CHEMICAL ELEMENT ACCUMULATION IN TREE BARK GROWN IN VOLCANIC SOILS
The semi-arid Cape Verde archipelago has incipient soils with high potential of imbalance of chemical elements due to diverse magmatic events. Nevertheless these volcanic soils are a valuable resource of these islands for agriculture. So the eventual impact on the health of plants and animals must be evaluated. A first assessment of elements uptake by plants grown in the island of Fogo was done using acacia bark as biomarker. High EFs found for some chemical elements in barks are certainly of geogenic origin rather than anthropogenic since industry and the use of fertilizers is scarce. Among REE, the heavy ones are significantly enriched, which agrees with their release after the primary minerals breakdown with formation of more soluble compounds than the other REE. These results show how biogeochemistry may contribute to the REE fractionation in the critical zone.