Challenging Global Waste Management - Bioremediation to Detoxify Asbestos

Our plain-English summary of Challenging Global Waste Management - Bioremediation to Detoxify Asbestos, by S.L. Wallis, E.A. Emmett, R. Hardy, et al (Frontiers in Environmental Science, 2020).

The study

• Authors: S.L. Wallis, E.A. Emmett, R. Hardy, B.B. Casper, D.J. Blanchon, J.R. Testa, C.W. Menges, C. Gonneau, D.J. Jerolmack, A. Seiphoori, G. Steinhorn, T.A. Berry
• Journal: Frontiers in Environmental Science
• Published: 2020;8
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

As the 21st century uncovers ever-increasing volumes of asbestos and asbestos-contaminated waste, we need a new way to stop 'grandfather's problem' from becoming that of our future generations. The production of inexpensive, mechanically strong, heat resistant building materials containing asbestos has inevitably led to its use in many public and residential buildings globally. It is therefore not surprising that since the asbestos boom in the 1970s, some 30 years later, the true extent of this hidden danger was exposed. Yet, this severely toxic material continues to be produced and used in some countries, and in others the disposal options for historic uses - generally landfill - are at best unwieldy and at worst insecure. We illustrate the global scale of the asbestos problem via three case studies which describe various removal and/or end disposal issues. These case studies from both industrialised and island nations demonstrate the potential for the generation of massive amounts of asbestos contaminated soil. In each case, the final outcome of the project was influenced by factors such as cost and land availability, both increasing issues, worldwide. The reduction in the generation of asbestos containing materials will not absolve us from the necessity of handling and disposal of contaminated land. Waste treatment which relies on physico-chemical processes is expensive and does not contribute to a circular model economy ideal. Although asbestos is a mineral substance, there are naturally occurring biological-mediated processes capable of degradation (such as bioweathering). Therefore, low energy options, such as bioremediation, for the treatment for asbestos contaminated soils are worth exploring. We outline evidence pointing to the ability of microbe and plant communities to remove from asbestos the iron that contributes to its carcinogenicity. Finally, we describe the potential for a novel concept of creating ecosystems over asbestos landfills ('activated landfills') that utilize nature's chelating ability to degrade this toxic product effectively.

In plain English

This article is a review. It described three case studies of asbestos removal and disposal, summarized other researchers' work on whether living organisms can break down asbestos, and proposed a planned experiment. In Canberra, Australia, a programme to buy and demolish 1,022 homes insulated with loose 'Mr Fluffy' asbestos had an expected cost of about US$750 million. At two schools in Rarotonga, Cook Islands, asbestos-contaminated topsoil was buried on site, 3 m deep, with cost as the main determinant; removal and disposal was estimated at US$250,000. In Ambler, Pennsylvania, long home to a maker of chrysotile asbestos products, the Bo-Rit site was capped in place for US$27.1m, compared with US$269m for excavation and off-site disposal. At the Ambler Piles, waste still surfaced through erosion, fallen tree roots and animal burrowing. The authors cited laboratory studies reporting that fungi and lichens can remove iron from asbestos. Iron may contribute to asbestos's cancer-causing activity. The authors noted these studies used pure asbestos, not soil. The authors concluded that disposal of asbestos-contaminated soil remains unsolved. They proposed testing 'activated landfills', with initial trials planned for 5-year periods.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review with three descriptive case studies of asbestos removal and disposal, plus a proposed (not yet conducted) bioremediation experiment
• Who was studied: Asbestos removal and disposal projects in three countries: 'Mr Fluffy' insulated homes in Canberra, Australia; two of ten schools in Rarotonga, Cook Islands; and the Ambler Piles and Bo-Rit waste sites in Ambler, Pennsylvania, United States
• Exposure: Asbestos-containing waste and asbestos-contaminated soil. This included loose crushed asbestos insulation ('Mr Fluffy'), asbestos wall cladding and 'Super Six' roofing, and waste from manufacture of chrysotile asbestos-containing products in Ambler
• Main results:
  • Australia (Mr Fluffy): a programme begun in 2014 to buy and demolish 1,022 affected homes in the ACT had an expected cost of about US$750 million
  • Cook Islands: at both schools, contaminated topsoil was buried on site within school grounds, 3 m deep under 200 µm polythene, with cost as the main determinant. Removal and disposal at the two schools was estimated at US$250,000
  • Ambler, Bo-Rit site: cap-in-place remediation cost US$27.1m (estimated present-day value), compared with US$269m for excavation and off-site disposal
  • Ambler Piles: after remediation, visible waste products were still brought to the surface by erosion, roots of fallen trees or animal burrowing
  • From the authors' review of other researchers' studies: fungi and lichens have been shown to remove iron from solid asbestos materials
  • The authors proposed pilot-scale 'activated landfill' ecosystems over asbestos waste, with initial trials planned for 5-year periods
• The authors' conclusion: The authors concluded that long-term disposal of asbestos-contaminated soils remains an unsolved problem. They also concluded that bioremediation is worth testing as a way to at least partially remediate asbestos.
• Limitations the authors state:
  • The reviewed iron-removal studies used pure asbestos materials; how well these processes would work on asbestos fibres dispersed in soil is unclear
  • Bioweathering mechanisms are not fully understood and there is little data on degradation rates
  • Timescales for reducing carcinogenic potential are difficult to predict
  • The mobility of asbestos fibres in groundwater, especially after partial biodegradation, is not yet well known

Related studies

• A review of mechanochemistry applications in waste management — X. Guo, D. Xiang, et al. (2010)
• Construction and demolition waste management: China's lessons — H. Duan, J. Li (2016)
• Classification and management of asbestos-containing waste: European legislation and the Italian experience — F. Paglietti, S. Malinconico, et al. (2016)
• The Self-sustained High temperature Synthesis (SHS) technology as novel approach in the management of asbestos waste — L. Gaggero, M. Ferretti (2018)
• Efficient Management of Asbestos Waste Through Utilization as Mineral Additives in Portland Cement Production — K. Durczak, M. Pyzalski, et al. (2024)
• Microwave-assisted acid treatment for the mineral transformation of chrysotile as an alternative for asbestos waste management — S. Essih, L. Pardo, et al. (2024)

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