CAREER: Advancing Managed Aquifer Recharge on Agricultural Land by Understanding the Redistribution of Naturally Occurring Metals

Reliable water supplies in agricultural regions are critical for long-term water and food security. A strategy called "managed aquifer recharge" stores extra surface water in aquifers. During wet periods, farmlands can be flooded to replenish groundwater. This water can later be used during dry periods or drought. This approach increases water supplies, but it can also affect water quality. Soils naturally contain toxic metals such as arsenic and uranium. When soil conditions change during flooding, these metals can move into groundwater. This CAREER project will study how managed aquifer recharge affects the movement of these metals in soils and water. The project will combine field sampling, laboratory experiments, spectroscopy, and transport modeling to identify fundamental processes the control the redistribution of toxic metals. Project outcomes will aid the development of water management strategies that increase water storage while protecting groundwater quality for crops and communities. This CAREER project will evaluate how flood managed aquifer recharge promotes fine-scale redox heterogeneity in agricultural soils that ultimately governs the redistribution and speciation of naturally occurring metal(loid)s in soil systems. The research will investigate how flooding scheme, soil type, and irrigation-water composition influence metal release to porewater, transport to groundwater, and bioavailability for plant uptake. Controlled laboratory experiments will be combined with reactive transport modeling to quantify the development and persistence of microscale redox heterogeneity by simulating managed aquifer recharge in agricultural soils. The work will address fundamental gaps in understanding how hydrologic perturbations induced by managed aquifer recharge alter redox structure and metal behavior in complex agricultural systems. Although this work will focus on the context of flood managed aquifer recharge, findings will be broadly applicable to agricultural soil systems experiencing cyclic flooding and intensification of the hydrologic cycle. Educational and outreach activities will be integrated with the research to translate findings into workforce development and professional training opportunities related to water management. 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. NSF Award ID: 2544063 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Sarah Fakhreddine | Institution: Carnegie Mellon University, PITTSBURGH, PA | Award Amount: $735,333 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2544063 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2544063.html