Perfluoroalkyl acids (PFAAs) are persistent environmental contaminants that sorb to air–water and solid interfaces throughout the vadose zone. These sorption processes lead to decadal leaching of PFAS from the source zones to groundwater systems. While these processes are increasingly well understood, critical gaps exist in describing the vertically variable adsorption in the presence of vadose zone heterogeneity and methods for efficiently upscaling the laboratory observations to predict field-scale PFAA transport and retardation. In this work, we build upon fundamental theories and scalable relationships to define a semi-analytical framework for synthesizing and upscaling PFAA adsorption in heterogeneous vadose zone systems. Solid-phase and air–water interfacial adsorption are quantified mechanistically for several PFAAs and then applied to a contaminated site in Northern Wisconsin. The results highlight the dominance of air–water and organic carbon solid-phase adsorption processes in the vadose zone. Strong sorption heterogeneitydriven by depth-dependent adsorption mechanismsproduces complex spatially variable retardation profiles. We develop vadose zone retardation potentials to quantify this field-scale heterogeneity and propose vertical integration methods to upscale spatially resolved information for transport modeling. This work highlights the importance of accounting for multiscale and multiprocess heterogeneity for accurately describing and predicting the long-term fate and transport of PFAAs in the subsurface.

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Origin and Evolution of the Sul de-Rich, Ma c Igneous Intrusion at Eagle Mine, Upper Peninsula, MI The Eagle Mine of the Upper Peninsula, Michigan is host to a productive copper-nickel, sul de-rich ore deposit that is hosted within the Yellow Dog Intrusion, a ma c intrusive igneous rock. The origin of the ore and its relationship to its host intrusion are not known. To better understand the processes responsible for the formation of the deposit, we collected a series of rocks from the mine that represent distinct crystallization phases of the intrusion. Here, we apply a new model for di erentiation within ma c magma chambers: the Sequential Extraction model. The model invokes the process of liquid immiscibility to generate complementary Si-rich and Fe-rich melts that, due to signi cant di erences in density, rapidly segregate upon formation. We use whole-rock and trace-element geochemistry to follow chemical evolution within the magma chamber, and we apply petrographic techniques to observe characteristic textural features associated with segregated liquids within a crystallizing magma body. We show that the Cu, Ni deposits are co-magmatic, and that their origin is tied to the segregated Fe-rich liquid. Abstract