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Climate Change Will Make Rice Toxic, Say Researchers (arstechnica.com) 90

Rice, the world's most consumed grain, will become increasingly toxic as the atmosphere heats and as carbon dioxide emissions rise, potentially putting billions of people at risk of cancers and other diseases, according to new research published this week in The Lancet. From a report: Eaten every day by billions of people and grown across the globe, rice is arguably the planet's most important staple crop, with half the world's population relying on it for the majority of its food needs, especially in developing countries.

But the way rice is grown -- mostly submerged in paddies -- and its highly porous texture mean it can absorb unusually high levels of arsenic, a potent carcinogenic toxin that is especially dangerous for babies.
After growing rice in controlled fields for six years, researchers from Columbia University and international partners found that when both temperature and CO2 increased in line with climate projections, arsenic levels in rice grains rose significantly. "When we put both of them together, then wow, that was really something we were not expecting," said Lewis Ziska, a plant physiologist at Columbia University who led the study. "You're looking at a crop staple that's consumed by a billion people every day, and any effect on toxicity is going to have a pretty damn large effect."

Inorganic arsenic exposure has been linked to cancers, heart disease, and neurological problems in infants. Disease risk rose across all seven top rice-consuming Asian countries analyzed. "This is one more reason to intervene -- to control people's exposure," said co-author Keeve Nachman of Johns Hopkins University. "The No. 1 thing we can do is everything in our power to slow climate change."

Climate Change Will Make Rice Toxic, Say Researchers

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  • Rice bran contains six times the amount of arsenic as the rice. It's not a "solution," but not regularly eating brown rice or using rice bran in nutritional supplements is going alleviate the larger part of the problem.

    • by Tablizer ( 95088 )

      Too bad because rice bran has a lot of nutritional value.

    • It's more complicated than that. The arsenic in the bran apparently isn't as bioavailable as the arsenic in the endosperm, and so while brown rice does have more arsenic it's not as much of a difference as you'd think. Also there's just a lot less bran than endosperm. I read a thing which claimed that brown rice has anywhere from 30-70% more arsenic in practice, compared to white rice. The variety of rice and location where it was grown also matter a lot. Here. [consumerreports.org]
  • It's clearly a conspiracy to kill off all the Asians

  • Is it higher water temperatures, more acidic water, or something else that is causing it, and is it leaching more arsenic from the rock and soil, or is it just higher concentrations due to water re-use and evaporation?

    • by dstwins ( 167742 ) on Friday April 18, 2025 @01:28PM (#65315257) Homepage
      Arsenic is pretty common in most rocks and soils. But cooler temps keeps it "locked" away so its a very slow leeching poison.. but as you heat it up, that process speeds up and dumps a LOT more into the surrounding water where rice paddies are growing.

      Think of it this way.

      Get some rock salt (like big crystal salts).

      get cold water and drop some in there.. It will dissolve slowly
      then
      get warm water and drop some in there, it will dissolve quicker and more diffuse in the water (if you taste the water, it will taste saltier quicker).

      And that's basically what;s going on..

      And its the same for just about all toxic chemicals (toxic to humans) in rocks and soil.. as the ambient temp rises, it speeds up the erosion of those rocks and chemicals contained in soils..
  • The US is perfectly capable of growing rice. Im asian, ive tried MO grown jasmine rice, its not grown in the tropics, and it taste dam good. See tariff dispute on US grown rice.
    • If you think growing your own rice will make America great (again?) who am I to argue.
    • And you think there's no arsenic present in the rocks and soil in the US?

      Why would rice grown in the US be any less susceptible to the mechanics of what is happening here?

    • by Hodr ( 219920 )

      And most Asian countries can grow rice without using flooded paddies. It may be the cheapest/easiest method, but certainly not the only method.

    • by shoor ( 33382 )

      Some of us Americans care about suffering even among people who aren't American, even the billions of non-Americans who are living in developing countries whose children may grow up shy of their intellectual potential.

  • by Dru Nemeton ( 4964417 ) on Friday April 18, 2025 @01:56PM (#65315345)
    If you pre-boil any rice in water first, then drain and cook normally, you can remove a significant amount of toxins in the grain: New way of cooking rice removes arsenic and retains mineral nutrients, study show [sheffield.ac.uk]
    • Edit: "...then drain, RINSE, and cook..."
    • I expect that Japanese rice cookers will soon have water and drain lines, kind of like an RO system, to handle the draining, rinsing, and refilling as part of the new cooking process.

    • by Anonymous Coward
      That also removes the healthy water soluble vitamins and minerals.
  • (Quotes from Google Gemini)

    Higher temperatures can increase arsenic levels in rice primarily due to changes in soil chemistry and increased arsenic availability. Warmer temperatures can boost arsenic mobilization from the soil into the water, which is then taken up by the rice plants, leading to higher arsenic concentrations in the grain. Additionally, warmer temperatures can affect the soil microbiome, potentially favoring arsenic-loving bacteria that increase the availability of arsenic in the soil.

    This is interesting... maybe genetic engineering can help?

    While warmer temperatures can increase arsenic uptake, rice plants also have a mechanism to protect themselves. Increased arsenic exposure can trigger the expression of a gene called OsABCC1, which helps the plant move arsenic out of the grain, potentially reducing the amount in the edible part of the rice.

  • by jamienk ( 62492 ) on Friday April 18, 2025 @05:15PM (#65315809)

    Lundberg conducts regular arsenic testing and publish results. Whole Foods' 365 brown rice has higher levels than other brands. Rice from California, India, and Pakistan mostly has lower levels than from southern US states like Arkansas, Louisiana, and Texas. I assume this means that you can mitigate the arsenic. It seems like there are various approaches, some better and more thoughtful than others.

    https://nutritionfacts.org/vid... [nutritionfacts.org]

  • We should look into genetically engineering strains of rice to absorb less arsenic.

    Obviously we should also stop emitting CO2, but even if we were net zero today, CO2 levels would take a long time to decrease, and temperatures would continue rising for a while. And obviously it's going to take some time to get to net zero, so we need to think about mitigating the damage, not focus solely on emissions reduction.

  • Rice, especially brown rice, should be parboiled (for five minutes in pre-heated water, which is then discarded) to remove arsenic. Though it doesn't remove it all, and parboiling also removes some vitamins, so the discovery in thi article is still a problem.

    https://www.sheffield.ac.uk/su... [sheffield.ac.uk]

  • I asked ChatGPT4o to summarize:

    Measured Arsenic Levels in Rice Samples (from the study):

    Under current climate conditions, the average concentration of inorganic arsenic in rice grains was about 0.15 mg/kg (150 ppb).
    Under simulated mid-century climate conditions (higher temperature and COâ), it increased to 0.225 mg/kg (225 ppb), a 50% rise.

    ---

    Current Regulatory Standards for Inorganic Arsenic in Rice:

    U.S. FDA:

    Infant rice cereals: max 100 ppb

    No federal limit for general rice consumption

    European Union:

    Wh

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