|
Sl.
No.
|
Substance
or Characteristics
|
Requirement
Desirable Limit
|
Undesirable
Effect Outside the Desirable Limit
|
Desirable/
Essential
|
Remarks
|
| 17. |
Mercury
(as Hg) mg/L, Max. |
0.001 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected. |
| 18. |
Cadmium
(as Cd), mg/l, Max. |
0.01 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected. |
| 19. |
Selenium
(as Se) mg/l, Max. |
0.01 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected. |
| 20. |
Arsenic
(as as) mg/l, Max. |
0.05 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected |
| 21. |
Cyanide
(as Cn) mg/l, Max. |
0.05 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected |
| 22. |
Lead
(as Pb), mg/l, Max. |
0.1 |
Beyond
this the water becomes toxic. |
Desirable |
No
relaxation of this limit is allowed to be
tested when pollution is suspected |
| 23. |
Zinc
(as Zn), mg/l, Max. |
5.0 |
Beyond
this limit it can cause astringent taste and
an opalescence in water. |
Desirable |
May
be relaxed up to 10.0. To be tested when pollution
is suspected. |
| 24. |
Anionic
detergents (as MBAS), mg/l, Max. |
0.2 |
Beyond
this limit it can cause a light froth in water. |
Desirable |
May
be relaxed up to 1.0. To be tested when pollution
is suspected. |
| 25. |
Chromium
(as Cr+6) mg/l, Max. |
0.05 |
May
be carcinogenic. |
Desirable |
-- |
| 26. |
Mineral
Oil, mg/l, Max. |
0.01 |
Beyond
this limit undesirable taste and odour after
chlorination takes place. |
Desirable |
May
be relaxed up to 0.03. To be tested when pollution
is suspected |
| 27. |
Residual
free chlorine mg/l, Max. |
0.2 |
-- |
Essential |
To
be applicable only when water is chlorinated.
Tested at consumer end. When protection against
viral infection is required, it should be
min. 0.5 mg/L. |
