Institute of Soil and Water Resources and Environmental Science, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China.
Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne Campus, Bundoora, VIC, 3086, Australia.
Environ Sci Pollut Res Int. 2018 Mar;25(9):8827-8835. doi: 10.1007/s11356-017-1148-y. Epub 2018 Jan 12.
Reducing cadmium (Cd) concentrations in rice grains is important for food safety, particularly in acid paddy fields in South China where the soils have been previously contaminated with Cd. A field experiment was conducted to evaluate the effects of four alkaline amendments, i.e., lime, compost, biochar, and carbide slag on soil bioavailability and uptake of Cd in plants of two rice cultivars (Oryza sativa L.) in a Cd-contaminated acid paddy soil. The addition of these amendments significantly decreased the concentrations of CaCl-extractable Cd by 13-41%. Cd in the acid-soluble fraction was decreased in these amended soils while it increased in the residual fraction. The amendments also decreased the uptake of Cd in the plants at the tillering and mature growth stages. The concentrations of Cd in plant tissues at maturity were in the order: root > shoot > bran > polished rice > husk. The amendment of carbide slag decreased Cd concentration in rice grains the most, followed by lime, biochar, and compost. The increases in soil pH and the decreases in the acid-soluble fraction of Cd (F1-Cd) indicated that these amendments can directly transform the highly availability fraction of Cd to a more stable fraction (residual Cd fraction) in soils. Furthermore, the Cd concentrations in polished rice grains of the two rice cultivars used were reduced by 66-67% by treatment with carbide slag. Our study suggests that carbide slag has a great potential to reduce the bioavailability and uptake of Cd in rice plants in Cd-contaminated acid paddy field soils.
降低稻米中镉（Cd）浓度对于食品安全非常重要，特别是在华南地区的酸性稻田中，这些土壤以前曾受到 Cd 污染。本田间试验旨在评估四种碱性改良剂（石灰、堆肥、生物炭和电石渣）对受 Cd 污染的酸性稻田土壤中两种水稻品种（Oryza sativa L.）植物的土壤生物有效性和 Cd 吸收的影响。添加这些改良剂可使 CaCl2 可提取 Cd 的浓度降低 13-41%。这些改良土壤中酸溶性 Cd 减少，而残渣态 Cd 增加。这些改良剂还降低了水稻分蘗期和成熟期植株对 Cd 的吸收。成熟期植物组织中 Cd 的浓度顺序为：根＞茎＞麸皮＞精米＞稻壳。钙渣改良对稻米中 Cd 浓度的降低作用最大，其次是石灰、生物炭和堆肥。土壤 pH 的升高和酸溶态 Cd（F1-Cd）的降低表明，这些改良剂可以直接将 Cd 的高生物有效性转化为更稳定的（残渣态 Cd）。此外，用电石渣处理可使两种水稻品种的精米中 Cd 浓度降低 66-67%。本研究表明，电石渣在降低受 Cd 污染酸性稻田土壤中水稻植株 Cd 的生物有效性和吸收方面具有很大的潜力。
