Chemical characterization of stream water on the Tibetan Plateau.

Stream water samples were obtained in duplicate at 8 sites on the Tibetan Plateau (29 degrees 15 ' 31 degrees 53 'E, 85 degrees 03 ' -91 degrees 48 'N) during the GAME-Tibet IOP project from May 7-22, 1998, as well as one sample from a salt lake at a north-eastern site. Ion chromatography, atomic absorption spectrometry, ICP/MS and chemiluminescence were applied to determine the major and minor chemical species. The pH, EC and concentrations of Cl-, SO42-, Na+, K+, Ca2+ , Mg2+, SiO2, F-, Sr2+, Ba2+, Ni2+, Cu2+ NO3-, NH4+, DON are shown. The concentrations of SO42-, Sr2+ and Ba2+ were found to be higher in the western part of the sampling sites, while those of NO3- , DON and Mn were higher at eastern sites. The concentration of Ca2+ was fairy uniform, while those of Na+, K+ and SiO2 ranged widely without any clear geographical tendencies.