MenuISSN (0970-2083)
ISSN (0970-2083)
R.B. Barabde1* and Y.S. Patil2
1Department of Environmental Science, Shri D. M. Burungale College of Science and Arts, Shegaon, Dist. Buldana(M.S.), India
2Department of Microbiology, Shri D. M. Burungale College of Science and Arts, Shegaon, Dist. Buldana(M.S.), India
Received date: 29 September, 2012; Accepted date: 22 November, 2012
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In the present study, physico-chemical and microbiological characteristics of different sources of surface and groundwaters in Shegaon town were determined during February 2012. The objective of the study was to assess the suitability of water for human consumption and other domestic purposes. Water samples from three different densely populated localities were collected and analysed for various parameters using standard methods. The physico-chemical parameters of home well water were satisfactory whereas bore well water exhibited all the values as exceeding maximum permissible limit with a few exceptions of sulphate and dissolved oxygen in bore well water . The microbiological analysis revealed that with the exception of bore well water, all other waters fail to satisfy the prescribed standards set for drinking water. Therefore, the study revealed that the entire water samples investigated in the present study failed to qualify the prescribed standards for drinking water either in the physico-chemical aspects or in the microbiological aspects or both.
Water quality, Ground water, Surface water, Drinking water standards.
Water is one of the essential natural resources for existence and development of life on the earth. Surface and ground waters are the major sources to meet out the entire requirement. However, several factors like industrial and domestic wastes, discharge from agricultural practices, land use practices, rainfall pattern and infiltration rate, geological formation, etc. can affect water quality in a region (APHA 1975). The quality of water is getting vastly deteriorated mainly due to unscientific waste disposal, improper water management and carelessness towards the environment. This has led to the scarcity of potable water affecting human health (Agarkar and Thombre, 2005). Increased anthropogenic activities in and around the water bodies can damage aquatic systems and ultimately microbiology and the physico-chemical properties of water. According to WHO (1984) 30 to 80% human diseases occurred due to impurities in water. Traditionally, the microbiological quality of drinking water is assessed by monitoring non-pathogenic bacteria of faecal origin (Rompre et al. 2002). Before water can be described as potable, it has to comply with certain physical, chemical and microbio- logical standards to ensure that it is palatable and safe for drinking and other domestic purposes (Tebutt 1983).
Shegaon is a densely populated city in Buldana district in Maharashtra, which is reeling under acute shortage of potable water, especially during summer season, despite having a number of surface and groundwater re¬sources. The present situation in Shegaon attracts the attention to the urgency for investigating the causes and sug¬gestion remedies. In the present study, an attempt has been made to analyse the physico-chemical as well as the microbiological parameters of different water resources available in Shegaon, to see whether these water bodies are suitable for drinking and for other beneficial purposes.
Sampling : The water samples were collected from three different selected regions of Shegaon during the month of February 2012. The location and source of water samples are given in Table 1.
Table 1
The water samples were collected in high grade plastic bottles of one litre capacity. Before collection, the plastic bottles were rinsed with distilled water and then thrice with respective water sample. During collection, care was taken to avoid trapping of air within the bottle by completely im¬mersing the bottle within the respective water sample until the bottle is completely filled in with the water sample.
Parameters analysed: The samples collected were brought to the laboratory and analysed for pH, electrical conductivity (EC), dissolved oxygen (DO) and total dissolved solids (TDS) immediately. Other physico-chemical parameters like colour, odour, taste, turbidity, total hardness (TH), total alkalinity, biochemical oxygen demand (BOD), calcium, chloride, fluoride, magnesium, sulphates, iron and nitrates were analysed within 36 hrs of collection. Standard methods were adopted for the analysis of water samples (APHA-AWWA-WPCF 1989).
For microbiological examination, samples were collected in 250 mL sterile bottles, and analysis was carried out within 6 hours of sample collection using standard methods outlined in BIS (1981). The parameters studied include total plate count (TPC), total coliform bacteria and faecal coliforms (E. coli).
Comparison with BIS and WHO standards
The physico-chemical parameters analysed for water samples were compared with BIS (1992) for drinking water and microbiological parameters with WHO standards (1996) for drinking and bathing water. The data provided in Tables 2 and 3 is an average of three samples collected from three different areas under study.
Table 2
Table 3
Colour, taste and odour
All the water samples were found to be colourless. Regarding taste, water sample W2 tasted salty. The odour of all the samples was not objectionable.
pH
As the pH is related to a variety of different parameters, it is not possible to determine whether pH has a direct relationship with human health, but it is argued that pH has an indirect effect as it can affect water treatment processes (Aramini et al. 2009). In the present study the range of pH of different water samples was from 6.8 to 7.5 and all were (Table 2).
Total hardness
Total hardness of different water samples in the present study varied from 71.67 mg/L to 8600 mg/L. Generally, the hardness of water bodies increases as the concentration of calcium and magnesium salt in water increases, especially during summer season due to excessive evaporation. The maximum hardness was observed in water sample collected from bore well (W2) which was 8600 mg/L. This value is much higher than the maximum permissible limit prescribed by BIS (1992). The remaining water sample Wl showed hardness level well within the desirable limit.
Turbidity
According to BIS (1992), the desirable limit of turbidity in drinking water is 5 NTU and a maximum permissible limit is extended up to 10 NTU. The study showed that turbidity value range from 1 NTU to 4.67 NTU. Therefore, all the water samples were well within the desirable limit. The minimum value of turbidity was recorded in water samples collected from home well, whereas the maximum in bore well water.
Iron
The concentration of iron (as Fe) in different water samples varied from 0.41 mg/L to 28.44 mg/L (Table 2). With the exception of sample Wl, all the water samples have iron concentration much above the maximum permissible limit for consumable water, whereas Wl has a value within the maximum permissible limit but above the desirable limit (0.41 mg/L). The intake of large amount of iron through drinking water can cause haemochromatosis, a condition in which normal regulatory mechanisms do not operate effectively, leading to tissue damage as a result of the accumulation of iron (Dillman et al. 1987). Besides this, when iron concentration in the domestic water supply exceeds permissible limit, it becomes objectionable for a number of reasons that are indirectly related to health (Cohen et al. 1960).
Chloride
Chloride is one of the important indicators of water pollution. The value of chloride concentration in water samples W2 under study was too much higher than the maximum permissible limit. It was 10800.50 mg/L in W2. With respect to water samples Wl the chloride concentration was satisfactory as it lies within the desirable limit of BIS drinking water specification, and were 80.22 mg/L. Sources of chloride pollution in water include fertilizers, sewage, effluents, farm drainage, salt and human and animal wastes. High chloride content can cause high blood pressure in people.
Nitrates
The high concentration of nitrates in drinking water is toxic (Gilli et al. 1984). It is regulated in drinking water primarily because high levels can cause methaemoglobinaemia or “blue baby” disease (Mccasland et al. 1985).
Sulphate
Sulphate content of water samples varied from 4.98 to 12.01 mg/L. all the samples were within the desirable limit. Sulphate above the permissible limit may cause gastrointestinal disorders and diarrhoea in human beings (Prasad et al. 2008).
Fluoride
The desirable limit for fluoride in drinking water is 1mg/L and the maximum permissible limit is 1.5 mg/L (BIS 1992). The excessive amount of fluoride in drinking water can cause fluorosis having disfigurement of teeth and deformities of bones (Kulshreshtha et al. 2004). The concentration of fluoride in the water samples varied from 0.02 mg/L to 0.12 mg/L. Therefore, all the water samples have fluoride well within the desirable limit.
Calcium and magnesium
The values of calcium and mag¬nesium in the water samples varied from 17.8 mg/L to 2100.33 mg/L and 1.95 mg/L to 633.09 mg/L respectively. Water samples Wl have acceptable value. Venkata et al. (2006) reported high positive correlation between TDS-Mg, TH-Ca and TH-Mg. The present study also supports this observation, as there is a positive correlation between the values of magnesium, calcium, TDS and total hardness in different samples.
Total alkalinity
Alkalinity of water is related to the actual number of base components and can be thought of as the intensity of the pH. Alkalinity values were recorded in the range of 6.4 mg/L to 13.63 mg/L. Minimum was noticed in bore well water. As per the BIS standards all the values were well within the desirable limit (Table 2). If the alkalinity is low it indicates that even a small amount of acid can cause a large change in the pH.
Total dissolved solids (TDS)
Total dissolved solids of the water samples were in the range of 170 to 1070 mg/L. TDS is an important parameter for drinking water and water to be used for other purposes. According to BIS (1992), water containing TDS value up to 500 mg/L is considered desirable and a maximum permissible limit of 2000 mg/L under unavoidable situations. In the present investigation the water sample Wl showed a range satisfactory and within the desirable limit. The water sample W2 recorded maximum TDS value which is too higher than the maximum permissible limit and are not at all suitable for human consumption.
Biochemical oxygen demand (BOD)
BOD is the amount of oxygen required by the living organisms engaged in utilization and ultimate destruction or stabilization of organic matter in water (Hawkes, 1963). It is an important indicator of water pollution. BOD value of water samples in the present study varied from 2.57 to 17.96 mg/L. As per BIS the maximum desirable limit of BOD for drinking water is 5 mg/L. Here, it is observed that the BOD value of water sample W2 is above the maximum desirable limit, and are 17.96 mg/L. The higher BOD values of this samples clearly indicate pollution and imply high demand for oxygen to support life processes which may be attributed to the percolation of wastewater loaded with biodegradable material.
Dissolved oxygen (DO)
Generally, an increased values of BOD and COD indirectly indicate decrease in DO values. Deficiency of DO gives bad odour to water due to anaerobic respiration of organic matter (Sallae 1974). In the present investigation, with the exception of bore well water (W2), DO values of W1 water sample were comparatively lower and the higher value of DO in water sample W2 may be because of comparatively low organic matter content.
Electrical conductivity (EC)
EC measures the ability of water to conduct an electrical current, and it is directly related to TDS (Aydin 2007). The present study showed that EC values of various samples range from 154.66 to 3376 μmhos/ cm. Water samples Wl and W2 exhibited a reasonable values. The higher values of these samples may be due to high TDS value and the higher concentration of ionised substances present in the samples due to pollution by industrial effluents, domestic wastes, agricultural water, etc. (Aramini et al. 2009). It clearly indicates that samples W2 is unfit for human consumption.
Microbial status
An estimation of bacterial production is a crucial step in understanding quantitatively the function and contribution of bacteria in material cycling within the given aquatic habitats (Azam et al. 1990). Assessment of indicator bacteria namely coliform bacteria is a convenient way to evaluate potability and sanitary condition of water bodies. E. coli and Enterococcus species are traditionally used as hygiene indicator bacteria, and methods for their detection are essential for drinking water regulations all over the world.
As per the results of the present study shown in Table 3, the total bacterial load as evident from total plate count (TPC), bore well water (27 x 102/mL) and home well water (10 x 102/mL). The total coliform count per 100 mL of different water samples ranged from 0 to 113 MPN/l00mL. Coliform bacteria will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms could be in the water system. The water samples collected from bore well showed no coliform count of other water samples, home well were found to fall in higher range than the standard limit for drinking water. Water sample Wl were identified as having the presence of faecal coliform bacteria E. coli. There was no count for Escherichia coli in water sample W2. Confirmation of faecal coliform bacteria or E. coli in a water sample indicates recent faecal contamination of either human or animal origin, which may pose an immediate health risk to anyone consuming the water (Okonko et al. 2008). Therefore, water sample Wl give clear indication of poor water quality as they are exceeding the drinking water permissible microbiological counts suggested as per BIS (1992) and WHO (1996) standards.
As per the suggested WHO (1996,1998) values of total coliform bacteria and E. coli per 100 mL water for the purpose of bathing and swimming (Table 4), the water samples Wl and W2 are safe for bathing purposes as their microbial values are lying within the guide value. Both total coliform and E. coli count exceeded guide value but lying within the mandatory value.
Table 4
The high level of many physico-chemical characteristics of water sample (W2) or microbiological parameters (Wl) or both together render all the water samples unfit for human consumption though they can be used for other purposes. The water should meet the different quality speci-fications depending on the particular use. The microbiological and physico- chemical quality adversely affected the quality of various water sources of Shegaon. The sources of pollution include agricultural practices, infiltration of irri¬gation water, infiltration of sewage effluents, construction activities, farm animals, septic tank, etc. Therefore, people in these areas have high potential risk of getting waterborne or sanitization related diseases under situations when they are forced to use these resources. Therefore, it is recom¬mended that water from these sources is to be used for drinking only after pretreatment like boiling, chlorine disinfection, filtration, reverse osmosis, electrodialysis, etc. based on the situation demand. In conclusion, effective preventive measures are to be taken immediately to save these water resources of Shegaon as it is an area of faster development and dense population.
Desirable limit (DL); maximum limit (ML). All parameters are expressed in mg/L with the exception where colour in hazen units, turbidity in NTU and electrical conductivity in ^mhos/cm.
It is reported that groundwater is often contaminated due to ni¬trogenous fertilizers and manures, and also often accompa ¬nied by pesticides used in agriculture (Munsuz & Unver 1995). It is also reported that nitrate concentration depends on the activity of nitrifying bacteria which in turn get influ¬enced by presence of dissolved oxygen. In the present study values of nitrates indicate that with the exception of water sample W2, all other water samples have nitrate content well within the desirable limit. W2 sample exhibited a value of 1087 mg/L which is many times higher than the maximum permissible BIS guideline value of 100 mg/L.
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