Learning links climate change to rising arsenic levels in paddy fields, increasing health risks

Climate change could have a major impact on arsenic levels in paddy fields, a staple food for millions of people across Asia, revealing a new study from Columbia University’s School of Postal Health. This study shows that rising temperatures above 2°C and rising carbon dioxide (CO2) levels can lead to higher concentrations of inorganic arsenic (IAS) in rice, posing a health risk for lifespan in the Asian population by 2050.

To date, the combined effects of CO2 rise and temperature on arsenic accumulation in rice have not been studied in detail. The study, conducted in collaboration with colleagues from the Johns Hopkins Bloomberg School of Public Health and the Chinese Academy of Sciences, has been featured in the Lancet Planetary Health.

“Our results suggest that this increase in arsenic levels could significantly increase the incidence of heart disease, diabetes and other non-cancer health,” said Dr. Lewis Zisca, associate professor of environmental health sciences at Columbia Mailman School.

“Because rice is a dietary staple in many parts of the world, these changes can lead to a significant increase in the global burden of cancer, cardiovascular disease, and other arsenic-related health issues.”

Ziska explained that higher arsenic levels are likely due to climate-related changes in soil chemistry that support arsenic that may be absorbed by rice grains.

“From a health perspective, the toxic effects of chronic IAS exposure are well-established, including cancer of the lungs, bladder, and skin, and ischemic heart disease. Emerging evidence suggests that arsenic exposure may be related to diabetes, the harmfulness of pregnancy, neurodevelopmental problems, and the effects of the immune system.

In fact, “intake of rice in regions such as southern China, southeastern and southeast Asia is already an important source of dietary arsenic and cancer risk,” Zisca said.

Using the Faith (free air CO2 enrichment) methodology, measuring the effects of temperature and CO2 on 28 rice strains over 10 years in the field, combined with advanced modeling techniques, the team estimated inorganic arsenic doses and health risks in seven Asian countries.

Health risks were calculated for cancer and non-cancer outcomes. Estimates of rice availability reported in the UN Food and Agricultural Organization (FAO) Food Balance Sheet were used as a starting point for estimating rice intake. Standard deviations of rice intake per body weight from US Environmental Protection Agency data were used to create normal distributions in each country.

The 2050 study’s predictions suggest a sharp increase in lifetime cancer cases, particularly lung and bladder cancers. China is projected to see the most cases with an estimated 13.4 million cancers associated with US-based arsenic exposure.

“Based on our findings, we believe there are several actions that will help reduce future arsenic exposure,” Ziska pointed out.

“These include plant breeding efforts to minimize arsenic uptake, improve soil management in rice paddies, and minimize better processing practices. Such measures, along with public health initiatives focused on consumer education and exposure monitoring, could play an important role in mitigating the health impacts of climate change.”

“Our research highlights the need for urgent action to reduce arsenic exposure in the rice, particularly as climate change continues to affect global food security,” says Ziska.