Introduction

Water is essential to life on planet earth. Humans generally consume from 2 to 4 L water per day [01]. Potable or drinking water is defined as having a satisfactory quality in terms of its physical, chemical, and bacteriological parameters so that it can be securely used for drinking and cooking [02]. Human population growth employs several important and various pressures on the quality and the quantity of drinking and freshwater resources and on the access to them [03]. The evaluation of the microbiological quality of drinking water aims to protect consumers from illness due to consumption of water that may contain pathogens such as bacteria, viruses, and protozoa, and thus to prevent water-borne disease outbreaks [04]. The most common and widespread health risks associated with drinking water in developing countries are of biological origin. The WHO estimates that about 1100 million people globally, drink unsafe water, and the greater part of diarrhoeal disease in the globe (88%) is attributable to insecure water sanitation, and hygiene [05]. In developing countries, poor water quality is one of the most important risk factors for child mortality mainly through diarrhea. In India, about 10% of the rural and urban population do not have access to safe drinking water, thus increasing the likelihood of spread of waterborne diseases [03].

The WHO Guidelines for Drinking-Water Quality recommend that Faecal Indicator Bacteria (FIB), preferably E. coli or alternatively Thermo-Tolerant Coliform (TTC), should not be detectable in any 100 ml drinking water sample [06]. Coliforms belong to the family Enterobacteriaceae and include the genera of Escherichia, Enterobacter, Klebsiella, Citrobacter, Kluyvera, Leclercia, and some members of the genus Serratia [04].

Materials And Methods

Sample collection

One liter of water samples were collected during November 2014 to February 2015 from the groundwater around the Rural Vicinities of HRBR Layout. Three samples per sampling point were collected. One liter sterile bottle was used to collect and transfer the sample to the laboratory.

Water quality analysis

parameters [Temperature, pH, Total Dissolved Solids (TDS), Total Solid (TS), Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Dissolved Oxygen (DO)] and Biological Parameters [Biochemical Characterization Tests, Gram Staining, Most Probable Number (MPN) and Motility] by using standard methods from ‘Standard Methods for the Examination of Water and Wastewater’ [07]. The media used for the bacteriological analysis of water include Brilliant Green Lactose Broth (BGLB) and Eosin Methylene Blue Agar (EMB).

Data analysis

Data for Physicochemical [Temperature, pH, TSS, TDS, TS, DO, BOD and COD,] and Biological [Gram Staining, Motility and Biochemical Characterization Tests and MPN] components in water samples were recorded and analyzed for. Mean and standard deviations were calculated from the results of the three samples per sampling point for the physical parameters. Water Quality Results obtained were compared with the Approved Guidelines and Standard Limits provided WHO (2011) [08], BIS (2012) [09] and CPCB (2008) [10]. The MPN result was compared with FDA’s Bacterial Analytical Manual [11]. The pure cultures of the bacterial isolates were subjected to various morphological and biochemical characterization tests to determine the identity of the bacteria isolates with reference to Bergey’s Manual of Determinative Bacteriology [12].

Results

Physicochemical parameters

The Results are shown in Figure 1 & 2. Figure 1 shows the Temperature of study area varied between 26.33 ± 0.30 – 28.47 ± 0.45 OC. The pH value of study area varied between 6.47 ± 0.06 – 8.37 ± 0.06. DO, BOD and COD values of the water sample used. The DO values varied between 5.07 ± 0.11 – 8.83 ± 0.05 mg/L. BOD readings ranged between 1.17 ± 0.05 – 4.57 ± 0.29 mg/L. COD values ranged between 8.67± 0.11 – 42.00 ± 0.17 mg/L.

Figure 2 shows the TDS values in the study area stretched between 199.33 ± 2.07 – 819.33 ± 2.01 mg/L. The values of TSS in the studied area ranged between 20.67 ± 3.06 – 393.33 ± 5.37 mg/L. The TS values in water samples were found to be in the range of values range 294 – 956.34 mg/L.

Biological parameters

The Biological Parameters are shown in Figure 3 and Tables 1. Figure 3 shows the MPN Index in the studied area was found to be in the range of 03 – 93 MPN per 100 ml. The isolates which were identified after biochemical characterization was shown in Table 1. A total of six bacterial strains were isolated when Gram-staining showed gram-negative with rod-shaped and motility was seen in three (3) organisms. Biochemical analysis of the isolates indicated that:

i. Enterobacter spp.: Positive (VP, Citrate, Oxidase, Catalase), Negative (Indole, MR) and TSI [Butt/Slant/Gas] (K/AG: K = Alkaline/A = Acidic /G = Gas Production)

ii. Escherichia spp.: Positive (Indole, Catalase, MR tests), Negative (VP, Citrate, Oxidase) and TSI (A/AG).

iii. Klebsiella spp.: Positive (VP, Citrate, Catalase), Negative (Indole, MR, Oxidase) and TSI (A/KG).

iv. Salmonella spp.: Positive (MR, Citrate, Catalase), Negative (Indole, VP, Oxidase) and TSI (K/KH2S: H2S = H2S Production)

v. Shigella spp.: Positive (Indole, MR, Catalase), Negative (VP, Citrate, Oxidase) and TSI (A/A)

vi. Yersinia spp.: Positive (Indole, MR, Catalase), Negative (VP, Citrate, Oxidase) and TSI (K/K)

Image 1

Figure 1: Physicochemical parameter: temperature, ph, bod, cod and do.

Image 2

Figure 2: Physicochemical parameter – tss, tds and ts.

Image 3

Figure 3: Biological parameter: most probable number (mpn).

Table 1: Biological parameter: gram staining and biochemical reaction.

Isolate 1 2 3 4 5 6
Gram Stain Rod (-) Rod (-) Rod (-) Rod (-) Rod (-) Rod (-)
Motility + + +
Indole Test + + +
Methyl Red Test + + + +
Voges Proskauer + +
Citrate Test + +
Catalase Test + + + + + +
Oxidase Test +
TSI K/AG A/AG A/KG K/KH2S A/A K/K
Organism Enterobacter.spp. Escherichia.spp. Klebsiella.spp. Salmonella spp. Shigella.spp. Yersinia spp.

Key:

+ = Organism was Positive for the Test

– = Organism was Negative for the Test

A = Acidic

K = Alkaline

G = Gas Production

H2S = H2S Production

Discussion

Physicochemical parameter

The temperature value of water sample from the study area is lower than the prescribed limit by WHO i.e. 30.0 OC. Muyima and Ngcakani [13] showed that high temperature can favor the growth of organisms in water sources. The pH value of study area was within the prescribed limit by WHO, BIS and CPCB (6.5-8.5) which indicates that it can be used as drinking water. Although pH usually has no direct impact on water consumers, it is one of the most important operational water-quality parameters. Careful attention to pH control is necessary at all stages of water treatment to ensure satisfactory water clarification and disinfection. For effective disinfection with chlorine, the pH should preferably be less than 8 [14].

All Twenty (20) sampling points showed higher DO values than the prescribed limit by WHO (5.0). While according to the BIS and CPCB, only S02 and S05 showed the low DO values below 6.0 while the rest is above. The dissolved oxygen content of water is influenced by the source, raw water temperature, treatment and chemical or biological processes taking place in the distribution system. Depletion of dissolved oxygen in water supplies can encourage the microbial reduction of nitrate to nitrite and sulfate to sulfide. It can also cause an increase in the concentration of ferrous iron in solution, with subsequent discoloration at the tap when the water is aerated [06]. The high concentration of DO imparts good taste to water. In a research conducted by Krishnan et al. [15] around Sivakasi found that dissolved oxygen in their water samples to be 8.33mg/ml and 7.41mg/ml; also, suggested the reason for the low dissolved oxygen content was due to decomposition of organic matter, which can indicate a pollution load in the water. Thus, the deficiency of the oxygen in the water can be a shelter for bacteria and other pathogens, which are anaerobic.

All samples revealed that the BOD values were below the approved limit by WHO (6.0). However, according to the CPCB, ten (10) water samples (S01, S02, S03, S04, S05, S07, S08, S15, S17, and S19) were below the limit (2.0), the rest were high. Only five samples (S01, S02, S03, S15, and S17) were with BIS limits (3.0). Groundwater with a high value of BOD is due to microbial activity related to the dumpsites; and, water with high COD values indicates that there is inadequate oxygen available in the water sample [16]. The depletion of oxygen in the water samples is due greatly to microbial activities related to the dumpsites [17].

The TDS values in the study area, 8 samples [S02, S04, S09, S11, S13, S14, S16, S17, and S19] showed higher TDS values than the prescribed limit by WHO (i.e. >500), but they are within the permissible limit according to BIS & CPCB (500-2000). High values of TDS in water are generally not harmful to human beings, but the high concentration of these may affect persons who are suffering from kidney and heart diseases [18]. A high content of dissolved solids elevates the density of water, influences osmoregulation of freshwater organism, reduces the solubility of gases [like oxygen] and reduces the utility of water for drinking, irrigation and industrial purposes [19].

Biological parameters

The analysis of biological parameters is shown in Figure 3 and Table 1. Figure 3 shows the MPN Index according to WHO and BIS Guidelines, none of the water is safe to be used as drinking water (i.e. 0 MPN/ 100 ml). However, based on CPCB Guidelines, only 4 samples (S01, S08, S14, and S16) cannot be used for drinking purposes, i.e. ˃50 MPN per 100 ml, which belong to Quality Class B, thus can be used for Outdoor Bathing (Organised) and recreational purposes. However, the rest belong to Quality Class A (<50). Well-water is usually contaminated by surface waters, especially during the rainy season and inadequate attention is paid to the environmental sanitary qualities of these wells [20]. The microbial contamination of ground water is due to the presence of biodegradable organic matter in wastewater discharges from domestic and industrial effluents [21]. However, drinking water contaminated with these bacteria can cause gastrointestinal illness including diarrhea and nausea, which might even lead to death. These effects may be more severe and possibly life-threatening for babies, children, the elderly or people with immune deficiencies or other illnesses [22]. Table 1 shows the biochemical characterization result; a total of six bacterial strains were isolated and identified as Enterobacter spp., Escherichia spp., Klebsiella spp., Salmonella spp., Shigella spp. and Yersinia spp.

Conclusion And Recommendation

Groundwater samples collected in the Rural Environs of HRBR Layout, Bangalore revealed the presence of Coliforms and other enteric bacteria which is indicative of the poor quality of water. The water samples were found beyond the acceptable limits of WHO and BIS with at least one of the parameters is more than the acceptable limit of WHO and BIS. The MPN value ranged between of 03 – 93 MPN per 100 ml but based on the MPN Mean Value (27.525) and Confidence Interval (± 12.16527) which indicates an overall low MPN value in the study area. Conversely, the CPCB limit for MPN index of <50 can be acceptable if the further treatment like Shock Chlorination Treatment is applied to these sources. According to WHO, BIS and CPCB Guidelines, the water cannot be used as drinking water unless with proper treatments such as the purification and disinfection as to control the bacterial contamination which increasingly being recognized as an issue and of public health importance. Prakash and Somashekar [23] recommended that the public should be made aware of the water quality importance and hygienic conditions before use. Also, it is necessary to implement certain remedial measures. Thus, Regular check-up of the water quality can help to prevent waterborne diseases. Also, as suggested by Ganglia et al. [24], the government should intensify the efforts in the monitoring the water with a view to making potable and wholesome water to the public. To this end, keeping the water sources safe by properly constructed fences, regular maintenance, and supervision of water sources. It is also recommended that owners of groundwater sources, on regular basis disinfect their water sources via Shock Chlorination Treatment. And the proper addition of chlorine to the water and proper disposal of wastes are recommended.

Acknowledgements

The authors’ wishes to recognize the students and staff of the Department of Microbiology and Biotechnology, Bangalore City College, India for their support during the study. We also like to express gratitude to Mrs. Muktamala Kalita, Mrs. M.S. Devika and Mr. Rupesh Sharma for their stimulating discussions, support, teamwork, and solidarity during this investigation. The authors show appreciation to the benevolence of Dr. B. Lakshma Reddy (Former Principal), Dr. Somali Ghosh (Current Principal) and T. Prasad Rao, Director of Bangalore City College, Bangalore, India for their kind help and cooperation throughout the study. The authors’ wish to acknowledge the assistance provided by Dr. (Mrs.) Habiba I. Atta, Department of Microbiology, Ahmadu Bello University, Zaria, Nigeria during the preparation of this manuscript.