Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam.
Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam; Hanoi University of Natural Resources & Environment, 41A Phu Dien, Bac Tu Liem, Hanoi, Viet Nam.
J Environ Manage. 2022 Feb 15;304:114294. doi: 10.1016/j.jenvman.2021.114294. Epub 2021 Dec 15.
On-site open burning is a common practice for handling rice straw, but its negative impacts, e.g., biomass loss and air pollution, are largely debated worldwide. To address the negative effects of open burning, many efforts have been made to 'ignite' worldwide bans. However, these bans are likely based on a singular view in which some positive aspects of open burning are overlooked. In this study, we aimed to determine the thermal-induced changes of straw and straw arsenic (As) under open burning and heat-treatments (in the temperature range from 300 to 900 °C). It was found that silica phase in rice straw (so-called phytolith) can encapsulate As in its structure. Open burning or heat-treatment of straw resulted in a tighter association of As and phytolith, thereby reducing dissolution of As. We proposed an opinion that open burning causes air pollution, but it can increase the activity of phytolith in sequestrating As, enabling delayed As cycle in rice ecosystems. The combat of on-site open burning of rice straw to reduce air pollution will alter straw handling routines, thereby changing the cycle of straw phytolith and the route of straw As.
现场露天燃烧是处理稻草的一种常见做法，但它的负面影响，如生物质损失和空气污染，在世界范围内引起了广泛的争论。为了解决露天燃烧的负面影响，全世界许多人都在努力推动全面禁止露天燃烧。然而，这些禁令可能基于一种单一的观点，即忽视了露天燃烧的某些积极方面。在这项研究中，我们旨在确定稻草和稻草砷（As）在露天燃烧和热处理（温度范围从 300 到 900°C）下的热诱导变化。结果发现，稻草中的硅质相（所谓的植硅体）可以将 As 包裹在其结构中。稻草的露天燃烧或热处理导致 As 与植硅体的结合更加紧密，从而减少了 As 的溶解。我们提出了一种观点，即露天燃烧会造成空气污染，但它可以增加植硅体固定 As 的活性，从而使水稻生态系统中的 As 循环延迟。为了减少空气污染而禁止现场露天燃烧稻草，将会改变稻草处理的常规做法，从而改变稻草植硅体的循环和稻草 As 的路径。
