bluuebunny/crossref_metadata_2025 huggingface dataset:
Concentrations, transport and biological effects of dormant spray pesticides in the San Francisco Estuary, California
Authors: Kuivila Kathryn M. , Foe Christopher G.
Published: March 2010

The transport and biological effects of dormant spray pesticides were examined in the San Francisco Estuary, California, by measuring dissolved-pesticide concentrations and estimating toxicity using bioassays at a series of sites in January and February 1993. Distinct pulses of pesticides, including diazinon, methidathion, and chlorpyrifos, were detected in the San Joaquin River in January and February and in the Sacramento River in February following rainfall. The higher pesticide loads in the Sacramento River compared with those in the San Joaquin River can be attributed to the greater amount of rainfall in the Sacramento Valley. The use patterns and water solubility of the pesticides can account for the observed temporal and spatial distributions in the two rivers. The pesticide pulses detected at Sacramento were followed through the northern embayment of San Francisco Estuary. In contrast, the pesticide distribution in the Sacramento-San Joaquin Delta changed from distinct pulses to steady increases in concentration over time. Seven-day bioassays indicated that Sacramento River water at Rio Vista was acutely toxic to Ceriodaphnia dubia (water flea) for 3 consecutive d and San Joaquin River water at Vernalis for 12 consecutive d. These water samples all had the highest diazinon concentrations. Examination of 96-h LC50 values (lethal concentration that kills 50% of test organisms in 96 H) indicates that measured diazinon concentrations could account for most but not all the observed toxicity. Other pesticides present could contribute to the toxicity.
The effect of malathion 60 on Gammarus pulex (L.) below watercress beds
Authors: Crane Mark , Delaney Paul , Watson Samantha , Parker Penny , Walker Colin
Published: March 2010

The organophosphorus insecticide Malathion 60 is used to control terrestrial arthropod pests on watercress, Rorippa nasturtium-aquaticum L. (Hayek). The use of this pesticide could damage aquatic invertebrate communities in nearby chalk streams, so an in situ experiment was undertaken with the amphipod Gammarus pulex L. to determine the extent of this risk. Caged G. pulex were placed below two selected watercress beds and their associated settling pools, and their mortality, feeding rate, and acetylcholinesterase activity measured before and after the application of Malathion 60 to the watercress crop. The differences found between prespray and postspray samples of G. pulex taken from the stations immediately below both watercress beds follow: (a) the acetylcholinesterase activity was significantly lower at both stations after spray application; (b) the mortality rate was significantly higher at one station after spray application, but not at the other; (c) there were no clear effects on feeding rates at either station. Also, there were no significant detrimental effects at either of the stations located below the settling pools. Results from this study suggest that the use of Malathion 60 on watercress beds at recommended rates presents little risk to G. pulex living in streams below watercress farms if bed effluent passes through a settling pool before release.
Minnows can acclimate to total residual chlorine
Authors: Lotts Joseph William , Stewart Arthur Jay
Published: March 2010

Observations in a chlorine-contaminated stream in eastern Tennessee revealed several species of fish in areas where total residual chlorine (TRC) concentrations were often great enough to be lethal, based on the results of other studies. We used in situ and laboratory experiments to test the hypothesis that minnows could acclimate to TRC. Acclimation was assessed by time-to-death for fish exposed to a single lethal regime of TRC. In in situ experiments, striped shiner and central stoneroller minnows collected from East Fork Poplar Creek at a TRC-contaminated site and a site farther downstream, where TRC was below detection, were caged at sites in the stream where TRC concentrations were either nil or great enough to be lethal. At the cage with high TRC, minnows collected from the “TRC-contaminated” site survived two to four times longer (15.8 h vs. 6.1 h) than the same species from the “TRC-free” site. In laboratory experiments, golden shiner minnows were exposed to TRC in a stepwise increasing concentration regime (0.04 mg/L during week 1, 0.08 mg/L during week 2, and 0.12 mg/L during week 3) before being challenge-tested with a lethal concentration of TRC. Minnows that had been previously exposed to TRC survived longer than controls in each test, and the magnitude of the mean time to death increased as the TRC concentration and duration of exposure increased (1.2-, 2.5-, and 3.9-fold increases for weeks 1, 2, and 3, respectively). Another experiment with golden shiner minnows showed that a 21-d exposure to TRC at a low concentration (0.04 mg/L) only slightly increased their tolerance to TRC. Thus, several minnow species apparently can acclimate, fairly rapidly, to TRC. This study may help explain why fish kills are less common than expected in TRC-contaminated streams.
Induction and characterization of hepatic metallothionein expression from cadmium-induced channel catfish (Ictalurus punctatus)
Authors: Zhang Y. S. , Schlenk Daniel
Published: March 2010

Two low-molecular-weight proteins of approximately 10,000 daltons (Da) were isolated from the hepatic tissue of catfish intraperitoneally injected with CdCl2 (5 mg/kg). Each protein was significantly induced following Cd treatment. Bound Cd, co-eluted from DEAE anion-exchange HPLC with rabbit hepatic metallothioneins I and II, did not possess UV absorption indicative of aromatic amino acids and corresponded to the expression of two mRNA transcripts of approximately 400 base pairs, which hybridized to a full-length cDNA probe to winter flounder metallothionein (MT). Because these data indicated that these two low molecular weight proteins were hepatic MT isoforms, induction of MT mRNA expression was studied in livers of channel catfish exposed to aqueous CdCl2 utilizing the ribonuclease protection assay. Following a 7-d exposure to 10, 50, and 100 μg/L CdCl2, expression of two MT mRNAs increased in a dose-dependent manner (MT-a, r2 = 0.95; MT-b, r2 = 0.98). Each transcript was maximally induced 48 h after exposure to 100 μg/L CdCl2 and then gradually declined to approximately 20% above controls after 96 h and maintained this level of expression for 7 d. Although MT expression is rapidly induced in channel catfish by Cd, and MT mRNA measurement is a sensitive indicator of MT induction, the use of hepatic MT of channel catfish may not be a sensitive bioindicator of short-term, low-level aqueous exposures of Cd.
Uptake and elimination of resin acids and physiological responses in rainbow trout exposed to total mill effluent from an integrated newsprint mill
Authors: Johnsen Kjell , Stuthridge Trevor R. , Mattsson Kaj , Tana Jukka , Lehtinen Karl J. , Hemming Jarl
Published: March 2010

The effects of thermomechanical pulping effluents from an integrated newsprint mill were tested on rainbow trout (Oncorhynchus mykiss). Continuous-flow exposures under laboratory conditions were conducted at three dilutions (1:200, 1:400, and 1:1,000) for 8 weeks, followed by a 4-week recovery period. Sublethal effects were assessed using physiological and biochemical parameters including liver histology, hematology, serum biochemistry, and hepatic enzyme assays. Exposure was verified by analyzing water column, fish bile, and fish tissues for resin-acid concentrations. The effluent was found to be lethally toxic to rainbow trout within 3 to 4 weeks at a dilution of 1:200. Resin-acid concentrations in bile, muscle, gill, and liver showed a clear-cut positive dose response. However, relatively few responses and changes in the physiological parameters analyzed were found when comparing exposed and reference fishes. The small differences in physiological parameters between the reference group and an exposure group (1:400) after a 4-week recovery period show that the observed responses were reversible. It is noteworthy that the difference between the lowest acutely toxic concentration and the concentration at which only slight physiological responses occurred was very narrow for this effluent.
Fate of octamethylcyclotetrasiloxane (OMCTS) in the atmosphere and in sewage treatment plants as an estimation of aquatic exposure
Authors: Mueller James A. , Di Toro Dominic M. , Maiello Joy A.
Published: March 2010

Ambient concentrations of the volatile octamethylcyclotetrasiloxane (OMCTS) in natural waters were predicted using two environmental-fate analyses: an atmospheric model and a sewage treatment plant model. The atmospheric-fate analysis utilizes a completely mixed model of the troposphere where degradation occurs by hydroxyl radical oxidation. The treatment plant analysis incorporates removal mechanisms of biodegradation, volatilization, and adsorption. The treatment train consisted of primary clarifiers followed by secondary treatment using an activated sludge process. Two estimates of influent concentration were used in the model, one based on total consumption data and the other based on measured sludge data. Because of the widely varying estimates, a sampling program was undertaken and the data were used for final effluent estimates. Measured influent OMCTS concentrations of several wastewater treatment plants indicated that less than 5% of the consumable OMCTS is received by treatment plants. From the atmospheric analysis, the predicted OMCTS concentration in the ambient water in equilibrium with the atmosphere is from 10−5 to 10−8 μg/L. Using measured influent concentrations, the sewage treatment plant analysis predicted average effluent concentrations of 0.39 to 0.66 μg/L. Both analyses predicted concentrations that were less than the lowest chronic no-observed-effect concentration (4.4 μg/L), thus providing no significant aquatic exposure.
Displaying multimedia environmental partitioning by triangular diagrams
Authors: Lee Sum Chi , Mackay Donald
Published: March 2010

It is suggested that equilateral triangular diagrams are a useful method of depicting the equilibrium partitioning of organic chemicals among the three primary environmental media of the atmosphere, the hydrosphere, and the “organosphere” (natural organic matter and biotic lipids and waxes). The technique is useful for grouping chemicals into classes according to their partitioning tendencies, for depicting the incremental effects of substituents such as alkyl groups and chlorine, and for showing how partitioning changes in response to changes in temperature.
Holding-time estimates for soils containing explosives residues: Comparison of fortification vs. field contamination
Authors: Grant Clarence L. , Jenkins Thomas F. , Myers Karen F. , McCormick Erika F.
Published: March 2010

Maximum acceptable preextraction analytical holding times (MHTs) were estimated by spiking aqueous solutions of two nitramines, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and three nitroaromatics, 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), and 2,4-dinitrotoluene (2,4-DNT), into three soils. Nitramines were stable over an 8-week test period at all storage temperatures, but nitroaromatics, which were reasonably stable when frozen, degraded rapidly at room temperature and more slowly under refrigeration. In contrast, both nitroaromatics and nitramines were quite stable under refrigeration for four field-contaminated soils. When three of these field-contaminated soils were subsequently fortified with TNT and TNB, rapid degradation under refrigeration was again observed for the added nitroaromatics. The rates of degradation were quite different in the three soils, further emphasizing the uncertainties in MHT estimates derived from fortified soils. We conclude that fortified soils can produce very different estimates of MHTs, recoveries, treatability, etc., compared to field-contaminated soils even when spiking is done in aqueous media.
The effect of 210Pb and stable lead on the induction of menta deformities in chironomus tentans larvae and on their growth and survival
Authors: Bird Glen A. , Schwartz William J. , Joseph Dana L.
Published: March 2010

To determine whether menta deformities in chironomid larvae collected from Port Hope Harbour, Ontario, were the result of exposure to ionizing radiation or to heavy metals in the sediment, Chironomus tentans larvae were exposed in the laboratory to concentrations of 210Pb and stable lead representative of contaminant levels in the harbour. Exposure to 100, 1,000, and 2,000 Bq 210Pb g−1 dry sediment had no effect on larval survival, growth, or frequency of deformities. Likewise, exposure to 0.5 and 5.0 mg lead g−1 dry sediment had no effect on the larvae, but exposure to 35.0 mg lead g−1 dry sediment (the maximum levels observed in Port Hope Harbour) resulted in 100% mortality of the larvae. These results indicate that the observed mouthpart deformities in chironomid larvae of Port Hope Harbour are not the result of radiation exposure. They also indicate that heavy metals (lead) may be having an impact on the Port Hope Harbour population. Deformities were observed in all treatments and were confined mainly to the median tooth, with cleft or forked median teeth being the most common deformity. Restriction of the deformities to the median tooth is consistent with an inherited genetic effect, and we consider them to be natural abnormalities. These natural abnormalities must be considered when using chironomid mouthpart deformities as an index of environmental degradation.
Caged mussels and semipermeable membrane devices as indicators of organic contaminant uptake in dorchester and duxbury bays, Massachusetts
Authors: Peven Carole S. , Uhler Allen D. , Querzoli Francis J.
Published: March 2010

An experiment to measure organic contaminant depuration by the blue mussel (Mytilus edulis) was carried out by transplanting mussels in stainless steel cages from a known contaminated site in Dorchester Bay, Massachusetts to a documented clean site in Duxbury Bay, Massachusetts approximately 30 nmi south of the original collection site. A parallel contaminant uptake experiment was performed in which mussels from Duxbury Bay were collected and deployed in similar cages in Dorchester Bay. The bivalves were collected from each transplant site at set intervals over a period of 95 days to monitor the rates and selectivity of depuration and uptake, respectively, of polynuclear aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and chlorinated pesticides. In a related study, semipermeable membrane devices (SPMD: polyethylene bags) containing the lipid material triolein were deployed in Dorchester Bay and collected at the same frequency as the caged mussels to evaluate their effectiveness as models for estimating bioconcentration of target organic contaminants. At the Duxbury site, results suggest that the caged mussels depurated contaminants within 68 days to levels found in native animals at the site. At the Dorchester site, bivalves concentrated the contaminants to a level similar to the native M. edulis. PCB and DDT uptake rates were found to be similar between caged mussels and SPMDs; PAH uptake by the SPMDs was initially lower than by transplanted bivalves. PCB and PAH assemblages were noticeably different between bivalves and SPMDs deployed at the same site.
Estrogenic activity of surfactants and some of their degradation products assessed using a recombinant yeast screen
Authors: Routledge Edwin J. , Sumpter John P.
Published: March 2010

An estrogen-inducible screen was developed in yeast (Saccharomyces cerevisiae) in order to assess whether surfactants and their major degradation products are estrogenic. The DNA sequence of the human estrogen receptor (hER) was integrated into the yeast genome, which also contained expression plasmids carrying estrogen-responsive sequences (ERE) controlling the expression of the reporter gene lac-Z (encoding the enzyme β-galactosidase). Thus, in the presence of estrogens, β-galactosidase is synthesized and secreted into the medium, where it causes a color change from yellow to red. This recombinant strain was used to determine whether representatives of major surfactant classes and some of their principal degradation products possess estrogenic activity. The results were compared to the effects of the main natural estrogen 17β-estradiol. None of the parent surfactants tested possessed estrogenic activity. However, one class of surfactants, the alkylphenol polyethoxylates, degrade to persistent metabolites that were weakly estrogenic. Another group of degradation products, the sulfophenyl carboxylates, which are derived from the biodegradation of linear alkylbenzene sulfonates, do not appear to possess estrogenic activity.
Predicting relative toxicity and interactions of divalent metal ions: Microtox® bioluminescence assay
Authors: Newman Michael C. , McCloskey John T.
Published: March 2010

Both relative toxicity and interactions between paired metal ions were predicted with least-squares linear regression and various ion characteristics. Microtoxr̀ 15 min EC50s (expressed as free ion) for Ca(II), Cd(II), Cu(II), Hg(II), Mg(II), Mn(II), Ni(II), Pb(II), and Zn(II) were most effectively modeled with the constant for the first hydrolysis (KH for Mn+ + H2O → MOHn-1 + H+) although other ion characteristics were also significant in regression models. The [log KH] is correlated with metal ion affinity to intermediate ligands such as many biochemical functional groups with O donor atoms. Further, ordination of metals according to ion characteristics, e.g., [log KH], facilitated prediction of paired metal interactions. Pairing metals with strong tendencies to complex with intermediate or soft ligands such as those with O or S donor atoms resulted in strong interactions.
Effects of spatial and temporal variation of acid-volatile sulfide on the bioavailability of copper and zinc in freshwater sediments
Authors: Besser John M. , Ingersoll Christopher G. , Giesty John P.
Published: March 2010

Variation in concentrations of acid-volatile sulfide (AVS) in sediments from the upper Clark Fork River of Montana, USA, was associated with differences in bioaccumulation of Cu and Zn and growth of larvae of the midge, Chironomus tentans. Growth of midge larvae was significantly greater and bioaccumulation of Cu was significantly less in surface sections (0–3 cm depth) of sediment cores, which had greater concentrations of AVS and lesser ratios of simultaneously extracted metals to AVS (SEM:AVS ratios) than in subsurface sediments (6–9 cm). Concentrations of AVS were significantly less in sediments incubated with oxic overlying water for 9 weeks than in the same sediments incubated under anoxic conditions. Bioaccumulation of Cu differed significantly between incubation treatments, corresponding to differences in concentrations of AVS and SEM:AVS ratios, although midge growth did not. Bioaccumulation of Zn did not differ significantly between depth strata of sediment cores or between incubation treatments. When results from the two sets of bioassays were combined, bioaccumulation of Cu and Zn, but not growth, was significantly correlated with SEM:AVS ratios and other estimates of bioavailable metal fractions in sediments. Growth of midge larvae was significantly correlated with bioaccumulation of Zn, but not Cu, suggesting that Zn was the greater contributor to the toxicity of these sediments. Assessments of the toxicity of metal-contaminated freshwater sediments should consider the effects of spatial and temporal variation in AVS concentrations on metal bioavailability.
Toxicity and bioaccumulation of selenium to a three-trophic level food chain
Authors: Dobbs Michael G. , Cherry Donald S. , Cairns John
Published: March 2010

Three species, Chlorella vulgaris, Brachionus calyciflorus, and Pimephales promelas, were exposed to selenate for 25 d in a three-trophic level test system. The organisms were linked in a continuous flow-through system in separate vessels, with each organism feeding on the trophic level below it. These organisms were continually exposed for 25 d to 0, 110.3, 207.7, and 396.1 μg/L total recoverable selenium (Se) from selenate in natural creek water supplemented with nutrients to sustain algal growth. In an initial algal screening test, growth rates were reduced at 81.7 and 1,053.7 μg/L, with no effect at 8.5 μg/L. In the trophic test, algal populations showed evidence of reduced growth rates at 207.7 and 386.1 μg/L, but not at 110.3 μg/L. Rotifer population standing crop (measured as dry weight) was significantly reduced at 207.7 and 396.1 μg/L by day 4, and declined to below detection by day 7 at these treatments. Fathead minnow growth was impaired after 7 d at the 207.7 and 396.1 μg/L levels, with 100% mortality by day 16. A reduction in rotifers and fish biomass was also apparent at the 110.3 μg/L level after day 20. The amount of Se in whole organisms was measured throughout the experiment. Bioconcentration factors were found to be dependent on the species, treatment level, and length of exposure period, and they ranged between 100 and 1,000.
Sorption of an alcohol ethoxylate surfactant to natural sediments
Authors: Cano Manuel L. , Dorn Philip B.
Published: March 2010

U.S. consumer and industrial use of surfactants results in down the drain disposal and release after treatment in septic fields or sewage plants. Effluent may contain limited concentrations of surfactant, which may remain in receiving waters, and this residual surfactant could become associated with bottom sediments. To assess this phenomenon, we have examined the sorption of a radiolabeled alcohol ethoxylate (C15 alcohol with an average of 9 moles of ethylene oxide per mole of alcohol) to natural sediments under sterile conditions to assure that the surfactant was not biodegraded. Control experiments comparing sterilized systems with systems including 1% formalin indicated that formalin could be included in the sediment/surfactant/water mixture to prevent surfactant biodegradation yet not interfere in the sorption process. Four sediments with 0.3–2.2% organic carbon content were used in this study to determine the effect of various sediment properties on the sorption process. Equilibrium sorption was established in 2–4 h. The equilibrium sorption isotherms were determined to be nonlinear and described by the Freundlich model, and distribution ratios (ratio of surfactant concentration on sediment to aqueous concentration) at 1 mg/L surfactant ranged from 350 to 2,100 L/kg. The amount of sorption was better correlated to the percent clay content of the sediment than to the percent organic carbon content of the sediment.
Biological effects of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in bald eagle (Haliaeetus leucocephalus) chicks
Authors: Elliott  , Hart Leslie E. , Cheng Kimberly M. , Norstrom Ross J. , Lorenzen Angela , Kennedy Sean W. , Philibert Helene , Stegeman John J. , Bellward Gail D.
Published: March 2010

During the1992 breeding season, eggs of bald eagles (Haliaeetus leucocephalus) were collected within a gradient of exposure to chlorinated hydrocarbon pollutants, particularly from pulp mill point sources, on the southern coast of British Columbia, Canada. Twenty-five eggs were placed in a laboratory incubator, of which 18 hatched; chicks were sacrificed within 24 h. Hatching success was not significantly different between eggs taken from pulp mill sites and reference sites. A hepatic cytochrome P4501A (CYP1A) cross-reactive protein was induced nearly sixfold in chicks from near a pulp mill at Powell River compared to those from a reference site (p < 0.05). Hepatic ethoxyresorufin-O-deethylase (EROD) and benzyloxyresorufin O-dealkylase (BROD) activities were also significantly elevated in chicks from nests located near pulp mills compared to reference sites (p < 0.0005 and p < 0.02, respectively). A hepatic CYP2B cross-reactive protein was threefold higher in chicks from pulp mill versus reference sites, but the difference was not significant. Residual yolk sacs of eggs collected near pulp mill sites contained greater concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) compared to reference areas. No significant differences in concentrations of polychlorinated biphenyls (PCBs), non-ortho congeners, and organochlorine pesticides occurred among sites. Regressions showed that the hepatic CYP1A cross-reactive protein and EROD and BROD activities were positively correlated with 2,3,7,8-TCDD, 2,3,7,8-TCDF, and toxic equivalents (TEQsWHO—Wrld Health Organization toxic equivalence factors) in yolk sacs. No significant concentration-related effects were found for morphological, physiological, or histological parameters, such as chick growth, edema, or density of thymic lymphocytes. Using hepatic CYP1A induction as a biomarker, a no-observed-effect-level (NOEL) of 100 ng/kg and a lowest-observed-effect-level (LOEL) of 210 ng/kg TEQsWHO on a whole egg (wet weight basis) are suggested for bald eagle chicks.
Gibbs free energies of formation of pcdds: Evaluation of estimation methods and application for predicting dehalogenation pathways
Authors: Huang Ching-Li , Harrison B. Keith , Madura Jeffry , Dolfing Jan
Published: March 2010

Gibbs free energies of formation for the ideal gas, liquid phase, and species in solution were estimated for 75 polychlorinated dibenzo-p-dioxins (PCDDs) at 298.15 K and 100,000 Pa. These values were used to calculate standard redox potentials, with H2 as the electron donor. Owing to the lack of experimental thermodynamic data for the involved chemical species, the standard-state ideal gas enthalpies of formation were evaluated by several semiempirical methods including the Modified Neglect of Diatomic Differential Overlap (MNDO), Austin Model 1 (AM1), and MNDO–Parametric Method 3 (PM3). Three different implementations of Benson's group additivity method for estimation of ideal gas enthalpies of formation were also evaluated. As a result of the evaluation, the CHETAH program based on Benson's group additive method was chosen for ideal gas enthalpy of formation calculations. Entropies, vapor pressure, and aqueous solubility were calculated by existing methods in order to complete the thermodynamic cycle. Calculated redox potentials indicate that chlorodioxins, including 2,3,7,8-tetrachlorodioxin, can serve as electron acceptors in anaerobic environments, at least from a thermodynamic perspective.
Uptake of methyl mercury by the floater mussel, Pyganodon grandis (bivalvia, unionidae), caged in a flooded wetland
Authors: Malley Diane F. , Stewart A. Robin , Hall Britt D.
Published: March 2010

A 6.7-ha wetland with a pond at the Experimental Lakes Area, northwestern Ontario, was experimentally flooded to determine causes of elevated waterborne methyl mercury (MeHg) associated with impoundment. Unionid mussels, Pyganodon grandis (formerly Anodonata grandis grandis) were caged in the experimental pond before and after flooding to determine their ability to monitor the elevated waterborne MeHg. Mussels were also caged in a reference wetland pond and in the lake from which they were collected (source lake). Background levels of MeHg in source lake mussel body parts were in the order mantle < gill or visceral remains < foot or kidney and ranged from 108 to 618 ng/g dry weight. Caging in the source lake did not alter MeHg concentration in any body part. Mussels transplanted to the ponds for 90 d showed statistically significant increases above background MeHg in the mantle and visceral remains in the preflood experimental pond (waterborne MeHg 0.09 ng/L) and in the mantle, visceral remains, foot, and kidney in the reference pond (waterborne MeHg 0.24 ng/L). The visceral remains of mussels in the reference pond contained higher levels of MeHg than did those in the preflood experimental pond. Flooding increased waterborne MeHg from 0.1 to 2.3 ng/L and resulted in an increase in MeHg and total Hg (THg) in the mantle, foot, and visceral remains of mussels in the experimental pond. Inexplicably, mussels caged in a hypoxic environment in the experimental pond lost MeHg and THg from all body parts. We concluded that not only can P. grandis monitor elevation in waterborne MeHg with flooding, but the MeHg levels in mussels also reflect small differences in background levels of natural MeHg in ponds.
A limitation of the microtox® test for toxicity measurements of nonionic surfactants
Authors: Sherrard Kim B. , Marriott Philip J. , McCormick Malcolm J. , Millington Keith
Published: March 2010

The Microtox® test was successfully used to measure EC50 values of nonionic polyethoxylate surfactants. However, toxicity measurements of real samples that contain surfactants above a particular concentration, termed the critical toxicity concentration (CTC) are not valid. These samples require dilution before the test is performed, and because the relationship between toxicity and concentration is not linear above the CTC, the EC50 cannot be extrapolated back to give the toxicity of the original concentrated sample and a true estimation of toxicity is therefore not possible. This phenomenon may be related to the minimum surface tension requirement of the bacteria or other physical properties of the surfactant such as the tendency to assemble at interfaces and surfaces and the tendency to form micelles.
A quantitative analysis of the dynamics of the sorption of hydrophobic organic chemicals to suspended sediments
Authors: Lick Wilbert , Rapaka Venkatrao
Published: March 2010

Recent long-term adsorption and desorption experiments with hexachlorobenzene and three polychlorinated biphenyl congeners have clearly demonstrated that the rates of adsorption and desorption for hydrophobic organic chemicals to natural suspended sediments can be relatively slow and therefore that the assumption of chemical equilibrium may not be valid in many realistic situations. These experiments have also led to a better understanding of the adsorption, desorption, and partitioning processes. Based on this experimental work, a theoretical model of the adsorption, desorption, and partitioning of hydrophobic organic chemicals to suspended sediments has been developed. In the present article, a description of this model is given, and results of numerical calculations using this model are compared with experimental results. In the modeling, the emphasis is on the dynamics of sorption.

The model is relatively simple, with retarded chemical diffusion within the particle/floc as the basic transport process. A complicating factor is the variations in the particle/floc size and density distributions; these distributions are dependent on local conditions and may also vary with time. In the modeling, they were chosen on the basis of measurements taken during the sorption experiments. In general, good agreement between the numerical and experimental results was obtained for all cases considered.
Homogeneous hydrolysis rate constants—Part II: Additions, corrections and halogen effects
Authors: Jeffers Peter M. , Lee Wolfe N.
Published: March 2010

Neutral and alkaline rate constants were measured for 14 halogenated hydrocarbons, and new or revised rate constants were determined for hexachloroethane, trichloroethene, and 1,2-dichloroethane. These results include the effects of F or Br substitution for Cl in halogenated methanes, ethanes, and ethenes. The brominated ethanes and ethenes are more reactive than the corresponding chlorinated compounds, due to lower activation energies and higher activation entropies. Fluorine substitution increases the activation energy for some of the ethanes and greatly decreases reactivity for most of the compounds studied. However, fluorodichloromethane is about as reactive as chloroform. Complex reactions were observed in alkaline solutions of vinyl chloride and 1,2-dichlorotrifluoroethane.
Leukoproliferative response of splenocytes from english sole (Pleuronectes vetulus) exposed to chemical contaminants
Authors: Arkoosh Mary R. , Clemons Ethan , Huffman Paul , Sanborn Herb R. , Casillas Edmundo , Stein John E.
Published: March 2010

The leukoproliferative (LP) response of splenic leukocytes from the marine benthic fish English sole (Pleuronectes vetulus) stimulated with the mitogens lipopolysaccharide (LPS), concanavalin A (Con A), and pokeweed mitogen (PWM) was examined as a biomarker of immunotoxic effects. English sole were exposed to contaminants, either by injection of an organic-solvent extract of a sediment containing polycyclic aromatic compounds (PACs) or placed for up to 5 weeks on a reference sediment containing 0.15 to 1.5% (v/v) of the PAC-contaminated sediment. English sole either injected with the contaminated extract or held on PAC-contaminated sediment had an augmented response to Con A. The LP response to LPS showed no relationship to PAC exposure in laboratory-exposed fish, while PWM showed no consistent relationship to exposure to PACs. In a field study, English sole captured from an urban area in Puget Sound, Washington, USA, contaminated with PACs and other chemical contaminants had a significantly augmented LP response to Con A and PWM in comparison to the LP response in fish from a nonurban reference site. Fish from another nonurban site also had an augmented LP response to Con A, indicating that the elevation of the Con A LP response can also result from factors other than chemical contaminant exposure. In addition, English sole from this site also had an augmented LP response to LPS, whereas fish from urban sites did not exhibit an augmented LP response to LPS. Overall, the results demonstrated that although the LP response in splenic leukocytes of English sole to Con A was linked to contaminant exposure, the LP response to Con A did not exhibit high specificity as an indicator of chemical contaminant exposure. However, the concerted use of Con A, LPS, and PWM allowed for identification of apparent chemical contaminant-induced alterations of the LP response in English sole from an urban area of Puget Sound.
The potential of an earthworm avoidance test for evaluation of hazardous waste sites
Authors: Yeardley Roger B. , Gast Laura C. , Lazorchak James M.
Published: March 2010

An earthworm avoidance test has potential advantages for use in evaluation of hazardous wastes sites. Because organisms often exhibit behavioral responses at lower levels of stress than those that acute toxicity tests are able to detect, avoidance tests could provide increased sensitivity to hazardous chemicals. Avoidance is an ecologically relevant endpoint that neither acute nor sublethal tests measure. Avoidance can potentially indicate sublethal stress in a short period of time, testing is easily done in a soil matrix, and an avoidance test has the potential for specialized applications for soil testing. “Dual-control” test data established that, in absence of a toxicant, worms did not congregate, but instead distributed themselves fairly randomly with respect to the two sides of the test chambers, that is, they did not display behavior that might be mistaken for avoidance. In tests with artificial soil spiked with reference toxicants and hazardous site soils, worms avoided soils containing various toxic chemicals. Avoidance behavior proved in most cases be a more sensitive indicator of chemical contamination than acute tests. Determination of avoidance was possible in 1 to 2 d, much less than the current duration of acute and sublethal earthworm tests.
The translocation of white phosphorus from hen (Gallus domesticus) to egg
Authors: Nam Sae-Im , Macmillan Denise L. , Roebuck Bill D.
Published: March 2010

Thousands of waterfowl deaths occurring at Eagle River Flats (ERF), Anchorage, Alaska, USA, have been attributed to the ingestion of white phosphorus (P4) particles. White phosphorus has been found in the egg of one herring gull (Larus argentatus) and in the yolks of some shorebirds at ERF. The presence of P4 in eggs suggests potential toxic consequences for avian reproduction. This study was undertaken to determine the magnitude and potential importance of P4 translocation from the hen to the egg. Egg-laying hens (Gallus domesticus) were gavaged with a single dose of 1, 3, or 5 mg P4/kg body weight or dosed with 1 mg P4/kg body weight for 5 consecutive d. Eggs of dosed hens were collected daily. White phosphorus was extracted from the yolk and the white, individually, with isooctane and analyzed by gas chromatography. White phosphorus had no significant effect on chicken weight, egg weight, or shell thickness. However, laying frequency was significantly reduced (p < 0.05) in chickens receiving 1 mg P4/kg body weight for 5 d. For all treatments, P4 was detected in the yolk and not in the white. It was first detected in the yolk approx. 1 to 2 d after P4 exposure and became nondetectable 6 to 10 d after P4 exposure. The total P4 recovered from eggs of chickens treated with P4 was less than 0.01% of the administered dose.
A resource conservative procedure for comparison of dose-response relationships
Authors: Link William A. , Hill Elwood F. , Hines James E. , Henry Paula F. P.
Published: March 2010

The evaluation of effects of toxicants on a wildlife community can be complicated by varying responses among the community's constituent populations. Even within populations, considerable variability in dose-response relations may result from different avenues of exposure to the toxicant. Full-scale investigations of the dose-response relations among a variety of species and avenues of exposure can therefore be prohibitively expensive, whether this expense is measured by the number of experimental animals needed, by the human resources committed to the study, or by laboratory expenses. We propose an abbreviated protocol for investigations of multiple dose-response relations that is designed to limit these expenses. The protocol begins with the judicious choice of a baseline dose-response relation to be estimated by a full-scale study involving a minimum of five doses levels, with 10 subjects per dose level. This relation is then used as the basis for rapid screening of subsequent dose-response relations, which are compared to the baseline relation by testing for differences in the median effective dosages. These secondary studies can consist of as few as 14 animals exposed to the estimated median lethal concentration from the baseline study. We describe MS-DOS-compatible software available from the authors that can be used to analyze these data.
Persistent synthetic chlorinated hydrocarbons in albatross tissue samples from midway atoll
Authors: Jones Paul D. , Hannah Donald J. , Buckland Simon J. , Day Peter J. , Leathem Scott V. , Porter Lawrence J. , Auman Heidi J. , Sanderson J. Thomas , Giesy John P. , Summer Cheryl , Ludwig James P. , Colborn Theo L.
Published: March 2010

Anthropogenic organic contaminants have been found in even the most remote locations. To assess the global distribution and possible effects of such contaminants, we examined the tissues of two species of albatross collected from Midway Atoll in the central North Pacific Ocean. These birds have an extensive feeding range covering much of the subtropical and northern Pacific Ocean. Anthropogenic contaminants were found at relatively great concentrations in these birds. The sum of 19 polychlorinated biphenyl (PCB) congeners ranged from 177 ng/g wet weight in eggs to 2,750 ng/g wet weight in adult fat. Total toxic equivalents (TEQs) derived from polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) ranged from 17.2 to 297 pg/g wet weight in the same tissues, while the inclusion of TEQs from PCBs increased these values to 48.4 and 769 pg/g wet weight, respectively. While contaminant concentrations varied between species and tissues, the contaminant profile was relatively uniform. The profile of contaminants detected was unusual in that much of the TEQs was contributed by two pentachlorinated congeners (2,3,4,7,8-pentachlorinated dibenzofuran and 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin), and the profiles of PCB congeners did not match known sources. When compared to other studies the concentrations detected in the Midway Atoll samples were near or above the thresholds known to cause adverse effects in other fish-eating bird species.
Bioavailability of hydrophobic organic compounds from nonaqueous-phase liquids: The biodegradation of naphthalene from coal tar
Authors: Ghoshal Subhasis , Luthy Richard G.
Published: March 2010

The literature on microbial degradation of polycyclic aromatic hydrocarbon (PAH) compounds in soils and sediments shows that microbial biotreatment rates are highly variable. Although it is believed that these disparate results are somehow attributable to the bioavailability of PAH compounds, current understanding does not allow prediction of this phenomenon. This work evaluated relationships between coal tar composition and aqueous naphthalene concentration and between the rate of naphthalene mass transfer and microbial mineralization of naphthalene. The use of a dissolution-degradation framework for identifying rate-controlling phenomena in slurry biotreatment of coal tar is discussed. Experiments were performed in slurry systems with two coal tars for which naphthalene was the principal component. In slurry systems coal tar was present either as a single 0.7-ml globule or as coated onto 250-μm-diameter microporous silica beads. Independent tests were conducted with these systems to assess the rates of naphthalene mass transfer and rates of naphthalene biomineralization. The area-dependent mass transfer coefficient of naphthalene in the coal tar-silica beads system was three orders of magnitude greater than for the single coal tar globule. A coupled, solute-mass transfer biodegradation model was used to compare initial biomineralization rates with rates of naphthalene dissolution. Analysis of the results showed that the rate of biomineralization of naphthalene in the systems containing single coal tar globules was influenced by the rate of mass transfer of naphthalene.
Evaluation of the goulden large-sample extractor for acidic compounds in natural waters
Authors: Headley John V. , Dickson Leslie C. , Swyngedouw Chris , Crosley Bob , Whitley Gerry
Published: March 2010

The Goulden Large-Sample Extractor has received extensive use for monitoring and surveillance surveys of natural waters impacted by pulp and paper mills and agricultural runoff water. However, there are concerns about whether this sampler, which was originally developed for extractions of hydrophobic polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and other organochlorines, is suitable for sampling polar acidic compounds. The sampler was evaluated for recovery of surrogates for resin acids, fatty acids, herbicide acids, and chlorophenols from natural waters. Performance tests conducted in this work indicated that three surrogate compounds with Kp (CDCM/CWater pH2) values from 16,700 to 1,260 were extracted from pH 2-adjusted 20-L water samples with an average recovery of 83.6%. The surrogate compounds with Kp values less than 1,000 were extracted with significantly lower recoveries. The variability ranged from 10 to 36% relative standard deviation. Recoveries and variability compared favorably with reported recoveries and variabilities for neutral pesticide surrogates. Specific performance criteria (percent recoveries ± standard deviation, number of determinations in parentheses) observed for the surrogates 2,4,6-tribromophenol, heptadecanoic acid, O-methylpodocarpic acid, dichlorophenylacetic acid, and 4-bromophenol were 89.5 ± 24.0 (17), 82.8 ± 21.7 (18), 78.4 ± 14.8 (18), 41.9 ± 8.5 (16), and 22.1 ± 8.1 (19), respectively. Low recoveries of the 4-bromophenol surrogate may be due in part to side reactions with diazomethane. As a result, 4-bromophenol is not recommended as a surrogate. These values can be used to provide guidelines for acceptable surrogate recoveries and validation of extractions of polar acidic compounds.
Growth responses of periphyton and chironomids exposed to biologically treated bleached-kraft pulp mill effluent
Authors: Dubé Monique G. , Culp Joseph M.
Published: March 2010

Experiments were conducted in artificial streams to determine the effects of increasing concentrations of bleached-kraft pulp mill effluent (BKME) on periphyton and chironomid (Chironomidae) growth in the Thompson River, British Columbia, Canada. Periphyton growth, as determined by increases in chlorophyll a, was significantly stimulated at all effluent concentrations tested (0.25, 0.5, 1.0, 5.0, and 10.0%). Chironomid growth (total biomass and individual weight) was also significantly stimulated at low effluent concentrations (≤1.0%). At higher concentrations (5.0 and 10.0%), chironomid growth was inhibited relative to the 1.0% treatment streams but was greater than in the controls. Increases in growth were attributed to the effects of nutrient and organic enrichment from BKME. The effluent contained high concentrations of phosphorus and appears to be an important source of carbon for benthic insects grazing on the biofilm. In high-concentration effluent streams, chironomid growth decreased despite low levels of typical pulp mill contaminants (chlorinated phenolics, resin acids, and adsorbable organic halide). This suggests that other compounds in the effluent, such as wood extractives, may be inhibiting chironomid growth. These results support findings of field monitoring studies conducted in the Thompson River, in which changes in periphyton and chironomid abundance occurred downstream of a bleached-kraft pulp mill.
Predicting the toxicity of metal-contaminated field sediments using interstitial concentration of metals and acid-volatile sulfide normalizations
Authors: Hansen D.J. , Berry W.J. , Boothman W.S. , Pesch C.E. , Mahony J.D. , Di Toro D.M. , Robson D.L. , Ankley G.T. , Ma D. , Yan Q.
Published: March 2010

We investigated the utility of interstitial water concentrations of metals and simultaneously extracted metal/acid-volatile sulfide (SEM/AVS) ratios to explain the biological availability of sediment-associated divalent metals to benthic organisms exposed in the laboratory to sediments from five saltwater and four freshwater locations in the United States, Canada, and China. The amphipod Ampelisca abdita or the polychaete Neanthes arenaceodentata were exposed to 70 sediments from the five saltwater locations, and the amphipod Hyalella azteca or the oligochaete Lumbriculus variegatus were exposed to 55 sediments from four freshwater locations in 10-d lethality tests. Sediment toxicity was not related to dry weight metals concentrations. Almost complete absence of toxicity in spiked sediments and field sediments where metals were the only known source of contamination and where interstitial water toxic units (IWTUs) were <0.5 indicates that toxicity associated with sediments having SEM/AVS ratios <1.0 from two saltwater locations in industrial harbors was not metals-related as these sediments contained <0.5 IWTU. Metals-associated toxicity was absent in 100% of sediments from the remaining three saltwater field locations, where metals were the only known source of contamination and SEM/AVS ratios were ≤1.0. Two-thirds of 45 sediments from seven saltwater and freshwater field locations having both IWTUs >0.5 and SEM/AVS ratios <1.0 were toxic. Toxicity was observed less often when SEM/AVS ratios >1.0 (39%) or IWTUs >0.5 (55%) were used alone. The difference between the molar concentrations of SEM and AVS (SEM – AVS) can provide important insight into the extent of additional available binding capacity, the magnitude by which AVS binding has been exceeded, and, when organism response is considered, the potential magnitude of importance of other metal binding phases. For these reasons, SEM – AVS should be used instead of SEM/AVS ratios as a measure of metals availability. Over all published experiments with both metal-spiked and field sediments, SEM – AVS and IWTUs accurately (99.2%) identified absence of sediment toxicity and with less accuracy (79.1%) identified the presence of toxicity.