Field Survey of Heavy Metal Uptake by Naturally Occurring Saltwater and Freshwater Marsh Plants

摘要

A natural marsh heavy metal survey was conducted to establish a baseline for comparison to plant concentration and uptake data from contaminated and perturbated sediments. Extensive field sampling of natural marshes was conducted along the East and gulf coasts of the United States, and along the shores of the Great Lakes. Spartina alterniflora was collected from the saltwater marshes and Cyperus species were collected from the freshwater marsh areas. Results indicated that, in the saltwater marsh, manganese and zinc concentrations were slightly lower than those previously determined in greenhouse and disposal site studies with contaminated sediments, while the concentrations of the remainder of heavy metals were similar. Calculation of total uptake values indicated that only cadmium may be of concern. Cadmium levels in Cyperus species in naturally occurring marshes were similar to those of a greenhouse flooded (reduced) environment. Iron and manganese were generally present in lower concentration in the natural marsh than in the greenhouse plants grown on contaminated sediment, while the remainder of the heavy metals examined were present in higher concentrations.