bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosensing the acute toxicity of metal interactions: Are they additive, synergistic, or antagonistic?
Authors: Preston Sara , Coad Nicholas , Townend John , Killham Ken , Paton Graeme I
Published: March 2010

The toxicity of Zn, Cu, and Cd, alone or in combination, was assessed using two luminescence-based microbialbiosensors from different ecological niches: Escherichia coli HB101 pUCD607 and Pseudomonas fluorescens 10586 pUCD607. Significant synergistic interactions occurred between the toxic effects of the Zn and Cu and Zn and Cd combinations and the response of E. coli (i.e., toxicities of combinations of pollutants were greater than predicted from addition of individual toxicities). Significant synergistic interactions were also observed between the toxicities of Cd and Cu combinations and the response of P. fluorescens. A longer exposure time was shown to significantly increase the sensitivity of E. coli to the metal pollutants. P. fluorescens was observed to significantly decrease in its sensitivity toward Zn and Cd with a longer exposure time. It was shown that the toxicity of combinations of metals could not be modeled on the basis that their toxic action was independent of each other. The application of different models to describe interactions between combinations of metals is discussed. The importance of considering the test species and the exposure period selected for toxicity assessment was highlighted, as was the need to further investigate the toxicity of combinations of pollutants.
Metabolism and environmental degradation of pyrethroid insecticides produce compounds with endocrine activities
Authors: Tyler Charles R , Beresford Nicola , van der Woning Melanie , Sumpter John P , Tchorpe Kcaren
Published: March 2010

Pyrethroids are semisynthetic derivatives of the chrysanthemumic acids that have been developed as insecticides, and they are in widespread use. Considerable information is available regarding the toxicity, metabolism, and environmental degradation of pyrethroids, but almost nothing is known about their interactions with hormone receptors. In this study, seven commercial pyrethroids as well as products of metabolism and environmental degradation of permethrin were tested for steroid activity (both as agonist and as antagonist) in recombinant yeasts expressing the human estrogen and human androgen receptors. Pyrethroid insecticides had steroid receptor–binding activity. Fenpropathrin and permethrin both acted as weak estrogen agonists. Allethrin, bioallethrin, and cypermethrin had antiestrogenic activity, with potencies between 1,000-fold (bioallethrin) and 10,000-fold (allethrin) less than the established antiestrogen 4-OH-tamoxifen. Six of the seven pyrethroids tested had antiandrogenic activity (the most active, bioallethrin, was 70-fold less potent than flutamide). These activities, however, are believed to result either from contaminants/degradation products in the parent compounds or from metabolism of the parent compounds into active metabolites by the yeast. Three derivatives of permethrin all interacted with sex steroid hormone receptors. Three-phenoxybenzyl alcohol had both estrogenic and antiandrogenic activity, with potencies more than 100-fold greater than that of the parent compound, permethrin. Three-phenoxybenzoic acid and the cyclopropane acid derivative both had antiestrogenic activity, with approximately 100-fold and 1,000fold lower potencies than 4-OH-tamoxifen, respectively. The data presented here highlight that an understanding of the metabolism and environmental degradation of chemicals is essential for assessing the potential of chemicals to have endocrine-modulating effects.
Transformation of trinitrotoluene to triaminotoluene by mixed cultures incubated under methanogenic conditions
Authors: Hwang Philip , Chow Teresa , Adrian Neal R
Published: March 2010

2,4,6-Trinitrotoluene (TNT) is an explosive widely used by the military. Although it is no longer manufactured in the United States, large amounts of wastewater are generated annually from load, assembly, packing, and demilitarization operations. Granular-activated carbon adsorption is the standard technology for treating wastewater containing TNT and maintaining discharges within the limits established under the National Pollutant Discharge Elimination System. Studies evaluating biological treatment of pink water with an anaerobic fluidized-bed, granular-activated carbon bioreactor have been promising, but the fate of TNT is unknown. We investigated the anaerobic transformation of TNT by biofilm microorganisms obtained from a wastewater treatment plant receiving explosive manufacturing wastewater. The TNT was transformed to a mixture of 2-amino-4,6-dinitrotolune; 4-amino-2,6-dinitrotoluene; 2,4-diamino-6-nitrotoluene; and 2,6-diamino-4-nitrotoluene before culminating in the formation of triaminoto-luene (TAT). Triaminotoluene was susceptible to further degradation under anaerobic conditions, but its fate was not determined. Methane formation was inhibited but resumed after the depletion of the diaminonitrotoluene isomers. These studies demonstrate near stoichiometric formation of TAT from TNT and the transformation of 2-amino-4,6-dinitrotoluene to 2,4-diamino-6-nitrotoluene and 2,6-diamino-4-nitrotoluene by a mixed culture incubated under methanogenic conditions. This evidence indicates TAT is also a likely end-product of TNT biodegradation in the anaerobic fluidized bed bioreactor.
Adrenocorticotrophin- and cyclic adenosine 3′,5′-monophosphate-stimulated cortisol secretion in interrenal tissue of rainbow trout exposed in vitro to DDT compounds
Authors: Benguira Sandrine , Hontela Alice
Published: March 2010

The effects of DDT compounds on the function and viability of interrenal corticosteroidogenic tissue were investigated in vitro in rainbow trout (Oncorhynchus mykiss) in a dose–response study. The o,p′-dichlorodiphenyldichloroethane (DDD) was the most potent of the tested chemicals in decreasing adrenocorticotropic hormone (ACTH)-stimulated cortisol secretion by head kidney fragments compared with controls. The dbcAMP-stimulated cortisol secretion was also impaired with doses of 50 and 100 mg/L o,p′-DDD but not 25 mg/L. Tissue viability, estimated by the release of lactate dehydrogenase (LDH), was similar to controls at 25 mg/L and was decreased significantly at 50 and 100 mg/L o,p′-DDD. These results suggest that o,p′-DDD is an adrenotoxic compound that may disrupt the 3′,5′-monophosphate (cAMP) generation step and, at higher doses, induce irreversible cytotoxic effects. The p,p′-DDT induced a significant inhibition in the secretory response to ACTH and dbcAMP only at 100 mg/L, while p,p′-DDD had no effect on the cortisol secretion. A significantly decreased viability was detected at the higher doses of p,p′-DDT and p,p′-DDD without a detectable disruption of cortisol synthesis. The steroidogenic interrenal cells may be less sensitive to the DDT compounds tested than other cell populations within the teleost head kidney.
Analysis of organochlorine compounds and extractable organic halogen in three subspecies of ringed seal from Northeast Europe
Authors: Kostamo Auli , Medvedev Nikolai , Pellinen Jukka , Hyvärinen Heikki , Kukkonen Jussi V K
Published: March 2010

Oganochlorine compounds in blubber samples of the ringed seal (Phoca hispida saimensis, P. h. ladogensis, and P. h. hispida) were analyzed in order to estimate the state of pollution in three different water areas in Northeast Europe, namely, Lake Saimaa in Finland, Lake Ladoga, and the White Sea in Russia. Geographic differences in concentrations and in relative concentrations of tri- and tetrachlorocymenes, hexachlorobenzene, α-HCH, β-HCH, -γ-HCH (Lindane), seven polychlorinated bi-phenyl (PCB) congeners, and p,p′-DDT and its metabolites in ringed seals were compared. Concentrations of chlorinated hydrocarbons varied between the water areas. The highest concentrations were found in Saimaa ringed seals, followed by Ladoga ringed seals, and the lowest concentrations were detected in ringed seals from the White Sea. Extractable organic halogen (EOX) concentrations in blubber were also analyzed. The concentrations showed a geographic trend similar to those for the individual compounds identified. In Lakes Ladoga and Saimaa, the concentrations of EOX and chlorinated hydrocarbons in the blubber were dependent on the age and sex of the seals, but no such relationship was observed in samples from the White Sea.
Incidence and impact of axial malformations in larval bullfrogs (Rana catesbeiana) developing in sites polluted by a coal-burning power plant
Authors: Hopkins William A , Congdon Justin , Ray John K
Published: March 2010

Amphibian malformations have recently received much attention from the scientific community, but few studies have provided evidence linking environmental pollution to larval amphibian malformations in the field. We document an increased incidence of axial malformations in bullfrog larvae (Rana catesbeiana) inhabiting two sites contaminated with coal combustion wastes. In the polluted sites, 18 and 37% of larvae exhibited lateral curvatures of the spine, whereas zero and 4% of larvae from two reference sites had similar malformations. Larvae from the most heavily polluted site had significantly higher tissue concentrations of potentially toxic trace elements, including As, Cd, Se, Cu, Cr, and V, compared with conspecifics from the reference sites. In addition, malformed larvae from the most contaminated site had decreased swimming speeds compared with those of normal larvae from the same site. We hypothesize that the complex mixture of contaminants produced by coal combustion is responsible for the high incidence of malformations and associated effects on swimming performance.
Ecotoxicologic change at a remediated superfund site in San Francisco, California, USA
Authors: Anderson Brian S , Hunt John W , Phillips Bryn M , Stoelting Matt , Becker Jonathon , Fairey Russell , Puckett H Max , Stephenson Mark , Tjeerdema Ronald S , Martin Michael
Published: March 2010

Lauritzen Channel is an industrial waterway adjacent to the former United Heckathorn facility in the inner Richmond Harbor area of San Francisco Bay, California, USA. Marine sediments at this Superfund site were dredged from late 1996 through early 1997 to remove the primary chemicals of concern: DDT, and dieldrin. This study assessed the Lauritzen Channel marine environment immediately before and approximately one year after the dredging of sediments. The study included chemical analysis of sediments, tissue concentrations of transplanted mussels, toxicity testing of sediment samples, and characterization of benthic community structure. Results indicated that sediment toxicity to bivalve larvae (Mytilus galloprovincialis) decreased in postre-mediation samples, but that toxicity to the amphipod Eohaustorius estuarius increased significantly. Assessment of benthos at this site suggested a transitional benthic community structure. In addition, postremediation sediments remained contaminated by a variety of organic chemical compounds, including DDT, dieldrin, chlordane, polycyclic aromatic hydrocarbons, and polychlorinated bi-phenyls. Tissue concentrations of DDT and dieldrin in mussels (M. galloprovincialis) were lower than those in preremediation samples, indicating that although sediment concentrations of organochlorine pesticides remained high, concentrations of these chemicals in the water column were reduced after dredging. This study demonstrates that the components of the site assessment were useful in determining effectiveness of the remediation activities.
Uptake of trichloroethylene by hybrid poplar trees grown hydroponically in flow-through plant growth chambers
Authors: Orchard Brady J , Doucette William J , Chard Julie K , Bugbee Bruce
Published: March 2010

Phytoremediation is being promoted as a cost-effective treatment option for shallow groundwater and soils contaminated with trichloroethylene (TCE). However, its effectiveness is difficult to assess due to contradictory reports regarding the magnitude of plant uptake and phytovolatilization. Experimental artifacts and plant stress, resulting from the use of static or low-flow plant growth laboratory systems, may account for part of the discrepancy. High exposure concentrations and short durations may also cause artifacts in laboratory studies. A dual-chamber plant growth system designed to minimize experimental artifacts was used to determine the uptake of [14C] TCE by hydroponically grown hybrid poplar as a function of plant stress (aerobic and oxygen-reduced root zone), exposure concentration (1–70 mg/L), and exposure duration (12 or 26 d). The [14C]TCE recoveries ranged from 92 to 101% in 11 dosed chambers. Trichloroethylene mass equivalent concentrations in the shoot tissue (2–168 mg/kg) were dependent on the amount of water transpired and the exposure concentration. Root-zone oxygen status did not significantly impact TCE uptake. Transpiration stream concentration factors (TSCFs) determined in these studies (0.02–0.22) were independent of exposure duration and are much lower than those previously reported and predicted. The role of TSCF and other factors in estimating the significance of plant uptake in the phytoremediation of TCE-contaminated groundwater is discussed.
Avoidance of aluminum by rainbow trout
Authors: Exley Christopher
Published: March 2010

Aluminum is the principal toxicant in fish in acid waters. The ability to avoid Al, particularly at low concentrations, would confer a considerable ecological advantage, but previous research into avoidance of Al has produced mixed results. I used a cylindrical perspex tank, 150 cm in length, to study avoidance of Al by rainbow trout fry. The fish avoided Al, and their response was dependent on pH. Avoidance that was demonstrated at pHs of 5.00, 5.50, and 5.75 was abolished at a pH of 6.00. Fry avoided very low Al concentrations, being sensitive to [Al] > 1.00 μmol L−1 at a pH of 5.00. This unequivocal demonstration of avoidance by rainbow trout fry of Al may have important implications for the ecology of indigenous fish populations in surface waters impacted by acidic deposition.
Nonylphenols in sediments and effluents associated with diverse wastewater outfalls
Authors: Hale Robert C , Smith Craig L , de Fur Paul O , Harvey Ellen , Bush Elizabeth O , La Guardia Mark J , Vadas George G
Published: March 2010

Nonylphenols (NPs) have been reported to disrupt endocrine function and sexual development in aquatic organisms at low concentrations. Environmental NP burdens are predominantly derived from degradation of nonylphenol polyethoxylate surfactants. We detected NPs in discharge-associated riverine sediments adjacent to 11 of 20 active sewage treatment plants (STPs) at concentrations up to 12,400 μg/kg. While most previous studies have focused on STPs, nonylphenols were observed in association with a variety of outfall types. The highest sediment burden, 14,100 μg/kg, was detected near a federal facility's stormwater discharge. Of 75 sediments examined from 67 sites, 45% contained NP concentrations >5 μg/kg; median concentration in these NP-positive sediments was 369 μg/kg. Other surfactant-derived alkylphenolic compounds, specifically 4-tert-octylphenol and 4-cumylphenol, were observed in two sediments at 8,220 and 70,000 μg/kg, respectively. The maximum NP concentration detected in an effluent, 6,300 μg/L, was from a shipyard oil/water separator. Nonylphenols were detected (> 1.0 μg/L) in 20% of the 59 effluents examined; 10% exceeded 10 μg/L. Sediments sampled near a STP that had ceased treatment operations 20 years prior contained 54,000 μg/kg, indicative of long-term NP residence. Results indicate that NPs may be released from diverse sources, concentrate in associated sediments, and persist therein for extended periods.
Toxicokinetics of polycyclic aromatic hydrocarbons inEisenia andrei(Oligochaeta) using spiked soil
Authors: Jager Tjalling , Sánchez Francisco A. Antón , Muijs Barry , van der Velde Els G , Posthuma Leo
Published: March 2010

The accumulation of four polycyclic aromatic hydrocarbons ([PAHs]; phenanthrene, pyrene, fluoranthene, and ben-zo[a]pyrene) was tested in the earthworm Eisenia andrei in a spiked artificial soil medium. A typical peak in the body residues was observed for all PAHs around day 7, which could not be explained from changes in the total soil concentration. It is argued that the most likely cause of this peak is a decrease in the concentration in pore water, the main bioavailable phase for earthworms. This decrease is caused by biodegradation while the low rate of mass transfer from the solid state precludes replenishment. To describe the data, bioavailability was assumed to decline exponentially in time, but the shape of the accumulation curves suggests a more abrupt change. Estimates of the uptake rate (k1) are similar for all PAHs when expressed on soil solution basis (approximately 2,000 L/kg/d); the elimination rate (k2) shows a decrease with Kow as expected, but the values tend to be slightly lower than literature data. The dynamic bioconcentration factors (k1/k2) agree well with an equilibrium partitioning between soil water and the phases inside the organism.
Contribution of trace metals in structuring in situ macroinvertebrate community composition along a salinity gradient
Authors: Peeters Edwin T.H.M. , Gardeniers Jean JP , Koelmans Albert A
Published: March 2010

Macroinvertebrates were studied along a salinity gradient in the North Sea Canal, The Netherlands, to quantify the effect of trace metals (cadmium, copper, lead, zinc) on community composition. In addition, two methods for assessing metal bioavailability (normalizing metal concentrations on organic carbon and on the smallest sediment fraction) were compared. Factor analyses showed that normalizing trace metals resulted in an improved separation of trace metals from ecological factors (depth, organic carbon, granulometry, and chloride). The variation in the macroinvertebrate data was partitioned into four sources using partial canonical correspondence analysis, with the partitions being purely ecological factors, purely trace metals, mutual ecological factors and trace metals, and unexplained. Partial canonical correspondence analysis applied to total and normalized trace metal concentrations gave similar results in terms of unexplained variances. However, normalization on organic carbon resulted in the highest percentage of variation explained by purely ecological factors and purely trace metals. Accounting for bioavailability thus improves the identification of factors affecting the in situ community structure. Ecological factors explained 45.4% and trace metals 8.6% of the variation in the macroinvertebrate community composition in the ecosystem of the North Sea Canal. These contributions were significant, and it is concluded that trace metals significantly affected the community composition in an environment with multiple stressors. Variance partitioning is recommended for incorporation in further risk assessment studies.
Challenges in forecasting the long-term impacts of multiple stressors on a mid-Atlantic region, USA
Authors: Carpenter Dean E , Lunetta Ross S
Published: March 2010

The U.S. Environmental Protection Agency, Office of Research and Development, has selected a multistate region in the mid-Atlantic as a pilot location for its regional vulnerability assessment initiative. The study included an initial problem-formulation (hazard-identification) phase conducted in consultation with local stakeholders. Nine ecological hazard (stressor) categories were selected for study based on scientific criteria and resource limitations. Initial products included one or more stressor data sets (profiles) for each hazard category, which represented an initial attempt at creating a continuous baseline database necessary for subsequent ecosystem exposure assessment. Stressor profiles were developed from the interpolation of monitoring network point data, modeling forecasts, and the processing of continuous data sets. Disparate data resolutions and temporal inconsistences among profiles will require that uncertainties for each profile be documented during multiple stressor analysis. Such uncertainties in data quality must be effectively portrayed to illustrate how they can limit profile utility during quantitative exposure analysis. Current research efforts have focused on the identification of ecosystem receptor endpoints of critical importance to maintaining ecosystem function in the mid-Atlantic. This research includes the establishment of stressor–receptor exposure period, magnitude, and duration of biological importance in an initial survey-level analysis to support the selection of stressors and receptors for exposure assessment analysis. Subsequent to this selection process, receptor data sets will be assembled at appropriate spatial and temporal resolutions commensurate with the exposure pathway processes of interest. Exposure profiles will be developed based on the cooccurrence of both stressor and receptor in both space and time required to represent a biologically significant exposure.
Using historical biological data to evaluate status and trends in the Big Darby Creek watershed (Ohio, USA)
Authors: Schubauer-Berigan Mary K , Smith Marc , Hopkins Jeff , Cormier Susan M
Published: March 2010

Assessment of watershed ecological status and trends is challenging for managers who lack randomly or consistently sampled data, or monitoring programs developed from a watershed perspective. This study investigated analytical approaches for assessment of status and trends using data collected by the Ohio Environmental Protection Agency as part of state requirements for reporting stream quality and managing discharge permits. Fish and benthic macroinvertebrate metrics collected during three time periods (1979–1981, 1986–1989, 1990–1993) were analyzed for the mainstem of Big Darby Creek, a high-quality warm-water stream in central Ohio, USA. Analysis of variance of transformed metrics showed significant differences among time periods for six fish metrics. In addition, significant positive linear trends were observed for four metrics plus the index of biotic integrity score, and negative linear trends for two fish metrics. An analysis of a subset of sites paired by location and sampled over the three periods reflected findings using all available data for the mainstem. In particular, mean estimates were very similar between the reduced and full data sets, whereas standard error estimates were much greater in the reduced subset. Analysis of serial autocorrelation patterns among the fish metrics over the three time periods suggests changes in the nature of stressors over time. A comparison within the most recent time period showed significantly better condition for Big Darby Creek mainstem than for Hellbranch Run (the easternmost subwatershed), after adjusting for watershed size. The consistency of paired and nonrandomized results suggested that either type of data might be judiciously used for this watershed assessment. Results indicated that overall biological condition of the mainstem of the Big Darby Creek watershed has significantly improved since the early 1980s.
Empirical stressor–response relationships for prospective risk analysis
Authors: Gordon Steven I , Majumder Sarada
Published: March 2010

Environmental modeling has long been a recognized part of environmental risk assessment. Traditionally, environmental models have been deterministic models for specific processes over small areas using spatially aggregated subunits for data collection and processing. For an analysis of environmental risk factors on a regional scale, such models are not always appropriate because of uncertainties in the processes, heterogeneity of the environment, and extensive data requirements. Under such circumstances, statistical modeling of the environment can offer useful insights because it deals with a combination of processes and provides a broad view of the degree and significance of the factors impacting ecological resources on a regional scale. Using data from the Eastern Cornbelt Plains ecoregion of Ohio, USA, we have developed several statistical models relating anthropogenic activities on the watershed and a set of stream condition variables to the biological quality of stream segments. The effects of land use and in-stream physical and chemical factors on the biological indicator, the index of biotic integrity, have been studied using nested watersheds as geographic units. The effects of scale and spatial aggregation have been integrated into the model. A geographic information system database was built using Arc/Info® software (Environmental Systems Research Institute, Redlands, CA, USA) for integrating and summarizing data. The results can be used as a screening model to help planners review the potential cumulative impacts of human activities on indicators of fish community structure. Future work will try to account more explicitly for distance decay of pollutants and the effects of underlying geology and soils on variations in biological diversity.
Can biological assessments discriminate among types of stress? A case study from the Eastern Corn Belt Plains ecoregion
Authors: Norton Susan B , Cormier Susan M , Smith Marc , Jones R Christian
Published: March 2010

We investigated the feasibility of using the structure of fish and benthic macroinvertebrate communities to distinguish among major types of stressors (e.g., siltation, nutrient enrichment, and stream structural degradation) using spatially and temporally matched data on stressors and responses. The 19 stressor variables addressed stream chemistry and in-stream habitat and included biological oxygen demand (BOD), total suspended solids, nitrogen, phosphorus, and components of the Qualitative Habitat Evaluation Index. The 42 response variables addressed fish and invertebrate community structure and included many of the component metrics of the Index of Biological Integrity and the Invertebrate Community Index as well as variables specifically calculated for this project. All data were collected between 1988 and 1994 by the Ohio Environmental Protection Agency in the Eastern Corn Belt Plains ecoregion. Prior to analysis, variables were transformed to near normality, and variables significantly correlated with drainage area were fit to regression models and the resulting residuals used in the analyses. Multivariate analyses included factor and discriminant analysis. The first six stressor factors explained 69% of the variation. Discriminant functions formed using the response variables significantly separated site clusters classified into high, medium, and low categories along stressor gradients. Both fish and macroinvertebrate variables were important in distinguishing site categories. For example, percentage Tanytarsini midges and percentage Glyptotendipes were important in distinguishing sites having high and low BOD. Percentage darters was associated with sites having high scores for stream corridor structure and low concentrations of inorganic nutrients, and percentage round-bodied suckers was associated with sites having low BOD and low concentrations of zinc and lead. These results indicate that diagnostic models may be developed that will be useful for site-specific and regional assessments.
Using regional exposure criteria and upstream reference data to characterize spatial and temporal exposures to chemical contaminants
Authors: Cormier Susan M , Lin Edith LC , Millward Michael R , Schubauer-Berigan Mary K , Williams Daniel E , Subramanian Bhagya , Sanders Randall , Counts Bernie , Altfater David
Published: March 2010

Analyses of biomarkers in fish were used to evaluate exposures among locations and across time. Two types of references were used for comparison, an upstream reference sample remote from known point sources and regional exposure criteria derived from a baseline of fish from reference sites throughout Ohio, USA. Liver, bile, and blood were sampled from white suckers (Catostomus commersoni) and common carp (Cyprinus carpio) collected during 1993 and 1996 in the Ottawa River near Lima, Ohio. Levels of exposure were measured for petroleum by naphthalene-type metabolites, combustion by-products by benzo[a]pyrene-type metabolites, coplanar organic compounds by ethoxyresorufin-O-deethylase (EROD) activity, and urea by blood urea nitrogen (BUN) levels. The four biomarkers analyzed proved effective in determining differences between reference and polluted sampling sites, between geographically close (<0.5 km) sites, and between sampling years at sites common in both years. Calculated exposure criteria levels of the polycyclic aromatic hydrocarbon bile metabolites were found to be a conservative approximation of levels from a designated reference site and could thereby permit comparison of biomarker levels of fish from the Ottawa River to a regional reference level. Polycyclic aromatic hydrocarbon bile metabolite and EROD activity levels were more reflective of spatial patterns of contamination than BUN, although all biomarkers indicated differences overtime. Biomarkers from white suckers seemed to be more responsive in detecting changes in contaminant levels than the same biomarkers from common carp. Lower levels in 1996 of all biomarkers at many sites suggested lower exposures than in 1993 and could be indicative of some improvement over the period.
From plan to practice: Implementing watershed-based strategies into local, state, and federal policy
Authors: Jones Alice L , Gordon Steven I
Published: March 2010

Planners are becoming increasingly interested in watershed-based plans as a way to more accurately reflect the natural landscape processes that cross the borders of political jurisdictions. Although developing plans that cross political boundaries is a relatively simple matter, establishing the transboundary authority necessary to implement such plans is often a much different matter. We investigated the regulatory mechanisms under which a watershed-based storm-water management plan could be implemented in the Big Darby Creek, Ohio, USA, a national scenic river currently facing critical threats from nonpoint sediment- and pollutant-loaded storm-water runoff in the rapidly urbanizing portions of the watershed. The watershed encompasses portions of 7 counties, 11 incorporated areas, and 26 townships, each of which has some authority over land use and storm water. The transboundary options explored include creation of a storm-water utility, creating a conservancy district, or an independent approach requiring all jurisdictions in the watershed to simultaneously adopt a series of storm-water ordinances. We evaluated these options on a number of characteristics, including their relative ability to control runoff quality and quantity, the locus of political control and enforcement authority under each, funding considerations, and the likelihood of acceptance given the region's existing political realities. Although a central authority such as a conservancy district or storm-water management district would likely be most effective in protecting water quality, the long tradition of local controls on land use makes this politically infeasible. Thus, we argue that a watershed-based protection plan for the Darby region will require the simultaneous independent approach. The case study of the Big Darby suggests that the successful implementation of watershed-based plans may be more dependent on the plan's political savvy than its technical superiority.
Proximity-based measure of land use impacts to aquatic ecosystem integrity
Authors: Wente Stephen P
Published: March 2010

A proximity-based measure of land-use impacts to aquatic ecosystem integrity based on both the relative abundance and spatial distribution of land uses within a watershed is developed and evaluated. This hydrologic proximity measure assumes that the impact of the land use at a specific position in the watershed upstream from a sample site is related to the relative volume of water that would be expected to flow through that position during a storm event. In order to evaluate the utility of this measure, the fit of several models based on land use and habitat assessment measures to biological integrity data is compared to the fit of a similar model based on hydrologic proximity measures. This hydrologic proximity model explained more of the variability in observed Hilsenhoff biotic index scores (R2 = 0.92) than land use impacts estimated as the watershed surface area occupied by each land use (R2 = 0.83), U.S. Environmental Protection Agency habitat assessment methods (R2 = 0.68), or Ohio Environmental Protection Agency habitat assessment methods (R2 = 0.68). Additionally, an algorithm based on the hydrologic proximity measure is presented for optimizing land use conversion projects to enhance biological integrity.
Vulnerability of ecosystems of the mid-Atlantic region, USA, to climate change
Authors: Lassiter Ray R , Box Elgene O , Wiegert Richard G , Johnston John M , Bergengren Jon , Suárez Luis A
Published: March 2010

Changes in the distribution of vegetation in the mid-Atlantic region of the United States were explored for two climate-change scenarios. The equilibrium vegetation ecology (EVE) model was used to project the distribution of life forms and to combine these into biomes for a doubled-CO2 scenario generated by the GENESIS earth system model. The species model, a climate-envelope model, was used to project the distribution of 200 woody plant species for a climate-change scenario with mean 2°C warming, enhanced winter warming, and no net evapotranspiration. Results from EVE suggest a considerable northward shift of both northern and southern boundaries of the biomes that occur in the mid-Atlantic region. The species model, using the climate scenario with no net evapotranspiration, more closely examines the isolated effect of temperature. This model predicts that most species will persist in their present location, with considerable expansion northward and with a small fraction of the species throughout the region experiencing dieback. Present-day ranges of several vertebrate species, considered with anticipated climatic changes, suggest that animal range changes will also occur.
Modeling, mapping, and managing critical loads for forest ecosystems using a geographic information system: Approach of Wallonia, Belgium, to the study of long-range transboundary air pollution effects on ecosystems in Europe
Authors: Eloy Sara
Published: March 2010

This critical load approach has been developed to guide policies aimed at reducing atmospheric pollutant emissions as part of the Geneva Convention on Long-Range Transboundary Air Pollution (CLRTAP). Belgium, and more precisely the Walloon region, fit into this policy. To the best of our knowledge, the critical load for an ecosystem is defined as the maximal amount of one or more pollutant deposits below which no harmful impact appears in the ecosystem. The assessment method chosen for the Walloon region and tested during its forest ecosystem surveys is based on a simple mass balance model. This model involves management of much spatial data and, therefore, requires implementation of a geographic information system. This work has allowed the Walloon region to participate in ongoing CLRTAP negotiations and has provided an important tool with which to construct regional strategies to reduce the levels of acid pollutants.
Integrating mesocosm experiments with field and laboratory studies to generate weight-of-evidence risk assessments for large rivers
Authors: Culp Joseph M , Lowell Richard B , Cash Kevin J
Published: March 2010

Regional assessments on large rivers often are complicated because these ecosystems receive multiple, interacting effluent discharges. Confounding factors, such as complicated mixing hydraulics and historical loading effects, can result in equivocal field data that lend weak inference to ecological risk assessments. Our approach to this problem develops a strategy that defines important mechanisms of pollutant effects through the combined use of laboratory and field measurements, riverside mesocosm experiments, and the incorporation of indicators at several trophic levels. We integrate these different types of information through weight-of-evidence postulates that provide logical guidelines for establishing causation in ecological risk assessment. Using this approach, retrospective risk assessments on the Fraser River, British Columbia, Canada, indicated that the major effect of present effluent discharges has been one of nutrient enrichment and stimulation of food web productivity. In fact, the Fraser River study suggests that small increases in effluent concentration in the river may produce negative ecological effects because of contaminant stresses. The combination of field experiments with this weight-of-evidence approach yielded the scientific justification for a conceptual model that describes community shifts across a nutrient–contaminant gradient. We conclude that the use of stream mesocosms with the weight-of-evidence approach is highly useful for establishing a mechanistic understanding of community responses to stressors at a regional scale. In addition, this approach will be useful when greater understanding of a particular class of anthropogenic stressors (e.g., specific types of effluent) is required to improve regulatory guidelines.
Diel temperature effects on the exchange of elemental mercury between the atmosphere and underlying waters
Authors: Loux Nicholas T
Published: March 2010

Ample scientific literature demonstrates that elemental mercury evasion from natural waters displays a diel cycle; evasion rates measured during the day are typically two to three times the values observed at night. The traditional explanation for this phenomenon is that water column elemental mercury concentrations display a diel cycle, with elemental mercury concentrations occurring at their highest values during the day. The present study tests the hypothesis that diel atmospheric temperature cycles also may play a significant role in diel mercury evasion rates. A chemical potential model is used to provide a thermodynamic framework for the development of nonisothermal Henry's law constants to describe atmospheric–aqueous partitioning of elemental mercury under temperature disequilibrium conditions. The effects of temperature disequilibrium on aqueous diffusive layer transport properties also are examined. Findings suggest that under one set of real-world temperature disequilibrium conditions, diel evasion rate variations of up to 44% can be anticipated. Given the inability to consider the effects of temperature disequilibrium on aqueous diffusive layer thicknesses, the actual effects of temperature disequilibrium on rates of mercury evasion may exceed this value. Finally, the temperature disequilibrium phenomenon may be most significant for atmospheric–aqueous exchange of trace toxicants that do not experience dynamic environmental speciation behavior.
Structure-toxicity assessment of metabolites of the aerobic bacterial transformation of substituted naphthalenes
Authors: LeBlond Jeffrey D , Applegate B ruce M. , Menn Fu-Minn , Schultz T Wayne , Sayler Gary S.
Published: March 2010

Pseudomonas fluorescens 5R, a naphthalene-degrading bacterium isolated from manufactured gas plant soil contaminated with polycyclic aromatic hydrocarbons, was examined for its degradative capacity of a number of substituted naphthalenes. In general, those compounds substituted on only one ring with an electrically neutral substituent were found to be transformed primarily to substituted salicylic acids according to the classical (NAH7) naphthalene dioxygenase-initiated upper pathway reactions of the naphthalene degradative pathway (i.e., the NAH system). Dimethylnaphthalenes with a substituent on each ring, and certain halogenated naphthalenes, were transformed via a monohydroxylation reaction to form hydroxylated dead-end products. Of the substituted salicylic acids examined, only 3- and 4-methylsalicylic acid, the respective products of the degradation of 1- and 2-methylnaphthalene, were further degraded by salicylate hydroxylase and catechol 2,3-dioxygenase, the first two enzymes of the NAH lower pathway. Using the Tetrahymena pyriformis acute toxicity assay, many of the monohydroxylated products of incomplete biodegradation were found to be polar narcotics. Substituted salicylic acids that are not further degraded by the NAH lower pathway were found to be toxic via carboxylic acid narcosis.
Interactions between soil, toxicant, and alux-marked bacterium during solid phase–contact toxicity testing
Authors: Shaw Liz J , Beaton Yvonne , Glover L Anne , Killham Kenneth , Meharg Andrew A
Published: March 2010

Bioluminescence-based, solid-contact toxicityassaysallow test bacterium and toxicant tointeract atthesolid-solution interface. A lux-marked bacterium, Burkholderia sp. RASC, and 2,4-dichlorophenol (2,4-DCP) were used to characterize these interactions. In the basic bioassay, cells were added to soil slurries containing 2,4-DCP (0–120 μg ml−1). After 15 min, soil was removed by centrifugation, and bioluminescence in the supernatant was determined. Investigation of 2,4-DCP adsorption to soil revealed that sorption was linear and not significantly (p > 0.1) affected by the presence of Burkholderia cells. The numbers of culturable Burkholderia cells in the assay supernatant were 48.2 to 64.8% of the inoculum and independent of the soil weight. The effect of soil on 2,4-DCP toxicity was investigated by comparing soil aqueous extract and contact assays. The percentage bioluminescence for the contact assay was consistently higher than the extract assay at all test concentrations, and counts of viable Burkholderia cells were enhanced by the presence of 2,4-DCP in the contact assay. Expressing results as specific bioluminescence decreased the variability in response and the discrepancy in results between the two protocols. We suggest that solid-contact assays need improvement to ensure defined contact between cells and solid phase, and that the reporting of specific activity should be emphasized.
Responses of Folsomia fimetaria (Collembola: Isotomidae) to copper under different soil copper contamination histories in relation to risk assessment
Authors: Scott-Fordsmand Janeck J , Krogh Paul Henning , Weeks Jason M
Published: March 2010

The collembolan Folsomia fimetaria L. was exposed in the laboratory to a range of elevated soil copper concentrations under two different contamination histories. These results were compared with the in situ abundance of F. fimetaria in a copper-contaminated field site. In the laboratory studies, an EC10 of 337 mg Cu/kg was observed for soil spiked with copper 1 d before the experiment. Using soil from a field site contaminated with copper more than 70 years previously, no effect was observed at concentrations as great as 2911 mg Cu/kg. Reproduction was threefold more sensitive than mortality or growth. Differences in copper sensitivity between sexes and between juvenile clutches were also indicated. The abundance of F. fimetaria showed no change with soil copper concentrations during the first year (spring sampling) of in situ observations. During the second year (autumn sampling), a reduced number per area was observed with increasing soil copper concentrations. Both the presence and abundance of other euedaphic collembolans generally exhibited distribution patterns similar to those of F. fimetaria. Thus, the contamination history and the toxicological endpoint were very important for interpreting the outcome of the standard laboratory toxicity test. Laboratory studies to some extent reflected the in situ abundance, but this depended on the contamination history and the field sampling time. Laboratory experiments using new copper-spiked soil provided the lowest effect levels.
Evaluation of the capacity for development of atrazine tolerance in periphyton from a swedish freshwater site as determined by inhibition of photosynthesis and sulfolipid synthesis
Authors: Nyström Bo , Paulsson Maria , Almgren Klara , Blank Hans
Published: March 2010

Periphyton communities were established onglassdisksks undëcontinuous exposure tatrazine (0.056–3.2 μM, or 12–700 μg/L) in a microcosm flowthrough system with water from the Göta Älv river in Southern Sweden. The effects of atrazine on chlorophyll a content, ash-free dry weight, algal species composition, and adenine and thymidine incorporation activity were determined after 4 weeks of continuous exposure. Tolerance of the algal community to atrazine was also determined by short-term inhibition of photosynthesis and sulfolipid synthesis. The no-effect concentrations for the long-term exposure as determined with the different methods were between 0.040 and 0.28 μM of atrazine. The algal community seemed to have a low potential for development of tolerance to atrazine. Tolerant algae, however, seemed to have some capacity to replace the more sensitive species at low long-term exposure (0.056–0.56 μM), which was reflected in a small but consistent increase of community tolerance. At higher concentrations, no algal species remained unaffected by atrazine, and consequently, no further increase in community tolerance was possible. On the contrary, the algal community appeared to become more sensitive.
Evaluation of planar halogenated and polycyclic aromatic hydrocarbons in estuarine sediments using ethoxyresorufin-O-deethylase induction of H4IIE cells
Authors: Gale Robert W , Long Edward R , Schwartz Ted R , Tillitt Donald E
Published: March 2010

Polycyclic aromatic hydrocarbons (PAHs) and planar halogenated hydrocarbons (PHHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were determined in fractionated sediment extracts from the Hudson-Raritan estuary and Newark Bay, New Jersey, USA, as part of a comprehensive risk assessment. Contributions of PCDDs/PCDFs, PCBs, and PAHs to the total toxic equivalents (TEQs) were measured using an H4IIE bioassay and calculated from instrumentally determined concentrations using international toxic equivalency factors. The H4IIE TEQs of whole and fractionated extracts were compared to calculated TEQs to investigate the applicability of the bioassay approach for evaluating 7-ethoxyresorufin-O-deethylease induction by PHHs and PAHs present together in complex mixtures. Although 2,3,7,8-tetrachloro-dibenzo-p-dioxin contributed from 41 to 79% of the calculated TEQs from PCDDs/PCDFs and planar PCBs in all sediments sampled, the PAH-containing fractions accounted for >80% of the total TEQs determined either instrumentally or by bioassay. Calculated TEQs from PAHs, based on reported toxic equivalency factors for only seven PAHs, were severalfold greater than the bioassay-derived TEQs of PAH-only fractions of the sediment extracts. Significant correlations were observed between bioassay and instrumentally determined toxic equivalents in the more purified fractions but not in fractions only purified by size-exclusion or argentate chromatographies alone.