Rice is grown in flooded paddies, where low-oxygen conditions release arsenic from soil or groundwater. The plant absorbs this arsenic through the same channels it uses to take in nutrients
Published Apr 24, 2025 | 7:00 AM ⚊ Updated May 24, 2025 | 7:40 PM
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Synopsis: A 10-year study published in The Lancet Planetary Health reveals that rising temperatures and CO₂ levels are increasing inorganic arsenic absorption in rice. This toxic element is linked to cancer, heart disease, and developmental issues. The findings raise major health concerns for India and Asia, where rice is a staple. The study was conducted in China’s Yangtze River Delta
In India, rice is more than food—it’s tradition, livelihood, and the backbone of millions of meals. But a new study has raised serious concerns: Climate change could be making our rice more poisonous.
A 10-year field study published in The Lancet Planetary Health has found that rising temperatures and carbon dioxide (CO₂) levels are causing rice to absorb more inorganic arsenic—a harmful element known to cause cancer, heart disease, and developmental issues. For India, where rice is a staple for over half the population, this finding carries major health implications.
The study shows that as global temperatures rise and carbon dioxide (CO₂) levels climb, paddy rice is absorbing more inorganic arsenic—a toxic substance linked to cancer, heart disease, and developmental problems.
And that’s deeply concerning for Asia, where rice is not just food, but culture, tradition, and daily sustenance.
Researchers from China’s top agricultural institutes and Johns Hopkins University conducted real-world experiments across ten years (2014–2023) in the Yangtze River Delta—a prime rice-growing region in China. They simulated future climate conditions with higher CO₂ (by 200 ppm) and temperatures (+2°C) to see how rice plants respond.
The result? A clear increase in the amount of inorganic arsenic in rice grains—especially when CO₂ and temperature rose together. In other words, climate change could make the rice we eat more toxic.
“Our results suggest that this increase in arsenic levels could significantly elevate the incidence of heart disease, diabetes, and other non-cancer health effects,” said Lewis Ziska, PhD, Columbia Mailman School associate professor of Environmental Health Sciences said in a statement. “As rice is a dietary staple in many parts of the world, these changes could lead to a substantial rise in the global burden of cancer, cardiovascular diseases, and other arsenic-related health issues.”
Arsenic is a naturally occurring element found in the Earth’s crust. It seeps into soil and water from rocks and minerals over time. But just because it’s natural doesn’t mean it’s safe—especially in the form that gets into rice.
There are two main types of arsenic:
And here’s the troubling part from the study: rice soaks up more inorganic arsenic than almost any other food crop.
Rice is usually grown in flooded fields, or paddies. These waterlogged conditions create low-oxygen environments that make it easier for arsenic trapped in soil or groundwater to be released into the water around the plant roots. The rice plant then absorbs this arsenic through the same pathways it uses to take in nutrients like silicon.
That arsenic travels from the roots to the grain, where it can stay—even after the rice is milled or cooked.
One key finding: A gene in soil bacteria (arsC), which helps convert arsenic into its more absorbable form, was six times more active under future climate conditions.
Over time, eating even small amounts of inorganic arsenic can add up. It doesn’t cause immediate symptoms like food poisoning, but rather builds up slowly in the body, causing serious health problems down the line. The major risks include:
And since rice is a daily staple in countries like India, people may be unknowingly ingesting arsenic every single day—not just once in a while.
“From a health perspective, the toxicological effects of chronic arsenic exposure are well established and include cancers of the lung, bladder, and skin, as well as ischemic heart disease. Emerging evidence also suggests that arsenic exposure may be linked to diabetes, adverse pregnancy outcomes, neurodevelopmental issues, and immune system effects. In fact, “ingesting rice in regions like southern China and Southeast and South Asia is already a significant source of dietary arsenic and cancer risk,” said Ziska.
There’s no completely “safe” level of arsenic, especially for young children, pregnant women, and those who eat rice frequently. That’s why some countries and international agencies have proposed safety limits. For example:
The European Union has set a maximum limit of 100 parts per billion (ppb) of inorganic arsenic in rice for infants.
The U.S. FDA has recommended the same for infant rice cereal, but it’s not a legally enforceable standard.
India currently does not have formal limits for arsenic in rice—though this study may push regulators to rethink that.
The researchers modeled arsenic exposure in seven major rice-consuming countries: India, China, Bangladesh, Vietnam, Myanmar, Indonesia, and the Philippines. Using population data for the year 2050, they predicted the health impact.
Under future climate conditions (higher CO₂ and temperature), arsenic exposure from rice could lead to:
For example, in Vietnam, projected arsenic exposure levels could rise by 44%—pushing average intake well beyond safety thresholds.
In numbers: The average daily exposure to inorganic arsenic in India is currently estimated at 1.54 micrograms per kilogram of body weight. Under a hotter, CO₂-rich climate, this could increase to 2.21 micrograms—a level linked with elevated health risks, especially for vulnerable populations like pregnant women and children.
Recent data from 2023–24 on cereal consumption patterns reinforces this reality, showing that rice continues to dominate diets across the five southern states of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, and Telangana.
In rural areas, rice accounts for an overwhelming share of total cereal intake. People in Telangana consume an average of 10.18 kg of cereals per month, of which a staggering 91.35 percent is rice.
The figure is nearly as high in Andhra Pradesh, where 91.78 percent of cereals consumed are rice. Tamil Nadu and Kerala show similar trends, with rice contributing over 90 percent and 87 percent respectively to total rural cereal intake. Even in Karnataka, where traditional diets include a higher share of millets, rice still makes up over 64 percent of rural cereal consumption.
Urban areas, too, follow the same pattern. In Hyderabad, Chennai, Kochi, and Bengaluru, rice continues to be the preferred grain, contributing between 66 to 90 percent of monthly per capita cereal intake. Urban households in Andhra Pradesh, for example, still consume 90.32 percent of their cereals in the form of rice, while Telangana follows closely with 87.02 percent. These numbers reflect not just a dietary preference, but a deeply rooted cultural and agricultural connection to rice.
In southern states, where rice is eaten two or three times a day, often from the same local agricultural sources, the cumulative exposure to arsenic could be dangerously high in the coming decades. Vulnerable groups such as infants and pregnant women could be particularly at risk.
The study also points to solutions. They suggest:
“Based on our findings, we believe there are several actions that could help reduce arsenic exposure in the future,” Ziska noted. “These include efforts in plant breeding to minimize arsenic uptake, improved soil management in rice paddies, and better processing practices. Such measures, along with public health initiatives focused on consumer education and exposure monitoring, could play a critical role in mitigating the health impacts of climate change on rice consumption.
(Edited by Ananya Rao)
