Chemical and biological tests to assess the viability of amendments and Phalaris arundinacea for the remediation and restoration of historic mine tailings.
Recent research in the Upper River Derwent, NE England highlighted the contribution of historic mining and mineral processing areas as sources of particulate and dissolved potentially toxic elements (PTE) entering river sediments. Subsequent analysis of mining and mineral processing sites has confirmed the presence of significant Cd, Pb and Zn concentrations in loose spoil, tailings and unvegetated soils. The aim of this study is to evaluate the potential of several organic amendments and a perennial native grass species, reed canary grass (Phalaris arundinacea), to immobilize PTEs and stabilise contaminated soils. The plant specie was selected for its ability to rapidly colonize and establish on contaminated soils whilst not (usually) accumulating high levels of PTEs or thereby adding to dispersion. Preliminary pot trials using bulk samples of mine spoil and amendments are currently ongoing following an adapted British Standards (BS/EN 11269-2:2013) method for the effects of PTEs on above ground plant growth. A combination of biological and chemical approaches will be used to analyse the efficacy of the different amendments throughout this study. These include the use of the modified BCR sequential extraction procedure and single extractants to assess PTE bioavailability, the monitoring of changes in soil properties such as OM, pH and CEC and the measurement of above ground biomass after a 12-week growth period. Although several recent studies have conducted similar pot trials, very few have applied their results to actual field trials. The results of these experiments will used to implement a two-year phytoremediation trial at a former mine site beginning in Spring 2019