Department Surface Waters - Research and Management

Excavated rock from underground construction is Switzerland’s largest waste stream. This material must be reused where possible for landscaping, recultivation or lake restoration. However, geogenic contamination of rocks with trace elements such as arsenic, chromium or nickel can complicate their safe reuse and pose risks to water resource quality. This project assesses trace element leaching from extracted rocks through field and laboratory studies. The goals are to:

1. determine factors and mechanisms controlling trace element release, including grain size, minerology, and biogeochemical conditions in the reuse environment
2. eventual fate of trace elements in deposited material and deposition environment
3. options to mitigate risks associated with rock reuse.

The reuse of extracted material with geogenically elevated trace element contents will remain an important issue in densely populated regions like Switzerland, and a robust database is key to facilitating stakeholder decision making and ensuring safe reuse.