4.1 RESULTS
All laboratory findings are available in hard copy by folder and the data analyses are available on Microsoft excel.
4.1.1 BACTERIOLOGICAL ANALYSIS
A. Distribution of faecal coli forms and total coli form organisms in water sources
This study showed that drinking water sources of the municipal drinking water were contaminated with faecal coli forms and total coli forms (Fig 1). Microorganisms were detected in four sources of municipal drinking water sources of Addis Ababa. The overall bacterial result showed that the least results were shown in public taps and reservoirs while the highest results were shown in springs and wells.
Finally, 106 (6%) samples of all public taps, 26 (6%) samples of reservoirs, 34 (24%) samples of springs and 115 (21%) samples of wells were contaminated with bacterial contamination.
B. Distribution of faecal coli forms and total coli forms by week in wet season of Addis Ababa
The municipal drinking water was contaminated with both faecal coli forms and total coli forms throughout the sampling rounds and all weeks of the wet season. The highest faecal coli forms was observe in week 1 and 5 while the highest total coli form was observed in week 11 while (Figure 2). There was a general slight increment of Total coli forms from week 1 to week 13 of the wet season while the number of faecal coli forms was slightly decreasing from week 1 to week 13 of the wet season.
Table 1 The total summary results of four sources and all collected samples of public municipal drinking water samples in Addis Ababa (June to August 2016)*
Sample Source
|
Total Negative
|
Total Positive
|
Total Coli forms
|
Faecal coli form Positives
|
Total Samples
|
Public Taps
|
1727 (59%)
|
106 (6%)
|
78 (4%)
|
28 (2%)
|
1833
|
Reservoirs
|
403 (94%)
|
26 (6%)
|
22 (5%)
|
4 (1%)
|
429
|
Springs
|
109 (76%)
|
34 (24%)
|
21 (15%)
|
13 (9%)
|
143
|
Wells
|
431 (79%)
|
115 (21%)
|
83 (15%)
|
32 (6%)
|
546
|
Total
|
2670 (90%)
|
281(10%)
|
204 (7%)
|
77 (3%)
|
2951
|
* All laboratory data are available with the principal investigator
4.1.2 PARASITOLOGICAL TEST RESULTS
In this study, the parasitological examinations of twenty five selected reservoirs were negative for parasites by conventional microscopic examination. Generally, the results of selected service reservoirs were free from parasite species.
4.2 DISCUSSION
This study revealed that about 10% of all bacteriological samples were positive for total coli forms and faecal coli forms (Table 1). This finding confirms previous similar studies conducted in different parts of the world that drinking water samples had been contaminated with microorganisms such as total coli forms with the percentages of 100%, 90%, 70%, more than 51%, 33.33%, 23% and 12% (41, 20, 35,4, 37 and 18), faecal coli forms with the percentages of 100%,73.94%, 70%, 61.1% and 40% (12, 25, 38, 35, 21 and 20), both total and faecal coli forms together with the percentages of more than 50%, 50%,33.33%and 31.2% (40, 13, 23 and 36) and Escherichia coli with the percentages of 80%, 78.1%, 70%, 27.1%, 20% and significant number (19, 15, 35, 5,20 and 11).
This study revealed that 7% of the municipal drinking water samples were contaminated with total coli forms during the study period (Table 1). Coli form bacteria were detected in the sample tested. Sample is considered unsatisfactory for drinking water purposes. Similar studies were conducted in Peshawar, Pakistan by Ahmad et al in 2013, by Bhatnagar et al in 2012 in Jaipur, by Metgaud et al in 2011 in Karnataka and by Rana et al in 2014 in Bhilai and El badawy et al in 2013 in Tabuk, India had showed that 70%, 66.67%, 33.33%, 23% and 12% of drinking water samples were positive for total coli form bacterial contamination respectively (35, 14, 23,37and (18).
This study also revealed that 3% of the municipal drinking water samples were contaminated with faecal coli forms during the study period (Table 1). Faecal coli form bacteria were also detected in the samples tested. Sample is considered unsatisfactory for drinking water purposes. Presence of faecal coli form bacteria indicates fecal contamination of the water supply has occurred. Similar studies conducted by Misra et al in Assam, India in 2010, by Ahmad et al in Peshawar, Pakistan in 2013, and by Stenger et al in 2012 in Bo, Sierra Leone had showed that 78.1%, 70% and 61% of drinking water samples were contaminated with Escherichia coli and faecal coli forms bacterial contamination respectively (15, 35 and 21).
In developing countries particularly in Ethiopia, drinking water is obtained from different sources. Such as taps, reservoirs, springs and wells. This study revealed that samples collected from the municipal drinking water sources of this study area were contaminated with microorganisms during the study period. Accordingly, 6% of drinking water samples collected from public taps were positive for bacterial groups; and 6% of drinking water samples collected from service reservoirs were positive for bacterial groups (Table 1). Similar studies conducted by Bhatnagar et al in 2012 in Jaipur, in Lahore, Pakistan by Siddiqi et al in 2010, by Traistaruin Cyprus in 2011, by El badawy et al in 2013 in Tabuk of Saudi Arabia had showed that 66.67%, 37.2%, 14%, 12% of bacteriological samples were contaminated with total coli forms (14, 22, 39, and 18). Other similar studies had showed that most samples collected from reservoirs were both total and faecal coli forms positives whereas; in some reservoirs the contaminations were with similar bacterial groups (13 and 20).
This study also revealed that all samples collected for parasitological quality and safety assessment were negative for parasitological species. Similar study by El badawy et al in 2013 in Tabuk, Saudi Arabia had showed that parasitological examination revealed that giardia cysts were detected in 25% of water samples and C. parvi oocysts were detected in 16.6 % of water samples by both microscopy and ELISA methods (18). This was may be due to the water sources differences where wells and surface water samples were used and/ or ELISA method while our sample sources were from treated service reservoirs and direct microscopy respectively. Similar study had showed by Rostami et al, 2015 in Shush, Iran 40% samples were infected with at least one of the active stages of parasitic organisms; out of these, 28.7% the protozoa and 18 11.2% were infected with the worm process of living organisms. According to the study 6.3% were related to the parasite Entamoeba histolytica. Therefore, prevalence of Entamoeba histolytica was 6.3% of drinking water in the city of Shush (43). Even though, our study was similar methodology to the report from Shush, Iran, the differences were sample sources. According to Gobena et al in 2015 water analysis demonstrated that all water sources from Dire Dawa were contaminated by pathogenic parasites. From the recapitulate results, above (83.34%) of unprotected wells water sources, (50%-100%) from unprotected springs and protected wells, (33.34%-66.67%) from protected springs and (50%) from tap water were positive both for the presences of Cryptosporidium oocysts and Girdia lamblia cysts (44). Generally, samples collected for parasitological tests revealed that all of them were free from parasitic species.
4.3 CONCLUSION
It was concluded that the contamination detected in the water sources were due to improper or insufficient chlorination, random and technical faults during operation of service reservoirs, poor handling and accidental contamination of public taps. On the other hand, the contamination detected in most springs and wells were majorly due to the rainy season of the study area and/ or study period as during the wet season heavy rain and flood can easily carry contaminants of human and animal wastes from the environment and contaminate the springs and wells.
Finally, this study concluded that most Addis Ababa city drinking water sources had acceptable quality and were safe for bacteria and parasite to drink.
4.4 RECOMMENDATION
The population of the city has to protect and/ or minimize the taps from microbiological contamination can be caused by human and animal contact. Not fixing, tying and hanging ropes, plastic tubes and pieces of clothes and plastics minimize the harboring and growing of microorganisms on faucets and nozzles. Therefore, the population has to practice keeping the faucets and nozzles neat and clean. The pipes of some city places are older and highly prone to breakage and leakage. Therefore, regular monitoring and maintenance is very important.
Protecting springs and wells of the drinking water sources by building safe them from human, animal, heavy rain and flood contact. Therefore, implementation is the critical strategy. Regular monitoring of drinking water quality is essential as it is an important factor that has a direct effect on human health. Operational research need to be conducted to check whether the trend of water quality and safety practices at utility, community and household levels are implemented.