As a society, we rely on drugs and pharmaceuticals to improve and extend our lives, but these pharmaceuticals make their way from our bodies into wastewater, even after it has been treated. Treated wastewater is used to irrigate crops, but we don’t know what effect residual pharmaceuticals have on crops and plants.
As the global population grows, freshwater needs to be reserved for human consumption, so reclaimed wastewater can be used to irrigate crops. The problem is that only 1% of the irrigation water has been treated. Some countries like Israel use 85% of treated wastewater for crop irrigation, but current water purification technology can’t get rid of all the pharmaceuticals that end up in wastewater. That means that there are now increasing amounts of pharmaceuticals entering the agricultural system.
A group of researchers from the Hebrew University of Jerusalem set out to study whether pharmaceuticals in the water caused a stress response in plants. They did so by bathing the roots of tomato seedlings in a mix of various pharmaceutical compounds (CBZ, LTG, VAL, PHY, and DZP) and they bathed a control group in water. CBZ (Carbamazepine) is one of the most abundant pharmaceuticals found in wastewater. The researchers used a higher concentration of pollutants in their tests than is normally found in wastewater so that they could enhance the stress response of the plants to better identify what was happening to the plants.
After five days, the tomatoes that were treated with the highest concentration of pollutants had all collapsed. Plants bathed in lower concentrations performed as well as the plants bathing in water. The researchers concluded that the pharmaceuticals present in wastewater do have an effect on plants and produced a typical stress response in the tomato plants studied.
The results of the study were published in Scientific Reports.