Title: An investigation of arsenic sources, speciation and mobilization processes in selected Irish aquifers
Researchers: Alex Russell, Prof. Frank McDermott
The World Health Organisation (WHO) estimates >200 million people may be exposed to chronic arsenic (As) poisoning globally. Dissolved inorganic arsenic species, the most common form of As in natural waters, are known carcinogens with epidemiological associations to ailments & cancers of the skin, kidneys, lungs and urinary tract amongst others . For this reason, the WHO has set out a global recommended limit of 10 μg/L for As in drinking waters, in Ireland the threshold value for arsenic is lower than this at 7.5 μg/L.
In Ireland, an estimated 26% of drinking water supplies are derived from groundwater sources . Geological environments similar to those in which high levels of dissolved arsenic occur elsewhere (e.g. sulphide bearing volcano-sedimentary sequences, unconsolidated glacial, fluvioglacial and alluvial deposits) are common in Ireland, yet reliable ppb-level As data for Irish groundwaters are sparse. Regulated public water supplies are known to contain arsenic, with the latest Environmental Protection Agency (EPA) drinking water reports indicating six exceedances of the 10 μg/L limit in the 2016 reporting period, and two during the 2017 reporting period. However, it is the estimated 170, 000 private wells which are of most concern in Ireland, as they currently remain unregulated. This is potentially leaving a significant population at threat from lesser known geogenic contaminants such as As.
This PhD project seeks to investigate the occurrence, speciation and geochemical processes responsible for the mobilisation of geogenic As in selected Irish groundwaters, focusing on private wells. Data generated in this PhD project will offer new scientific insights into the ‘arsenic problem’ that are applicable to public health both locally and globally. Original Project Objectives include: (1) Analysis of wells within the Dalradian rocks of Mayo & Donegal (NW Ireland). (2) Analysis of wells in unconsolidated alluvial, glacial and fluvio-glacial sediments in Kildare & Meath (KM). (3) Laboratory-scale leaching experiments on a selected range of lithologies from the aforementioned areas. (4) Qualitative assessment on the possible impacts of a changing climate on As mobilisation processes.