This study evaluated results obtained from two routinely used sample preparation methods: microwave digestion and lithium fusion. Three different microwave digestion procedures and a lithium metaborate fusion method were examined. Forty trace elements in addition to 16 rare earth elements were determined in three distinct rock types and one standard reference material by inductively coupled plasma-mass spectrometry (ICP-MS). Lithium fusion resulted in excellent recovery of rare earth and some trace elements including Be, V, Sr, U, Hf, Nb and Ta, but the some elements Pb, Cr, Zn were lost. Two of the microwave digestion procedures produced similar results and proved suitable for the determination of most elements in different rock types. In addition, this study examined the potential interferences of the suspected major components (Si, Cl, Sr, Fe and Ba) of the rock on minor elements and the interferences of the light rare earth elements oxides on the heavy rare earth elements. The chemical compositions of three rock types (Volcanic, carbonate and shale) collected from the Nevada Test Site, the Fossil Ridge and Frenchman Mountain were compared. Since the rock type may determine the chemical composition of the associated groundwater, the water collected from springs thought to flow from carbonate, volcanic and shale aquifers were compared with each of the three whole rock chemical compositions
