Pioggia pollinica e qualità dell’aria: polline di Olea negli uliveti dal caso studio della regione Basilicata (sud Italia).

Gli uliveti sono un elemento fondamentale del paesaggio dell’Italia meridionale. In queste regioni, il polline di Olea è uno dei principali elementi biologici diffusi in aria e ha un notevole impatto sulla salute dell’uomo, poiché è stato riconosciuto tra le principali cause di allergia respiratoria nell’area mediterranea.Il lavoro presenta lo studio palinologico di uliveti della Basilicata, regione nella quale l’olivicoltura è ampiamente diffusa. Sono stati analizzati campioni di suoli superficiali prelevati al centro (IN) e a diverse distanze (OUT) dagli uliveti per valutare la rappresentatività del polline di Olea nell’area interessata dagli impianti.Pur essendo influenzate da diversi fattori (estensione dell’uliveto, età degli alberi, stadio al quale si trova il periodo di fioritura, presenza di polline da specie sovrarappresentate, lavorazione del terreno, distribuzione di altri uliveti nelle aree circostanti), le quantità di Olea rinvenute nei campioni sono strettamente legate alla distanza dall’uliveto. In generale, le percentuali di questo polline sono molto elevate al centro dell’uliveto (ca. 55% in media per gli uliveti più estesi) e decrescono fortemente a 500 m (ca. 6%, con un abbattimento di ca. 90%), per rimanere pressoché costanti a 1000 m. Il confronto con i dati aerobiologici dell’area (biennio 2005-2006, stazione ARPAB di Matera) conferma che il polline di Olea aerodiffuso (7-11%) è meno abbondante ma in proporzione comparabile a quello al suolo (13%).I dati raccolti forniscono un’ulteriore prova dell’importanza del polline di Olea in Basilicata, suggerendo inoltre un elevato rischio allergenico per i soggetti atopici nel raggio di 1000 m intorno agli uliveti.Pollen rain and air quality: Olea pollen in the olive groves (the case study of Basilicata, a region of southern Italy) - Olive trees are key elements of the cultural landscape of southern Italy. Olea pollen is therefore one of the main component in the biological aerosol and it is known to have important impact on human health for pollinosis in Mediterranean countries. The paper reports pollen analyses from olive groves distributed in Basilicata, a region facing the Ionian Sea, where agriculture is still largely spread. The aim of the study is to evaluate the representativeness of Olea pollen in soil samples, taken at different distances from sources. Five olive groves (A-E) have been selected along a SE/NW transect along the Bradano river, taking into consideration that they should have been at significant distance from the other olive groves of the same area. Six samples per each olive grove have been taken in the following way: a) two IN samples, including one surface sample, and one sample collected by pinches; b) four OUT samples, including two samples taken at 500 m far from the centre of the olive grove, at N and W directions and two samples taken at 1000 m, at N and W directions. Olea pollen was found in good amount in all samples but its percentages were very variable depending on several factors: olive grove extension, age of the trees, gap between period of sampling and start of pollination (April), abundance of pollen from overrepresented taxa in the spectra (Pinus), occurrence of particular agricultural practices (ploughing), spread of several olive groves or presence of wild olive specimens in the same area.Moreover, the distance of the point of sampling from the trees plays an important role in olive pollen representativeness. As expected, the highest percentages of this pollen are found at the centre of the olive groves, and then dramatically fell at 500 m, and remained fairly constant at 1000 m. The more extended olive groves (A, D) show the highest values of Olea pollen at the centre (ca. 55% on average). This high value sharply drops to ca. 5% at 500 m. Therefore, the decrease of this pollen may be estimated of about 87-92% in the first few hundred meters from the sources.Comparison with airborne pollen captured by spore-traps (years 2005-2006, monitoring station ARPAB of Matera) confirms that this pollen is generally less abundant in the air than in the soil layers. In our study case, the pollen of Olea was about 7-11% in the annual pollen rain while it was about 13% in the surface soil samples collected in and around the olive groves. Data are a further proof of the importance of this pollen in the Mediterranenan region, also suggesting a higher risk for atopic people in a radium of 1000 m around the olive groves.