Beiyuan Jingzi, Awad Yasser M, Beckers Felix, Tsang Daniel C W, Ok Yong Sik, Rinklebe Jörg
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
School of Natural Resources and Environmental Science & Korea Biochar Research Center, Kangwon National University, Chuncheon 24341, Republic of Korea; Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt.
Chemosphere. 2017 Jul;178:110-118. doi: 10.1016/j.chemosphere.2017.03.022. Epub 2017 Mar 8.
Biochar has been adopted to control the mobility and phytoavailability of trace elements (TEs) in soils. To date, no attempt has been made to determine the mobility and phytoavailability of arsenic (As) and lead (Pb) in a contaminated soil with biochars as amendments under predefined redox potentials (E). Thus, in this study, a soil contaminated with As and Pb (2047 and 1677 mg kg, respectively) was pre-incubated for 105 days with three amendments (pine sawdust biomass (BM) and two biochars produced from the same feedstock at 300 °C (BC300) and 550 °C (BC550)). The aged samples were then exposed to dynamic E conditions to evaluate the mobility and phytoavailability of As and Pb after immobilization. The BM amendment significantly decreased and the BC300 slightly reduced the mobility and phytoavailability of As and Pb, which may be related to the oxygen-containing functional groups on the surface of BM and BC300. In contrast, BC550 increased the mobility of As at -300 to -100 mV and 100 mV, enhanced the phytoavailability of As under oxidizing condition (>100 mV), but reduced the phytoavailability of Pb, which might be caused by the properties of amendments and redox chemistry of the TEs. The effectiveness of BM and biochars for the stabilization of As and Pb varied under dynamic E conditions, which indicates that detailed investigations should be conducted before the applications of biochar as soil amendment under variable environmental conditions, especially for contaminated paddy soils.
生物炭已被用于控制土壤中微量元素（TEs）的迁移性和植物有效性。迄今为止，尚未有人尝试在预定义的氧化还原电位（E）下，以生物炭为改良剂来测定污染土壤中砷（As）和铅（Pb）的迁移性和植物有效性。因此，在本研究中，将一种被As和Pb污染的土壤（分别为2047和1677 mg/kg）与三种改良剂（松木锯末生物质（BM）以及由相同原料在300℃（BC300）和550℃（BC550）下制备的两种生物炭）预培养105天。然后将老化后的样品置于动态E条件下，以评估固定化后As和Pb的迁移性和植物有效性。BM改良剂显著降低了As和Pb的迁移性和植物有效性，BC300则略有降低，这可能与BM和BC300表面的含氧官能团有关。相比之下，BC550在-300至-100 mV和100 mV时增加了As的迁移性，在氧化条件（>100 mV）下提高了As的植物有效性，但降低了Pb的植物有效性，这可能是由改良剂的性质和TEs的氧化还原化学性质导致的。在动态E条件下，BM和生物炭对As和Pb的稳定效果各不相同，这表明在将生物炭作为土壤改良剂应用于多变的环境条件之前，尤其是对于污染的稻田土壤，应进行详细的研究。
