Biogeochemical response of Pinus brutia and Olea europaea to lithological variations and Cu mineralisation in Cyprus

Regional geochemical mapping programs are predominantly based on regolith materials as the sampling media. The use of plant organs has been more limited, despite potential advantages demonstrated in more localised studies that have examined biogeochemical responses to various types of mineralisation or contamination, or sought to identify species with phytoremediation potential. This study investigated the effects of variations in lithology and mining wastes on the multielement chemistry of Pinus brutia (pine) needles and O. europaea (olive) leaves, obtained from low-density traverses across Cyprus and detailed sampling around two Cyprus-style VHMS Cu-deposits. A total of 476 samples were analysed by a combination of inductively-coupled plasma mass spectrometry (ICP-MS) and portable X-ray fluorescence spectrometry (pXRF). At the regional scale there are substantial differences in the composition of the pine needles, especially for Ni, Ba, Sr, Mn and Zn, between the major lithological groups that range from the ultramafic and mafic units of the Troodos Ophiolite to the mineralised pillow basalts and various marine carbonate units. Both pine needles and olive leaves display intense Re anomalies in areas with mine wastes and consistently low concentrations in background areas. The response for Cu and other macro- or micronutrient elements to contamination is less pronounced and may reflect barriers to uptake by the plants. The relative magnitude of variations between the different lithologies in median plant metal concentrations is equivalent to that displayed in soils of the Geochemical Atlas of Cyprus (e.g. REE, Zn and Sr), but for some elements the patterns differ substantially. There is close correlation between the ICP-MS and pXRF data for elements where most values are above pXRF detection limits. The study further demonstrates the potential of plants in regional geochemical mapping for a range of applications, in combination with or as an alternative to conventional regolith media.