A review on the bioweathering and bioremediation of asbestos containing waste materials in soils

Asbestos is a silicate mineral that occurs naturally and is made up of flexible fibres that are resistant to heat, fire, and chemicals and do not conduct electricity. Both anthropogenic disturbance and natural weathering of asbestos-containing waste materials (ACWMs) can result in the emission of asbestos fibre dust, which when breathed, can cause asbestosis, a chronic lung illness that happens due to prolonged exposure of such fibre dust, and can cause ‘mesothelioma’ cancer. Although asbestos mining and its utilisation had been banned in many countries, there is still a significant issue of ACWMs disposal in the built environment and abandoned sites. It is neither practical nor economical to safely eliminate ACWMs from the built environment, and it is estimated that globally, 4 billion metric tonnes of ACWMs require safe management strategies. The toxicity of inhaled asbestos fibre relies on its surface properties, and in particular the distribution of iron, which serves a critical role in pathogenicity by forming reactive free radicals that damage DNA, thereby trigging cancer. Examining the usefulness of higher plants and microbes in the bioremediation of soil contaminated with ACWMs is the prime aim of the review. Higher plants and microorganisms such as lichens, fungi, and bacteria often play a major role in the remediation of soil contaminated with ACWMs by facilitating the bioweathering of asbestos and the removal of iron to mitigate the toxicity of asbestos.