Cellulose nanomaterials: life cycle risk assessment, and environmental health and safety roadmap

Cellulose nanomaterials (CNs) derived from wood fibers are renewable materials with wide applicability for use in consumer products as bio-based composite materials and have the potential to replace petroleum-based materials in many existing and novel applications. Because their nanoscale features may impart novel chemical properties and behaviors, it is necessary to address the environmental and safety aspects of CNs to ensure safety in commercial applications, before wide introduction into society. NANO LCRA, a proposed life cycle risk assessment framework, was used for pre-commercial screening of selected applications of CN as a method for systematically identifying and assessing potential risks of CN from occupational, consumer and environmental exposures throughout the product life cycle. The analysis identifies potential exposure scenarios, evaluates toxicity and assesses the adequacy of available data to characterize risk, highlighting data needs and gaps that must be filled to reduce current uncertainty about CN safety. The analysis revealed that occupational inhalation exposure associated with handling CN as a dry powder was the highest priority data gap including the challenge of quantitative measurement for exposure assessment, followed by gaps in knowledge about the toxicity of CN in consumer use products, such as packaging, particularly for food contact. The NANO LCRA findings were then organized into a roadmap for filling key data gaps to allow safety and sustainability assessment that prioritizes data needs according to risk significance to ensure that uncertainty about the CN safety does not interfere with the commercialization of products to market.