Biokinetics of selected heavy metals and radionuclides in two marine macrophytes: the seagrass Posidonia oceanica and the alga Caulerpa taxifolia

摘要: Uptake and loss kinetics of Zn, Ag, Cd, 134Cs, 241Am by shoots the seagrass Posidonia oceanica fronds green alga Caulerpa taxifolia were determined in controlled laboratory radiotracer experiments using low contaminant concentrations. The two species accumulated most elements efficiently. only exceptions 134Cs both P. C. Cd Taxifolia (concentration factors ⩽ 6.4). Steady state uptake was reached for each element except Ag. In oceanica, steady noted Ag whereas linearly during course experiment (15 d). With respect to relative metal bioavailability, different compartments generally ranked order: leaf epiphytes > adult leaves = intermediate sheaths. long-lived component characterized a relatively short biological half-life (Tb12 28 However, observations individual indicated that had high retention capacity with virtually 100% retained after 21 d uncontaminated sea water. taxifolia, Tb12 value not significantly from infinity, an observation which suggests substantial fraction or radionuclide incorporated contamination event would be irreversibly bound this algal species.