Geochemistry Supports Food Sovereignty Through Sustainable Soil Remediation

Event Format: Hybrid (Zoom Access)

Speaker: Sarick Matzen, University of Minnesota — Twin Cities

Abstract:

I seek to understand how the chemical form of trace elements explains landscape-scale elemental cycles. I focus on contaminant cycling in urban agricultural soils, working in collaboration with community groups with the goal of advancing food sovereignty and environmental justice. Overall, I seek to support community groups in rehabilitating moderately contaminated soils into sites of local climate change resilience. To this end, I combine multiscale work at field to nano scales with advanced geochemical tools including synchrotron-based spectroscopy, revealing key aspects of biogeochemical cycles that determine bioavailability of contaminants like arsenic and lead.

I will first discuss remediation of arsenic-contaminated urban agricultural soils using plant-based removal, or phytoextraction, of arsenic with the arsenic hyperaccumulating fern Pteris vittata. Phytoextraction, the use of plants to remove contaminants from soil while leaving soil in place, is particularly attractive as a potentially low-cost, accessible, and sustainable remediation method in line with community values. I use a mass balance approach to show that up to 10% of arsenic leaches from soil during phytoextraction, with arsenic likely released from soil as a byproduct of plant nutrient scavenging. This previously overlooked impact of phytoextraction could contaminate groundwater. I then describe broad applications of my work characterizing trace metal transport via environmental nanoparticles, including work in oceanography and astrobiology.