Location: Water Management and Conservation Research
Project Number: 2020-13660-009-035-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2026
End Date: Dec 31, 2027
Objective:
Evaluation of PFAS adsorption, degradation, and movement in agricultural soils after surface application of PFAS containing livestock manure, biosolids, and reclaimed wastewater.
Approach:
Per- and polyfluoroalkyl substances (PFAS) are becoming one of the major emerging class of contaminants and posing risks to crop production and human health. PFAS compounds are derivatives of agricultural pesticides and industrial and consumer products. They are slow to degrade and possess unique transport properties that are not well understood. In this project, researchers will apply the HYDRUS model to simulate adsorption, degradation, and movement of PFAS chemicals under three agricultural scenarios. First, the model will be parameterized to evaluate PFAS transport when composted livestock manure is applied at the soil surface. Application of livestock manure as a soil amendment can increase soil organic matter content, supply essential plant nutrient, and reduce soil pH. This is especially beneficial to Arizona agriculture where the soils are low in organic content and high in pH, limiting crop growth and nutrient update. The movement of PFAS chemicals from the surface-applied manure to subsurface soils will be simulated with the HYDRUS model. Second, the model will be used to determine PFAS transport from municipal biosolids applied to agricultural soils. Similar to livestock manures, biosolids are often applied to crop land to supply plant nutrients, improve soil structure, and increase soil water holding capacity. However, biosolids often contain significant amounts of PFAS compounds that are different in chemical and transport properties than those found in livestock manures. Third, the model will be reconfigured to simulate the retention, degradation, and infiltration of PFAS chemicals found in reclaimed wastewater when used for irrigation.