Climate Change May Increase Toxic Arsenic Levels in Rice, Study Warns

Rice, which is consumed daily by a large portion of the global population, particularly in developing countries, provides a primary source of nutrition for nearly half of humanity. However, scientists now warn that rising temperatures and increasing carbon dioxide levels could elevate concentrations of arsenic in the crop.

Rising temperatures linked to increased toxicity

The study, published in The Lancet Planetary Health, found that when both atmospheric carbon dioxide and temperatures rise—conditions expected under ongoing climate change—the levels of arsenic, particularly its more harmful inorganic form, also increase in rice grains.

Researchers conducted a six-year experiment in controlled agricultural settings, exposing multiple rice varieties to projected future climate conditions. The results showed a clear and concerning trend: higher environmental temperatures combined with elevated CO2 significantly boosted arsenic accumulation in rice.

Why rice is especially vulnerable

Rice is uniquely susceptible to arsenic contamination due to the way it is cultivated. It is typically grown in flooded paddies, allowing it to absorb large amounts of water—and any substances dissolved in it, including arsenic.

Arsenic exists naturally in soil and water, but inorganic arsenic—commonly associated with industrial pollution—poses the greatest health risk. The study highlights that climate-driven changes in soil chemistry can further increase the availability of this toxic form.

Serious health implications

Exposure to inorganic arsenic has been linked to a range of serious health conditions, including cancers of the skin, lungs and bladder, cardiovascular disease, and developmental problems in infants.

Using consumption data from major rice-eating nations such as China, India, Indonesia and Bangladesh, researchers projected that rising arsenic levels could increase disease risks across these populations.

Call for action and adaptation

Scientists say the findings should prompt regulators to reconsider safety thresholds for arsenic in food, particularly given the absence of strict limits in some countries. They also suggest developing rice varieties that absorb less arsenic and encouraging dietary diversification as potential solutions.

Experts emphasise that while mitigation strategies can reduce exposure, addressing the root cause—climate change—remains critical. Without action to limit global warming, the risks associated with toxic food contamination are expected to grow.