Bio-Mapping of Rivers, March 1999

WATER QUALITY CRITERIA (WQC) FOR EVALUATION OF WATER BODIES

Primary Water Quality Criteria (PWQC)

Central Pollution Control Board has derived Primary Water Quality Criteria as required in the designated best uses of river stretches (Table 1.a). Based on the long term water quality data generated over the years, 13 heavily polluted and 26 medium polluted river stretches has been identified. The critical pollutants identified for the polluted river stretches are dissolved oxygen, bio-chemical oxygen demand and total coliforms. In most of the rivers these parameters are not adequate to indicate the overall health of a water body. The bio-maps based on bio-assessment clearly depicts, the stretches where the deterioration of water quality has occurred, which envisage actions for improvement.

Outcome of primary water quality criteria

Table 1.a Primary water quality criteria for various uses of fresh waters, as laid down by the Central Pollution Control Board

 

S. No.

Characteristics

A*

B*

C*

D*

E*

1.

Dissolved oxygen (DO), mg/l, Min.

6

5

4

4

-

2.

Biochemical oxygen demand (BOD) mg/l, Max.

2

3

3

-

-

3.

Total coliform organism** MPN/100 ml, Max.

50

500

5,000

-

-

4.

pH value

6.5-8.5

6.5-8.5

6-9

6.5-8.5

6.5-8.5

5.

Free ammonia (as N), mg/l, Max

-

-

-

1.2

-

6.

Electrical conductivity, micromhos/cm, Max.

-

-

-

-

2,250

7.

Sodium adsorption ratio, Max.

-

-

-

-

26

8.

Boron, mg/l, Max

-

-

-

-

2

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