Water-soluble contaminants present a wicked challenge for green stormwater infrastructure (GSI), which have been historically designed for particles and particle-associated contaminants. Soluble nutrients (e.g., nitrate, dissolved phosphorus) and hydrophilic trace organic contaminants (e.g., pesticides, vehicular compounds, building biocides) cannot be conventionally filtered and poorly sorb to conventional bioretention media, thereby presenting a risk to receiving waters if these contaminants pass through. There is thus a critical need to understand the fate of soluble contaminants in green stormwater infrastructure and improve sustained removal processes through innovations in GSI geomedia.