The technical investigations reveal a mixed picture with regard to the type, severity and location of contamination in the subsoil. Excavation work will be supervised by specialists and documented on the basis of a detailed procedural and disposal concept. The documentation for each excavation stage is published on the AUE homepage.
The demolition work on construction site A will be carried out in line with a demolition and disposal concept agreed with the relevant authorities, the current laws, regulations and guidelines, and state-of-the-art technology. The Canton of Basel-Stadt has set strict limits for the construction companies, and monitors them on an ongoing basis.
The groundwater monitoring concept was approved by the Office for the Environment and Energy (AUE) together with the demolition application for stage 1. The project management checks the groundwater for pollution at defined points and at specific time intervals. The resulting readings are published on the AUE website.
The Air Hygiene Office of the Cantons of Basel-Stadt and Basel-Land (LHA) will monitor the air pollution during the civil engineering work and regularly publish the results on the BS Open Government Data Platform (OGD, probably from spring 2023). The most important parameters to be measured are fine dust, volatile organic substances (aniline, benzene, etc.), heavy metals and mercury.
From February 2021 to February 2022, the LHA carried out preliminary surveys (so-called baseline measurements) to determine the existing background exposure to volatile organic substances and mercury in and around the Rosental site. The report is available here.