Note sul degrado di ambienti carsici, con esempi dalla regione Puglia

Abstract

It Gli ambienti carsici presentano una elevata vulnerabilita all’inquinamento, e sono per questo motivo generalmente interessati da problemi di degrado. Le caratteristiche geologiche, morfologiche, ed idrogeologiche favoriscono fortemente il movimento di contaminanti verso le falde. Il presente contributo intende illustrare, per mezzo di tre significativi casi di studio, l’elevata vulnerabilita del territorio carsico della Regione Puglia. In due casi su tre, l’azione degli speleologi e stata fondamentale per la scoperta dei siti inquinati, la relativa denuncia alle autorita competenti, e l’impegno profuso ai fini della pulizia e della successiva salvaguardia della cavita. En Karst environments are highly vulnerable, and are affected by a variety of degradation and pollution problems. Local geology (fractured carbonate rocks), morphology (presence of a network of cavities produced by karst processes), and hydrogeology (rapid concentrated flow through fractures and conduits), strongly favour the movement of contaminants toward the water table. In particular, poor quality of subsurface water can derive from polluting substances flowing at the surface, and/or by direct input of liquid and solid waste in the water table through the systems of conduits and joints in the rock mass. As a consequence, water quality can be severely deteriorated, which implies very high economic and social costs in order to clean the polluted sites and restore the previous situation. High vulnerability of a typical karst region of the Mediterranean area is illustrated in this paper by describing three case studies from Apulia, southern Italy. Apulia region, where karst processes have played a prominent role in the development of the present landscape, is mostly underlain by intensely karstified limestones. Two cases of pollution due to solid waste into karst cavities (Grave di S. Leonardo in the Gargano Promontory, and Grave Pelosello in the Murge plateau), and degradation of Gravina Monsignore, a typical karst valley in south-eastern Murge, are described in the paper. In two out of three cases, degradation of the sites was discovered thanks to activity from local spelaeologists, which also acted as promoters for cleaning and safeguarding the polluted sites. These examples well highlight the mismanagement of karst territories (in particular, the common practice to dump refuse into sinkhole and caves), the pollution of limestone aquifers, and the effects that such pollution in karst areas might have in terms of risk to the public health.