bluuebunny/crossref_metadata_2025_split huggingface dataset:
A modular estuarine mesocosm
Authors: Lauth John R. , Cherry Donald S. , Buikema Arthur L. , Scott Geoffrey I. 
Published: March 2010

Abstract
The need to simulate unique features of estuaries and the modes of entry of pollutants has led the authors to develop a modular approach to toxicity testing within an estuarine system. The approach incorporates replicate test systems that simulate the major aspects that are unique to estuarine systems. Initial validation of the design simulated a reference estuary on Wadmalaw Island, South Carolina. Replicate mesocosms were exposed to target concentrations 0, 2, and 8 μg/L of azinphosmethyl (AZM), an organophosphate insecticide. Single species toxicity tests were conducted within the systems in conjunction with the ecosystem simulations. High doses of AZM killed all animal life in the simulations, whereas lower concentrations showed a dose—response effect. Twenty-four-hour average AZM levels were used to calculate 24-h and 96-h LC50 values for Atlantic silverside minnows (Menidia menidia), mysid shrimp (Mysidopsis bahia), and grass shrimp (Palaemonetes pugio). Mysid shrimp were most sensitive to AZM (96 h LC50 = 0.811μg/L), whereas grass shrimp were least sensitive (96 h LC50 = 1.34 μg/L). Dissolved oxygen was reduced and ammonia concentrations increased from high doses of AZM. Increases in ammonia levels were not reduced by interstitial microbes, resulting in sustained high (&gt;0.08 mg/L) ammonia concentrations. Lower doses were quickly reduced in the mesocosm. This study demonstrates that ecosystem level responses can be evaluated by the modular approach. This modular approach can be modified to simulate most aquatic ecosystems.
Effects of colloids, flocculation, particle size, and organic matter on the adsorption of hexachlorobenzene to sediments
Authors: Tye Robert , Jepsen Rich , Lick Wilbert 
Published: March 2010

Abstract
Understanding and quantifying the dynamics of the sorption and partitioning of contaminants to sediments is essential in understanding and predicting the transport and fate of hydrophobic contaminants in aquatic environments. In previous work, the time-dependent effects of hexachlorobenzene (HCB) dissolution, the flocculation of colloidal matter from the water, and the flocculation of the suspended particles on the adsorption and partitioning of HCB to natural sediments from the Detroit River were investigated by means of batch-mixing experiments. These experiments were conducted for long times (up to 6 months) to be certain that a steady state had been reached. In the present study, this investigation has been extended, and the effects of colloids from the sediments and from the water, the flocculation of these colloids and of the sediments, particle size, and organic matter on HCB adsorption and partitioning have been quantified. It is shown that the measured steady-state partition coefficients depend on the amount of colloids from the water and from the sediments and on the amount of organic matter in the sediments. The adsorption rates depend on these quantities as well as the flocculation of the colloids, the flocculation of the sediments, and the particle size.
The daily changing pattern of hydrogen peroxide in new zealand surface waters
Authors: Herrmann Reimer 
Published: March 2010

Abstract
Concentrations of hydrogen peroxide (H2O2) were measured during daytime every 2 h at several depths in a catena of lakes of different trophic states including oligotrophic lakes Selfe and Oxbow, eutrophic Lake Hayes, dystrophic Lake Hochstetter, and a hypertrophic oxidation pond. The daily patterns of H2O2 of the various lakes can be explained firstly by the turnover regime of H2O2 which results out of simultaneous biological or chemical decay and formation yield (ratio of H2O2 formed per UV radiation dose) and secondly by internal transport. As in dystrophic, eutrophic, and hypertrophic lakes with high turnover, H2O2 is formed near the surface and the decay is rapid over the entire water column, a H2O2 pattern with sharp temporal and vertical gradients develops. In contrast, oligotrophic lakes allow deeper penetration of UV radiation, thus H2O2 is formed over greater depths. Further, the (biological) decay is slower than in lakes of higher trophic state leading to less sharp gradients within the daily H2O2 pattern. Input of H2O2 by wet deposition can contribute considerably to the increase of H2O2 in lakes, whereas dry deposition and groundwater flow do not.
Persistence of polycyclic aromatic compounds of different molecular size and water solubility in surficial sediment of an intertidal sandflat
Authors: Wilcock Robert J. , Corban Graham A. , Northcott Grant L. , Wilkins Alistair L. , Langdon Alan G. 
Published: March 2010

Abstract
The persistence of 13 polycyclic aromatic hydrocarbons (PAHs), ranging from two- to six-ring compounds, in an intertidal sandflat was studied by applying uniform amounts (0.10 g) of each to the surface of the sandflat and then monitoring concentrations over time. The mass of total PAH, after initial losses, declined slowly, so that after 256 d 12% of the applied material remained. Vertical concentration profiles indicated that little downward movement occurred and that most of the mass was concentrated in the top 2 cm, where most losses also occurred. The study has shown that anthropogenic PAHs have persistences comparable with organochlorine pesticides in aerobic sediments of intertidal sandflats. Rank correlations showed that the order of persistence may be predicted on the basis of molecular size parameters, such as molecular weight, molecular volume, and area. Persistence of PAHs in intertidal sandflats appears to be regulated by simple, physical processes.
Polycyclic hydrocarbon biomarkers confirm selective incorporation of petroleum in soil and kangaroo rat liver samples near an oil well blowout site in the western san joaquin valley, california
Authors: Kaplan Isaac , Lu Shan-Tan , Lee Ru-Po , Warrick Greg 
Published: March 2010

Abstract
Following an accidental oil well blow out at an oil field in the western part of the San Joaquin Valley, Kern County, California, soil samples and specimens of Heermann's kangaroo rats (Dipodomys heermanni) were collected from two oil-impacted areas and one control area. The chemical characteristics of the crude oil, soils, and rat livers were compared. Fingerprinting by gas chromatography—mass spectrometry and quantitative evaluation of metabolized petroleum hydrocarbons was performed on oil, soil extracts, and rat livers. A liver from a domestically raised rabbit was used as an experimental control. The results show that compared to background values for control samples and procedural blanks, there is no significant incorporation of PAHs or low molecular weight n-alkanes (C13–C25) into the liver tissues. The C25 to C35 n-alkane range for all soil samples, kangaroo rat livers, and rabbit liver, is dominated by a high abundance of C27, C29, C31, and C33 hydrocarbons typical of epicuticular plant waxes. In all liver tissue samples, squalene, the cholesterol precursor, is the dominant hydrocarbon. Although evidence is lacking for metabolism of PAHs and paraffinic petroleum hydrocarbons, very strong evidence is available for incorporation of a set of polycyclic hydrocarbons (biomarkers) belonging to the terpane, sterane, and monoaromatic and triaromatic sterane families, identified by ion monitoring at 191, 217, 253, and 231 m/z, respectively. Because these hydrocarbons are not known to exist in the biosphere, but are only synthesized during oil- and coal-forming processes, their presence in the liver samples constitutes proof for crude oil incorporation into tissues. This conclusion is further substantiated by the selective incorporation of only the 20S enantiomer of C28 and C29 steranes and aromatic steranes into the livers, with the exclusion of the 20R enantiomer. The results from the study conclusively demonstrate that polycyclic hydrocarbon biomarkers provide excellent indices for proof of petroleum exposure and metabolism in some terrestrial herbivores.
Selective assay for heavy metal toxicity using a fluorogenic substrate
Authors: Jung Keumhee , Bitton Gabriel , Koopman Ben 
Published: March 2010

Abstract
Chromogenic substrates have been generally used in enzymatic assays for the specific determination of heavy metal toxicity. A toxicity assay based on the specific inhibition of β-galactosidase by heavy metals and using a fluorogenic substrate was evaluated for its sensitivity to heavy metals and organic toxicants. The toxicity assay, FluoroMetPLATE, was specific for heavy metals and was more sensitive than the widely used Microtox assay. Except for lead, our assay displayed sensitivity similar to that of the 48-h acute Ceriodaphnia dubia assay. Monitoring of industrial samples showed that the FluoroMetPLATE assay gave similar results as the daphnid toxicity assay for 22 of 29 samples. For the remaining samples, for which there was no agreement between the two tests, it was found that the toxicity was mostly due to organic toxicants, confirming the specificity of FluoroMetPLATE for heavy metal toxicity.
Cytochrome p450 and contaminant concentrations in nestling black-crowned night-herons and their interrelation with sibling embryos
Authors: Rattner Barnett A. , Melancon Mark J. , Custer Thomas W. , Hothem Roger L. 
Published: March 2010

AbstractHepatic cytochrome P450-associated monooxygenase activities were measured in 11-d-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to Chincoteague National Wildlife Refuge, VA, USA) and three contaminated sites (Cat Island, Green Bay, WI, USA; Bair Island, San Francisco Bay, CA, USA; and West Marin Island, San Francisco Bay, CA, USA). Arylhydrocarbon hydroxylase and benzyloxyresorufin-O-dealkylase activities of nestlings from contaminated sites were only slightly elevated (less than threefold) compared with the reference site. Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. Pollutant concentrations of nestlings were rarely associated with monooxygenase activity. In contrast, concurrently collected pipping heron embryos (often siblings of the nestlings) exhibited pronounced monooxygenase induction (means at contaminated sites were elevated up to sevenfold and values of some embryos exceeded 25-fold induction). Furthermore, monooxygenase activity of pipping embryos was significantly correlated with total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents. The modest monooxygenase responses of heron nestlings suggest that this biomarker may have only limited value during this rapid-growth life stage.
Fate and transport of pcbs at the new bedford harbor superfund site
Authors: Garton Laurie S. , Bonner James S. , Ernest Andrew N. , Autenrieth Robin L. 
Published: March 2010

Abstract
A unique, holistic modeling approach, combining theoretical, empirical, and deterministic elements, was developed to define the ambient background transport of polychlorinated biphenyl (PCB) from New Bedford Harbor, to provide a baseline for remediation assessment of this Superfund site. Both empirical and deterministic elements characterized sediment processes. The deterministic section employed experimental data to describe flocculation through fluid shear, differential settling, and Brownian motion mechanisms, yielding a sediment settling velocity. The empirical portion of the model used this settling velocity, along with suspended solids, and flow field data to characterize sediment action. The remaining PCB transport mechanisms (volatilization and sorption) are theoretically considered to give a complete contaminant transport assessment. The PCBs in New Bedford Harbor tend to volatilize at the rate of 5.9 g/d; or sorb, with sorption coefficients increasing with percent chlorination from 10−22 to 10−04 m3/g for Aroclors 1016 and 1260, respectively, rather than stay in solution. The deterministic model showed that fluid shear was the most significant flocculation mass removal mechanism contributing to the settling velocity calculation. From the empirical model, the dominant sediment action mechanisms, resuspension and deposition, were driven by the change in suspended solids concentration and tides. The cycling of PCB-laden sediment, indicated by the PCB sorption tendency and the presence and dominance of resuspension, and subsequent transport from the site, can lead to PCB contamination of the water column, atmosphere, or downstream (marine) areas.
Dietary uptake efficiency of hcbp in channel catfish: The effect of fish contaminant body burden
Authors: Dabrowska Henryka , Fisher Susan W. , Dabrowski Konrad , Staubus Alfred E. 
Published: March 2010

Abstract
Goups of juvenile channel catfish (Ictalurus punctatus) were exposed for 10 days to control or contaminated sediment, spiked with 14C-hexachlorobiphenyl (HCBP, 130 μg·kg−1 dry weight), in order to establish a known body burden. At the completion of that exposure, subsamples offish were taken for HCBP analysis and the remaining fish were transferred to clean media. Each group transferred to clean media was then divided into two subgroups and offered either control or contaminated diet for 4 weeks. The contaminated diet (Tubifex worms) was spiked with 14C-HCBP (16.6 μg·kg−1 wet weight). Feeding rates of Tubifex were quantified as were fish growth rates and lipid levels. Fish (five specimens) were collected at the beginning of the dietary exposure and after 10, 20, and 30 days of exposure. Average individual growth rate constants were similar in all fish groups and ranged from 0.005 d−1 to 0.007 d−1. Both fish groups fed contaminated Tubifex accumulated HCBP in an apparent linear fashion over the study period. The bioaccumulation factors (BAFs) were 1.38 and 1.66 for accumulation from sediment and uptake from food, respectively. The dietary uptake efficiency for HCBP was found not to be affected by contaminant present in the fish body.
Toxicity, survivability, and activity patterns of northern bobwhite quail dosed with the insecticide terbufos
Authors: Brewer Rone A. , Carlock Linda L. , Hooper Michael J. , Brewer Larry W. , Cobb George P. , Kendall Ronald J. 
Published: March 2010

Abstract
The effects of the organophosphorus insecticide terbufos on laboratory-reared and wild northern bobwhites (Colinus virginianus) were investigated in laboratory dosing studies and dose-release field trials. Laboratory studies yielded a terbufos LD50 of 24.4 mg/kg-body weight (bw). All mortalities occurred within the first 24 h post-dose. Wild bobwhites were trapped, administered 0, 3, 5.6, or 21 mg/kg-bw terbufos by oral intubation, released at their trapping site, and monitored for 14 d. Mortality, activity, and locational data were recorded. Bobwhites treated with 21 mg/kg-bw terbufos had significantly lower survival (p = 0.04) than control birds, while survival at the lower doses was unaffected. No significant differences (p = 0.06) were detected in physical activity among treatments. The 21-mg/kg-bw dose yields an anticipated 37% mortality (or LD37) when interpolated from the LD50 slope equation. After adjustment for control mortality, the 21-mg/kg-bw dose led to 44% mortality in wild bobwhites. This was a 7% higher mortality than predicted by interpolation from the laboratory generated LD50. These results indicate that there was not a substantial increase in mortality of wild bobwhites compared to laboratory-reared bobwhites at nonlethal or lethal, sub-LD50, doses.
Environmental loads from water-sprinkled softwood timber. 1. Characteristics of an open and a recycling watering system
Authors: Borga Peter , Elowson Torbjörn , Liukko K. Ari 
Published: March 2010

Abstract
The concentrations of a number of organic and inorganic compounds in the wastewater from sprinkling of landstored softwood timber was monitored during a period of up to 18 weeks. A recycling system using a watering intensity of 160 mm/24 h, and an open system with intensities between 55 to 12 mm/24 h were studied. The compound classes investigated included dissolved organic carbon; distillable phenols; resin acids; bacterial phospholipid fatty acids (PLFA); organic and inorganic phosphorus, sulfur, and nitrogen; and a number of metal ions. In the recycling system, the peak concentrations occurred after 4 to 6 weeks, and the amounts accumulated through refilling of water largely exceeded those present in the wastewater at the end of the storage. In the open system, net loads of compounds occurred during the first weeks, which thereafter turned into uptakes for most compounds. The PLFA increased during the first weeks and clearly responded to the peak concentrations in the waters. Already from the start there were strong uptakes of nitrate, sulfate, and many minerals in the piles, suggesting that the supply of macro- and micronutrients necessary for microbial growth, as well as available terminal electron acceptors, may be a limiting factor for the extent of microbial degradation performed in the pile.
Aqueous uv radiation and uv/h2o2 oxidation of atrazine first degradation products: Deethylatrazine and deisopropylatrazine
Authors: Beltrán Fernando J. , González Manuel , Rivas Francisco J. , Alvarez Pedro 
Published: March 2010

Abstract
The UV photolysis and H2O2/UV advanced oxidation of two intermediate compounds of the degradation of atrazine in water, deethylatrazine and deisopropylatrazine, have been studied. The influence of hydrogen peroxide and bicarbonate ion concentrations was observed both in organic-free water and in surface waters. Both UV photolysis and UV/H2O2 oxidation techniques lead to significant rates of elimination of these compounds, although they were lower in surface waters, likely due to the presence of natural radical scavengers. However, in the presence of 0.01 M bicarbonate ion, degradation rates were similar regardless of the type of water used. A kinetic study of both techniques was also conducted. Quantum yields and rate constants of the reaction between the hydroxyl radical and both intermediates were determined.
A comparison of two methods of estimating bird mortalities from field-applied pesticides
Authors: Madrigal J.L. , Pixton Glen C. , Collings Bruce J. , Booth Gary M. , Smith H. Duane 
Published: March 2010

Abstract
At least two search methods for bird carcasses have been suggested to estimate bird mortality from the use of a pesticide, one outlined by the U.S. Environmental Protection Agency (EPA) and one we propose. The proposed estimator provides a nonparametric, model-free procedure for estimation of nontarget bird kills. Data were collected during a field study to compare the methods. These data were used to provide parameters for a computer simulation comparing characteristics of the mortality estimates produced by the two methods. The proposed method demonstrates marked advantages with respect to bias and mean squared error when compared to several interpretations of the EPA method in various search and mortality scenarios. In addition, the proposed method often provides estimates in instances where the EPA method cannot. The proposed estimator allows the estimation of search efficiency and survival probability simultaneously.
Copper in indigenous and transplanted zebra mussels in relation to changing water concentrations and body weight
Authors: Mersch Jacques , Wagner Philippe , Pihan Jean-Claude 
Published: March 2010

Abstract
Zebra mussels, Dreissena polymorpha, were collected monthly from a copper-contaminated reservoir over a period of nearly 3 years. Copper concentrations in the organisms showed marked fluctuations reflecting changes in the water contamination. Bioconcentration patterns were influenced by the specific capacity of this sentinel organism to biologically integrate the continuously evolving water pollution; the sampling pattern, which inevitably introduced a certain subjectivity into monitoring results; and weight changes in the animals within the yearly cycle. Consequently, the successive monthly indications obtained with the zebra mussels provided a current biological assessment of a complex dynamic contamination situation. In a second experiment, caged mussels from three different populations were transferred for 3 months into the reservoir and sampled on six occasions. Mortality rates, attachment capacity, and a condition index revealed no substantial fitness disturbances in the transplanted organisms. Differences in dry weight throughout the experiment were attributable to the initial characteristics of each population. The influence of body mass on monitoring results was eliminated by replacing copper concentrations (μg/g dry weight) with copper burdens (μg/specimen). In terms of copper burdens, the three transplanted populations exhibited very similar metal patterns. Moderate quantitative differences between introduced and indigenous populations were interpreted as the result of physiological adaptation of the indigenous mussels to their contaminated environment. This study showed that the transfer technique with D. polymorpha is a useful tool for active biomonitoring programs.
Use of an mfo-directed toxicity identification evaluation to isolate and characterize bioactive impurities from a lampricide formulation
Authors: Hewitt L. Mark , Munkittrick Kelly R. , Scott Ian M. , Solomon Keith R. , Servos Mark R. , Carey John H. 
Published: March 2010

Abstract
Recently, a field formulation of the lampricide containing 3-trifluoromethyl-4-nitrophenol (TFM) was identified as a potent inducer of mixed-function oxygenase (MFO) detoxification enzymes in fish. It was further shown that induction was not associated with primary formulation ingredients. Using a toxicity identification evaluation (TIE) approach based on rainbow trout hepatic MFO activity, the TFM field formulation was investigated to isolate the compound(s) responsible for induction. Solid phase extraction and reverse-phase high-pressure liquid chromatography (HPLC) isolated activity in two distinct fractions, which were profiled by gas chromatography–high-resolution mass spectrometry. The major constituents in both fractions were confirmed by synthesis as nitro-, trifluoromethyl-, and/or chloro-substituted diphenyl ethers. However, fish exposures to the pure compounds failed to cause MFO induction. After further fractionations by HPLC, induction was determined in three new subfractions. Confident identification of a chloro-nitro-trifluoromethyl-substituted dibenzo-p-dioxin has been made in two of these fractions. Although the specific chemicals responsible for induction have not been confirmed, a suite of impurities including chloro-, and/or nitro-, and/or trifluoromethyl-substituted phenols, diphenyl ethers, and dibenzo-p-dioxins have been identified in the formulation. It is likely that these materials originate during industrial synthesis of TFM. These findings suggest that additional structurally related impurities are also present in this formulation.