Steven M Bartell

• PhD
• Senior Principal - Ecological and Environmental Modeling at Cardno

This study explores causal mechanisms of river metamorphosis and its impacts on regional landscapes. The study also investigates the implications of metamorphosis on associated ecological resources. Advanced GIS and remote sensing technologies were used to delineate morphological parameters describing metamorphosis of the Old Brahmaputra River from...

Introduction Habitat restoration aims at reinstating abiotic and biotic habitat conditions to support long-term species persistence and viability. This management practice is commonly part of recovery plans developed for species listed as threatened or endangered under the Endangered Species Act. The endangered Topeka shiner (Notropis topeka) inhab...

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment. Unlike other persistent chemicals, PFAS are highly soluble in water and tend to partition to surface and groundwater rather than soil and sediment. While numerous studies have evaluated the potential ecological effects of certain PFAS, there remain data gaps, especially f...

The occurrence of some species listed under the Endangered Species Act in agricultural landscapes suggests that their habitats could potentially be exposed to pesticides. However, the potential effects from such exposures on populations are difficult to estimate. Mechanistic models can provide an avenue to estimating the potential impacts on popula...

Draft discussion concerning the development and implementation of a biophysical-based economy with an emphasis on human carrying capacity.

The comprehensive aquatic systems model (CASM), an aquatic food web – ecosystem model, was developed originally to explore relationships between food web structure and ecosystem function, then subsequently adapted to assess potential ecological risks posed by chemical contaminants. This short communication presents the history of the CASM, describe...

Levee setbacks are defined by the intentional relocation of levees away from the river bank. This placement is often done to reduce flood risk, but it can also have environmental benefits. The Comprehensive Aquatic System Model (CASM) was used to look at the potential fate of nutrients and several environmental benefits for five potential managemen...

Delta smelt struggle to persist in a dramatically altered estuarine environment. Complex and incompletely understood relationships between food availability, environmental stressors, other components of the species’ habitat, and the abundance of delta smelt impede the effective management and recovery of the species. The empirical modeling presente...

The Topeka shiner, a small cyprinid fish, is a seminal example of an endangered aquatic species in the Midwestern USA. Populations and their associated critical habitats may experience potential direct and/or indirect effects from anthropogenic activity. However, potential impacts on fish populations from alterations in the food web are difficult t...

A hybrid model characterized potential ecological risks posed by atrazine to the endangered Topeka shiner. The model linked an individual-based bioenergetics population model (TS-IBM) to a Comprehensive Aquatic System Model (CASMTS ) to simulate Topeka shiner population and food web dynamics for an Iowa headwater pool. Risks were estimated for moni...

Potential toxic effects of thiamethoxam (TMX) on non-target organisms and community structure of a generic Midwestern farm pond and emergent wetland were assessed using two versions of the Comprehensive Aquatic System Model, the CASMGFP – a generic farm pond model, and the CASMGWL – a generic wetland model. The CASMGFP and CASMGWL are integrated bi...

Toxic chemicals can exert effects on all levels of the biological hierarchy, from cells to organs to organisms to populations to entire ecosystems. However, most risk assessment models express their results in terms of effects on individual organisms, without corresponding information on how populations, groups of species, or whole ecosystems may r...

"The purpose of this project was to develop a methodology for deriving site-specific" nutrient criteria (SSNC) for surface waters, including streams and rivers, lakes and reservoirs, and coastal estuaries. The methodology was developed to extend the specification of United States Environmental Protection Agency regional nutrient criteria for more l...

Potential effects of atrazine on the non-target aquatic plants characteristic of lower-order Midwestern streams were previously assessed using the Comprehensive Aquatic System Model (CASMATZ ). Another similar bioenergetics-based, mechanistic model, AQUATOX, was examined in this study with the objectives of (a) developing an AQUATOX model simulatio...

Relieving phosphorus loading is a key management tool for controlling Lake Erie eutrophication. During the 1960s and 1970s, increased phosphorus inputs degraded water quality and reduced central basin hypolimnetic oxygen levels which, in turn, eliminated thermal habitat vital to cold-water organisms and contributed to the extirpation of important b...

The comprehensive aquatic systems model for atrazine (CASMATZ ) estimates the potential toxic effects of atrazine on populations of aquatic plants and consumers in a generic lower-order midwestern stream. The CASMATZ simulates the daily production of 20 periphyton and 6 aquatic vascular plant species. The modeled consumer community consists of 17 f...

With the advent of improved analytical detection capabilities, a variety of organic chemicals have been found in trace amounts (Trace Organic Chemicals, TOrCs) in surface waters, sediment, and fish tissue. These TOrCs include pharmaceuticals, personal care products, surfactants, and other currently unregulated chemicals. This WERF sponsored researc...

Ecological risks and economical impacts of zebra mussels (Dreissena polymorpha) include alterations in the transfer of energy and cycling of materials in aquatic systems, increased accumulation of contaminants in aquatic food chains, clogging of water intakes, and damage to related infrastructure. A risk-based decision model was developed to assess...

The widespread loss of oak-hickory forests and the impacts of flood have been major issues of ecological interest concerning forest succession in the Upper Mississippi River (UMR) floodplain. The data analysis from two comprehensive field surveys indicated that Quercus was one of the dominant genera in the UMR floodplain ecosystem prior to the 1993...

A Markov-chain transition model (FORSUM) and Monte Carlo simulations were used to simulate the succession patterns and predict a long-term impact of flood on the forest structure and growth in the floodplain of the Upper Mississippi River and Illinois River. Model variables, probabilities, functions, and parameters were derived from the analysis of...

This chapter describes methods for assessing the movement of radionuclides along pathways of transport and bioaccumulation in rivers, reservoirs, lakes, estuaries, and coastal oceans. The materials presented here focus primarily on the accumulation of radionuclides by aquatic organisms. The key pathways for transport and bioaccumulation are demonst...

A series of locks and dams were constructed and put into operation on the Upper Mississippi River in the 1930s to facilitate commercial navigation. As a result, historical floodplain landscapes were altered. For example, islands characterized by floodplain forests experienced prolonged unfavourable hydrologic conditions and were eliminated from man...

Cellular and subcellular measures of exposure (biomarkers) and effects (bioindicators) continue to be developed. This development is justified in part by the potential application of these technologies in supporting ecological risk assessment (ERA). However, application of biomarkers in assessing ecological risk remains infrequent and of questionab...

A biocide decay model was developed to assess the potential efficacy and environmental impacts associated with using glutaraldehyde to treat unballasted overseas vessels trading on the Laurentian Great Lakes. The results of Monte Carlo simulations indicate that effective glutaraldehyde concentrations can be maintained for the duration of a vessel's...

This article presents a quantitative methodology for evaluating the probability of invasive pest species establishing persistent populations. The estimation of pest establishment relies on data and information describing the biology and ecology of the pest and its interactions with potential host species and the regional environment. This informati...

We used a Lake Suwa version of Comprehensive Aquatic Systems Model (CASM_SUWA) to demonstrate the risk estimation of 10 different chemicals and examined the applicability and reliability of the model in ecological risk assessment by qualitatively and quantitatively comparing with the results of studies on multiple species using mesocosm tests. The...

Ecological models are useful tools for evaluating the ecological significance of observed or predicted effects of toxic chemicals on individual organisms. Current risk estimation approaches using hazard quotients for individual-level endpoints have limited utility for assessing risks at the population, ecosystem, and landscape levels, which are the...

Ecological models have been developed and used in management of renewable natural resources, conservation biology, and assessments of ecological risks posed by toxic chemicals and other stressors. Because few models have been developed specifically for use in assessing chemical risks, this study examines the realism and relevance of a wide range of...

The continued urbanization of coastal watersheds can influence the quality of water that enters rivers and estuaries. Intelligent management of aquatic resources will require the capability to quantitatively assess and evaluate the impacts of alterations in surface waters that result from changes in patterns of land use. An aquatic ecosystem model...

The US Department of Energy (USDOE) facilities encompass large tracts of land that include important regional ecological resources. The historical development and continued operation of these facilities has changed the structure of regional landscapes. A quantitative analysis was performed to determine if patterns of land use within the boundaries...

The Lake Suwa version of the comprehensive aquatic systems model (CASM-SUWA) was developed using field data from Lake Suwa and evaluated to examine the utility of CASM-SUWA for assessing the ecological risk of chemicals for aquatic ecosystems. The calibration of the parameters for the model provided that the established reference model simulation c...

Ecological risks are inherently spatial, and the consideration of scale is critical to all aspects of the ecological risk assessment process. Analysis of alterations in land use and habitat quality and quantity in relation to historical, continuing, and future US Department of Energy (USDOE) operations may be as important as assessing impacts resul...

Historical and continuing US Department of Energy (USDOE) operations have not only contaminated the environment but have altered the landscape as well as habitat quality and quantity. The changes in the landscape that have occurred within USDOE facilities may be as important as assessing the effects resulting from the release of chemical contaminan...

The U.S. Environmental Protection Agency (U.S. EPA) has developed guidance on regional nutrient criteria for lakes and reservoirs, rivers and streams, and estuaries. This WERF project (Project 99-WSM-3) has developed methods, procedures, and guidance for setting site-specific nutrient criteria for these types of water bodies. Site-specific means th...

The underwater light climate is one of the most important determinants of submersed aquatic vegetation. Because of the recent, large-scale, declines in aquatic vegetation, largely attributed to deterioration of the underwater light climate, interest in tools to predict the wax and wane of aquatic macrophyte populations has greatly increased. This p...

The purpose of this study was to add to the set of risk characterization approaches developed in an earlier study beyond simple comparisons of exposure and effects (e.g., quotients, overlapping frequency distributions) through use of ecological models. These models were used to evaluate the ecological risks from diquat dibromide for individual Daph...

The purpose of this study was to add to the set of risk characterization approaches developed in an earlier study beyond simple comparisons of exposure and effects (e.g., quotients, overlapping frequency distributions) through use of ecological models. These models were used to evaluate the ecological risks from diquat dibromide for individual Daph...

The phenomenon of hormesis has been observed mainly for the response of individual organisms to stress. A reasonable line of inquiry might explore the possibility of observing hormesis at other levels of ecological organization. This initial examination focuses on ecosystem hormesis. Explorations of hormetic responses of ecosystems to stress cannot...

Realistic and reliable methods are needed for the accurate characterization of the potential ecological risks posed by pesticides. This study presents a sequence of risk assessment methods that are based on the comparison of exposure concentrations to laboratory-derived toxicity data for representative species of aquatic organisms exposed to pestic...

Realistic and reliable methods are needed for the accurate characterization of the potential ecological risks posed by pesticides. This study presents a sequence of risk assessment methods that are based on the comparison of exposure concentrations to laboratory-derived toxicity data for representative species of aquatic organisms exposed to pestic...

In order to apply ecological models to ecological risk assessment, it is important to understand the strength and limitation of the model and to determine the domain of the model applicability in ecological risk assessment. The study presented here used the Lake Suwa version of Comprehensive Aquatic Systems Model (CASM_SUWA) to demonstrate risk est...

The comprehensive aquatic systems model (CASM) was adapted for estimating ecological risks posed by toxic chemicals in rivers, lakes, and reservoirs in Québec, Canada. Populations of aquatic plants, invertebrates, and fish characteristic of these aquatic ecosystems were identified and generic food webs were constructed. Bioenergetics parameters tha...

Traditionally, regulatory approaches to the bioaccumulation of hydrophobic organic chemicals (HOCs) have emphasized the direct accumulation of these chemicals from solution across biological membranes, leading to the development of the bioconcentration factor as a measure of direct uptake of freely dissolved HOCs. However, an often larger fraction...

Ecological risk assessment will continue to increase in importance as a conceptual and methodological basis for evaluating environmental impacts as required by the National Environmental Policy Act. Understanding the historical strengths and limitations of more traditional environmental assessments performed in support of the NEPA can facilitate th...

The uncertainties in the exposure predictions after contamination of an urban area due to the variabilities in environmental transfer parameters and in dose conversion factors have been estimated. This was done using the "Latin Hypercube" sampling scheme and the computer codes PRISM and PARATI. For the scenario 'urban contamination by 137Cs' and th...

The main purpose of this paper is to explore potential relationships between ecological risk assessment and ecosystem valuation. The relationships may already be more than potential. For example, ecological risk assessments invariably provide information used in decision making, certainly in the environmental regulatory arena (e.g., RCRA/CERCLA, or...

The purpose of this study was to investigate the implication of adding hydrodynamic complexity in estimating the exposure of biota to ¹³⁷Cs in the Chernobyl cooling pond (lake) from May to September 1986. Hydrodynamics was incorporated into this study in two ways. First, the radionuclide transport and distributions were estimated by using a hyd...

Ecological risk assessment (ERA) continues to evolve as an effective conceptual and methodological framework for estimating and evaluating the probable environmental impacts of industrial chemicals (Goldstein and Ricci, 1981; Bartell et al., 1984, 1992; Bartell, 1990a,b; Suter, 1992; USEPA, 1992; Calabrese and Baldwin, 1993; Parkhurst, 1993; Pascoe...

This report presents guidelines for evaluating uncertainty in mathematical equations and computer models applied to assess human health and environmental risk. Uncertainty analyses involve the propagation of uncertainty in model parameters and model structure to obtain confidence statements for the estimate of risk and identify the model components...

Sumario: Background and motivation for ecological risk analysis -- Toxicological and ecological data for risk analysis -- An aquatic ecosystem model for risk analysis -- Modeling sublethal toxic effects -- Forecasting risk in aquatic ecosystems -- Evaluation of the risk forecasting methodology -- Comparisons of predicted and measured effects -- Con...

The purpose of this work was to examine possible implications of parameter uncertainties on the estimates of population exposure to 137Cs following the Goiania (Brazil) accident. The relevance of these uncertainties in decision making at the time of the accident and in outlining future research aimed at reducing the critical uncertainties was exami...

Complex models are often used to make predictions of environmental effects over a broad range of temporal and spatial scales. The data necessary to adequately estimate the parameters of these complex models are often not available. Monte Carlo filtering, the process of rejecting sets of mode! simulations that fail to meet prespecified criteria of m...

Methods are described for extrapolating acute toxicity data to expected effects of toxic substances on fish populations in pelagic ecosystems. The methods are based on a physiological process equation for fish growth; the equation was modified to express sublethal toxic effects. The methods are exemplified by an estimation of the risks posed to fis...

The purpose of this chapter is to use the Regional Acidification INformation and Simulation (RAINS) model and data from Fennoscandia lakes: identify and quantify errors associated with extrapolation of site-specific information; test and quantify our abilities to perform useful extrapolations; and establish guidelines and limits for the role of dat...

The attempt to explain the observed structure of ecological food webs has been one of the recent key issues of theoretical ecology. Unquestionably, many factors are involved in determining food-web structure. The dissipation of available energy from one trophic level to the next has been emphasized by Yodzis as the major factor limiting the length...

The objectives of regulatory practice have evolved from eliminating all risks of pesticides and toxic chemicals to the environment to reducing risks to acceptable levels. This change in philosophy requires the development of methods for quantifying the risks of toxicant exposure to the exposed biota. Ecological risk assessment models that are compa...

A model that simulated the daily production of 100 theoretical algal populations was used to define a sampling universe for the construction and evaluation of aggregated models of phytoplankton community structure. Three model communities consisting of ten populations each were constructed by aggregating parameters from subsets of the original 100...

The state of an ecosystem at any time t may be characterized by a multidimensional state vector x(t). Changes in state are represented by the trajectory traced out by x(t) over time. The effects of toxicant stress are summarized by the displacement of a perturbed state vector, x/sub p/(t), relative to an appropriate control, x/sub c/(t). Within a m...

A model was previously developed to examine the implications of size-dependent growth and feeding relationships among phytoplankton and zooplankton on phytoplankton productivity. For each zooplankton population size the model defined a corresponding average individual weight that associated with maximum algal productivity. The algal productivities...

In retrospect, what we now call complex interactions encompass several of the major advances in aquatic ecology. Some examples include the trophic-dynamic concept (Lindeman 1942), the multidimensional niche (Hutchinson 1957), size selective predation and the size efficiency hypothesis (Hrbacek et al. 1961; Hrbacek 1962; Brooks and Dodson 1965), the...

The scales employed in investigations of aquatic ecosystems can strongly influence interpretations of community patterns and processes. Some examples are obvious; in contrasting cladocerans and rotifers, assessments of biomass (an instantaneous time scale) provide strikingly different impressions than assessments of production (a broader time scale...

Factors associated with differences in biological productivity between lakes can result in significant differences in the predictions and uncertainties of radium in various aquatic components. -from Authors

Description The 10th volume in this series begins with a review of aquatic toxicology from its early dealing with acute problems, to its current statue as a mature field of science capable of dealing with long-term and sophisticated issues. The volume also features papers in two sections that address new aspects of aquatic toxicology: 1) bioenginee...

Description Fifteen peer-reviewed papers emphasize the use of biological function couple with biological structure information to predict the effects of anthropogenic stress on aquatic communities and ecosystems.

Current ecological thinking offers two alternative explanations of measured structure in phytoplankton assemblages. First, interest has been rekindled in the ability of competition theory (Slobodkin 1961; MacArthur 1969; May 1975) to explain patterns of species replacement in phytoplankton (Dugdale 1967; Tilman 1977; Tilman et al. 1981). Competitio...

Predictions from the RAINS Lake Module (RLM) and data from Finno-Scandia are compared to identify and quantify errors associated with extrapolation of site-specific information; test and quantify our abilities to perform useful extrapolations; and establish guidelines and limits for the role of data and models in regional assessments. The results s...

A dynamic model of radium transfers between water, sediments and fish-flesh was developed to compare lakes that differ in their biological and physical characteristics. Results indicate that factors associated with differences in biological productivity between lakes can result in significant differences in the predictions and uncertainties of radi...

An integrated fates and effects model was derived to simulate the toxic effects of naphthalene exposure on the growth of auatic populations. Effects on production were calculated on the basis of dose-response functions specific to each population in relation to changing concentrations of accumulated naphthalene. Separate simulations using constant...

Methods are described for comparing distributions of model predictions with data that make explicit the contributions of bias and variance. The methods were used to evaluate dose-response models developed to forecast the toxic effects of phenolic compounds on algal photosynthesis and abundance of Daphnia measured in pond experiments. Variances of m...

We quantified the sensitivity of predicted rates of growth and consumption to parameter variation for models of yellow perch (Perca flavescens), largemouth bass (Micropterus salmoides), and alewife (Alosa pseudoharengus). We used statistical analyses of the results of Monte Carlo simulations to rank parameter importance. The order of parameter impo...

Assessments of ecological risks associated with toxic contaminant releases necessarily involve extrapolation from observed responses of simplified laboratory systems to predicted responses of complex natural systems. In this paper we evaluate the utility of population and ecosystem theory for making these extrapolations, based on: (1) the success o...

Prior to the late 1970s, little attention was given to the investigation of the environmental behaviour and fate of 99Tc. Environmental assessments of the radiological impact of technetium releases were based on the predictions of mathematical models that, in the absence of data on technetium, contained parameter values that were based on a series...

Ecosystem experiments were undertaken to investigate the long-term fate and effects of coal liquefaction products under more natural conditions. Two experiments were additions of a whole synthetic oil to microcosms and ponds, respectively, as a single contaminant release. Two other experiments involved continuous releases of a whole coal liquid to...

Models sharing a common bioenergetics framework have been used to address concerns about toxic chemicals and their effects on the health of aquatic communities. A basic bioenergetics formulation has been expanded to study the dynamics of contaminants in fish, to forecast the fate of polynuclear aromatic hydrocarbons (PAHs) in aquatic systems, to es...

This report presents an analysis of the risks to fish, water quality (due to noxious algal blooms), crops, forests, and wildlife of two technologies for the indirect liquefaction of coal: Lurgi and Koppers-Totzek gasification of coal for Fischer-Tropsch synthesis. A variety of analytical techniques were used to make maximum use of the available dat...

Comparisons were made between the ecological effects of phenolic compounds measured in experimental ponds and the effects forecast by aquatic ecosystem models. The Standard WAter COlumn Model (SWACOM) was used to extrapolate acute toxicity data to estimated changes in production of phytoplankton, zooplankton, and forage fish in relation to oil expo...

This report contains results of a risk analysis study of 38 categories of chemical contaminants (Risk Analysis Units (RACs)) that may be released to the environment by synthetic fuels production facilities. The analysis includes modeling of the environmental transport and fate of contaminants in the atmosphere and in surface water, and quantificati...