Chemical and isotopic investigations on the deterioration of the Monumental Complex of S. Pietro in Corte in Salerno (Italy) caused by the rising waters

Two important streams are visible in the upper part of the city of Salerno (Italy), which are buried under the city, feeding the underground aquifer of the historic center. Until the beginning of the last century, this water was collected with wells present in churches and convents and fed mills, fountains, wash houses, thermae, and balnea. The most important testimony of the Roman period is the frigidarium discovered seven meters below the palatine chapel of Prince Arechi in 1970. In the underground area, frescoes from an early Christian church have also been brought to light. In the upper part of the underground area up to above street level, the formation of saltpetre efflorescence is observed. In this work, the plausible origin of these efflorescences was investigated through the isotopic determination of nitrogen. Moreover, through the chemical analysis of waters, which of the two main streams (the Rafastia and the Fusandola) fed the ancient frigidarium was identified.