Water Quality of the Yarlung Tsangpo (Brahmaputra) Huang Xiang and Mika Sillanpää November 19th, 2011, New Delhi International conference of ”River Waters: Perspectives and Challengies for Asia”

Huang He Yangtze River Mekong River Salween River Irrawaddy Yarlung Tsangpo Ganges Indus Water Tower of Asia

Yangtze River  The longest river in Asia and the third longest in the world (6 300 km, 509 km in Tibet)  It drains in total nearly 1/5 of China (1.8 million km 2, km 2 in Tibet)

 The seventh longest river in Asia and the 12 th longest in the world (4 500 km, 509 km in Tibet)  It drains in total km 2 ( km 2 in Tibet) Mekong River

 The second longest river in Southeast Asia (3 200 km, km in Tibet)  It drains in total km 2 ( km 2 in Tibet) Salween

Yarlung Tsangpo  The largest river on the Plateau  Known as Brahmaputra downstream in India, it becomes the fifth largest river in the world (3 350 km, km in Tibet)  It drains in total km 2 ( km 2 in Tibet)

Objectives -To assess temporal and spatial variations of chemical composition of the Yarlung Tsangpo -To address possible mechanisms governing the spatial variation of the water chemistry -To identify potential sources of contamination

Sampling preparations  Total of 35 quality parameters were under taken in consideration: Water temperature, pH, electrical conductivity (EC) and turbidity Major ions (Ca 2+, Na +, K +, Mg 2+, Cl -, NO 3 -, HCO 3 -, SO 4 2-, NH 4 +, PO 4 3- and F - ) Trace elements (Al, As, Ag, Cu, Fe, Li, Mn, Mo, Ti, Zn, Cd, Co, Cr, Ni, Pb and Hg) Total dissolved sulphur (S), -phosphorus (TDP), - nitrogen (TDN) and -silica (SiO 2 )

UNIVERSITY OF EASTERN FINLAND LAEC Sampling

Data interpretation - TDS in the Tibetan waters * Calculated according to Wetzel, 1975 TDS (mg/L)

Water chemistry of the Tibetan rivers Mg 2+ Ca 2+ Na + K+K+ NO 3 - HCO 3 - SiO 2 SO 4 2- Cl - EC

Data interpretation - Major ion composition

Source: Huang X. Water Quality in the Tibetan Plateau: Chemical Evaluation of the Headwaters of Four Major Asian rivers”, dissertation, University of Eastern Finland, Finland, 2010.

Source: Huang et al. River Res. Applic. 27: (2011)

UNIVERSITY OF EASTERN FINLAND LAEC No systematic water quality assessment over the Plateau! Current state As (246 µg/L)

Source: Huang et al. Sci Tot. Env. 407: (2009).

Source: Huang et al. River Res. Applic. 27: (2011)

Mining in Gyama  Four mines existed during the field work, but more mines are under construction  Only sedimentation ponds to treat effluents  Gyama stream drains into the Lhasa river, which is a tributary to Yarlung Tsangpo

Cu, Pb, Zn, Fe, Cr, Mo,Mn and Al

Why Tibetan waters - pressures on Tibetan waters

Source: Huang et al. Sci Tot. Env. 407: (2009).

Source: Huang et al. River Res. Applic. 27: (2011)

Data interpretation - Major controlling factor in Yarlung Tsangpo

Factors affecting water quality of Tibetan rivers  Natural processes  Mining activities  Municipal wastes  Climate change

Thank you for your attention!