The Impact of Eelgrass on Heavy Metal Mobilization

摘要

Release of cadmium and manganese radionuclides from eelgrass leaves and root-rhizomes into seawater and seawater plus disodium ethylenediaminetetraacetate (EDTA) was monitored over periods of six hours following incubations of 1 to 98 hours. Flux of both isotopes from tissues is initially rapid, and enhanced by the addition of EDTA. Manganese apparently is released more slowly during latter phases of release, pointing to greater biological accumulation potential. Cadmium and manganese radionuclide uptake by Zostera marina L. tissues and translocation between root-rhizomes and leaves was examined. Cadmium concentrations in root-rhizomes increased with incubation time but appeared to reach saturation levels at 24 hr of exposure. Translocation of cadmium between root-rhizomes and leaves was observed to occur in both directions. A greater flux of cadmium downward was noted and root-rhizomes appear to be a cadmium sink.