Evaluation of Selected Histologic and Immunologic Biomarkers in Fish Collected for the BEST pilot program in the Mississippi

This study is part of a larger project entifled Biomonitoring of Environmental Status and Trends (BEST) Program: Testing and Implementation of Selected Aquatic Ecosystem Indicators in the Mississippi River System, 1995. This pilot project includes assessment of a variety of biomarkers of which we are responsible for the histologic and immunologic markers. During the period in which concentrations of persistent contaminants were declining, the use of and concerns about other chemicals, especially those that do not accumulate in biota, increased. At least part of this concern stemmed from increasingly frequent reports of fish kills and avi an wildlife mortality incidents related to the use of soft pesticides-highly toxic, but short-lived organophosphate and carbamate insecticides that do not accumulate (e.g.; Glaser 1995). Herbicides are also now widely distributed in surface and ground waters of agricultural areas. Information was obtained from http://www.lsc.usgs.gov/