The Microbiological Quality of Private and Communal Boreholes in the Tshitale-Hlanganani Region of the Limpopo Province, South Africa
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THE MICROBIOLOGICAL QUALITY OF PRIVATE AND COMMUNAL BOREHOLES IN THE TSHITALE-HLANGANANI REGION OF THE LIMPOPO PROVINCE, SOUTH AFRICA Potgieter N*, Mudau LS and Maluleke FRS *Dept of Microbiology, University of Venda for Science and Technology, Private Bag X5050, Thohoyandou, 0950, Limpopo Province, Republic of South Africa. [email protected] ABSTRACT A cross-sectional study was carried out to assess the microbiological quality of 97 private and 97 communal boreholes in the rural Thitale-Hlanganani area of the Limpopo Province, South Africa. Both bacterial and viral indicator microorganisms were used and included total coliform bacteria, faecal coliform bacteria, faecal streptococci bacteria, heterotrophic bacteria, Clostridium perfringens (vegetative cells and spores) and somatic bacteriophages. The South African criteria guidelines of good (negligible risk of microbial infection; fit for human consumption), marginal (slight risk of microbial infection; must be treated before consumption), and poor (risk of infectious disease transmission; not fit for human consumption) for water used for human consumption, with the relevant counts for each indicator organism, was used to group the private and communal boreholes according to the relevant indicator organism. Results indicated that although the majority of boreholes were placed into the good category, some boreholes did however fall into the marginal and poor categories for each indictor organism. This indicated the potential health risk present to the consumers using these boreholes for domestic water sources. Observations at the boreholes identified various potential sources of pollutions that could affect the microbiological quality of the borehole water. In conclusion, this study indicated the need for more intense monitoring of privately owned boreholes and the education of the rural communities on the installation and the maintenance of both private and communal boreholes. INTRODUCTION The World Health Organization (WHO) estimate that 1,5 billion people in the world do not have access to safe water and that an estimated 1,8 million people in developing countries, die every year from diseases associated with unsafe water and inadequate sanitation (1; 2; 3). South Africa (SA) is a developing country and was rated number 26 worldwide during 1997 in terms of water availability per person out of 149 countries (4). The backlog of water and sanitation in rural villages in SA is addressed through Reconstruction and Development (RDP) programs on water and sanitation, using intersectoral approaches within communities (5; 6; 7). The sole and most cost effective source of potable water supply in SA is groundwater (8). Ground water has the potential of serving communities in areas where water infra-structure does not exist and where water delivery is difficult due to arid conditions (9). It is estimated that almost two thirds of the rural population in South Africa depends on groundwater sources for domestic purposes (9). The majority of rural communities use groundwater without any treatment (10). In addition, the number of on-site sanitation systems in the villages makes the underground water aquifers vulnerable to contamination and the microbiological quality of borehole water is not always guaranteed to be microbiologically safe for human consumption (11). Consequently, the presence of viruses, bacteria, protozoa and helminthes can cause diarrhoeal diseases. In addition, the presence of certain chemicals such as iron, copper, zinc, cobalt, magnesium, selenium and chromium in ground water can also be detrimental to human health (10). Therefore, the quality of borehole water for domestic use needs to be monitored and the health risk associated with contaminated drinking water should be considered, hence the need for this study. MATERIALS AND METHODS Study site and water sampling procedures The study was carried out in the Tshitale–Hlanganani area, in the Vhembe District Municipality of the Limpopo Province of South Africa. This area is predominantly rural with a low social economic income (12). Groundwater is used as a major source of water supply (13). The majority of borehole pumps used in the area are either engine or electricity driven and a few pumps are operated manually. Only a few of the electric and engine driven pump the underground water directly to communal stand pipes. With the majority of the boreholes, the electric and engine driven pumps distributes the groundwater via storage tanks and reservoirs to the stand pipes (13). A simple random selection method was used to select 30 of 40 villages in the study area. In these 30 villages, a total of 97 communal boreholes and 97 privately owned boreholes were identified to be assessed in this study. Water samples were collected monthly from both private and communal boreholes between August 2002 and August 2003 to include dry and rainy seasons. Each borehole water sample (2 l) was taken using the standard collection technique as specified by SABS (14), and transported on ice to the laboratory. In locations where hand water pumps were used, the water samples were taken directly from the hand pump. In locations where the borehole was connected to a tap or distributed via storage tanks or reservoir, water samples were collected from the nearest tap from the borehole (14; 15). Detection of indicator organisms The membrane filtration technique (16) was used and all test were performed in duplicate. A volume of 100 ml of each water sample was passed through 0.45µm pore size, 47 mm diameter sterile filter membranes (Millipore, SA) and the membranes placed on the relevant substrate medium before incubation (16). The average number of colony forming units per 100 milliliter (cfu.100ml-1) was calculated and recorded. For the detection of total coliform bacteria in the water samples, m-Endo (DIFCO) agar plates were prepared in 90 mm Petri dishes according to the manufacturer’s specifications (Merck, SA). After placing the membranes the bacteria onto the agar media, the plates were incubated aerobically for 24 hours at 370C. All colonies with a golden metallic sheen were counted as total coliforms. For the detection of faecal coliform bacteria in the water samples, m-FC (DIFCO) agar plates were prepared in 90mm Petri dishes according to the manufacturer’s specifications (Merck, SA). After placing the membranes with bacteria onto the agar media, the plates were incubated aerobically for 24 hours at 44.50C. All dark blue colonies were counted as faecal coliforms. For the detection of faecal enterococci in the water samples, m-Enterococcus (DIFCO) agar plates were prepared in 90mm Petri dishes according to the manufacturer’s specifications (Merck, SA). After placing the membranes with the bacteria onto the agar media, the plates were incubated aerobically for 48 hours at 370C. All red-pink colonies were counted as faecal enterococci. Clostridium perfringens counts (vegetative cells and spores) were determined using specific perfringens selective OPSP medium (Oxoid, SA) with supplements. The OPSP agar plates were prepared in 90 mm Petri dishes according to the specifications of the manufacturer’s (Oxoid, SA). After placing the membranes with bacteria onto the agar plates, the plates were incubated in anaerobic conditions at 37˚C for 48 h using anaerogens sachets in order to produce anaerobic environment. Colonies appearing as dark brown to black were counted. Somatic phages were assayed according to the methods described by Grabow et al., (17) with Escherichia coli strain WG5 (18) as host. Presence-absence test was carried out according to the method described by Uys (19). Briefly: A volume of 500 ml of each water sample was poured into a sterile plastic 1l water collection bottle to which 5g Trypticase peptone, 4g Sodium Chloride and 5ml of a Calcium-Glucose solution were added. The presence-absence sample one milliliter of the specific host culture was added to each of the water sample and incubated at 37˚C for 24 h. The presence of somatic coliphages were determined by spot plating 5 µl of the presence-absence sample to a prepared phage plates containing a lawn of the WG5 host. The spot plates were incubated overnight at 37˚C and the bacteriophages allowed to produce zones of lysis or plaques where the suspensions have been spotted. Classification criteria for borehole water quality Both private and communal borehole water results were grouped into categories according to the total number of a specific indicator organism detected. The classification system described by DWAF (15) and SABS (16) was used to categorize each borehole: 1. good (negligible risk of microbial infection; fit for human consumption) 2. marginal (slight risk of microbial infection; must be treated before consumption) 3. poor (risk of infectious disease transmission; not fit for human consumption) Table 1 Categories used for water quality assessment (15; 16) Indicator Water quality assessment criteria Organism Good Marginal Poor Total coliform 10 cfu.100 ml-1 11-100 cfu.100 ml-1 > 100 cfu.100 ml-1 Faecal coliform 0 cfu.100 ml 1-10 cfu.100 ml-1 > 10 cfu.100 ml-1 Faecal enterococci 0 cfu.100 ml 1 cfu.100 ml-1 > 1 cfu.100 ml-1 Clostridium perfringens 0 cfu.100 ml 1 cfu.100 ml-1 > 1 cfu.100 ml-1 Somatic coliphages 0 cfu.10 ml-1 1 cfu.10 ml-1 > 1 cfu.10 ml-1 Cfu = colony forming units good = fit for human consumption poor = poses a health risk Statistical analysis Data was presented and entered into Microsoft Excel 2000. STATA version 7 Shapiro Facia was used to determine the normality assumption for continuous variables. For comparison of categorical data, Fisher exact test or chi-square test was used (if no expected cell values were less than five). The Mann-Whitney test (sample size, mean and standard deviation) was also used. RESULTS Total coliform The total coliforms results for water samples tested in private and communal boreholes during dry and rainy seasons were showed in Figure 1.