The purpose of the project is to establish a risk assessment framework that can estimate human health risks based on measurements of antibiotic resistant bacteria (ARB) and antibiotic resistant…

The purpose of the project is to establish a risk assessment framework that can estimate human health risks based on measurements of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (args) in source waters under the influence of municipal wastewater and biosolids. The research will generate field data collected from surface water which will be used to calibrate and validate mechanistic fate-and-transport models for ARB and args in runoff and rivers. Once developed, these models will inform development of an exposure assessment model for ARB and a semi-quantitative risk characterization model for args to improve stakeholders' abilities to understand risks and develop/prioritize mitigation strategies.activities:the project will start by collecting samples from a variety of wastewater discharging facilities located in new jersey, nebraska, california, and hawaii. Including point and non-point AMR sources, water reuse scenarios (DE-facto, non-potable, potable), and environmental settings (treatment plant flow, water age, average precipitation). Water samples will then be collected from receiving water bodies at multiple distances downstream during both dry and wet weather conditions from AMR discharges. A separate effort will focus on sampling AMR levels in land applied biosolids using field plots in NE to estimate and model concentrations of ARB and args in runoff. Using the above information, fate and transport models will be calibrated to model ARB and args in each of the selected rivers to predict concentrations downstream, explore relative significance of various point and non-point sources and provide information for risk assessment modeling. Last, a risk assessment framework will be developed to evaluate the relative importance of exposure pathways and risk from wastewater originated ARB and ARG levels in rivers. Subrecipient:university of aawaii at manoa (YAN) - objective 1: generate data from field and laboratory studies. ($251,124 + cost share $63,176 = $314,300) university of california riverside (meng) - objective 1: generate data from field and laboratory studies ($278,327 + cost share $69,626= $347,953) rutgers university (fahrenfield) - objective 1: generate data from field and laboratory studies. ($421,553 + cost share $105,391= $526,944) iowa state university (ikuma and rehmann) - objective 4: fate and transport modeling for rivers. ($273,866 + cost share $68,629 = $342,495) outcomes:key deliverables include new information on ARB and ARG levels and source attribution of AMR from wastewater and non-wastewater sources. A calibrated and validated mechanistic model will be developed to estimate the significance of AMR loads in surface water to increase the ability of water resource managers to evaluate ethe significance of AMR from land-applied biosolids and wastewater. A risk/exposure assessment model will then be developed to evaluate multiple exposure pathways for ARB and exposure routes for args. Key outcomes from the project include improved ability for water resource managers to assess the significance of AMR from wastewater and biosolids along with the ability for stakeholders to quantify the exposure and risk of wastewater originated ARB and args in rivers. Beneficiaries include the public, state and local regulators, wastewater utilities and water quality program managers.