A Content Review of Life Cycle Assessment of Nanomaterials: Current Practices, Challenges, and Future Prospects

Abstract

This paper provides a comprehensive review of 71 previous studies on the life cycle assessment (LCA) of nanomaterials (NMs) from 2001 to 2020 (19 years). Although various studies have been carried out to assess the efficiency and potential of wastes for nanotechnology, little attention has been paid to conducting a comprehensive analysis related to the environmental performance and hotspot of NMs, based on LCA methodology. Therefore, this paper highlights and discusses LCA methodology’s basis (goal and scope definition, system boundary, life cycle inventory, life cycle impact assessment, and interpretation) to insights into current practices, limitations, progress, and challenges of LCA application NMs. We found that there is still a lack of comprehensive LCA study on the environmental impacts of NMs until end-of-life stages, thereby potentially supporting misleading conclusions, in most of the previous studies reviewed. For a comprehensive evaluation of LCA of NMs, we recommend that future studies should: (1) report more detailed and transparent LCI data within NMs LCA studies; (2) consider the environmental impacts and potential risks of NMs within their whole life cycle; (3) adopt a transparent and prudent characterization model; and (4) include toxicity, uncertainty, and sensitivity assessments to analyze the exposure pathways of NMs further. Future recommendations towards improvement and harmonization of methodological for future research directions were discussed and provided. This study’s findings redound to future research in the field of LCA NMs specifically, considering that the release of NMs into the environment is yet to be explored due to limited understanding of the mechanisms and pathways involved.

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

“…Although many studies have been published in the last few years, there are still many limitations, as there were in the beginnings of LCA application [ 238 ]. This has been stated in recent reviews [ 240 , 242 ], and it was also debated in an LCA Discussion Forum a few years ago [ 256 ]. Some of those limitations are related to the system boundary considerations.…”

“…In the last two decades, a number of studies related to the LCA application in a wide range of nanotechnology fields, using different types of nanomaterials, have been conducted in a total of 128 works ( Figure 9 ). The reference studies are from 2001 to 2022 and were mostly recompiled from a few review studies [ 240 , 241 , 242 ] and from [ 222 , 243 , 244 , 245 , 246 , 247 , 248 , 249 , 250 , 251 , 252 , 253 , 254 , 255 ]. From this analysis, it is possible to observe a wide variety of nanomaterials and application fields.…”

“…However, a critical problem is that most of the existing LCA studies do not consider the end-of-life management scenarios (e.g., wastewater treatment plants (WWTPs), incineration, and landfill) that could act as sink compartments where the nanomaterials potentially accumulate [ 19 ]. Actually, to the best of our knowledge, there is no international regulation on the disposal management of nanomaterials [ 242 ]. This could be a concern accounting for the increased availability of nano-enabled products which will eventually enter into various waste treatment processes with no specific treatment being considered [ 257 ].…”

Environmental Properties and Applications of Biodegradable Starch-Based Nanocomposites

“…Thus it is difficult to compare the results between studies [ 138 ]. Furthermore, there are only very few mentions in the literature about the environmental performance of nanomaterials based on LCA methods which also has some limitations, including a lack of life cycle inventory data and characterization factors for NMs’ emissions [ 139 , 140 ]. Figure 10 depicts the simplified framework for the LCA of nanocomposite materials.…”

Enhancement of Anaerobic Digestion with Nanomaterials: A Mini Review

“…It is clear that a complete sustainability analysis (from environmental and economic perspectives) is necessary. Unfortunately, only very recently have some general reports regarding the sustainable design of engineered nanomaterials and the future prospects of the life cycle assessment of nanomaterials been published [61,62].…”