Current World Environment

Introduction

Water quality is a terms used to define the physical, chemical biological or radiological characteristics by which a particular type of water may be evaluated to establish its acceptability for various beneficial uses.^2-4

Materials and Methods

All the chemical used were of AR grade. Double distilled water was used for preparation of reagents. Six strategic locations were chosen for the sampling water. Those are Koni Petrol Pump (Station-I), Indira Setu (Station-II), Old Bridge (Station-III), submersible bridge (Station-IV), Kanoi paper Mill (Station-V) and Near Gatora Bridge (Station-VI). Water samples were collected in one-litre polythene bottles previously soaked with 8N.HNO₃ and cleaned with detergent. The samples were acidified with 6N.HNO₃ (8 ml/L) soon after sampling.
 

Table – 1 Click here to view table

Analytical Methods

pH of the sample was measured by pH meter (Orion pH meter model 940). Cd and Pb were determined (after complexation and extraction) by AAS (Varion AA model 220). Conductivity of samples have been measured by Digital conductivity bridge (Systronics-304). The operation conditions for AAS have been described below in the Table 1. Dissolved oxygen (DO) and Biological Oxygen Demand (BOD) were determined by prescribed laboratory titrimetric methods.
 

Figure - 1: Dissolved oxygen at different stations Click here to view figure

Dissolved Oxygen (Wrinklers methds)

300ml sample was taken in BOD bottle, then 2ml. MnSO₄ and 1 ml. Alkaline lodide Azide solution was mixed with it 2ml. H₂SO₄ acid was added and titrated with 0.025 N Hypo, using starch as indicator. The dissolved oxygen was then calculated using standard formula.⁵
 

Figure - 2: Biological oxygen demand Click here to view figure

[1ml of 025 N. Hypo solution = 1mg/l of dissolved oxygen]

Biological Oxygen Demand

Water sample were kept in the dark for five days. The dissolved oxygen was determined using the Winkler’s titration method and calculated BOD using standard formula⁵
 

Table - 2: Indian Standard Specifications for Drinking water is (10500-1083) Click here to view table

Table - 3 : Classification of water quality10 Click here to view table

Chemical Oxygen Demand

Organic substance in the samples were oxidized by K₂Cr₂O₇ in 50% H₂SO₄ at a reflux temperature. Ag₂SO₄ was used as a catalyst. The excess of K₂Cr₂O₇ was titrated with standard Fe^II (NH₄) (SO₄)₂ (hypo) using ferroin as an indicator.

Principle reaction is :
 

 

Figure - 3: Concentration of Pb+2 in mg/l. Click here to view figure

Results and Discusiion

These figure inform about dramatic change in water quqlity parameters. Hence the Arpa river water is rendered unsuitable for drinking in the city area. The Arpa river is shallow but life line of Bilaspur city. Increasing population and rapid industrialization in the last few decades have icreased pollution in the potable rive water. Dissolved oxygen decreases from point no. 1 to 4. Paper mill at point 5, throws chemical containing alkali and plant degradation products. In the present study temperature ranged from 25°C to 29.5°C. The pH value ranged from 6.9 (Location) 8.69 (location 5) of the Arpa river. Location 5 and 6 show higher values than the prescribed limit.⁶
 

Figure - 4: Concentration of Pb+2 in ppm Click here to view figure

Figure - 5: Pb+ levels in mg/I Click here to view figure

Total dissolved solids (TDS) ranged form 230 mg/l (station I) to 1500 mg/l (station 4,5,6). According to and Indian standards as shown in the Table No. 3 TDS should be less than 500mg/l for drinking water (Table No.3). The dissolved oxygen between 4 to 8 mg/l .The standard limit is 7mg/l for drinking water.⁸ The BOD ranged from 20mg/l to 45 mg/l. The standard limit is 30mg/l.⁹ Chemical oxygen demand (COD) was determined by titrimetric method. COD value informs about organic matter present in the drinking water.

Depletion of dissolved oxygen in water supplies can encourage microbial of NO₃^-1 to NO₂^-1 and SO₄^-2 to S^-2 giving rise to odour problem. The Electrical conductivity value ranged between 0.50 to 6.15 × 10^-3 mhos/cm to 6.15 × 10^-3 mhos/ cm in the present work. Higher values are 3.30, 4,5.2×10^-3 mhos/cm at locations 2,3,4,5 and 6 and water is unfit for drinking.

Standard values Pb and Cd concentrations for potable water are 0.01 mg/l and 0.003mg/l. In the present work higher values have been found in the stations 2,3,4,5 and 6. Classification of water quality has been described in the table No.3 below.

Conclusion

Rapid urbanization and increased anthropogenic activities have deteriorated the water quality parameter of Arpa river water. Therefore the pretreatment is essential before supplying for drinking purpose. (This also applies to ground water). Following methods have been suggested as remedial measures.

Remedial Measures
 

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