bluuebunny/crossref_metadata_2025 huggingface dataset:
Reductive dechlorination of 4-chlororesorcinol by anaerobic microorganisms
Authors: Boyd Stephen A. , Fathepure Babu Z. , Tiedje James M.
Published: March 2010

The anaerobic dechlorination of 4-chlororesorcinol (4-Cl-Res) to resorcinol (1,3-dihydroxybenzene) by fresh anaerobic digester sludge and by an enriched microbial culture was studied. Complete dechlorination of 50 ppm 4-Cl-Res in fresh sludge required about four weeks and occurred without a lag. An anaerobic community capable of degrading 4-Cl-Res was enriched with 4-Cl-Res as the substrate. Dechlorination of 4-Cl-Res by this enrichment occurred at a relatively low rate (0.3 μmol mg−1 d−1) and after a long lag period (three weeks). Addition of yeast extract or trypticase markedly enhanced the rate of dechlorination. The rate increased from 0.3 μmol mg−1 d−1 in the unamended enrichment to 1.1 to 2.6 μmol mg−1 d−1 in cultures amended with 0.1% yeast extract or 0.1% trypticase. Also, the lag period was reduced from approximately three weeks to less than 2 d. The ability to stimulate reductive dechlorination is important because it demonstrates that this process can be enhanced by carbon additions that may lead to practical schemes for fostering detoxication mechanisms in nature.
Mutagenicity of chlorine-substituted furanones and their inactivation by reaction with nucleophiles
Authors: Ishiguro Yasuhisa , Dence Carlton W. , Lalonde Robert T. , Santodonato Joseph
Published: March 2010

The reported high mutagenic potency of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone against Salmonella typhimurium (TA100) was confirmed in the determined value of 6,300 net revertants/nmol. Partial inactivation of the furanone by Arochlor 1254-induced rat liver homogenate fraction (S9) was observed. Inactivation by the nucleophiles hydroxide ion, SO2, S2O2/3−, pyrrolidine and glutathione, all in aqueous solutions, was determined and the results compared. Mutagenic reduction was observed for all of the nucleophiles but was most pronounced for glutathione. Inactivation by hydroxide ion was most sensitive in the pH range of 9 to 11, was associated with chloride ion formation and paralleled irreversible ultraviolet spectral change resulting in the loss of the 227 nm absorption maximum and the appearance of a new maximum at 255 nm. Neutral aqueous solutions of the furanone and glutathione were marked by two UV maxima, at 250 and 270 nm, and lacked the aldehydic 1H-NMR signal, which was observed in the spectrum of the neutral solution of the furanone alone and was attributed to the presence of its acyclic tautomeric form. Several other furanones were prepared. Their Ames mutagenicities and those of chlorine-substituted intermediates obtained in the synthesis of the furanone were determined and compared, and then related to the reported mutagenicities of some 2-chloropropenals.
Fate of dyes in aquatic systems: I. Solubility and partitioning of some hydrophobic dyes and related compounds
Authors: Baughman George L. , Perenich Theresa A.
Published: March 2010

Solubilities and vapor pressures from the literature are combined with calculated octanol/water partition coefficients, Kow, to assess the expected environmental behavior of about 50 dyes. Most of the older disperse dyes (those that have been in use for decades) have solubilities on the order of 10−7 to 10−6 m. This solubility suggests the potential for a 30- to 150-fold concentration enhancement in sediments and bioconcentration of about 1,000 times in the absence of metabolism. The data also indicate that solubilities computed from Kow (estimated by the substituent method) may be significantly overestimated and that the product of subcooled liquid solubility and estimated Kow for disperse dyes is 10 to 100 times smaller than reported for most other compounds.

Henry's law constants calculated from solubility and vapor pressure show that the disperse and vat dyes will be entirely gas-phase-controlled in their rate of volatilization from water and that this process will be extremely slow. No definitive conclusions can be drawn about the behavior of more recently developed disperse dyes. The available physical constants are compiled along with structures, Color Index number, CAS number and names for 80 compounds.
Effects of monocrotophos and fenthion on discrimination acquisition and reversal in northern bobwhite (colinus virginianus)
Authors: Kreitzer J. F. , Fleming W. J.
Published: March 2010

Adult male northern bobwhite (Colinus virginianus) were fed diets containing organo-phosphorus pesticides, and the birds' discrimination acquisition and reversal performance was evaluated. The birds received the pesticide-laced diets continually, beginning 2 d before behavioral testing and ending after the birds completed the test series consisting of an acquisition and 10 reversals. Bobwhites fed a diet containing 0.18 ppm monocrotophos made 118% more errors (p ± 0.05) than did controls during reversals but not during acquisition. The behavior of bobwhites fed diets containing 0.02 and 0.06 ppm monocrotophos was not different from that of controls. Acquisition performance of bobwhites fed a diet containing 7 ppm fenthion was not different (p > 0.05) from that of controls; however, bobwhites fed the fenthion diet made 48% fewer errors (p ± 0.05) in the reversals. When retested after 18 (monocrotophos) and 73 (fenthion) d on clean diets, no residual behavioral effects were detected. Brain cholinesterase activity was inhibited in all treatment groups.
Effects of fumigation with hydrogen fluoride on the loading of [14C]sucrose into the phloem of soybean leaves
Authors: Madkour Samia , Weinstein Leonard H.
Published: March 2010

The effect of gaseous hydrogen fluoride (HF) on the loading of [14C]sucrose into phloem was studied because this response was a possible target site for F inhibition of translocation of photoassimilate in intact soybean plants. The active loading of [14C]sucrose into the minor veins of soybean leaf discs was inhibited by continuously exposing the plants to HF at nominal concentrations of 1, 3 and 5 μg F m−3 for 8 to 11 d under both controlled-environment and field conditions. The data suggest that phloem loading at atmospheric levels of HF greater than approximately 1 μg m−3 was inhibited less in the plants grown and fumigated in the field than in the laboratory.
Biodegradation of NTA and m-cresol in coastal environments
Authors: Palumbo Anthony V. , Pfaender Frederick K. , Paerl H. W.
Published: March 2010

The biodegradation of m-cresol and nitrilotriacetic acid (NTA) by nonadapted natural populations of aerobic heterotrophic bacteria was examined in a coastal environment near Beaufort, North Carolina, over an 18-month period and in synoptic samples from the Mississippi River, its plume and adjacent coastal waters. The uptake kinetics of radiolabeled m-cresol and NTA were measured at a freshwater site, an estuarine site and a high-salinity offshore site. Uptake of both compounds was greatest in the summer, and half-saturation constants and maximum uptake velocities were greater for NTA than for m-cresol. m-Cresol uptake was greatest in the freshwater environment, and NTA uptake was greatest in the estuary where bacterial numbers and activity were also highest. The uptake of both compounds was lowest in the offshore environment where biological activity was lowest. It appears from the spatial patterns in the Newport River estuary and in areas off the Mississippi that m-cresol biodegradation is substantially reduced at increasing salinity but that NTA uptake is not. Only at extremely low concentrations (less than 1 to 10 μg L−1) and only during the warmer portions of the year is biodegradation of m-cresol in freshwater and estuarine environments important in determining its fate. At higher concentrations and in the marine environment, biodegradation by nonadapted populations is slow and other processes, such as adaptation, dilution and mixing, may be more significant in determining the fate of both compounds.
Characterization of agricultural nonpoint pollution: Pesticide migration in a West Tennessee watershed
Authors: Klaine S. J. , Hinman M. L. , Winkelmann D. A. , Sauser K. R. , Martin J. R. , Moore L. W.
Published: March 2010

Pesticide migration from agricultural fields may stress receiving stream ecosystems as well as contaminate ground water. Research was conducted on an 18-ha single-field watershed in west Tennessee to characterize the fate of atrazine during a 12-month period after pesticide application. Rainfall runoff and soil cores were sampled and analyzed for atrazine residues. Total loss of atrazine by runoff accounted for approximately 1.5% of the total atrazine applied. Concentrations as high as 0.25 mg/L were detected in the field discharge. By the fourth storm event after pesticide application, the atrazine concentration was below detection limits (0.1 μg/L). Atrazine loss in the upper 10 cm of soil followed a first-order decay trend, with only 1.88% of the initial concentration remaining 238 d after pesticide application. The mean half-life for atrazine in the upper 10 cm was approximately 21.5 d. Atrazine was detected in the 10- to 20-cm soil level after the first rainfall. Atrazine was not detected below 20 cm at any sampling date during the 238 d of the study.
Screening and biomonitoring of industrial effluents using phytotoxicity tests
Authors: Wang Wuncheng , Williams Judson M.
Published: March 2010

The use of phytotoxicity (higher plant) tests as a part of ecotoxicology is relatively underdeveloped. The objective of this study was to evaluate phytotoxicity tests for screening and biomonitoring complex effluent samples. Mortality tests using common duckweed and seed germination tests were conducted using eight effluent samples collected from three industrial sources. Duckweed plants were found to be extremely sensitive to two effluents, with nearly 100% mortality occurring. Duckweed plants in some samples showed lesions (breakup of colony structure) and loss of green pigments (chlorosis); others showed localized dead tissues (necrosis). Six kinds of seeds were tested: cabbage, cucumber, millet, Japanese millet, rice and wheat. Cabbage and millet seeds were the most sensitive. The germination of these seeds was 100% inhibited in some samples. The results suggest that phytotoxicity tests with higher plants have potential for use in the biomonitoring of industrial effluents because of their simplicity, sensitivity and cost-effectiveness.
Sorption behavior of tributyltin on estuarine and freshwater sediments
Authors: Unger Michael A. , MacIntyre William G. , Huggett Robert J.
Published: March 2010

Equilibrium sorption of tributyltin chloride (TBT) was measured on selected estuarine and freshwater sediments. Isotherms from 24-h equilibrations were linear, with sorption coefficients between 1.1 × 102 and 8.2 × 103 L/kg. The similarity of sorption and desorption coefficients for these sorbates showed that TBT sorption is reversible. Sorption coefficients decreased with increasing salinity and varied by a factor of 2 over the salinity range 0 to 34%. Desorption kinetics indicated an initial fast rate followed by a slower rate of desorption, similar to published data for metal ions and hydrophobic organic molecules on sediments. Water and sediment concentrations of TBT at locations in the Chesapeake Bay system were used to calculate apparent sorption coefficients, which generally agreed with laboratory-measured sorption coefficients. Exceptionally high apparent sorption coefficients were found near areas of high vessel activity and may be due to TBT paint chips in the sediment.
Biodehalogenation: Active site versus enzymatic and whole cell rates with cytochromes P-450
Authors: Castro C. E. , Yokoyama W. , Belser N. O.
Published: March 2010

The products stoichiometry and kinetics of the reduction of trichloronitromethane (chloropicrin), bromotrichloromethane, carbon tetrachloride, ethylene dibromide and 1,2-dibromo-3-chloropropane by iron(II) deuteroporphyrinlX, rat liver P-450PB and P-450 cam were compared with the reactions of reduced liver microsomes and the whole-cell model Pseudomonas putida (PpG-786). The polyhalomethanes in all cases undergo quantitative reductive hydrogenolysis The vicinal halides are Quantitatively converted by all P-450 components to the corresponding olefins

In contrast to the steric retardation of the rates exhibited by P-450 cam, the rate constants for the mammalian enzyme were the same as those obtained for the heme in homogeneous solution. Microsomal reactions followed the same general reactivity patterns but on a much compressed scale. The whole-cell conversions are apparently controlled in part by permeation; thus the microbial dehalogenation processes proceed at much slower rates than the actual chemistry that occurs at the active site. The results establish that the reductase capacities of widely divergent P-450 cytochromes are consistent with the chemistry and mechanisms established for hemes in homogeneous solutions. Both microorganisms and mammals have the capacity to dehalogenate these substances.
Interpretation of confidence intervals for median effective dose estimates
Authors: Kaiser Mark S.
Published: March 2010

Philosophical considerations in the interpretation of probability can confuse the meaning of interval estimates. Most techniques for calculating interval estimates for the median effective dose (LC50) have been developed under a Neyman-Pearson probability structure, which requires interpretation in terms of asymptotic mathematics. Fiducial probability, designed to allow the inductive use of a single experiment, fails to resolve this major difficulty in interpretation. In the evaluation of LC50 estimators, care should be exercised to ensure correct identification of random variables, consistent partitioning of sources of variability and proper choice of criteria for comparing estimators. Despite the difficulties raised by these issues, the calculation of interval estimates in short-term toxicity testing remains an important benchmark in assessing the potentially harmful effects of chemical compounds in the environment.
Effect of food availability on the acute toxicity of four chemicals to mysidopsis bahia (mysidacea) in static exposures
Authors: Cripe Geraldine M. , Ingley-guezou Anne , Goodman Larry R. , Forester Jerrold
Published: March 2010

The effect of nutritionally deficient Artemia nauplii on the growth of the mysid, Mysidopsis bahia, were evaluated in static systems. When Artemia nauplii with or without highly unsaturated fatty acid 20:5 ω 3 were fed to 24‒h‒old M. bahia there was no difference in growth of mysids on either ration after 96 h of feeding. A study comparing amount of available food in static systems necessary for good survival and growth indicated that rations of 5, 10 or 30 Artemia per mysid per day (A/m/d) were different from 50, 70, 90 and 110 A/m/d as measured by dry weight. Static acute 96‒h tests were conducted with ≤24‒h‒old Mysidopsis bahia using either carbophenothion, cypermethrin, malathion, or 4‒(tert‒octyl)phenol. For each chemical, two replicate tests were conducted simultaneously with each of three rations of food provided. The rations chosen were 10 A/m/d, providing survival with minimal growth, a midpoint ration (60 A/m/d), and 110 A/m/d, clearly in excess of that necessary for good survival and growth. Only LC50s obtained in tests using 10 A/m/d were significantly different from other test results. These tests indicate that lack of food does adversely affect results of mysid static tests. In addition, excess food has the potential to reduce dissolved oxygen to nearly unacceptable concentrations.
Aquatic toxicology of the pyrethroid insecticides: Neurotoxicology of pyrethroids: Single or multiple mechanisms of action?
Authors: Clark Marshall J. , Brooks Matthew W.
Published: March 2010

It has been almost 25 years since the classic studies first described the pyrethroid mode of action on voltage—dependent sodium channels. In the interval that followed, this electrophysiological approach has been enlarged upon using a variety of preparations with essentially the same result. Thus, there is little disagreement that pyrethroids have an action at or near the sodium channel in the nerve. Recently, a number of additional mechanisms have been suggested, including the perturbation of the voltage—dependent calcium channels. Using a functional bioassay that consists of a calcium—dependent, potassium—stimulated pulsed release of norepinephrine from rat brain synaptosomes, Type II pyrethroids caused a substantial enhancement of norepinephrine release that was not apparent when Type I pyrethroids were used. The ED50 dose of deltamethrin that resulted in half—maximal enhanced norepinephrine release (i.e., 2.9 × 10−9 M) correlated well with the ED50 dose of deltamethrin that resulted in half—maximal enhanced 45Ca uptake (i.e., 2.4 × 10−9 M). Norepinephrine release was only partially blocked by tetrodotoxin and a calcium channel antagonist, D595. Deltamethrin enhanced norepinephrine release in the presence of tetrodotoxin but was unable to enhance release in the presence of D595. These results are supportive of a highly sensitive action of Type II pyrethroids at presynaptic nerve terminals in the central nervous system and of the involvement of voltage—dependent calcium channels.
Dorsal gill incision: A simple method for obtaining blood samples in small fish
Authors: Watson Carl F. , Baer Kevin N. , Benson William H.
Published: March 2010

Hematological parameters may provide valuable diagnostic information in assessing the sublethal toxicological effects of waterborne contaminants in fish. However, because of size limitations, the use of hematological evaluations in small fish has been restricted. In addition, only a few techniques have been reported in the literature for obtaining blood from small fish. The present investigation was undertaken to evaluate a simple and rapid technique, dorsal gill incision, for collecting blood samples from small fish. Blood samples were obtained from bluegill sunfish, Lepomis macrochirus, by caudal peduncle transection and dorsal gill incision. Analysis of the coefficients of variation in whole blood parameters indicated that the variability in samples was reduced with the dorsal gill incision technique. Plasma aspartate aminotransferase and creatine kinase levels in caudal peduncle transection samples were significantly elevated (p < 0.05) above the levels obtained by dorsal gill incision. Dorsal gill incision is proposed as an easy and rapid alternative to currently available methods for blood sampling in small fish.
Comparisons of single-species, microcosm and field responses to a complex effluent
Authors: Pontasch Kurt W. , Niederlehner B. R. , Cairns John
Published: March 2010

Short-term, single-species toxicity tests are used to identify, regulate and monitor the discharge of problem effluents into receiving ecosystems. The ability of single-species tests to protect entire ecosystems has been questioned, and microcosm tests have been proposed as additional tools for reducing uncertainty in environmental risk assessment. We compared responses to a complex effluent in microcosms of indigenous macroinvertebrates and protozoans with responses observed in acute tests with Daphnia magna, Ceriodaphnia dubia and Pimephales promelas and in chronic survival and reproductive tests with C. dubia. The predictive utility of these various tests was then evaluated in relation to observed effects in the receiving stream. The acute LC50s (percent effluent) from the acute tests were 63.1 for P. promelas, 18.8 to 31.3 for D. magna and 54.7 for C. dubia. Results from 7-d chronic tests indicated that C. dubia survival was significantly (p ≤ 0.05) affected at 30% effluent and that reproduction was affected at concentrations ≥3% effluent. In the protozoan microcosms, community composition was significantly (p ≤ 0.05) changed at 1.0%, while protozoan species richness was significantly reduced at 3.0% effluent. In the macroinvertebrate microcosms, mayflies were the only macroinvertebrates adversely affected by the effluent. Four mayfly taxa showed significant (p ≤ 0.05) reductions in density in the 1.0% treatment and four others were significantly reduced at 10.0%; however, some chironomids had significant increases in density at 0.1% and above. Microcosm responses corresponded well with observed effects in the field. The microcosms correctly predicted which indigenous organisms would be lost and which would be stimulated at various ambient concentrations of the effluent.
Development and evaluation of a novel marine sediment pore water toxicity test with the polychaete dinophilus gyrociliatus
Authors: Carr Robert Scott , Williams John W. , Fragata Carlos T. B.
Published: March 2010

As a candidate for future use in the National Status and Trends Program, a novel marine sediment pore water toxicity test procedure was developed and evaluated. The test procedure involves obtaining sediment pore water with a pressurized squeeze-extraction device, and then conducting a life-cycle toxicity test with the polychaete Dinophilus gyrociliatus. Recent studies have demonstrated that for certain nonpolar organic contaminants, the key route of exposure is from the interstitial (pore) water. Sediment samples were collected from 15 different stations in the San Francisco Bay area with varying amounts of contamination. The results from the San Francisco study and other studies conducted during the development of this test procedure are reported.
Interaction of humic acid with selected trace metals: Influence on bioaccumulation in daphnids
Authors: Stackhouse R. Allan , Benson William H.
Published: March 2010

The influence of humic acid (HA) on the bioaccumulation of Cd, Cr VI and two forms of Cr III was evaluated using a common freshwater cladoceran, Daphnia magna. HA (0.5, 5 and 50 mg/L) had a much greater influence on the bioaccumulation of Cd and Cr III than of Cr VI. At only one time point (96 h) did the 50 mg/L HA significantly decrease the bioaccumulation of Cr VI. The remaining concentrations of HA (0.5 and 5 mg/L) had no influence on Cr VI bioaccumulation. However, with both forms of Cr III, 50 mg/L HA significantly decreased bioaccumulation, while 0.5 and 5 mg/L HA concentrations either decreased or had no influence on bioaccumulation. The results of the Cd-HA interaction were much more variable than those obtained with Cr VI or Cr III. The bioaccumulation of Cd was increased, decreased or not influenced by HA, depending on the concentration of HA and the exposure period examined.
Octanol/water partition coefficients and bioconcentration factors of chloronitrobenzenes in rainbow trout (salmo gairdneri)
Authors: Niimi A. J. , Lee H. B. , Kissoon G. P.
Published: March 2010

The relationship between octanol/water partition coefficient (Kow) and bioconcentration factor (BCF) of 14 monochloro- to pentachloronitrobenzenes were examined in rainbow trout through waterborne and dietary exposure studies. The results indicated BCF was not significantly correlated with Kow for this chemical group. The role of chemical half-lives and chemical absorption efficiencies are examined as factors that could explain why the BCF of some chemical groups are lower than predicted.
Variability associated with identification of toxics in national pollutant discharge elimination system (npdes) effluent toxicity tests
Authors: Dorn P. B. , Rodgers J. H.
Published: March 2010

Effluent toxicity testing is a routine National Pollutant Discharge Elimination System (NPDES) permit monitoring requirement for many municipal and industrial dischargers. Effluent toxicity compliance limits are being set in an increasing effort to limit discharge of toxics into U.S. water bodies. To that end, hazard assessment principles are being applied to limit discharged toxicity based on instream effects as judged by effluent toxicity, fate and exposure. Uncertainty arises in complying with effluent toxicity limits because of a number of factors, including an unacceptably toxic effluent, error in conducting a specified test, test organism health, statistical variability and interferences in the test solution that mask the toxic effect.

Three factors that may influence compliance with toxicity limits and/or identification of toxics are discussed. These factors indicate the need for additional consideration before setting permit limits, determining requirements for toxicity reduction and possibly implementing additional effluent treatment.

Comparisons between reference toxicant data and control mortality showed that reference toxicant data provide an additional control for determining whether effluent toxicity test results are valid and that they can be used to test regulatory compliance. Statistical sampling theory was explored to determine compliance with an effluent toxicity requirement of 80% survival in 100% effluent. Third, several test species were used to determine the causative toxic agents in order to correctly identify toxicity and to separate true toxic effects from interferences in exposures to receiving water.
Fate of dyes in aquatic systems II. solubility and octanol/water partition coefficients of disperse dyes
Authors: Yen Chi-Ping C. , Perenich Theresa A. , Baughman George L.
Published: March 2010

Water solubilities have been measured for 10 disperse dyes that are mostly of recent vintage. The solubilities and octanol/water partition coefficients are used to predict expected concentration factors for sediment and biota. The results show that these newer disperse dyes are likely to have greater potential toward sediment sorption and bioconcentration than older dyes. The data also confirm a previous conclusion that methods for estimating the octanol/water partition coefficient of these dyes give results that are significantly different from measured values. Possible explanations for the difference are discussed.
Photocatalytic degradation of DDT mediated in aqueous semiconductor slurries by simulated sunlight
Authors: Borello Roberta , Minero Claudio , Pramauro Edmondo , Pelizzetti Ezio , Serpone Nick , Hidaka Hisao
Published: March 2010

The degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) by simulated sunlight ( > 340 nm) has been investigated in the presence of aqueous suspensions of semiconductor particulates (TiO2, ZnO, CdS, WO3, α-Fe2O3 and TiO2/5 wt.% Pt). Titanium dioxide appears to be the most effective catalyst; the half-life for the processes is −40 min (at initial DDT concentration 1 mg L−1 and 2 g L−1 TiO2, photon flux 3 × 10−5 einstein/min, over a cell cross-section of 4 cm2).

The near quantitative recovery of chloride ions after long irradiation periods suggests that the end products of the degradative process are CO2 and HCl. To the extent that neither DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) nor DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) were observed by gas chromatographic techniques, the reaction proceeds through hydroxyl radical attack on the aromatic moieties with subsequent ring opening.
Bioavailability of sediment-sorbed and aqueous surfactants toChironomus riparius(midge)
Authors: Pittinger Charles A. , Woltering Daniel M. , Masters Julie A.
Published: March 2010

The bioavailability of sediment-sorbed and soluble fractions of three surfactants were compared in egg hatchability and partial life cycle chronic bioassays with the midge Chironomus riparius. The chemicals tested were linear alkyl (dodecyl) benzene sulfonate (LAS), dodecyl trimethyl ammonium chloride (TMAC) and distearyl dimethyl ammonium chloride (DSDMAC). Midge eggs exposed to ranges of surfactant concentrations in water were monitored for hatching success and posthatch survival. No significant reductions in egg hatching were observed at the highest concentrations tested: 18.9 mg/L LAS, 21.5 mg/L DSDMAC and 15.4 mg/L TMAC. Newly hatched larvae were more sensitive than eggs; respective 72-h LC50 concentrations (48-h for TMAC) were 2.2, 11.3 and 14.6 mg/L. In partial life cycle chronic bioassays in sediment/water test systems, percentages of winged adults emerging after continuous exposure of larvae and pupae to doses of each surfactant were determined. Exposure concentrations in sediment, interstitial water and overlying water were monitored by 14C liquid scintillation counting. Lowest observed effect concentrations (LOECs) of sediment-spiked surfactants were 319 to 993 μg/g (dry weight) LAS, 876 to 2,708 μg/g DSDMAC and >3,084 μg/g TMAC (highest concentration tested). Corresponding no observed effect concentrations (NOECs) were 319 μg/g LAS, 876 μg/g DSDMAC and 3,084 μg/g TMAC. The NOECs are approximately 100, 1,000 and 10,000 times greater than respective NOECs of the solubilized materials, and exceed levels of these materials measured in the environment. The results indicated that adsorption onto sediment significantly mitigates surfactant bioavailability to Chironomus.
Measuring the acute toxicity of estuarine sediments
Authors: Dewitt Theodore H. , Swartz Richard C. , Lamberson Janet O.
Published: March 2010

Estuarine sediments frequently are repositories and sources of anthropogenic contaminants. Toxicity is one method of assessing the environmental quality of sediments, yet because of the extreme range of salinities that characterize estuaries few infaunal organisms have both the physiological tolerance and sensitivity to chemical contaminants to serve in estuarine sediment toxicity tests. We describe research on the estuarine burrowing amphipod, Eohaustorius estuarius Bosworth, 1973, whose survival was ≥95% in control sediments across a 2 to 28% salinity range over 10-d periods. E. estuarius also was acutely sensitive to low sediment concentrations of the polycyclic aromatic hydrocarbon, fluoranthene (LC50 ≈︁ 10.6 mg/kg), and its sensitivity to fluoranthene was not affected by salinity. E. estuarius was almost as sensitive as Rhepoxynius abronius to fluoranthene and to field-collected sediments from Puget Sound urban and industrial bays. E. estuarius was also more tolerant of very fine, uncontaminated sediments than R. abronius. Furthermore, E. estuarius was more sensitive to sediments spiked with fluoranthene than the freshwater amphipod, Hyalella azteca. E. estuarius, and possibly other estuarine haustoriid species, appears to be an excellent candidate for testing the acute toxicity of estuarine and marine sediments.
Use of mixed-function oxygenases to monitor contaminant exposure in wildlife
Authors: Rattner Barnett A. , Hoffman David J. , Marn Carolyn M.
Published: March 2010

This overview examines the utility of mixed-function oxygenase (MFO) enzymes as a bio-effects monitor for wildlife (amphibians, reptiles, birds and mammals) in view of their widespread use as indicators of contaminant exposure in aquatic invertebrates and fish. Phylogenetic trends in MFO activity, toxicological implications of induction and the relationship between contaminant exposure and MFO activity are discussed. Field studies using avian embryos and hatchlings suggest that MFO induction has utility for documenting contaminant exposure; however, findings in adult birds and mammals are equivocal. Age, sex and season are sources of variation that require consideration when undertaking field trials. Further understanding of MFO inducibility among species and application of recently developed analytical techniques including quantification of specific cytochrome P-450 isozymes are warranted.
Flavin-sensitized photodecomposition of anilines and phenols
Authors: Larson Richard A. , Ellis David D. , Ju Hui-Lin , Marley Karen A.
Published: March 2010

Riboflavin, a known photosensitizer, when initially added at 5 m̈m to solutions of added phenols or anilines (structurally related to common environmental contaminants) greatly accelerated the rate of their loss in the presence of light. The sensitized photolysis rates increased in the absence of oxygen, suggesting a mechanism involving direct energy or electron transfer between flavin excited states and acceptor molecules. A preliminary kinetic model was developed to calculate loss rates. Riboflavin itself was rapidly converted in aqueous solution by Pyrex-filtered mercury arc light to products that had variable efficiencies as sensitizers.
A method for determining gut uptake efficiencies of hydrophobic pollutants in a deposit-feeding clam
Authors: Lee Ii Henry , Boese Bruce L. , Randall Robert C. , Pelletier Judy
Published: March 2010

Deposit-feeding invertebrates select particles for ingestion that are richer in organic carbon, and thus higher in pollutant concentration, than the mean values of bedded sediment. To estimate the ingested pollutant dose, a method was developed that uses the enrichment of the total organic carbon concentration (TOC) of the feces compared to the TOC of the bedded sediment as a measure of pollutant enrichment in the ingested particles. The deposit-feeding clam Macoma nasuta (Conrad) was exposed for 7 d in clamboxes to either bulk or fine sediment fractions that varied in TOC. Feces were collected and the TOC of sediment and feces estimated. The TOC of the feces was corrected for the carbon lost during digestion. The selectivity index (SI), the ratio between the corrected TOC of the feces and TOC of the bedded sediment, was determined to be 4.36 and 1.72 for the bulk and fine sediment fractions, respectively. The SI was then applied to data from a companion study in which M. nasuta was exposed to hexachlorobenzene (HCB) dosed sediment. The efficiency of gut uptake of HCB sorbed on ingested sediment ranged from 38 to 56%, with the lower value the more reliable. The effects of selection by deposit feeders for organically rich, high pollutant particles needs to be considered in experiments measuring the bioavailability of sediment-sorbed pollutants or in experiments attempting to determine the routes of pollutant uptake.
Risks of toxic contaminants to exploited fish populations: Influence of life history, data uncertainty and exploitation intensity
Authors: Barnthouse Lawrence W. , Suter Glenn W. , Rosen Aaron E.
Published: March 2010

We investigated three aspects of the use of toxicity test data for population-level risk assessment: (a) the influence of life history characteristics on vulnerability to contaminant-induced stress, (b) the importance of test data availability and (c) the influence of exploitation intensity. We quantified population-level effects of chronic contaminant exposure by coupling standard toxicity test data to matrix-type population models derived from long-term field studies of the Gulf of Mexico menhaden (Brevoortia patronus) and Chesapeake Bay striped bass (Morone saxatilis) populations. We used statistical regressions to quantify the uncertainty inherent in using test data ranging from life cycle tests to quantitative structure-activity relationships (QSARs) to estimate effects of contaminants on the survival and reproduction parameters of the population models.

We found that because of differences in life history, menhaden and striped bass differ in terms of their capacity to sustain the same level of contaminant-induced mortality. Changes in exploitation intensity affect the responses of both populations to the same level of additional contaminant-induced mortality. However, the quantitative effects of both factors are negligible compared to the uncertainty introduced by estimating long-term effects from short-term tests or QSARs. Our results suggest that consideration of life history may be important primarily for site-specific assessments. For screening-level assessments, the substantial differences in uncertainty associated with different types of test data are of much greater concern.
Toxicity of organic selenium in the diet to chinook salmon
Authors: Hamilton Steven J. , Buhl Kevin J. , Faerber Neil L. , Bullard Fern A. , Wiedmeyer Raymond H.
Published: March 2010

The toxicity of two organoselenium diets was evaluated in 90- to 120-d partial life cycle tests with two life stages of chinook salmon (Oncorhynchus tshawytscha Walbaum). One of the diets contained fish meal made from high-selenium mosquitofish (Gambusia affinis Baird and Girard) collected from the selenium-laden San Luis Drain, California (here termed SLD diet) and the other contained meal made from low-selenium mosquitofish (collected from a reference site) fortified with selenomethionine. A 90-d study was conducted with swim-up larvae in a water-simulating dilution of San Luis Drain water in a standardized fresh water; and a 120-d study was conducted with fingerlings 70-mm long in a water of similar quality but prepared with a standardized brackish water. After 90 d of exposure in the freshwater study, survival was reduced in fish fed ≥9.6 μg Se/g of either diet, and growth was reduced in fish fed ≥5.3 μg Se/g of SLD diet or ≥18.2 μg Se/g of selenomethionine diet. Reduced fish growth, whole-body concentrations of selenium and survival were strongly correlated to concentrations of selenium in both diets. After 120 d of exposure in the brackish-water study, survival was unaffected but growth was reduced in fish fed ≥18.2 μg Se/g of SLD diet or 35.4 μg Se/g of selenomethionine diet. After 120 d of dietary exposure, survival during a 10-d seawater challenge test was reduced in fish fed 35.4 μg Se/g of either diet. In this second dietary study, concentration—response relations were observed in both dietary treatments between the dietary concentrations of selenium and all three characteristics — fish growth, whole-body concentrations of selenium and survival in seawater.
Mobility and persistence of alachlor, atrazine and metolachlor in plainfield sand, and atrazine and isazofos in honeywood silt loam, using field lysimeters
Authors: Bowman Bruce T.
Published: March 2010

Mobility and persistence of commercial formulations of alachlor, metolachlor and isazofos were studied under two moisture regimes using 75 × 15 cm field lysimeters. Formulated atrazine was also applied to each lysimeter for reference purposes. Alachlor- and metolachlor-treated lysimeters were packed with Plainfield sand, while Honeywood silt loam was used to pack isazofos-treated lysimeters. Effluent was monitored for each chemical, and selected cores were sectioned (7 × 10 cm) and analyzed to determine mobility profiles and persistence at weeks 1, 2, 4, 8, 12 and 21. The 50% disappearance times (DT50) for alachlor, atrazine, isazofos and metolachlor were: <1.5, 4, 1.5 and 3 to 4 weeks, respectively. Water application during week 1, following pesticide application, created ponding on Honeywood soil cores, transporting atrazine and isazofos to a maximum 50-cm depth. While isazofos moved no further after week 1, atrazine and desethylatrazine (Des-Atr.) exhibited considerable mobility throughout the study. Ponding on Honeywood silt loam cores produced greater atrazine and Des-Atr. movement than in Plainfield sand cores. Des-Atr. production increased with soil moisture content. Relative mobilities in Plainfield sand were: Des-Atr. ≥ atrazine > metolachlor > alachlor; in Honeywood silt loam: Des-Atr. > atrazine > isazofos.
Effect of fenitrothion on the foraging behavior of juvenile atlantic salmon
Authors: Morgan M.J. , Kiceniuk J. W.
Published: March 2010

Juvenile Atlantic salmon (Salmo salar) were exposed for 7 d to sublethal concentrations of technical grade fenitrothion and an operational formulation containing 11% fenitrothion Foraging behavior of the salmon was then tested in a stream tank Concentrations of 0 02 and 0 16 μl/L of technical grade fenitrothion and the operational formulation containing 0 08 and 0 16 μl/L of fenitrothion caused a significant decrease in the efficiency of the salmon's attack sequence These concentrations, and a concentration of 0 005 μl/L technical grade fenitrothion and 0 004 μl/L fenitrothion in the operational spray, produced a significant decrease in the salmon's reaction distance to prey All concentrations except for 0 004 μl/L fenitrothion in the operational formulation caused a significant decrease in the number of ingestions of prey made by the fish These results suggest that foraging behavior in salmon is impaired by exposure to very low levels of fenitrothion
Comparisons between sediment bioassays and alterations of benthic macroinvertebrate assemblages at a marine superfund site: Commencement bay, Washington
Authors: Becker D. Scott , Ginn Thomas C. , Bilyard Gordon R.
Published: March 2010

Laboratory sediment bioassays and alterations of benthic macroinvertebrate assemblages were evaluated at 43 stations in Commencement Bay, Washington, and at 4 stations in Carr Inlet, Washington (a reference embayment). Three bioassays were evaluated: the amphipod mortality test using Rhepoxynius abronius, the oyster larvae abnormality test using Crassostrea gigas and the Microtox® test using Photobacterium phosphoreum. Alterations of benthic assemblages were determined using numerical classification analysis.

Bioassay responses and alterations of benthic assemblages were closely related to chemical contamination, suggesting that most biological effects resulted from chemical toxicity. Although all three bioassays were reasonably successful in predicting the presence or absence of moderately to severely altered benthic assemblages, considerable differences were found in the ability of the tests to identify only the altered assemblages. The Microtox bioassay successfully identified the highest percentage of altered benthic assemblages. By contrast, the oyster larvae abnormality bioassay falsely predicted the lowest percentage of altered assemblages. Tiered application of results of both the Microtox and oyster larvae tests improved the accuracy with which altered assemblages were identified.
Short Communication: Contribution of the 5-hydroxyl group to the mutagenicity of mucochloric acid
Authors: LaLonde Robert T. , Perakyla Hannu , Cook Gary P. , Dence Carlton W.
Published: March 2010

The sodium borohydride reduction of 3,4-dichloro-5-hydroxy-2(5H)-furanone (mucochloric acid) resulted in the formation of 3,4-dichloro-2(5H)-furanone and 4-chloro-2(5H)-furanone formed in relative amounts of 98 and 2%, respectively. Mucochloric acid and 3,4-dichloro-2(5H)-furanone were assayed together against Salmonella typhimurium (TA100). Mucochloric acid was consistently more mutagenic than 3,4-dichloro-2(5H)-furanone by a factor ranging from 36 to 49 times as established from three determinations of relative mutagenicity. Thus, the hydroxyl group substituted at the 5 position is concluded to have a marked influence on the mutagenicity of a chlorinated 2(5H)-furanone.
Acute toxicity of a complex mixture of synthetic hexachloroethane (HC) smoke combustion products: I. Comparative toxicity to freshwater aquatic organisms
Authors: Fisher Daniel J. , Burton Dennis T. , Paulson Robert L.
Published: March 2010

The acute toxicity of a synthetic hexachloroethane (HC) smoke combustion products mixture to nine freshwater aquatic organisms was determined. Synthetic HC smoke combustion products are a complex mixture containing Zn, Cd, As, Pb, Al, CCl4, C2Cl4, C2Cl6, C6Cl6 and HCl. Juvenile fish exposed to this mixture for 96 h included the fathead minnow, bluegill, channel catfish and rainbow trout. Invertebrates tested for 48 h included the neonate water flea, early young amphipod, midge larva and the mayfly larva. The effect of the mixture on the growth of the green alga Selenastrum capricornutum was also studied.

The dissolved components of the synthetic HC smoke combustion products mixture were found to be quite toxic to a number of freshwater species, especially the algae, rainbow trout and water flea. A test solution containing only 5.6% of a stock mixture of these components caused both an algistatic and algicidal effect on the alga. The rainbow trout and the water flea had 96- and 48-h LC50s of 2.2 and 9.3% of the stock solution, respectively.
Aqueous inputs of mercury to precambrian shield lakes in ontario
Authors: Mierle Greg
Published: March 2010

The concentration of mercury in precipitation and in streams of a central Ontario lake were measured over a one year period. The concentrations in streams were generally very low (<5 ng/L), but during warm periods with low discharge, concentrations often exceeded 20 ng/L in a headwater stream draining a wetland. The concentration in precipitation varied from about 2 to nearly 30 ng/L and exhibited no seasonal pattern. By combining the concentration data with discharge and precipitation depth the inputs of mercury from runoff and direct deposition were estimated. Direct wet deposition accounted for over half of the supply of mercury to the lake. The watersheds retained most of the mercury deposited on them. The presence of wetlands appeared to decrease retention efficiency.
Copper toxicity to Paratya australiensis: I. Influence of nitrilotriacetic acid and glycine
Authors: Daly Helen R. , Campbell Ian C. , Hart Barry T.
Published: March 2010

The relationship between copper speciation and acute toxicity to the Australian freshwater shrimp, Paratya australiensis was determined using a combination of copper ion selective electrode measurements, complexing resins and computer calculations to measure the speciation in test solutions. A number of problems were encountered with the use of the copper ion selective electrode in waters containing added complexing agents.

In solutions containing nitrilotriacetic acid or glycine, uncomplexed copper(II) ions were found to be the most acutely toxic form of copper to the shrimp. However, at least one other species, the singly charged complex (Cu-Glycine)+, also appears to be mildly toxic. The results of this study demonstrate the importance of considering metal speciation when assessing the impact of heavy metals on aquatic organisms.
Acute toxicities of five synthetic pyrethroid insecticides to Daphnia magna and Ceriodaphnia dubia
Authors: Mokry Loretta E. , Hoagland Kyle D.
Published: March 2010

The acute toxicities of four recently developed pyrethroid insecticides (bifenthrin, cyfluthrin, lambda cyhalothrin and tralomethrin) were experimentally compared to the acute toxicity of a first generation pyrethroid (permethrin), in static-flow, 48-h bioassays with Daphnia magna and Ceriodaphnia dubia. The four new generation pyrethroids exhibited greater toxicity, with LC50s ranging from 0.15 to 1.04 μg/L for D. magna and 0.07 to 0.30 μg/L for C. dubia, in comparison to permethrin with LC50s of 1.25 μg/L for D. magna and 0.55 μg/L for C. dubia. Tralomethrin and cyfluthrin were most toxic to D. magna, with LC50s of 0.15 and 0.17 μg/L, respectively. C. dubia exhibited the greatest sensitivity to the pyrethroids, with an LC50 of 0.07 μg/L for bifenthrin. C. dubia was equally or more sensitive than D. magna to all of the insecticides.
Dicofol (kelthane®)-induced eggshell thinning in captive american kestrels
Authors: Clark Donald R. , Spann James W. , Bunck Christine M.
Published: March 2010

Reproductive parameters of American kestrels (Falco sparverius) were measured through two breeding seasons. Exposure to Kelthane® (containing no DDT-related compounds) at dietary concentrations of 0 (control), 1,3, 10 and 30 μg/g (wet weight) began in late November before, and continued through, the second season. Kelthane thinned eggshells and lowered the thickness index at dietary concentrations ≥3 μg/g and it reduced shell weight at ≥10μg/g when comparisons were to concurrent controls. Kelthane reduced the thickness index at ≥3 μg/g and it reduced shell thickness and weight at ≥10 μg/g when comparisons were to the same birds during the previous season. All changes were dose-related. It was not previously known that as little as 3 μg/g dicofol could cause these effects. Kestrels resembled previously studied eastern screech-owls (Otus asio) in that 10 μg/g reduced hatchability of eggs. Both these raptors showed eggshell changes without serious effects on production of young. Available data show dicofol only equal to or less effective than DDE as a shell-thinning agent. Also, DDE may have more impact than dicofol on such critical aspects of reproduction as egg hatchability and survivability of hatchlings. Field studies of dicofol residues in food chains and of residue concentrations in eggs vs. nesting success from areas of heavy dicofol use are needed to judge this chemical's ecological impact.