Researchers from Columbia University’s Mailman School of Public Health and the Chinese Academy of Sciences report that climate change and higher atmospheric CO2 may increase levels of toxic inorganic arsenic in paddy rice, with important public health implications. Inorganic arsenic, which forms when arsenic bonds with non‑carbon elements such as oxygen or sulphur, is more toxic than organic arsenic compounds found in seafood. Long-term exposure is linked to cancers of the lung, bladder and skin, and to heart disease and diabetes.
The team found that temperatures above two degrees together with elevated CO2 lead to higher inorganic arsenic concentrations in rice grain. Lead researcher Lewis Ziska said higher arsenic is likely caused by climate-driven changes in soil chemistry that make arsenic easier for rice plants to absorb. The study used Free-Air CO2 Enrichment and modelling and measured effects on 28 rice strains over ten years to estimate inorganic arsenic doses and health risks for seven Asian countries.
The researchers warn that because rice is a staple food in many regions, these changes could substantially raise the global burden of cancer, cardiovascular disease and other arsenic-related illness, especially in Asia by 2050. They recommend plant breeding to limit arsenic uptake, improved soil management and processing practices, and public health measures such as consumer education and exposure monitoring. External experts note that washing and careful cooking can lower arsenic in cooked rice, and that supplying mineral nutrients such as silicon, phosphorus and iron during growth can reduce plant uptake; breeders report progress on low-arsenic lines but say wider adoption will require funding.
- Bangladesh
- China
- India
- Indonesia
- Myanmar
- The Philippines
- Vietnam
Difficult words
- inorganic — Not containing carbon; opposite of organic
- toxic — Harmful or poisonous to people or animals
- staple — A main food regularly eaten by people
- burden — A heavy problem or public health load
- uptake — Absorption of a substance by a plant
- model — Make a simplified representation to study effectsmodelling
- exposure — Contact with a harmful substance over time
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could higher arsenic levels in rice affect public health and daily life in countries where rice is a staple?
- Which recommended measure (plant breeding, soil management, processing practices, or public education) do you think could be implemented most quickly, and why?
- What obstacles might prevent wider adoption of low-arsenic rice lines, and how could those obstacles be addressed?
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