Superfund Research Program
Remediation of Asbestos Particles
- Project Summary
Plants and fungi, which grow in association with plant roots, release various organic chemicals (called exudates) to dissolve and acquire trace metal nutrients from soil minerals. The same exudates have potential to remove iron — a known cause of asbestos toxicity — and break down asbestos fibers to harmless silica and other minerals. The researchers have completed experiments demonstrating removal of iron from asbestos fibers in the presence of various exudates (Mohanty et al., J Hazard Mater, in preparation). Seeds, vegetative plant parts, and mycorrhizal fungi, which grow in association with plant roots, have been collected from soils naturally high in heavy metals and from heavy metal-polluted soils. The researchers used seeds to propagate plants in asbestos-contaminated soils and assessed the ability of the various fungal collections to promote plant growth in these soils. The vegetative plant parts and soils were analyzed for heavy metal content with the goal of determining whether and how much the metal content of plant tissues are influenced by soil metal content and the identity of the mycorrhizal fungi. The researchers have examined the release of iron from chrysotile using a specific type of exudate (called siderophore) that targets iron. Furthermore, the researchers have evaluated whether the presence of other organic acid exudates (not specific to iron acquisition) enhance or inhibit the siderophore-mediated removal of iron from asbestos mineral. Their results showed that the presence of a very small quantity of siderophore is sufficient to remove iron from asbestos that otherwise would not be removed.