DOI: https://doi.org/10.21203/rs.3.rs-1627382/v1
Background: Water of poor quality can cause water borne diseases by bacteria, viruses, protozoa and parasites. It has been frequently described responsible for millions morbidity and mortality. Therefore, quality and safety status of municipal drinking water of Addis Ababa should be regularly monitored in sustainable manner.
Objective: The aim of this study was to assess the bacteriological and parasitological quality and safety status of treated and non-treated municipal drinking water sources in Addis Ababa city.
Methodology: A cross-sectional study was carried out on drinking water sources such as public taps, reservoirs, springs and wells managed by Addis Ababa Water and Sewerage Authority (AAWSA). 125ml drinking water of each 2951 samples were collected from all water sources and analyzed for bacteriological by Presence/ Absence (P-A) culturing method and 11L drinking water of each were collected from 25 selected reservoirs for parasites identification by direct microscopy.
Results: This study revealed that there were 10% of all samples were positive for bacteriological parameters done by presence-absence method. Consequently, 7% and 3% were positive for total coli forms and faecal coli forms respectively. On the other hand, all parasitological tested samples from selected reservoirs were free from intestinal parasites.
Conclusion: It was concluded that most Addis Ababa city drinking water sources had acceptable quality and were safe to drink. Samples were contaminated with fecal coli forms & total coli forms during the study period. It needs continuous screening and treating water sources to utmost important for prevention and control of infectious diseases caused by water transmitted pathogens.
Microorganism contamination of drinking water has been caused serious illnesses and associated mortality worldwide (1). It serves as a mechanism to transmit communicable diseases such as diarrhea, cholera, dysentery, typhoid and guinea worm infection (2). In the developing world, diseases associated with poor water and sanitation still have imposed economical development in addition to threaten million lives (3).World Health Organization estimated that in 2008 diarrheal disease claimed the lives of 2.5 million people (2). In 2013, there were nearly 1.8 million deaths mainly with diarrhea and cholera caused by unsafe water supply in conjunction with inadequate sanitation and hygiene (4).
In Africa, roughly 40% of the population does not have access to improved water supply and sanitation (5). The safety of drinking water is challenged due to contaminants from natural and man-made situations at global scale (6).The quality and safety of the drinking water continues to be an important public health issue. It is a pillar of primary prevention and control of pathogenic microorganisms such as bacteria, viruses, protozoa and helminthes (2). Therefore, a microbiological aspect is one of the specific standards to provide a basis for determining quality of drinking water (7) which is free from any microorganisms known to be pathogenic and free from bacteria indicative of pollution with excreta (8).
Availability of safe and wholesome drinking water for all is one of the most significant challenges faced by the municipal authorities worldwide. A clean and treated water supply to each house may be the norm in Europe and North America, but in developing countries, access to both clean water and sanitation are not the rule, and waterborne infections are common (9). Lack of safe drinking water is associated with high morbidity and mortality from excreta related diseases (10).
Therefore, this study fills the gap by conducting drinking water service sources of all sites and the consumers’ taps from all representative places of the city for the bacteriological and parasitological quality assessment and safety of municipal drinking water.
This study improves the scientific basis of drinking water, water quality and safety monitoring in Addis Ababa, an evidence for the AAWSA and the related stake holders to evaluate the quality and safety of public Municipal drinking water of the city, in regular basis. It helps to evaluate how drinking water of the city is safely treated, handled and free from burden of microbiological contaminants and can be base-line information for further studies concerning the Municipal drinking water of the city. It can also be helpful for Planning and policy development for water quality and safety and as a reference for drinking water Management and operational information.
Public health microbiological quality and safety assessment of drinking water sources in Addis Ababa City and identifying the dominating microorganisms.
The study was carried out at Addis Ababa Water and Sewerage Authority water quality and drainage Administration Microbiology laboratory from October 2015 June 2016. A total of two thousand nine hundred seventy six water samples; two thousand nine hundred fifty one water samples for bacteriological tests and twenty five water samples for parasitological tests were collected and tested from all service sources of public municipal drinking water. The fund was obtained from Addis Ababa University College of graduate studies and Addis Ababa water and sewerage authority.
In Addis Ababa city administration sub-cities and districts
A cross-sectional study design was conducted to assess the bacteriological quality and safety of public municipal drinking water samples from all the public municipal drinking water service sources in different localities of Addis Ababa city Administration, the parasitological quality and safety of Public Municipal drinking water samples were from twenty five service reservoirs receiving the produced water from the three main water plants.
The study had been conducting from October 2015 to June2016.
For water sample collection distilled water from the study laboratory was taken to all sample collection sites and carry along with the water sample back to the laboratory. Then both water samples were analyzed in parallel. Media, Reagents and Samples were run with Positive and Negative controls for the whole quality of the study under the whole supervision of Samplers, Environmentalist, water quality case team & biologists of AAWSA.
The frequencies and percentages were calculated to evaluate statistical significance of the bacterial and parasitological qualities and safety statuses of each service sources of the water. The data were analyzed by Statistical Package for Social Science (SPSS) statistical software Version 20.0 computer software program. The results were displayed/ shown in tabular and graphic forms.
Ethical clearance was obtained from the Ethical clearance and Research Review committee of Addis Ababa University College of Health Sciences.
All water samples were collected and tested with the unique identification code and all confidentiality of the results was maintained with great care.
All laboratory findings are available in hard copy by folder and the data analyses are available on Microsoft excel.
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
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.
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.
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.
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.
Consent for publication:
N/A
Availability of data and material:
The data for this study can be made available from the corresponding author when there is a reasonable need.
Competing interests:
The authors declare that they have no competing interests.
Funding:
This research work is funded by Addis Ababa University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
ACKNOWLEDGMENTS
My big gratitude to my advisors, all academic and management staff of AAU CHS department of Medical Laboratory Sciences, AAU College of graduate studies for funding.
I would like to express my acknowledgment to the AAWSA & all staff of water quality and drainage Administration Office for funding. all Addis Ababa residents of houses, cafes, hotels, restaurants, organizations, factories, schools, universities, offices & EPHI public health Microbiology.
AAWSA-Addis Ababa City Administration water and sewerage Authority
AAU-Addis Ababa University
UNICEF-United Nations Children’s Fund
USEPA-United States Environmental protection agency
WHO-World Health Organization