bluuebunny/crossref_metadata_2025 huggingface dataset:
Using biodegradation kinetics to measure availability of aged phenanthrene to bacteria inoculated into soil
Authors: Schwartz Egbert , Scow Kate M
Published: March 2010

The rate of biodegradation of pollutants in soil can be limited by the pollutant's availability to microorganisms. We have developed a bioassay for the availability of phenanthrene to bacteria that degrade phenanthrene in soil. The assay uses a soil in which phenanthrene is degraded very slowly. The rate of phenanthrene mineralization in this soil may be increased substantially through bioaugmentation with a bacterial inoculum. By delaying inoculation, it is possible to manipulate the time phenanthrene is present in soil before accelerated biodegradation begins. A phenanthrene concentration much lower than the affinity constant of the inoculum is added; thus, biodegradation kinetics approach first order. Because the phenanthrene first-order rate constant for the inoculum is the same regardless of the phenanthrene residence time in soil, the change in phenanthrene availability to the inoculum can be measured over time. The availability of phenanthrene to bacteria declined in a biphasic double exponential pattern with time. The initial rapid decline in availability resembled the change in amount of phenanthrene extracted from soil with hexane-water. However, after phenanthrene had been present in the soil longer than 300 h, the fraction extracted with hexane-water declined faster than the substrate available to the bacterial inoculum, suggesting that the bacteria are able to access a pool of phenanthrene unavailable to hexane.
Sorption and bioavailability of carbon tetrachloride in a low organic content sandy soil
Authors: Zhao Xianda , Szafranski Michael J , Maraqa Munjed A , Voice Thomas C
Published: March 2010

Two sets of parallel columns were packed with a low-organic-content aquifer soil contaminated with carbon tetrachloride (CT) and flushed with water under bioactive and abiotic saturated conditions. Both effluent and soil concentrations (by sacrificing columns) were monitored for CT. Desorption of CT from the aquifer material could be described by a two-site nonequilibrium model. The columns were found to operate far from desorption equilibrium conditions. Inoculation with Pseudomonas sp. strain KC resulted in rapid transformation of CT in the liquid phase, but no evidence of solid-phase degradation was found. Mathematical modeling of desorption and biodegradation as sequential and independent processes appears to be justified for this soil/contaminant combination.
Reduction of 1,2-dibromoethane in the presence of zero-valent iron
Authors: Rajagopal Venkat K , Burris David R
Published: March 2010

The degradation reaction of 1,2-dibromoethane (ethylene dibromide or EDB) in water was studied in the presence of zero-valent iron (acid-cleaned, cast iron) in well-mixed batch aqueous systems. The observed products were ethylene and bromide ions. Carbon and bromine mass recoveries of ≥ 95% were obtained. Bromoethane and vinyl bromide were not observed. The reduction rates of bromoethane and vinyl bromide with iron indicate that they should have been observed if they were significant reaction intermediates for EDB. The results indicate that reductive β-elimination may be the dominant reaction pathway. Reaction kinetics are rapid and pseudo-first order. The activation energy was determined to be 50 kJ/mol, indicating that the reaction rate may not be aqueous phase diffusion controlled but rather controlled by the chemical reaction rate on the iron surface. Metallic iron may be a suitable treatment approach for EDB-contaminated groundwater in above-ground, as well as in situ applications, due to rapid kinetics and nontoxic products.
Chronic toxicity of 2,4,6-trinitrotoluene to a marine polychaete and an estuarine amphipod
Authors: Green Andrew , Moore David , Farrar And Daniel
Published: March 2010

The chronic toxicity of sediment-associated 2,4,6-trinitrotoluene (TNT) to the marine polychaete Neanthes arenaceodentata and the estuarine amphipod Leptocheirus plumulosus was evaluated. Test organisms were exposed to sediments spiked with radiolabeled TNT for 28 d, after which time the endpoints of mortality, growth, and reproduction (L. plumulosus only) were assayed and compared against the TNT tissue concentrations as well as the TNT sediment concentrations. Survival was significantly reduced at a tissue concentration of 61 μg TNT/g wet wt tissue in N. arenaceodentata and at 6.3 μg TNT/g wet wt tissue in L. plumulosus. The growth end point demonstrated an apparent hormesis effect in both N. arenaceodentata and L. plumulosus with enhancement (significant for N. arenaceodentata) occurring at the lower TNT concentrations. Growth was significantly reduced at the highest TNT exposure of 10.0 μg TNT/g wet wt tissue in L. plumulosus. Reproduction was significantly reduced at a tissue concentration of 6.3 μg TNT/g wet wt tissue in L. plumulosus. The results of this study demonstrate that both N. arenaceodentata and L. plumulosus are sensitive to the presence of sediment-associated TNT and that more information is needed about the toxicity of TNT to benthic fauna to facilitate risk assessment and management of TNT-contaminated sites.
Direct effect of ammonia on three species of north american anuran amphibians
Authors: Jofre Mariana B , Karasov William H
Published: March 2010

Leopard frog (Rana pipiens), green frog (Rana clamitans), and American toad (Bufo americanus) embryos were exposed to different un-ionized ammonia (NH3) levels over an ecologically relevant range (0–2 mg NH3/L H2O). Hatching success and prevalence of deformities were recorded after acute exposures (3–5 d duration) at 23°C and pH 8.7. Green frog tadpoles were exposed to different NH3 levels in a subchronic experiment (114 d), and growth, survival, and metamorphosis were monitored. Survival declined, the prevalence of deformities increased, and growth and development were slow in anuran embryos and tadpoles exposed to NH3 concentrations in excess of 0.6 mg/L (green frogs) or 1.5 mg/L (leopard frogs). No effects were observed in American toads up to a concentration of 0.9 mg/L NH3. It appears from the few data available that anurans may not be particularly sensitive to NH3 when compared with many fish species and that water quality criteria determined using data collected on fish species will be protective for many anuran amphibians. The NH3 concentrations that caused negative effects in these experiments are higher than measured values for water in the Fox River–Green Bay ecosystem (WI, USA) but lower than for pore sediment water. In this ecosystem, anuran amphibians are potentially exposed to hazardous levels of NH3 when they hibernate on the bottom or buried in sediments or during episodic releases of NH3 from sediments.
Whole-fish versus filet polychlorinated-biphenyl concentrations: An analysis using classification and regression tree models
Authors: Amrhein James F , Stow Craig A , Wible Clay
Published: March 2010

Fish polychlorinated-biphenyl (PCB) measurements usually represent one of two different sample types: filets or homogenized whole fish. Filet measurements are more appropriate for use if the goal of analysis is estimating human PCB consumption, while whole-fish analysis may be more useful for quantifying and understanding processes of contaminant flow and bioaccumulation. While it is generally assumed that whole-fish PCB concentrations exceed filet concentrations because of the presence of fatty internal organs in whole-fish samples, the literature contains no reported comparisons of filet versus whole-fish PCB concentrations. We measured total PCB concentrations in filets and whole-fish samples from the same individuals in Lake Michigan coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss). The average whole-fish to filet PCB concentration ratio was 1.70 for coho salmon and 1.47 for rainbow trout, but it varied considerably among individuals, with a few fish exhibiting a higher concentration in the filet than in the whole-fish sample. Classification and regression tree (CART) models indicated that filet PCB concentration and fish length were the best predictors of whole-fish PCB concentration, whereas filet and whole-fish lipid concentrations where less important predictors. Lipid normalization of the PCB data decreased within-individual variability, was equivocal with respect to variability among individuals, and accentuated the between-species difference. Both species exhibit a pronounced 1:1 relationship between the whole-fish to filet PCB concentration ratio and the whole-fish to filet lipid concentration ratio; however, we point out that there is a strong spurious component to this relationship, which indicates that the relationship may be more algebraic rather than an indication of underlying mechanisms.
Gray-tailed voles do not move to avoid exposure to the insecticide Guthion® 2S
Authors: Wang Guiming , Wolff Jerry O , Edge W Daniel
Published: March 2010

We used the gray-tailed vole, Microtus canicaudus, as an experimental model species to test an assumption of the quotient method that nontarget wildlife do not move out of a contaminated area to avoid exposure to potentially harmful agricultural chemicals. In May 1997, we placed voles into 12 0.2-ha enclosures planted with a mixture of pasture grasses. In late July, we applied 1.5 kg/ha of the insecticide Guthiont 2S (azinphos-methyl), in three treatments; full spray (all of the habitat sprayed with Guthion 2S), half spray (one half of the habitat sprayed with Guthion 2S and one half sprayed with water), and a control (all of the habitat sprayed with water). Five replicates were used for the half spray and control, and two replicates were used for the full spray. We radio-tracked 44 female and three male voles before and after the spray treatment. None of the 47 animals moved out of their established home ranges after treatment and no animals moved from the contaminated to uncontaminated areas. Additionally, no biologically meaningful differences occurred in home range size, mean maximum distance moved, or average distance between two successive radio locations. Reproducing adult voles were relatively sedentary and did not leave their established home ranges in response to insecticide exposure. These results suggest that small mammals are not likely to reduce exposure by moving from the contaminated area, which supports the assumption of the quotient method that exposure of small mammals is a function of the spray application. However, behavioral responses such as avoidance of contamination may be specific to the chemical, species, and habitat.
Factors affecting the development of testis-ova in medaka, Oryzias latipes, exposed to octylphenol
Authors: Gray Michelle A , Niimi Art J , Metcalfe Chris D
Published: March 2010

There are many endocrine-disrupting chemicals in the environment that have the potential to alter the development of sexual characteristics in fish and wildlife. Little is known about the factors that influence the development of an intersex condition in fish. Japanese medaka (Oryzias latipes) were exposed to octylphenol (OP), a known estrogen agonist, during various life history stages to determine the factors that control induction of testis-ova, an intersex condition. In male medaka exposed to OP (100 μg/L) beginning at 1, 3, 7, 21, and 35 d posthatch, the incidence of testis-ova at 100 d posthatch was highest in the 3-d posthatch treatment (4 of 14 males) and declined when exposures were initiated with older fry. Exposure to OP (100 μg/L) from hatch for a period of 1 or 2 months did not induce testis-ova, but exposure for 3 months resulted in 3 of 50 males developing this condition. Exposures of adult male medaka to OP (200 and 300 μg/L) for either 18 or 36 d resulted in only one testis-ova in a male fish exposed for 36 d to the highest nominal concentration. In addition to testis-ova, male medaka exposed to OP developed testicular fibrosis. Overall, these data indicate that prolonged exposure of male medaka to an estrogen agonist beginning around the period of gonadal differentiation is optimal for the development of testis-ova, but this intersex condition can be induced when exposure begins at later life stages.
Arsenate sensitivity in ericoid and ectomycorrhizal fungi
Authors: Sharples Jade M , Meharg Andrew A , Chambers Susan M , Cairney John W.G
Published: March 2010

Isolates of the endomycorrhizal fungus Hymenoscyphus ericae and the ectomycorrhizal fungus Hebeloma crustuliniforme from soils uncontaminated with AsO3−4, were compared with regard to their sensitivity to AsO3−4 in solution culture. When grown 4 4 in liquid media amended with a range of AsO3−4 concentrations, H. ericae demonstrated reduced sensitivity to AsO3−4 compared to H. crustuliniforme. The concentrations causing 50% inhibition of growth (EC50) were 1.33 mol/m3 and 0.33 mol/m3, respectively, for H. ericae and H. crustuliniforme. The compound AsO3−4 is a PO3−4 analogue for the plasmalemma PO3−4 transporter. The presence of PO3−4 in the media at high concentrations ameliorated the toxic effects of AsO3−4 in both the ericoid and ectomycorrhizal fungi. This could be due to both suppression of the PO3−4 transporter under high phosporus status and competition of PO3−4 with AsO3−4 for the transport protein. The kinetics of AsO3−4 influx in H. ericae and H. crustuliniforme were also investigated. Hymenoscyphus ericae demonstrated a high Km value, 0.071 mol/m3, consistent with values obtained for AsO3−4 -tolerant plants. We suggest that the high Km value may be a mechanism used by H. ericae to express reduced AsO3−4 sensitivity. The ecological significance of this reduced sensitivity is also discussed.
Temperature dependence of Henry's law constants of thirteen polycyclic aromatic hydrocarbons between 4°C AND 31°C
Authors: Bamford Holly A , Poster DIanne L , Baker Joel E
Published: March 2010

An understanding of the temperature dependence of the Henry's law constant for organic contaminants is critical when modeling the transport and fate of these contaminants in the environment. The Henry's law constants for 13 polycyclic aromatic hydrocarbons (PAHs) were experimentally determined between 4 and 31°C using a gas-stripping apparatus. The Henry's law constants ranged between 0.02 ± 0.01 Pa m3/mol for chrysene at 4°C and 73.3 ± 20 Pa m3/mol for 2-methylnaphthalene at 31°C. The temperature dependence of each PAH was modeled using the van't Hoff equation to calculate the enthalpy and entropy of phase change. For nine of the PAHs, the present study reports the first experimental measured temperature dependence of their Henry's law constant. The enthalpies of phase change ranged between 35.4 ± 1.9 kJ/mol for 1-methylphenanthrene and 100 ± 8 kJ/mol for chrysene. These data can be used to extrapolate Henry's law values within the experimental temperature ranges. For all PAHs except benzo[a]fluorene, the temperature dependence can be predicted within a relative standard error <10%.
Effects of chronic, low concentrations of dietary methylmercury on the behavior of juvenile great egrets
Authors: Bouton Shannon N , Frederick Peter C , Spalding Marilyn G , McGill Heather
Published: March 2010

We measured the behavioral effects of methylmercury on 16 great egret chicks (Ardea albus) in a captive dosing experiment. Birds were randomly divided into a control group and groups that received 0.5 or 5 mg methylmercury chloride per kilogram of food at between 12 and 105 d of age. We recorded activity levels, maintenance behavior, and foraging efficiency and determined that mercury affected activity and maintenance behavior. Birds dosed with 5 mg/kg became severely ataxic and were euthanized by 12 weeks of age. We found that, during the postfledging period, there were no differences between low-dose and placebo birds in time required to capture live fish in pools or in efficiency of capture. We did find that low-dose birds were less likely to hunt fish. Our results suggest that, at the 0.5 mg/kg concentration in food, there are significant effects of methylmercury on activity, tendency to seek shade, and motivation to hunt prey.
Test chambers and test procedures for in situ toxicity testing with zooplankton
Authors: Pereira Anabela Maria Maia , da Maia Soares Amadeu Mortágua Velho , Gonçalves Fernando , Ribeiro Rui
Published: March 2010

Ecotoxicity assessment is usually done by classical tests under controlled conditions. However, field situations may not be accurately predicted by laboratory testing. In situ testing is a pertinent way for assessing the ecological relevance of laboratory bioassays. The objectives of this study were to develop an in situ test chamber and respective test protocols suitable for ecotoxicity testing with zooplankton and to evaluate the use of laboratory protocols (water column and solid phase) by comparing results obtained under controlled conditions with in situ results at an aquatic system receiving acid mine drainage. At the most contaminated stations and at the reference stations, good agreement was found between in situ and classical testing. At intermediate stations, in situ toxicity was generally higher than that in classical tests. Sample collection and preservation probably altered actual toxicity, thus emphasizing the need for caution in estimating or extrapolating field effects from laboratory results.
Survival and behavioral responses of larvae of the caddisfly Hydropsyche angustipennis to copper and diazinon
Authors: Van der Geest Harm G , Greve Gerdit D , de Haas Elske M , Scheper Bonnie B , Kraak Michiel H S , Stuijfzand Suzanne C , Augustijn Kees H , Admiraal Wim
Published: March 2010

This study reports on newly developed short-term survival and behavioral tests with larvae of the caddisfly Hydropsyche angustipennis using two model toxicants, copper and diazinon. Mortality of first instar larvae was shown to be a reliable endpoint, and it was demonstrated that H. angustipennis is among the more sensitive aquatic insects in terms of both copper and diazinon. In addition, short-term behavioral responses were found to be indicative of adverse effects of ecologically relevant low doses of copper. Using the tests developed in this study, hydropsychid species are excellent tools for discerning the effects of individual toxicants present in large European rivers, and these species may help in defining the conditions for ecological rehabilitation.
Long-term effects of toxaphene and depuration in lake trout and white sucker in a natural ecosystem
Authors: Delorme Peter D , Lockhart W Lyle , Mills Kenneth H , Muir Derek C G
Published: March 2010

Individuals from lake trout (Salvelinus namaycush) and white sucker (Catastomus commersoni) populations in a small lake located in the Experimental Lakes Area in northwestern Ontario, Canada, were treated with single intraperitoneal injections of toxaphene (7 μg/g or 3.5 μg/g) to better understand its potential effects on fish in their natural environment. Wild fish were captured, tagged, weighed, measured, injected with toxaphene, and released back into the lake. They were subsequently recaptured during spring (white sucker) and fall (lake trout) for the next 5 years. In years 2 and 3 following treatment, fish were spawned to assess reproductive success and survival of their offspring. Survival of adult lake trout and white sucker treated with toxaphene was decreased compared with controls. No changes in growth were evident in either species due to toxaphene treatment. No differences occurred in fertilization rate, total survival, or incidence of deformities in eggs and fry from female lake trout treated with toxaphene. Fertilization rates and survival to swim-up of white sucker eggs and fry from females treated with toxaphene decreased relative to controls in both years. Maternal transfer of toxaphene from female to eggs was observed in both white sucker and lake trout; levels in eggs were much lower than in treated females but were still significantly higher than in controls. Residue analyses showed that depuration of toxaphene was slower than expected, with estimated half-lives of 314 and 793 d in lake trout and white sucker, respectively.
Relationship between polychlorinated biphenyl 126 treatment and cytochrome p4501a activity in chickens, as measured by in vivo caffeine and ex vivo ethoxyresorufin metabolism
Authors: Feyk Lori A , Giesy John P , Lambert George H
Published: March 2010

Cytochrome P4501A (CYP1A) activity is often used as a biomarker of exposure of wildlife to polyhalogenated diaromatic hydrocarbons (PHDHs) and is usually measured ex vivo in liver tissue. A caffeine breath test with radiolabelled substrate (14C-CBT) has been developed to measure in vivo avian CYP1A activity. Research goals were to develop stable isotope methods (13C-CBT), determine dose-response relationships between caffeine N-demethylation (CNDM) and PHDH exposure, and assess the relative utility of the CBT and ex vivo ethoxyresorufin-O-deethylase (EROD) assay. The 13C-CBT methods were developed with 20 chickens (Gallus domesticus). Chickens received three intraperitoneal injections of 0, 1, 5, or 50 μg 3,3′,4,4′,5-pentachloro-biphenyl (PCB 126)/kg body weight, and CNDM was quantified by measurement of 13CO2/12CO2 in expired breath. The 13C-CBT was not as sensitive or specific as the EROD assay as an indicator of PHDH exposure and effect in birds. Constitutive CNDM of great interindividual variability was observed, and the magnitude of induction was greater for EROD activity than for CNDM (approximately 1,000- and 2-fold, respectively). Variability associated with baseline 13CO2/12CO2 ratios in expired breath reduced the sensitivity of the 13C-CBT method.
Toxicity testing of organic chemicals in groundwater polluted with landfill leachate
Authors: Baun Anders , Kløft Lene , Bjerg Poul L , Nyholm Niels
Published: March 2010

A method for assessment of toxicity of nonvolatile organic chemicals contaminants in groundwater polluted with landfill leachate has been evaluated. The biotests utilized were comprosed of an algal growth inhibition test (Selenastrum capricornutum), a daphnia immobilization test (Daphnia magna), and a bacterial genotoxicity test (umuC, Salmonella typhimurium). The feasibility of the selected biotests was investigated for a series of groundwater samples collected along pollution gradients downstreams of two landfills in Jutland, Denmark. Two different approaches were used, direct toxicity testing of whole groundwater samples, and toxicity testing of concentrates obtained by solid-phase extraction. Direct testing of whole groundwater samples produced toxic responses, but the complex sample matrix masked the toxicity of the organic chemical contaminants of interest. Solid-phase extraction was used successfully as an on-site method that eliminated ion toxicity and produced biotest responses that reflected the toxicity of the nonvolatile organic chemical contaminants in the groundwater.
Productivity, diets, and environmental contaminants in nesting bald eagles from the aleutian archipelago
Authors: Anthony Robert G , Miles A Keith , Estes James A , Isaacs Frank B
Published: March 2010

We studied productivity, diets, and environmental contaminants in nesting bald eagles from the western Aleutian Islands, Alaska, USA, during the summers of 1993 and 1994. Productivity on Adak, Tanaga, and Amchitka Islands ranged from 0.88 to 1.24 young produced per occupied site and was comparable to that of healthy populations in the lower 48 United States. However, productivity on Kiska Island was depressed, averaging 0.67 young per occupied site. The lower reproductive success on Kiska was associated with elevated levels of dichlorodiphenyldichloroethylene and other organochlorine pesticides. Many of the organochlorine pesticides were elevated in bald eagle eggs from the four islands, but concentrations of these contaminants and Hg were significantly higher in eggs from Kiska Island than in eggs from the other islands. In contrast, polychlorinated biphenyl concentrations were higher in eggs from Adak, Amchitka, and Kiska (where military facilities have been installed) than in those from Tanaga (which has had little military activity). The most likely source of these contaminants in bald eagles was from their diets, which were variable spatially and temporally. Fish made up most (56%) of the eagles' diet on Adak and Tanaga Islands, followed by birds (25%) and mammals (19%). In contrast, birds comprised the majority (60%) of bald eagle diets on Amchitka and Kiska Islands, followed by mammals (30%) and fish (10%). The high proportion of seabirds in the diet of eagles from Kiska Island could be the major source of organochlorine and Hg contamination. Elevated concentrations of organochlorines in bald eagle eggs from the Aleutian Archipelago was surprising, because of the distance to agricultural areas. The results indicate that these contaminants can be transported long distances and affect wildlife populations in remote and pristine areas. We also discuss potential sources and transport mechanisms of these contaminants to the Aleutian Islands.
Toxicity of retene to early life stages of two freshwater fish species
Authors: Billiard Sonya M , Querbach Kirsten , Hodson Peter V
Published: March 2010

Larval zebrafish (Danio rerio) were exposed for 14 d to graded nominal concentrations of waterborne retene (7-isopropyl-1-methylphenanthrene) from 5 to 336 h postfertilization. Reduced growth, yolk sac edema, and mortality were observed before swim up at nominal concentrations of 320 μg/L and higher in a concentration-dependent manner. Similarly, exposures of rainbow trout (Oncorhynchus mykiss) to retene (32–320 μg/L) for 42 d from the eyed egg stage to hatch and from hatch to the onset of swim up behavior caused exposure-related increases in blue sac disease posthatch. Symptoms included increased activity of cytochrome P4501A (CYP1A) enzymes, yolk sac edema, subcutaneous hemorrhaging, reduced growth, and craniofacial malformations. Chronic exposure to retene resulted in mortality before swim up. Blue sac symptoms were observed in fish exposed to nominal concentrations as low as 32 μg/L, the lowest concentration tested, and fin erosion and opercular sloughing were evident in 100% of retene-exposed swim up larvae. No symptoms were observed in control fish or in fish exposed to acetone, the solvent carrier. The observed pathology resembles the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity to developing stages of fish, and our results suggest that chronic exposure to polycyclic aromatic hydrocarbons may be responsible for recruitment failure associated with pulp mill effluents and oil spills.
Effect of burrowing by the crab helice crassa on chemistry of intertidal muddy sedimentsa
Authors: Williamson R Bruce , Wilcock Robert J , Wise Bridget E , Pickmere Stuart E
Published: March 2010

The chemical environment was measured in vertical and horizontal profiles of cores taken from intertidal sediments that are extensively burrowed by the mud crab Helice crassa. The crab burrows folded the thin (2–5 mm) oxic layer into the sediment, and the burrows appeared to have a strong influence on the concentrations of acid volatile sulfide (AVS), acid-extractable FeII (probably FeCO3 and FeS), FeIII (probably predominantly hydrous ferric oxide FeOOH), and MnII, III, IV and a modest effect on FeS2 but no effect on total organic carbon, total organic nitrogen, or acid-extractable zinc concentrations. The oxic layer was thinner in the burrows than on the sediment surface and showed some minor differences in solid-state chemistry, with higher FeOOH and lower FeS2 concentrations in the burrow walls. Acid volatile sulfide, FeCO3, and FeS2 were found in the oxic layers, presumably because of deposits from crab excavations of deeper anoxic sediments. The chemistry of the bioturbated profile was highly variable, not only because of existing burrows but also because of infilled abandoned burrows. The colors of the sediment profile were strongly related to the concentrations of FeII, AVS, FeIII, Mn, and FeS2. The implications of the observed sediment chemistry to the fate and bioavailability of contaminants is discussed.
Chlordane poisoning of birds in New Jersey, USA
Authors: Stansley William , Roscoe Douglas E
Published: March 2010

During a 16-month period in 1996–97, we documented chlordane poisoning in six species of songbirds and four species of raptors in New Jersey. Noteworthy among these cases are recurring mass mortalities of birds at suburban roosts. At one roost we recovered a total of 425 dead or sick birds comprised of 307 common grackles (Quiscalus quiscula), 104 European starlings (Sturnus vulgaris), and 14 American robins (Turdus migratorius) over a 3-week period in July 1997. Sick birds displayed signs consistent with cyclodiene poisoning, including convulsions, opisthotonos, and excessive vocalization. Brain metabolite residues indicative of chlordane poisoning were found in all 23 specimens analyzed. We believe this to be the largest chlordane poisoning incident reported in the United States. Chlordane poisoning was also diagnosed in nine Cooper's hawks (Accipiter cooperi), a statelisted endangered species. The timing of the Cooper's hawk mortalities coincides closely with the July peak in songbird mortalities, suggesting that the hawks might be feeding on birds debilitated by chlordane. The results of this and other studies suggest that chlordane poisoning of birds may be more common than is currently recognized.
Binding of glyphosate by open-chain polyammonium cations
Authors: Abate Lorenzo , Stefano Concetta De , Foti Claudia , Sammartano Silvio
Published: March 2010

Interaction of glyphosate (N-(phosphonomethyl)-glycine) with six polyamines (ethylendiamine, cadaverine, putrescine, triethylenetetramine, spermine, and tetraethylenepentamine) was studied potentiometrically. Several species of different stoichiometry are formed in the various systems, according to the general formation reaction (where A = amine and glp = glyphosate). The complex species formed are always with r = 1 … (n + 2) (n = maximum degree of protonation of amines). The stability of various complexes is a linear function of charges involved in the formation reaction, and can be expressed as logKij = 0.9(±0.2)ζ (where ζ = i[3 - j]). From the temperature dependence of formation constants, ΔH° (and TΔS°) values have been obtained. Formation percentages of mixed glyphosate—polyammonium cation complexes are relevant also in low concentration conditions, and this means that these species may play a significant role in the speciation of natural fluids containing the reactants.
Estimation of mercury-sulfide speciation in sediment pore waters using octanol—water partitioning and implications for availability to methylating bacteria
Authors: Benoit Janina M. , Mason Robert P , Gilmour Cynthia C
Published: March 2010

The octanol—water partioning of inorganic mercury decreased with increasing sulfide, supporting a model that predicts decreased fractions of neutral Hg—S species with increasing sulfide. These results help explain the decreased availability of Hg to methylating bacteria under sulfidic conditions, and the inverse relationship between sulfide and methylmercury observed in sediments.
Hydroxyatrazine in soils and sediments
Authors: Lerch, Robert N , Thurman, E Michael , Blanchard Paul E
Published: March 2010

Hydroxyatrazine (HA) is the major metabolite of atrazine in most surface soils. Knowledge of HA sorption to soils, and its pattern of stream water contamination suggest that it is persistent in the environment. Soils with different atrazine use histories were collected from four sites, and sediments were collected from an agricultural watershed. Samples were exhaustively extracted with a mixed—mode extractant, and HA was quantitated using high performance liquid chromatography with UV detection. Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were also measured in all samples. Concentrations of HA were considerably greater than concentrations of atrazine, DEA, and DIA in all soils and sediments studied. Soil concentrations of HA ranged from 14 to 640 μg/kg with a median concentration of 84 μg/kg. Sediment concentrations of HA ranged from 11 to 96 μg/kg, with a median concentration of 14 μg/kg. Correlations of HA and atrazine concentrations to soil properties indicated that HA levels in soils were controlled by sorption of atrazine. Because atrazine hydrolysis is known to be enhanced by sorption and pH extremes, soils with high organic matter (OM) and clay content and low pH will result in greater atrazine sorption and subsequent hydrolysis. Significant correlation of HA concentrations to OM, pH, and cation exchange capacity of sediments indicated that mixed—mode sorption (i.e., binding by cation exchange and hydrophobic interactions) was the mechanism controlling HA levels in sediment. The presence of HA in soils and stream sediments at the levels observed support existing hypotheses regarding its transport in surface runoff. These results also indicated that persistence of HA in terrestrial and aquatic ecosystems is an additional risk factor associated with atrazine usage.
Cometabolic mineralization of benzo[a]pyrene caused by hydrocarbon additions to soil
Authors: Kanaly Robert A , Bartha Richard
Published: March 2010

The mineralization of [7-14C]benzo[a]pyrene (BaP) in soil was investigated in response to additions of individual hydrocarbons, defined hydrocarbon mixtures, crude oil, and crude oil fractions. Neither substantial BaP mineralization nor enrichment of BaP degraders occurred in BaP—spiked soil in the absence of a suitable hydrocarbon supplement. Crude oil, the saturated and aromatic class components of crude oil, the distillates heating oil, jet fuel, and diesel fuel supported up to 60% mineralization of 80 μg [7-14C]BaP per gram of soil in 40 d. Neither single hydrocarbons nor defined hydrocarbon mixtures containing normal and branched alkanes, alicyclics, and aromatics supported comparable BaP mineralization. Evolution of 14CO2 occurred after lag periods characteristic to specific petroleum products and their concentrations. Time required for microbial proliferation, hydrocarbon toxicity, and competitive inhibition might have contributed to these lag periods, but the complete inhibition of BaP mineralization by dieselfuel vapors pointed to a dominant role of competitive inhibition. A lack of radiocarbon incorporation into soil biomass from [7-14C]BaP indicated that at least the initial steps of BaP biodegradation in soil were cometabolic in nature. Suitable hydrocarbon mixtures not only supported BaP mineralization by serving as primary substrates, but also enhanced BaP bioavailability by dissolving this hydrophobic solid.
Movement and fate of residual mineral oil contaminants in bioremediated soil
Authors: Angehrn Daniel , Schluep Mathias , Gälli René , Zeyer Josef
Published: March 2010

After the bioremediation of soils contaminated with mineral oil products, residual contaminants (designated as total solvent extractable material [TSEM]) remain therein. Since limited information is available about the movement and fate of these residual contaminants in the environment, the potential environmental hazards are difficult to assess. The aim of this study was to identify and quantify the relevant transport and transformation processes of the residual contaminants in bioremediated soil such as volatilization, leaching, and further biodegradation and to conduct a mass flow analysis for the TSEM in bioremediated soil for the first year after application as top soil. The results indicate that after 1 year, the major portion (93%) of the TSEM can be recovered in the top soil and 7% of the TSEM was lost. The majority of the total losses (>98%) was due to transformation processes (biodegradation and aging effects), while small amounts escaped into the atmosphere (0.08%), plant uptake was negligible, (<0.001%) and leaching, identified as the major transport process, accounted for only small effects (1.7%).
Comparative toxicity of ammonium and nitrate compounds to pacific treefrog and african clawed frog tadpoles
Authors: Schuytema Gerald S , Nebeker Alan V
Published: March 2010

The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla [Baird and Girard]) and African clawed frog (Xenopus laevis [Daudin]) tadpoles were determined in static—renewal tests. The 10-d ammonium nitrate and ammonium sulfate LC50s for P. regilla were 55.2 and 89.7 mg/L NH4-N, respectively. The 10-d LC50s for X. laevis for the three ammonium compounds ranged from 45 to 64 μg/L NH4- N. The 10-d sodium nitrate LC50s were 266.2 mg/L NO3-N for P. regilla and 1,236.2 mg/L NO3-N for X. laevis. The lowest observed adverse effect level (LOAEL) of ammonium compound based on reduced length or weight was 24.6 mg/L NH4-N for P. regilla and 99.5 mg/L NH4-N for X. laevis. The lowest sodium nitrate LOAELs based on reduced length or weight were <30.1 mg/L NO3-N for P. regilla and 126.3 mg/L NO3-N for X. laevis. Calculated un—ionized NH3 comprised 0.3 to 1.0% of measured NH4-N concentrations. Potential harm to amphibians could occur if sensitive life stages were impacted by NH4-N and NO3-N in agricultural runoff or drainage for a sufficiently long period.
Evaluation of the annual killifish Nothobranchius guentheri as a tool for rapid acute toxicity screening
Authors: Shedd, Tommy R , Widder Mark W , Toussaint Margaret W , Sunkel Mark C , Hull Eugene
Published: March 2010

This study evaluated the use of Nothobranchius guentheri as a novel organism for rapid acute toxicity screening. A major advantage of the species is that there is no need to maintain a continuous culture to have organisms immediately available for testing. Rather, the embryos are viable under long—term storage conditions and can be hatched within a few hours. The tests require only 24 h with standard laboratory equipment. Sensitivity levels for 11 representative toxicants were comparable to those reported for five of the standard U.S. Environmental Protection Agency test species requiring continuous culture.
Sex—specific vitellogenin production in immature rainbow trout
Authors: Carlson David B , Williams David E
Published: March 2010

Vitellogenin (Vg) was measured in sexually immature rainbow trout (Oncorhynchus mykiss) exposed to 17β-estradiol (E2) in the diet. Mixed—sex populations of trout aged 3, 6, 12, or 18 months were maintained separately and fed E2 at 0.05 or 2.5 mg/kg for 7 d. Females fed E2 at 0.05 mg/kg consistently produced three- to fourfold greater amounts of Vg than similarly aged males. Age- and sex—matched fish fed E2 at 2.5 mg/kg produced equivalent amounts of Vg. Sex differences in Vg production were apparent only at a dose of E2 (0.05 mg/kg) that results in submaximal Vg induction. Our results document the importance of considering the sex of juvenile fish when using Vg production as a marker of xenoestrogen exposure.
An index of effluent aquatic toxicity designed by partial least squares regression, using acute and chronic tests and expert judgements
Authors: Vindimian ÉRIC , Garric Jeanne , Flammarion Patrick , Thybaud Éric , Babut Marc
Published: March 2010

The evaluation of the ecotoxicity of effluents requires a battery of biological tests on several species. In order to derive a summary parameter from such a battery, a single endpoint was calculated for all the tests: the EC10, obtained by nonlinear regression, with bootstrap evaluation of the confidence intervals. Principal component analysis was used to characterize and visualize the correlation between the tests. The table of the toxicity of the effluents was then submitted to a panel of experts, who classified the effluents according to the test results. Partial least squares (PLS) regression was used to fit the average value of the experts’ judgements to the toxicity data, using a simple equation. Furthermore, PLS regression on partial data sets and other considerations resulted in an optimum battery, with two chronic tests and one acute test. The index is intended to be used for the classification of effluents based on their toxicity to aquatic species.
Reactions of resorcinol and its chlorinated derivatives with monochloramine: Identification of intermediates and products
Authors: Heasley Victor L , Alexander Michael B , Deboard Ryan H , Hanley John C , McKee Tawnya C , Wadley Brian D , Shellhamer Dale F
Published: March 2010

An investigation of the reaction of resorcinol (compound 1) and its chlorinated derivatives 4-chlororesorcinol (compound 4), 4,6-dichlororesorcinol (compound 5), and 2,4,6-trichlororesorcinol (compound 2) with monochloramine (NH2Cl) in ether and aqueous solution (pH 7) is reported. NH2Cl reacted with compounds 1, 2, 4, and 5 to give the pentachloro intermediate, 2,2,4,4,6-pentachloro-5-cyclohexen-1,3-dione (compound 3), which underwent ring opening with H2O and loss of CO2 in the presence of NH2Cl to produce the following: 1,1,3,5,5-pentachloro-3-penten-2-one (compound 6), 1,1,1,3,5,5-hexachloro-3-penten-2-one (compound 7), and 1,1,3,5,5,5-hexachloro-3-penten-2-one (compound 8). Compound 6 reacted further with NH2Cl to give compounds 7 and 8; in the presence of NH2Cl, compound 7 rearranged to compound 8. Mechanisms for the preceding reactions are analyzed in detail. Another aspect of the investigation involved a determination of the amounts of chloroform, CHCl3, which is produced from compound 3 with NH2Cl (4%) and with NaOCl (50%). The low production of CHCl3 from compound 3 and NH2Cl is discussed in connection with the probable reactions of compounds 7 and 8 with NH2Cl and H2O.
Influence of dissolved organic matter on the toxicity of copper to Ceriodaphnia dubia: Effect of complexation kinetics
Authors: Kim Sang Don , Ma Huizhong , Allen Herbert E , Cha Daniel K
Published: March 2010

The reaction kinetics of copper interaction with dissolved organic matter (DOM) in water were studied in order to determine the effect of equilibration period on the toxicity of copper to aquatic organisms. The changes in physical and chemical forms of the copper during four reaction times were examined in four completely mixed reactors in series; the bioavailability of the copper as a function of these new forms was then determined with a flow-through bioassay system, using Ceriodaphnia dubia as a test organism. This study showed that the toxicity of copper to C. dubia decreased with increasing copper-DOM reaction time, which demonstrated that the copper reaction rate with dissolved organic components in the test water was slow. The toxicity of copper to C. dubia was closely related to the measured free-copper concentration (Cu2+) rather than to the total copper concentrations, a fact that supports the free ion activity model. We found that the LC50 of copper for C. dubia increased (i.e., toxicity decreased) linearly with increasing total available binding sites. Although a similar trend was observed in both natural DOM and commercial humic acid, our results indicated that for a given copper-organic carbon ratio, copper binds more strongly to humic acid than to the natural DOM. This difference may be attributed to the greater copper binding affinity of humic acid (greater than that of other metal-binding organic fractions present in DOM, i.e., fulvic acid).
Concentration, distribution, and bioavailability of mercury and methylmercury in sediments of Baltimore Harbor and Chesapeake Bay, Maryland, USA
Authors: Mason Robert P , Lawrence Angie L
Published: March 2010

For the Chesapeake Bay, sediments in regions such as Baltimore Harbor have total mercury (Hg) concentrations that exceed environmental effects guidelines. However, fish concentrations do not appear elevated. Indeed, the factors controlling the transfer of sedimentary Hg, especially as monomethylmercury (MMHg), the most bioaccumulative form of Hg, to these aquatic organisms are poorly understood. To examine this, we have investigated the distribution and bioavailability of Hg and MMHg to benthic organisms in Baltimore Harbor and the Chesapeake Bay, in Maryland, USA. The results discussed here show that sediment concentration for both total Hg and MMHg covaries with sediment organic content and that this parameter is a better predictor, for surface sediments, of concentration than iron content, acid volatile sulfide (AVS), or other factors. Furthermore, correlations between inorganic Hg and MMHg in benthic biota with sediment levels suggest that variation in the bioaccumulation factor (SBAF) for invertebrates is best explained in terms of sediment organic content. Thus, the results from this study emphasize the importance of organic matter in regions removed from point source input in controlling both the concentration and bioavailability of MMHg to organisms. Because of the exponential nature of the SBAF/organic content relationship, there is a nonlinear organism response to MMHg in sediments that must be considered in any estimation of the toxic effect of sediment MMHg. Also, as a result of the decoupling between total Hg and MMHg concentration and bioavailability in surface sediments, any remediation evaluation of bioavailability and/or toxicity that is based only on total Hg concentration is unlikely to provide a reliable prediction.
Biodegradation rates of separated diesel components
Authors: Olson Jennifer Jean , Mills Gary L , Herbert Bruce Eric , Morris Pamela J
Published: March 2010

Three hydrocarbon classes (n-alkanes, branched and cyclic alkanes, and aromatics) were separated from diesel fuel and used as hydrocarbon treatments during a 35-d batch culture experiment in which biodegradation rates of the individual classes were quantified and compared with the biodegradation rate of a treatment consisting of a composite of the three fractions. Triplicate batch cultures of each hydrocarbon treatment were sampled on experimental days 0, 3, 7, 15, and 35. The microbial inoculum used in this study was a crude oil-degrading culture isolated from a contaminated soil. As the experiment proceeded, microbial populations were estimated by total heterotrophic plate counts. Hydrocarbon concentrations were quantified by GC with flame ionization detection, and specific compound identification was confirmed by GC-MS. The composite treatment was separated into aliphatic and aromatic fractions before hydrocarbon analysis. After 35 d, the relative biodegradation for each hydrocarbon class was as follows: n-alkanes > aliphatic fraction of composite solution > aromatics > branched and cyclic alkanes > aromatic fraction of composite solution. In the composite treatment, biodegradation of both aromatic and aliphatic fractions was observed during the 35-d study period and thus did not follow a clear pattern of sequential degradation. However, the biodegradation rate for the aromatic fraction was significantly slower than the aliphatic fraction.