Comparative hydro-geochemistry: Distribution of metal ions in ground water, surface water, soils and plants in the South East of Ireland

Abstract

Until recently lithium has been an unpopular, often unthought of metal tucked away on the far left of the periodic table. You might recall a song or two of the same name, or that it is used to treat bipolar disorder, but that’s about it. Today lithium is more popular than ever because it is the main component of rechargeable lithium ion batteries. Lithium batteries represent the best battery technology that is commercially available to date. These batteries are powering our portable electronics and are set to power the vast electric vehicle landscape of the future. The global electric vehicle market is growing rapidly, and along with it the demand for lithium resources. In chapter one, the geological sources and industrial uses of lithium are discussed. This chapter focuses on the European Union’s need to develop its own lithium resources and the potential future security of supply issue. Geographically small lithium mineralisations are distributed all over the world. One of these small mineralisation’s is found in the South East of Ireland and is the main impetus for this work. Whether this mineralisation of lithium is economic or not is a question which an interested lithium mining corporation is currently trying to answer. This work establishes background concentrations of lithium and a suite of other metals in the environment surrounding the known lithium mineralisation’s in Ireland, prior to any mining activity. In chapter two the baseline concentration of lithium in the surface and groundwater of the area are established (surface water at = 0.020 and groundwater at = 0.023mg/l). In chapter three lithium baseline concentrations are given for the topsoil and two endemic plant species in the area (i.e. topsoil at = 57.8, Ash at = 43.7 and Ivy at 52.3mg/kg). In chapter four we investigated the potential application of five plant species to agromine lithium. The concept of agromining involves the use of plants to sequester large amounts of metals from the soil with an aim of recovering those metals from the plant tissue. The work is the first of its kind and may set the groundwork for any future research in the subject. Highlights from the work include promising results from both cabbage and rapeseed plants with lithium plant concentrations approaching 3000 mg/kg dry weight.