Hyperaccumulation of lead using Agrostis tenuis

Abstract

In recent years the quest for a circular economy approach and the upcycling of secondary raw materials have been pushed in the global political agenda. Increased interest has been taken by the recovery of materials from sludges, brines, contaminated waters and other media, such as “mining” of waste. Contaminated soils have an interesting role in this process, and various methodologies have been developed using chemical, bacteriological and pyrometallurgical cleaning procedures. However, these procedures all involve the movement of high volume of materials and the disruption of the industrial landscape; furthermore, they often require the use of hazardous solvents and high energy processes. This work proposes to identify less impactful methods aimed at the recovery of metals from mining areas while preserving the landscape and avoiding environmental impacts such as the increase of CO2 for transport and increase hazard through use of solvents, this takes particular importance in areas of industrial heritage status. In particular, this work focuses on the use of Agrostis tenuis, an autochthonous species in mining areas of the UK, as a “mining tool” for the removal of lead. The selection of both the hyperaccumulator and the metal in this study are derived from the evaluation of the most common contamination in mining areas and the widespread prevalence of this hyperaccumulator and its resilience in highly contaminated abandoned mines. Aside from its presence within the mining areas, making it an autochthonous plant, Agrostis tenuis is selected for its visual morphology. Being a short grass, Agrostis does not change the visual appearance of the mining sites, most of which in the UK have a historic landscape status.