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 HeYangtze 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 km2, 23 060 km2 in Tibet)

The seventh longest river in Asia and the 12th longest in the world (4 500 km, 509 km in Tibet)It drains in total 810 000 km2 (38 300 km2 in Tibet)

Mekong River

The second longest river in Southeast Asia (3 200 km, 1 393 km in Tibet)It drains in total 325 000 km2 (102 500 km2 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, 2 057 km in Tibet) It drains in total 630 000 km2 (240 480 km2 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 (Ca2+, Na+, K+, Mg2+, Cl-, NO3-, HCO3

-, SO4

2-, NH4+, PO4

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 (SiO2)

UNIVERSITY OF EASTERN FINLANDLAEC

Sampling

Data interpretation - TDS in the Tibetan waters

0

50

100

150

200

250

300

350

Salween River

Mekong River

Yangtze River

Yarlung Tsangpo

Europe *Asia *

Africa *

North Americ

a *

South America *

World *

* Calculated according to Wetzel, 1975

TDS

(mg/L)

Water chemistry of the Tibetan rivers

0

10

20

30

40

50

60

70

80

90

100

mg/

L (

EC

in m

S/m

) Tibetan Plateau

World

Mg2+Ca2+ Na+ K+ NO3- HCO3

- SiO2SO42- Cl- EC

Data interpretation- Major ion composition

Ca2+ Mg

2+0 20 40 60 80 100

Na+ + K+

0

20

40

60

80

1000

20

40

60

80

100

Contributors of Salween River Salween River main streamContributors of Mekong RiverMekong River main stream Contributors of Yangtze RiverYangtze River main streamContributors of Yarlung Tsangpo Yarlung Tsangpo main stream

0 20 40 60 80 1000

20

40

60

80

100

SO42-

0

20

40

60

80

100

HCO3-

Cl-

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: 113-121 (2011)

Source: Huang et al. River Res. Applic. 27: 113-121 (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: 6242-6254 (2009).

Source: Huang et al. River Res. Applic. 27: 113-121 (2011)

Mining in Gyama

Four mines existed

during the field work,

but more mines are

under constructionOnly sedimentation

ponds to treat effluentsGyama 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: 6242-6254 (2009).

Source: Huang et al. River Res. Applic. 27: 113-121 (2011)

Data interpretation - Major controlling factor in Yarlung

Tsangpo

0,40,30,20,10,0-0,1-0,2

0,4

0,3

0,2

0,1

0,0

-0,1

-0,2

-0,3

PC 1 (37%)

Li

Ti

Mo

S

MnFe As

AlTDS

SiO2

SO4

NO3

Cl

HCO3

K

Na

Mg

Ca

Turbidity

EC

pH

Temp.

PC

2 (

17%

)

Factors affecting water qualityof Tibetan rivers

Natural processes Mining activities Municipal wastesClimate change

Thank you for your attention!

Mika.Sillanpaa@lut.fi