Biochar induced Pb and Cu immobilization, phytoavailability attenuation in Chinese cabbage, and improved biochemical properties in naturally co-contaminated soil
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Contamination of agricultural soils with potential toxic elements (PTEs) has caused serious health and environmental concern all over the world. Therefore, eco-friendly solutions for Pb and Cu immobilization were required to minimize their mobility through various types of biochar amendments in contaminated soil.
Materials and methods
A greenhouse pot study was conducted to evaluate the comparative effect of rapeseed residue (RP), and rice straw (RS)-derived biochars, produced at different temperatures on Pb and Cu mobility and their accumulation in a high metal accumulating crop such as Chinese cabbage (Brassica chinensis L.). Sequential extraction, leaching toxicity, and phytoavailability techniques were used to assess Pb and Cu mobility. The impacts of various types of biochars on soil surface electronegative charge and soil enzymatic activity were also investigated in contaminated soil.
Results and discussion
The sequential extraction results revealed that the application of 5% of high-temperature rice straw biochar (RS550) and rapeseed residue biochar (RP550) significantly reduced the acid-soluble fractions (active fractions) of Pb and Cu by 53.50 and 50.35% respectively. Following the addition of 5% RS550, the residual fraction (stable fractions) of Pb and Cu were increased by 36.14 and 50.94% respectively. A remarkable decrease in Pb and Cu phytoavailability and solubility was observed after the soil was treated with 5% of both RS550 and RP550 biochars. In all biochar treatments, the maximum reduction of Pb concentration in roots and shoots of the cabbage was 37.81 and 26.54%, respectively, while the concentration of Cu decreased by 50.41 and 46.25%, respectively. Incorporation of biochar into contaminated soils also improved soil urease, catalase, and acid phosphatase activities as compared to the control soil.
Biochar application greatly enhanced the Pb and Cu immobilization, reduced phytoavailability to Chinese cabbage, and improved soil enzymes activity. The significant increment in soil surface electronegative charges and soil pH after biochar incorporation was considered one of the Pb and Cu immobilization mechanisms. Overall, application of rice straw biochar produced at 550 °C could potentially be a safe, efficient, and sustainable approach to stabilize Pb and Cu and restore soil functions in contaminated soil.
KeywordsBiochar Chinese cabbage Cu Immobilization Pb Soil enzymes
This study was financially supported by the Natural Science Foundation of China (41371470), and National Sci-Tech Support Plan (2015BAD05B02).
- Ahmad M, Ok YS, Rajapakshaa AU, Lim JE, Kim B, Ahn J, Lee YH, Al-Wabel M, Lee S, Lee SS (2016) Lead and copper immobilization in a shooting range soil using soybean stover and pine needle-derived biochars: chemical, microbial and spectroscopic assessments. J Hazard Mater 301:179–186CrossRefGoogle Scholar
- American Society for Testing and Materials (ASTM) (1989) Standard methods for chemical analysis of wood charcoal, ASTM D1762–84. ASTM, PhiladelphiaGoogle Scholar
- Bashir S, Hussain Q, Akmal M, Riaz M, Hu HQ, Ijaz SS, Iqbal M, Abro S, Mehmood S, Ahmad M (2018b) Sugarcane bagasse derived biochar reduces the cadmium and chromium bioavailability to mash bean and enhances the microbial activity in contaminated soil. J Soils Sediments 18:874–886CrossRefGoogle Scholar
- Bolan NS, Naidu R, Syers JK, Tillman RW (1999) Surface charge and solute interactions in soils. Adv Agron 67:87–140. https://doi.org/10.1016/s0065-2113(08)60514-3
- Chen J, Liu X, Zheng J, Zhang B, Lu H, Chi Z, Pan G, Li L, Zheng J, Zhang X, Wang J, Yu X (2013) Biochar soil amendment increased bacterial but decreased fungal gene abundance with shifts in community structure in a slightly acid rice paddy from Southwest China. Appl Soil Ecol 71:33–44CrossRefGoogle Scholar
- Cui L, Genxing P, Lianqing L, Jinlong Y, Afeng Z, Rongjun Z, Andrew C (2013) The reduction wheat Cd uptake in contaminated soil via biochar amendments: a two to three year experiment. Bioresource 7:5666–5676Google Scholar
- Lu K, Yang X, Gielen G, Bolan N, Ok SY, Niazi KN, Xu S, Yuan G, Chen X, Zhang X, Liu D, Song Z, Liu X, Wang H (2017) Effect of bamboo and rice straw biochars on the mobility and redistribution of heavy metals (Cd, Cu, Pb and Zn) in contaminated soil. J Environ Manag 186:285–292CrossRefGoogle Scholar
- Salam A, Bashir S, Khan I, Hussain Q, Ruili G, Hu H (2018) Biochars immobilize lead and copper in naturally contaminated soil. Environ Eng Sci 35(12):1349–1360. https://doi.org/10.1089/ees.2018.0086
- Skłodowski P, Maciejewska A, Kwiatkowska J (2006). The effect of organic matter from brown coal on bioavailability of heavy metals in contaminated sioil. In: Twardowska I, Allen HE, Häggblom MM, Stefaniak S (eds) Soil and Water Pollution Monitoring, Protection and Remediation. NATO Science Series. Springer, Dordrecht, 69:299–307Google Scholar
- Soil Science Society of China (SSSC) (1999) Analysis methods for soil and agricultural chemistry. China Science and Technology Publishing House, BeijingGoogle Scholar
- USEPA (1992) Toxicity characteristic leaching procedure (TCLP), method 1311. Publication SW 846: test methods for evaluating solid waste, physical/chemical methods. Available at: www.epa.gov/sites/production/files/2015-12/documents/1311.pdf. Accessed 18 Jan 2019
- Xu GH, Zheng HY (1986) Handbook of analysis of soil microorganisms. Agriculture Press, Beijing (in Chinese)Google Scholar