School of Environmental Science and Engineering Huazhong University of Science and Technology, Wuhan, 430074, China.
PowerChina Environmental Engineering Corporation Limited, Changsha, 410000, China.
Sci Total Environ. 2022 Dec 10;851(Pt 2):158186. doi: 10.1016/j.scitotenv.2022.158186. Epub 2022 Aug 23.
Cadmium (Cd) removal from paddy soil to reduce Cd accumulation in brown rice is essential for agroecology, food safety, and human health. In this study, we demonstrate that ferric chloride (FeCl) washing combined with biochar treatment efficiently remediates Cd-contaminated paddy soil in field trials. Our results showed that 30.9 % of total Cd and 41.6 % of bioavailable Cd were removed by the addition of 0.03 M FeCl at a liquid/soil ratio of 1.5:1. The subsequent addition of 1 % biochar further reduced bioavailable Cd by 36.5 and 41.5 %, compared with FeCl washing or biochar treatment alone. The principal component regression analysis showed that the Cd content in brown rice was primarily affected by the bioavailable Cd in soil. The combined remediation contributed to the decreased Cd contents in brown rice by 45.5-62.5 %, as well as a 2.7-11.8 % increase in rice yield. The Cd contents in brown rice decreased to 0.12 and 0.04 mg kg in two cultivars of rice (Zhuliangyou189 and Zhuliangyou929), lower than the national food safety standard limit value of China (0.2 mg kg). Meanwhile, the combined remediation promoted the restoration of soil pH and organic matter as well as the improvement of available nutrients. This finding suggests that the combination of FeCl washing and biochar is an effective remediation strategy to minimize Cd bioavailability in paddy soil, and improves soil quality, thus contributing to food safety.
从稻田中去除镉以减少糙米中镉的积累对于农业生态、食品安全和人类健康至关重要。在本研究中，我们证明了氯化铁（FeCl）洗涤与生物炭处理相结合可有效地修复田间试验中受镉污染的稻田。结果表明，在液/土比为 1.5:1 的条件下，添加 0.03 M FeCl 可去除 30.9%的总镉和 41.6%的可利用镉。随后添加 1%的生物炭可使可利用镉进一步减少 36.5%和 41.5%，与单独使用 FeCl 洗涤或生物炭处理相比。主成分回归分析表明，糙米中的镉含量主要受土壤中可利用镉的影响。联合修复可使糙米中的镉含量降低 45.5-62.5%，同时使水稻产量增加 2.7-11.8%。两种水稻品种（珠梁优 189 和珠梁优 929）糙米中的镉含量分别降至 0.12 和 0.04mg/kg，低于中国国家食品安全标准限值（0.2mg/kg）。同时，联合修复促进了土壤 pH 值和有机质的恢复以及有效养分的改善。这一发现表明，FeCl 洗涤和生物炭的结合是一种有效的修复策略，可以最大限度地减少稻田中镉的生物利用度，提高土壤质量，从而保障食品安全。
