Harmful heavy metals found in potato tubers: Study

A recent study by Bangladesh Agriculture University (BAU) researchers identified harmful heavy metals like nickel and cadmium in potato tubers and potato-growing soil, raising public health concerns about potential risks, including cancer.

The study revealed that these metals are possibly entering potatoes through various avenues such as industrial waste, irrigation water, fertilisers, and pesticides, contaminating the soil and subsequently the crops.

The study report, published by Dutch academic publisher Elsevier recently, raised public health concerns as potatoes are a staple food for many Bangladeshis.

Public health experts raised concerns due to the presence of these harmful heavy metals in such a widely consumed crop. These metals can pose health risks including cancer if consumed in excess.

They also highlighted the potential for these metals to disrupt digestion, damage kidneys, and livers, and contribute to infertility.

In the study, scientists have identified the presence of a maximum of 2.938 micrograms of nickel and 0.0139 micrograms of cadmium per gram of potato. These two metals are harmful to human health even in small amounts. 

Researchers collected potatoes and soil samples from potato fields in Muktagacha, Ishwarganj, Phulpur, and Gafargaon areas in the Mymensingh district and researched levels of nine metals like cadmium, nickel, lead, chromium, copper, zinc, iron, cobalt, and manganese.

Additionally, scientists did not find the presence of lead, chromium, and cobalt in potatoes.

According to the Bangladesh Bureau of Statistics (BBS) household income survey 2022 data, an average person consumes 69.7 grams of potato per day.

In this context, people have to consume 0.0913 mg of nickel and 0.0005 mg of cadmium from potatoes every day.

According to the study, among the soil samples used for potato production, researchers found 4.69-19.92 micrograms of lead, 21.27-99.84 micrograms of nickel, 0.04-0.32 micrograms of cadmium, 2.01-10.60 micrograms of cobalt, 44.79-88.61 micrograms chromium, 11.94-30.03 micrograms copper, 53.20-70.42 micrograms zinc, 14541-41,153 micrograms iron, and 562-782.2 micrograms manganese in per gram of soil. That means, the soil also has excessive lead, nickel, and cadmium.

Md Zakir Hossen, Professor of the Department of Agricultural Chemistry of BAU, and spokesperson of the research team told TBS that these heavy metals can be added to crops usually through industrial waste on land. Therefore, the team has selected the place where there are no factories for the research.

"The presence of nickel and cadmium found in soil and potatoes is a cause for concern. These heavy metals can enter crops through groundwater or river water used for irrigation, fertilisers, and pesticides," he said.

He emphasised the need for policy-level action to ensure safe food production and protect public health from heavy metal contamination.

Public health expert Dr Lenin Chowdhury told TBS that these heavy metals mix with food disrupt digestion in the human body and damage the kidneys and liver by mixing with the blood.

He highlighted the impact on fertility rates and the increasing incidence of cancer and kidney diseases in Bangladesh, attributing these health issues partially to heavy metal exposure from food sources like rice and now potatoes.

"About two and a half to three lakh people are newly diagnosed with cancer every year. About 10% of adults suffer from kidney disease. The rate of infertility is increasing day by day," he added.

While talking to TBS, Badal Chandra Biswas, director general of the Department of Agriculture Extension, acknowledged a lack of awareness regarding fertiliser and pesticide use among farmers.

"We always encourage them to use balanced fertilisers and pesticides," he added.

According to the Department of Agriculture Extension data, the country has produced about 1.09 crore tonnes of potatoes in the current financial year.