Urban development is causing a continuous increase in sealed surfaces and the associated loss of natural and near-natural soils. The city's task in the area of soil protection is primarily carried out after the fact in the form of contaminated site management.

Contaminated sites have been systematically recorded and investigated in Bonn since 1985. In the initial phase, the focus was on old landfills, but since then contaminated sites (former industrial and commercial sites) have also been included. Areas suspected of being contaminated are summarized in a register of contaminated sites. You can obtain information about individual areas from the Lower Environmental Authority.