The Analysis of Picogram Quantities of Rare Earth Elements in Naturual Waters -- Determination of 56 Trace Elements in Three Aquifer- Type Rocks by ICP-MS and Approximation of the Relative Solubilities for These Elements in a Carbonate System by Water-Rock Concentration Ratios -- Rare Earth, Major, and Trace Element Geochemistry of Surface and Geothermal Waters from the Taupo Volcanic Zone, North Island New Zealand -- The Aqueous Geochemistry of the Rare Earth Elements and Yttrium. Part 13: REE Geochemistry of Mine Drainage from the Pine Creek Area, Coeur d'Alene River Valley, Idaho, USA -- Lanthanide Elements in Alteration Minerals as a Guide to Transport Phenomena in the Vadose Zones of Continental Tuffs -- Origin of Rare Earth Element Signatures in Groundwaters of South Nevada, USA: Implications from Preliminary Batch Leach Tests Using Aquifer Rocks -- Rare Earth Element Contents of High pCO2 Groundwaters of Primorye, Russia: Mineral Stability and Complexation Controls -- Geochemistry of Rare Earth Elements in Groundwaters from a Rhyolite Aquifer, Central México -- Rare Earth Element Concentrations, Speciation, and Fractionation along Groundwater Flow Paths: The Carrizo Sand (Texas) and Upper Floridan Aquifers -- Rare Earth Elements (REE) and Nd and Sr Isotopes in Groundwater and Suspended Sediments from the Bathurst Mining Camp, New Brunswick: Water-Rock Reactions and Elemental Fractionation. Rare Earth Elements in Groundwater Flow Systems is the first volume of its kind entirely focused on the geochemistry of the lanthanide series elements in groundwater/aquifer environments. Consisting of ten chapters, each of which is an original, peer-reviewed contribution by some of the leading researchers in the study of the low-temperature geochemistry of rare earth elements, the volume addresses analytical techniques, water-rock interactions, aqueous complexation, and the reactions/processes that influence these heavy metals along groundwater flow paths.