Showing papers in "Human and Ecological Risk Assessment in 2002"
TL;DR: Properly validated, PICT is a powerful tool for detection of community effects and its use in monitoring and site-specific risk assessment should be encouraged.
Abstract: Pollution-induced community tolerance (PICT) is used for the detection of minor effects of toxicants in biotic communities. Organisms survive in toxic environments only if they are tolerant to the chemicals present in their habitat. In the selection phase, toxicants hinder the success of sensitive individuals and species and replace them by more tolerant ones. The resulting increase in community tolerance is quantified in the detection phase by short-term toxicity tests. In this way PICT can establish causal linkages between contaminants and effects. An increase in community tolerance compared to the baseline tolerance at reference sites suggests that the community has been adversely affected by toxicants. PICT has been used in aquatic and terrestrial environments with communities of periphyton, phytoplankton, bacteria, nematodes and insects. A variety of methods have been used for quantification of community tolerance including photosynthesis, sulfolipid synthesis, respiration, thymidine and leucine inco...
302 citations
TL;DR: In this article, the authors revisited the assumptions associated with the derivation and application of species sensitivity distributions (SSDs) and concluded that SSDs clarify or obscure the setting of ecological effects thresholds for risk assessment.
Abstract: We revisit the assumptions associated with the derivation and application of species sensitivity distributions (SSDs). Our questions are (1) Do SSDs clarify or obscure the setting of ecological effects thresholds for risk assessment? and (2) Do SSDs reduce or introduce uncertainty into risk assessment? Our conclusions are that if we could determine a community sensitivity distribution, this would provide a better estimate of an ecologically relevant effects threshold and therefore be an improvement for risk assessment. However, the distributions generated are typically based on haphazard collections of species and endpoints and by adjusting these to reflect more realistic trophic structures we show that effects thresholds can be shifted but in a direction and to an extent that is not predictable. Despite claims that the SSD approach uses all available data to assess effects, we demonstrate that in certain frequently used applications only a small fraction of the species going into the SSD determine the ef...
256 citations
TL;DR: Overall, there is significant support for the genetic erosion hypothesis, but the issue cannot be considered settled and a concentrated research effort is necessary to better define the question and find a general approach to evaluate its importance in ecological risk assessment.
Abstract: The question whether environmental pollution affects genetic diversity in natural populations remains unanswered to date despite the fact that genetic variation is one of the three pillars of biodiversity recognized in the Rio convention of 1993. The loss of genetic diversity in populations subjected to anthropogenic stress can be designated as “genetic erosion” and may be considered as a factor of concern in risk assessment of toxic chemicals. Theoretically there are four different ways in which toxicants can affect genetic variation: (i) by increasing mutation rates, (ii) by directional selection on tolerant genotypes, (iii) by causing bottleneck events, and (iv) by altering migration. This paper reviews studies that have documented genetic change in animal populations exposed to environmental pollution. In these studies, genetic variation is measured in a variety of ways: heritability of quantitative characters, heterozygosity of allozyme loci, haplotype diversity in mitochondrial DNA, and variability ...
234 citations
TL;DR: Weight of evidence (WOE) frameworks for integrating and interpreting multiple lines of evidence are discussed, focusing on sediment quality assessments, and introducing a series of ten papers on WOE as mentioned in this paper.
Abstract: Weight of evidence (WOE) frameworks for integrating and interpreting multiple lines of evidence are discussed, focusing on sediment quality assessments, and introducing a series of ten papers on WOE. Approaches to WOE include individual lines of evidence (LOE) as well as combined LOE (indices, statistical summarization, logic systems, scoring systems, and best professional judgment [BPJ]). The application of WOE, based on multiple LOE, is discussed relative to the published literature. Fully implementing WOE requires consideration of six main LOE in sediment (or other assessments); these LOE generally correspond to other causality considerations including Koch's Postulates. However, the issue of sediment stability is an additional consideration, and the use of tabular decision matrices is recommended in a logic system to address LOE described by others as “analogy”, “plausibility”, or “logical and scientific sense.” Three examples of logic system WOE determinations based on the Sediment Quality Triad and ...
196 citations
TL;DR: A comprehensive multimedia assessment of the environmental fate of bisphenol A (BPA) is presented in this article, which includes an evaluation of relevant partitioning and reactive properties, estimation of discharge quantities in the U.S. and the European Union resulting in conservative and realistic emission scenarios, and a review of monitoring data.
Abstract: A comprehensive multimedia assessment of the environmental fate of bisphenol A (BPA) is presented. Components of the assessment include an evaluation of relevant partitioning and reactive properties, estimation of discharge quantities in the U.S. and the European Union (E.U.) resulting in conservative and realistic emission scenarios, and a review of monitoring data. Evaluative assessments of chemical fate using the Equilibrium Criterion (EQC) model are described from which it is concluded that the low volatility of BPA will result in negligible presence in the atmosphere. It is relatively rapidly degraded in the environment with half-lives in water and soil of about 4.5 days and less than 1 day in air, and with an overall half-life of 4.5 to 4.7 days, depending on the medium of release. The degradation rate in water is such that it may be transported some hundreds of kilometres in rivers, but long-range transport potential in air is negligible. Its low bioconcentration factor is consistent with rapid met...
190 citations
TL;DR: This review summarizes the advantages, limitations, and uncertainties of different WOE approaches, critical issues involved in selecting and executing different lines-of-evidence, and the process for subsequent characterization of the likelihood of impairment.
Abstract: It is challenging determining whether an ecosystem is impaired. The complexity of direct and indirect interactions between physical, biological and chemical components with their varying temporal and spatial scales generally renders use of multiple assessment approaches mandatory, with a consequent need to integrate different lines-of-evidence. Integration generally involves some form of weight-ofevidence (WOE). WOE approaches reported in the literature vary broadly from subjective and qualitative to quantitative. No standard approach exists and no accepted guidelines exist describing how a WOE process should be conducted. This review summarizes the advantages, limitations, and uncertainties of different WOE approaches, critical issues involved in selecting and executing different lines-ofevidence, and the process for subsequent characterization of the likelihood of impairment.
149 citations
TL;DR: The factors underlying the emergence and exchange of pathogens among marine mammals, domestic animals, and humans demand multidisciplinary study and invite regulatory and conservation scrutiny.
Abstract: A series of high profile outbreaks of newly described diseases in humans, domestic animals and wildlife has attracted widespread interest in the topic of Emerging Infectious Diseases (EIDs). Marine mammals are no exception: since 1987 several mass mortalities have been observed following infection with viruses previously undescribed in the populations or species in question. As with terrestrial examples, some of these outbreaks have followed either migrations associated with large-scale ecological changes or the introduction of virus from domestic animals. However, marine mammals warrant special concern in the context of emerging infectious diseases: they typically occupy high trophic levels and can therefore be highly contaminated with immunotoxic chemicals. Persistent Organic Pollutants (POPs), including polychlorinated -biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and related compounds, are demonstrated immunotoxicants in laboratory animals, as well as marine mammals. Immunotoxic...
142 citations
TL;DR: The overall conclusion was that based on available data, no appreciable risk to humans exists, as the detected concentrations of each of these pharmaceutical compounds found in aqueous media were far below the derived safe limits.
Abstract: Analyses were conducted on four pharmaceutical compounds, representing different therapeutic classes, to evaluate the presence and potential adverse human health effects of trace levels of these substances in aqueous environmental media. Acetylsalicylic acid, clofibrate, cyclophosphamide, and indomethacin have been detected in aqueous environmental media including sewage treatment plant effluent, surface water, drinking water, and groundwater. An extensive literature search and chemical-specific risk assessments were performed to assess the potential human health significance of each compound’s individual presence in environmental media. Safe water quality limits were estimated for each pharmaceutical by following the USEPA Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health and were compared to the concentrations found in the environment. The calculation of the provisional ambient water quality criteria involved estimation of human exposure to contaminated water, including intake via bioaccumulation in fish, and calculation of cancer risk and non-cancer hazard indices. Parameters detailing the toxicological and pharmacological nature, exposure assessment, and environmental fate and transport of each pharmaceutical were also considered. The overall conclusion was that based on available data, no appreciable risk to humans exists, as the detected concentrations of each of these pharmaceutical compounds found in aqueous media were far below the derived safe limits.
128 citations
TL;DR: In this paper, a basic framework for the ecological weight-of-evidence (WOE) process for sediment assessment is presented, which clearly defines its essential elements and will improve the certainty of conclusions about whether or not impairment exists due to sediment contamination, and, if so, which stressors and biological species (or ecological responses) are of greatest concern.
Abstract: A basic framework is presented for the ecological weight-of-evidence (WOE) process for sediment assessment that clearly defines its essential elements and will improve the certainty of conclusions about whether or not impairment exists due to sediment contamination, and, if so, which stressors and biological species (or ecological responses) are of greatest concern. The essential “Certainty Elements” are addressed in a transparent best professional judgment (BPJ) process with multiple lines-of-evidence (LOE) ultimately quantitatively integrated (but not necessarily combined into a single value). The WOE Certainty Elements include: (1) Development of a conceptual model (showing linkages of critical receptors and ecosystem quality characteristics); (2) Explanation of linkages between measurement endpoint responses (direct and indirect with associated spatial/temporal dynamics) and conceptual model components; (3) Identification of possible natural and anthropogenic stressors with associated exposure dynamic...
109 citations
TL;DR: In this article, a Monte Carlo approach was taken using simulations for 100,000 individuals representing the age, gender, and county of residence of the U.S. population based on census data.
Abstract: Arsenic is widely distributed in the environment by natural and human means. The potential for adverse health effects from inorganic arsenic depends on the level and route of exposure. To estimate potential health risks of inorganic arsenic, the apportionment of exposure among sources of inorganic arsenic is critical. In this study, daily inorganic arsenic intake of U.S. adults from food, water, and soil ingestion and from airborne particle inhalation was estimated. To account for variations in exposure across the U.S., a Monte Carlo approach was taken using simulations for 100,000 individuals representing the age, gender, and county of residence of the U.S. population based on census data. Our analysis found that food is the greatest source of inorganic arsenic intake and that drinking water is the next highest contributor. Inhalation of airborne arsenic-containing particles and ingestion of arsenic-containing soils were negligible contributors. The exposure is best represented by the ranges of inorganic...
108 citations
TL;DR: Comparing the weight of the evidence of the aquatic toxicity data that showed chronic effects at 160 μg/L and higher with typical surface water concentrations in the range of 0.001 to 0.10 μg/ L, BPA is unlikely to cause adverse effects on aquatic populations or ecosystems.
Abstract: Bisphenol A (BPA; 4,4-isopropylidene diphenol) is a chemical intermediate used primarily in the production of epoxy resins and polycarbonate products. BPA has been identified in surface waters and, hence, has been the subject of considerable research into its potential effects on aquatic organisms. Available literature on the aquatic toxicity of BPA was reviewed for quality against European Union TGD and Organization of Economic Cooperation and Development GLP principles. From this review, studies of suitable quality covering numerous ecologically relevant endpoints were identified to evaluate the survival, growth, and reproductive success of aquatic organisms exposed to BPA. Those studies yielded approximately 70 no observed effect concentrations (ranging from 16 to 3640 μg/L) and lowest observed effect concentrations (160 to 11,000 μg/L) that were considered in this weight of evidence assessment. Across all data, adverse effects on survival, growth, and reproduction occurred only at concentrations of 16...
TL;DR: The relative risk model (RRM) used in Port Valdez, AK and in Oregon's Willamette/McKenzie Watershed was applied to the Codorus Creek Watershed in south central Pennsylvania as mentioned in this paper.
Abstract: The relative risk model (RRM) used in Port Valdez, AK, and in Oregon's Willamette/McKenzie Watershed was applied to the Codorus Creek Watershed in south central Pennsylvania. The assessment evaluated the relative risk model for its applicability for ranking ecological risks within the Codorus Creek Watershed. The Codorus Creek Watershed approach included ranking stressors and habitats for regions within the watershed. Geographical Information Systems were vital in compiling and comparing stressor and habitat spatial data from regions in the watershed. The risk of ecological impacts to degrade assessment endpoints were calculated and ranked by quantitatively determining the interactions of the stressors and habitats as defined in the conceptual site model. Uncertainty assessment was conducted and the impact upon the relative ranks and risk conclusions evaluated. To determine regional risks, risk management information was gathered identifying areas to be protected, areas of high stress, and areas where add...
TL;DR: Whether PICT is a sensitive and powerful tool to quantify ecological effects in field conditions, to link them to toxicant stress, and thus to determine whether PICT may be taken into consideration in risk assessment is summarized.
Abstract: The concept of pollution-induced community tolerance (PICT) consists of the phenomenon that communities in an ecosystem exhibit increased tolerance as a result of exposure to contaminants. Although a range of ‘classic’ ecological principles explains the processes that increase tolerance of a community, the value of PICT for ecological risk assessment was recognized only recently (Blanck et al. 1988). The following issues are recognized: First, regarding the question on the role of suspect compounds causing ecological effects, the PICT approach covers the issue of causality better than ‘classical’ ecological community response parameters like species densities or species diversity indices. This relates to the fact that the level of PICT is assumed to be relatively constant (compared to density and diversity), whereas the suspect compound causing the observed effect can be deduced with relative clear inference from artificial exposure experiments. Second, PICT directly addresses a level of biological organi...
TL;DR: A rule-based, weight-of-evidence approach for assessing contaminated sediment on a site-by-site basis in the Laurentian Great Lakes is described, intended to be transparent, comprehensive, and minimally uncertain.
Abstract: A rule-based, weight-of-evidence approach for assessing contaminated sediment on a site-by-site basis in the Laurentian Great Lakes is described. Information from four lines of evidence—surficial sediment chemistry, laboratory toxicity, invertebrate community structure and invertebrate tissue biomagnification—is integrated within each line to produce a pass (‘−’) or fail (‘+’) conclusion, then combined across lines resulting in one of 16 outcome scenarios. For each scenario, the current status of the site, interpretation, and management recommendations are given. Management recommendation(s) can range from no action to risk management required (9 of the 16 scenarios). Within each line of evidence, the strength of each response can also be ranked (e.g., score of 1 to 4), providing managers with more information to aid decision options. Other issues that influence scientific management recommendations include site stability, subsurface contamination and spatial extent of effects. The decision framework is i...
TL;DR: In populations in which it has been studied, the age structure is skewed towards younger fish, and adults appear to put more energy into reproduction as a way of maintaining the population in the stressful environment.
Abstract: Mummichogs or killifish (Fundulus heteroclitus) are abundant estuarine fish that can tolerate widely varying environmental conditions. They are found in some highly contaminated sites, and their development of tolerance to toxicants has been studied. Populations have developed resistance to methylmercury, kepone, dioxins, polychlorinated biphenyls, and polyaromatic hydrocarbons. This article describes what is known about their tolerance, and discusses similarities and differences among these resistant populations. In some cases tolerance is seen only in early life stages, while in other cases tolerance is seen in adults also. In many of the populations, adults show signs of stress. The mechanism of embryo tolerance to meHg appears to be reduced chorionic permeability, and more rapid development through sensitive stages. One mechanism of resistance to dioxins, PCBs and PAHs is non-responsiveness (lack of inducibility) of CYP1A. In some populations it is already elevated, while in others it is not. Another ...
TL;DR: In this paper, the authors identify subareas inside and near an Atlantic Rain Forest reserve, the Parque Estadual Turistico do Alto Ribeira (PETAR), most likely to be affected by land use in the vicinity of the area.
Abstract: The objective of this study was to identify subareas inside and near an Atlantic Rain Forest reserve, the Parque Estadual Turistico do Alto Ribeira (PETAR), most likely to be affected by land use in the vicinity of the area. In addition, the study aimed to compare risks per stressor source (agriculture, human settlements and mining) to both epigean (surface) and hypogean (subterranean) aquatic fauna. The methodological approach included the relative vulnerability of endpoints to the stressors (pesticides, metals, nutrients, and particles) and ranking of stressor sources and habitats (epigean and hypogean streams) based on their relative distribution in 14 subareas within the catchment areas of the main rivers that cross PETAR:Piloes, Betari and Iporanga. Four subareas presented high risk for both epigean and hypogean fauna. Three of those areas were located inside the Betari catchment area, where most of the settlements andabandoned lead mines are located. The fourth area was situated in the headwaters of the Piloes River, where agricultural activities are intense. Agriculture and human settlements were the activities most likely to cause impacts on aquatic ecosystems. Uses of risk assessment results include management of the PETAR and communication to stakeholders by the Park Administration.
TL;DR: Caution is urged, therefore, in an attempt to utilize biomarkers in the risk assessment process until more complete documentation is available on the specificity, sensitivity, and time course of changes, and on the impact of multiple exposures or the time of exposures.
Abstract: Biomarkers are measurable biological parameters that change in response to xenobiotic exposure and other environmental or physiological stressors, and can be indices of toxicant exposure or effects. If the biomarkers are sufficiently specific and well characterized, they can have great utility in the risk assessment process by providing an indication of the degree of exposure of humans or animals in natural populations to a specific xenobiotic or class of xenobiotics. Most biomarkers are effective as indices of exposure, but adequate information is rarely available on the appropriate dose-response curves to have well-described biomarkers of effect that can be widely applicable to additional populations. Specific examples of acetylcholinesterase inhibition following exposure to organophosphorus insecticides are cited from experiments in both mammals (rats) and fish. These experiments have indicated that the degree of inhibition can be readily influenced by endogenous (e.g., age) and exogenous (e.g., chemical exposures) factors, and that the degree of inhibition is not readily correlated with toxicological effects. Caution is urged, therefore, in an attempt to utilize biomarkers in the risk assessment process until more complete documentation is available on the specificity, sensitivity, and time course of changes, and on the impact of multiple exposures or the time of exposures.
TL;DR: In this article, uncertainties in sediment quality assessments are discussed in five categories: (1) sediment sampling, transport and storage; (2) sediment chemistry; (3) ecotoxicology; (4) benthic community structure; and (5) data uncertainties and QA/QC.
Abstract: Uncertainties in sediment quality assessments are discussed in five categories: (1) sediment sampling, transport and storage; (2) sediment chemistry; (3) ecotoxicology; (4) benthic community structure; and (5) data uncertainties and QA/QC. Three major exposure routes are considered: whole sediments, and waters in sediment pores and at the sediment-water interface. If these uncertainties are not recognized and addressed in the assessment process, then erroneous conclusions may result. Recommendations are provided for addressing the identified uncertainties in each of the key areas. The purpose of this paper is to improve the reporting of sediment quality assessments.
TL;DR: The biomarker approach, adopted from medical toxicology, is subject to several theoretical and practical difficulties when used to address environmental problems and an empirical weight of evidence approach to improve the utility of sentinel species is proposed.
Abstract: The biomarker approach, adopted from medical toxicology, is subject to several theoretical and practical difficulties when used to address environmental problems. The problems are related to the definition that emphasizes measurement but does not specify a requirement to establish cause-effect linkages. An improved definition for a bioindicator is reviewed. The sentinel species approach is judged to be a biomarker rather than a bioindicator, and therefore of limited use for environmental risk assessment. An empirical weight of evidence approach to improve the utility of sentinel species is proposed.
TL;DR: In this paper, a comprehensive study of the potential human health risks associated with the environmental applications (e.g., fill, roadbase, landscaping) of iron-and steel-making slag was performed using characterization data for 73 samples of slag collected from blast furnaces, basic oxygen furnaces and electric arc furnaces.
Abstract: Steel-industry slag, a co-product of iron and steel production, is produced and sold for use in a wide range of applications. A comprehensive study of the potential human health risks associated with the environmental applications (e.g., fill, roadbase, landscaping) of iron- and steel-making slag was performed using characterization data for 73 samples of slag collected from blast furnaces, basic oxygen furnaces, and electric arc furnaces. Characterization data were compared to regulatory health-based “screening” benchmarks to determine constituents of interest. Antimony, beryllium, cadmium, trivalent and hexavalent chromium, manganese, thallium, and vanadium were measured above screening levels and were assessed in an application-specific exposure assessment using standard U.S. Environmental Protection Agency risk assessment methods. A stochastic analysis was conducted to evaluate the variability and uncertainty in the inhalation exposure and risk estimates, and the oral bioaccessibility of certain metal...
TL;DR: In this article, the authors used a second-order two-dimensional Monte Carlo analysis and probability bounds analysis to investigate the impact of variability and uncertainty on the results of a food-web exposure model.
Abstract: The results of quantitative risk assessments are key factors in a risk manager's decision of the necessity to implement actions to reduce risk. The extent of the uncertainty in the assessment will play a large part in the degree of confidence a risk manager has in the reported significance and probability of a given risk. The two main sources of uncertainty in such risk assessments are variability and incertitude. In this paper we use two methods, a second-order two-dimensional Monte Carlo analysis and probability bounds analysis, to investigate the impact of both types of uncertainty on the results of a food-web exposure model. We demonstrate how the full extent of uncertainty in a risk estimate can be fully portrayed in a way that is useful to risk managers. We show that probability bounds analysis is a useful tool for identifying the parameters that contribute the most to uncertainty in a risk estimate and how it can be used to complement established practices in risk assessment. We conclude by promoti...
TL;DR: In this article, the authors present an approach to the combination of multiple lines of evidence through calculation of weight-of-evidence, with reference conditions used to define a not impaired state.
Abstract: Environmental decision-making is con~plex and often based on multiple lines of evidence. Integrating the infornlation from these multiple lines of evidence is rarely asinlplc process. We present aquantitative approach to the combination of multiple lines of evidence through calculation of weight-of-evidence, with reference conditions used to define a not impaired state. The approach is risk-based with measure. . ment of risk computed as the probability of impairment. When data on reference conditions are available, there are a variety of methods for calculating this probabilitv. Statistical theorv and the use of odds ratios orovide a method for combinine the '2 measures of risk from the different lines of evidence. The approach is illustrated using data from the Great Lakes to predict the risk at potentially contaminated sites.
TL;DR: No consensus on the design of a framework is apparent and work remains to be done on refining an integrative framework that effectively incorporates both policy and science considerations for environmental management purposes.
Abstract: Ecological risk assessment and management have grown from a long history of assessment and management activities aimed at improving the everyday lives of humans. The background against which ecological risk assessment and management has developed is discussed and recent trends in the development of risk assessment and management frameworks documented. Seven frameworks from five different countries are examined. All maintain an important role for science, suggest adaptive approaches to decision-making and have well-defined analytical steps. Differences in approaches toward the separation of policy and science, the preference for management over assessment, the inclusion of stakeholders, the iterative nature of the analytical cycle, the use of decision criteria and economic information suggest considerable evolution in framework design over time. Despite the changes, no consensus on the design of a framework is apparent and work remains to be done on refining an integrative framework that effectively incorp...
TL;DR: In this paper, a modified potential ammonium oxidation assay was used to determine the metal tolerance of the AOB community in a soil contaminated with copper, chromium, and arsenic.
Abstract: This study attempted to investigate if the tolerance of soil bacterial communities in general, and autotrophic ammonia-oxidizing bacteria (AOB) in particular, evolved as a result of prolonged exposure to metals, and could be used as an indigenous bioindicator for soil metal pollution. A soil contaminated with copper, chromium, and arsenic (CCA) was mixed with an uncontaminated garden soil (GS3) to make five test soils with different metal concentrations. A modified potential ammonium oxidation assay was used to determine the metal tolerance of the AOB community. Tolerance to Cr, Cu, and As was tested at the beginning and after up to 13 months of incubation. Compared with the reference GS3 soil, the five CCA soils showed significantly higher tolerance to Cr no matter which form of Cr (Cr3+, CrO4 2−, or Cr2O7 2−) was tested, and the Cr tolerance correlated with the total soil Cr concentration. However, the tolerance to Cu2+, As3+, and As5+ did not differ significantly between the GS3 soil and the five CCA s...
TL;DR: The Scoring and Ranking Assessment Model (SCRAM) as discussed by the authors was developed to serve as an analytical tool in chemical scoring and ranking of Great Lakes contaminants and provides an initial screening of contaminants.
Abstract: The Scoring and Ranking Assessment Model (SCRAM) was developed to serve as an analytical tool in chemical scoring and ranking of Great Lakes contaminants. The model provides an initial screening ev...
TL;DR: Based on human health epidemiological criteria, an approach is developed that moves from systematic consideration of seven basic questions to assigning a likelihood of involvement of putative agents.
Abstract: Retrospective ecological risk assessment attempts to identify likely causal agents to explain adverse effects that have occurred in ecological targets. It can never be decisive since it is post hoc and usually based on limited evidence that is rarely very quantitative. It can, nevertheless, be made more transparent, systematic, and logical, and less subjective. Based on human health epidemiological criteria we develop an approach that moves from systematic consideration of seven basic questions to assigning a likelihood of involvement of putative agents. The questions are: 1. Is there evidence that the target is or has been exposed to the agent? 2. Is there evidence for correlation between adverse effects in the target and exposure to the agent either in time or in space? 3. Do the measured or predicted environmental concentrations exceed quality criteria for water, sediment or body burden? 4. Have the results from controlled experiments in the field or laboratory led to the same effect? 5. Has removal of...
TL;DR: Contaminants such as PAHs and PCBs are demonstrated to influence salmon health, and thus have the potential to adversely impact salmon populations.
Abstract: Wild Pacific salmon populations are in serious decline, and as a result, a number of salmon stocks are listed as threatened or endangered under the Endangered Species Act. Our research identifies and supports the possibility that certain environmental contaminants can alter salmon survival, and as a result may contribute to these species being at risk. We have shown that juvenile chinook salmon (Oncorhynchus tshawytscha) are exposed to polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) as they migrate through a contaminated urban estuary in Puget Sound WA (the Duwamish Waterway estuary). Immune function was analyzed in these fish by examining the ability of their anterior kidney and splenic leukocytes to produce a primary and secondary in vitro plaque-forming cell (PFC) response to the hapten, trinitrophenyl (TNP), and by determining their susceptibility to a marine pathogen, Vibrio anguillarum. We found that fish outmigrating from the urban estuary produced a significantly lower...
TL;DR: These findings are consistent with epidemiological data suggesting an inverse relationship between background radiation and cancer incidence and with occupational epidemiological investigations in which low-dose exposure groups display markedly lower standardized mortality rates than the referent or control group.
Abstract: Despite the long history of radiation hormesis and the public health concerns with low-level exposures to ionizing radiation, there has been surprisingly little formal evaluation of whether hormetic effects are displayed with respect to radiation exposure and cancer incidence (i.e., reduced cancer risk at low radiation doses compared to controls, enhanced cancer risk at higher doses) until relatively recently. This paper reviews data relevant to the question of radiation hormesis and cancer with particular emphasis on experimental studies in animal models exposed to low levels of ionizing radiation. Data exist that provide evidence both consistent with and/or supportive of radiation hormesis. Other biomedical research provides potentially important mechanistic insight: low dose exposures have the capacity to activate immune function to prevent the occurrence of tumor development and metastasis; low doses of radiation have been shown to reduce mutagenic responses and induce endogenous antioxidant responses...
TL;DR: In this paper, a detailed look at the occurrence of genetic adaptations and ecological impacts at three contaminated sites (Foundry Cove, Bayou Trepagnier, Pass Fourchon) is presented.
Abstract: This paper takes a detailed look at the occurrence of genetic adaptations and ecological impacts at three contaminated sites (Foundry Cove, Bayou Trepagnier, Pass Fourchon) to assess the co-occurrence of adaptation and ecological impacts and the implications for risk assessment. Community-level ecological impacts were reported for all three sites. However, there was little evidence of population-level impacts (on the six populations that were also assessed for adaptation). Similarly, adaptation was found in only one of the populations. While this review provides an incomplete picture (adaptation was assessed on only a small subset of the species present and the reasons behind the lack of adaptation in the five populations remained unknown), it indicates that adaptation is uncommon even where ecological impacts are obvious. Theoretical considerations also predict that contaminants can have large impacts without resulting in an adaptation. While adaptation to a contaminant reflects an impact by that contami...
TL;DR: In this paper, a simple simulation model is presented to illustrate the effects of spatial heterogeneity by linking an individual-based toxicokinetic model with landscape ecology for risk assessment of toxic substances.
Abstract: Traditional approaches to ecotoxicology and ecological risk assessment frequently have ignored the complexities arising due to the spatial heterogeneity of natural systems. In recent years, however, ecologists have become increasingly aware of the influence of spatial organization on ecological processes. Landscape ecology provides a conceptual and theoretical framework for the analysis of spatial patterns, the characterization of spatial aspects of ecosystem function, and the understanding of landscape dynamics. Incorporating the insights of landscape ecology into ecotoxicology will enhance our ability to understand and ultimately predict the effects of toxic substances in ecological systems. Ecological risk assessments need to explicitly consider multiple spatial scales, accounting for heterogeneity within contaminated areas and for the larger landscape context. A simple simulation model is presented to illustrate the effects of spatial heterogeneity by linking an individual-based toxicokinetic model wi...