The Quality of Water From Artesian Drinking Fountains in the City of Zaječar - page 01

Area of Research

Zaječar is a city in the Zaječar district and the administrative center of the Timočka Krajina. According to the 2011 inventory there were 38,165 inhabitants. The City of Zaječar is located on the banks of two rivers, the Black and White Timok and on land whose shallower and deeper layers are rich with underground waters. Zaječar is a city with the largest number of artesian drinking fountains in Serbia. They provide a very distinctive mark for their environment and are part of the tradition of this city. Only 10% of groundwater of Serbia belongs to this type of aquifer whose reserves are slowly renewable and are not under the direct influence of surface water, and are therefore significantly protected from contamination (Velojić, 1999). During the first half of the 20th century, 65 public fountains were set up in the city (Petrović and Milojević, 1954). Drinking fountain artesian aquifers were drilled mainly between 1910 and 1990. At the beginning of the 21st century Zaječar had 40 functional artesian drinking fountains from which the population was supplied with drinking water.

Based on the most common occurrence of artesian water depth beneath the central part of the city, six water horizons were found. The first aquifer was at depths of 33 to 48 meters, the second from 98 to 118 meters, the third 150 to 180 meters, the fourth from 240 to 258 meters, the fifth from 300 to 324 meters and the sixth at depths of 398 to 407 meters below the surface. In the western peripheral area of the artesian aquifer in the area of the local community of "Kotlujevac", several artesian horizons were identified. The first horizon is at depths of 98 to 118 meters, the second at depths of 150 to 189 meters, the third at depths of 240 to 258 meters and the fourth artesian horizon at depths of 300 to 324 meters. Coverage of these aquifers is much higher than the city limits and ranges from 0.03 to 0.50 liters per second. In comparison with the aquifer of the inner city areas it can be concluded that "Kotlujevac" does not have a shallow aquifer from 33 - 48 meters, as well as four artesian water-bearing horizons which lie at the same depth and they are the same thickness. The thinnest aquifer is 9, and the thickest 30 meters (Petrović and Milojević, 1954). Despite the good solution for water supply from the central city water supply system, a large number of people are still using drinking water from artesian drinking fountains.

 

Materials and Methods

Samples of water were collected in April and October 2013, and May and October 2014 from 31 artesian fountains. The Regulation on the hygienic quality of drinking water (Official Gazette of the Republic Serbia, number 42/98 and 44/99), which is routinely used in the laboratories of the National Institute of Public Health "Timok" in Zaječar for testing water from artesian drinking fountains, from a bacteriological aspect prescribe testing of the following parameters: aerobic mesophilic bacteria, total coliforms, fecal coliforms, fecal streptococci, sulphite reducing clostridia, Proteus species and Pseudomonas auruginosa.

For an assessment of recent fecal pollution and the potential presence of pathogenic bacteria, total coliforms (cultivated on eosin-methylene blue agar at 37 °C for 24h), fecal coliforms (cultivated on MacConkey agar at 44 °C for 24h) and intestinal enterococci (cultivated on dextrose tellurite agar at 37 °C for 24h) were monitored. The presence of potential pathogen species was observed by cultivation on meat peptone agar (MPA). To accomplish the sanitary analyses, the presence of Proteus sp. (cultivated on phenylalanine agar at 37 °C for 24h), sulphite reducing clostridia (cultivated on sulphite agar at 37 °C for 48h) and P. aeruginosa (cultivated on pseudomonas agar at 42 °C for 24h) was also determined. The presence or absence of iron bacteria from the pellet obtained by membrane filtration was also monitored by direct identification under the microscope. According to the recommendation of the same regulation, testing of the physical and chemical characteristics of the samples were also carried out: turbidity, coloration, temperature, electrical conductivity, pH, KMnO4 consumption, as well as total content of ammonia, nitrites, nitrates, chlorides, iron (Fe) and manganese (Mn). The samples for laboratory analysis were taken under the Ordinance on the manner of taking samples and method for laboratory analysis of drinking water (Official Gazette of the Republic Serbia, number 33/87 and 13/91). Microbiological analyses according to standard methods (Drinking Water - Standard methods for hygienic validity, 1990) were carried out. All samples were processed in the laboratory within 6 hours of sampling.

 

Results and Discussion

The artesian drinking fountain in Zaječar represents alternative water supplies. The locations of the tested artesian drinking fountains were shown on the city map (Figure 1) and listed in Table 1. The majority of the artesian drinking fountains are located on the right side of the Black Timok, i.e. in the central part of the city. Fewer artesian aquifers are located on the left coast of the Black Timok (settlement Kotlujevac). During 2013 water sampling for chemical quality testing from artesian drinking fountains was performed twice, in April and October. Sampling in April covered 31 artesian fountains, while in October samples of water from 30 artesian drinking fountains were taken. The analysis for both periods showed hygienic contaminants in 17 water samples (Tables 2 and 3). Irregularity was reflected in the physicochemical characteristics due to the increased value of turbidity (expressed in Nephelometric Turbidity Units, NTU) in 6 samples. Higher values of turbidity from 5.56 to 7.18 NTU in April and in October from 5.32 to 8.66 NTU were detected. The analysis of pH values showed increased values in 11 samples that ranged from 8.6 to 9.0 in April (Table 2) and from 8.8 to 9.0 in October (Table 3). This slight increase in the pH value is characteristic of the deep waters of this area and does not adversely affect human health, as it indicates mildly alkaline waters. From the 6 samples that were irregular because of turbidity, 2 samples had noticeable color. The temperature of the water, in the test period, ranged from 11.9°C to 21.5°C in April and from 14.9°C to 21.7°C in October. All water samples in the examined period were bacteriologically correct, i.e., absence of coliform bacteria and coliform bacteria of fecal origin, streptococci, Pseudomonas aeruginosa, sulphite reducing clostridia and Proteus sp. was noted (data not shown).

 

Table 1: A list of artesian fountain localities in the city of Zaječar
Tab01

 

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Figure 1: The city map of Zaječar with localities of the artesian fountains.