Soil pollution and your health

In Switzerland, soil pollution can be caused by human activity (industrial sites, landfills, transport infrastructure, shooting ranges) and is documented in the official Cadastre of Polluted Sites (KbS), maintained by the cantons and coordinated by the Federal Office for the Environment (FOEN). ^{[4] [5]}.

Soils can also contain naturally elevated concentrations of trace elements (geogenic background) depending on bedrock and soil formation. The Geochemical Soil Atlas of Switzerland helps to understand these regional background levels. ^{[1] [2] [3]}.

Potential exposure can happen through direct contact with soil and dust or via vegetables grown in contaminated soil. When planning gardening, playgrounds, excavation, or construction, it is worth checking both polluted sites and natural background values.

Natural occurrence of unhealthy elements in Swiss soils

The Geochemical Soil Atlas maps trace elements such as arsenic, cadmium, chromium, copper, lead, nickel and zinc in Swiss topsoils and shows where geological background concentrations are higher or lower. ^{[1] [2]}.

These map data, shown on GeoDa.ch housing reports, are designed for regional orientation and do not replace site-specific investigations (e.g. for building projects). The data should therefore be used with these limitations kept in mind ^{[3] [7]}.

Human-caused soil pollution and contaminated sites

Human activities can introduce pollutants such as heavy metals, mineral oils, solvents and combustion residues into the ground. Polluted sites are recorded in the Cadastre of Polluted Sites (KbS); a smaller share is classified as contaminated sites that need investigation or remediation. ^{[4] [5]}.

Many registered sites do not pose an immediate risk in everyday use, but the information matters for groundwater protection, construction work, and the safe use of gardens and play areas. For binding assessments and measures, the responsible cantonal authority is the primary contact.

Geoda helps users assess potential soil pollution at a specific address by combining authoritative maps, digitised data, and clear textual explanations in a single housing report. For a given location, Geoda identifies registered polluted sites from the Cadastre of Polluted Sites (KbS) in the surrounding area and indicates the type of activity involved, such as industrial use, landfills, shooting ranges, military sites, airports, or public transport infrastructure. Where available, the report also shows whether investigations or remediation measures are recorded for nearby sites.

In addition to human-caused pollution, Geoda provides information on the natural occurrence of potentially harmful elements in the soil. Based on the Geochemical Soil Atlas, the report highlights regional background levels of selected trace elements such as arsenic, cadmium, chromium, uranium, copper, nickel, zinc, and vanadium at the address. These data help place a location in its broader geological context.

By presenting both mapped layers and structured descriptions, Geoda enables homeowners, buyers, and renters to better understand environmental conditions around a property and to identify when further, site-specific investigations or contact with cantonal authorities may be appropriate.