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EPA is responsible for implementing the Toxic Substances Control Act (TSCA and Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). These laws give EPA the responsibility to register chemicals and various biologically-active "agricultural" substances to ensure their safe use, and ensure that humans and ecological systems remain healthy after these substances have been approved for use. In the EPA Office of Research and Development (ORD), the Safe Communities Ecological Effects Research Program addresses these risk issues. The purpose of this research program is to evaluate the effects of environmental exposures and their consequences on wildlife and plant species for both individual anthropogenic stresses and combinations of anthropogenic and natural stresses. Through this research program, ORD develops the methods to evaluate effects that are used in the regulation of pesticides and toxic substances in ecosystems. Both TSCA and FIFRA mandate that EPA issue test methods guidelines, and that those guidelines be periodically updated to incorporate scientific advances. This research program will develop and validate methods and models to identify, characterize, predict and assess ecological effects, and will culminate in more holistic risk assessment and risk management strategies for use by the Office of Pesticide Programs (OPP) and the Office of Pollution Prevention and Toxics (OPPT).


In recent years, with the rapid advances made in molecular genetics, highly-specific, low-dose pesticides are being developed. Such compounds pose new concerns for the Agency since current testing guidelines are inadequate to address the wide variety of new ecological circumstances that are possible because of the use of these compounds. Typically, application rates of these low-dose substances are such that traditional, chemical analytical methods fail to detect the compounds in the environment. Two critical issues have been expressed by the pesticides program office concerning this new generation of pesticides: 1) new evaluation methods for the registration process, and 2) new methods to identify the presence and ecological consequences of releasing such low-dose herbicides. Similarly, recent advances in molecular biology and biotechnology are producing plant varieties with genetic modifications which provide them with traits such as tolerance to insects, herbicides and plant diseases. There are critical needs to develop methods to assess the extent of gene flow from genetically-modified crops and its potential ecological effects on nontarget crop, weedy and native plant species; plant community composition and functions, above and below ground; invertebrate and vertebrate pollinators and herbivores; and on wildlife habitat


EPA is faced with two ecological, scientific questions concerning pesticides and toxic substances:

1. What are the relevant, efficient and up-to-date test guidelines to use in the registration process to evaluate new chemicals?

2. How can these low-dose chemical compounds ormodified genes be detected in the environment in order to provide continued oversight of their use and safety after they have been released commercially?

Both of these scientific questions apply to both target and non-target species, including plants and animals, with both direct and indirect exposures to pesticides, toxic chemicals or genetically modified plants. Regardless of the species of interest (i.e., assessment endpoints), inherent in the evaluations is the necessity to include supporting ecosystem components and processes.




Project Leader : David Olszyk, Phone - 541-754-4397, E-Mail - olszyk.david@epa.gov

Principal Investigators:

Research Support:

The goal of this project is to provide the EPA’s Office of Pesticide Programs (OPP) with scientifically credible information and methods they can use to assess ecological risks from chemical pesticides and genetically engineered plants. These chemical compounds and biological pesticides are regulated under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The Toxic Substances Control Act (TSCA), and the Federal Food, Drug and Cosmetic Act (FFDCA), administered by the Office of Pollution Prevention and Toxics (OPPT) also provide for protection of the environment from chemicals and biological pesticides. In the past, the protection of ecological resources has received minimal attention under these regulations compared to human health assessments. Recently awareness of adverse effects from drift of new low-dose high-toxicity herbicides to non-target crop and native vegetation has heightened awareness of the need to improve tests for effects of chemical herbicides to plants. Similarly, public concern regarding the release of genetically-engineered plants and the adoption of the "Final Rules and Proposed Rules for Plant-Incorporated Protectants" have emphasized the need for tools to evaluate the risk from engineered plants and gene flow from engineered crops to other plant species.

This research project supports continued development and refinement of probabilistic risk assessment methods for evaluating potential ecological risks from proposed or existing plant pesticidal products. To accomplish this, the project is developing tools to improve the Problem Formulation, Analysis and Risk Characterization phases of ecological risk assessments. These tools are: (1) a platform for regional scale analysis of chemical pesticide and gene flow effects, (2) protocols to determine effects of chemical pesticides on terrestrial plants (focusing on herbicides), (3) methodology to track flow of genes from GM plants to other plants, and (4) models to predict ecological effects of chemical pesticides and gene flow in agricultural and nonagricultural ecosystems. With these tools, ecological risk assessments will be better able to predict potential effects of chemical pesticides and engineered plants to important ecological endpoints: crop yield, and native plant contributions to ecosystem structure, function, and wildlife habitat. To produce the assessment tools, this project is conducting research in three key areas: Regional Analysis and Interpretation, Test Methods for Chemical Herbicides on Terrestrial Plants, and Gene Flow.

The Regional Analysis and Interpretation Research develops a Geographic Information System (GIS) platform to use in Problem Formulation and Risk Characterization phases of assessing risks from chemical herbicides and GM crops. The GIS research will provide tools for spatially locating plant species potentially at risk from use of a new product, as well as phenology of non-target plants relative to pesticide application timing. These will provide bases for selecting appropriate test species and response endpoints. The GIS platform will then be used to characterize risk, by combining exposure models and relevant plant response data in a probabilistic framework. As part of this regional analysis effort, plant response outputs relevant to ecosystems (e.g. species composition, productivity) will be developed as possible input parameters for wildlife habitat models being constructed by other WED projects.




The Terrestrial Plants and Chemical Herbicides Test Research will use the GIS framework to identify crop and native plant species on a regionally important basis. Experimental protocols for herbicide exposures studies will be refined for application to nontraditional species (e.g. perennials or woody species) and additional endpoints (yield or other reproductive parameters). Research also will be conducted to develop molecular or cellular tools to extrapolate responses to non-tested species or to verify field exposures. The plant test research will use low-dose, high-potency herbicides, as well as some high-volume compounds, because evidence for current test guidelines appear inadequate for measuring reproductive responses to the low-dose herbicides.

The Gene Flow research is developing molecular methods to assess genes, evaluate dynamics of gene flow from engineered to non-engineered plants, measure potential ecological effects of gene flow, and define inputs for a prototype model for gene flow. Experiments will be conducted at various scales, including contained laboratory and growth chamber environments, and field tests. Current advances in genomics and proteonomics are being evaluated for their ability to produce new tools to diagnose both gene flow and subsequent adverse effects on crop and non-crop plants.

Overall, this research will provide tools to the EPA to help sustain the productivity of agricultural crops while maintaining the ability of ecosystems to support wildlife and to carry out other essential services. This research is needed to assist the EPA in its regulatory role as the agency responsible for registration and re-registration of chemical pesticides and GM crops that produce chemical pesticides, and in investigating field incidents where herbicides or GM plants allegedly have damaged non-target plants. It also will provide new general plant effects, molecular biological, and modeling tools which will be useful not only for determining ecological effects of pesticides and gene flow, but for characterizing risks from other environmental stresses to terrestrial ecosystems.

Pesticide Drift Case Study  This project studied the potential risk of herbicide drift and accidentally damaging neighboring crops or surrounding native vegetation.  It is the first to use the California Pesticide Use Reporting Database within a mapping  framework (known as a Geographic Information System, or GIS) to perform a risk assessment of pesticide spray drift at the county level. EPA defines pesticide spray drift as the wind-driven movement of pesticide particles in the air to unintended sites at the time of application. Many of the problems created from pesticide spray drift are controllable by human decisions which makes application of standard probabilistic risk assessment techniques difficult. In order for a pesticide application to cause damage to nontarget crops growing in fields adjacent to the target field, the pesticide must be applied at the time of increased plant sensitivity. Consequently, the study of pesticide spray drift effects on sensitive crops is data-intensive and requires spatially- and temporally-explicit information on pesticide applications in agricultural production. The objectives of this analysis were: to identify the data needs for a GIS-based model for assessing the ecological risk of pesticide spray drift at broad spatial scales; to identify the high potential risk herbicides and their effects on sensitive crop species; and identify the primary sources of uncertainty and variability in a spatially-explicit risk assessment model for pesticide drift.

For a PDF copy of the full study report, click here.

Contacts: Dr. E. Henry Lee (541-754-4832), Dr. David M. Olszyk (541-754-4397), National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon


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