الفهرس 
Water-Related Diseases
MATERIAL AND METHODSOnly 14 pages are availabe for public view
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Abstract
Water is essential for maintaining life and is considered the most important natural resource. Although human life can exist for many days without food, the absence of water for only a few days has fatal consequences.
The role of sanitation and safe water in maintaining health has been recognized for centuries. The provision of water sanitation and good hygiene services is vital for the protection and development of human resources.
Outbreaks of endotoxin-related illness associated with drinking water have been documented infrequently. This may be due to the fact that many outbreaks of fever-related illness in water are never identified by routine medical and bacteriological analyses and that endotoxins-related fever symptoms are typically short-lived. Few studies have been reported on the usage of endotoxin detection as a monitoring tool for good quality of bottled water.
This study aimed to assess level of bacterial endotoxins in tap and bottled water and compare its concentration with bacterial indicators.
This study was carried out on a total of 120 uncarbonated natural bottled water samples of 4 commercial brands produced in Egypt and were designated A,B,C and D (30 samples each) and 30 carbonated bottled water samples designated as E. These bottles were purchased from several retail outlets in Alexandria. In addition, 59 tap water samples were randomly collected from three districts in Alexandria (El-Amria, Borg El-Arab and West of Alexandria).
The water samples were aseptically collected in sterile wide mouthed ground glass stoppered bottles of 250 ml capacity. A 4-5 DROPs of sodium thiosulphate was added to each bottle prior to sterilization to neutralize the lethal effect of chlorine on microorganisms if present.
Each water sample was accompanied by a sheet including: sampling date, time of collection, sampling site and temperature. All samples (bottled and tap) were vigorously shaken and analyzed within 1-3 hours of collection by the following procedures:
1. Enumeration of HPC using pour plate method.
2. Enumeration of TC and E.coli using MF technique.
3. Detection of P. aeruginosa using P/A technique.
4. Measurment of bacterial endotoxins using LAL assay.
The results of this study can be summarized as follows:
1. According to the Egyptian guidelines, out of the 150 examined bottled water samples; 96 (64.0%) were acceptable and 54 (36.0%) were unacceptable. The corresponding figures for tap water samples were 71.2% and 28.8% respectively.
2. The percentage of bottled water samples that had unacceptable HPC at 22º C and 37º C constituted 28.7% and 34.0% respectively, compared to only 23.7% and 22.0% for tap water samples respectively.
3. The percentage of tap water samples that contained TC constituted 5.1%, while no E. coli was found. Regarding bottled water neither coliforms nor E.coli were detected.
4. Isolation rates of P. aeruginosa from bottled and tap water samples were 1.3% and 1.7% respectively.
5. P. aeruginosa were isolated from brand A only, with a percentage 6.7%.
6. Brand A represented the highest percentage of unacceptable samples 90.0% while all brand D were acceptable.
7. The percentage of unacceptable carbonated water samples was 3.3%.
8. The percentage of unacceptable samples of the unrefrigerated bottles constituted 41.1%, compared to 31.2 % for the refrigerated bottles.
9. All bottled water samples stored for<1 month were bacteriologically acceptable, where all samples stored for > 6 months were bacteriologically unacceptable.
10. Endotoxin concentration in tap water samples varied from 0.0 to 78.3 EU/ml with an average of 31.3 EU/ml, while endotoxin concentration in bottled water varied from 0.0 to 165.7 EU/ml with an average of 29.5 EU/ml.
11. All tap water samples did not exceed the endotoxin acceptable level.
12. The percentage of unacceptable bottled water samples for endotoxin was 7(7.4%), where 4 of these samples were from brand A.
13. Moderate agreement was found between endotoxin concentration and HPC (K=0.711).
It can be concluded from this study that:
1. Bottled water samples were not found to be superior to tap water samples as regards their bacteriological quality; on the contrary tap water was considered to be of better quality.
2. According to the Egyptian standards, brand D was the best brand while brands A and B represented the worst brands.
3. Refrigeration of the bottled water minimizes or maintains the bacterial growth.
4. The presence of elevated HPC and P.aeruginosa may indicate poor GMPs.
5. Measurement of endotoxin levels in addition to bacterial counts might yield a real picture of water quality.