ABSTRACT
Paranhos constitutes one of the main water galleries excavated in the granite substratum of Porto City (Portugal) to gather the groundwater for public use during the past five centuries. This gallery is a Subterranean Cultural Heritage site with a potential use for underground geotourism under safe conditions. An environmental monitoring programme has been conducted in the site comprising rapid multi-parametric surveys and spatial-distributed measurements of tracer gases and microenvironmental parameters. This programme has allowed the identification of urban-induced causes of contamination of the aquifer and internal tunnel atmosphere (wastewater and gas leakage). This study has also comprised the determination of effective radioactive dose in different sectors of the tunnel for potential visitors based on 222Rn studies.
