Protection of carbonate aquifers against microbial pollution

Abstract

The carbonate aquifers provide the main drinking-water resources in Southern Italy. Several important towns, many smaller towns and countless villages utilize this water for their public water supply. Small springs are often utilized by bottling plants or thermal resorts. Nevertheless, groundwater is often contaminated by fecal bacteria because of the interaction between rocks having high permeability and microbial pollutants introduced in the environment by grazing and/or manure spreading. In order to protect these aquifers against pollution it is necessary to (a) correctly assess specific vulnerability to microbial contamination and (b) define protection zones which take into account hydrogeological peculiarities of carbonate aquifers. In both cases, an experimental approach has to confirm the effectiveness of solutions proposed. On the whole, the results of both field and laboratory experiments demonstrated the effectiveness of DAC method for specific vulnerability assessing in carbonate aquifers. In details, it was verified its effectiveness to show the diversified role of diffuse infiltration of precipitations through topsoil and fracture pattern and more or less concentrated infiltration of surface water in karst areas. The efficiency of specific protection measures has been experimentally verified in a test site.