Fish Tissue Study

Map and Data for This Study

• Objective:
  To describe the occurrence of contaminants in fish tissue.
• Approach and Targeted Chemical Data:
  
  Conducted fish-tissue surveys at 24 sites in the basin. A targeted taxa (common carp, white sucker, or brown trout) was selected at each site, and 8 to 10 whole individuals were composited and submitted to the laboratory for analysis of organic contaminants. Livers also were extracted from target taxa, composited (minimum mass of 10 g) and submitted to laboratory for analyses of trace elements.
  
  
• Timing:
  
  Late summer and early fall 1992 and 1993, August 1996 and September 1997 at selected sites.
  
  
• Selected Results:
  
  Banned compounds, such as PCBs and chlordane, widely used historically in the urban setting, have been detected in fish tissue.
  
  Other banned compounds, such as DDT and dieldrin, have been detected more often and at higher concentrations in fish tissue collected in mixed land-use settings than in urban or agricultural settings.