Cd and Zn uptake in macrophyceae from Greek coasts

Summary In the frame of a project financed by the General Secretariat of Research and Technology, the Institute of Botany has undertaken to measure the degree of pollution in the marine area by means of physicochemical and biotic parameters. Bioaccumulation of heavy metals in the macrophyceae has also been examined. Since the latter are immobile, they form strong indicators of pollution for the respective biotopes. Comparing the measurements carried out in marine macrophyceae obtained from the Gulf of Kavala and Pylos, we have made the following conclusions. Seasonal variations were detected in the Cd and Zn content of nine marine macrophyceae species which had already been investigated. Cadmium, one of the toxic metals, was, in certain cases, present in a large number of species. Fluctuations in the quantities were seasonally detected, but more obvious differences were those between species from different classes of macrophyceae. In contrast, the amount of Zn was generally lower. When we compared the values of Zn to those of Cd in the same algal species, we detected an antagonism between them (i.e. higher values for Cd were accompanied by lower values for Zn). Finally, on comparing the biotopes, we found there was slightly more Cd in Pylos than in Kavala. In the harbour of Kavala, in particular, where there is strong evidence of domestic sewage, the amount of Cd is very low. It is well known that Cd is derived mostly from industrial waste waters; in the city of Kavala, the domestic waste does not include high quantities of heavy toxic metals.