## 4 Conclusions  
The reduction in the storage capacity of the reservoirs, related to the significant inflow of sediments, requires the initiation of dredging operations and the subsequent management of these materials, now labeled by legislation as waste [63]. To recover and reuse them for other uses, it is essential to perform characterization activities, which help define the specific properties of sediments and to identify the possible reuses. The present study analyzed the results of analyses on sediments sampled at the San Giuliano and Camastra reservoirs in southern Italy to verify their suitability for reuse.  
Tests showed that the downstream sediments of the reservoirs have a predominantly sandy grain size composition while upstream sediments have a mostly silt-clay composition. The absence of heavy metal pollution is observed, as the values obtained from the laboratory analyses, compared with the primary legislative references, are well below the regulatory limits, with a few exceptions. Some of the samples from the Camastra reservoir exceed the threshold values for Cobalt alone; on the contrary, for the San Giuliano reservoir, Arsenic exceeds the limits, again in a small number of sampling points. The assessment by determining the P\({}_{\rm i}\) and P\({}_{\rm N}\) pollution indices reinforces the aforementioned conclusion, allowing the sediments to be classified in the 'unpolluted' and 'low polluted' categories. The organic matter content was low in most of the samples analyzed; the highest content, over 2%, was found exclusively in sediments from the bottom of the Camastra reservoir. Similarly, laboratory tests showed the total absence of asbestos.  
Another conclusion reached is the absence of correlation between the sampling point and the heavy metal content of the sediments, except for the Be, Cr and Ni parameters in those of the San Giuliano reservoir. This is probably related to the different land use of the San Giuliano basin compared to that of the Camastra one, which is more anthropized by agricultural activities, also because, in both, the presence of urban areas, another factor influencing the heavy metal content, is of little relevance. Therefore, the potential cause of the correlation between land use and the content of Be, Cr and Ni in the sediments is hypothesized to be the extensive farming activity carried out in the San Giuliano watershed, and particularly the use of fertilizers composed of the previously mentioned metals, such as to govern their distribution in the sampled materials. On the other hand, no correlation was found between heavy metal content and organic carbon content. The same can be said about grain size composition. Therefore, organic carbon and grain size distribution cannot be counted among the main factors governing the distribution of heavy metals in sediments.  
Paper conceptualization, D.L.; methodology, D.L.; data providing, T.T.; software elaboration, A.M.N.M.; formal analysis, A.M.N.M.; writing-original draft preparation, A.M.N.M.; writing-review and editing, D.L. and A.F.P.; validation, G.R. and F.G.; supervision, A.F.P. and F.G.; project management and administration, A.F.P. and F.G. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data supporting this study's findings are available from the corresponding author upon request due to privacy.  
The authors would like to express their thanks and gratitude to the Ente per lo Sviluppo dell'Irrigazione e la Trasformazione Fondiaria in Puglia, Lucania e Irpinia (E.I.P.L.I) and to the Consorzio di Bonifica della Basilicata for their collaboration and technical support. Additionally, the authors wish to acknowledge [PERSON], PostDoc researcher at the laboratory \"Morphodynamic Continuentale et Cotiere -M2C\" of the University of Caen Normandie for providing help in the elaboration of the geological map.  
The authors declare no conflict of interests.