The growth of edible crops can be affected by a range of non-steroidal anti-inflammatory drugs, even at the very low concentrations found in the environment, according to a recent study.
Researchers from the University of Exeter found that the potential for some chemicals to influence plants is becoming increasingly relevant, particularly as waste management systems are unable to remove many compounds from sewage. Drugs for human use make their way into soil through a number of routes, including the use of sewage sludge as fertilizer and waste water for irrigation.
"The huge amounts of pharmaceuticals we use ultimately end up in the environment, yet we know very little about their effects on flora and fauna," Dr Clare Redshaw, one of the scientists leading the project at the Medical School's European Centre for Environment & Human Health, said in a statement. "As populations age and generic medicines become readily available, pharmaceutical use will rise dramatically and it's essential we take steps towards limiting environmental contamination."
The research focused its analysis on lettuce and radish plants and tested the effects of several commonly prescribed drugs, including diclofenac and ibuprofen. These drugs are among the most common and widely used group of pharmaceuticals, with more than 30 million prescribed across the world every day.
For the study, researchers looked for a number of changes in edible plants, assessing factors such as water content, root and shoot length, overall size and how effectively the plants photosynthesized.
Each drug was shown to affect the plants in very specific ways, with marked differences between drugs that are closely related. For example, drugs from the fenamic acid class affected the growth of radish roots, whilst ibuprofen had a significant influence on the early root development of lettuce plants.
There have been growing concerns about the presence of pharmaceuticals in the environment, particularly as evidence emerges of the effects they can have on the development of animals and antibiotic resistance in bacteria. Yet their ability to affect plant growth is poorly understood.
"We haven't considered the impact on human health in this study, but we need to improve our understanding quickly so that appropriate testing and controls can be put in place," Redshaw said.
This study marks an important step in an emerging research field attempting to assess how very low concentrations of drugs can affect the growth of crucial crop plants.
The findings are detailed in the Journal of Ecotoxicology and Environmental Safety.
