European perspective on Environmental, health and safety aspects on cellulose nanofibrils

Cellulose nanofibrils (CNF) are promising biomaterials originating from renewable resources and benefiting from sustainable processing technologies. Due to their unique nano-specific properties, CNF have numerous potential applications, e.g. as replacement of fossil-based materials in packaging and in creating totally new functionalities for diagnostics. However, the same properties may potentially make them hazardous towards humans and the environment. As CNF consist of long, biopersistent fibres of high aspect ratio, inhaled NFC may have similar properties as nano- and microscale mineral fibres which have known occupational hazards. Due to the rapid technology and product development, the environmental health and safety risk assessment of CNF and related legislation is lacking behind, and knowledge on the toxicity of nanoscale celluloses is still scarce. Results published to-date suggest that even though no acute threats with the manufacturing and use of CNF have been revealed, there is evidence of dose-dependent toxicity, genotoxic effects and inflammatory effects. A key question in the risk assessment of CNF is whether the inflammatory and genotoxic effects observed were transient or could persist for a longer time, contributing to cancer risk. The existing evidence on the biopersistence and low clearance of CNF rise concerns on their toxic hazards which need to be further assessed by longer-term studies. It is recommended that testing is performed case-by-case, because e.g. chemical modification and raw material have been shown to influence the toxicity of CNF. Currently, the existing chemicals legislation and regulations based on the intended use of the material seldom consider nanomaterials separately from the corresponding bulk materials. However, there are several European, national and international initiatives for developing and implementing nanomaterial-specific regulations to ensure their safe manufacturing and use.