Project title: Understanding the fate of potentially toxic elements in the hyporheic zone
Researcher: Niamh O'Sullivan
Hyporheic zone of streams are considered to be reactive pathways for in-situ groundwater pollutant transformation. Arsenic presence in water has been linked to a number of geochemical conditions including the source of As, flow paths, redox states and microbial activity. The aim of the project is to develop a monitoring network in a first order stream where EPA testing has indicated a natural elevation of PTEs (AS, Al, U, Zn) in the groundwater, in an area dominated by agriculture activity, specifically livestock grazing. Groundwater modelling (PHREEQC) and 3D UV-via fluorescence spectroscopy (FEEM-PARAFAC) will be used to attempt to identify the environmental risks posed by heavy DOM introduction on PTE transfer from bedrock minerals to stream networks through the Hyporheic zone. The project objectives include:
- Identifying key hydrogeochemical processes and water rock interactions which control groundwater PTE mobility in siliceous bedrock.
- To understand the coupling between the carbon-redox system and PTE mobility in the hyporheic zone and to evaluate the geogenic PTE discharge potential to a first-order stream draining a high-risk aquifer.