Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China.
Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China.
Environ Sci Pollut Res Int. 2018 Jun;25(17):16991-17001. doi: 10.1007/s11356-018-1874-9. Epub 2018 Apr 7.
Biochar has high potential for organic pollutant immobilization due to its powerful sorption capacity. Nevertheless, potential risks may exist when biochar-sorbed organic pollutants are bioavailable. A direct plant exposure assay in combination with an organic solvent extraction experiment was carried out in this study to investigate the bioavailability of polycyclic aromatic hydrocarbons (PAHs) with the application of pine needle biochars pyrolyzed under different temperatures (100, 300, 400, and 700 °C; referred as P100-P700 accordingly). Biochar reduced solvent extractability and plant uptake of PAHs including naphthalene (Naph), acenaphthene (Acen), phenanthrene (Phen), and pyrene (Pyr), especially for three- and four-ring PAHs (Phen and Pyr) with high-temperature biochar. Plant uptake assay validates with organic solvent extraction for bioavailability assessment. Sorption of PAHs to biochars reduced plant uptake of PAHs in roots and shoots by lowering freely dissolved PAHs. Aging process reduced the bioavailability of PAHs that were bound to biochar. High pyrolysis temperature can be recommended for biochar preparation for purpose of effectively immobilizing PAHs, whereas application of moderate-temperature biochar for PAH immobilization should concern the potential risks of desorption and bioavailability of PAHs.
生物炭由于其强大的吸附能力，对有机污染物的固定具有很高的潜力。然而，当生物炭吸附的有机污染物具有生物可利用性时，可能存在潜在风险。本研究采用直接植物暴露试验和有机溶剂萃取实验，研究了不同温度（100、300、400 和 700°C；分别称为 P100-P700）下热解的松针生物炭对多环芳烃（PAHs）的生物利用性。生物炭降低了萘（Naph）、苊（Acen）、菲（Phen）和芘（Pyr）等 PAHs 的溶剂可提取性和植物吸收，特别是对高环 PAHs（Phen 和 Pyr）。植物吸收试验通过有机溶剂萃取验证了生物利用性评估。PAHs 对生物炭的吸附降低了根系和地上部分自由溶解 PAHs 的植物吸收。老化过程降低了与生物炭结合的 PAHs 的生物利用性。为了有效固定 PAHs，推荐使用高温热解生物炭制备生物炭，而应用中温生物炭固定 PAHs 时应考虑 PAHs 解吸和生物利用性的潜在风险。
