium exposure, maximal metallothionein concentrations of about 1,000 μg/g tissue (wet weight) and a relative metallothionein cadmium saturation of 70% were reached in midgut glands of exposed snails. It is proposed that metallothionein quantification in H. pomatia might be used as a tool for biomarker studies in three ways. First, the slope of metallothionein induction might be used as a biomarker for incipient cadmium exposure and for the responsiveness of an invertebrate to metal exposure stress. Second, the steady-state level of metallothionein concentration in the midgut gland of H. pomatia might serve as an integrating biomarker reflecting single or repeated exposure events occurring over a prolonged period of time. Third, the percentage cadmium saturation of metallothionein could be utilized as a biomarker indicating if and by how much the detoxification capacity of H. pomatia is becoming exhausted due to elevated cadmium exposure.
To normalize or not to normalize? Fat is the question
Authors: Hebert Craig E. , Keenleyside Karen A. 
Published: March 2010

Abstract
Concentrations of lipophilic contaminants in biota are frequently corrected for variation in tissue lipid content. Usually, this correction is accomplished by dividing tissue contaminant concentration by lipid concentration to form lipid-normalized data. This ratio-based approach is satisfactory when contaminant concentration varies in direct proportion to lipid content. However, when such a relationship does not exist, erroneous conclusions may be reached. Recent research has emphasized the potential shortcomings of the use of ratio variables. We demonstrate the importance of considering these shortcomings when lipid-normalizing data. Three examples are presented, and an alternative approach based upon the use of analysis of covariance (ANCOVA) is suggested.
Mercury and cadmium uptake from seawater and from food by the Norway lobster Nephrops norvegicus
Authors: Canli Mustafa , Furness Robert W. 
Published: March 2010

Abstract
Norway lobsters, Nephrops norvegicus, were fed on a mercury- and cadmium-rich diet for up to 50 d or were exposed to sublethal concentrations of organic mercury, inorganic mercury, or cadmium in seawater for 30 d. Cadmium taken up from seawater accumulated mainly in the hepatopancreas and gill, while it accumulated mainly in the hepatopancreas after feeding. Both organic and inorganic mercury taken up from seawater accumulated mainly in the gill, while highest concentrations were found in the hepatopancreas after the feeding experiment. Accumulation of organic mercury was higher than that of inorganic mercury. Although all treatments resulted in the accumulation of mercury and cadmium from seawater and food, tissue distribution of metals differed significantly among treatments. Distributions of organic and inorganic mercury also varied among tissues after uptake from seawater, with organic mercury being more evenly distributed among tissues than inorganic mercury, the latter being found predominantly in the gill.
Evaluation of liver histopathology and erod activity in St. Lawrence lake sturgeon (Acipenser fulvescens) in comparison with a reference population
Authors: Rousseaux Colin G. , Branchaud A. , Spear Philip A. 
Published: March 2010

Abstract
In an attempt to evaluate the effects of contaminants on the lake sturgeon Acipenser fulvescens, fish were netted from two sites: Rivière des Prairies, confluent with the St. Lawrence River near Montréal, and a reference site on the upper reaches of the Ottawa River in the La Verendrye Park. Livers of fish collected from the Rivière des Prairies were difficult to homogenize, and they left behind strands of what appeared to be connective tissue. Suspecting hepatic fibrosis, we decided to evaluate the livers for histopathologic changes. Nineteen adult lake sturgeon (eleven male and eight female) were examined. Following fixation, routine processing, sectioning, and staining with hematoxylin and eosin, microscopic evaluation revealed the following: Sections taken from livers of fish from the Rivière des Prairies site showed excessive fat accumulation and often severe chronic-active cholangiohepatitis. Bile duct proliferation (p &lt; 0.0001), periportal fibrosis (p &lt; 0.0001), inflammation (p &lt; 0.001), and fat accumulation (p &lt; 0.05) were more pronounced in the fish from the Rivière des Prairies site. Melano-macrophage centres appeared to be both paler and gave the appearance of fewer numbers (p &lt; 0.01). Livers from lake sturgeon taken from the reference site had a more normal appearance. The EROD levels were also significantly induced in these fish (reference 3.39 ± 0.57; Rivière des Prairies site 8.21 ± 0.87 pmol/mg protein/min; p &lt; 0.0005). The EROD levels positively correlated with bile duct proliferation (r2 = 0.44; p = 0.001) and periportal fibrosis (r2 = 0.41; p = 0.002). Despite the statistical associations above, we cannot categorically state that contaminants are the sole cause of the lesions seen.
Phototoxic response ofLumbriculus variegatusto sediments contaminated by polycyclic aromatic hydrocarbons
Authors: Monson Philip D. , Ankley Gerald T. , Kosian Patricia A. 
Published: March 2010

AbstractThe toxicity of certain polycyclic aromatic hydrocarbons (PAHs) to aquatic organisms can be greatly increased upon exposure of the organisms to ultraviolet (UV) radiation present in sunlight. The phenomenon of photoactivation of PAHs had received some attention in the laboratory; however, evaluation of the photoinduced toxicity of PAHs in field settings has been limited. In our studies, in situ chambers made from Pyrexr̀ glass tubes were used to evaluate the phototoxic response of laboratory-cultured oligochaetes (Lumbriculus variegatus) in sediments contaminated with PAHs. These experiments were conducted using both sunlight-exposed and shaded test chambers. In addition to the PAH-contaminated site, a reference site lacking PAHs was tested as a control. Survival of L. variegatus at the PAH-contaminated site was significantly less in chambers exposed to sunlight than in chambers held in the dark, or chambers from the reference site. Concurrent laboratory studies with sediment collected from the two sites and an artificial source of UV light corroborated observations made in the field. Although a number of PAHs were present at elevated concentrations in the test sample, further work is required to determine exactly which were responsible for the observed phototoxicity.