Rajshahi, Dec 31 (V7N) — Researchers from the Bangladesh Council of Scientific and Industrial Research (BCSIR), the Technology Transfer and Innovation Institute, and the University of Rajshahi have identified unsafe concentrations of six common anions—fluoride, chloride, nitrite, nitrate, phosphate, and sulfate—in fruits and vegetables collected from Rajshahi markets. The study, published last week in the peer-reviewed journal Food Chemistry Advances, focused primarily on nitrate, nitrite, and phosphate contamination.

Using ion chromatography techniques, the researchers found that several samples exceeded the safe limits set by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO). Leafy vegetables, including spinach and lettuce, showed the highest concentrations of the six anions, attributed to excessive use of nitrogen-based fertilizers in intensive farming practices.

Comparative analysis revealed that fluoride levels in Rajshahi vegetables were significantly higher than similar studies in India, Morocco, and West Bengal. Certain vegetables, such as radish and bitter gourd, contained elevated nitrate levels, while papaya showed the highest nitrate concentration among fruits. Overall nitrate levels were comparable to, or higher than, those reported in Sylhet, China, and parts of Nigeria.

High levels of phosphate and sulfate were also detected, especially in banana, red leaf vegetables, and spinach. Chloride was present in all samples, with the highest levels found in dates and spinach.

The study emphasized that rapid increases in fertilizer use over recent years have not been matched by adequate training in balanced nutrient management or residue control. As a result, excessive nitrate accumulates in edible plant tissues, entering the food chain and posing health risks. Children are particularly vulnerable due to higher intake relative to body weight.

Shankar K. Biswas, a physician at Rajshahi Medical College Hospital, noted that nitrate and nitrite can form carcinogenic nitrosamines in the human body, while prolonged exposure to high fluoride, phosphate, and sulfate levels may contribute to kidney, cardiovascular, and gastrointestinal complications.

The study also highlighted the lack of a coordinated national surveillance system for chemical residues in food, noting that current testing remains sporadic and largely confined to academic research. Ashraful Islam, a BCSIR scientific officer involved in the research, stated that fragmented responsibilities among multiple agencies weaken accountability and enforcement. Laboratory capabilities at district and sub-district levels are limited, and mandatory testing prior to market entry is virtually absent.

The researchers called for strict regulation of nitrogen fertilizer use, farmer training in balanced nutrient management, and regular food testing using modern analytical methods. They also recommended setting maximum residue limits for nitrates aligned with international standards and improving coordination among the Bangladesh Food Safety Authority, Department of Agricultural Extension, and public health agencies.

They warned that without timely intervention, Bangladesh could face a growing public health crisis—not from food scarcity, but from chemical contamination in everyday diets.

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