Graduate Exit Seminar - Ying-Ren Lai

Plan to join Ying-Ren Lai's graduate exit seminar on April 8, 2026, at 1:00 pm at Kottman Hall 333C or via Zoom. Ying-Ren will present, "Soil–Amendment Controls on Phosphorus Retention, PFAS Mobility, and Arsenic Remediation Under Varying Redox Conditions"

Abstract: Phosphorus (P) loss from agricultural systems and the spread of persistent contaminants from soil amendments represent two challenges for sustainable land management. Excess dissolved runoff phosphorus (DRP) released from agricultural lands accelerates eutrophication and harmful algal blooms, yet many conventional best management practices are designed to control sediment and particulate P rather than the dissolved fraction. In parallel, beneficial reuse of municipal residuals such as biosolids can improve soil fertility and divert waste from landfills, but biosolids can also introduce per- and polyfluoroalkyl substances (PFAS) that may leach to groundwater and move through connected surface waters. A third, related concern arises in contaminated soils where arsenic (As) mobility and toxicity are strongly governed by redox fluctuations, especially under flooding or changes in water table position. Together, these issues motivate a common need for management strategies and decision tools that are mechanistically grounded in soil chemistry, that explicitly evaluate risk tradeoffs, and that remain effective under realistic field-relevant conditions. This dissertation integrates three projects to evaluate (i) how reactive byproducts can be used to reduce soluble P loss from organic nutrient sources, (ii) how soil physicochemical properties control PFAS leaching from biosolids-amended soils under percolation, and (iii) how redox dynamics govern the performance and stability of iron (Fe)- and aluminum (Al)-based sulfate amendments for As immobilization.

Advisor: Dr. Nicholas Basta