Reduced bioaccumulation of PAHs by Lactuca satuva L. grown in contaminated soil amended with sewage sludge and sewage sludge derived biochar
Abstract: The influence of sewage sludge (SS) and sewage sludge biochar (SSBC) upon biomass yield and the bioaccumulation of PAHs into lettuce plants grown in contaminated soil (∑16PAH 20.2 ± 0.9 mg kg−1) is presented. All SSBC amendments (2, 5 and 10%) and the 2% SS amendment significantly (P < 0.01) increased lettuce biomass. Both SS and SSBC amendments significantly reduced (P < 0.01) the bioaccumulation of PAHs at all application levels; with reduction in ∑16PAH concentration ranging between 41.8 and 60.3% in SS amended treatments and between 58.0 and 63.2% in SSBC amended treatments, with respect to the control. Benefits in terms of biomass production and PAHs bioaccumulation reduction were greatest where SSBC was used as a soil amendment. At high application rates (10%) SSBC reduced bioaccumulation of PAHs by between 56% and 67%, while SS reduced bioaccumulation of PAHs by less than 44%.
