Vegetables from urban gardens may contain heavy metals and pesticides.

Crops grown in urban allotment gardens are associated with healthy, local food. Recent research from the Institute of Environmental Protection - National Research Institute shows that carrots, lettuce, and strawberries grown in such areas may contain heavy metals, pesticide residues, and even traces of antibiotics.

In 2022-2023, scientists from the Institute of Environmental Protection - National Research Institute (IOŚ-PIB) examined soil and plant samples from 16 Warsaw allotment gardens. Their analysis showed that one kilogram of such soil contained an average of 0.8 mg of cadmium and 12 mg of lead. These contaminants penetrate plants, including edible plants.

In root vegetables such as carrots, beets, and parsley, researchers recorded an average of 0.9 mg/kg of cadmium and 14.5 mg/kg of lead, while in leafy vegetables such as lettuce and spinach, they were 1.4 mg/kg and 11 mg/kg, respectively. In tomatoes and strawberries, the concentrations of heavy metals were lower but still detectable.

In addition to metals, the scientists also detected pesticide residues in the plant samples, including chlorpyrifos, malathion, and diazinon. Their concentrations reached several hundredths of a milligram per kilogram. While this falls within the applicable standards, IOŚ-PIB experts noted that long-term consumption of such products can lead to the gradual accumulation of chemicals in the body.

- Regular consumption of vegetables and fruits containing residues of heavy metals and pesticides may lead to their accumulation in the body, which increases the risk of various diseases, including neurological problems, kidney damage, hormonal disorders, weakening of the immune system, and in the long term even cancer - warned Prof. Barbara Gworek, head of the Department of Environmental Chemistry and Risk Assessment at IOŚ-PIB, initiator and co-author of the study, quoted in a press release sent to PAP.

Data from the National Institute of Public Health (PZH–PIB) indicate that these substances are not the only contaminants present in Polish fruits and vegetables. In the past, linuron, diazinon, and trifluralin (in carrots) and dimethoate (in cucumbers) have been detected in them. Fungicides such as captan and thiophanate-methyl have also been detected in tomatoes.

Although most commercially available food does not exceed acceptable standards, environmental factors, such as proximity to streets with heavy traffic or the proximity of former industrial areas, also influence pollution levels in urban gardens.

The research team also noted the presence of antibiotics in natural fertilizers used in amateur cultivation. Samples of cattle manure, often used in organic farming, detected tetracycline, oxytetracycline, and chlortetracycline, among other substances. Experts point out that although these amounts were small, the regular use of such fertilizers can, over time, lead to the accumulation of these substances in the soil and promote the development of antibiotic-resistant bacteria.

To reduce health risks, experts recommend thoroughly washing, peeling, or blanching vegetables before consumption, which can reduce the content of harmful substances by up to half. It's also important to use fertilizers from reputable sources and avoid using pesticides on home-grown crops.

- This is the only way we can ensure that vegetables and fruit from urban gardens will be a healthy and safe source of food - noted Professor Gworek.

The authors of the analysis pointed out that although this particular study was conducted in Warsaw, similar pollution is very likely to occur in other Polish cities.

Katarzyna Czechowicz (PAP)

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