New research examines how strawberries, lettuce and carrots absorb microcystins, raising questions about food safety and environmental interactions.

Could the water used to grow our food be carrying invisible toxins into our crops? A new study published in February 2025 in the Journal of Agriculture and Food Research has found that microcystins - harmful substances produced by cyanobacteria - can be absorbed by strawberries, lettuce, and carrots when irrigated with contaminated water. The findings highlight the need to better understand how these toxins accumulate in crops and their potential implications for food safety.

Cyanobacterial blooms, which thrive in nutrient-rich waters, are becoming more frequent due to climate change and agricultural runoff. These blooms are well known for their impact on drinking water and aquatic ecosystems, but less is understood about their effects on crops irrigated with contaminated water. Previous studies on microcystin accumulation in plants have often relied on controlled laboratory conditions that do not fully reflect real-world agricultural practices.

To address this gap, scientists from Belgium, including Imptox researchers  Andreja Rajkovic from Ghent University and Mirjana Andjelkovic from Sciensano, conducted a greenhouse study to evaluate how lettuce, carrots, and strawberries absorb microcystin-LR (MC-LR), a particularly potent form of the toxin. They tested two irrigation methods: spray irrigation (which mimics rain by sprinkling water over plants) and drip irrigation (which delivers water directly to the soil).

The results showed that strawberries absorbed MC-LR in their roots and leaves under both irrigation methods. However, MC-LR was only found in strawberry fruit when spray irrigation was used. Lettuce also accumulated the toxin, with MC-LR present in its outer and middle leaves. In contrast, only a limited number of carrot samples showed MC-LR accumulation, making the results inconclusive for this crop. Notably, in strawberries, MC-LR was found in the leaves even when only the roots were exposed through drip irrigation, suggesting that the toxin can move within the plant.

The study emphasizes that the accumulation of MC-LR in strawberries and lettuce warrants further investigation into the extent of possible health risks and their implications for public safety. Researchers stress the importance of understanding how irrigation methods influence toxin absorption and the potential for microcystins to move within plant structures.

Beyond the findings on crop contamination, scientists are now looking at a broader question: What happens when microcystins and micro- and nanoplastics (MNPs) interact? The EU-funded Imptox project is particularly interested in exploring how these two environmental pollutants behave together, whether MNPs could affect microcystin absorption, toxicity, or distribution in plants and the human body.

This study is a reminder that environmental pollution doesn’t exist in isolation. What enters our water doesn’t just stay there - it can travel through plants, food, and possibly even human bodies. As climate change fuels more frequent cyanobacterial blooms and microplastics continue to infiltrate ecosystems, understanding these interactions is crucial. Could pollutants amplify each other’s effects? Could they change how toxins move through the food chain? One thing is certain: there’s more to this story, and science is only beginning to unravel it.

Reference:

Wannes H.R. Van Hassel, Elise Tardy, Bart Cottyn, Mirjana Andjelkovic, An Decombel, Jeroen Van Wichelen, Julien Masquelier, Andreja Rajkovic, Irrigation-dependent accumulation of microcystin in different crops under mid-scale greenhouse conditions, Journal of Agriculture and Food Research, Volume 20, 2025, https://doi.org/10.1016/j.jafr.2025.101753