Research articles

By Dr. Swaminathan Rajan , Dr. K.l. Lalhmingchhuansangi
Corresponding Author Dr. Swaminathan Rajan
Post Graduate and Research Department of Zoology, Pachaiyappa's College - India 600030
Submitting Author Dr. Swaminathan Rajan
Other Authors Dr. K.l. Lalhmingchhuansangi
PG and Research Department of Zoology, Pachaiyappas College, Chennai-30, India., - India


Drinking Water Quality? Microbiology of Drinking Water? Chlorination of Water & Health

Rajan S, K. A Study Of Drinking Water Quality Of Aminjikarai, J.J. Nagar, Valluvarkottam and Vadapalani Area Of Chennai, Tamil Nadu. WebmedCentral ECOLOGY 2012;3(8):WMC003655
doi: 10.9754/journal.wmc.2012.003655

This is an open-access article distributed under the terms of the Creative Commons Attribution License(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submitted on: 17 Aug 2012 10:00:24 AM GMT
Published on: 18 Aug 2012 06:29:01 PM GMT


Water quality is closely linked to water use and health of the people. According to WHO, about 80% of the diseases of human beings are related to water quality only. In order to assess the drinking water quality of Chennai, the water samples were collected from the source water (Red Hills Lake), treated water at Kilpauk water treatment plant and two water Trunk Mains which supply Aminjikarai, J.J.Nagar and Valluvarkottam, Vadapalani area of North Western part of Chennai including the dead-end of distribution systems. The present study was undertaken during the period of December 2008 to May 2009. A total number of six stations were fixed for drawing the water samples in which Station I and II remains the same for both the trunk Mains. The 1st Trunk Main supplies water to J.J.Nagar through Aminjikarai from Kilpauk water treatment plant. The 2nd Trunk Main supplies water to Vadapalani through Valluvarkottam from Kilpauk water treatment plant. Water samples were analyzed for physico-chemical and microbiological quality. The results indicate that the water supplies of Chennai are suitable for drinking as per the guidelines. However, the TDS level had exceeded the permissible limit in one station and the level of Iron was higher than the desirable limit in most of the stations of water supply in the study area. The contamination of microbial flora of water was also reported occasionally.


The 2001 census reported that 68.2% of house holds in India have access to safe drinking water. According to latest estimates, 94% of the rural population and 91% of the people living in urban areas have access to safe drinking water. While accessing drinking water continues to be a problem, assuming that it is safe in challenging by itself.   It has been estimated that globally 1.20 billion people become stick annually due to poor quality of drinking water (Leslie, 2000). Further, according to WHO, 80% of diseases of human beings are caused through medium of water and 1800 million man working days are lost in India due to such water born diseases (Rural drinking water, 2000). The above facts emphasize the importance of water quality management. Hence the presence study of drinking water quality of Two Trunk Mains of Chennai drinking water distribution system is investigated.

The city of Madras is located at about 13o N, 80o E on the South East Coast of Indian Peninsula. According to 2011 census, it has the population of 4.6 million. Because of the geographical location of this city, Madras is subjected to extreme variation in annual rainfall. The North East Monsoon (NE) is responsible for the major portion of the annual precipitation total. Failure of this N.E. Monsoon can have a devasting impact on Madras. Red hills reservoir is the prime source of drinking water for the city since 1860’s. it is from the reservoir that Chennai Metro water supply (CMWS) drains 315 mld of water daily for the city’s drinking water supply. Following treatment at Kilpauk water works, water is supplied to different parts of the city by various Trunk Mains which runs several kilometres to supply water by covering 184 km2 areas. In the present study, the North Western part of Chennai viz. Aminjikarai, J.J.Nagar and Valluvarkottam, Vadapalani area have been selected.

Water quality deserves special attention because of its implication for affecting the public health and the quality of life. Physical and chemical characters of water are changed due to the addition of organisms to water. These changes are harmful for the health and thus reduced the usefulness of water. Water supplies once considered pure are found to have contaminants. One cannot expect pure water, but everyone requires safe water. Micro-organisms enter the water supply in several different ways. In congested centre, water supplies get polluted by domestic and industrial wastes.

Sewage containing human excreta, however, is the most dangerous material that pollutes water. In 1986, Rajan investigated the Drinking water quality of Chennai which includes the microbiological and level of Trihalomethanes (THMs) in drinking water (Rajan et. al., 1990 & Rajan et. al., 2004 a). The source, Red Hills Lake is getting increasingly polluted by taking bath, washing clothes, bathing cattle and defecates by the growing population on its periphery. Though the water is treated before being supplied to households, the pollution at the source remains a matter of concern. During the treatment of water, chlorination has been carried out to control bacterial population. However, as the water is supplied to distant parts of Chennai, it results in revival of bacterial population and sediment accumulation (Rajan S, 1986 & Rajan et. al., 1990). Therefore, an attempt has been made in the present study to assess the water quality of the source, treated water at Kilpauk water works and two water Trunk Mains, one Trunk Main which supplies water to J.J.Nagar area through Aminjikarai and second Trunk Main which supply water to Vadapalani area through Valluvarkottam pumping station.

Materials and Methods

A total number of 36 water samples were collected from 6 stations from the selected Trunk Mains of Chennai during the study period (Dec. 2008 to May 2009). The details of sampling points chosen for collecting water samples are given in Table 1. Samples were brought to the laboratory immediately under cold conditions and analyzed as per the procedures described by APHA (1998).


Results and Discussion

The results of the physico-chemical and microbiological water qualities of Chennai are shown in Table 2 to 7. The water samples showed odourless, colourless and clear in the two Trunk Mains except at Station IV in the month of May, the water sample was slightly turbid.

Turbidity of the water samples ranged from 0.2 to 14.8 NTU in the 1st Trunk Main and 0.1 to 5.3 NTU in the 2nd Trunk Main. The reported values are within the prescribed limit (BIS, 1991 & WHO, 1999) except at Station I and IV in the month of May. Silts and clays from soil erosion and industrial wastes cause water to be turbid. Turbid water is abrasive to pipes, pumps and turbine blades (Ramakrishnan, 2006). Often protected public water supplies are found to contain excess turbidity due to impurities in bleaching powder and prevailing of vacuum in main during non-supply hours.

The TDS values ranged between 220 to 340mg/l in the 1st Trunk Main and 176 to 378mg/l in the 2nd Trunk Main. The TDS of drinking water of Chennai is found to be within the desirable limit. The TDS of drinking water sources of Tiruvannamalai were within the permissible limit (Ramakrishnan et al, 1991). The excess of TDS may cause gastro-intestinal irritation.

The pH of drinking water varied from 6.09 to 8.18 in the 1st Trunk Main and6.07 to 8.18 in the 2nd Trunk Main. The acidic pH observed in the present study was below the permissible limit of 6.5 (BIS; 1991). Similar acidic pH was reported by Periasamy (2006) at Chembrambakkam Lake, Chennai. The alkaline pH of present study was within the desirable limit of 8.5 (BIS; 1991). Alkaline pH was also reported by Vaisya (1991) in Chittora reservoir.

The total alkalinity varied from 80 to 155mg/l in the 1st Trunk Main and 72 to 135mg/l in the 2nd Trunk Main and was within the desirable limit of 200 (BIS; 1991). Nagarathna (2002) reported 4 to 28mg/l of alkalinity in Yelawala Lake (Mysore). Excess alkalinity gives bitter taste to water. High alkalinity is not harmful but delimits water for domestic use.

Hardness is mainly due to the presence of Calcium and Magnesium compounds. Hardness varied from 81 to 140mg/l in the 1st Trunk Main and 78 to 140mg/l in the 2nd Trunk Main. It was within the desirable limit of drinking water standard as recommended by BIS, 1991(300). Excessive dumping of garbage, industrial wastes and sewage discharge may also contribute the high total hardness. Shivastava (1993) reported that the high hardness in water is due to weathering of rocks. The level of Calcium concentration varied from 19 to 42mg/l in the 1st Trunk Main and 19 to 34mg/l in the 2nd Trunk Main. It was within the desirable limit of 75 (BIS; 1991). The amount of Magnesium varied from 7 to 19mg/l in the 1st Trunk Main and 7 to 13mg/l in the 2nd Trunk Main. It was within the desirable limit of 30 (BIS; 1991).

The level of Sodium concentration varied from 24 to 58mg/l in the 1st Trunk Main and 20 to 74mg/l in the 2nd Trunk Main. It was within the desirable limit of 200mg/l (WHO; 1999). The primary source of Sodium in natural water is the weathering of Plagioclase Felspar. Further, clay minerals may release large quantities of exchangeable Sodium.   

The amount of Potassium varied from 2 to 6mg/l in the 1st Trunk Main and 2 to 7mg/l in the 2nd Trunk Main. Potassium is derived during the process of weathering of rocks. Aschengrau et al (1993) reported that the frequency of central nervous system defect was increased when the level of Potassium increased in water. Hence the level of potassium in drinking water is of health concern.

The level of Iron was 0.03 to 1.53mg/l in the 1st Trunk Main and 0.11 to 0.79mg/l in the 2nd Trunk Main. The level of Iron had exceeded the desirable limit of drinking water standard of 0.3(BIS; 1991 and WHO; 1999) in most of the stations. Iron was found to exceed the permissible limit in different source types in Bankura district, West Bengal (Singh et al, 1993). The higher value of Iron in the water is due to the rusting of Iron pipes laid in the city nearly ten decades ago. Large quantities of Iron cause unpleasant taste and favour the slimy growth of Iron Bacteria. Therefore, the water supplied to public will have unpleasant taste and odour. Further, more than about 0.5ppm of Iron stains clothes and utensils reddish brown.

The level of Ammonia varied from 0.09 to 0.81mg/l in the 1st Trunk Main and 0.02 to 0.71mg/l in the 2nd Trunk Main. Li (1994) reported that the chemical indicators for water pollution includes Ammonia, Nitrite, humic acid, suspended substances, COD and BOD are related to liver cancer.

The level of Nitrite varied from 0.01 to 0.04mg/l in both the Trunk Mains. The level of Nitrite was within the desirable limit of 3 (WHO; 1999).

The level of Nitrate ranged from 2 to 7mg/l in both the Trunk Mains. It was within the desirable limit of 45 mg (BIS, 1991) and 50 mg (WHO, 1999). Nitrates in natural water come from organic sources or industrial and agricultural chemicals like fertilizer. Nitrate encourages growth of organisms like algae that cause undesirable taste and odour and leads to eutrophication of lake (Rajan, 1986; Rajan et al, 1990; Rajan et al, 2004a; Rajan et al, 2004b). Concentrations in excess of 45ppm of Nitrate may cause Methaemoglobinemia in infants (blue babies).

In the present study, the level of Chloride concentration varied from 32 to 72mg/l in the 1st Trunk Main and 22 to 76mg/l in the 2nd Trunk Main. It was within the desirable limit of 250 (BIS; 1991 and WHO; 1999). Chlorides cause corrosiveness and hardness.

The level of Fluoride varied from 0.16 to 0.49mg/l in the 1st Trunk Main and 0.16 to 0.45mg/l in the 2nd Trunk Main. It was within the desirable limit of 1 (BIS; 1991) and 1.5 (WHO; 1999). Fluoride in small amount in drinking water reduces the incidence of tooth decay during the period of enamel calcification. However, it may cause mottling of teeth depending upon the concentration of Fluoride, the age of the child and the amount of water consumed. Fluoride in excessive concentration may cause dental defects, affect bone structure and in acute cases cause fluorosis.

In the present study, the level of Sulphate varied from 6 to 31mg/l in the 1st Trunk Main and 6 to 20mg/l in 2nd Trunk Main. It was within the desirable limit of 200 (BIS; 1991) and 250 (WHO; 1999). The level of Phosphate varied from 0.02 to 0.54mg/l in the 1st Trunk Main and 0.01 to 0.47mg/l in the 2nd Trunk Main. Holas et al (1998) reported that the total input of Phosphorus into the Zelivka drinking water reservoir came mainly from surface inflows due to rainfall and bottom sediments.

The level of Silica varied from 1.36 to 14.76 in the 1st Trunk Main and 1.34 to 12.68 in the 2nd Trunk Main. Silica forms hard scales in pipes and boilers but does not affect water for domestic purposes.

A point of interest is that in the present study, the concentration of Chloride, TDS, Alkalinity, Hardness, Calcium, Sodium, Sulphate, Fluoride, Phosphate and Silicate are found to be increasing towards the dead-end of the distribution system and there is sediment accumulation.

The total Bacteria in the 1st Trunk Main and 2nd Trunk Main varied from 20 to 450/ml and 30 to 450/ml respectively. Most of the time, the bacterial colony was absent in the distribution system. The highest count was observed at the source, which was due to bathing of human, washing of clothes, disposal of sewage and inflow of rain water. The occurrence of bacterial population in the distribution stations may be due to local contamination or low amount of chlorination in water, cross connection of pipes, seepage of sewage, sediment accumulation in pipes and revival of bacterial population. Anwar et al (1999) reported that maximum bacterial contamination was observed in water from domestic pumps followed by tap water in rural areas of Punjab and tap water in Lahore.

The total Coliform, faecal Coliform and faecal Streptococci were detected only in the source water and the values were 90 to 280/100ml, 60 to 140/100ml and 30 to 90/100ml respectively and their absence in the distribution system is due to effective treatment of  water by chlorination. Abo-Amer et al (2008) reported that in Egypt, the untreated water samples (hand pumps) were slightly contaminated by faecal Coliforms. Tambe et al (2008) reported that in Maharashtra, out of 313 samples of different sources, 49.8% were polluted whereas 45.9% of samples from piped water supply were polluted. Aziz (2005) reported that in Pakistan, most of the drinking water supplies were faecally contaminated which resulted in high incidence of water borne diseases. In Bangladesh, faecal Coliform was low in water at the supply point but significantly higher in water samples stored in households (Hoque et al, 2006). Jensen et al (2004) reported that faecal contamination levels in household water containers were generally high even when the source water was of good quality in Punjab and Pakistan. Hence, in comparison of above reports, Chennai drinking water is found to be bacteriologically safe after chlorination.


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