A comparative study on biological remediation of a co-contaminated soil by natural attenuation, phytoremediation, bioaugmentation and bioaugmentation-assisted phytoremediation

AGNELLO, A. C.; BAGARD, M.; VAN HULLEBUSCH, E.D.; ESPOSITO, G.; HUGUENOT, D.

Roma

Workshop; Bonifica, recupero ambientale e sviluppo del territorio: esperienze a confronto sul fitorimedio?; 2016

Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA)

Biological remediation technologies are an environmentally friendly approach for the treatment ofpolluted soils. This study evaluated through a pot experiment four bioremediation strategies: a) naturalattenuation, b) phytoremediation with alfalfa (Medicago sativa L.) c) bioaugmentation withPseudomonas aeruginosa, and d) bioaugmentation-assisted phytoremediation, for the treatment of aco-contaminated soil presenting moderate levels of heavy metals (Cu, Pb and Zn at 87, 100 and 110mg kg-1 DW, respectively) and petroleum hydrocarbons (3800 mg kg-1 DW). As demonstrated by plantbiomass and selected physiological parameters alfalfa plants were able to tolerate and grow in the cocontaminatedsoil, especially when soil was inoculated with P. aeruginosa, which promoted plantgrowth (56 % and 105 % increase for shoots and roots, respectively) and appeared to alleviate plantstress. The content of heavy metals in alfalfa plants was limited and followed the order: Zn > Cu > Pb.Heavy metals were mainly concentrated in plant roots and were poorly translocated, favouring theirstabilization in the root zone. Bioaugmentation of planted soil with P. aeruginosa generally led to adecrease of plant metal concentration and translocation. The highest degree of total petroleumhydrocarbon removal was obtained for bioaugmentation-assisted phytoremediation treatment (68 %),followed by bioaugmentation (59 %), phytoremediation (47 %) and natural attenuation (37 %). Theresults of this study demonstrated that the combined use of plant and bacteria was the mostadvantageous option for the treatment of the present co-contaminated soil, as compared to naturalattenuation, bioaugmentation or phytoremediation applied alone.