iCRAG PhD GW3.2PhD1
An investigation of uranium occurrence, sources and mobilization processes in
selected Irish groundwaters
This PhD project will investigate the occurrence, sources and processes responsible for
geogenic uranium mobilisation in selected Irish groundwaters. In Ireland, groundwaters from
fractured Caledonian and Tertiary granites and from Carboniferous limestone-shale
successions can contain levels of dissolved uranium that exceed World Health Organisation
(WHO) limits. Reliable uranium data for Irish groundwater at the ppb level remain sparse
however.
This project seeks to better understand and quantify the fundamental
hydrogeological and hydrochemical processes that control uranium mobilisation and
transport in these two distinct aquifer types. In a recently published reconnaissance survey
of 200 public groundwater samples from across the Republic of Ireland, dissolved uranium
concentrations exceeded the 2 g/L WHO limit in 10% of the sampled wells. However,
almost no reliable data exist for much larger number of private wells (>100,000) that provide
the main source of drinking water in several regions. In regions where elevated
concentrations have been demonstrated, the underlying geochemical processes responsible
for uranium mobilisation and transport are currently not well characterised, and this will be a
major focus of the PhD. Three geographical areas linked to geological settings linked to
Caledonian granites and Namurian shales have been selected for an initial focus in the PhD,
based on pilot studies. Analysis of mineralogical sources/sinks from selected field sites and
from laboratory based leaching experiments will use X-Ray Diffraction (XRD), Scanning
Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM-EDS), and
Transmission Electron Microscopy (TEM). The student will also undertake U-series
measurements (e.g. 234U/238U ratios) at the National Centre for Isotope Geochemistry (NCIG)
to constrain the nature of the sources (primary versus secondary remobilised) and the
timescales of mobilisation processes.
Applications are invited from candidates who have a BSc in a relevant geoscience area, with
an MSc in hydrology or hydrogeology. The successful candidate will join a large applied
geoscience research centre, iCRAG, in the UCD School of Geological Sciences at University
College Dublin: iCRAG is national research centre with a presence in all of the Irish research
institutions involved in Geosciences. The position is fully funded for four years with a
scholarship of €18K/year. To apply please submit a full CV and contact details for 3
academic referees, together with a letter of motivation, to Prof. Frank McDermott
(frank.mcdermott@ucd.ie), from whom further particulars may also be requested: the
application deadline is 21st August 2015. iCRAG is funded under the SFI Research
Centres Programme and is co-funded under the European Regional Development Fund.