This NOAA study was one of the eight selected for funding by the St. Lucie River Issue Team (SLRIT) in the Year 2000. The study purpose was to characterize St. Lucie Estuary in terms of environmental toxicity and to describe the extent and severity of habitat degradation using the sediment quality triad approach. The study was specifically designed to monitor and assess the concentrations, distributions, and biological effects (including potentially multi-generational genotoxic damage) of multiple stressors in the St. Lucie Estuary and its environs. The study addressed various aspects of key environmental issues that have been defined for the estuary, including possible impacts from agricultural runoff (i.e., those from citrus groves and row crops), urbanization and probable relationships between prevalence of fish abnormalities and severity of contamination.