South Florida Mercury Science Program:

The purpose of this project was to demonstrate the technical feasibility of conducting a Total Maximum Daily Load (TMDL) analysis for a system where the contaminant of interest is derived principally from atmospheric sources. Depending on the type of aquatic system, a number of contaminants may be categorized as significantly atmospheric in origin, including mercury, fixed nitrogen, PCB’s, and others. This study focuses on mercury, and incorporates extensive field data into a framework combining atmospheric mercury deposition and aquatic mercury cycling models to demonstrate the feasibility of the approach. The goal was to understand and simulate how changes in local atmospheric mercury emissions in south Florida would influence mercury concentrations in top predator fish, thus demonstrating the potential of combining air and water modeling approaches in TMDLs involving air deposition of mercury.