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Ecological Risk Assessment (ecological + risk_assessment)

Distribution by Scientific Domains

Life Sciences	45%

Selected Abstracts

Trait-based ecological risk assessment (TERA): The new frontier?

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2008
Donald J Baird
Traits describe the physical characteristics, ecological niche, and functional role of species within ecosystems, and trait-based approaches are now being introduced into the field of Ecological Risk Assessment (ERA). The costs and benefits arising from the adoption of these approaches in the assessment of risks from toxic substances are described, and the path forward for this new frontier in risk assessment science is presented. In particular, the necessity for more open collaboration and web-based data-sharing to facilitate the development of these exciting new tools is stressed, and the role of scientific organizations such as SETAC as promoters of this ambitious program is highlighted. [source]

Ecological risk assessment of persistent toxic substances for the clam Tapes philipinarum in the lagoon of venice, italy

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2004
Christian Micheletti
Abstract Because of contamination of sediments of the Lagoon of Venice, Italy, by inorganic pollutants (e.g., arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc) and organic pollutants (e.g., polychlorobiphenyls), as well as the ecological and economical relevance of the edible clam Tapes philipinarum, an ecological risk assessment was undertaken to ascertain the extent of bioaccumulation that would pose a significant risk. Risk was estimated by means of toxic units and hazard quotient approaches, by comparing the exposure concentration with the effect concentration. Clam exposure was estimated by applying previous results based on bioaccumulation spatial regression models. In addition, a comparison was made between sum of dioxin-like polychlorinated biphenyl (PCB) congeners and total PCB bioaccumulation provided by spatial regression models and by a partitioning model. The effect concentrations were calculated as tissue screening concentrations, as the product of pollutant sediment quality criteria and the bioaccumulation factor. Finally, the cumulative risk posed by selected inorganic pollutants and total PCBs was estimated and a map of risk was drawn. The resulting chemicals of potential ecological concern were mercury, cadmium, arsenic, and nickel, as well as, to a lesser extent, total PCBs. [source]

Ecological risk assessment, 2nd edition by Glenn W. Suter II

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2008
Richard Wenning Editor-in-Chief
No abstract is available for this article. [source]

Using a Geographic Information System to identify areas with potential for off-target pesticide exposure

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006
Thomas G. Pfleeger
Abstract In many countries, numerous tests are required as part of the risk assessment process before chemical registration to protect human health and the environment from unintended effects of chemical releases. Most of these tests are not based on ecological or environmental relevance but, rather, on consistent performance in the laboratory. A conceptual approach based on Geographic Information System (GIS) technology has been developed to identify areas that are vulnerable to nontarget chemical exposure. This GIS-based approach uses wind speed, frequency of those winds, pesticide application rates, and spatial location of agricultural crops to identify areas with the highest potential for pesticide exposure. A test scenario based on an incident in Idaho (USA) was used to identify the relative magnitude of risk from off-target movement of herbicides to plants in the conterminous United States. This analysis indicated that the western portion of the Corn Belt, the central California valley, southeastern Washington, the Willamette Valley of Oregon, and agricultural areas bordering the Great Lakes are among those areas in the United States that appear to have the greatest potential for off-target movement of herbicides via drift. Agricultural areas, such as the Mississippi River Valley and the southeastern United States, appears to have less potential, possibly due to lower average wind speeds. Ecological risk assessments developed for pesticide registration would be improved by using response data from species common to high-risk areas instead of extrapolating test data from species unrelated to those areas with the highest potential for exposure. [source]

An overview of the use of quantitative structure-activity relationships for ranking and prioritizing large chemical inventories for environmental risk assessments

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2003
Christine L. Russom
Abstract Ecological risk assessments for chemical stressors are used to establish linkages between likely exposure concentrations and adverse effects to ecological receptors. At times, it is useful to conduct screening risk assessments to assist in prioritizing or ranking chemicals on the basis of potential hazard and exposure assessment parameters. Ranking of large chemical inventories can provide evidence for focusing research and/or cleanup efforts on specific chemicals of concern. Because of financial and time constraints, data gaps exist, and the risk assessor is left with decisions on which models to use to estimate the parameter of concern. In this review, several methods are presented for using quantitative structure-activity relationships (QSARs) in conducting hazard screening or screening-level risk assessments. The ranking methods described include those related to current regulatory issues associated with chemical inventories from Canada, Europe, and the United States and an example of a screening-level risk assessment conducted on chemicals associated with a watershed in the midwest region of the United States. [source]

Uptake kinetics and subcellular compartmentalization of cadmium in acclimated and unacclimated earthworms (Eisenia andrei)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2010
Shuo Yu
Abstract Acclimation to cadmium (Cd) levels exceeding background concentrations may influence the ability of earthworms to accumulate Cd with minimum adverse effects. In the present study, earthworms (Eisenia andrei) were acclimated by exposure to 20,mg/kg Cd (dry wt) in Webster soil for 28 d. A 224-d bioaccumulation test was subsequently conducted with both acclimated and unacclimated worms exposed in Webster soils spiked with 20,mg/kg and 100,mg/kg Cd (dry wt). Uptake kinetics and subcellular compartmentalization of Cd were examined. Results suggest that acclimated earthworms accumulated more Cd and required a longer time to reach steady state than unacclimated worms. Most of the Cd was present in the metallothionein (MT) fraction. Cadmium in the MT fraction increased approximately linearly with time and required a relatively longer time to reach steady state than Cd in cell debris and granule fractions, which quickly reached steady state. Cadmium in the cell debris fraction is considered potentially toxic, but low steady state concentrations observed in the present study would not suggest the potential for adverse effects. Future use of earthworms in ecological risk assessment should take into consideration pre-exposure histories of the test organisms. A prolonged test period may be required for a comprehensive understanding of Cd uptake kinetics and compartmentalization. Environ. Toxicol. Chem. 2010;29:1568,1574. © 2010 SETAC [source]

Adverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessment

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010
Gerald T. Ankley
Abstract Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk,effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework. Environ. Toxicol. Chem. 2010;29:730,741. © 2009 SETAC [source]

The extrapolation problem and how population modeling can help,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2008
Valery E. Forbes
Abstract We argue that population modeling can add value to ecological risk assessment by reducing uncertainty when extrapolating from ecotoxicological observations to relevant ecological effects. We review other methods of extrapolation, ranging from application factors to species sensitivity distributions to suborganismal (biomarker and "-omics") responses to quantitative structure,activity relationships and model ecosystems, drawing attention to the limitations of each. We suggest a simple classification of population models and critically examine each model in an extrapolation context. We conclude that population models have the potential for adding value to ecological risk assessment by incorporating better understanding of the links between individual responses and population size and structure and by incorporating greater levels of ecological complexity. A number of issues, however, need to be addressed before such models are likely to become more widely used. In a science context, these involve challenges in parameterization, questions about appropriate levels of complexity, issues concerning how specific or general the models need to be, and the extent to which interactions through competition and trophic relationships can be easily incorporated. [source]

Neuropharmaceuticals in the environment: Mianserin-induced neuroendocrine disruption in zebrafish (Danio rerio) using cDNA microarrays

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2006
Karlijn van der Ven
Abstract Because of their environmental occurrence and high biological activity, human pharmaceuticals have received increasing attention from environmental and health agencies. A major bottleneck in their risk assessment is the lack of relevant and specific effect data. We developed an approach using gene expression analysis in quantifying adverse effects of neuroendocrine pharmaceuticals in the environment. We studied effects of mianserin on zebrafish (Danio rerio) gene expression using a brain-specific, custom microarray, with real-time polymerase chain reaction as confirmation. After exposure (0, 25, and 250 ,g/L) for 2, 4, and 14 d, RNA was extracted from brain tissue and used for microarray hybridization. In parallel, we investigated the impact of exposure on egg production, fertilization, and hatching. After 2 d of exposure, microarray analysis showed a clear effect of mianserin on important neuroendocrine-related genes (e.g., aromatase and estrogen receptor), indicating that antidepressants can modulate neuroendocrine processes. This initial neuroendocrine effect was followed by a "late gene expression effect" on neuronal plasticity, supporting the current concept regarding the mode of action for antidepressants in mammals. Clear adverse effects on egg viability were seen after 14 d of exposure at the highest concentration tested. Based on the specific molecular impact and the effects on reproduction, we conclude that further investigation of the adverse effects on the brain-liver-gonad axis is needed for a correct ecological risk assessment of antidepressants. [source]

Evaluating the contribution of soil properties to modifying lead phytoavailability and phytotoxicity,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2006
Elizabeth A. Dayton
Abstract Soil properties affect Pb bioavailability to human and ecological receptors and should be considered during ecological risk assessment of contaminated soil. We used path analysis (PA) to determine the relative contribution of soil properties (pH, organic C [OC], amorphous Fe and Al oxides [FEAL], and cation-exchange capacity [CEC]) in modifying Pb bioavailability. The response of biological endpoints (bioaccumulation and dry matter growth [DMG]) of lettuce (Lactuca sativa) grown on 21 Pb-spiked (2,000 mg/kg) soils were determined. Lettuce tissue Pb ranged from 3.22 to 233 mg/kg, and relative DMG ranged from 2.5 to 88.5% of their respective controls. Simple correlation showed strong relationships between CEC and OC (p < 0.01) and weaker relationships between pH and FEAL (p < 0.05) and Pb bioaccumulation. Results of PA suggest that soil pH increased the negative surface charge of organic matter and clay, thereby increasing CEC and decreasing Pb bioaccumulation. Also, the direct effect of OC on tissue Pb can be attributed to formation of surface Pb complexes by organic matter functional group ligands. Increased OC and/or CEC reduced Pb solubility and bioavailability in the 21 soils in the present study. The relative importance of soil properties likely will vary between studies employing different soils. Soil properties should be considered during the ecological risk assessment of metal in contaminated soils. Path analysis is useful for ecological studies involving soils with a wide range of physicochemical properties and can assist in site risk assessment of metals and remediation decisions on contaminated sites. [source]

Ecological risk assessment of persistent toxic substances for the clam Tapes philipinarum in the lagoon of venice, italy

Among- and within-population variability in tolerance to cadmium stress in natural populations of Daphnia magna: Implications for ecological risk assessment

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2002
Carlos Barata
Abstract Previous attempts to test the hypothesis that laboratory selection of isogenetic populations can produce test organisms with a significantly increased mean tolerance to toxic substances have failed. One possible explanation for such failure is that the tolerance of laboratory populations is largely constrained by their origins (were the source populations composed of tolerant genotypes?). To address this question, among- and within-population variability in stress tolerance was assessed by calculating the variance in individual fitness and longevity across a cadmium gradient (0,10 ,g/L). The study employed Daphnia magna clones from four geographically separate European populations. Results revealed significant differences in tolerance to lethal levels of toxic stress among populations. The distribution of tolerances within two of the studied populations showed high amounts of genetic variation in tolerance. Genetic relationships between tolerance traits and life history performance under nonstressful environments differed among the studied populations. One population showed significant but low costs associated with tolerance, whereas no costs were associated with tolerance in the other population. These results suggest that laboratory selection will favor individuals with high fitness or reproductive performance under optimal laboratory conditions resulting in laboratory populations with similar or lower tolerance to toxic stress than their original field populations. Given that populations can exhibit high levels of genetic variability in tolerance to toxic stress, minimizing genetic diversity in toxicity tests will increase the uncertainty attendant in extrapolating from the lab to the field. [source]

A test of the community conditioning hypothesis: Persistence of effects in model ecological structures dosed with the jet fuel jp-8

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000
Wayne G. Landis
Abstract The foundation of the community conditioning hypothesis, the persistence of effects, was tested in a series of microcosm experiments. Experiments were conducted with the water-soluble fraction of the turbine fuel JP-8 using the standard protocols for the standardized aquatic microcosm (SAM). A repeat trial was conducted using the SAM protocol but with a 126-d test period, twice the standard duration. The results were examined using a variety of conventional univariate, multivariate, and graphical techniques. The principal conclusions were as follows. Effects are persistent in these model ecological systems long after the degradation of the toxicant. Patterns of impacts are detectable at concentrations 15 times lower than an experimentally derived single-species EC50. The replicate experiments are not replicable in the specific, but the broad pattern of the disruption of algal- herbivore dynamics followed by more subtle effects are consistently repeated. The durability of the indirect effects and therefore the information about historical events appears to be a consistent feature of these microcosm systems. The identity of the treatment groups persists. The critical features of the community conditioning hypothesis,persistence of information within ecologicalsystems and the reappearance of patterns and therefore the nonequilibrium dynamics,are again confirmed. The implications of these findings for environmental toxicology, monitoring, and ecological risk assessment are discussed. [source]

Applying species-sensitivity distributions in ecological risk assessment: Assumptions of distribution type and sufficient numbers of species,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000
Michael C. Newman
Abstract Species-sensitivity distribution methods assemble single-species toxicity data to predict hazardous concentrations (HCps) affecting a certain percentage (p) of species in a community. The fit of the lognormal model and required number of individual species values were evaluated with 30 published data sets. The increasingly common assumption that a lognormal model best fits these data was not supported. Fifteen data sets failed a formal test of conformity to a lognormal distribution; other distributions often provided better fit to the data than the lognormal distribution. An alternate bootstrap method provided accurate estimates of HCp without the assumption of a specific distribution. Approximate sample sizes producing HC5 estimates with minimal variance ranged from 15 to 55, and had a median of 30 species-sensitivity values. These sample sizes are higher than those suggested in recent regulatory documents. A bootstrap method is recommended that predicts with 95% confidence the concentration affecting 5% or fewer species. [source]

Perspectives on ecological risk assessment of chiral compounds

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 3 2009
Jacob K Stanley
Abstract Enantiomers of chiral contaminants can significantly differ in environmental fate as well as in effects. Despite this fact, such differences are often ignored in regulation and in practice, injecting uncertainty into the estimation of risk of chiral compounds. We review the unique challenges posed by stereochemistry to the ecological risk assessment of chiral contaminants and existing regulatory guidance for chiral pharmaceuticals and pesticides in the United States. We identify the advantages of obtaining data on fate and effects of each individual enantiomer of chiral contaminants that are either distributed as or may end up as enantiomer mixtures in the environment due to enantiomerization. Because enantiomers of the same compound are highly likely to coexist in the environment with each other and can result in nonadditive effects, we recommend treatment of enantiomers as components of a mixture using widely accepted mixture models from achiral risk assessment. We further propose the enantiomer hazard ratio for retrospectively characterizing relative enantiomer risk and examine uncertainty factor magnitudes for effects analysis. [source]

Temporal changes in contaminated sediment: A neglected aspect of ecological risk assessment?

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2008
Carol Stewart
No abstract is available for this article. [source]

Trait-based ecological risk assessment (TERA): The new frontier?

In situ-based effects measures: Determining the ecological relevance of measured responses

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 2 2007
Donald J Baird
Abstract The aim of this review is to examine how the choice of test species and study design employed in the use of in situ approaches in ecological risk assessment can maximize the ecological relevance of data. We provide a framework to define and assess ecological relevance that permits study designs to remain focused on the ecological question being addressed. This framework makes explicit the linkages between effects at lower levels of biological organization and higher-order ecological effects at the population, community, and ecosystem levels. The usefulness of this framework is illustrated by reference to specific examples from aquatic ecotoxicology. The use of models as both interpretive and predictive tools is discussed, with suggestions of appropriate methods for different protection goals. [source]

The integration of ecological risk assessment and structured decision making into watershed management

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2007
Dan W Ohlson
Abstract 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. [source]

Sequential analysis of lines of evidence,an advanced weight-of-evidence approach for ecological risk assessment

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006
Ruth N Hull
Abstract Weight-of-evidence (WOE) approaches have been used in ecological risk assessment (ERA) for many years. The approaches integrate various types of data (e.g., from chemistry, bioassay, and field studies) to make an overall conclusion of risk. However, the current practice of WOE has several important difficulties, including a lack of transparency related to how each line of evidence is weighted or integrated into the overall weight-of-evidence conclusion. Therefore, a sequential analysis of lines of evidence (SALE) approach has been developed that advances the practice of WOE. It was developed for an ERA of chemical stressors but also can be used for nonchemical stressors and is equally applicable to the aquatic and terrestrial environments. The sequential aspect of the SALE process is a significant advancement and is based on 2 primary ideas. First, risks can be ruled out with the use of certain lines of evidence, including modeled hazard quotients (HQs) and comparisons of soil, water, or sediment quality with conservative soil, water or sediment quality guidelines. Thus, the SALE process recognizes that HQs are most useful in ruling out risk rather than predicting risk to ecological populations or communities. Second, the SALE process provides several opportunities to exit the risk assessment process, not only when risks are ruled out, but also when magnitude of effect is acceptable or when little or no evidence exists that associations between stressors and effects may be causal. Thus, the SALE approach explicitly includes interaction between assessors and managers. It illustrates to risk managers how risk management can go beyond the simple derivation of risk-based concentrations of chemicals of concern to risk management goals based on ecological metrics (e.g., species diversity). It also can be used to stimulate discussion of the limitations of the ERA science, and how scientists deal with uncertainty. It should assist risk managers by allowing their decisions to be based on a sequential, flexible, and transparent process that includes direct toxicity risks, indirect risks (via changes in habitat suitability), and the spatial and temporal factors that can influence the risk assessment. [source]

Survey of methodologies for developing media screening values for ecological risk assessment

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2005
Mace G. Barron
Abstract This review evaluates the methodologies of 13 screening value (SV) compilations that have been commonly used in ecological risk assessment (ERA), including compilations from state and U.S. federal agencies, the Oak Ridge National Laboratory (ORNL), Canada, The Netherlands, and Australia. The majority of surfacewater SVs were primarily derived for the protection of aquatic organisms using 2 approaches: (1) a statistical assessment of toxicity values by species groupings, such as "ambient water quality criteria," or (2) extrapolation of a lowest observed adverse effect level determined from limited toxicity data using an uncertainty factor. Sediment SVs were primarily derived for the protection of benthic invertebrates using 2 approaches: (1) statistical interpretations of databases on the incidence of biological effects and chemical concentrations in sediment, or (2) values derived from equilibrium partitioning based on a surfacewater SV. Soil SVs were derived using a diversity of approaches and were usually based on the lowest value determined from soil toxicity to terrestrial plants or invertebrates and, less frequently, from modeled, incidental soil ingestion or chemical accumulation in terrestrial organisms. The various SV compilations and methodologies had varying levels of conservatism and were not consistent in the pathways and receptors considered in the SV derivation. Many SVs were derived from other compilations and were based on outdated values, or they relied on only older toxicity data. Risk assessors involved in ERA should carefully evaluate the technical basis of SVs and consider the uncertainty in any value used to determine the presence or absence of risk and the need for further assessment. [source]

How closely do acute lethal concentration estimates predict effects of toxicants on populations?

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 2 2005
John D. Stark
Abstract Acute lethal dose/concentration estimates are the most widely used measure of toxicity and these data often are used in ecological risk assessment. However, the value of the lethal concentration (LC50) as a toxicological endpoint for use in ecological risk assessment recently has been criticized. A question that has been asked frequently is how accurate is the LC50 for prediction of longer-term effects of toxicants on populations of organisms? To answer this question, Daphnia pulex populations were exposed to nominal concentrations equal to the 48-h acute LC50 of 6 insecticides, Actara, Aphistar diazinon, pymetrozine, Neemix, and Spinosad; and 8 agricultural adjuvants, Bond, Kinetic, Plyac, R-11, Silwet, Sylgard 309, Water Maxx, and X-77; for 10 d. None of the D. pulex populations exposed to the acute LC50 of these insecticides were 50% lower than the control populations at the end of the study; exposure to diazinon resulted in populations that were higher than expected (91% of the control). Exposure to Actara and Aphistar resulted in populations that were <1 and 29% of the control, respectively. Exposure to Fulfill, Neemix, and Spinosad resulted in extinction. Extinction occurred after exposure to all of the adjuvants, except Silwet L-77 where the population was 31% of the control. These results corroborate other studies that indicate that the LC50 is not a good predictor of effects on population growth. Although lethal concentration estimates have their place in toxicology, namely to compare intrinsic toxicity of chemicals among species or susceptibility of a species to different chemicals over short time periods, population growth and growth-rate studies are necessary to predict toxicant effects on populations. [source]

Assessing and managing contaminated sediments: Part I, developing an effective investigation and risk evaluation strategy

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2005
Sabine E. Apitz
Abstract This is the first of a two-part review of the current state-of-the-science pertaining to the assessment and management of contaminated sediments. The goal of this review is to introduce some of the major technical and policy issues stemming from the assessment and management of contaminated sediments, highlight a number of aspects of contaminated sediment assessment and management found to be successful, and, when appropriate, address the barriers that still exist for improving contaminated sediment management. In this paper, Part I, the many key elements of an effective investigation and risk evaluation strategy are reviewed, beginning with the development of a conceptual site model (CSM) and including a discussion of some of the key factors influencing the design of sediment investigations and ecological risk assessment of sediment-bound chemicals on aquatic biota. In Part II of this paper (Apitz et al. 2005), various approaches are reviewed for evaluating sediment risk and monitoring sediment remedy effectiveness. While many of the technical and policy issues described in this review are relevant to dredged material management, the focus of this paper is on sediment assessment for environmental management. [source]

An ecological risk assessment for spinosad use on cotton

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 1 2002
Cheryl B Cleveland
Abstract Spinosad is a reduced-risk insecticide with a novel mode of action that provides an alternative to older classes of insecticides such as organophosphates, carbamates and pyrethroids. A comprehensive ecological risk assessment for spinosad use in US cotton crops is presented within a framework of tiered levels of refinement following the guidelines of the US EPA for ecological risk assessments. Toxicity information for a variety of species is documented and utilized, environmental concentrations estimated, and risk characterizations in the form of risk quotients are quantified. Results indicate that spinosad use in cotton does not exceed the most conservative Tier I levels of concern (LOC) values for groundwater, mammals and birds or acute risk to aquatic organisms. Use of very conservative Tier I screening methods resulted in exceeding LOC values for chronic exposure for some aquatic organisms, thus prompting further refinement. When the exposure prediction was refined using less conservative, Tier II mechanistic environmental fate transport models to predict off-site transport and environmental concentrations, chronic risk was not predicted for these species. Spinosad is acutely toxic to bees under laboratory conditions, but toxicity of residue studies and field studies indicate that under actual use conditions the impact on bees is minimal. © 2001 Society of Chemical Industry [source]

Dose-related effects following oral exposure of 2,4-dinitrotoluene on the western fence lizard, Sceloporus occidentalis

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2008
Jamie G. Suski
Abstract 2,4-dintitrotoluene (2,4-DNT) is an explosive frequently found in the soil of military installations. Because reptiles can be common on these sites, ecological risk assessments for compounds such as 2,4-DNT could be improved with toxicity data specific to reptiles. Western fence lizards, Sceloporus occidentalis, were used to develop a laboratory toxicity model for reptiles. A hierarchical approach was used; acute to subchronic studies were conducted to provide toxicity data relevant to short- and long-term exposures. First, a modified median lethal dose (LD50) study was conducted on male and female lizards using a stage-wise probit model. The LD50 was 577 mg/kg for female and 380 mg/kg for male lizards. Subsequently, a subacute experiment was conducted to further assess 2,4-DNT toxicity to male lizards and to define exposure levels for a longer term, subchronic study. The subchronic study was conducted for 60 consecutive days; male lizards were exposed to 0, 9, 15, 25, 42, 70 mg/kg/d. Dose-dependent mortality was observed in the three highest dose groups (25, 42, and 70 mg/kg/d); all other animals survived the study duration. Benchmark dose model calculations based on mortality indicated a 5% effect level of 15.8 mg/kg/d. At study termination, a gross necropsy was performed, organ weights were taken, and blood was collected for clinical and hematological analysis. Body weight, kidney weight, food consumption, postdose observations, and blood chemistries all were found to be significantly different from controls at doses above 9 mg/kg/d. Also, preliminary results suggest behavioral observations, and reduced food consumption may be a sensitive indicator of toxicity. The present study indicates Sceloporus occidentalis is suitable for evaluating toxicity of compounds to reptilian species. [source]

Development and validation of a 2,000-gene microarray for the fathead minnow (Pimephales promelas)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2007
Patrick Larkin
Abstract Gene microarrays provide the field of ecotoxicology new tools to identify mechanisms of action of chemicals and chemical mixtures. Herein we describe the development and application of a 2,000-gene oligonucleotide microarray for the fathead minnow Pimephales promelas, a species commonly used in ecological risk assessments in North America. The microarrays were developed from various cDNA and subtraction libraries that we constructed. Consistency and reproducibility of the microarrays were documented by examining multiple technical replicates. To test application of the fathead minnow microarrays, gene expression profiles of fish exposed to 17,-estradiol, a well-characterized estrogen receptor (ER) agonist, were examined. For these experiments, adult male fathead minnows were exposed for 24 h to waterborne 17,-estradiol (40 or 100 ng/L) in a flow-through system, and gene expression in liver samples was characterized. Seventy-one genes were identified as differentially regulated by estradiol exposure. Examination of the gene ontology designations of these genes revealed patterns consistent with estradiol's expected mechanisms of action and also provided novel insights as to molecular effects of the estrogen. Our studies indicate the feasibility and utility of microarrays as a basis for understanding biological responses to chemical exposure in a model ecotoxicology test species. [source]

Copper toxicity thresholds for important restoration grass species of the western United States,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2002
Mark W.
Abstract Copper toxicity thresholds for plant species that are used in restoration activities in western North America have not been established. As a result, ecological risk assessments must rely on toxicity thresholds established for agronomic species, which usually differ from those of species used in restoration. Thus, risk assessors have the potential for classifying sites as phytotoxic to perennial, nonagronomic species and calling for intensive remediation activities that may not be necessary. The objective of this study was to provide a better estimate of Cu toxicity thresholds for five grass species that are commonly used in restoration efforts in the western United States. We used a greenhouse screening study where seedlings of introduced redtop (Agrostis gigantea Roth.), the native species slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners var. Pryor), tufted hairgrass (Deschampsia caespitosa [L.] Beauvois), big bluegrass (Poa secunda J. Presl var. Sherman), and basin wildrye (Leymus cinereus [Scribner&Merrill] A. Löve var. Magnar) and the agricultural species common wheat (Triticum aestivum L.) were grown in sand culture and exposed to supplemental concentrations of soluble Cu of 0 (control), 50, 100, 150, 200, 250, and 300 mg/L. We determined six measures of toxicity: the 60-d mean lethal concentration (LC50), 60-d mean effective concentration (EC50)-plant, 60-d EC50-shoot, 60-d EC50-root, phytotoxicity threshold (PT50)-shoot, and the PT50-root. Results suggest that these restoration grass species generally have higher Cu tolerance than agronomic species reported in the past. Of the species tested, redtop appeared to be especially tolerant of high levels of substrate and tissue Cu. Values of EC50-plant for restoration grasses were between 283 and 710 mg Cu/L compared to 120 mg Cu/L for common wheat. Measured PT50-shoot values were between 737 and 10,792 mg Cu/ L. These reported thresholds should be more useful for risk assessors than those currently used, which are based largely on agronomic crops. [source]

A logical starting point for developing priorities for lizard and snake ecotoxicology: A review of available data

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2002
Kym Rouse Campbell
Abstract Reptiles, specifically lizards and snakes, usually are excluded from environmental contamination studies and ecological risk assessments. This brief summary of available lizard and snake environmental contaminant data is presented to assist in the development of priorities for lizard and snake ecotoxicology. Most contaminant studies were not conducted recently, list animals found dead or dying after pesticide application, report residue concentrations after pesticide exposure, compare contaminant concentrations in animals from different areas, compare residue concentrations found in different tissues and organs, or compare changes in concentrations over time. The biological significance of the contaminant concentrations is rarely studied. A few recent studies, especially those conducted on modern pesticides, link the contaminant effects with exposure concentrations. Nondestructive sampling techniques for determining organic and inorganic contaminant concentrations in lizards and snakes recently have been developed. Studies that relate exposure, concentration, and effects of all types of environmental contaminants on lizards and snakes are needed. Because most lizards eat insects, studies on the exposure, effects, and accumulation of insecticides in lizards, and their predators, should be a top priority. Because all snakes are upper-trophic-level carnivores, studies on the accumulation and effects of contaminants that are known to bioaccumulate or biomagnify up the food chain should be the top priority. [source]

Uptake of inorganic chemicals from soil by plant leaves: Regressions of field data,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2001
Rebecca A. Efroymson
Abstract The estimation of chemical concentrations in wildlife foods, such as plant foliage, is often performed for risk assessments at contaminated sites. Regression models and uptake factors for use in estimating the uptake of inorganic elements from soil by above-ground plant tissues were derived in this study. These included models for arsenic, cadmium, copper, lead, mercury, nickel, selenium, and zinc. Models were developed using published data from soil contaminated in the field and were validated using measured concentrations from two contaminated sites. Single-variable regression models of log-transformed concentrations in plants versus log-transformed concentrations in soil are generally recommended over simple uptake factors for use in estimating plant uptake of inorganic contaminants in ecological risk assessments. Multiple regression models with soil concentration and pH as the variables are also recommended for estimating the uptake of four chemicals (cadmium, mercury, selenium, and zinc) by plants. Models for use in screening risk assessments, i.e., the upper 95% prediction limits on the regressions, are recommended to provide conservative estimates of uptake of inorganic chemicals by plants. [source]

Including species interactions in risk assessments for global change

GLOBAL CHANGE BIOLOGY, Issue 9 2007
R. W. SUTHERST
Abstract Most ecological risk assessments for global change are restricted to the effects of trends in climate or atmospheric carbon dioxide. In order to move beyond investigation of the effects of climate alone, the climexÔ model was extended to investigate the effects of species interactions, in the same or different trophic levels, along environmental gradients on a geographical scale. Specific needs that were revealed during the investigations include: better treatment of the effects of temporal and spatial climatic variation; elucidation of the nature of boundaries of species ranges; data to quantify the role of species traits in interspecies interactions; integrated observational, experimental, and modelling studies on mechanisms of species interactions along environmental gradients; and high-resolution global environmental datasets. Greater acknowledgement of the shared limitations of simplified models and experimental studies is also needed. Above all, use of the scientific method to understand representative species ranges is essential. This requires the use of mechanistic approaches capable of progressive enhancement. [source]