Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou 510650, China.
Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science and Technology, Guangzhou 510650, China.
Sci Total Environ. 2019 Feb 1;649:535-543. doi: 10.1016/j.scitotenv.2018.08.387. Epub 2018 Aug 28.
Organic matter (OM) plays an important role in the mobility of heavy metal(loid)s. Peat containing abundant OM can be used as an organic fertilizer improving physical and chemical properties of soil. Previous studies indicated that the immobilization of heavy metal(loid)s by peat is affected by the presence of metal oxides and/or hydroxides and that Fe-enriched peat is very effective in immobilizing metal(loid)s. Accordingly, we hypothesize that simultaneous application of peat and Fe-containing compounds may pronouncedly immobilize heavy metal(loid)s. In this study, the effects of the combined applications of woody peat and Fe(NO) on As and Cd mobilities and accumulations in rice during the whole growth period were investigated by a pot experiment. The combined applications of woody peat and Fe(NO) significantly decreased As(III) and Cd in porewater due to pH increases induced by applications of Fe(NO), and these decreases were enhanced with increasing Fe(NO). In addition, simultaneous application of peat and Fe(NO) significantly decreased mobile portions of As and Cd but significantly increased their immobile portions. Increasing Fe(NO) increased the amount of As immobilized by poorly crystalline Fe oxides. The formation of Fe plaques and production of poorly crystalline Fe oxides were enhanced by Fe(NO) addition, which also contributed to the immobilization of As and Cd in soil. Overall, the combined applications of woody peat and Fe(NO) provided a strategy for simultaneously immobilizing As and Cd in soils and further alleviating their accumulations from soil to rice plants. In paddy soil, the frequent occurrence of iron redox activity due to the alternating wetting and drying cycles provided favorable conditions for interactions between Fe and OM, and this process and its associated metal(loid) immobilization may be more important than we thought and need further study.
有机物质（OM）在重金属（loid）的迁移中起着重要作用。富含 OM 的泥炭可用作有机肥，改善土壤的物理和化学性质。先前的研究表明，泥炭对重金属（loid）的固定受金属氧化物和/或氢氧化物的存在影响，富铁泥炭在固定金属（loid）方面非常有效。因此，我们假设同时施用泥炭和含铁化合物可能会显著固定重金属（loid）。在这项研究中，通过盆栽实验研究了木质泥炭和 Fe(NO)同时施用对水稻整个生长期间 As 和 Cd 迁移和积累的影响。由于施用 Fe(NO)导致 pH 值升高，木质泥炭和 Fe(NO)的同时施用显著降低了孔水中的 As(III)和 Cd，并且这种降低随着 Fe(NO)的增加而增强。此外，泥炭和 Fe(NO)的同时施用显著降低了 As 和 Cd 的可移动部分，但显著增加了它们的不可移动部分。增加 Fe(NO)增加了由非晶态 Fe 氧化物固定的 As 量。Fe(NO)的添加增强了 Fe 斑块的形成和非晶态 Fe 氧化物的产生，这也有助于土壤中 As 和 Cd 的固定。总的来说，木质泥炭和 Fe(NO)的同时施用为同时固定土壤中的 As 和 Cd 并进一步减轻它们从土壤向水稻植株的积累提供了一种策略。在稻田土壤中，由于干湿交替循环导致的铁氧化还原活性的频繁发生为 Fe 和 OM 之间的相互作用提供了有利条件，这个过程及其相关的金属（loid）固定可能比我们想象的更重要，需要进一步研究。
