Sewage contains antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), some of which may persist, be amplified, or attenuated through wastewater treatment. To support comprehensive strategies to mitigate the spread of antimicrobial resistance (AMR), there is a need to better quantify outputs of ARB/ARGs from wastewater treatment plants (WWTPs) to the environment and to characterize potential impacts. The overall objective of this program project is to generate a comprehensive study of ARB/ARGs in WWTP effluent and biosolids, wherein we will quantify and model their fate in aquatic and soil environments. Our goal is to characterize exposure potentials and create a comprehensive risk assessment modeling framework tailored to the unique aspects of AMR and enabling the evaluation of potential mitigation options. We will pursue five objectives: OBJ. 1. Determine ARB/ARG mass loading ranges in WWTP effluents and biosolids as a function of WWTP characteristics; OBJ. 2. Estimate the degree to which WWTP effluent and biosolid-borne ARB/ARGs attenuate or amplify in the environment and identify controlling factors; OBJ. 3. Evaluate evidence of WWTPs as a source of AMR infections in humans, relative to other sources, across a range of US communities that reflect a spectrum of wastewater management scenarios; OBJ. 4. Develop a human health risk assessment for WWTP effluent and biosolid sources of ARB/ARGs based on the knowledge gaps addressed through OBJ 1-3; OBJ. 5. Engage with stakeholders and translate the research into actionable solutions.