REEVALUATION AND EXTENSION OF THE SCOPE OF ELEMENTS IN US GEOLOGICAL SURVEY STANDARD REFERENCE WATER SAMPLES

More than 100 US Geological Survey (USGS) Standard Reference Water Sam ples (SRWSs) were analyzed for numerous trace constituents, including Al, As, B, Ba, Be, Bi, Br, Cd, Cr, Co, Cu, I, Fe, Pb, Li, Mn, Mo, Ni, Rb, Sb, Se, Sr, Te, TI, U, V, Zn and major elements (Ca, nag, Na, SiO2 , SO4, CI) by inductively coupled plasma mass spectrometry and inducti vely coupled plasma atomic emission spectrometry. In addition, 15 USGS SRWSs and National Institute of Standards and Technology (NIST) stand ard reference material (SRM) 1641b were analyzed for mercury using col d vapor atomic fluorescence spectrometry. Also USGS SRWS Hg-7 was anal yzed using isotope dilution-inductively coupled plasma mass spectromet ry. The results were compared with the reported certified values of th e following standard reference materials: NIST SRM 1643a, 1643b, 1643c and 1643d and National Research Council of Canada Riverine Water Refe rence Materials for Trace Metals SLRS-1, SLRS-2 and SLRS-3. New concen tration values for trace and major elements in the SRWSs, traceable to the certified standards, are reported. Additional concentration value s are reported for elements that were neither previously published for the SRWSs nor traceable to the certified reference materials. Robust statistical procedures were used that were insensitive to outliers. Th ese data can be used for quality assurance/quality control purposes in analytical laboratories.