Determination of Water Quality of Areas near by Amadalavalasa Mandal in Srikakulam District A.P.

 

A.V.L.N.S.H. Hariharan*, J.V.S.K.V. Kalyani  and K. Manasa

Department of Chemistry, GIT, GITAM University. Visakhapatnam – 530 045, India.

*Corresponding Author E-mail: ahharan@rediffmail.com

 

Physico – Chemical analysis of well and bore well water samples was carried out from seven sampling stations from the Areas near by Amadalavalasa Mandal in Srikakulam district for six months during 2012 pre monsoon and post monsoon periods. The present study aimed to calculate Water Quality Index (WQI) in order to assess the suitability of water for drinking purposes.  The results obtained on WQI from different sampling stations were found to be varied from 38.076 to 44.645. The WQI values indicate that the water maintains suitability for human consumption.

 

INTRODUCTION:

Water is one of the most important natural resources for all the living organisms.  The three percent of global fresh water is large enough to meet the requirements of the man for million of years. In India the major source of water used to meet the domestic agriculture and industrial needs is the ground water. Due to rapid industrialization the limited fresh water resources are getting polluted. In recent survey it is observed that only 12% of people get safe drinking water¹. Inadequate management of water resources has directly or indirectly resulted in the degradation of hydrological environment². Therefore, a continuous periodical monitoring of water quality is necessary so that appropriate steps may be taken for water resource management practices. The present investigation was carried out to assess the suitability of ground water recourses of Amadalavalasa Mandal in Srikakulam District.

 

MATERIALS AND METHODS:

The seven sampling stations selected for the analysis are:  S1 – Thogaram, S2 – Dusi RS, S3 – Kalivaram , S4 – Muddhada peta, S5 – Belamam, S6 – Boddepalli and S7 – Raagolu.

 

Samples were collected in sterilized bottles using the standard procedure for grab (or) catch samples in accordance with standard methods³.

 

The analysis of various Physico–Chemical parameters namely–pH, Turbidity, Color, Total Alkalinity, Total Hardness, Chlorides, Nitrates, TDS, DO, BOD were carried out–as per methods described⁴.  All the chemicals and reagents used in the study were of analytical grade.  Double distilled water was used for the preparation of solutions.

 

RESULTS AND DISCUSSION:

Results obtained on various Physico–Chemical parameters along with Water Quality Index (WQI) for the samples (only with maximum values) are presented in Tables – 1and 2.

 

Temperature: 

A rise in temperature of water leads to the speeding up of the chemical reactions in water as it affects bio – chemical reactions in aquatic organisms. It reduces the solubility of gases and amplifies the tastes and odors. The average temperature of the present study ranged between 27.49 and 28.04°C.

 

P^H:

It is known that pH of water does not cause any severe health hazard, however higher pH results in the formation of trihalo methanes which are toxic⁵. The pH values of the present investigation were within the ICMR Standards⁶ (7.0 – 8.5).

 

Electrical Conductivity:

It is an important parameter for determining the water quality for drinking and agricultural purposes. Many dissolved substances may produce aesthetically displeasing color, taste and odour.  The values obtained are in the range of 1.2 and 1.8  mmhos/cm.

 

Table – 1;   Physico – Chemical Parameters of Water Samples collected (2012)

 

Total Dissolved Solids (TDS):

The TDS values for ground water ranged from 429.8 to  528.0  mg/L as per the standards.

 

Dissolved Oxygen (DO): 

A minimum of dissolved oxygen of 4 to 5 mg per lit is desirable for the survival of aquatic life. Presence of DO in the water may be due to direct diffusion from air and photosynthetic activity of autotrophs⁷.

 

Alkalinity: 

Most of the alkalinity in natural water is formed due to dissolution of Carbon dioxide in water.  Carbonates and bicarbonates, thus formed are dissolved to yield hydroxyl ions. Large amounts of alkalinity imparts a bitter taste to water. In the present investigation the Total Alkalinity (TA) of the water samples ranged between 86.8 and 118.2  mg/l.

 

Hardness: 

Hardness is a measure of the ability of water to cause precipitation of insoluble calcium and magnesium salts of higher fatty acids from soap solutions. Water with a total hardness of 500mg/lt is considered hazardous to human health⁸. The hardness values of the present study were found to range between 178.5 and 234.0 mg/L.

 

Chlorides: 

Chlorides occur in all types of natural waters. The high concentration of chloride is considered to be an indication of pollution due to high organic waste of animal origin⁹. The values obtained in the present study varied between 65.2 and 101 mg/L.

 

BOD: 

BOD (Bio – Chemical Oxygen Demand) is the parameter used to assess the pollution of surface and ground waters.  The values are within permissible levels.

 

Nitrate: 

Nitrate is the most important nutrient in an ecosystem.  Generally water bodies polluted by organic matter exhibit higher values of Nitrate.  In the present investigation the values showed low concentrations of nitrates (< 1.36 mg/lt).

 

Water Quality Index (WQI):

Overall the quality of water   for a given specific purpose is  indicated in terms of index number, called WQI.  It is defined as a rating reflecting the composite influence of different water quality parameters which were taken into consideration for the calculation of Water Quality Index (WQI).  The indices are among the most effective ways to communicate the information on water quality trends to the general public or to the policy makers and in water quality management.  Mostly it is done from the point of view of its suitability for human consumption.

 

The calculation of WQI was made using weighed Arithmetic Index Method¹⁰ in the following steps:

Let there be water quality rating (q_n) corresponding to n^th parameter is a number reflecting relative value of this parameter in the polluted water with respect to its standard permissible value. 

q_n values are given by the relationship: q_n = 100 (v_n – v_i) / (v_s – v_i)

Where v_n= Standard value, v_s = Observed value and v_i = Ideal value

In most cases v_i = 0, except in certain parameters like pH, Dissolved Oxygen etc.

Calculation of Quality Rating for pH and DO (v_i ≠ 0)

For pH    q_pH = 100 (v_pH – 7.0) / (8.5 – 1.0)   and               For DO   q_DO = 100 (v_DO – 14.6) / (15.0 – 14.6)

 

Table – 2 Standard Values of Water Quality Index (WQI)

WQI Values	Rating
0 – 25	Excellent
26 – 50	Good
51 – 75	Bad
76 – 100	Very Bad
100 and above	Unfit

 

Calculation of Unit Weight:

The Unit Weight (Wn) to various water quality parameters is inversely proportional to the recommended standards for the corresponding parameters.

Wn = K / S_n           Where

Wn = Unit weight for nth parameter, K = proportionality constant S_n = Standard permissible value for nth parameter

 

The Unit Weight (Wn) values in the present study are taken from¹¹ and WQI is calculated by the following expression:

              n                    n

WQI =  ∑  Qn x Wn  / ∑Wn

             n-1                 n-1

 

WQI values obtained were compared¹² as mentioned in Table 2 (standard values)for rating the water and its quality.

Table3. Water Quality Index of well and bore well waters in the Areas near by Amadalavalasa Mandal in Srikakulam District.

Parameter	ICMR Standard	Unit Wt. (Wn)	S1	S2	S3	S4	S5	S6	S7
pH	7.74	0.07164	6.8123	7.2380	7.6082	7.1084	6.9141	6.9696	7.0732
T.D.S	500	0.00100	0.0926	0.0872	0.1027	0.094	0.0859	0.1027	0.1056
T.H.	200	0.00167	0.1824	0.1563	0.1954	0.1559	0.1816	0.1718	0.1490
D.O.	5	0.10030	8.6258	10.03	9.2276	8.6258	9.027	9.6288	9.2276
B.O.D.	5	0.10030	2.4072	2.2066	2.006	1.8054	2.2066	1.8054	2.4072
Chloride	250	0.00200	0.0522	0.0659	0.0788	0.0808	0.07424	0.0636	0.0582
Total Alkalinity	120	0.00417	0.3016	0.3930	0.2384	0.3121	0.4048	0.3458	0.4107
Nitrate	45	0.01111	0.02419	0.0222	0.02419	0.02765	0.0311	0.03357	0.0232
Iron	0.3	1.6666	1.1107	2.2213	2.7767	1.666	2.2213	--	1.1107
Wn	--	--	1.99128
Qn	--	--	19.6081	22.4205	22.2579	19.8761	21.1466	19.1213	20.6654
WQI	--	--	39.0469	44.645	44.322	39.5788	42.1088	38.076	41.1506

 

The values of WQI (in the present investigation) are less than 50 (38.076-44.645) as given in Table 3.

 

CONCLUSION:

On the basis of the result obtained the WQI values are less than 50. It can be concluded that the water is safe and hence suitable for human consumption.

 

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Received on 25.09.2013          Modified on 12.10.2013

Accepted on 16.10.2013         © AJRC All right reserved