bluuebunny/crossref_metadata_2025 huggingface dataset:
Interlaboratory comparison of cholinesterase assay measurements
Authors: Marden B. Thomas , Bennett Jewel K. , Fairbrother Anne
Published: March 2010

Twelve wildlife toxicology laboratories participated in an interlaboratory survey of cholinesterase (ChE) assays to determine comparability of absolute ChE values and estimates of ChE inhibition from organophosphorus insecticide-dosed birds and to examine the type and consistency of methods employed by laboratories for the measurement of ChE Supernatants of brain from northern bobwhite quail (Colinus virginianus) were prepared from untreated (UT) and methyl parathion (MP)-treated birds (5 mg/kg). Assays also were conducted on a commercial preparation of acetylcholinesterase from an electric eel. All laboratories performed the ChE assays using the colorimetric assay with temperature and read times varying by laboratory. There was substantial variation in the results of ChE analyses among participating laboratories The ChE values from untreated birds ranged from 2 6 to 28.0 μmol acetylthiocholine iodide (ACTI) hydrolyzed/min/mg tissue (mean = 14.8 sd = 7 1). For the MP-treated group, ChE activity values showed a range of 1 5 to 15 3 μmol ACTI hydrolyzed/min/mg tissue (mean = 8 1, sd = 3 9) Percent inhibition values of MP-treated compared to untreated birds ranged from 37 to 51% for reported results and 37 to 49% for corrected data (activity calculated from reported absorbance data) Laboratories were most consistent in their estimates of percent inhibition of ChE activity Differences among laboratories were partially explained by differences in the methods employed for the analysis of ChE. Assay temperature and duration appeared to affect the absolute values the most However, differences in reported ChE activity values existed even when methods were very similar These results do not support the concept of using published normal ChE values from other laboratories to assess ChE inhibition in field-collected samples
Influence of ultraviolet light on the toxicity of sediments contaminated with polycyclic aromatic hydrocarbons
Authors: Ankley Gerald T , Collyard Scott A , Monson Philip D , Kosian Patricia A
Published: March 2010

Standard 10 d toxicity tests were conducted with freshwater benthic invertebrates using sediments containing a range of concentrations of polycylic aromatic hydrocarbons (PAHs) The assays were performed both under normal laboratory fluorescent light and ultraviolet (UV) light, which mimicked wavelengths present in sunlight, at about 10% of ambient solar intensity In sediments with elevated PAH concentrations, tests conducted with UV light resulted in significantly greater mortality of Hyalella azteca (amphipods) and Lumbriculus variegatus (oligochaetes) than tests performed under otherwise comparable conditions with fluorescent light There also was increased mortality of these two species, relative to controls, when surviving organisms from the 10-d exposures to the PAH contaminated sediments were placed in clean water under UV light for 2 h These results suggest that the organisms accumulated PAHs from the test sediments, which were subsequently photoactivated by UV light to excited states more toxic than the ground state molecules The phenomenon of photoactivation has been examined for pelagic species exposed to PAHs, but not for benthic organisms exposed to sediment-associated PAHs Our results suggest that failure to consider photoactivation of PAHs by sunlight could result in sediment toxicity test methods or criteria that are underprotective of benthic organisms
Factors affecting phytoplankton species-specific differences in accumulation of 40 polychlorinated biphenyls (PCBs)
Authors: Stange Kari , Swackhamer Deborah L.
Published: March 2010

Experiments were conducted to compare the bioaccumulation of hydrophobic compounds among different phytoplankton divisions, and to evaluate the factors that affect species-specific differences. Unialgal batch cultures of Selenastrum capricornutum, Anabaena sp., and Synedra sp. were exposed to 40 PCB congeners at 11°C for 40 d. PCBs selected for this study represented all 10 homologs, different substitution patterns, and a wide range of physical-chemical properties representative of compounds known to bioaccumulate in aquatic organisms. Congener-specific partitioning into the algal phase over time was investigated. Species differences were observed in the rate and magnitude of accumulation. For all species, a rapid association of PCBs with the algal phase was followed by a slower partitioning from the media to the algae, which continued for several days. Bioaccumulation factors (BAFs) could be predicted from Kow for PCB congeners with log Kow values <6.0, whereas no such correlation was found for the more hydrophobic congeners. Normalization of BAFs to total lipid or glycolipid content reduced some of the variability between species for the less hydrophobic congeners, but not for the more hydrophobic congeners. Normalization of BAFs to the phospholipid fraction reduced species variability for the more hydrophobic congeners, supporting the hypothesis that these compounds have restricted membrane permeability.
Comparative acute toxicities of several pesticides and metals to Mysidopsis bahia and postlarval penaeus duorarum
Authors: Cripe Geraldine M.
Published: March 2010

Effects of toxic chemicals on estuarine and marine crustaceans are often evaluated using the mysid Mysidopsis bahia. In a literature survey of results of acute toxicity tests with estuarine crustaceans, Mysidae and Penaeidae were generally the two most sensitive families. However, neither family was consistently more sensitive (higher LC50 divided by lower LC50 > 2). Mysids were 54 times more sensitive to pyrethroids than were penaeids (N = 3 studies). Yet penaeids were 36 times more sensitive (N = 4 studies) to organochlorines and 5 times more sensitive (N = 17 studies) to organophosphates than were mysids.

Acute exposures of ≤24-h-old mysids and second postlarval pink shrimp Penaeus duorarum were conducted to compare responses of these crustaceans to each other, and to values from the literature for other estuarine crustaceans. The test compounds were chloride salts of cadmium, copper, and zinc; the organophosphates diazinon, fenthion, and malathion; and several pyrethroids – cypermethrin, fenvalerate, and permethrin.

Results showed that pyrethroid toxicities to mysids and postlarval pink shrimp were similar, organophosphate toxicities were within a factor of 2.6 for both species, and mysids were 3 to 26 times more sensitive to the metals than were larval pink shrimp.
Uncertainty, complexity and post-normal science
Authors: Funtowicz Silvio O. , Ravetz Jerome R.
Published: March 2010

The quality of the scientific inputs to the policy process is known to be problematic. No one can claim “truth” for his results. Nor can uncertainty be banished, but good quality can be achieved by its proper management. The interaction of systems uncertainties and decision stakes can be used to provide guidance for the choice of appropriate problem-solving strategies. When either or both of these are high, then mission-oriented applied science and client-serving professional consultancy are not adequate in themselves, and an issue-driven post-normal science is necessary. Just as in cases with ethical complexities (as in biomedical science) there must be an “extended peer community,” including all stakeholders in the dialogue, for evaluating quality of scientific information for the policy process.
A decision analytic framework for environmental analysis and simulation modeling
Authors: Reckhow Kenneth H.
Published: March 2010

A decision analytic approach is proposed for environmental planning and analysis under scientific uncertainty. This approach begins with the creation of a planning framework that consists of all relevant objectives and attributes, along with all feasible management options; this planning framework defines the inputs and outputs for subsequent work. Decision analysis may then be used to guide the subsequent work, beginning with the selection of predictive models linking management options to objectives. Once these models are identified, decision analysis may again be used, this time to identify environmental research and monitoring priorities. The approach is illustrated with an example concerning the management of eutrophication in Lake Okeechobee, Florida. Objectives, attributes, and management options were identified for the planning framework, and a simulation model was selected for a management objective concerned with the reduction in algal blooms. This model could then be used with uncertainty analysis to define specific scientific research and monitoring needs. Finally, once scientific analysis is complete, decision analysis can be used as the framework for decision making.
Risk-based environmental remediation: Decision framework and role of uncertainty
Authors: Dakins Maxine E. , Toll John E. , Small Mitchell J.
Published: March 2010

A methodology for incorporating uncertainty in model predictions into a risk-based decision for environmental remediation is illustrated, considering polychlorinated biphenyl (PCB) sediment contamination and uptake by winter flounder in New Bedford Harbor, Massachusetts. Sensitivity and uncertainty analyses are conducted for a model that predicts the sediment remediation volume required to meet a biota tissue concentration criterion. These evaluations help to identify the variables that most significantly contribute to uncertainty in the model prediction and allow for calculations of the expected value of including uncertainty (EVIU) and the expected value of perfect information (EVPI) for the remediation decision. The EVIU is the difference between the expected loss of a management decision based solely on a deterministic analysis and the expected loss of the optimal management decision that considers uncertainty. For the illustrative application to New Bedford Harbor, the expected loss avoided from performing an uncertainty analysis and using the resulting information to make the optimal management decision is approximately $20 million. The EVPI, the expected decrease in loss that can be achieved by having all uncertainty eliminated, is approximately $16 million.
Application of multivariate techniques to endpoint determination, selection and evaluation in ecological risk assessment
Authors: Landis Wayne G. , Matthews Robin A. , Matthews Geoffrey B. , Sergeant Anne
Published: March 2010

Ecological risk assessment has evolved so that the interaction among the components is now an implicit assumption. Unlike single species-based risk assessments, it is often crucial in environmental or ecological risk assessments to be able to describe a system with many interacting components. In addition, some quantifiable description of how different biological communities respond upon the addition of a toxicant or some other stressor is required to adequately describe risk at the ecosystem level. Three methods have been applied at this level: the mean strain measurement used by K. Kersting, the state-space analysis pioneered by A.R. Johnson, and the nonmetric clustering developed by G. Matthews for ecological data sets and for analysis of standardized aquatic microcosm data. Each method has direct application to the description of an affected ecosystem with-out reliance upon a single specific and perhaps misleading endpoint. Each also can assign distance or probability measures in order to compare the control to treatment groups. Nonmetric clustering (NMC) has the advantage of not attempting to combine different types of scales or metrics during the multivariate analysis and is robust against interference by random variables. Applications of these methodologies into an ecological risk assessment should have the benefit of combining large interactive data sets into distinct measures to be used as a measure of risk and as a test of the prediction of risk. The primary impact of these methods may be in the selection and interpretation of assessment and measurement endpoints. Much recent debate in toxicological studies has focused on appropriate measurement endpoints for tests. Nonmetric clustering and other multivariate techniques should aid in the selection of these endpoints in ways meaningful at the ecosystem level. We suggest that the search for assessment and measurement endpoints be left to the appropriate multivariate computation algorithms in the case of multispecies situations. Application of these methods in the verification and validation process of risk assessment will serve to check the selection of endpoints during modeling exercises and to improve the presentation of assessment criteria.
Ecological risk assessment for river sediments contaminated by creosote
Authors: Pastorok Robert A. , Sampson Jennifer R. , Jacobson Michael A. , Peek Daniel C.
Published: March 2010

An ecological risk assessment was conducted for sediments of the lower Willamette River near a wood-treatment (creosote) facility. Both surface and subsurface sediments near the facility are contaminated by polycyclic aromatic hydrocarbons (PAHs). Limited contamination of sediments by dioxins/furans, chlorinated phenols, and arsenic was also observed. Sediment bioassays based on amphipod (Hyalella azteca) mortality and Microtox® (Photobacterium phosphoreum) bioluminescence showed toxicity within approximately 300 ft of the shoreline, with a highly toxic area (i.e., possible acute lethal effects in sedentary benthic species) near a dock used for creosote off-loading. The relatively low concentrations of contaminants measured in crayfish muscle tissue and the absence of serious lesions in livers of large-scale sucker collected near the site suggest that excess risk to mobile species from chronic contamination is low. Cursory observations indicate that acute toxic effects on crayfish may be associated with creosote seeps. There is no evidence of adverse biological effects throughout most of the main channel of the river. Evaluation of sediment chemistry data for PAHs relative to available sediment-quality criteria proposed by the U.S. Environmental Protection Agency supports this conclusion.
Physiological changes and tissue metal accumulation in rainbow trout exposed to foodborne and waterborne metals
Authors: Farag Aïda M. , Boese Connie J. , Bergman Harold L. , Woodward D.F.
Published: March 2010

Sublethal physiological effects and metal residue accumulation in tissues were measured in adult and juvenile rainbow trout fed a metal-contaminated diet and/or exposed to waterborne metals for 21 d. The consumption of metal-contaminated invertebrates from the Clark Fork River, Montana, significantly affected scale loss and metal accumulation in gut tissue of adult trout. Survival, scale loss, and metal accumulation in gill and kidney tissue were affected by exposure to a waterborne mixture of Cd, Cu, and Pb at twice the acceptable levels and Zn at the maximum acceptable level established by the U.S. Environmental Protection Agency for protection of aquatic wildlife. A combination of dietary and waterborne metals also caused lipid peroxidation in the kidney of adult fish and decreased whole-body potassium of juvenile trout. In general, metal accumulation in tissues was higher in gill and kidney with waterborne exposures and was higher in stomach and pyloric caeca with dietary exposure. And metal concentrations in juvenile whole-body tissues accumulated significantly with a combination of waterborne and dietary metals. Although some physiological changes were noted (scale loss, lipid peroxidation of kidney), an exposure time longer than 21 d is probably needed to observe more extensive physiological changes. Regardless, results from this study suggest that a full assessment of metal exposure to fish populations in natural systems must include evaluation of dietary as well as waterborne metal contamination.
A mechanistic structure-activity relationship for hepatic polysubstrate monooxygenase
Authors: Hollebone B.R. , Davis D. , Michelin N. , Purdy D. , Brownlee L.J.
Published: March 2010

The polysubstrate monooxygenase (PSMO) system response to hydrophobic xenobiotics is both intensive in oxidizing power and extensive in enzyme quantity. Under in vitro pseudo-first-order rate conditions the extensive properties become irrelevant, and the intensive rate-determining step depends on chemical structure. Xenobiotics react with PSMO either as inducers (adaptation domain) or as substrates (reaction domain) to produce “intended” hydroxylation, but “accidental” oxidations may also occur. Both the induction of intensive oxidizing power in the adaptation domain and the efficiency of reaction in the reaction domain depend on the strength of the weakest CH bond in the xenobiotic, consistent with either a free radical or an ionic SE2 reaction process. Only the ionic SE2 mechanism is sensitive to the electrical charge on the carbon atom of the weakest CH bond. In this study systematic “treatment” of simple hydrocarbon structures by adjacent polarizing heteroatoms N, Cl, and O inhibited substrate metabolism in direct proportion to their polarizing power. With this evidence of preferential SE2 behaviour, a QSAR is proposed that allows prediction of four types of disease end points. These arise as combination of conditions of intended or accidental oxidations combined with release of metabolites into cytosolic or lipid media.
Chemical characterization and toxicological testing of windrow composts from explosives-contaminated sediments
Authors: Griest W.H. , Tyndall R.L. , Stewart A.J. , Caton J.E. , Vass A.A. , Ho C.-H. , Caldwell W.M.
Published: March 2010

Aerated and nonaerated windrow composts of explosives-contaminated sediments at the Umatilla Army Depot Activity (UMDA, Hermiston, OR) were characterized chemically and toxicologically as a function of composting time. The concentrations of explosives in organic solvent extracts of the composts and in the aqueous leachates of the composts, the bacterial mutagenicity of organic solvent extracts from the composts, and the toxicity of aqueous leachates from the composts to Ceriodaphnia dubia all declined rapidly (<15 d) with composting. The nonaerated windrow method of composting was slightly more efficient than was the aerated windrow method for reducing explosives concentrations in the composts (TNT, 99.9%; RDX, >99.7%; HMX, 98.5%) and in their leachates (>99.6%, >98.8%, and >97.5%, respectively). Extractable mutagenicity declined 99.7 and 97.9%, respectively, for strains TA-98 and TA-100 (without S-9 metabolic activation) in the nonaerated compost. The two types (aerated and nonaerated) of windrow composts had about the same level of efficiency in lowering leachable toxicity (by 92% and 87%, based on reductions in C. dubia survival and fecundity, respectively). Thus, windrow composting appeared to be at least as effective as static-pile and mechanically stirred composting evaluated previously. Windrow composting also appeared to be somewhat more effective for HMX transformation.
Life-cycle changes and zinc shortage in cadmium-tolerant midges, chironomus riparius (diptera), reared in the absence of cadmium
Authors: Postma Jaap F. , Mol Sandra , Larsen Hanne , Admiraal Wim
Published: March 2010

Adaptation to selected metals is known to modify life-cycle characteristics of some invertebrates and can modify the response to other metals. The reverse process, i.e., adaptation to nonpolluted conditions in a metal-tolerant strain, was studied here for a cadmium-tolerant population of the midge Chironomus riparius to detect whether this “backward” adaptation followed the same lines. It appeared that cadmium-tolerant populations, reared in the absence of cadmium, continued to suffer from high mortality rates and lowered larval growth rates and reproductive success. Also, some cadmium-tolerant populations accumulated more zinc than did nontolerant populations. Successive experiments in which both cadmium-tolerant and nontolerant populations were exposed to zinc indicated that the reduced growth rate and reproduction were a direct consequence of zinc shortage in tolerant midges reared in the absence of cadmium. Mortality among cadmium-tolerant midges was, however, not lowered by zinc exposure and, judged by their high mortality rates, these midges were even more sensitive to zinc than were nontolerant chironomids. It was concluded that cadmium-tolerant chironomid populations recovering from prolonged exposure are affected by an increased need for zinc as well as by an increased mortality rate as a direct consequence of the earlier adaptation process.
Influence of environmental factors on the physiological condition and hepatic ethoxyresorufin o-deethylase (erod) activity of gizzard shad (Dorosoma cepedianum)
Authors: Levine Steven L , Oris James T , Wissing Thomas E.
Published: March 2010

Field and laboratory experiments were conducted to monitor seasonal cytochrome P4501A monooxygenase (MO) activity (measured as ethoxyresorufin O deethylase (EROD) activity) in gizzard shad (Dorosoma cepedianum) Basal EROD activity declined in midsummer but returned to postspawning spring levels by late summer Seasonal variation in basal EROD activity corresponded with changes in liver somatic index, condition factor, and percent body lipid, indicating that seasonal variation in basal field EROD activity may result from changing physiological condition Benzo[a]pyrene induction experiments demonstrated that, although the level of EROD activity changed seasonally, the magnitude of induction relative to corn oil injected controls remained the same Kinetic studies indicated monthly changes in apparent Vmax but no change in apparent Km Taken together, these results suggest that seasonal changes in EROD activity reflect changes in hepatic P4501A protein concentration This study has demonstrated that it can be inappropriate to interpret EROD activity from a suspect site without first understanding how seasonal field conditions influence P4501A activity
Effects of embryonic exposure to methylmercury on larval prey-capture ability in the mummichog, fundulus heteroclitus
Authors: Weis Judith S. , Weis Peddrick
Published: March 2010

Embryos of the mummichog (Fundulus heteroclitus) were exposed to 2, 5, or 10 m̈g/L methylmercury (meHg) throughout development; these are concentrations below those which cause teratological effects in this species. After hatching, larvae were maintained in clean seawater and tested for prey-capture ability, using Artemia salina nauplii. Larvae that had been exposed to 10 m̈g/L methylmercury (and in two out of three trials, 5 m̈g/L) initially exhibited slower prey-capture ability than did the other groups. This is an indication of a subtle functional impairment due to the toxicant (“behavioral teratology”). However, the effect was transitory, and by about 1 week after hatching the prey capture of these larvae equalled that of the controls and the other treated groups. Growth of these larvae was also comparable to that of controls. The exposure may have caused retardation of neurological development, which was subsequently compensated for, and therefore no long-lasting effects were produced. In the field, however, embryos exposed to toxicants would probably continue to be exposed as larvae, and might not have the opportunity to recover from the deleterious effects, but rather might have them augmented.
Volatile sulfides and their toxicity in freshwater sediments
Authors: Brouwer Henry , Murphy Tom
Published: March 2010

Three forms of volatile sulfides (free hydrogen sulfide, acid-volatile sulfides [AVS] and a new form, heat-volatile sulfides [HVS]), were measured and their relationships discussed. Purging of some contaminated sediments with nitrogen at 22°C failed to remove all of the free H2S, even after 6 h. With freshly H2S-spiked uncontaminated sediment, purging of H2S was complete after 2 h; however, if the spiked sediment was allowed to stand for 53 d, H2S continued to be purged, even after 43 h. The H2S likely originates from equilibrium reactions involving reduced sulfur species in the sediment. Uncontaminated sediment spiked with H2S was found to be highly toxic using a sediment-contact bioassay employing Photobacterium phosphoreum. Addition of Fe3+, which sequesters the S2−, reduced the toxicity. Two other bioassays (ATP-TOX and Toxi-Chromotest), both involving a DMSO/methanol extract of the spiked sediment, showed greatest toxicity with spiked sediment that had been standing for 22 d. The results indicate that reduced sulfur species in sediment may be a cause of toxicity observed in contaminated anoxic sediments.
Investigating the influence of incomplete separation of sediment and water on experimental sorption coefficients of chlorinated benzenes
Authors: Schrap S. Marca , Haller Manuela , Opperhuizen Antoon
Published: March 2010

The influence of incomplete separation of water and sediment in batch sorption experiments was investigated with five chlorinated benzenes (sediment/water ratios between 0.25 and 50 g/L). Only the sorption coefficients of the most hydrophobic chemical, hexachlorobenzene, decreased with increasing sediment/water ratios. This decrease is assumed to be caused by an increasing amount of sediment that was not separated from the aqueous phase. To quantify this incomplete water/sediment separation, the unseparated sediment fraction, called the third phase, was analyzed in suspension water. For this purpose the apparent enhanced solubilities of hexachlorobenzene and two polychlorinated biphenyls were determined in the suspension water. Solubilities of these compounds were found to be considerably enhanced (up to about 8 times). In addition, turbidity, dry weight, and dissolved organic carbon (DOC) measurements were used to quantify the third phase. On the basis of these third-phase analyses, experimental sorption coefficients of hexachlorobenzene were corrected for third-phase influence, where the apparent solubility measurements were the most successful.
Swelling of peats in liquid methyl, tetramethylene and propyl sulfoxides and in liquid propyl sulfone
Authors: Lyon William G.
Published: March 2010

The interactions of methyl, tetramethylene, and propyl sulfoxides and propyl sulfone during sorption onto four dewaxed, acid-form peats have been studied by means of swelling measurements. The results for sulfoxides are displayed as heteromolecular sorption isotherms, which plot amount sorbed versus S=O group activity (molar density ratio relative to methyl sulfoxide). The present swelling data are compared to previous data for a homologous series of alcohols. Propyl sulfone apparently reacted with the peats during the sorption process, and one peat (Canadian) exhibited a dramatic 26% shrinkage in volume when exposed to this reagent for 8 weeks. Pyrolysis-GC-MS study of sulfone-doped Canadian peat found that propyl sulfide was the predominant pyrolysis product, although traces of propyl sulfoxide and sulfur dioxide were also found.
Use of estuarine water column tests for detecting toxic conditions in ambient areas of the chesapeake bay watershed
Authors: Hall Lenwood W. , Ziegenfuss Michael C. , Anderson Ronald D. , Killen William D.
Published: March 2010

Various estuarine water column toxicity tests were conducted twice in nine different ambient stations in the Chesapeake Bay watershed over a 2-year period (1991 to 1993) to determine if toxic conditions existed. The following 8-d toxicity tests were conducted: larval sheepshead minnow (Cyprinodon variegatus) survival and growth test; larval grass shrimp (Palaemonetes pugio) survival and growth test; and a copepod (Eurytemora affinis) life-cycle test. During the second year of testing, two 48-h coot clam (Mulinia lateralis) tests were conducted at each station during each testing period. In 1991, the toxicity tests were conducted twice at stations in the Potomac River at Morgantown and Dahlgren, and in the Patapsco River and the Wye River at the Manor House. All of the above tests were conducted during the fall of 1992 and spring of 1993 at two stations in the Wye River, Nanticoke River, and Middle River. Inorganic contaminants, organic contaminants, and water-quality conditions were measured concurrently during the toxicity testing of ambient water. In 1991, reduced growth of sheepshead minnow larvae was reported at both Potomac River stations during the first test. Significant mortality of either the copepod or sheepshead minnow larvae was also reported at the Wye River during both tests. Results from the 1992/93 testing generally showed minimal effects for three of the test species at all stations. Reduced normal shell development was reported for the coot clam at both Middle River stations during the fall and spring tests concurrently with concentrations of various trace metals that exceeded chronic marine water-quality criteria.
Effects of biologically treated bleached-kraft mill effluent before and after mill conversion to increased chlorine dioxide substitution: Results of an experimental streams study
Authors: Haley Richard K. , Hall Timothy J. , Bousquet Theresa M.
Published: March 2010

Large-scale outdoor experimental streams were used to determine the effects of effluent on stream biota before and after conversion of a bleached-kraft mill to increased chlorine dioxide substitution. Data for long-term (6 to 9 months) exposures at 1.5 and 5 0% v/v effluent in periods before and after conversion were compared for effluent quality, rainbow trout (Oncorhynchus mykiss) production, growth, survival, and histopathology, and periphyton and macroinvertebrate community characteristics. Data for cytochrome P4501A and ethoxyresorufin O-deethylase (EROD) biomarkers in trout were obtained in an additional 1 5-month postconversion exposure. Postconversion effluent was characterized by reduced chlorinated organic constituents and adsorbable organic halides. Rainbow trout in both the pre- and postconversion periods indicated a pattern of greater size, fewer numbers, and equal or greater production in the effluent-exposed populations compared to unexposed controls. Fish health measurements, including histopathology, hematology, and liver somatic indices, did not indicate significant negative effects, contrasting with the biomarkers, where there was a significant, positive dose-response relationship with similar effluent exposures. The lack of major differences in fish and other stream biota responses following the reductions in effluent chlorinated organic compounds raises questions about the ecological relevance of these compounds at the concentrations tested.
White sucker (Catostomus commersoni) growth and sexual maturation in pulp mill-contaminated and reference rivers
Authors: Gagnon M. M. , Bussieres D. , Dodson J. J. , Hodson P. V.
Published: March 2010

Induction of hepatic ethoxyresorufin-O-deethylase (EROD) activity and accumulation of chlorophenolic compounds typical of bleached-kraft mill effluent (BKME) in fish sampled downstream of a pulp mill on the St. Maurice River, Québec, Canada, provided evidence of chemical exposure to BKME. In comparison, fish sampled over the same distances and in similar habitats in a noncontaminated reference river, the Gatineau River, demonstrated low EROD activity and contamination levels. Accelerated growth of white suckers occurred between 2 and 10 years of age in both rivers at downstream stations relative to upstream stations, suggesting the existence of gradients of nutrient enrichment independent of BKME contamination. The impact of BKME exposure was expressed as reduced investment in reproduction, as revealed by greater length at maturity, reduced gonad size, and more variable fecundity. These effects were not obvious in simple upstream-downstream comparisons, but became evident when fish from the uncontaminated Gatineau River showed increased gonadal development and reduced age and size at maturity in response to enhanced growth rates.
Toxicity of arsenic, molybdenum and selenium combinations to Ceriodaphnia dubia
Authors: Naddy Rami B. , La Point Thomas W. , Klaine Stephen J.
Published: March 2010

Previous research done on the effects of contaminant mixtures has been evaluated primarily by using acute exposures. While this was an important initial step, characterizing the effects of chronic exposures of these mixtures is more environmentally pragmatic. This study examined the sublethal interactive effects of arsenic (As), molybdenum (Mo), and selenium (Se) on Ceriodaphnia dubia using the three-brood static renewal toxicity test. A complete factorial design experiment using four levels (zero, IC12.5, IC25, and IC50 values) of each metal was performed to investigate the binary and tertiary interactions of these metals on C. dubia survival and fecundity. Results indicate three-way interactive effects in survival and fecundity with the strongest effect exhibited by Se. Molybdenum and As in binary combinations appear to be strongly antagonistic in their effects on C. dubia, even at their respective IC50 concentrations. However, generally the addition of Se to As-Mo mixtures significantly reduced survival and reproduction. The IC50 concentrations of either Mo or Se significantly reduced fecundity in all binary and tertiary mixtures. All tertiary metal mixtures, except the combination of the IC12.5 concentrations of each metal, significantly reduced C. dubia fecundity.
Predicting chronic lethality of chemicals to fishes from acute toxicity test data: Multifactor probit analysis
Authors: Lee Gunhee , Ellersieck Mark R. , Mayer Foster L. , Krause Gary F.
Published: March 2010

New methods for predicting chronic toxicity (lethality) from acute lethality data with fishes was developed and assessed. Typically, acute toxicity tests with aquatic organisms provide lethality estimates for a series of toxicant concentrations at 24, 48, 72, and 96 h of exposure. Statistical models (multiple regression) were developed that utilize acute toxicity data to establish the relation of lethality to toxicant concentration and exposure time for predicting chronic lethality. The models provide estimates of toxicant concentrations that result in a low probability of death as a function of extended exposure times. Results from 28 data sets having lethality data for both acute and chronic exposures were used to evaluate the method. It is posited that the proposed methods are highly accurate when acute lethality data meeting stated quality requirements are available.
An ecological risk assessment method for species exposed to contaminant mixtures
Authors: Logan Dennis T. , Wilson Harold T.
Published: March 2010

The method developed here provides a quantitative, objective measure of ecological risk for natural populations exposed to mixtures of chemical contaminants. It is founded on generally accepted risk assessment concepts: use of toxic units to assess the joint toxic effects of mixtures and expression of ecological risk as a relationship between toxicological end points and estimated environmental concentrations. Toxicologicai end points may be regulatory levels with zero variance and species-dependent concentrations with estimates of variance. Risk is the probability that a linear combination of toxic units exceeds 1, which expresses the probability that a measurement end point (e.g., 50% mortality in 96 h) will occur. Computations have three variations. One addresses concentration addition, in which chemicals act independently to produce similar biological effects. For noninteractive joint action with no addition, in which the biological response to the mixture is not significantly different from the response to the most toxic component, the method reduces to an analysis of extrapolation error. For other noninteractive joint action — antagonism, partial addition, and supra-addition — a correction factor similar to Konemann's mixture toxicity index is applied. An initial validation using published data indicated that increased in situ striped bass mortality was generally associated with elevated risk estimates. The method is applicable to many organisms and toxicant mixtures.
Organic ligands reduce copper toxicity in Pseudomonas syringae
Authors: Azenha Manuel , Vasconcelos M. Teresa , Cabral João P. S.
Published: March 2010

Pseudomonas syringae cells were exposed to 100 μM copper alone, or to previously equilibrated copper sulfate-ligand solutions. Ligand concentrations were determined experimentally as those that reduced the free copper concentration to 5 μM (determined with a Cu2+-selective electrode). These values were in agreement with those calculated by computational equilibrium simulation based on published stability constants. Exposure of P. syringae cells to copper sulfate, chloride, or nitrate resulted in similar high mortality, suggesting that copper was responsible for cell death. Acetate, succinate, proline, lysine, cysteine, and EDTA significantly reduced both the amount of copper bound to the cells and cell death, indicating that not only strong chelating agents but also weak and moderate copper ligands can effectively antagonize copper toxicity. However, cysteine and EDTA were considerably more effective than acetate, succinate, proline, and lysine, indicating that copper toxicity is not simply a function of free copper concentration but depends on the nature of the ligand. The results suggested that a significant fraction of copper bound to acetate, succinate, proline, or lysine was displaced to the bacteria or, alternatively, mixed copper-ligand-cell complexes could be formed. On the contrary, none of these phenomena occurred for the copper complexes with cysteine or EDTA.
Check studies with Hyalella azteca and Chironomus tentans in support of the development of a sediment quality criterion for dieldrin
Authors: Hoke Robert A. , Kosian Patricia A. , Cotter Anne M. , van dermeiden Frances M. , Ankley Gerald T. , Phipps Gary L. , Durhan Elizabeth J.
Published: March 2010

The development of sediment quality criteria (SQCs) for nonpolar compounds using equilibrium partitioning theory (EqP) requires three critical data elements for the compound of interest: (a) a reliable, measured Kow; (b) an acceptable minimum data set for the development of the final acute and final chronic values necessary to calculate a water-quality criterion (WQC); and (c) “check” experiments with appropriate freshwater and marine benthic organisms to ensure that their responses in spiked-sediment tests are in agreement with responses predicted based on EqP. This study presents the results of dieldrin check experiments with two freshwater species: the amphipod Hyalella azteca and the chironomid Chironomus tentans. Ten-day, flowthrough, water-only dieldrin LC50 values for the amphipod and chironomid were 7.6 and 1.1 μg/L, respectively. The LC50 values for the two species based on organic carbon-normalized sediment concentrations of dieldrin were generally less variable than values based on dieldrin concentrations in sediments on a dry-weight basis. Ten-day LC50 values for H. azteca and C. tentans based on measured pore-water concentrations of dieldrin were greater than those based on EqP-predicted pore-water concentrations of dieldrin. An increase in the apparent water solubility of dieldrin as a result of binding to dissolved organic carbon appeared to account for this phenomenon. Ten-day LC50 values for H. azteca and C. tentans based on EqP-predicted pore-water concentrations of dieldrin were within a factor of 25 and 3 of their respective 10-d, water-only dieldrin LC50 values. Avoidance of the dieldrin-spiked sediments may offer a partial explanation for the concentration-response results observed with H. azteca and the greater difference observed for this species between water-only and predicted pore-water 10-d LC50 values for dieldrin. Inhibition of growth in C. tentans was also a sensitive end point with effects observed at pore-water concentrations of dieldrin as small as 5.5 μg/g organic carbon. Based on these results, it appears that EqP based upon sediment organic carbon content is an appropriate model for converting WQC for dieldrin to SQC. These results also highlight the importance of using multiple benthic test species (including at least one infaunal species), end points, and sediments in SQC sediment-spiking check studies.
Effects of a complex mixture of chemical contaminants on hepatic glutathione, L-cysteine and γ-glutamylcysteine synthetase in english sole (Pleuronectes vetulus)
Authors: Nishimoto Marc , Le Eberhart Bich-Thuy , Sanborn Herbert R. , Krone Cheryl , Varanasi Usha , Stein John E.
Published: March 2010

The effects of chemical contaminants on concentrations of hepatic glutathione (GSH), cysteine (L-Cys), and the activity of γ-glutamylcysteine synthetase (γ-GCS) were assessed in English sole (Pleuronectes vetulus) in the laboratory and in fish from the Duwamish Waterway, a contaminated urban site in Puget Sound, Washington. In the laboratory studies, fish from a nonurban (reference) site were exposed to an organic-solvent extract of sediment from the Duwamish Waterway. Hepatic GSH concentrations significantly increased at 3 d after exposure to the extract at 1,000 g sediment extracted/kg fish. At this time point, hepatic GSH showed a dose-dependent increase at dosages ranging from 300 to 1,600 g sediment extracted/kg fish, whereas fish exposed to a reference sediment extract showed no increase. Moreover, the increases in GSH in fish exposed to the contaminated sediment extract were not accompanied by changes in either L-Cys concentrations or γ-GCS activity. Similarly, fish sampled directly from the Duwamish Waterway showed increased GSH concentrations but showed no significant differences in L-Cys levels or γ-GCS activity compared to fish from a reference site. These results substantiate that hepatic GSH in fish is responsive to chemical contaminant exposure and further support its use as a biomarker in environmental monitoring studies. The findings also indicate that L-Cys availability and induction of γ-GCS were not major factors in the increase of hepatic GSH in contaminant-exposed English sole.
Comparison of PCB and trace metal bioaccumulation in the blue mussel, Mytilus edulis, and the ribbed mussel, Modiolus demissus, in new Bedford Harbor, Massachusetts
Authors: Nelson William G. , Bergen Barbara J. , Cobb Donald J.
Published: March 2010

The accumulation of PCBs and trace metals was compared at 14-d intervals between two filter-feeding bivalves, the blue mussel, Mytilus edulis, and the ribbed mussel, Modiolus demissus, after deployment in New Bedford Harbor, Massachusetts, for up to 56 d. Contaminant uptake in deployed organisms also was compared with indigenous ribbed mussels. Significant mortality (>80%) occurred in blue mussels after 28 d, when water temperatures exceeded 25°C. Therefore, tissue-residue comparisons between species are presented only up to day 28, while those between deployed and indigenous ribbed mussels continue to day 56. Results indicated that total PCB tissue residues and congener distributions were not statistically different (p > 0.05) in the two mussel species on day 28. Total PCB concentrations in both deployed mussel species reached approximately 30 μg g−1 dry weight by day 28. Additionally, total PCB concentrations and congener distributions in the deployed ribbed mussels were not statistically different from the indigenous ribbed mussels on day 28, demonstrating that steady state was attained within 28 d. With respect to metal uptake, no single accumulation pattern occurred for the eight metals quantified. After 28 d, lead, cadmium, and iron concentrations in deployed blue and ribbed mussels were statistically similar. However, nickel and zinc accumulations were significantly greater in the blue mussels, and copper, chromium, and manganese were accumulated to significantly higher concentrations in the ribbed mussels. The comparison between the ribbed mussels indicated that cadmium and lead concentrations were significantly higher in indigenous than in deployed mussels after 28 d.
Effects of simulated chlorsulfuron drift on fruit yield and quality of sweet cherries (Prunus avium L.)
Authors: Bhatti Muhammad A. , Felsot Allan S , Al-Khatib Kassim , Kadir Sorkle , Parker Robert
Published: March 2010

Field experiments were conducted at the Irrigated Agricultural Research and Extension Center, Prosser, Washington, in 1992 and 1993 to study the effects of simulated chlorsulfuron (2 chloro-N [[(4 methoxy-6 methyl 1,3,5-tnazin 2 yl)amino]-carbonyl]benzenesulfonamide) drift at different reproductive growth stages of three cherry (Prunus avium L ) cultivars, Rainier, Chinook, and Bing Branches of each cultivar were treated at side-green, full bloom, postbloom, and pit hardening growth stages with 0, 251 1 × 10 7, 83 8 × 10 7, 27 9 × 10−7, 9 3 × 10−7, and 3 1 × 10−7 M chlorsulfuron In single-exposure expetiments, Chinook was adversely affected by the lower levels of chlorsulfuron Bing was not affected by levels of chlorsulfuron below 27 9 × 10 7 M The yield and quality of fruit decreased significantly with the increase in chlorsulfuron concentrations applied at full bloom and postbloom stages Reduction in yield was correlated with the severity of injury symptoms on leaves In the multiple exposure experiments, fruit yield, fruit size, and color were significantly reduced by increasing chlorsulfuron concentration and number of exposures Average firmness of fruit increased with increases in chlorsulfuron concentration The data suggested that multiple exposures of a susceptible cherry cultivar to low levels of chlorsulfuron at full bloom and postbloom stage can reduce fruit yield and delay maturity of cherries while increasing fruit firmness
The influence of multiple sewage sludge amendments on the PCB content of an agricultural soil over time
Authors: Alcock R. E. , McGrath S. P. , Jones K. C.
Published: March 2010

The polychlorinated biphenyl (PCB) content of soils from a long-term agricultural experiment that received 25 separate sewage sludge applications from 1942 to 1961 is presented, along with data from an untreated control plot. Archived plough layer (0 to 23 cm) soil samples were collected, stored, and processed in the same manner between 1942 and 1992 (i.e., before, during, and after sludge amendments) and samples of the applied sludges were available for analysis. Soil Σ PCB concentrations (defined as the sum of the 27 congeners quantified) on the control plot increased between 1942 (63 μg Σ PCB kg−1 and 1972 (560 μg Σ PCB kg−1) as a result of atmospheric deposition inputs; they subsequently declined to 13 μg Σ PCB kg−1 in 1992. A total of ˜ 1 kg Σ PCBs/hectare was applied in sewage sludges (containing 0.14 to 4.33 mg Σ PCB kg−1) to the sludge-amended plot. Soil concentrations increased accordingly, to 640 μg Σ PCB kg−1 by 1960. However, because of the continued high atmospheric deposition inputs, concentrations on this plot also continued to increase until 1972. By 1992, the sludge-amended plot contained ca. 5 times the Σ PCB content of the control plot. By 1960, ˜81% of the predicted Σ PCB added in sludge could be accounted for; this had decrease to <50 and 21% by 1984 and 1992, respectively. Marked compound-specific differences in soil persistence were noted; generally lower chlorinated (3/4-Cl) congeners became less important contributors to the Σ PCB content of the soils over time, while 5-Cl homologues and above increased.