Evaluation Of Drinking Water From Various Sources
Some sources of water are obvious, like lakes and rivers, while others, like glaciers, are a bit more removed from everyday experience. With so many people living near water, it sometimes seems unlikely that water shortages could be a serious problem. Understanding the sources of water available for human use reveals how limited freshwater actually is. Despite the overwhelming amount of water on earth, very little of it is suitable for consumption. New research and technology are currently seeking answers to this dilemma.
Ground water refers to any source of water that lies beneath the soil layer. Ground water can exist in the soil itself or between rocks and other materials.
Most communities obtain their water from underground aquifers, or rock formations capable of holding large amounts of freshwater. Only 3 percent of the water on earth is considered freshwater, with a mere 30 percent of that small amount being found as groundwater.
Evaluation of Drinking Water from Various Sources Abstract The Objective: The objective of this project is to test for impurities and contaminants of various water sources in order to perhaps prove that bottled water does have more contaminants than other sources.
Pollution, seawater contamination and overuse threaten this valuable resource. Surface Water. Although ocean water makes up nearly 97 percent of all water on earth, it is not a viable source of potable water unless salt and other impurities are removed.
Desalination, the process by which salt is removed from water, is a rapidly growing practice. While salt and other microscopic particles can be removed from water in a variety of ways, the most promising method is through reverse osmosis. This process forces saltwater through filters with microscopic pores that remove salt and other microbes. Reverse osmosis requires large amounts of energy, making it a very expensive process. Ice Caps and Glacial Melting.
AndABSTRACTA comprehensive bacteriological analysis of 525 drinking water samples collected from railway stations, houses, rivers and lakes (surface water), tube wells and open wells was carried out using Manja`s H 2S field test, MTFT (MPN) test, TTC (Eijkman test) and MFT test. Detection efficiency of faecal coliform contamination for H 2S field test (96-97%) was comparable to MPN test and more detection level over that of MFT and TTC. Efficiency of H 2S test varies with the source and decreased with the depth of the source of water. However, the H 2S test, compared to other tests, was more suitable, reliable, inexpensive, easy to perform and useful to detect fecal contamination in drinking water within 24 h, for places where time, man and laboratory facilities are very poor. Howto cite this article:D.H. Tambekar, S.R.
Gulhane and Y.S. Banginwar, 2008. Evaluation of Mofified Rapid H 2S Test for Detection of Fecal Contamination in Drinking Water from Various Sources. Research Journal of Environmental Sciences, 2: 40-45.DOI:URL:INTRODUCTIONStandard methods, which are available for detection of fecal contamination in drinking water, require trained analyst, bacteriological media and other supporting materials and facilities of microbiology Laboratory (WHO, 2002). In 1982, KS Manja (DRDO, Gwalior, India) developed a H 2S rapid field test based on production of hydrogen sulphide by bacteria that are associated with fecal contamination. The H 2S-producing bacteria are invariably present in feces and have very strong correlation between presence of H 2S-producing bacteria and fecal pollution of water. Hence by detecting the presence of H 2S-producing bacteria in water samples, fecal pollution of such water can be deduced.
This rapid fields test needs no technical staff and the cost is lower than conventional bacteriological test for detection of fecal contamination in drinking water (Genthe and Franck, 1999).The H 2S test was evaluated and reported (Sivaborvorn, 1988; Kaspar et al., 1992; Venkobachar et al., 1994; Pillai et al., 1999) favorable for detection of fecal contamination in drinking water from various source, including ground and surface water. Various modifications of H 2S test for detection of fecal contamination at various temperatures and incubation periods indicated that the test could be used in the field without any infrastructure (Rijal et al., 2000; Mark et al., 2002; Pathak and Gopal, 2005; Hirulkar and Tambekar, 2006). Though various people tested the validity of the H 2S test with MTFT or MFT for detection of fecal contamination of drinking water, but further validation and standardization is required by WHO and APHA as an alternative method for use in (WHO, 2002). In present study, composition of original medium was modified by substituting teepol with labolene (neutral pH) and evaluated the efficiency of this test to detect fecal contamination of drinking water from various sources.MATERIALS AND METHODSThe H 2S test was prepared by replacing teepol with bile salt in the medium (Manja et al., 2001). The H 2S medium (1 mL) was added in screw cap 30 mL bottle and sterilized at 121°C for 15 min. To each bottle, drinking water (20 mL) was inoculated for testing its bacteriological quality in duplicate. The bottles were then incubated at room temperature and 37°C for 24 to 48 h.
Multiple Tube Fermentation Technique (MTFT) was performed by nine multiple tube dilution using double and single strength MacConkey medium (APHA, 1998). MFT test by using M-EC test agar (Hi-media Lab. Mumbai) and Eijkman test (detection of thermotolerant coliforms, TTC) by using Brilliant Green Bile Lactose Broth (BGLB) and indole test at 44.5°C were performed for each water sample as per standard protocol.
The study was carried out over a period of four months from July to October 2006 and Water samples (525) collected from railway stations (173); all railways stations of Nagpur Bhusaval division of Central railway, India; houses from Amravati City (101); surface water (river, lake etc., 88), tube well (75) and open (dug) well (88) from salinity affected villages of Amravati district of Maharashtra State (India) were analysed by each of above tests. Blacking in H 2S medium was recorded as positive test after incubation period.
Only MTFT positive (polluted) water samples were further subjected for Eijkman test in BGLB and Tryptone medium at 44.5°C for 24 h and positive results were recorded as gas in BGLB and indole positive. The sensitivity, specificity predictive values and efficiency of H 2S test were calculated as.RESULTS AND DISCUSSIONOut of 525 water samples tested, 413 were polluted by MTFT test (10 coliforms 100 mL -1), 184 by H 2S test in 24 h of incubation, 328 by H 2S test in 48 h of incubation and 151 polluted by MFT and 139 by TTC. However 106 (in 24 h) and 100 (in 48 h) water samples were safe by both H 2S and MPN test (. 2:Efficiency (accuracy) of H 2S test with water fromvarious sourcesThe efficiency of H 2S test either in 24 h or 48 h incubation when compare with standard water quality tests was varies with source of drinking water. When compared with MTFT, it was 70-99% in surface water, 60-88% in open (dug) well water, 41-77% in tube well water, 45-73 in railway station water and 60-67% in house hold water indicating good agreements between these two test for surface, open well and household water. This clearly indicated that more coliforms per 100 mL lead to more accurate H 2S test and good agreement.H 2S test indicated good agreement with TTC (95%) and MFT (66%) in household water. Higher the MPN index, higher the agreement between modified H 2S test, MFT and TTC, indicating fecal thermotolerant coliform always associated with H 2S producing microorganisms.
Thus indicated that H 2S test can detect the fecal pollution efficiently and efficiency of this test was upto 99% and decreased with the depth of the water source. Therefore the test is more reliable for surface, open well and household water where theres direct facal contamination due to human activities.CONCLUSIONSThe H 2S test (48 h incubation) was comparable to MPN method based on presence of thermotolerant coliforms. Thus the H 2S was found to be more suitable, reliable, inexpensive, easy to perform and most useful to detect faecal contamination in drinking water within 24 to 48 h. It also proved suitable to assess of drinking water and useful in routine screening for large number of samples for places where time, man and laboratory facilities are very poor. In principle, the test does not conform to the conventional standards of bacteriological testing of water samples and cannot replaces the conventional MTFT, MFT or TTC test. However, the H 2S test is easy to perform, user-friendly, screening test, suitable for handling by untrained personnel for community participation in monitoring of rural drinking water sources and low cost rapid test, hence recommended for the routine monitoring of water for recent faecal contamination in the field or villages where technical expertise, infrastructure and incubation equipment are not readily available.REFERENCESAPHA, AWWA and WEF., 1998. Standard Methods for the Examination of Water and Wastewater.
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Evaluation Of Drinking Water From Various Sources Of Energy
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Drinking Water Benefits
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