Greenhouse and field studies on Cr, Cu, Pb and Zn phytoextraction by Brassica napus from contaminated soils in the Apulia region, Southern Italy

In the framework of a project aiming to phytoremediate heavy metal contaminated soils in the Apulia region, Southern Italy, a series of greenhouse experiments followed by field trials were performed in order to optimize heavy metal phytoextraction by Brassica napus. The effects of root colonization by Bacillus licheniformis BLMB1 and of addition of municipal solid waste (MSW) composts on the capacity of B. napus to tolerate and accumulate Cr, Cu, Pb and Zn were evaluated. B. napus was able to accumulate high amount of metals in greenhouse conditions, whereas it grew with difficulty or not at all in the open field, and metal accumulation in plant fractions was relatively low. The accumulation of metals in the plant fractions was in the order: Cr > Zn > Cu > Pb. The presence of either compost or B. licheniformis BLMB1 strain enhanced metal accumulation, Cr in particular, in the experimental conditions used. This effect can be useful in the phytoextraction of Cr from contaminated soils.

Research Highlights
► The study area is highly polluted by heavy metals (HMs), Cr in particular.
► In the greenhouse, B. napus behaved as good accumulator for HMs, Cr in particular.
► In the field, the accumulation of HMs in plant parts of B. napus was relatively low.
► Compost and B. licheniformis enhanced B. napus accumulation of HMs, Cr in particular.
► The study suggest a very slow restoration of HMs contaminated soil by the studied B. napus.