Bioaccessibility testing for metals at mine sites

Abstract

Knowledge of bioaccessible metals in soils is relevant to the rehabilitation of mine sites and remediation of mined land. Soils of metal mine sites are commonly enriched in metals and metalloids due to mine waste dumping, atmospheric fallout from smelter emissions as well as dust deposition and erosion of particles originating from ore stockpiles, tailings storage facilities, waste rock dumps and exposed mine workings. Upon mine closure, the establishment of an effective and sustainable vegetation community represents an integral part of mine site rehabilitation. Only a vegetated and uncontaminated landscape will lead to site stability, effectiveness of dry covers, minimization of deleterious offsite effects and return of the mined land to a condition that allows a particular post-mining land use. Moreover, plants may represent pathways of metals and metalloids from contaminated substrates into local foodchains. Consequently, a solid understanding of the current and future bioaccessibility of metals and metalloids is of key relevance for assessing mined land for rehabilitation purposes. This paper presents a review of the literature concerning tests that are used to assess and predict the bioaccessibility of metals in contaminated and mining environments.