<i>Helichrysum microphyllum</i> subsp. <i>tyrrhenicum</i>, Its Root-Associated Microorganisms, and Wood Chips Represent an Integrated Green Technology for the Remediation of Petroleum Hydrocarbon-Contaminated Soils
Melinda Mandaresu,
Ludovica Dessì,
Andrea Lallai,
Marco Porceddu,
Maria Enrica Boi,
Gianluigi Bacchetta,
Tiziana Pivetta,
Raffaela Lussu,
Riccardo Ardu,
Marika Pinna,
Federico Meloni,
Enrico Sanjust,
Elena Tamburini
Affiliations
Melinda Mandaresu
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Ludovica Dessì
Centre for Conservation of Biodiversity—Department of Life and Environmental Sciences, University of Cagliari, 09123 Cagliari, Italy
Andrea Lallai
Centre for Conservation of Biodiversity—Department of Life and Environmental Sciences, University of Cagliari, 09123 Cagliari, Italy
Marco Porceddu
BG-SAR—Sardinian Germplasm Bank, HBK—Hortus Botanicus Karalitanus, University of Cagliari, 09123 Cagliari, Italy
Maria Enrica Boi
Centre for Conservation of Biodiversity—Department of Life and Environmental Sciences, University of Cagliari, 09123 Cagliari, Italy
Gianluigi Bacchetta
Centre for Conservation of Biodiversity—Department of Life and Environmental Sciences, University of Cagliari, 09123 Cagliari, Italy
Tiziana Pivetta
Department of Chemical and Geological Science, University of Cagliari, 09042 Monserrato, Italy
Raffaela Lussu
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Riccardo Ardu
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Marika Pinna
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Federico Meloni
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Enrico Sanjust
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Elena Tamburini
Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
Phytoremediation and the use of suitable amendments are well-known technologies for the mitigation of petroleum hydrocarbon (PHC) contaminations in terrestrial ecosystems. Our study is aimed at combining these two approaches to maximize their favorable effects. To this purpose, Helichrysum microphyllum subsp. tyrrhenicum, a Mediterranean shrub growing on sandy and semiarid soils, was selected. The weathered PHC-polluted matrix (3.3 ± 0.8 g kg−1 dry weight) from a disused industrial site was employed as the cultivation substrate with (WCAM) or without (UNAM) the addition and mixing of wood chips. Under the greenhouse conditions, the species showed a survival rate higher than 90% in the UNAM while the amendment administration restored the totality of the plant survival. At the end of the greenhouse test (nine months), the treatment with the wood chips significantly increased the moisture, dehydrogenase activity and abundance of the microbial populations of the PHC degraders in the substrate. Cogently, the residual amount of PHCs was significantly lower in the UNAM (3–92% of the initial quantity) than in the WCAM (3–14% of the initial quantity). Moreover, the crown diameter was significantly higher in the WCAM plants. Overall, the results establish the combined technology as a novel approach for landscaping and the bioremediation of sites chronically injured by PHC-weathered contaminations.
