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Ecotoxicology & Ecosystem Research Program
Ecosystem Analysis and Assessment
The Division addresses the needs of EPA and its partners by developing improved
approaches to assess the health of freshwater ecosystems. Research is aimed
at providing improved designs, indicators, and methods for monitoring and assessment
of complex aquatic ecosystems. Division researchers perform studies to examine
relationships between watersheds and receiving waters, as well as relationships
among units of large aquatic systems. This research focuses on specific stressors – components
of the environment such
as nutrients, habitat alteration, and invasive species - that when changed,
negatively impact ecosystems as well as the effects of multiple stressors.
Ecosystem services – those
functions and properties that directly or indirectly benefit human well-being – are
a subject for research, as well.
Ecosystem Modeling
The Division develops ecosystem response models to assist EPA and its partners
in addressing large and complex or expensive environmental
remediation problems. These models are used when considering alternative
futures associated with environmental protection and management strategies.
Researchers develop bioaccumulation models to predict the effects of complex
environmental media, such as sediments, on toxicity to food webs and to forecast
the efficacy of remediation, including the associated ecosystem responses.
Forecasting scenarios for alternative management or remediation are addressed
using multi-media-based, spatially explicit mathematical models. Model scenarios
include “status
quo management” and
specific alternative remediation actions to assist decision-makers. The Division
has developed ecosystem response and forecasting models to address pollutant
effects in the Great Lakes. Models are being adapted for other large ecosystems,
such as the Gulf of Mexico, and for additional pollutant types and sources.
To learn more about this research, visit the U.S.
EPA Large Lakes Research Station.
Predictive Toxicology and Modeling
Division research aims to improve toxicity prediction and prioritization of
chemicals for toxicity testing to assist EPA and its partners to undertake
effective risk assessment for the vast array of chemicals in use today. Division
researchers are advancing our understanding of the mechanism-of-action (MOA)
of classes of chemicals, with a focus on aquatic life. A variety of toxicological
models are developed by the Division. These include chemical structure activity
relationships (SAR) models; physiologically-based, toxicokinetic (PBTK) models;
biological systems models that incorporate molecular, cellular, tissue, whole
organism and population linkages; and predictive metabolism and metabolite
toxicity models. Research tools include in vitro, in vivo, molecular endpoints,
and computational analyses.
Toxic Effects Assessment
Division research serves EPA and its partners through scientific advancements
to improve guidance for water quality criteria and standards to protect aquatic
life. Improving the information quality and content of assays required for
chemical testing and approval has long been a Division strength. Researchers
develop methods and tools to assess the toxic effects of chemicals on life
in both fresh water and aquatic sediment. Division efforts support improved
access to high quality data or models that predict the causes of toxicity
and its effects on ecosystems. The ECOTOX Knowledge System is supported as
a research tool for hypothesis testing and as a repository for high quality
data to be used in chemical risk assessments.