Abstract by Schuyler Robinson
Groundwater Particle Tracking in NE Oahu
The genus Mycobacterium is a cause of increasing death and disease in immuno-deficient individuals in the USA and across the world due to pulmonary infections from a subset of species termed NTM (non-tuberculous mycobacteria), and is particularly prevalent in Hawaii. A proposed route of human infection is aerosol inhalation from NTM biofilms within showerheads. Little is understood regarding the transport of NTM from the environment to indoor plumbing, although transport from surface water to water-supply aquifers is likely important. This study analyzes groundwater flow from stream losses as a method of NTM transport to water supplies. A MODFLOW groundwater model was developed for NE Oahu for the Waimea Stream drainage. Adaptations were made to an existing well water source protection model developed in 2004 to include stream flow losses. Backward particle tracking from 2 nearby wells to Waimea Stream suggest that water entering the well came from the up-gradient Waimea and Kamananui Streams. Results show hundreds of meters of lateral and tens of meters vertical transport in 1-3 months. As an oligotroph, NTM may survive during this transport time.