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Nanoactivated Carbon Reduces Mercury Mobility and Uptake by Oryza sativa L: Mechanistic Investigation Using Spectroscopic and Microscopic Techniques
journal contribution
posted on 2020-02-20, 20:06 authored by Jianxu Wang, Sabry M. Shaheen, Christopher W.
N. Anderson, Ying Xing, Shirong Liu, Jicheng Xia, Xinbin Feng, Jörg RinklebeMercury
(Hg) contamination of paddy field poses a health risk to
rice consumers, and its remediation is a subject of global scientific
attention. In recent years focus has been given to in situ techniques
which reduce the risk of Hg entering the food chain. Here, we investigate
the use of nanoactivated carbon (NAC) as a soil amendment to minimize
Hg uptake by rice plants. Application of 1–3% NAC to soil (by
weight) reduced Hg concentration in the pore water (by 61–76%)
and its bioaccumulation in the tissues of rice plants (by 15–63%),
relative to the corresponding control. Specifically, NAC reduced the
Hg concentration of polished rice by 47–63% compared to the
control, to a level that was 29–49% lower than the food safety
value (20 ng g–1) defined by the Chinese government.
The NAC induced a change in Hg binding from organic matter to nano-HgS
in the soil as a function of soil amendment. This Hg speciation transformation
might be coupled to the reduction of sulfoxide to reduced sulfur species
(S0) by NAC. The NAC amendment may be a practical and effective
solution to mitigate the risk of Hg transferring from contaminated
soil to rice grains at locations around the world.