Pinus needles as bioindicators of organic micropollutants
(1) LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal, (2) ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
The utility of Pinus needles as bioindicators of the presence of organic and inorganic contaminants in the environment has been reported from the 1980s onwards. Their unique properties, based on a superficial waxy layer and a perennial status (lifetime up to several years depending on the species) are particularly helpful to assess airborne gaseous organic micropollutants with a wide spatial and temporal span. For almost 20 years we have been conducting at LEPABE several studies with this matrix which, as almost all natural materials, involves complicated analytical methodologies to extract and quantify the target chemicals. This study intends to show the main highlights of this research line, including the new perspectives we intend to follow. In the beginning, PAHs were our aim, but in time we were able to develop multicomponent protocols that allowed us to study five more families of semivolatile organic compounds (SVOCs), including legacy pollutants and chemicals of emerging concern such as volatile methylsiloxanes or synthetic musks. Green Analytical Chemistry principles have been framing our constant optimization of the sample handling and extraction procedures, that went from commercial alumina solid-phase extraction SPE cartridges, to custom-made glass columns and finally the much more sustainable QuEChERS approach. GC-MS was always the choice for the quantification step. Under this umbrella it was possible to investigate, among others, levels, spatial and temporal trends, sources of several SVOCs in countries like Portugal, Spain, Greece, Norway, the UK, and Iceland, and even incorporate the obtained data into modelling solutions for atmospheric chemistry. After all this time, we still believe Pinus needles are a valuable tool for the monitoring of airborne pollutants, even more now when we need all help to tackle the climatic changes upon us. Future work involves the incorporation of this matrix in the study of wildfires, a devastating problem in many countries, particularly in the Mediterranean basin. Acknowledgements This work was financially supported by: LA/P/0045/2020 (ALiCE – Associated Laboratory in Chemical Engineering) and UIDB/00511/2020 and UIDP/00511/2020 (LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy), funded by national funds through FCT/MCTES (PIDDAC).
Keywords: Pinus needles, bioindicator, organic micropollutants, atmospheric chemistry
