Heavy metals

wi (k)

Unit weightage (Wi)

Standard permissible value (Si)

Pb

1

0.1

10

Cd

1

0.33

3

As

1

0.1

10

Cu

1

0.0005

2000

Zn

1

0.0003

3000

Cr

1

0.02

50

Mn

1

0.0025

400

Fe

1

0.0033

300

S 8

S0.56