bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of environmental effects of the use of stabilized dredged material from New York/New Jersey Harbor, USA, for construction of roadway embankments
Authors: Douglas W. Scott , Maher Ali , Jafari Farhad
Published: March 2010

Since the 1997 local ban on ocean dumping of dredged sediments, the state of New Jersey has pursued a policy of environmentally sound solutions to the controversial problem of dredged material management, including beneficial use of dredged material stabilized with pozzolanic additives (SDM). A pilot study was initiated in 1998 to evaluate the use of SDM in the construction of highway embankments. Using 80,000 cubic yards of silty dredged material, 2 embankments were constructed from SDM on a commercial development area adjacent to the New York/New Jersey Harbor. This article presents the evaluation of the environmental effects of the SDM, including fugitive air emissions, leachate, and stormwater quality. Engineering properties, handling and management techniques of the SDM, constructability, and performance were also evaluated, the results of which are published elsewhere. The findings demonstrate that although there are measurable releases of contaminants to the environment from the SDM, these releases are not significant long-term threats to human health or the environment. Policies currently in place to regulate the management of SDM that include limiting placement options to previously contaminated sites with institutional and engineering controls will further reduce the potential for environmental impact and, in fact, have the potential to produce significant environmental benefit.
Impacts of gold mining and land use alterations on the water quality of central Mongolian rivers
Authors: Stubblefield Andrew , Chandra Sudeep , Eagan Sean , Tuvshinjargal Dampil , Davaadorzh Gantimur , Gilroy David , Sampson Jennifer , Thorne Jim , Allen Brant , Hogan Zeb
Published: March 2010

Conservation of water quality is inherently tied to watershed management. Efforts to protect Lake Baikal have increasingly focused on the Selenge River, a major tributary, with more than half its watershed area in Mongolia. Placer gold mining in Mongolia has the potential to load total suspended sediment (TSS), and total phosphorus (TP) into Lake Baikal and destroy spawning areas for the endangered Taimen salmon (Hucho taimen taimen). This work describes water quality assessments performed from 2001 to 2003 on Mongolian tributaries to the Selenge River. Of 7 rivers sampled, rivers with proximal mining had the worst water quality. Elevated loading of TSS and TP was observed below mining regions on the Tuul River. Flooding could breach thin strips of land separating dredge pits from river channels, resulting in massive sediment loading. Extensive disturbance of the river terrace was apparent for many square kilometers. In the mountainous headwaters of the Yeroo River, tributary drainages undergoing mining had TP concentrations 8 to 15 times higher than the main stem. TSS was 7 to 12 times higher, and turbidity was 8 times higher. Alternative mining technologies exist that could minimize impact and improve the possibility for reclamation.
Individuals versus organisms versus populations in the definition of ecological assessment endpoints
Authors: Suter Glenn W. , Norton Susan B. , Fairbrother Anne
Published: March 2010

Discussions and applications of the policies and practices of the U.S. Environmental Protection Agency (USEPA) in ecological risk assessment will benefit from continued clarification of the concepts of assessment endpoints and of levels of biological organization. First, assessment endpoint entities and attributes can be defined at different levels of organization. Hence, an organism-level attribute, such as growth or survival, can be applied collectively to a population-level entity such as the brook trout in a stream. Second, assessment endpoints for ecological risk assessment are often mistakenly described as “individual level,” which leads to the idea that such assessments are intended to protect individuals. Finally, populations play a more important role in risk assessments than is generally recognized. Organism-level attributes are used primarily for population-level assessments. In addition, the USEPA and other agencies already are basing management decisions on population or community entities and attributes such as production of fisheries, abundance of migratory bird populations, and aquatic community composition.
Incorporating sediment stability within the management of contaminated sediment sites: A synthesis approach
Authors: Bohlen W Frank , Erickson Michael J
Published: March 2010

At the Third International Conference on Remediation of Contaminated Sediments, a panel discussion was held to consider how best to incorporate sediment stability assessment (SSA) results when managing risks at contaminated sediment sites. This remains a challenge to the scientific and regulatory community, especially at sites where large volumes of legacy sediment are present below layers of recent sediment of better quality, and where in-place management may be viable. Use of a suite of empirical and predictive approaches collectively to assess potential risks resulting from bed erosion has emerged as the state-of-the-art approach for SSA, yet current practice lacks consistent guidance for conducting such assessments and for dealing with and communicating implications of uncertainty. The regulatory community lacks a decision-making framework that specifically incorporates SSA results, though it is a consideration in US Environmental Protection Agency (USEPA 2002) Principles for Sediment Management. Practitioners have not consistently communicated SSA results from a risk perspective to the stakeholder community. We believe this combination of factors, especially the inconsistent framing of results in a risk context, has contributed to discounted use of sediment stability information in decision making, fostering application of the precautionary principle, where removal is viewed as a presumed conservative but more expensive approach over in-place management options. We assert that the incorporation of SSA in decision making will be improved through the use of a consistent SSA assessment framework built around the conceptual site model, incorporating multiple lines of evidence detailing the potential impacts of large, low-probability events (e.g., the 100-y storm) on exposure and risk, and the associated uncertainties. Further advocacy of this approach was realized through panel-audience discussion at the conference. The technical methods discussed are not new; rather, it is the synthesis approach emphasized here, which by providing a framework for the systematic evaluation of how SSA is best addressed from site to site, makes the results of SSA efforts more accessible and acceptable to stakeholders and decision makers.
Uncertainties in sediment erodibility estimates due to a lack of standards for experimental protocols and data interpretation
Authors: Sanford Lawrence P
Published: March 2010

Quantitative prediction of the erodibility of muds and mud-sand mixtures is, at present, seldom possible without resorting to direct measurements, preferably in situ. A variety of devices and protocols have been developed for erosion testing, but a considerable degree of uncertainty remains with regard to the accuracy and comparability of the resulting data. This paper argues that differences in experimental protocols and data analysis procedures are a major contributing factor to uncertainty in estimates of sediment erodibility. In particular, the likelihood of a time-dependent erosion rate response under typical erosion testing conditions means that the time history of applied forcing and the chosen protocols for analyzing and interpreting data directly affect derived erosion parameters. Several straightforward ways to address this problem are suggested, including standardization of experimental design and data analysis protocols, explicit recognition and adoption of appropriate erosion model(s), and allowing for potential time/depth changes in erodibility. Experimentalists should also archive and share erosion-test time series, not just derived parameters, so that data sets may be reanalyzed within a different framework if necessary. An example is presented from an intercomparison experiment between the Virginia Institute of Marine Sciences Sea Carousel and the University of Maryland Center for Environmental Science Microcosm System, carried out in the upper Chesapeake Bay (Maryland, USA) in May 2002. Derived parameters appear to be incompatible when the data are analyzed using different procedures, but real similarities and differences are readily apparent when the data are analyzed using the same procedures.
Uncertainty in experimental techniques for measuring sediment erodability
Authors: Jepsen Richard A
Published: March 2010

There are many experimental methods currently utilized to measure sediment erodability and stability. When utilizing any of the available methods or devices to characterize erodability, one must understand the inherent uncertainty associated with each technique in relation to the application or expected measurement need. In addition, while some uncertainties are unique to a particular measurement device or technique, other uncertainties arise from variation in sediment conditions or properties. Several widely used devices and techniques are discussed with respect to their uncertainties and applicability for certain measurements. Finally, suggestions will be made on how to reduce uncertainty and manage it in model development.
Using mathematical models to assess sediment stability
Authors: Ziegler C Kirk
Published: March 2010

The application of mathematical models to a sediment stability study is presented, with an emphasis on using models as a component of an effort to develop, refine, and potentially validate a conceptual site model (CSM) for sediment transport at a study site. The utility of mathematical models is discussed, in which the modeling framework consists of linked hydrodynamic, sediment transport, and contaminant fate and transport models. Benefits and drawbacks of empirically based mechanistic models are presented. An approach for integrating modeling analyses into the development, refinement and validation of a CSM is provided. This approach focuses on a phased study that combines modeling and data-based analyses to test hypotheses related to the CSM and sediment stability. Uncertainty in modeling results is a primary concern in sediment stability studies, and issues related to model uncertainty are discussed. Finally, communication of modeling results to stakeholders is addressed.
Importance of implementation and residual risk analyses in sediment remediation
Authors: Wenning Richard J , Sorensen Mary , Magar Victor S
Published: March 2010

Management strategies for addressing contaminated sediments can include a wide range of actions, ranging from no action, to the use of engineering controls, to the use of more aggressive, intrusive activities related to removing, containing, or treating sediments because of environmental or navigation considerations. Risk assessment provides a useful foundation for understanding the environmental benefits, residual hazards, and engineering limitations of different remedy alternatives and for identifying or ranking management options. This article, part of a series of panel discussion papers on sediment remediation presented at the Third International Conference on Remediation of Contaminated Sediments held 20–25 January 2005 in New Orleans, Louisiana, USA, reviews 2 types of risk that deserve careful consideration when evaluating remedy alternatives. The evaluation of remedy implementation risks addresses predominantly short-term engineering issues, such as worker and community health and safety, equipment failures, and accident rates. The evaluation of residual risks addresses predominantly longer-term biological and environmental issues, such as ecological recovery, bioaccumulation, and relative changes in exposure and effects to humans, aquatic biota, and wildlife. Understanding the important pathways for contaminant exposure, the human and wildlife populations potentially at risk, and the possible hazards associated with the implementation of different engineering options will contribute to informed decision making with regard to short- and long-term effectiveness, implementability, and potential environmental hazards.
European environmental management: Moving to an ecosystem approach
Authors: Apitz Sabine E , Elliott Michael , Fountain Michelle , Galloway Tamara S
Published: March 2010

The European Union has adopted several environmental directives, strategies, recommendations, and agreements that require a shift from local- or regional-based regulations to more ecosystem-based, holistic environmental management. Over the next decade, environmental management in Europe is likely to focus more on biological and ecological conditions rather than physical and chemical conditions, with ecosystem health at the center of regulation and management decision making. Successful implementation of this new ecosystem management and strategic assessment process in Europe will require the integration of regulatory and technical information and extensive collaboration from among European Union member countries, between agencies, and across disciplines to an unprecedented degree. It will also require extensive efforts to adapt current systems of environmental assessment and management to the basin and ecosystem level, across media and habitats, and considering a much broader set of impacts on ecosystem status than is currently addressed in most risk assessments. This will require the understanding, integration, and communication of economic, ecological, hydrological, and other processes across many spatial and temporal scales. This article discusses these challenges and describes some of the research initiatives that will help achieve integrated ecosystem management in Europe.
Population-scale assessment endpoints in ecological risk assessment part 1: Reflections of stakeholder values
Authors: Landis Wayne G
Published: March 2010

The selection of appropriate assessment endpoints is a basic element of an ecological risk assessment, especially at regional or watershed scales. Because ecological services often are tied to specific species, the risk to populations is a critical endpoint and feature of ecological risk assessments. The first item is a discussion of the replacement of population-level risk assessment with the construct of a population-scale assessment endpoint. Next, the criteria that are currently used for assessment endpoints are reviewed and evaluated for utility in an ecological risk assessment. Following this examination, assessment endpoints from a number of regional-scale ecological risk assessments are compared. The outcome of this evaluation is that population-scale assessment endpoints are important expressions of the valued components of ecological structures. Finally, a few recommendations for the selection of assessment endpoints at a population scale are listed.
From optimization to adaptation: Shifting paradigms in environmental management and their application to remedial decisions
Authors: Linkov Igor , Satterstrom F Kyle , Kiker Gregory A , Bridges Todd S , Benjamin Sally L , Belluck David A
Published: March 2010

Current uncertainties in our understanding of ecosystems require shifting from optimization-based management to an adaptive management paradigm. Risk managers routinely make suboptimal decisions because they are forced to predict environmental response to different management policies in the face of complex environmental challenges, changing environmental conditions, and even changing social priorities. Rather than force risk managers to make single suboptimal management choices, adaptive management explicitly acknowledges the uncertainties at the time of the decision, providing mechanisms to design and institute a set of more flexible alternatives that can be monitored to gain information and reduce the uncertainties associated with future management decisions. Although adaptive management concepts were introduced more than 20 y ago, their implementation has often been limited or piecemeal, especially in remedial decision making. We believe that viable tools exist for using adaptive management more fully. In this commentary, we propose that an adaptive management approach combined with multicriteria decision analysis techniques would result in a more efficient management decision-making process as well as more effective environmental management strategies. A preliminary framework combining the 2 concepts is proposed for future testing and discussion.
Assessment of persistency and bioaccumulation in pesticide registration frameworks within the organization for economic cooperation and development
Authors: Montforts Mark H. M. M.
Published: March 2010

This article describes the results of a survey conducted in 2003 on methods used by different member countries within the Organization for Economic Cooperation and Development (OECD) to evaluate persistent and bioaccumulative pesticides. The objectives were to establish the differences in taking persistence (P) and bioaccumulation (B) into account in the decision-making process and to establish the influence of the assessors' subjectivity to data interpretation and data selection. Fifteen countries participated in the survey, which generated a vast amount of information on decision making, risk assessment, risk classification, and data treatment. Survey results indicated clear differences in approaches to the use of P, B, and toxicity (T) information in scientific risk assessment. Using the same data for 2 different pesticides, several OECD member countries responded differently in classifying both substances as P, B, and T. Differences in regulatory decision-making were also apparent because, based on identical classifications, several OECD member countries adopted different decisions on pesticide registration; recommendations were based, with respect to technical guidance, on data handling, training of assessors, and handling of uncertainty in risk assessment.
Background levels of metals in St. Lawrence river sediments: Implications for sediment quality criteria and environmental management
Authors: Saulnier Isabelle , Gagnon Christian
Published: March 2010

Preindustrial sediments dredged from the St. Lawrence Seaway are often considered potentially toxic relative to interim sediment quality criteria. The aim of the present study was to better document the background levels of target metals that were once used to define the minimal threshold of these criteria. Three extractions were performed on sediment samples to evaluate the distribution and potential bioavailability of trace metals. The results showed that the background levels established for the criteria are representative of contaminant concentrations observed in preindustrial sediments but not of the postglacial marine clays underlying these sediments. Chromium, nickel, and copper concentrations in postglacial marine clays, when solubilized by strong acids, exceeded the minimal effect threshold, whereas chromium and nickel frequently exceeded the toxic effect threshold and therefore are problematic in terms of applying sediment quality assessment criteria. The results suggest that these trace metals are mostly associated with inert silicates in postglacial marine clays and are unlikely to be bioavailable to aquatic organisms. Postglacial marine clays should be better considered differently than are sediments in regard to the sediment quality criteria implementation. Accordingly, the use of tools to identify the postglacial material may become necessary if a particular management disposition should be established for this sedimentary material. Total recoverable aluminum concentrations in sediments, in conjunction with other physical characteristics, was shown to be an interesting tool to identify this specific material. The normalization of metals concentrations with total recoverable aluminum concentrations would take account of natural mineralogical and textural variability of freshwater sediments in the quality assessment process.
Ecology in a cost-benefit society: The issues
Authors: Forbes Valery E. , Calow Peter
Published: March 2010

Is there a role for ecology in a cost-benefit society? As a prelude to a collection of papers arising from a conference on this theme held at Roskilde University in June 2004, this paper summarizes divergent approaches to public policy decision making. Whether based on strict cost-benefit analysis or wide-ranging discussion, we make the point that decisions need to be informed by an understanding of the causes behind environmental problems and their consequences, through impaired ecosystem services, on the economy. Taking this forward will require forums that bring ecologists, economists, and regulators into active and constructive dialogue.
Thinking broadly about costs and benefits in ecological management
Authors: Costanza Robert
Published: March 2010

Decisions regarding both human and natural systems often involve either explicit or implicit consideration of relative costs and benefits. These costs and benefits, however, go well beyond those captured in conventional economic cost-benefit analysis. It is not so much the mere consideration of costs and benefits that hampers cost-benefit analysis but, rather, the narrowness and incompleteness of the subset of costs and benefits that are usually considered. To use cost-benefit analysis for social decision making, one needs to think very broadly about which categories of costs and benefits need to be addressed (including effects on built, human, social, and natural capital as well as sustainable well-being) and deal with the inherent uncertainty and imprecision attached to many of the more important categories. One needs to consider the full range of possible values and valuation methods, to shift the burden of proof to the parties that stand to gain from the decision, to deal with the distributional consequences of decisions, and to be clear about the social goals being served by the decision. Failure to think broadly enough about costs and benefits leads to decisions that serve only narrow special interests, not the sustainable well-being of society as a whole.
Decision support–oriented selection of remediation technologies to rehabilitate contaminated sites
Authors: Critto Andrea , Cantarella Lisa , Carlon Claudio , Giove Silvio , Petruzzelli Gianniantonio , Marcomini Antonio
Published: March 2010

A methodology for selecting remediation technologies is presented as part of a decision support system for the rehabilitation of contaminated sites. It includes 2 steps: In the 1st step, a pool of suitable technologies is selected within a technologies database according to their applicability to site-specific conditions; in the 2nd step, the selected technologies are ranked according to a multicriteria decision analysis (MCDA) approach. The MCDA was applied to allow for a transparent procedure and for the integration of expert analyses. The methodology was implemented in a previously developed georeferenced information system–based decision support system for the rehabilitation of contaminated sites and then applied to a case study (Porto Marghera, Venice, Italy). On the basis of the obtained results, the proposed methodology appeared suitable to select remediation technologies according to both technical features and requirements of available technologies, as well as site-specific environmental conditions of the site of concern, such as chemical contamination levels and remediation objectives.
Potential of dark-striped field mice, Apodemus agrarius coreae, for use as a biological radiation dosimeter for human environments
Authors: Kim Hee-sun , Nishimura Yoshikazu , Kim Chong-soon
Published: March 2010

This study examined the possibility of using striped field mice as a biological dosimeter or indicator for surveillance of the ecological effects of boundary radiation emitted by nuclear power plants. For this study, the external morphological characteristics and isoenzymic electrophoretypes of Korean domestic dark-striped field mice were studied after they were captured, controlled for reproduction, and their exact species were identified. In terms of morphological external characteristics, the dark-brown coat, dark back stripe, head-to-tail length, tail length, and ear length matched the taxonomical characteristics of dark-striped field mice. In terms of isoenzymic electrophoretypes, the analyses on l-lactate dehydrogenase, aspartate aminotransferase, and malate dehydrogenase revealed that one species of dark-striped field mice, called Apodemus agrarius coreae, was scattered throughout a wide range of habitats. On the other hand, after irradiating the A. a. coreae (0, 0.5, 1, 3, 5, and 7 gray [Gy]) to analyze their survival rate and frequency of micronuclei in peripheral polychromatic erythrocytes, their LD50/30 was approximately 5 Gy. Also, the mice that contained 1 or 3 Gy gained weight compared with those that contained 0.5 Gy. Moreover, those with 0.5 Gy and higher showed an increase in white blood cells and platelets as well as in sodium and creatinine. However, decreased concentrations of alkaline phosphatase, alanine animotransferase, calcium, phosphorus, and globulin were observed in the A. a. coreae after irradiation. The results of the study reveal that wild A. a. coreae mice have high potential as a biological monitoring system to determine radiation effects in human environments such as those within the vicinity of nuclear power plants.
Stochastic probability modeling to predict the environmental stability of nanoparticles in aqueous suspension
Authors: Mackay Christopher E , Johns Mark , Salatas Johanna H , Bessinger Brad , Perri Monica
Published: March 2010

The term “nanomaterial” describes a preparation in which the particle size is on the order of 10 to 100 nm in diameter. Such particles have the ability to form suspensions in fluid media such as air and water that can dramatically increase the environmental transport potential in comparision with like materials of larger particle sizes. Quantifying such transport requires an ability to predict the stability of such suspensions as to their tendency to aggregate or interact with other environmental constituents. In this paper, we present a method for predicting the magnitude and uncertainty associated with nanoparticle suspension stability. The critical buoyancy properties are predicted using the Boltzmann equation. The rates of aggregation are then predicted on the basis of molecular collision and adhesion coefficients. The progress of particle growth is simulated across all potential pathways probabalistically using the Gillespie model to characterize the uncertainty. Discussion is provided regarding potential environmental applications and further potential development in predicting particle behavior and effects on the environment.
Aquatic risks of pesticides, ecological protection goals, and common aims in european union legislation
Authors: Brock Theo CM , Arts Gertie HP , Maltby Lorraine , Van den Brink Paul J
Published: March 2010

This discussion paper presents a framework for spatiotemporal differentiation in ecological protection goals to assess the risks of pesticides in surface waters. It also provides a proposal to harmonize the different scientific approaches for ecotoxicological effect assessment adopted in guidance documents that support different legislative directives in the European Union (Water Framework Directive and Uniform Principles). Decision schemes to derive maximum permissible concentrations in surface water are presented. These schemes are based on approaches recommended in regulatory guidance documents and are scientifically underpinned by critical review papers concerning the impact of pesticides on freshwater organisms and communities. Special attention is given to the approaches based on standard test species, species sensitivity distribution curves, and model ecosystem experiments. The decision schemes presented here may play a role in the “acceptability” debate and can be used as options in the process of communication between risk assessors and risk managers as well as between these risk experts and other stakeholders.
Characterizing the risks to aquatic ecosystems: A tentative approach in the context of freshwater dredged material disposal
Authors: Babut Marc P. , Delmas Hélène , Bray Marc , Durrieu Claude , Perrodin Yves , Garric Jeanne
Published: March 2010

The development of relevant frameworks for assessing ecological risks posed by dredged material management does not only involve an appropriate selection of assessment and measurement endpoints but also requires a sound approach to both risk characterization and the associated uncertainty. A formal methodology addressing both aspects has been developed in France for freshwater sediment deposits in water. Both exposure and effects measurements are 1 st transformed into scores or classes. As far as possible, class boundaries are based on existing knowledge or expertise. Benthic organism exposure is based on a ratio of the deposit area to the burrow pit area, whereas pelagic species exposure is based on the ratio of porewater volume to water column volume. The combination of exposure and effect scores yields risk scores, or classes, which are linked to management decisions. Uncertainty is assessed with respect to a set of 4 predetermined criteria for exposure (the strength of association with the assessment endpoint, spatial and temporal representativeness, and the use of standard methods) and 4 criteria for effects (strength of association, the distinction between effect and no effect, sensitivity, and the use of standard methods). This approach was applied to 8 sediments from French canals contaminated to varying degrees.
Total and inorganic arsenic in mid-atlantic marine fish and shellfish and implications for fish advisories
Authors: Greene Richard , Crecelius Eric
Published: March 2010

Sampling was conducted in 2002 to determine the total concentration and chemical speciation of arsenic in several marine fish and shellfish species collected from the Delaware Inland Bays and the Delaware Estuary, both of which are important estuarine waterbodies in the US Mid-Atlantic region that support recreational and commercial fishing. Edible meats from summer flounder (Paralicthys dentatus), striped bass (Marone saxatilis), Atlantic croaker (Micropogonias undulates), and hard clam (Mercenaria mercenaria) were tested. Total arsenic was highest in summer flounder, followed by hard clam, then striped bass, and finally, Atlantic croaker. Total arsenic was higher in summer flounder collected during the spring, as these fish migrated into the Inland Bays from the continental shelf, compared with levels in summer flounder collected during the fall, after these fish had spent the summer in the Inland Bays. Similarly, striped bass collected in the early spring close to the ocean had higher total arsenic levels compared with levels detected in striped bass collected later during the year in waters with lower salinity. Speciation of arsenic revealed low concentrations (0.00048–0.02 μg/g wet wt) of toxic inorganic arsenic. Dimethylarsinic acid was more than an order of magnitude greater in hard clam meats than in the other species tested, a finding that was attributed to arsenic uptake by phytoplankton and subsequent dietary uptake by the clam. Risk assessment using the inorganic arsenic concentrations was used to conclude that a fish consumption advisory is not warranted.
The value of metals bioavailability and speciation information for ecological risk assessment in arid soils
Authors: Suedel Burton C , Nicholson Andrew , Day Christopher H , Spicer James
Published: March 2010

When evaluating the risk chemicals may pose to mammals and birds in ecological risk assessments (ERAs), it is common practice to conservatively assume that all (100%) of a chemical in an environmental medium is bioavailable to receptors. This assumption often leads to overestimating ecological risk and may ultimately result in costly and unnecessary risk management actions. While effects of bioavailability and speciation of metals such as arsenic (As) and lead (Pb) have been considered in human health risk assessment, these effects are rarely taken into consideration when assessing risks to mammals and birds. An ERA was conducted at the former Col-Tex refinery site in Colorado City, Texas, USA, to characterize risks to select wildlife species from exposure to chromium (Cr) and Pb found in soils. The focus on these metals was based on results of a screening-level ERA that found that Cr and Pb were posing ecological risks at the site. Soils were analyzed for total Cr and Pb, trivalent Cr (CrIII), hexavalent Cr (CrVI), organic Pb, and the bioavailability and speciation of Pb. Results for Pb and Cr indicated that >94% of the Cr was present as the less toxic and immobile Cr(lll) and that >99% of the Pb in soils was present as inorganic Pb. Lead bioaccessibility measured by in vitro testing ranged from 8% to 77.8%, depending on location of individual soil samples. Results demonstrated that Pb and Cr bioavailability and speciation information can raise soil cleanup concentrations while being protective of ecological receptors. The costs of performing the ERA were de minimus compared to the reduction in remediation costs at the site. The refined hazard estimates allowed informed decision making in the management and segregation of soils, allowing for effective risk management at the site.
Dermally adhered soil: 1. Amount and particle-size distribution
Authors: Choate LaDonna M , Ranville James F , Bunge Annette L , Macalady Donald L
Published: March 2010

The risk associated with the dermal absorption of chemicals from contaminated soil is, in part, a function of particle size distribution, as determined by either dry or wet sieving techniques. For the soils tested, the adhered soil fractions were shown to be independent of organic matter content and soil origin. Soil moisture content becomes a factor only for very moist soils. Results show that the adhered fractions of dry or moderately moist soils with wide distributions of particle sizes generally consist of particles of diameters <63 μm. Consequently, dermal absorption experiments using larger size fractions may be of limited relevance to actual situations of soil exposure.
Dermally adhered soil: 2. Reconstruction of dry-sieve particle-size distributions from wet-sieve data
Authors: Choate LaDonna M , Ranville James F , Bunge Annette L , Macalady Donald L
Published: March 2010

In the evaluation of soil particle-size effects on environmental processes, particle-size distributions are measured by either wet or dry sieving. Commonly, size distributions determined by wet and dry sieving differ because some particles disaggregate in water. Whereas the dry-sieve distributions are most relevant to the study of soil adherence to skin, soil can be recovered from skin only by washing with the potential for disaggregation whether or not it is subsequently wet or dry sieved. Thus, the possibility exists that wet-sieving measurements of the particle sizes that adhered to the skin could be skewed toward the smaller fractions. This paper provides a method by which dry-sieve particle-size distributions can be reconstructed from wet-sieve particle-size distributions for the same soil. The approach combines mass balances with a series of experiments in which wet sieving was applied to dry-sieve fractions from the original soil. Unless the soil moisture content is high (i.e., greater than or equal to the water content after equilibration with water-saturated air), only the soil particles of diameters less than about 63 μm adhere to the skin. Because of this, the adhering particle-size distribution calculated using the reconstruction method was not significantly different from the wet-sieving determinations.
Nanotechnologies: Tools for sustainability in a new wave of water treatment processes
Authors: Bottero Jean-Yves , Rose Jerome , Wiesner Mark Robert
Published: March 2010

In the environmental technology industry alone, nanomaterials will enable new means of reducing the production of industrial wastes, using resources more sparingly, remediating industrial contamination, providing potable water, and improving the efficiency of energy production. This paper discusses three new kinds of nanotechnology materials that should be developed in the future: Membranes, oxidants, and adsorbents. Nanoscale control of membrane architecture may yield membranes of greater selectivity and lower cost in both water treatment and water fabrication. Fullerene-based oxidant nanomaterials such as C60 have a high electron affinity and reactivity, and are capable of producing reactive oxygen species such as singlet oxygen and superoxides. Fullerenes might be used in engineered systems to photocatalytically oxidize organic contaminants, or inhibit or inactivate microbes. The ability to tailor surfaces can help to increase adsorbing capacities or recognize specific contaminants. The potential environmental risks are that nanomaterials could interact with biota and that their toxicity adversely may affect ecosystems. As nanochemistry emerges as an important force behind new environmental technologies, we are also presented with the responsibility of considering the environmental implications of an emerging technology at its inception and taking every precaution to ensure that these technologies develop as tools of sustainability rather than becoming future liabilities.
Evaluation of population-level ecological risks of dioxin-like polychlorinated biphenyl exposure to fish-eating birds in Tokyo Bay and its vicinity
Authors: Naito Wataru , Murata Mariko
Published: March 2010

Population-level assessments of the ecological risks of dioxin-like polychlorinated biphenyl (PCB) exposure to fish-eating birds in Tokyo Bay and its vicinity were performed to judge the need for risk management measures to protect aquatic wildlife from dioxin-like PCB contamination. Egg mortality risk and changes in the population growth rate (λ) in relation to the contamination levels of dioxin-like PCBs in eggs of gray heron (Ardea cinerea), great cormorant (Phalacrocorax carbo), osprey (Pandion halieaetus), and kingfisher (Alcedo atthis) were determined by integrating the results of exposure analysis, effect analysis, and a life-history model for each species. The egg mortality risks for the gray heron, great cormorant, osprey, and kingfisher populations were calculated to be 5.8, 6.8, 12, and less than 1%, respectively. The estimated λ for those populations were calculated to be 1.061, 1.405, 1.024, and 1.131, respectively. The percentage changes in λ for those populations were estimated to be 1.2, 2.0, 1.6, and less than 1%, respectively. Our results implied that the levels of dioxin-like PCBs observed in the Tokyo Bay area alone would not have significant population-level effects on the fish-eating bird populations. It is concluded that along with the trend toward decreasing dioxin and dioxin-like PCB levels in Tokyo Bay, no urgent need exists for risk-reduction measures to protect fish-eating bird populations against dioxin-like PCBs.
Relative toxicity and occurrence patterns of pesticide mixtures in streams draining agricultural watersheds dominated by corn and soybean production
Authors: Belden Jason B , Gilliom Robert J , Martin Jeffrey D , Lydy Michael J
Published: March 2010

To evaluate the relative toxicity and the occurrence patterns of pesticide mixtures in streams draining agricultural watersheds, a 3-step approach was used. First, a landscape of interest was identified, defined, and isolated. Second, the relative toxicity of mixtures, on the basis of pesticide toxicity index scores, was compared with the relative toxicity of the highest individual pesticide, on the basis of highest toxicity quotient values. Third, occurrence patterns of pesticide mixtures were identified for use in follow-up mechanistic studies. The landscape of interest was identified as the corn and soybeans crop setting and concentrations of pesticides in streams within this crop setting were determined from US Geological Survey data. Pesticide toxicity index scores for individual samples were highest for the primary producers, Pseudokirchneriella subcapitata and Lemna gibba; with 95th percentile pesticide toxicity index scores of 4.7 and 1.9, respectively. The 95th percentile pesticide toxicity index score for Daphnia magna was 0.40 when a chronic sublethal endpoint was used. Pesticide toxicity index values were above the highest toxicity quotient values, indicating that consideration of mixtures does increase the estimated risk, but pesticide toxicity index scores were generally within a factor of 2 of highest toxicity quotient values, indicating that the increased risk is not large for most samples. Pesticide toxicity index scores tended to be dominated by individual pesticides and simple mixtures. Two different prioritization strategies were used to identify important mixtures for further study on the basis of potential effects on P. subcapitata. Both techniques decreased the complexity of the pesticide mixtures to consider by reducing the number of components within the identified mixtures as well as identifying a few specific combinations that constitute the majority of mixtures within the sample. Nearly all important pesticides for P. subcapitata were herbicides from 2 chemical classes: Acetanilide and triazine herbicides.
Probability-based estimates of site-specific copper water quality criteria for the Chesapeake Bay, USA
Authors: Arnold W Ray , Warren-Hicks William J
Published: March 2010

The object of this study was to estimate site- and region-specific dissolved copper criteria for a large embayment, the Chesapeake Bay, USA. The intent is to show the utility of 2 copper saltwater quality site-specific criteria estimation models and associated region-specific criteria selection methods. The criteria estimation models and selection methods are simple, efficient, and cost-effective tools for resource managers. The methods are proposed as potential substitutes for the US Environmental Protection Agency's water effect ratio methods. Dissolved organic carbon data and the copper criteria models were used to produce probability-based estimates of site-specific copper saltwater quality criteria. Site- and date-specific criteria estimations were made for 88 sites (n = 5,296) in the Chesapeake Bay. The average and range of estimated site-specific chronic dissolved copper criteria for the Chesapeake Bay were 7.5 and 5.3 to 16.9 μg Cu/L. The average and range of estimated site-specific acute dissolved copper criteria for the Chesapeake Bay were 11.7 and 8.3 to 26.4 μg Cu/L. The results suggest that applicable national and state copper criteria can increase in much of the Chesapeake Bay and remain protective. Virginia Department of Environmental Quality copper criteria near the mouth of the Chesapeake Bay, however, need to decrease to protect species of equal or greater sensitivity to that of the marine mussel, Mytilus sp.
The integration of ecological risk assessment and structured decision making into watershed management
Authors: Ohlson Dan W , Serveiss Victor B
Published: March 2010

Watershed management processes continue to call for more science and improved decision making that take into account the full range of stakeholder perspectives. Increasingly, the core principles of ecological risk assessment (i.e., the development and use of assessment endpoints and conceptual models, conducting exposure and effects analysis) are being incorporated and adapted in innovative ways to meet the call for more science. Similarly, innovative approaches to adapting decision analysis tools and methods for incorporating stakeholder concerns in complex natural resource management decisions are being increasingly applied. Here, we present an example of the integration of ecological risk assessment with decision analysis in the development of a watershed management plan for the Greater Vancouver Water District in British Columbia, Canada. Assessment endpoints were developed, ecological inventory data were collected, and watershed models were developed to characterize the existing and future condition of 3 watersheds in terms of the potential risks to water quality. Stressors to water quality include sedimentation processes (landslides, streambank erosion) and forest disturbance (wildfire, major insect or disease outbreak). Three landscape-level risk management alternatives were developed to reflect different degrees of management intervention. Each alternative was evaluated under different scenarios and analyzed by explicitly examining value-based trade-offs among water quality, environmental, financial, and social endpoints. The objective of this paper is to demonstrate how the integration of ecological risk assessment and decision analysis approaches can support decision makers in watershed management.
Environmental management with knowledge of uncertainty: A methylmercury case study
Authors: Hope Bruce K , Lut Agnes , Aldrich Greg , Rubin Jared
Published: March 2010

In Oregon's Willamette River Basin, health advisories currently limit consumption of fish that have accumulated methylmercury to levels posing a potential health risk for humans. Under the Clean Water Act, these advisories represent an impairment of the beneficial use of fish consumption and create the requirement for a mercury total maximum daily load. A percent load reduction for total mercury was determined by comparing mercury levels in surface water to a water column guidance value linked to the protection of specified beneficial uses. In this case study, we discuss how probabilistic (Monte Carlo) methods were used to quantify uncertainty in the water column guidance value, how they provided decision makers with knowledge as to the probability of any given water column guidance value affording human health protection for methylmercury, and how this knowledge affected decisions as to a mercury load reduction for the Willamette River Basin. Through consultations with stakeholders, a water column guidance value of 0.92 ng/L (a median for higher trophic level fish) was chosen from among a suite of values of differing probabilities. The selected water column guidance value, when compared with ambient total mercury levels, indicated that a 50% probability of achieving the tissue criterion would require a load reduction of about 26%. Having and working with an explicit knowledge of uncertainty was not easy for many decision makers or stakeholders. However, such knowledge gave them more informed choices, a better understanding of what a specific choice of water column guidance value could mean in terms of achieving protectiveness, and led to a lower load reduction than suggested by a purely deterministic analysis. Nonetheless, more attention must be given to developing management, communication, and regulatory frameworks that can effectively use the greater knowledge of uncertainty afforded by probabilistic methods.