CAREER: Determining how flow of polluted water impacts antibiotic resistance in soils

Antibiotics provide a textbook example of biologically active chemicals that can impact human, animal, and ecosystem health. In soils, many bacterial strains carry genes that encode for antibiotic resistance (AR). The use of treated wastewater for irrigation has emerged as an important source of antibiotics in soils.

In agriculture fields irrigated with treated wastewater, previous studies have found that antibiotics are frequently detected in soils. In addition, some studies have reported that irrigation intensity and the occurrence of AR markers in irrigation water are correlated to the abundance of those markers in soils. However, a fundamental understanding of the fate, transport, and reactivity of antibiotics in agricultural soils during irrigation with treated/polluted wastewater has remained elusive.

The overarching goal of this CAREER project is to advance the fundamental understanding of the reactive transport processes that occur during the infiltration of antibiotic-polluted water and their impact on the levels of AR bacteria in agricultural soils. To advance this goal, the Principal Investigator proposes to test the hypothesis that changes in the abundance and persistence of AR bacteria in agricultural soils are directly linked to the physicochemical interactions between soils and antibiotics during the infiltration of treated/polluted irrigation wastewater.

The successful completion of this project will benefit society through the generation of new fundamental knowledge on how soils function as natural filters that accumulate and/or degrade antibiotic pollutants and control their availability to soil micro-organisms. Additional benefits to society will be achieved through student education and training including the mentoring of two graduate students and one undergraduate student at Texas A&M University.

Antibiotic pollutants are a group of chemicals that infiltrate through soils during irrigation when treated wastewater is used as alternative to address water scarcity in agriculture. Despite the importance of soils in assimilating antibiotic pollution, little is known about how the flow of antibiotic-polluted water impacts the spread and persistence of antibiotic resistance (AR) in soils during irrigation.

This CAREER project will address these critical knowledge gaps through the integration of field investigations, bench scale lab experiments, and process-based modeling. The specific objectives of the research are to (1) identify the factors that control the persistence of antibiotics and the amplification of AR markers in soils irrigated with treated wastewater, (2) identify and quantify the soil-antibiotic interactions that induce persistence and horizontal transfer of AR genes among soil bacteria, and (3) elucidate key reactive processes controlling the amplification of AR in soils that receive a mix of antibiotics and AR bacteria in polluted water.

The successful completion of this project has the potential for transformative impact through the generation of new data and fundamental knowledge about the AR attenuation capacity of soil ecosystems under the continuous infiltration of antibiotic polluted wastewater. To implement the educational and mentoring goals of this CAREER project, the Principal Investigator proposes (PI) to leverage existing programs and resources at Texas A&M University to (i) engage students in the design, implementation, and deployment of a human-like dynamic conversation interface (educational chatbot), and (ii) use the educational chatbot to promote interactive communication between virtual STEM scholars and K-12 student audiences.

The PI plans to build upon these educational activities to design and implement new pedagogical frameworks that foster equal participation and a sense of belonging among all students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.