STUDY OF HEAVY-METALS AND OTHER ELEMENTS IN MACROPHYTE ALGAE USING ENERGY-DISPERSIVE X-RAY-FLUORESCENCE

Fuscus vesiculosus L. seaweeds from three estuarine stations were anal yzed by X-ray fluorescence, providing results for the concentration of total K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sr, and Pb. Four dif ferent structures of the algae (base, stipe, reproductive organs, and growing tips) were analyzed to study the differential accumulation of heavy metals by different parts of Fucus. Some elements (e.g., Cu and Fe) are preferentially accumulated in the base of the algae, whereas o thers (e.g., As) exhibit higher concentrations in the reproductive org ans and growing tips. The pattern of accumulation in different structu res is similar for Cu, Zn, and Pb, but for other metals there is consi derable variability in accumulation between parts of the plant. This i s important in determining which structures of the plant should be use d for biomonitoring. For samples collected at stations subject to diff ering metal loads, the relative elemental composition is approximately constant, notwithstanding significant variation in absolute values. T he proportion of metals in Fucus is similar to that found in other est uaries, where metal concentrations are significantly lower. Energy-dis persive X-ray fluorescence has been shown to be a suitable technique f or multielement analysis in this type of sample. No chemical pretreatm ent is required, minimizing sample contamination. The small amount of sample required, and the wide range of elements that can be detected s imultaneously make energy-dispersive X-ray fluorescence a valuable too l for pollution studies.