article · Environmental Science & Technology
Mercury contamination in rice paddy fields poses a critical risk to consumers when the metal enters the food chain. Applying nanoactivated carbon as an in situ soil amendment offers a potential method to restrict this uptake. Adding between one and three percent nanoactivated carbon by weight to soil reduced mercury concentrations in pore water by 61 to 76 percent. Consequently, mercury bioaccumulation across rice plant tissues declined by 15 to 63 percent compared to untreated controls. In polished rice grains, mercury concentrations dropped by 47 to 63 percent, bringing levels 29 to 49 percent below the Chinese regulatory food safety threshold of 20 nanograms per gram. The material induced a chemical shift, causing mercury to bind as nanoscale mercury sulfide rather than with organic matter, potentially driven by the reduction of sulfoxide to reduced sulfur species.
Mercury accumulation in staple crops like rice threatens human health across contaminated agricultural regions. Finding effective treatments to immobilise toxic heavy metals directly within the soil allows farming to continue safely. Demonstrating that a soil amendment can drop mercury levels in polished rice far below established safety thresholds provides a clear route to protecting the food supply from toxic contamination.
This approach could enable agricultural remediation products for rice growers and environmental agencies managing mercury-polluted paddy fields. Applied at one to three percent soil weight, nanoactivated carbon demonstrates clear efficacy in reducing grain contamination below regulatory limits. The work reflects applied and tested research in a soil-plant system, though the abstract does not indicate whether larger field-scale deployment or production economics have been evaluated.
AI-generated from the published abstract. Always read the original work before citing.
Mercury (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<sup>-1</sup>) 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 (S<sup>0</sup>) 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.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.1021/acs.est.9b05685
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
