The assimilative capacity of a groundwater system largely depends on the aquifer matrix. Volcanic profiles may have the potential to assimilate significant quantities of nitrate (NO₃⁻) due to the presence of relict organic matter in the form of palaeosols (buried soils) and vegetation covered by deposits during the eruption. This organic material could provide the necessary electrons required to fuel heterotrophic denitrification, and reduce environmentally damaging NO₃⁻ to inert dinitrogen (N₂) gas
