The influence of rainwater composition on the conservation state of cementitious building materials.

Rainwater is one of the main pollution tracers around the world. There are many reasons that can explain the presence of high concentrations of certain hazardous elements (HEs) in the rainwater (traffic, marine port activities, industry, etc.). In this work, rainwater samples were collected at six different locations in the Metropolitan Bilbao (Basque Country, north of Spain) during November 2014. HE concentrations were determined by means of inductively coupled plasma mass spectrometry (ICP-MS) and anions by ion chromatography. The pH and redox potential values on these samples were also assessed. According to the obtained results, different trends along the estuary of Bilbao have been observed. To corroborate some hypothesis, thermodynamic simulations and correlation analyses were also carried out using quantitative data. These trends are closely related to the surrounding pollution and marine influence. Finally, in order to ascertain the influence of the Metropolitan Bilbao rainwater on buildings materials, a recent construction was characterized. Using techniques such as Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM–EDS) and Raman Spectroscopy, different types of sulfates and nitrates were observed.