Using Targeted and Non-Targeted Mass Spectrometry Based Analyses to Identify the Most Efficient Wastewater Treatment Processes for Removal of Antibiotics and Other Emerging Contaminants

Wastewater is a unique matrix for identifying and assessing threats to environmental and human health. Wastewater contains a mixture of thousands of chemicals released by human activities related to household care, industries, pharmaceuticals, and personal care products. The complexity of this mixture is exacerbated by compounds derived from biological and physico-chemical transformations, including human metabolism, and treatment processes such as ozonation, chlorination, UV, filtration, and biological degradation. Among the compounds found in wastewater, antibiotics are of particular interest because of their potential to interact with digestive bacteria and create antibiotic-resistant “superbugs” during the water treatment
process. In this study, we aimed to identify water treatment processes that have the highest potential to remove antibiotics and other contaminants of interest from wastewater before they are released into the environment. Influent, intermediate effluent, final effluent, sludge, biosolids, and digestates were collected from 40 wastewater treatment plants (WWTPs) across the country using a community-engaged approach. Samples were extracted using solid phase extraction and analyzed via liquid-chromatography coupled to high-resolution mass spectrometry in the data-dependent acquisition mode.

We used a combination of targeted (for 13 antibiotics to be quantified) and non-targeted approaches, in addition to suspect screening with open-access spectral libraries. Suspect screening will assist us in the identification of additional potential contaminants for further confirmation. Our ultimate goal is the assessment of treatment practices that enhance the degradation or transformation of antibiotics and other environmental contaminants, and to communicate these results to other WWTPs for their implementation. This will lead to safer wastewater discharge, which benefits human and
environmental health.