Elucidation and prediction of fate, speciation, and transformation processes for polar contaminants of emerging concern in wastewater-impacted environments

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Chemical pollution is a serious and increasing problem in our society. To understand the risks of chemicals on human and ecosystem health, we must characterize their environmental behavior and fate. Chemicals such as drugs are designed to have profound biological effects, and are therefore of increasing environmental concern. Once taken up, many drugs are well known to be metabolized and excreted by humans and other organisms. While efforts are currently under way to identify these degradation products in the environment, very little is known about environmental levels of inputs of these products, their behavior and fate, or their effects and impact. Existing evidence points to fears that these products may rival the original drugs in concentrations and can turn back into the original compound. Being able to predict the fate and transport of drugs and their degradates is vital given increasing release of wastewaters impacting ever more receiving waters, and increasing reuse of reclaimed wastewater and biosolids for irrigation and fertilizer.******We will address these severe knowledge gaps. First, we have developed new and better ways to sample, separate, and quantify drug degradates from their parent compounds in waters, and remove interfering compounds. We will use these methods, modified as needed, to understand how much of both parent and degradate are present in wastewater treatment plants and in receiving waters, and what physical, chemical, biological, and ecological processes control these levels. This will be done through lab-based experiments in bioreactors for controllable experiments to predict real-world levels in wastewater treatment plants, and in waters impacted by inputs. ******Second, we will evaluate how plants can deal with drugs and their degradates. Human exposure can occur when crops irrigated or fertilized with wastewaters and biosolids contaminated with drugs can take up these chemicals. Also, plants can be used to remediate contaminated areas, such as with constructed wetlands; while they are known to degrade many contaminants, drugs and their degradates are poorly studied to date. We will measure uptake of drugs and degradates through the root system, to build predictive models relating uptake to physical-chemical properties of drugs, physiological properties of plants, and environmental conditions such as pH. We will evaluate how plants may move drugs from roots to shoots, leaves, fruits and seeds, again for predictive purposes We will also study transformation dynamics of drugs by plants both whole, and using enzyme extracts and cell cultures for more controllable experiments, to evaluate and predict potentials of plants for degrading these chemicals.******This work will ultimately play a significant role in remediating, maintaining, improving, and protecting our precious water and food resources by providing insights into how drugs and degradates behave in these systems.