Evaluating fungal-based nature-based solutions for agricultural drainage treatment

Diffuse nutrient pollution from agricultural runoff remains a major pressure on freshwater systems, contributing to eutrophication and downstream ecosystem degradation. Nature-based solutions (NbS) that can be deployed close to source are increasingly sought as cost-effective and multifunctional alternatives to conventional treatment approaches. Mycoremediation, using fungi to transform or retain contaminants, has potential but remains largely untested for promoting nutrient concentration and load reductions in agricultural drainage waters. Through a tiered experimental framework, we evaluate fungal-based filter matrices designed to treat agricultural runoff, with a primary focus on nitrate (NO₃⁻) and phosphate (PO₄³⁻) removal. This presentation focuses on the design, comparative performance, and field evaluation of fungal-based NbS for agricultural drainage treatment.

Filters combine organic and inorganic substrates selected to promote fungal colonisation and sustained biogeochemical activity. Saprotrophic fungal strains originating from England and Scotland were isolated, genetically confirmed, and screened under laboratory conditions to assess nutrient uptake performance. Column experiments enabled the shortlisting of substrate–fungal combinations with the strongest nutrient removal potential. Selected combinations were then tested in channel-scale experiments simulating agricultural drainage conditions using water enriched with NO₃⁻ and PO₄³⁻. We quantify upstream and downstream nutrient concentrations, dissolved oxygen dynamics, and redox potential within the filter media to assess conditions conducive to denitrification and nutrient retention. In parallel, continuous water quality monitoring is being used to assess filter performance under real-world hydrological and chemical variability across multiple agricultural sites in England and Scotland.

Data collection is ongoing and results are not yet conclusive; however, the combined laboratory, mesocosm, and field datasets will provide a robust evaluation of mycoremediation filters as scalable NbS for mitigating diffuse agricultural nutrient pollution.