Tracing the Sources of Pollution of Wells and Karst springs Supplying Water to the City of Ragusa, South-Eastern Sicily

摘要

The present study deals with the pollution which has occured in two important karst springs, supplying the acqueduct of Ragusa city in Italy. Both springs show higher values of ammonia and the presence of pathogenic bacteria, elements ascribable to wastewater of animal origin. This investigations identif ied a number of farms present within the springs protected areas which likely have caused the pollution. At these farm was imposed by ordinances to build adequate storage tanks for the animal wastewater. Paradoxically, the construction of such tanks led toa furtherworsening of the state of pollution, as the latter from episodic, linked to rainfall, became continuous due to the overflowing of wastewaterfrom the tanks neveremptied, as itwasascertained. A geological and geochemical study, preparatory to the execution of tracer tests, allowed a hydrogeological characterization of the recharge area and the def inition 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 due to the non-cooperation from one of the farm owners. From that momenton, every research forthe origin of the pollutantgets stop and the situation gets worse, both in terms of environment and for the resulting pollution of two municipal drinking water wells placed at the confluence of the Ciaramite streamvalleywith the Irminio river. Afterpassing 3 years of the polluting event, despite the ordinances issued by the City Hall towards a number of livestock farms who did not comply with the collection of waste and its disposal, as a result the collectivity have assisted to the loss of a spring and theecologicaldegradationof the Ciaramitestreamvalley.