United States Environmental Protection Agency Office of Research and Development National Exposure Research Laboratory Research Abstract Government Performance Results Act (GPRA) Goal 2 Annual Performance Measure #253 Significant Research Findings: Statistical Guidance for Developing Indicators for Rivers and Streams: A Guide for Constructing Multimetric and Multivariate Predictive Bioassessment Models The USEPA's National Biological Criteria Program began in 1988 to help fulfill the objective of the Clean Water Act to restore the physical, chemical, and biological integrity of the Nation's waters. Since that time, the USEPA has published guidance on a variety of scientific and technical aspects of bioassessments and biocriteria including: bioassessment protocols for streams and wadeable rivers; development of biocriteria for streams and small rivers; development of biocriteria for lakes and reservoirs; and development of biocriteria for estuaries. Through communication with States and EPA Regional coordinators, biocriteria are being promoted by the EPA's Office of Water since they provide a more effective measure of ecological condition and water quality compared to conventional physical and chemical criteria alone. EPA's Office of Water has determined that a critical need for the continued implementation of biocriteria is a guidance document detailing the data analysis methods used to develop biological indices and establish numerical biocriteria. Several approaches have been used to develop biological indices, but there is no clear guidance for Regional, State and Tribal biologists to select the approach that is most appropriate for their data, and to conduct the analysis. The purpose of this project is to provide a statistical guidance document for developing biological indicators and setting biocriteria. The guidance is intended to provide Regions, States and Tribes with tools that are statistically sound and defensible for determining if water bodies meet designated aquatic life uses. The primary objective of this guidance is to enable Regions, States and Tribes to select a statistical approach for developing a bioindicator that is most appropriate for their data, to conduct the analyses to develop the indicator, and to use the indicator to set biocriteria. Two common statistical methods to construct an indicator using biological data were identified for inclusion in the guidance: a multimetric assessment using an index that is the sum of several individual metrics and an assessment comparing actual species composition at a site to an idealized reference site predicted from a multivariate statistical model, River In Vertebrate Prediction And Classification System (RIVPACS). These two approaches were selected because they use community and assemblage data, they are not restricted to any one assemblage and they have been used by several agencies in many areas. Scientific Problem and Policy Issues Research Approach ------- For each method, an introductory overview is presented, followed by a case study using data from a state biomonitoring program to develop the index. The final chapter, "From Analysis to Criteria", includes several examples of setting biocirtieria using both types of indices. Results and Currently, there is no statistical guidance available that specifically addresses the Impact development of bioindicators and setting biocriteria. The Office of Water identified the lack of such guidance as a critical need for the continued implementation of biocriteria by Regions, States and Tribes. A guidance document providing step-by-step approaches for the developing bioindicators for use in water quality monitoring meets this need and furthers the agency's goal of promoting the use of biocriteria to more effectively protect and restore ecosystems and water quality. To further assist stakeholders in developing indicators and setting biocriteria, case studies using actual monitoring data from states are included in the document. Ecological Exposure Research Division (EERD) research staff are the technical and project leads for this research. Tetra Tech, Inc. provided technical writing and technical input through contract to the Office of Water. Representatives from Regions, States and the Office of Water were included in an initial review of the document. The Biocriteria and Nutrient Session: "Charting a Statistical Course for Navigating the Murky Waters of Bioindicator Development" that was conducted at the Regional/ORD Workshop on Aquatic Life Criteria, Seattle, WA, December 4-7, 2001 was used as a forum to present material that is included in the guidance document. Feedback from session participants was used to refine content. Future Research This document will be included in EPA's Office of Science and Technology's document "Methods for the use of statistics in bioassessments and biocriteria development". Questions and inquiries can be directed to: Florence A. Fulk U.S. EPA, Office of Research and Development National Exposure Research Laboratory 26 West Martin Luther King Drive Phone:513/569-7379 E-mail: fulk.florence@epa.gov Federal funding for this research was administered under EPA contract number 68-C-04-004 with TetraTech, Inc. Research Collaboration and Research Products Contacts for Additional Information ------- |