Drugs in the environment and interactions with plants

Upon use of pharmaceuticals by humans, these compounds are often not fully metabolized in the organism but may be excreted in an intact form and released into municipal sewage systems. Even sewage treatment plants do not necessarily eliminate these pharmaceuticals so that they are continuously introduced at low levels into the environment. The effects on ecosystems are in many cases not fully known. Irrigation of agricultural crops may lead to exposure of plants to pharmaceuticals. Furthermore, sewage slugde sometimes used as agricultural fertilizer may lead to a contamination of plants by pharmaceuticals. In addition, veterinary drugs excreted by animals may lead to a direct introduction of these compounds into the environment. Finally, constructed wetlands for removing contaminants may be directly affected by residues of pharmaceutical drugs. It is mostly unclear if pharmaceuticals can be accumulated and if there is a significant extent of transformation that could lead to metabolites with toxicologically relevant properties. The focus of this project is the investigation of interactions of non-steroidal anti-inflammatory drugs with plants in the environment. This group of pharmaceutically active compounds is one of the most widely used classes of drugs and they are commonly detectable in the aquatic environment in the vicinity of effluents from sewage treatmen plants. Various plants with a focus on pea and maize will be used as models to investigate the uptake, accumulation and metabolization of the drugs and the effects on biomass, biochemical changes, and plant physiological parameters. For these studies, advanced analytical methods have to be developed and optimized in order to be able to identify and quantify traces of the parent drugs and their possible metabolites. The project will lead to detailed knowledge about the effects of pharmaceutical drugs in the environment with respect to uptake by plants, metabolic processes, induction of stress factors in plants, and impact on agricultural plant production. The development of modern analytical techniques will provide improved tools for monitoring residues of pharmaceuticals in the environment. This will have a significant potential for analyzing various classes of pharmaceutical drugs beyond those included in the present project.

Pharmaceuticals in the environment and their interactions with plants Due to medical progress, the use of pharmaceuticals is constantly growing in our society. Besides the positive effects, namely the possibility to treat more and more diseases successfully, there is also a negative side effect. Upon use by humans (or animals), drugs are often not fully metabolized in the organism and may be excreted in an intact form and released into municipal sewage systems. Growing population combined with climate change poses a dramatic threat to society, as the need for more food and feed is thwarted by water scarcity complicating the farming of the urgently needed crops. One way to overcome these obstacles (already practiced in many arid regions) is the use of reclaimed waters (i.e. water from sewage treatment plants) for irrigation in agriculture. Unfortunately, this practice involves the risk of plants being exposed to contaminants still present in these reclaimed waters. In the present project we investigated the interaction of plants (including crops employed in the production of food and feed) with a range of widely used pharmaceuticals. Thereby we developed experimental conditions allowing the growing of a range of plants while subjected to pharmaceuticals commonly detected in the effluents of municipal wastewater treatment plants. By analyzing extracts from plants treated with these substances, we could show that the drugs are not only taken up by the plant via the roots, but also translocated to other parts such as stem, leaves or fruit. Some of the substances were even transformed into a variety of metabolites (many of them previously unknown within this context) in the plant. For this purpose new analytical approaches had to be developed not only for the proper extraction of these substances from the plant matrix but also for the subsequent analysis of the extracts. Thereby using sophisticated analytical instrumentation was used, allowing the identification of the metabolites and proposing tentative structures for these molecules even at trace levels of concentration. This resulted in the detection of a range of new metabolites formed within the plants upon uptake of the drugs from water. Through cooperation between the Institute of Analytical Chemistry at the Johannes Kepler University in Linz and the Section of Experimental Plant Biology of the Masaryk University Brno we were able to combine scientific findings from analytical chemistry (identification of new drug-related metabolites formed within plants) with those from biological tests namely the effect of these substances on plant growth and plant anatomy.