title: Characterization of contaminants and evaluation of the suitability for land application of maize and sludge biochars.
abstract: Prior to the application of biochar as an agricultural improver, attention should be paid to the potential introduction of toxicants and resulting unintended impacts on the environment. In the present study, the concentrations of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and mineral elements were determined in maize and sludge biochars produced at 100 °C increments between 200 and 700 °C. The concentration ranges of total PAHs were 358-5,136 μg kg(-1) in maize biochars and 179-70,385 μg kg(-1) in sludge biochars. The total heavy metals were detected at the following concentrations (mg kg(-1)): Cu, 20.4-56.7; Zn, 59.7-133; Pb, 1.44-3.50; Cd, <0.014; Cr, 8.08-21.4; Ni, 4.38-9.82 in maize biochars and Cu, 149-202; Zn, 735-986; Pb, 54.7-74.2; Cd, 1.06-1.38; Cr, 180-247; Ni, 41.1-56.1 in sludge biochars. The total concentrations of PAHs and heavy metals in all maize biochars and most sludge biochars were below the control standards of sludge for agricultural use in China, the USA, and Europe. The leachable Mn concentrations in sludge biochars produced at below 500 °C exceeded the groundwater or drinking water standards of these countries. Overall, all the maize biochars were acceptable for land application, but sludge biochars generated at temperatures between 200 and 500 °C were unsuitable for application as soil amendments due to their potential adverse effects on soil and groundwater quality.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing, 210008, Jiangsu Province, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Luo
authors.forename: Jing
authors.initials: J
authors.lastname: Song
authors.forename: Weixia
authors.initials: W
authors.lastname: Xia
authors.forename: Mingang
authors.initials: M
authors.lastname: Dong
authors.forename: Mengfang
authors.initials: M
authors.lastname: Chen
authors.forename: Petr
authors.initials: P
authors.lastname: Soudek
mesh_terms: D000383:Agriculture; D002606:Charcoal / Q000737:chemistry*; D004777:Environment; D005308:Fertilizers / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012722:Sewage / Q000737:chemistry; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis; D013696:Temperature; D003313:Zea mays / Q000737:chemistry
chemical_list: D005308:Fertilizers; D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal