Physicochemical and microbiological characteristics of the potable water supply sources in the area of Kozani,

In the present study, the physicochemical and microbiological characteristics of the potable water in the prefecture of Kozani are studied, according to the results of the analysis carried out in the Environmental Centre Laboratory, during 2002–2005. According to the Greek Legislation and the EU Directive for potable water, a water quality monitoring program was created for the County of Kozani, and the parameters of the Check and Audit Monitoring were examined for a number of samples from selected samples sites at regular intervals. Conclusions relative to the water adequacy of springs and drills, water tanks and supply network, as well as the possible reasons for water quality problems are presented in the study. Generally, the water quality depends on its chemical and microbiological condition. In the areas with penetrable formations and agricultural activity, the nitrates presence was observed in relatively stable concentrations in time. The water is easily infected during its transportation from the source to the internal water supply network and finally to the consumer. The condition of the water supply networks is a factor which contributes to the water quality.

(a) The water quality depends on its chemical and microbiological condition. The alteration of the chemical parameters of a water system used as potable water, especially when it is underground, depends on many parameters like the solubility of pollutants, their adsorption and halflife, from the climatic and hydrogeological conditions, mainly the percolation factor, the underground flow velocity of water, the slope and composition of the formations, the aquifer’s level [17,18]. At the study area the majority of the drinkable water analyzed samples come from deep drills passing from cohesive formations accordingly to geological maps and studies implemented in the area and therefore chemical composition relatively stable and generally not influenced from agricultural activities was observed. (b) In the areas with penetrable formations and agricultural activity, the nitrates presence was observed in relatively stable concentrations (Fig. 1) in time, because of their high mobility in soil [19]. About 5.7% of tested samples in the County of Kozani contained NO3-N at concentrations greater than 50 mg/L and lower than 210 mg/L. In Europe there are evidences that 87% of the agricultural areas have nitrate concentrations in groundwater above 25 mg/L and 22% above 50 mg/L [20]. In USA ground water accounts for 86% of their total water resources and provides 24 and 95% of the drinking water supply for urban and rural areas, respectively. About 6.4% of tested wells in the USA contained NO3-N at concentrations greater than 10 mg/L and 13.2% contained 3.1–10 mg/L. In Greece 70% of the total consumed water is used for irritating activities, 10% for drinking and 20% for industrial use.The nitrate problem of groundwater in Greece is not clear [21].