Biomonitoring of Environmental Status and Trends (BEST)
Large Rivers Monitoring Network (LRMN)

  The Biomonitoring of Environmental Status and Trends (BEST) Program's Large River Monitoring Network (LRMN) has examined fish health in multiple river basins by using a suite of organismal and suborganismal endpoints, which monitor and assess the effects of environmental contaminants in fish. As a national monitoring program, BEST-LRMN is unique in that it utilizes biomarkers to evaluate less persistent chemicals in the environment and to detect molecular-level changes before population effects may be evident.
Access BEST-LRMN data by:
Basin Contaminant Biological Endpoint



Click on a basin or on a link below to search
by station number in that basin
Columbia River Basin Colorado River Basin Southeastern US River Basins Southeastern US River Basins Rio Grande Basin Mississippi River Basin Yukon River Basin


This searchable dataset currently contains the following information:

  • Contaminant concentrations (elemental and organochlorines)

  • Fish health indicators (condition factor, somatic indices, health assessment index, macrophage aggregate parameters)

  • Reproductive biomarkers (steroid hormones, vitellogenin, gonadal histology)

Biochemical, physiological, morphological, and histopathological endpoints were chosen to integrate responses at multiple levels of biological organization. These data have been compared spatially and temporally by examining trends of various persistent contaminants and incorporating existing information from other monitoring efforts.


  • Large River Monitoring Synthesis Publications (other LRMN publications are accessible online in each river basin depicted on the U.S. map)

Relations Between and Among Contaminant Concentrations and Biomarkers in Black Bass (Micropterus spp.) and Common Carp (Cyprinus carpio) in Large U.S. Rivers, 1995-2004 Journal of Environmental Monitoring, Oct 2008