Health and environmental safety aspects of nanofibrillated cellulose

Nanomaterials will improve the performance of many products in future but at the same time they exhibit novel properties and may expose humans and environment to new risks. One of the most abundant, sustainable and promising nanomaterial for forest sector is nanofibrillated cellulose (NFC). NFC is produced by grinding the cellulose fibres under high compression and shear forces. NFC forms an opaque and stable, well-dispersed, aqueous suspension consisting of long and curly fibrils with a high aspect ratio. Wood pulp and powdered celluloses are generally recognized as safe and can be used for example as a raw material for food contact materials or even as food additives. However, as with other nanomaterials, the biological effects of nanocelluloses cannot be predicted solely from the chemical nature of cellulose. The size, shape, aggregation properties, degree of branching and specific surface properties, among others, still poorly understood factors, may affect the interactions of cellulose nanofibers with cells and living organisms. In this study we evaluated the health, environmental and occupational safety aspects of nanofibrillated cellulose. Processing of NFC with either a friction grinder or a spray dryer did not cause significant exposure to particles during normal operation. Grinding generated small amount of particles, which were mostly removed by fume hood. Spray dryer leaked particles when duct valve was closed, but when correctly operated the exposure to particles was low or nonexistent. The toxicological tests with several human and mouse cell cultures did not indicate any cyto- or genotoxic properties. Studied NFC samples were not acutely ecotoxic in kinetic luminescent bacteria test (Vibrio fischeri) with studied concentration up to 0.5 % NCF.