Climate Change Raises Arsenic in Rice and Cancer Risks

A new study published in The Lancet Planetary Health journal warns that climate change may be exacerbating arsenic levels in rice, thus increasing long-term cancer and health risks for populations in Asian countries by 2050. Researchers from Columbia University in the United States have found that an increase in global temperatures exceeding 2 degrees Celsius, along with rising carbon dioxide levels, may alter soil chemistry in a way that favors arsenic absorption by rice grains. Both contaminated soil and water used for irrigation are known to elevate inorganic arsenic levels in rice, and cooking with arsenic-laden water further exacerbates the problem. Heightened arsenic exposure is associated with an increased risk of lung, bladder, and skin cancers, among others. "Our findings indicate that rising arsenic levels could significantly escalate the incidence of heart disease, diabetes, and other non-cancerous health effects," said Lewis Ziska, associate professor of environmental health sciences at Columbia University. Ziska emphasized that, "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." The study highlights rice consumption as a major health concern in South and Southeast Asia—regions including India, Bangladesh, Nepal, Thailand, and Vietnam, where rice is essential to daily diets. The combined effects of increasing CO2 and temperatures on arsenic levels in rice were not thoroughly investigated until this study. Conducted over a decade, the research evaluated 28 varieties of rice under these changing conditions. Using sophisticated models, the researchers estimated inorganic arsenic doses and associated health risks for seven Asian countries: Bangladesh, China, India, Indonesia, Myanmar, the Philippines, and Vietnam. The study found that rising temperatures and CO2 levels interact synergistically to increase arsenic concentrations in rice, predicting cancer cases in the tens of millions across Asian countries by 2050. The risk of bladder and lung cancers is projected to rise in direct proportion to arsenic exposure, with a 44% increase in risk anticipated under worsening climate conditions. China, in particular, may face 13.4 million cancer cases attributable to arsenic in rice by mid-century. Beyond cancer, arsenic exposure is increasingly linked to other serious health issues, including diabetes, adverse pregnancy outcomes, neurodevelopmental challenges, and immune system effects. The study's authors advocated for measures to mitigate arsenic exposure, such as breeding rice strains that absorb less arsenic, improving soil management practices in rice paddies, and launching public health initiatives.