期刊
ENVIRONMENTAL POLLUTION
卷 224, 期 -, 页码 136-147出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.envpol.2017.01.072
关键词
Arsenic bioavailability; Soil amendments; Fe fractions; Arsenic fractionation; Fe plaques
资金
- National Natural Science Foundation of China [41671472, 41330857, 41501550, 41201517]
- NSFC-Guangdong Joint Fund [U1401234]
- Pearl River S&T Nova Program of Guangzhou [201506010053]
- National Key Research and Development Program of China [2016YFD0800700]
- Guangzhou Key Laboratory of Environmental Exposure and Health [GZKLEEH201604]
- National Key Technology R&D Program of China [2015BAD05B05]
Iron (Fe)-based solids can reduce arsenic (As) mobility and bioavailability in soils, which has been well recognized. However, to our knowledge, there are few studies on As uptake at different growth stages of rice under Fe compound amendments. In addition, the formation of Fe plaques at different growth stages of rice has also been rarely reported. Therefore, the present study was undertaken to investigate As mobility and bioavailability in paddy soil under Fe compound amendments throughout the whole growth stage of rice plants. Amendments of poorly crystalline Fe oxides (PC-Fe), FeCl2+NaNO3 and FeCl2 reduced grain As by 54% +/- 3.0%, 52% +/- 3.0% and 46% +/- 17%, respectively, compared with that of the non amended control. The filling stage was suggested to be the key stage to take measures to reduce As uptake. At this stage, all soil amendments significantly reduced As accumulation in rice plants. At the maturation stage, PC-Fe amendment significantly reduced mobile pools and increased immobile pools of soil As. Besides, PC-Fe treatment promoted the transformation of Fe fractions from dissolved Fe to adsorbed, poorly crystalline and free Fe oxides. Moreover, significant positive correlations between soil Fe fractions and As fractions were found. Accordingly, we hypothesized that Fe compound amendments might affect the concentration distribution of Fe fractions first and then affect As fractionation in soil and its bioavailability to rice plants indirectly. The formation of Fe plaques varied with growth stages and different treatments. Significantly negative correlations between mobile pools of As and Fe or As in Fe plaques indicated that Fe plaques could immobilize mobile As in soils and thus affect As bioavailability. Overall, the effect of the soil amendments on reduction of As uptake varied with growth stages and different treatments, and further research on the key stage for reducing As uptake is still required. (C) 2017 Elsevier Ltd. All rights reserved.
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