Climate change-driven droughts are deepening Bangladesh's groundwater crisis, pushing arsenic contamination to alarming levels in many districts and endangering the nation's food and health security.

A recent study detected toxic concentrations of arsenic in rice and vegetables grown in arsenic-affected regions, warning that long-term consumption could severely damage the human liver and kidneys.

Led by Prof Dr Laila Khaleda, Chair of the Department of Genetic Engineering and Biotechnology at Chittagong University, the research team included Md. Mazharul Alam, Lecturer Zarin Tasnim of Chittagong Veterinary and Animal Sciences University, Prof Dr Mohammad Al-Forkan, and several other scientists from the Bangladesh Medical University.

The study, funded by the Ministry of Science and Technology and the Bangladesh Medical Research Council, was conducted between January 2021 and January 2023 in two arsenic-contaminated upazilas of Chandpur, Hajiganj and Shahrasti.

Their findings were published on June 14, 2025 in the international journal Toxicology Reports (Elsevier).

Although previous studies in Bangladesh identified arsenic in rice, vegetables, and groundwater, this is the first research to experimentally demonstrate how contaminated food affects health.

The research revealed that arsenic levels in water, soil, and crops from the study areas far exceeded international safety limits. Groundwater samples contained up to 0.373 mg/L of arsenic, almost 30 times higher than the World Health Organization's (WHO) safe limit of 0.01 mg/L.

Soil arsenic levels reached 32.51 mg/kg, over three times the global average, while rice contained up to 0.91 mg/kg, more than double the WHO's permissible limit of 0.37 mg/kg.

Edible ferns showed the highest contamination, with arsenic concentrations reaching 1.93 mg/kg, nearly four times the safe limit.

Researchers confirmed a strong positive correlation between arsenic in irrigation water, soil, and crops, showing how contamination travels through the food chain and poses serious risks to both animals and humans.

The team conducted controlled experiments on Wistar albino rats divided into six groups, two control groups and four groups fed with arsenic-free and arsenic-contaminated rice and edible fern.

Over a 120-day period, rats that consumed contaminated food showed reduced appetite, weight loss, low hemoglobin and red blood cell counts, elevated liver enzymes, and increased kidney toxicity markers.

Histopathological examinations, led by Prof Dr Md Zillur Rahman, revealed fat accumulation, cellular damage, and necrosis in liver and kidney tissues.

"We observed distorted cells, inflammation, and signs of chronic toxicity-evidence that arsenic damages organs directly, not just through blood," Dr Rahman said.

Experts warned that arsenic, often regarded only as a groundwater contaminant, has now infiltrated Bangladesh's food chain. "This research proves that food is now a silent source of arsenic exposure," said research assistant Md. Mazharul Alam.

"Immediate actions such as ensuring arsenic-free irrigation, safe soil management, and regular food testing are essential to protect public health," he added.

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Lecturer Zarin Tasnim described the findings as "a serious warning for public health," saying that contaminated food silently introduces toxins into human bodies, particularly threatening children, women, and the elderly.

Prof Dr Mohammad Al-Forkan emphasized the national significance of the study. "This is not just an academic study, it exposes a real problem. Arsenic-contaminated irrigation water seeps into the soil, is absorbed by crops, and eventually reaches our plates. It's a direct warning about our future."

Lead researcher Prof Dr Laila Khaleda said the team's work goes beyond chemical analysis to demonstrate biological damage caused by arsenic exposure through food.

"Feeding arsenic-laden rice and vegetables for several months caused liver and kidney damage in animal models. Prolonged human exposure could lead to cancer, kidney failure, liver cirrhosis, and other chronic diseases," she said.

The researchers urged the government to establish a national monitoring system to regularly test irrigation water, soil, and food crops for arsenic contamination.

Prof Khaleda stressed, "Our findings carry an important message for the people of Bangladesh. Contaminated food causes damage at levels invisible to the naked eye but with lifelong consequences. Without immediate government action, arsenic contamination could pose a long-term national health crisis."

Experts also called for greater public awareness, routine testing of food supplies, and sustainable irrigation practices to prevent arsenic from spreading further through the food chain.

As Bangladesh continues to depend heavily on agriculture and rice remains its main crop and staple food, the researchers warn that arsenic contamination is not a localized issue. Rice grown in affected areas is distributed across the country, meaning millions could unknowingly be at risk.

"Arsenic is a silent killer," Prof Khaleda said. "If we fail to act now, we may face an invisible epidemic threatening the health of future generations."

Writer: Ridwan Ahmed, Chittagong University