δ11B, Rare Earth Elements, δ37CI, 32Si, 35S, 129I

Boron isotope analyses have been increasingly used in hydrogeological studies during the past decade, due to recognition of large variations in the natural isotopic composition of boron (at least 90%_o), and the development and refinement of mass spectrometric techniques (e.g., Spivack and Edmond, 1986; Vengosh et al., 1989; Eisenhut et al., 1996). The wide range in isotopic composition of the boron sources in water resources, both natural (e.g., sea water, fossil brines, hydrothermal fluids) and anthropogenic (sewage effluents, boron fertilisers, fly ash leachate), as well as the reactivity of boron with the aquifer matrix, make boron a useful natural isotopic tracer in groundwaters.