S/No

Standard Name

Standard Symbol

Concentration (ppm)

1

Copper

Cu

2

4

8

2

Zinc

Zn

1

2

4

3

Cobalt

Co

7

14

21

4

Nickel

Ni

7

14

28

5

Manganese

Mn

2.5

5

10

6

Chromium

Cr

2

4

8

7

Lead

Pb

12.5

25

50