Table 5. Comparison of heavy metal contents in other rivers in Tibet.

Location	Cu	Pb	Zn	As	Mn	Cd	Cr	Ni	Hg	pH
Yellow River	1	0.1	4.4	1.2	3.3	<0.007	1.8	—	—	8.0–8.6
Buha He	1.4	<0.05	3.7	0.9	3.8	N.D.	2	—	—	8.5
Shule He	0.8	0.1	1.5	1.4	6.3	<0.004	2	—	—	8.3–8.8
Lhasa River	2.863	0.056	0.829	3.071	6.237	0.042	3.156	—	0.005	8.8
Heihe River	6.02	6.14	66.70	2.68	46.75	0.65	6.57	20.37	—	8.6–8.7
Gyamaxung-chu	5800	695.67	2454.67	—	1061	2.87	2.30	23.20	—	—

Note: The heavy metal units in the table are all μg/L.