bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of water pH on copper toxicity to early life stages of the common carp (Cyprinus carpio)
Authors: Stouthart Xander J. H. X. , Haans Jeroen L. M. , Lock Robert A. C. , Bonga Sjoerd E. Wendelaar
Published: March 2010

Carp eggs were exposed immediately after fertilization to Cu concentrations of 0.3 and 0.8 μmol/L at water pH 7.6 or pH 6.3. Mortality, the incidence of spinal cord deformation, heart rate, tail movements, hatching success, and whole-body content of K, Na, Mg, Ca, and Cu were determined over time. Light microscopical preparations of eggs (48 h after fertilization) and larvae (168 h after fertilization) were studied. At pH 7.6, Cu did not affect egg mortality, heart rate, tail movements, and whole-body K and Mg content. Hatching success increased only in the 0.3 μmol/L Cu group. Exposure to 0.8 μmol/L Cu increased larval mortality and larval deformation and decreased whole-body Na and Ca content. At pH 6.3, exposure to 0.8 μmol/L Cu increased egg mortality and decreased heart rate and tail movements. Furthermore, premature hatching, a concentration-dependent increase of larval mortality, and larval deformation was observed. Exposure to 0.3 and 0.8 μmol/L Cu decreased the whole-body content of K, Na, Mg, and Ca. Uptake of Cu after hatching increased two-fold at pH 6.3 compared to the pH 7.6 groups. At pH 6.3, all Cu-exposed larvae were unable to fill their swim bladder. Also, after 168 h the yolk sac remained largely unabsorbed in the 0.3 and 0.8 μmol/L Cu group. Exposure to 0.8 μmol/L Cu resulted in coagulation of proteins in eggs and yolk sacs. No significant changes in any of the assessed parameters were observed in control groups of pH 6.3 and pH 7.6.
Modeling dose response using generalized linear models
Authors: Kerr David R. , Meador James P.
Published: March 2010

This paper describes a method to determine and model dose–response relationships from binomial response data using generalized linear models (GLM). The main advantage of this technique is that it allows LCp or LDp to be determined without an initial linearizing transformation. (LCp and LDp are the lethal concentration or dose that causes p proportion of test animals to die at a specified time period.) Thus, the method of GLM is an appropriate way to analyze a dose–response relationship because it utilizes the inherent S-shaped feature of the toxicologic response and incorporates the sample size of each trial in parameter estimation. This method is also much better behaved when the extremes of the response probability are considered because responses of 0% and 100% are included in the model. Another advantageous feature of this method is that confidence intervals (C.I.s) for both the dose estimate and response probabilities can be computed with GLM, which provides a more complete description of the estimates and their inherent uncertainty. Because C.I.s for both the dose estimate and response probabilities can be constructed, the lowest observed effect concentration (LOEC) can also be determined.
Toxicokinetics-based survival analysis in bioassays using nonpersistent chemicals
Authors: Widianarko Budi , VanStraalen Nico
Published: March 2010

Present statistical analysis of survivorship data obtained from bioassays using nonpersistent toxicants does not explicitly take into account that exposure decreases with time due to degradation of the toxicant. Such a situation typically occurs in static aquatic toxicity tests and in soil tests. We develop a model for the analysis of survival data obtained in such experiments and show how estimates for the initial LC50, the degradation rate constant, and the elimination rate constant may be obtained from observations on time-dependent survival rates. The model assumes linear one-compartment toxicokinetics with exponentially decreasing input. The probability of dying is assumed to be directly proportional to the internal concentration. An explicit expression for time- and concentration-dependent survival is obtained. The model predicts that, with increasing exposure time, survival will approach a nonzero baseline value for certain initial concentrations. Application of the model is illustrated by curve-fitting to experimental observations, made over 6 weeks, for the effect of diazinon on the terrestrial isopod Porcellio scaber. The fit to data is fairly good, but the parameter estimates tend to have a high coefficient of variation. A considerable increase of precision may be obtained if the degradation rate constant is given a fixed value (for example, following from chemical residue analysis of the medium). The approach is applicable to all situations where, due to loss of the toxicant during the test, mortality shows no further increase after a certain exposure period.
Evaluating risk predictions at population and community levels in pesticide registration-hypotheses to be tested
Authors: Kapustka Lawrence A. , Williams Bill A. , Fairbrother Anne
Published: March 2010

Chemical registrations under FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) and TSCA (Toxic Substance Control Act) in the United States, and equivalent regulations in Canada and Europe, are driven extensively by risk assessments. Chemicals intended for use as pesticides are evaluated by considering fate and transport, toxicity, and assumed exposure scenarios. For nonpesticide chemicals, very limited testing information is generated to support the risk management decisions. Despite the restricted quantity of information, risk-based predictions are intended to provide analyses that are adequate to evaluate ecological safety margins. Persistent questions regarding adequacy of protection have dogged risk assessors, regulators, and registrants. From a scientific perspective, risk assessments are essentially complex hypotheses, not conclusive or factual statements. Given the great reliance on extrapolations from individual-based toxicity (and generally poor exposure characterizations) to statements of community, ecosystem, landscape, regional, and even global levels of organization, it is perhaps remarkable that the system has worked at all. But do we really know if the system works? If we wish to retain a scientific basis in registration, follow-up work that tests the risk-prediction hypotheses needs to be done. Properly structured around testable parameters, focused monitoring programs could reduce much of the mystery embodied in current practice. Greater reliance on monitoring data to test risk predictions could reduce the tendency to concatenate uncertainty factors that unnecessarily expand Type II errors. We propose changes in the registration process to address these concerns.
Interactions of Cd and Cu in anaerobic estuarine sediments. I. Partitioning in geochemical fractions of sediments
Authors: Rule Joseph H. , Alden Raymond W.
Published: March 2010

Partitioning of Cd and Cu between geochemical fractions of an a aerobic estuarine sediment was determined after equilibrating fine-sandy sediment with different combinations of added Cd (0, 2.5, 5 mg/kg) and Cu (0, 12.5, 25 mg/kg). Sediments were placed in aquaria with 20 ppt seawater where bioassay test organisms were exposed for 14 d. At the start and conclusion of the experimental period, sediments were sequentially extracted to determine the elemental content of the exchangeable (EP), easily reducible (ERP), organic-sulfide (OSP), moderately reducible (MRP), and acid extractable (AEP) phases. Partitioning of the metals in both the native and treated sediments was, for Cd: OSP ≫ ERP > AEP > EP (MRP was below detection) and for Cu: OSP ≫ AEP > ERP > MRP > EP. Cadmium extracted in all phases and Cu in the EP, ERP, and OSP were proportional to the respective treatments. The EP-Cd, ERP-Cd, and OSP-Cd were affected by the Cu treatment and significant interactions occurred between Cd and Cu for the EP-Cd, ERP-Cd, OSP-Cd, EP-Cu, and ERP-Cu. Increasing levels of applied Cd and Cu resulted in greater amounts of EP-Cd and ERP-Cd, fractions that are the most bioavailable and the most readily available for desorption into the water column. A significant conclusion is that the input of nontoxic metals may affect the geochemical phase distribution, potential bioavailability, and toxicity of native sediment metals.
Biodegradation of triethanolamine
Authors: West Robert J. , Gonsior Stanley J.
Published: March 2010

Triethanolamine production in the United States exceeds 100,000 metric tons per year. Given this magnitude of production and widespread distribution to consumer product, specialty chemical, and agricultural chemical markets, an understanding of the environmental fate and lifetime of this chemical is warranted. Studies were conducted to determine the fate and lifetime of [14C]triethanolamine in an aerobic surface soil, freshwater river systems, and in activated sludge waste treatment. The half-life determined for biodegradation of triethanolamine ranged from 0.02 to 0.10 d in reactions containing 818 mg/L mixed liquor activated sludge solids from a municipal wastewater treatment facility. The half-life of triethanolamine in a sandy loam surface soil ranged from 0.5 to 1.8 d for initial concentrations ranging from 0.01 to 13.4 mmol/kg (1.4–2,000 mg/kg dry wt). Biodegradation was also measured in two different river waters, with an average half-life (±1 SD) of 1.2 ± 0.5 d determined for initial triethanolamine concentrations of 0.67 and 3.28 μmol/L (99 and 489 μg/L). The kinetics of both primary biodegradation and mineralization were shown to be generally first-order in triethanolamine and biomass concentrations (second-order overall) for the matrices and range of triethanolamine concentrations tested. When these relatively short half-lives are related to typical chemical residence times in various environmental compartments, it can be concluded that biodegradation would prevent accumulation of triethanolamine and its associated degradation products in the environment.
Persistence of herbicide residues in Gammarus lacustris (crustacea: Amphipoda) in Prairie wetlands
Authors: Arts Michael T. , Headley John V. , Peru Kerry M.
Published: March 2010

Tandem mass spectrometry (MS) was used to detect herbicide residues in wild populations of amphipods collected from microcosms spiked with a single pulse of either Avadex®-BW (triallate) or HoeGrass® (diclofop-methyl) at three different concentrations (1.0, 10.0, and 100.0 μg·L−1). Independent confirmations of both herbicides were obtained by spiking amphipod tissues with 50 pg of authentic standards of triallate or diclofop-acid. The in situ microcosm experiments demonstrated that positive confirmation of triallate could still be made 30 d following an initial single spike of 10 μg·L1 triallate. Diclofop-acid could still be detected in lipid-rich tissues of amphipods 10 and 15 d following an initial spike concentration of 10 and 100 μg·L1, respectively. The chief advantages of tandem MS include the ability to analyze small quantities of tissue (<1 mg wet weight), the ability to detect picogram levels of target analytes, and user flexibility in the choice of tissue to be analyzed (e.g., lipid-rich storage tissue, muscle, nervous tissue, etc.).
Uptake of chlorobenzenes by tissues of the soybean plant: Equilibria and kinetics
Authors: Tam Deborah D. , Shiu Wan-Ying , Qiang Kang , Mackay Donald
Published: March 2010

Measurements are reported of the uptake equilibria and kinetics of seven chlorobenzenes: 1,2–dichlorobenzene, 1,3–di-chlorobenzene, 1,2,4–trichlorobenzene, 1,2,3,4–tetrachlorobenzene, 1,2,3,5–tetrachlorobenzene, pentachlorobenzene, and hexachloro-benzene from water into tissues (leaves, petioles, stems, and roots) of 6–8–week-old soybean plants, Glycine max L. Equilibrium was reached within 1–4 days, with uptake of the more hydrophobic chemicals being slightly slower. Aqueous solubilities of three of these chlorobenzenes are reported. Linear correlations were obtained between the equilibrium tissue-water partition coefficients, the chemicals' octanol-water partition coefficients and the measured lipid contents. A correlation approach is proposed that may be useful for assessment of the extent of uptake of persistent hydrophobic chemicals by plants from soil and the atmosphere.
Monitoring the effects of five “nonherbicidal” pesticide chemicals on terrestrial plants using chlorophyll fluorescence
Authors: Rugh Brent W. K. , Miles Donald
Published: March 2010

This experiment was carried out in anefforttodetermine if several commonly encountered “nonherbicidal” pesticides can affect the photosynthetic electron transport capacity of plants, and if so, can the effects caused by these pesticides be detected by chlorophyll fluorescence induction analysis. The study involved the incubation of excised leaves of mung beans (Phaseolus vulgaris L.) in five pesticidal chemicals: carbofuran, tributyltin chloride, chlorpyrifos, phorate, and fonofos. Diuron, a well-known inhibitor of photosynthesis was used as a positive control. Following chlorophyll fluorescence induction analysis of the mung bean leaf cuttings, the Fv /Fm and Fq parameters (a measure of the quantum efficiency and the fluorescence quenching capacity, respectively) were analyzed. Diuron dramatically decreased the Fv /Fm and the F values of the mung bean leaf cuttings following 2 h exposure to concentrations as low as 2.0 μM. Phorate also caused a significant decrease in the Fv /Fm values of mung bean leaf cuttings; however, the decrease was considerably less than that caused by diuron and did not appear until the treatment concentration reached 200 μM. There was no apparent change in the Fv /Fm values of the mung bean leaf cuttings treated with the other pesticidal chemicals. Both phorate and tributyltin chloride caused decreases in the Fq values of mung bean leaf cuttings though not as dramatic as the decreases from diuron treatment. The decreases in the fluorescence quenching capacity of mung bean leaf cuttings occurred with exposure to 20 μM tributyltin chloride but not until exposure to 200 μM of phorate. These results indicate that some nonherbicidal pesticides can adversely affect certain species of plants and that chlorophyll fluorescence induction analysis can be used to detect these effects.
Degradation of 3,5-dimethyl-tetrahydro-2H-1,3,5-thiadiazine-2-thione in aqueous aerobic media
Authors: Subramanian Periyasamy , Teesch Lynn , Thorne Peter S.
Published: March 2010

Decomposition of 3,5-dimethyl-tetrahydro-2H-1,3,5-thiadiazine-2-thione (DTTT) has been studied by UV-visible spectroscopy (UV-VIS), high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and fast atom bombardment-mass spectrometry (FAB-MS). Hydrolysis rate constants for DTTT and rate constants for product formation were measured. The partially hydrolyzed and aged DTTT solutions have been separated and analyzed by GC-MS. Formaldehyde, 1,3-dimethyl-2-thiourea, N -methyl dithiocarbamic methyl ester, N -methyldithiocarbamic perthiomethyl ester, 2-methyl-5-dihydro-3H-4-thia-1,2-isooxazolidine-3-thione, 1,3,5-trimethyl-hexahydro-2H-1,3,5-triazine-2-thione, 4-methyl-5-methylimino-1,2,4-dithiazolidine-3-thi-one, and 2,4-dimethyl-1,2,4-thiadiazolidine-3,5-dithione were identified from the hydrolyzed DTTT solution. Methyl isothiocyanate, which is one of the intermediates formed during the decomposition of DTTT, was also monitored by UV-VIS and HPLC for the formation of common products and characterized by GC-MS. The decomposition pathways for DTTT are presented and are in accord with the limited literature data. Environmental impact assessment of the DTTT and its metabolites is summarized.
Effects of grasshopper-control insecticides on survival and brain acetylcholinesterase of pheasant (Phasianus colchicus) chicks
Authors: Martin Pamela A. , Ohnson Daniel L. J. , Forsyth Douglas J.
Published: March 2010

Ring-necked pheasant (Phasianus colchicus) chicks were exposed via contact and/or ingestion to formulations of three insecticides (Lorsban 4E, chlorpyrifos; Cygon 480E, dimethoate; and Furadan 480F, carbofuran) applied to pasture plots at one and four times the rate recommended for control of grasshoppers (Orthoptera: Acrididae) in prairie Canada. Chicks (3 d old) were exposed for 48 h in pens with the sprayed vegetation and were fed either unsprayed grasshoppers or grasshoppers sprayed at the same rates as the vegetation. Control groups were exposed to unsprayed vegetation and received unsprayed grasshoppers. Three replicates were conducted throughout June and early July 1992.

Although some signs of acetylcholinesterase (AChE) depression were observed in chicks exposed to insecticides, there was no difference in the number of mortalities among treatment and control groups. Chicks that died during the exposure period gained significantly less weight than survivors in all groups. Among surviving chicks, weight gains of those exposed to the high- rate Furadan treatment consuming sprayed food were significantly lower than those of controls (1.8 vs. 6.6 g/d). Brain AChE activity was lower overall in surviving chicks than in those that died; it was not significantly reduced among chicks that died in any treatment group. Overall, survivors of Furadan- exposed treatment regimes had lower AChE activity than those of Cygon and Lorsban treatments; birds in high-spray-rate treatments of all insecticides had lower AChE activity than those in all low-spray-rate treatments; and birds in all treatments consuming sprayed grasshoppers had lower AChE activity than those fed unsprayed grasshoppers. Food consumption was not affected by any treatment.
Synergy between deltamethrin and prochloraz in bees: Modeling approach
Authors: Chalvet-Monfray Karine , Sabatier Philippe , Belzunces Luc P. , Colin Marc E. , Fléché Cécile
Published: March 2010

The metabolic hypothesis proposes that the fungicide prochlorazacts synergistically on deltamethrin by inhibiting oxidative metabolism of deltamethrin. The limits of validity of this hypothesis were tested using a pharmacokinetic box model. Experimental work showed that bee mortalities were higher after 2 h in groups sprayed with deltamethrin at 0.25 g-ha−1 in the presence of prochloraz (25 g-ha−1) than in those sprayed at 1 g-ha−1 with deltamethrin alone. We defined t as the time at which the internal concentration of deltamethrin is the same for both treatments. For the metabolic hypothesis to be consistent with experimental results, t must be less than 2 h. Given t < 2 h, the model was used to study pharmacokinetic parameter values. Published parameter values were inconsistent with simulation results because in all cases t was greater than 2 h. Consequently, the synergy between prochloraz and deltamethrin cannot be explained by the inhibition of oxidative metabolism.
Neogastropod imposex for monitoring recovery from marine tbt contamination
Authors: Tester Monica , Ellis Derek V. , Thompson J. A. Jeffrey
Published: March 2010

Imposex, the imposition of male sexual characters on female snails, was used as a bioindicator of recovery from tributyltin (TBT) pollution in the Pacific Northwest. Whelks surveyed before TBT use was regulated had shown a high frequency of affected females in the Strait of Juan de Fuca and the Strait of Georgia; and lower frequency on the west coast of Vancouver Island. A reduction in imposex is now evident on the west coast of Vancouver Island and in some locations in the Strait of Georgia. There is no clear evidence of recovery near Victoria, and Vancouver Harbour still does not have whelks in any abundance, if at all. Of the four species studied, Nucella emarginata is the most suitable bioindicator species because it is abundantly distributed and has the shortest lifespan (1–2 years). When frequency of imposex remains at 100%, the FPL (female penis length) is still available as a useful bioindicator.
Effects of diazinon on large outdoor pond microcosms
Authors: Giddings Jeffrey M. , Biever Ronald C. , Annunziato Maria F. , Hosmer Alan J.
Published: March 2010

An aquatic microcosm study (simulated aquatic field study) was conducted with the technical grade of the organophosphorus insecticide diazinon. Eighteen fiberglass tanks, each 3.2 m in diameter and 1.5 m in depth, were established with sediment and water (11.2 m3) from natural ponds and stocked with 40 juvenile bluegill sunfish (Lepomis macrochirus). Diazinon was applied in aqueous solution three times at 7-d intervals. Eight loading rates were used, with two microcosms at each level plus two controls. The amounts of diazinon added during each application corresponded to theoretical concentrations from 2.0 μg/L to 500 μg/L. The most sensitive ecological components of the microcosms were Cladocera (zooplankton), and Pentaneurini and Ceratopogonidae (insects), which were reduced at all treatment levels. Effects on many zooplankton and macroinvertebrate taxa occurred at diazinon concentrations (time-weighted averages) of 9.2 μg/L and higher. Total fish biomass was reduced at 22 μg/L and higher, and fish survival was reduced at 54 μg/L and higher. Odonates, some dipterans, and plants were not adversely affected by diazinon at 443 μg/L, the highest concentration tested. Microcosm results were consistent with laboratory toxicity data for some taxa (e.g., cladocerans, Ephemeroptera, and bluegill sunfish), but differed substantially for others (e.g., rotifers, Chironomini, and odonates). The no-observed-effect concentration (NOEC) in the microcosms (70-d time-weighted average) was near the 10th percentile of single-species LC50 values.
A modular estuarine mesocosm
Authors: Lauth John R. , Cherry Donald S. , Buikema Arthur L. , Scott Geoffrey I.
Published: March 2010

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 (>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

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

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

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

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

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

Hepatic 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

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

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

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

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

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

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

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

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.
Histochemical detection of lead in plant tissues
Authors: Tung Gabrielle , Temple Patrick J.
Published: March 2010

A histochemical staining technique using sodium rhodizonate was developed for detecting lead in living or preserved plant tissues. Sodium rhodizonate formed a bright scarlet-red precipitate with lead at pH 3.0, but showed no significant color responses with other metals. The precipitation of lead by this staining technique was confirmed by detection of lead in the red-stained precipitate with electron microscopy X-ray analysis. This histochemical technique for lead provided rapid, quantifiable, and unambiguous evidence for the accumulation and localization of lead in plant tissues. Soil-borne lead accumulated primarily in the roots, although at high concentrations, lead also accumulated at the ends of transpirational streams, particularly at hydathodes, trichomes, and the termini of xylem streams. Lead deposited from the atmosphere accumulated on the surface of conifer foliage and also appeared in or on cell walls of various internal cells and tissues. Lead concentrations in foliage and the color intensity of the stained deposits in spruce foliage decreased with distance from the lead source and increased with age of needles. No evidence of lead deposition inside cell contents was observed by this stain.
Effects of metal contamination from mine tailings on allozyme distributions of populations of great plains fishes
Authors: Roark Shaun , Brown Karen
Published: March 2010

This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining District in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. Although total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness, and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (Gpi) in F. notatus and P. notatus, malate dehydrogenase (Mdh) in G. affinis, and phosphogluconate dehydrogenase (Pgdh) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for Gpi and Pgdh loci, but not for products of the Mdh locus. No sensitivity to lead was noted for allozymes. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results provide additional support for the use of genetic structure and variability as a bioindicator of heavy metal contamination.