Multidisciplinary approach to the environmental quality assessment of Pietra del Pertusillo water reservoir

The Pietra del Pertusillo fresh-water reservoir is an artificial lake located in the high Agri Valley (Basilicata), in the southwestern part of Basilicata Region. It stores approximately 155 million m3 of water for both providing water supply for irrigation and drinking in Puglia and Basilicata Regions (southern Italian) and producing hydroelectric energy as well. Therefore, for its storage capacity and its watershed area, the Pertusillo dam is one of the strengths of regional water supply. Pertusillo lake lies within the National Park “Appennino Lucano Val d’Agri Lagonegrese” and it is part of Natura 2000, the ecological network of protected areas in the territory of the European Union, aimed to assure the long-term survival of Europe’s most endangered species and habitats.

This reservoir is also a natural laboratory for assessing the sediment pollution from human activities. In fact, in the last decades, in the high Agri Valley, a significant economic change took place, moving from a primitive economy to new industrial activities, among which the exploitation of the largest oil field in the onshore of western Europe. Other human activities developed across the marginal areas of the Pietra del Pertusillo lake, including: waste-water treatment plants, landfills, farms, plastics and other industrial activities.

This anthropogenic pressure may thus represent an impact factor on the environmental equilibrium (or status) of the Pietra del Pertusillo fresh-water reservoir and consequently the knowledge and control of the quality of its water and sediments represents a relevant environmental challenge.

Heavy metals are among the most common environmental pollutants stressing the biotic community and are released into the environment by the weathering of rocks or by many human activities. They are readily bioavailable and highly persistent; as metals do not undergo any metabolic change or degradation, they move up the trophic levels, undergoing processes of bioaccumulation and biomagnification critical for the health.

The surface layer of a sediment is in a continuous hydrochemical evolution, and this implies the possibility of heavy metals releases, from sediment into the aqueous matrix. The deep lacustrine sediments, instead, represent the historical memory of an ecosystem, recording the past environmental changes caused by both natural and artificial events;  the deep lacustrine sediments therefore allow us to reconstruct the history of the depositional events and define their possible origin.

However, there is a regulatory gap about dangerous substances in sediments of internal waters and even in Italy, the threshold concentration values (‘CSC’) for soils, laid down in the Single Environmental Text and subsequent amendments are used as standards for sediments quality.

Download here the PhD thesis!