Dec 10, 2020 07:15 PM
https://eos.org/articles/will-rising-tem...-too-toxic
EXCERPTS: Rice feeds about half the world, but it is vulnerable to rising temperatures. Increased heat boosts the arsenic uptake from soil to rice plants, perhaps to toxic levels for infants. A new analysis presented at AGU’s virtual Fall Meeting 2020 revealed the root cause of this potentially poisonous transfer, providing another clue for field scientists working to address the problem.
“We found strong evidence that what’s really controlling this process is a microbially mediated reaction that takes arsenic out of the soil and [puts it] into the water,” said Yasmine Farhat, a doctoral candidate in environmental engineering at the University of Washington and lead author of the study, which appeared in Science of the Total Environment in October.
Rice is particularly vulnerable to arsenic uptake because unlike most crops, it grows in flooded conditions with anoxic soil. Microbes that thrive in these anoxic environments release arsenic into the soil’s pore water through normal metabolic reactions. Once liberated from soil particles, this pore water arsenic can be taken up by the rice plant’s roots.
[...] Results showed a strong link between rice grain arsenic concentrations and temperature and confirmed that in hotter conditions, soil pore water contained more arsenic. ... “Elevated growing temperatures may increase the risk of dietary arsenic exposure in rice systems that were previously considered low risk.”
[...] The authors suggested that real-world solutions to curtail high arsenic levels in rice should focus on restricting availability of the toxin. One approach is to let soils dry out intermittently, a method known as wetting and drying. ... In locations where arsenic availability mitigation is not feasible, cooking treatments could help.
[...] In many areas across the globe, especially the tropics, people consume rice multiple times a day. For some, alternative food staples are simply not available. A rising concentration of arsenic in rice poses a slow moving but dire threat to these communities... (MORE - details)
EXCERPTS: Rice feeds about half the world, but it is vulnerable to rising temperatures. Increased heat boosts the arsenic uptake from soil to rice plants, perhaps to toxic levels for infants. A new analysis presented at AGU’s virtual Fall Meeting 2020 revealed the root cause of this potentially poisonous transfer, providing another clue for field scientists working to address the problem.
“We found strong evidence that what’s really controlling this process is a microbially mediated reaction that takes arsenic out of the soil and [puts it] into the water,” said Yasmine Farhat, a doctoral candidate in environmental engineering at the University of Washington and lead author of the study, which appeared in Science of the Total Environment in October.
Rice is particularly vulnerable to arsenic uptake because unlike most crops, it grows in flooded conditions with anoxic soil. Microbes that thrive in these anoxic environments release arsenic into the soil’s pore water through normal metabolic reactions. Once liberated from soil particles, this pore water arsenic can be taken up by the rice plant’s roots.
[...] Results showed a strong link between rice grain arsenic concentrations and temperature and confirmed that in hotter conditions, soil pore water contained more arsenic. ... “Elevated growing temperatures may increase the risk of dietary arsenic exposure in rice systems that were previously considered low risk.”
[...] The authors suggested that real-world solutions to curtail high arsenic levels in rice should focus on restricting availability of the toxin. One approach is to let soils dry out intermittently, a method known as wetting and drying. ... In locations where arsenic availability mitigation is not feasible, cooking treatments could help.
[...] In many areas across the globe, especially the tropics, people consume rice multiple times a day. For some, alternative food staples are simply not available. A rising concentration of arsenic in rice poses a slow moving but dire threat to these communities... (MORE - details)
