NEUTRON-ACTIVATION ANALYSIS OF ELEMENTAL COMPOSITION IN A MARINE PHANEROGAM, POSIDONIA-OCEANICA (L) DELILE - A BIOLOGICAL INDICATOR OF POLLUTION

Neutron activation analysis of samples of the marine phanerogam Posidonia oceanica (L.) Delile, collected from a reference zone in Port-Cros National Park of the Mediterranean coast of France, detected 29 elements, bringing the total known elements in this plant to 43. Significant differences were found in the distribution of these elements in the leaves and flowers, as well as among the different types of leaves in the foliar bundle. The effect of pollution related to maritime activities was investigated by comparing samples from the reference zone with samples from a bay overcrowded with pleasure boats. Samples taken in the reference zone under the same conditions before and after the Chernobyl accident were compared to identify elements attributable to the nuclear power industry and in particular to that accident. The ability of Posidonia oceanica to concentrate elements from sea-water, notably those known for their biotoxicity, shows the advantage of using this plant as a biological indicator for this type of pollution. The data indicated that the reliability of the results obtained is closely dependent on the sampling methods, particularly when using a sensitive and high-resolution method such as neutron activation.