QUALITATIVE ANALYSIS AND STATISTICAL MODELS BETWEEN SPRING WATER QUALITY INDICATORS IN ALBA COUNTY, ROMANIA

Based on contemporary environmental issues, related to water scarcity, the research outlines the current situation regarding the quality of spring waters in Alba County. Spring water is an alternative that is less and less investigated and exploited if it is a free, natural, untreated source. The quality of spring drinking water is regulated by Law no. 458/2002 (transposing the Directive 98/83/EC on the quality of drinking water). Five areas with 132 water sources were monitored, and for the most representative and polluted springs, their monitoring (physico-chemical and microbiological indicators) was performed for a period of 3 years. Most sources are microbial contaminated regardless of the season or the water catchment and spring arrangement. There is also a diffuse microbiological pollution in some localities, which indicates that the phenomena of natural purification no longer occur. It was found that in Alba County the percentage of drinking spring water sources is relatively low as follows: Alba Iulia-Teius area - 37%, Sebe-Cugir-48%, Campeni-Zlatna - 72%, Blaj - 25%, Aiud-Ocna Mures - 20%. The correlative analysis shows that between the total viable count and other physico-chemical parameters (ammonium, nitrates and nitritesions) of spring water there are appreciable correlations. The correlation coefficients between these parameters vary between 0.67 and 0.92. The equations of the statistical models can approximate the variation in time of the microbial growth. These represent a control and prediction tool for the appreciation of the spring water quality in time, knowing only the physico-chemical parameters.