The influence of various biochars on the bioaccessibility and bioaccumulation of PAHs and potentially toxic elements to turnips (Brassica rapa L.)

• Published in: Journal of hazardous materials Vol. 300; pp. 243 - 253
• Main Authors: Khan, Sardar, Waqas, Muhammad, Ding, Fenghua, Shamshad, Isha, Arp, Hans Peter H., Li, Gang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.12.2015
• Subjects: Arachis; Arachis hypogaea; arsenic; Arsenic - metabolism; Bioaccumulation; bioavailability; biochar; Biochars; Brassica napus - drug effects; Brassica napus - growth & development; Brassica napus - metabolism; Brassica rapa; cadmium; Charcoal - pharmacology; copper; cost benefit analysis; crop yield; feedstocks; lead; Metals, Heavy - metabolism; peanuts; polluted soils; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - metabolism; Potentially toxic elements; rice straw; sewage sludge; soil amendments; Soil Pollutants - metabolism; soybeans; toxic substances; Turnip; turnips; zinc; RSB; C; SSBC; N; DCM; S; ASE; Polycyclic aromatic hydrocarbons; Bioaccumulation; SBBC; PTEs; Potentially toxic elements; PAHs; DOC; Turnip; PNBC; Biochars; EC
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2015.06.050

[Display omitted] •The influence of biochar amendments to turnips grown on urban soil was tested.•The tested biochars reduced the bioaccessibility and bioaccumulation of PAH and PTE.•The reduction of bioaccessibility was more substantial for PAHs than PTEs.•Peanut shell biochar was the most effective at reducing PAH and PTE bioaccumulation.•2% biochar additions increased the turnip yield, though 5% additions decreased it. The influence of amending a contaminated soil with different dry-pyrolyzed biochars on the bioaccessibility and biouptake of polycyclic aromatic hydrocarbons (PAH) and potentially toxic elements (PTE) in turnip (Brassica rapa L.,) was investigated. This is the first study to examine the influence of biochar amendments on turnips grown in a contaminated soil. The biochars came from different local feedstocks, including sewage sludge biochar (SSBC), soybean straw biochar (SBBC), rice straw biochar (RSBC) and peanut shell biochar (PNBC). The biochars were applied to soil at 2% and 5% amendments, and the resulting influence on various soil and porewater properties were quantified. The bioaccessible concentrations of PAHs in soil and their bioaccumulation in B. rapa L. significantly (P<0.05) decreased in the biochar amended soils. Biochar additions significantly (P≤0.05) reduced the bioaccumulation of PTEs (As, Cd, Cu, Pb and Zn) in B. rapa L, though not as much as for PAHs. The most effective biochar at reducing both PAHs and PTEs was PNBC (P≤0.05). Amendments of 5% biochar were more effective at reducing contaminant bioaccessibility than amendments at 2% (P<0.05). Crop yield, however, increased the most for the 2% biochar amendments, in particular for SSBC (with a 49% increase in crop yield compared to the non-amended soil). Therefore, which biochar would be the most advantageous in this system would require a cost-benefit analysis between increasing crop yield (best achieved with 2% SSBC amendments) and decreasing the PAH and PTE uptake (best achieved with 5% PNBC amendments).