Wayne G. Landis

Environmental toxicology and risk assessment

This symposium was held April 14--16, 1991 in Atlantic City, New Jersey. The purpose of this conference was to provide a forum for exchange of state-of-the-art information on environmental toxicology. A major theme in this volume is on ecological risk assessment. Topics focus on the following: ecological risk assessment under TSCA; evaluating ecological impacts at the population and community levels; biomarkers; marine toxicity and test methods; and methods development. Individual papers have been processed separately for inclusion in the appropriate data bases.

Well past time to stop using NOELs and LOELs

The problem with NOELs and LOELs is basic. The fundamental model of environmental toxicology is the exposure–response (or concentration–response or dose– response) curve that describes the relationship between exposure and effect. It is a given that the best possible description of this relationship must be the keystone of the field of toxicology. NOEL and LOELs do not meet the criterion of adequately describing the exposure–response curve. Exposure-Response It’s the curve!

Regional Scale Ecological Risk Assessment : Using the Relative Risk Model

As debates over how relative risk can be used to shape landscape-scale environmental management intensify, Regional-Scale Risk Assessment demonstrates the capabilities of RRM using nine case studies in the Pacific Northwest, Pennsylvania, Brazil, and Tasmania. The authors use a process of ranking and filters to interrelate different kinds of risks and illustrates how these relative risks are defined, mapped, and analyzed to determine remediation and management priorities. This book provides detailed descriptions for each step of RRM-from the determination of assessment goals to documentation, evaluation, and communication with decision-makers-that can benefit practitioners in environmental risk assessment and related fields worldwide.

A Regional Multiple-Stressor Rank-Based Ecological Risk Assessment for the Fjord of Port Valdez, Alaska

We conducted an ecological risk assessment of the marine environment of Port Valdez, a fjord in south-central Alaska. Because the assessment was regional rather than site-specific and contained a large number of different stressors in a variety of environments, we required a nontraditional method to estimate risks. We created a Relative Risk Model to rank and sum individual risks numerically within each subarea, from each source, and to each habitat. Application of this model involved division of Port Valdez into 11 subareas containing specific ecological and anthropogenic structures and activities. Within each subarea, the stressor sources were analyzed to estimate exposure of receptors within habitats leading to effects relevant to the chosen assessment endpoints. The subareas were analyzed and compared to form a Port-wide perspective of ecological risk. Available chemical concentrations from sediment and mussels collected from the Port were compared to various toxicological benchmarks as a partial conf...

Regional Ecological Risk Assessment of a Near Shore Marine Environment: Cherry Point, WA

ABSTRACT We conducted a regional ecological risk assessment for a near shore marine environment in northwestern Washington State using the Relative Risk Model. The objectives of this study were threefold: (1) to analyze cumulative impacts from multiple sources of chemical and non-chemical stressors in the near shore region and upland watersheds of Cherry Point (2) to determine the utility of Monte Carlo type uncertainty analysis in a rank-based regional risk assessment and (3) to investigate the effects of model habitat characterization on risk estimates. We used geographic information systems to compile and compare spatial data to determine ranks for sub-regions within the study area. By quantitatively combining ranks with exposure and effects filters, we estimated total relative risk between sub-regions and relative contributions of stressors. Finally, we used Monte Carlo analysis and an alternative ranking scheme to evaluate the effects of model and parameter uncertainty on risk predictions. The regional risk assessment results suggest the major contributors of risk are vessel traffic, upland urban and agricultural land use and shoreline recreational activities. This assessment demonstrated the applicability of regional risk assessment to marine near shore regions and the benefit of Monte Carlo analysis in describing uncertainty in a Relative Risk Model regional risk assessment.

A Regional Multiple Stressor Risk Assessment of the Codorus Creek Watershed Applying the Relative Risk Model

The relative risk model (RRM) used in Port Valdez, AK, and in Oregons 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 additional information is needed. The results supported the applicability of the RRM and suggested areas and stressors for restoration efforts in the Codorus Creek Watershed. Two critical sets of conclusions were drawn from the assessment. First, in the Codorus Creek Watershed, the most significant stressor is agriculture land use, the most significantly impacted endpoint is water quality, and the most vulnerable habitats are those for macroinvertebrates and warm-water fish. Second, this risk assessment demonstrates the feasibility of using the RRM for assessing risk from multiple stressors on habitats with multiple assessment endpoints in an eastern watershed.

Developing a regional ecological risk assessment: a case study of a Tasmanian agricultural catchment.

A regional ecological risk assessment was conducted for the Mountain River catchment in Tasmania, Australia. The Relative Risk Model was used in conjunction with geographic information systems interpretations. Stakeholder values were used to develop assessment endpoints, and regional stressors and habitats were identified. The risk hypotheses expressed in the conceptual model were that agriculture and land clearing for rural residential are producing multiple stressors that have potential for contamination of local waterbodies, eutrophication, changes in hydrology, reduction in the habitat of native flora and fauna, reductions in populations of beneficial insects in agricultural production systems, increased weed competition in pastures, and loss of aesthetic value in residential areas. In the risk analysis the catchment was divided into risk regions based on topography and land use. Stressors were ranked on likelihood of occurrence, while habitats were ranked on percentage land area. Risk characterization showed risks to the maintenance of productive primary industries were highest across all risk regions, followed by maintenance of a good residential environment and maintenance of fish populations. Sensitivity analysis was conducted to show the variability in risk outcomes stemming from uncertainty about stressors and habitats. Outcomes from this assessment provide a basis for planning regional environmental monitoring programs.

Regional Risk Assessment of a Brazilian Rain Forest Reserve

The objective of this study was to identify subareas inside and near an Atlantic Rain Forest reserve, the Parque Estadual Turístico 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: Pilões, 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 and abandoned lead mines are located. The fourth area was situated in the headwaters of the Pilões 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.

ECOLOGICAL RISK ASSESSMENT IN THE CONTEXT OF GLOBAL CLIMATE CHANGE

Changes to sources, stressors, habitats, and geographic ranges; toxicological effects; end points; and uncertainty estimation require significant changes in the implementation of ecological risk assessment (ERA). Because of the lack of analog systems and circumstances in historically studied sites, there is a likelihood of type III error. As a first step, the authors propose a decision key to aid managers and risk assessors in determining when and to what extent climate change should be incorporated. Next, when global climate change is an important factor, the authors recommend seven critical changes to ERA. First, develop conceptual cause–effect diagrams that consider relevant management decisions as well as appropriate spatial and temporal scales to include both direct and indirect effects of climate change and the stressor of management interest. Second, develop assessment end points that are expressed as ecosystem services. Third, evaluate multiple stressors and nonlinear responses—include the chemicals and the stressors related to climate change. Fourth, estimate how climate change will affect or modify management options as the impacts become manifest. Fifth, consider the direction and rate of change relative to management objectives, recognizing that both positive and negative outcomes can occur. Sixth, determine the major drivers of uncertainty, estimating and bounding stochastic uncertainty spatially, temporally, and progressively. Seventh, plan for adaptive management to account for changing environmental conditions and consequent changes to ecosystem services. Good communication is essential for making risk-related information understandable and useful for managers and stakeholders to implement a successful risk-assessment and decision-making process. Environ. Toxicol. Chem. 2013;32:79–92.

Conceptual Model Development for Invasive Species and a Regional Risk Assessment Case Study: The European Green Crab, Carcinus maenas, at Cherry Point, Washington, USA

Abstract The goal of this article was to generate a method of regional scale ecological risk assessment using an adaptation Relative Risk Model (RRM). As a case study we performed a quantitative, regional risk assessment of an invasive species, the European green crab (Carcinus maenas) at Cherry Point, Washington, USA. The conceptual model was modified from the RRM and incorporates the structure of the hierarchical patch dynamic paradigm. The ranks and filters were integrated to determine the relative contribution of each source of C. maenas to risk as well as the risk to selected biological endpoints, habitats and sub-regions for two source scenarios: (1) current conditions (2004) and (2) future conditions during an El Nino year. The results suggest that the habitat and endpoint with the greatest risk are the eelgrass habitat and the juvenile Dungeness crab, respectively. The Cherry Point subregion was identified as the area having the most risk in the first source scenario, while the Lummi Bay sub-region is most at risk during an El Nino event. The risk of impacts is substantially higher for all endpoints, habitats and sub-regions when El Nino–driven current dispersal is considered. The methodology applied in this case study can be modified and applied to determine the risk of introduction and impacts of other invasive species to the Strait of Georgia, Puget Sound, and other coastal areas.