Division research addresses the needs of EPA and its partners in development of improved approaches for assessing the health of freshwater ecosystems and ecosystem sustainability. Research is aimed at providing improved designs, indicators, and methods for monitoring and assessment of complex aquatic ecosystems. Studies examine relationships between watersheds and receiving waters, as well as relationships among units of large systems. Specific stressors include nutrients, habitat alteration, and invasive species, as well as multiple stressors. Research on sustainability seeks to demonstrate how human communities benefit from healthy ecosystems and how social and economic conditions are linked to environmental services and benefits.
Predictive toxicology is increasingly needed for the sustainable managment of chemicals in our society. A vast array of chemicals are in current or proposed use, and efficient and effective testing is needed for toxicity prediction and prioritization for risk assessment. Division research programs focus on aquatic life utilizing adverse outcome pathways (AOPs) of classes of chemicals which provide a means for quantifying the cascade of chemical effects from molecular initiating events to ecosystem outcomes. Models of adverse outcome pathways are developed using chemical structure activity relationships (SAR); physiological responses (physiologically-based, toxicokinetic (PBTK) models); biological systems models, incorporating molecular, cellular, tissue, whole organism and population linkages; and predictive metabolism and metabolite toxicity. Research tools employ in vitro, in vivo, and molecular endpoints and computational analyses. Predictive approaches for risk assessment are developed for applications in aquatic life criteria, remediation of contaminated sites, and large-scale and long-term ecosystem restoration. Ecosystem response models are developed to assist EPA and its partners in addressing large and expensive environmental remediation problems and in considering alternative futures associated with environmental protection and management.