Management of Asbestos Containing Materials: A Detailed LCA Comparison of Different Scenarios Comprising First Time Asbestos Characterization Factor Proposal

Our plain-English summary of Management of Asbestos Containing Materials: A Detailed LCA Comparison of Different Scenarios Comprising First Time Asbestos Characterization Factor Proposal, by M. Pini, S. Scarpellini, R. Rosa, et al (Environmental Science & Technology, 2021).

The study

• Authors: M. Pini, S. Scarpellini, R. Rosa, P. Neri, A.F. Gualtieri, A.M. Ferrari
• Journal: Environmental Science & Technology
• Published: 2021;55(18):12672-12682
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

This work addresses the complex issue of asbestos containing materials (ACMs) management, by focusing on the scenario of six municipalities comprised in the Reggio Emilia province of Emilia Romagna Italian region. Particularly, the life cycle assessment (LCA) methodology was applied in order to assess in a quantitative and reliable manner the human toxicity as well as the ecotoxicity impacts associated with all of the different phases of ACMs management. The latter comprises mapping of ACMs, creation of a risk map for defining priority of intervention, encapsulation and removal of ACMs, as well as the as obtained asbestos containing waste (ACW) end of life. Particularly, a thermal inertisation treatment performed in a continuous industrial furnace was considered as the innovative end of life scenario to be compared with what actually was provided by the legislation of many countries worldwide, that is, the disposal of ACW in a controlled landfill for hazardous wastes. A characterization factor for asbestos fibers released both in outdoor air and in occupational setting was proposed for the first time and included in the USEtox 2.0 impact assessment method. This allowed us to reliably and quantitatively highlight that inertisation treatments should be the preferred solutions to be adopted by local and national authorities, especially if the obtained inert material finds application as secondary raw materials, thus contributing to a decrease in the environmental damage (limited to its toxicological contributions) to be associated with asbestos management.

In plain English

This was a life cycle assessment, a computer modeling study of environmental and health impacts. It was not a study of people's health. The authors compared two ways of handling asbestos-containing waste removed from building roof coverings in eight municipalities in Reggio Emilia province, Italy. Their unit of comparison was 150 tons collected over three months. The first way was heat treatment in an industrial furnace that turns the waste into an inert material. The second was burial in a hazardous-waste landfill. The authors proposed, for the first time, a factor for estimating potential cancer cases from asbestos fibers released into outdoor air and workplace air, built partly from data on carbon nanotubes. They estimated that encapsulation and removal work released 11.65 kg of asbestos fibers into air and 0.12 kg inhaled by workers. The landfill scenario scored higher on every toxicity measure, mainly because of modeled long-term metal leaks into groundwater rather than asbestos fibers. The authors concluded that, for toxicity burdens only, heat treatment was the more sustainable option. They noted that their results depended strongly on how impacts were allocated.

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: Life cycle assessment (modeling study) comparing the human toxicity and freshwater ecotoxicity impacts of two end-of-life scenarios for asbestos-containing waste (thermal inertisation versus hazardous-waste landfill), plus a no-removal scenario
• Who was studied: Management of asbestos-containing materials in the coverings of private and public buildings in eight municipalities of the Unione dei Comuni della Bassa Reggiana (Reggio Emilia province, Italy). The functional unit was the 150 tons of asbestos-containing waste collected and treated over three months.
• Exposure: Asbestos fibers (fiber type not specified) released into outdoor air and into indoor air, the latter used to represent the occupational setting. A new cancer characterization factor was built using some properties of multiwalled carbon nanotubes as stand-ins. Only inhalation was considered.
• Main results:
  • Proposed midpoint characterization factors for asbestos fibers (human toxicity, carcinogenic effects): 1.07 × 10^-2 cases per kg emitted for indoor air (occupational setting) and 1.63 × 10^-4 cases per kg emitted for outdoor air
  • In both scenarios, the encapsulation and removal phase was estimated to release 11.65 kg of asbestos fibers into air, with 0.12 kg inhaled by workers
  • In the landfill scenario, a further 3.98 g of asbestos fibers was estimated to be released into air during disposal at the landfill
  • Human toxicity, cancer impact for the 150 tons: 2.18 × 10^-1 cases for the landfill scenario, versus 3.33 × 10^-3 cases (mass-allocated) and 5.83 × 10^-3 cases (not allocated) for the thermal inertisation scenario
  • The landfill scenario produced higher damage than the thermal inertisation scenario in all USEtox impact categories (human toxicity cancer, human toxicity noncancer, freshwater ecotoxicity)
  • The main difference in cancer impact between the two scenarios came from modeled long-term groundwater emissions from the landfill, not from asbestos fibers. Chromium VI in groundwater contributed 98.5% of the landfill scenario's cancer impact.
  • In the thermal inertisation scenario, 32.6% of the cancer impact came from asbestos fibers released into air and 21.6% from fibers inhaled by workers, both during encapsulation and removal. The largest single share (39.9%) was chromium VI in water from a background filter-dust disposal process.
  • Total cancer impact attributed to released asbestos fibers (Table 3): 3.15 × 10^-3 cases in the landfill scenario, 1.80 × 10^-3 cases in the thermal inertisation scenario with mass allocation, and 3.157 × 10^-3 cases without allocation
  • A hypothesized 2030 scenario was modeled for Italy, assuming 58 million square meters (986 000 tons) of asbestos-containing materials at 10 wt% asbestos fibers. Leaving these materials unremoved gave a much higher number of potential cancer cases than either management scenario. The figures are shown only in Figure 3 and are not given in the text.
• The authors' conclusion: The authors concluded that, at least for these eight municipalities, thermal inertisation should be considered a more environmentally sustainable alternative to landfill disposal, limited to toxicity-related burdens. They also concluded that removal is necessary and urgent compared with no intervention.
• Limitations the authors state:
  • The asbestos characterization factor was built partly from data on multiwalled carbon nanotubes, and the authors described it as a first attempt
  • Results were significantly affected by the mass-based allocation criterion used for the inert by-product
  • Uncertainties from the unavoidable use of background database processes need careful evaluation
  • The higher impact of the landfill scenario depends mainly on the process used to model the landfill's long-term groundwater emissions
  • Only cancer from direct inhalation of asbestos fibers was considered. Ingestion was excluded.

Topics

Medical terms in this study, explained in our Lexicon: Encapsulation.

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