The Quality of Water From Artesian Drinking Fountains in the City of Zaječar - Page 03

Table 2: The physico-chemical analysis of water samples taken from artesian fountains in April 2013
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Table 3: The physico-chemical analysis of water samples taken from artesian fountains in October 2013
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During the 2014, water sampling for chemical quality testing from artesian drinking fountains was performed twice, in May and October. The sampling campaign in May included 30 artesian drinking fountains (one had no water), and in October water samples from 28 artesian drinking fountains (the three fountains had no water) were collected. The analysis of the samples showed for both periods hygienic contaminants in 16 drinking samples (Tables 4 and 5). Irregularity was reflected in the physicochemical characteristics due to increased values for turbidity and pH. Increased turbidity was detected in 5 samples taken in May (Table 4) and 3 samples taken in October (Table 5). Higher values of turbidity ranged from 5.04 to 7.33 NTU in May and from 5.17 to 5.91 NTU in October. From 8 water samples that were of unsatisfactory quality due to turbidity, 4 samples had noticeable color. In both sampling periods, a slightly noticeable yellow color of the water at the two drinking fountains was present. The analysis of pH values showed an increased pH value in water from 4 fountains in May (Table 4) and 5 samples in October (Table 5). The values ranged from 8.8 to 8.9 in May and from 8.8 to 9.0 in October. The temperature of the water in the test period ranged from 12.0°C to 20.3°C in May and from 14.5°C to 21.1°C in October. All water samples in the examined period were also bacteriologically correct (data not shown).

During the examination period an increased concentration of Fe (mg/L) in April 2013 was observed for 12 water samples, and in October for 11 water samples (Figure 2). In the analysis performed during 2014, increased concentrations of Fe were scored in May for 13 samples and for 8 water samples in October (Figure 2). Increased concentration of iron in drinking water poses no threat to human health. According to current scientific and expert guides on the health safety of drinking water (WHO, 2004 and 2011), increased iron concentration does not adversely affect human health, however it does change the organoleptic properties of drinking water (the color, smell, taste and the presence of visible residue), which consequently can cause justified complaints from consumers. Iron is a natural component of underground waters. Iron reaches the water mainly from the land through which the water flows (primary iron). Mostly, the iron encountered in waters originates from reni wells and deep artesian wells or pipes through which the water flows (secondary iron).

In the present quantity, the iron produces technical problems during distribution through the pipeline. Namely, in the pipes iron compounds turn into sludge, which creates a blockage, and when it appears on the tap, causes yellowish coloration of the water. Larger amounts of iron in the water could contribute to the growth of iron bacteria, which can cause a characteristic odor and metallic taste of water, noticeable coloration of water and the occurrence of turbidity, and if they accumulate in large quantities can lead to clogging of installations, pumps and taps (Dalmacija et al., 2007). The growth of iron bacteria is greatly influenced by dissolved iron in their environment. In only three samples of water (artesian fountains No. 11, 12 and 20) iron bacteria of the genus Siderocapsa were detected. All three artesian fountains are among the oldest in the city and they were built between the First and Second World War. At the drains of these fountains characteristic coloration of part of the drain was present, which indicates increased concentration of iron in the water (Figure 3). Bacteria of the genus Siderocapsa are very common in environments characterized by higher concentrations of Fe and Mn. In these areas there is a connection between the representatives of Siderocapsaceae and the presence of Fe and Mn. The cells of microorganisms than become a core metal deposition, which results in the formation of insoluble metal oxide that can fully overlay and coat the cell. Under the microscope the cells of Siderocapsa sp. were the color of rust due to the deposition of iron and sometimes of a dark-brown or olive-green color to black due to the presence of MnO2. These bacteria are not known to cause disease, but can cause undesirable stains, tastes and odors, affect the amount of water and create conditions where other undesirable organisms may grow. Also, for fountains in which the presence of iron bacteria was confirmed; the pH value was increased (7.6 - 7.8). Increased turbidity and a noticeable discoloration of water indicate the processes that occur at depths from where the water comes under pressure to the surface. Turbidity as a physical parameter should not adversely affect human health, but if it continues to establish higher levels with a tendency of growth, it is necessary to mark the tap that water is not recommended for drinking.

 

Table 4: The physico-chemical analysis of water samples taken from artesian fountains in May 2014
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Table 5: The physico-chemical analysis of water samples taken from artesian fountains in October 2014
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