An Emblematic Case of Pollution of Wells and Karst Springs Supplying the City of Ragusa (South-Eastern Sicily)

This paper deals with the occurrence of pollution in two important karst springs, supplying the aqueduct of the city of Ragusa, which happened in September 2010 and it is still taking place. Both springs show higher values of ammonia and the presence of salmonella, elements ascribable to wastewater of animal origin. According to this, investigations identified a number of farms present within the springs-protected areas as likely to have caused the pollution. These were imposed by ordinances to build adequate storage tanks for the animal wastewater. Paradoxically, the construction of these tanks led to a further worsening of the state of pollution, as the latter from episodic, linked to rainfall, became continuous due to the overflowing of wastewater from the tanks never emptied, as it was ascertained. A geological and geochemical study, preparatory to the execution of tracer tests, conducted by the Water Department of Genio Civile of Ragusa and ARPA (Regional Agency for the Environmental Protection), allowed a hydrogeological characterization of the recharge area and the definition of the hydrologic regime of the springs, that in this case, resulted as interconnected. Follow-up tests with fluorescent tracers, carried out on a few farms, were then interrupted because of the opposition of one of the owners. From that moment on, everything stops as for the research of the origin of the pollutant, while at the same time the situation gets worse, both in terms of environment, for the devastating effect on the ecosystem of the Ciaramite stream due to the spill in the riverbed of the polluted water springs, and for the resulting pollution of two municipal drinking water wells placed at the confluence of the Ciaramite stream with the Irminio river. The lack of further drinkable water determined the starting of the crisis of the city water distribution system having to turn to a supply of chance with tank trucks and shifts that created situations of considerable discomfort to major part of the citizens. At present, after 3 years from the start of the polluting event, despite the ordinances issued by the City Hall toward a number of livestock farms who do not comply with the collection of waste and its disposal, as a result we assist to the loss of a spring and the ecological degradation of the Ciaramite stream valley.