In order to determine the current status of and to detect any long-term trends in the environmental quality of U.S. nearshore waters, NOAA initiated the National Status and Trends program in 1984 with its National Benthic Surveillance Project. The primary objective of the Benthic Surveillance Project was to quantify concentrations of a suite of organic and inorganic contaminants in the livers of fish and surficial sediments from selected sites in the coastal and estuarine waters of the United States. In addition, the levels of certain indicators of the biological effects of these contaminants were measured. Incidences of visible lesions, including fin erosion, have been noted and histopathological examinations of various tissues have been carried out. Originally histopathological examinations determined the prevalence of any identifiable disease conditions in samples of liver, kidney, and gill tissue.In addition, the Benthic Surveillance Project tested fish livers from 30 locations in 1991 to identify the concentrations of DNA xenobiotic adducts. DNA xenobiotic adducts are a bioindicator of exposure to genotoxic compounds. Measurement of biological markers such as DNA xenobiotic adducts have been used to improve the evaluation of contaminant exposure and responses in indigenous fish, and thus reinforce the connection between exposure to toxic chemicals and the observed injuries.