Crops irrigated with wastewater store drugs in their leaves

Science News from research organizations Crops irrigated with wastewater store drugs in their leaves Scientists discovered that crops irrigated with wastewater mostly stash trace pharmaceuticals in their leaves rather than the parts we eat. Date: March 15, 2026 Source: Johns Hopkins University Summary: Scientists studying crops irrigated with treated wastewater discovered that trace pharmaceuticals often collect in plant leaves. Tomatoes, carrots, and lettuce absorbed medications such as antidepressants and seizure drugs during the experiment. However, the edible portions of tomatoes and carrots contained much lower levels than the leaves. The findings help researchers understand how crops process contaminants as wastewater reuse becomes more common. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Tomato plants exposed to psychoactive pharmaceuticals for 45 days after flowering stored higher concentrations of the drugs and byproducts in their leaves compared to their fruits. Credit: Daniella Sanchez, Johns Hopkins University In regions where freshwater supplies are limited, farmers sometimes rely on treated wastewater to water their crops. While this practice helps conserve scarce water resources, it has raised concerns among regulators and consumers. Wastewater can contain trace amounts of various substances, including psychoactive medications commonly used to treat mental health conditions. New research from Johns Hopkins University suggests that certain crops -- tomatoes, carrots, and lettuce -- tend to store these chemicals mainly in their leaves. This finding may be reassuring for people who eat tomatoes and carrots, since the parts we typically consume are the fruit and the roots rather than the leaves. The study, published in Environmental Science and Technology , is part of a broader effort to understand the safety of irrigating crops with municipal wastewater. In most cases, this water has already been processed through treatment facilities before being reused. "Farming practices place a high demand on freshwater resources. With limited rainfall and droughts threatening global water supplies, we're looking at a future with shortages that may only be met by repurposing treated wastewater," said Daniella Sanchez, a doctoral student at Johns Hopkins University and lead author on the study. "To continue to use wastewater safely, we need a more sophisticated understanding of where and how crop species metabolize, or break down, agents in the water." Studying How Crops Absorb Psychiatric Medications Sanchez examined four psychoactive pharmaceuticals frequently detected in treated wastewater: carbamazepine, lamotrigine, amitriptyline, and fluoxetine. These medications are prescribed to treat conditions such as depression, bipolar disorder, and seizures. To study how plants interact with these drugs, the researchers grew tomatoes, carrots, and lettuce in a temperature-controlled chamber. The plants were supplied with a nutrient solut