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Introduction

The quality of drinking water in Indian cities has deteriorated in the recent years mainly due to growing population, unplanned growth of cities coupled with no proper sewage system leading to poor disposal of the waste water, both from industrial and household activities, Ghazali (1992).

On account of the paucity of open water resources for potable purpose, groundwater resources are being tapped profusely throughout the year. The over use of underground resources has led to number of problems and invites attentions for their conservation and maintenance of their potable quality as most of the ailments in India (70%) such as jaundice, cholera, diarrhoea, dysentery and typhoid etc., are caused by the consumption of polluted water, Rehman (2003). Somashekar et al. (2000) in their study conducted in a rural district of Banglore reported that 80% of wells are unsuitable for potable purpose in terms of hardness, while 50% and 20% were not fit for the drinking purpose on account of magnesium and nitrate respectively. Since no study of such type has been conducted in Bhopal as such the necessity was felt to conduct the work.

Material and Methods

Water samples of various hand pumps and tube wells from fourteen sites were collected in polythene bottles as per the standard procedure and were transported to laboratory for chemical analysis. The chemical analysis was carried out following the methods as given in APHA (1995), pH and conductivity values were measured with portable digital meters-Systronics.

Table 1: Important chemical characteristics of underground water samples.

^{X₁= Ibrahimpura Chowk; X₂= Nadeem road Ibrahimpura; X₃= Bawaria Kala-II; X₄= Narayan Nagar; X₅=6 No. Bus stop; X6 = Baghswania; X₇= Bag Mugalia; X₈= Bawaria Kala-I;X₉= Pipaliya-I; X₁₀= Pipaliya-II; X₁₁= Janghirabad; X₁₂= Ravishankar Nagar; X₁₃= Budhwara;X₁₄= Itwara.}

Table 2: Variation in chemical parameters on average basis in comparison to various standards

^{WHO: World Health Organization; ICMR: Indian Council of Medical Research;BIS: Bureau of Indian Standards; HDL*: Highest Desirable Limit. MPL**: Maximum Permissible Limit.}

Results and Discussion

Determination of chemical characteristics is essential for assessing the suitability of water for drinking purpose. Present work has been compared with the standards laid down by various agencies such as WHO, ICMR and BIS. The results of the present study are given in Table: 1. The observed pH values ranging from 6.2-8 show that the water samples were near neutral to slightly alkaline. These values are within maximum permissible limit prescribed by WHO, ICMR and BIS (Table: 2).

The overall conductivity values ranged from 340-1900µS.The conductivity values of tube wells ranged between 660-920 µS, while, the conductivity value of hand pumps ranged from 340-1900 µS (Table.2). Very high electric conductivity values were recorded in four hand pump samples (Table.1), which might be on account of underground minerals. No prescribed standards are suggested by WHO, ICMR and BIS for electrical conductance of water for drinking purposes, so no comparison can be made from observed values.

水样的TDS值到220不等-1220mg/l. The TDS values of some of the samples (X₁, X₂among tube wells and X₅, X₇, X₁₂, X₁₄among hand pumps) were found to be within the highest desirable limits as per WHO, ICMR and BIS, thus recording that out of 14 samples only six samples were found to be safe for drinking purpose. TDS value of sample X₆was found to exceed even the maximum permissible limit as per WHO.

Total alkalinity values of all the water samples varied from 174-532mg/l. The values exceeded highest desirable limit except one (174 mg/l recorded in sample X₇). In most of the samples (X₂, X₃, X₄,X₅, X₆, X₈, X₉, X₁₁, X₁₃) the total alkalinity values exceeds the maximum permissible limit as per the specification WHO and ICMR So from the alkalinity point of view, quality of water samples of the above mentioned sites belonging to both hand pumps and tube wells is of very poor quality.

The calcium hardness values ranged between 27.75-619.5mg/l.the values of samples X₉and X₁₀exceed the maximum permissible limit as per WHO, ICMR and BIS while in most of the samples calcium hardness values were even below the highest desirable limits even as specified by WHO, ICMR and BIS.

Magnesium hardness values of the samples varied between 22-383.85mg/l. The values of the sample X₃, X₆and X₈exceed the maximum permissible limit set by WHO, ICMR and BIS whereas all other samples have the value within the maximum permissible limit.

Total hardness value varied from136-760mg/l. Total hardness of water samples X₈and X₉exceed the maximum permissible limit according to WHO, ICMR and BIS and the values of remaining twelve samples were within the maximum permissible limit as per WHO, ICMR and BIS.

Chloride content of all the samples ranged from 19.99-350mg/l which is within the maximum permissible limit as prescribed by WHO, ICMR and BIS.

The present study reveals that the water collected from some of the tube wells is comparatively much better in comparison to the water collected from hand pumps.

References

1. APHA. Standard methods for the examination of water and wastewater. American Public Health Association Washington, D.C. (1995).
2. Attiqur Rahman, Assessing water quality from Jal Nigam hand pumps in Aligarh City.Nature Environment and PollutionTechnology,(2003) 2(2), 241 - 244。
3. BIS, Drinking water specification (first revision) First reprint. Bureau of Indian Standards. IS: 10500:1991 (1992).
4. Ghazali, F.A. Poisoned waters, mindless industrialization polluting rivers. Nation and the World, 15^thFeb.(1992) pp. 28-29.
5. I.C.M.R. Manual of standards of quality drinking water supplies. Indian Council ofMedical Research. 2^nded. Special report series No. 44, New Delhi (1975).
6. Somashekar, R.K. Ground water chemistryof Channapatna Taluk (Banglore rural district) Regression and cluster analysis.Journal ofEnvironment and Pollution.(2000) 7(2): 101-09.
7. W.H.O. Guidelines for drinking water quality, W.H.O. Geneva. (1984) Vol. 1.