Assessement of Interaction between pH and Different forms of Carbon Dioxide from Naturally Underground Aquatic Ecosystems

Abstract In this work were evaluated the correlations between different forms of carbon dioxide naturally existing in fountain waters and the pH. Water samples were taken from five wells equally placed on the surface of Picior de Munte area in Dambovita county and were collected in each of the four seasons (spring, summer, autumn and winter). They were evaluated two forms of carbon dioxide (one was the aggressive CO2 and the other was that sequestered in bicarbonates molecules). It was used titration method based on the principle of conversion calcium carbonate in to bicarbonate form. The results showed that both forms of carbon dioxide naturally founding in underground water are related to the pH, and also are varying from a season to the other. For example, both forms of carbon dioxide significantly were influenced by pH in summer and in spring also, the proof being the values of regression index wich was 0.583 and respectively 0.679. That is showing a moderate to strong influence depending on the season. In autumn and winter, the influence of pH on carbon forms analyzed was lowest one, the regression index value being 0.309 and 0.260. Also, the influence of carbon dioxide forms on the water pH level varied also from a season to another. Thus, carbon dioxide from bicarbonates strongly influenced the water pH in spring and autumn seasons, so the regression index value was 0.783 and respectively 0.548. But in winter and summer the influence ranged from moderate to weak (R2 = 0.413 and 0.316). The aggressive carbon dioxide significantly influenced water pH in the summer season, the fact is proved by the value of regression index which was high, 0.857. In the others seasons the influence of aggressive carbon dioxide was insignificant.