Lessons from long-term field phytostabilisation studies

Smelter waste deposits pose a threat to environment and human health worldwide. There is limited availability of long-term phytostabilization field studies evaluating and documenting persistence of tested remediation methods. The paper combines experience from greenhouse testing of most effective soil amendments and long-term field experiments aimed at optimizing phytostabilisation of toxic smelter waste deposits. We compared the impact of novel soil amendments and their combinations with traditional materials on metal solubility and the response of plants, soil organisms and microbial activity. A range of tested parameters included metal extractability and bioaccessibility, soil pH, electric conductivity and enzymatic activity. Soil pore waters were collected to determine trace element concentrations. A separate test was performed to study amendment effects on earthworm behaviour and metal accumulation. Field evaluations involved long-term smelter wasteland site reclaimed with biosolids and by-product limestone combined with implementation of resistant grass species. The data on metal extractability and bioavailability, plant cover, microbial activity, abundance and biodiversity is presented.