Cycling and Speciation of Mercury in the Food Chain of South Florida

Methylmercury, a neurotoxin, is found in the game fish of south Florida. Samples of periphyton, the assemblage of microalgae that live in shallow submerged substrates which is home to, and food for, creatures that are the foundation of the food chain, have concentrations of methylmercury that range from non-detectable to tenths of a part per million on a dry weight basis. The report produced from this project presents data for samples of periphyton and water collected in 1995 and 1996 from Water Conservation Areas, the Big Cypress National Preserve, and the Everglades National Park in south Florida. Periphyton samples were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Water-column samples collected on the same dates as the periphyton samples were analyzed for concentrations of major ions.