Standard reference water samples for rare earth element determinations

Standard reference water samples (SRWS) were collected from two mine sites, one near Ophir, CO, USA and the other near Redding, CA, USA. The samples w ere filtered, preserved, and analyzed for rare earth element (REE) concentr ations (La, Ce, Pr, Nd, Sm, Eu, Cd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) by indu ctively coupled plasma-mass spectrometry (ICP-MS). These two samples were a cid mine waters with elevated concentrations of REEs (0.45-161 mug/l) Seven teen international laboratories participated in a 'round-robin' chemical an alysis program, which made it possible to evaluate the data by robust stati stical procedures that are insensitive to outliers. The resulting most prob able values are reported. Ten to 15 of the participants also reported value s for Ba, Y, and Sc. Field parameters, major ion, and other trace element c oncentrations, not subject to statistical evaluation, are provided. Publish ed by Elsevier Science Ltd.