Nanotechnology is one of the key technological areas to boost Europe's competitiveness in the future. Nanomaterials have already been commercialized at various stages of the packaging supply chain from food storage to traceability and tracking.

Inmaculada Colmenar and Maidá Domat - ITENE

 

Their enhanced properties, such as UV protection, barrier to moisture, gases and volatile components, mechanical strength, or biodegradability, significantly improve packaging materials.

 

However, the increasing use of nanotechnology as an instrument for the development of new high value-added products contrasts with the scarcity of data relating to the safety of these materials for people and the environment. 

Since nanomaterials are considered substances, so far general legislation on protection for workers applies, in particular Framework Directive 89/391/EEC or Chemical Agents Directive 98/24/EC.

In this regard, the European Agency for Safety and Health at Work (EU-OSHA) concluded that REACH (Regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals) and CLP (Regulation on classification, labelling and packaging of chemicals and mixtures) provide the best possible framework for the risk management of nanomaterials when produced as substances or mixtures. However, within this framework more specific requirements have been necessary for nanomaterials, such as pulverulence, directly related to exposure.

 

The new regulation on nanomaterials

The European Chemicals Agency (ECHA) has indicated that the scope of REACH registration dossiers should be clear and provide explicit information on all forms of the substance, including nanoform. Recent compliance checks carried out by ECHA have highlighted the lack of nano-specific information in many registration dossiers, and registrants have been asked for additional data to ensure compliance.

The REACH Regulation gives the industry the responsibility to assess and manage the risks presented by chemicals and to provide adequate safety information to their users. However, this information is generally not easily extracted, since some characteristics of the substance in its nanoform differ from those of the substance in its micro or macrometric form, and there are no standardized protocols that allow to know some properties of the nanomaterials required by REACH.

On the other hand, safety data sheets (SDSs) are an important information tool for the prevention of risks presented by hazardous substances in the workplace. However, they currently contain, in general, little or no information on the presence of nanomaterials and their characteristics (MSDS evaluation and labels associated with the use of design nanomaterials).

In order for the SDS to provide for specific safety information to be considered for materials found in nanoforms, the European Commission published an amendment to Annex II on 20 June 2020, which will enter into force on 1 January 2021, and which lays down certain amendments that apply to nanomaterials: SDS belonging to one or more nanomaterials must indicate this using the term "nanoform"; it is necessary to detail the specific particle characteristics of the nanoform that may affect safety as described in Annex VI; in addition to solubility in water, the rate of dissolution in water or other biological or environmental means should be indicated; and finally, for substances to which the n-octanol/water coefficient does not apply, the stability of dispersion in different media should also be indicated.

However, there is a lack of consensus on the methodology and accessibility of standardized equipment to be used to measure exposure levels and to identify nanomaterials and emission sources.

 

Figure 1. Measurement of exposure during SiO2 nanoparticle production (ITENE)

 

Therefore, ITENE develops projects such as ReachingNano, supported by IVACE through the ERDF funds(IMDEEA/2019/83), focused  on developing tools to facilitate the quantitative assessment of levels of exposure to nanomaterials in the workplace by determining relevant parameters and properties such as the dust emission power of a selection of nanometric materials, micrometrics and granules, as well as the conceptualization of a new sensor to measure workers' exposure levels to these nanomaterials.

 

Determination of exposure levels

In terms of exposure levels, nanomaterials are generally detected by condensation particle counters (CPCs) or ultrafine particle counters (UPCs) and unipolar diffusion load-based devices. Despite advances in this area, today's devices face certain challenges when measuring in industrial environments: high cost, routine calibrations, frequent maintenance in dusty industrial environments, or operation and interpretation of results by highly skilled personnel.

 

Figure 2. Measurement equipment located during a campaign (ITENE)

 

Measure of the level of dustiness

The dustiness of a material determines the degree of ease of that material to release dust into the environment, that is, to dissogregate into the smaller particles that make up it. Dustiness evaluation is relevant in the context of the overall characterization of the material used to support compliance for bulk powders. According to REACH, which enters into force definitively in 2020, the presence of dust is quantified so that the risks of handling and exposure can be assessed, controlled and minimized.

The level of dustiness and the properties of the generated dust are not intrinsic properties determined by the material. Currently, it is not possible to predict the level of dustiness of a material from its physicochemical properties, but it is necessary to estimate it before introducing the material into the production chain, as dustiness is a critical aspect in determining the potential for respiratory and dermal exposure.

 

Figure 3. Dustiness test on a continuous drop device (ITENE)

 

Multiple studies have been developed to adapt the two protocols of the existing EN 15051:2007 pulse test (rotary drum, where dust is generated by rotating a cylinder with baffles, or continuous drop, consisting of a stream of dust falling on a surface), in which the applicability of the method has been tested in various metal oxides such as TiO₂ and SiO_2,as well as in carbon nanotubes (CNT), resulting in UNE-EN 17199 protocols.

The results show high variability, in addition to not being comparable to the pulse rates defined by applying the UNE EN 15051:2007 standard.

 

ITENE solutions: adaptation to the nano world

For this reason, some of the challenges that are intended to be overcome through the REACHingNANO project are:

 

· Include real-time measuring equipment to determine numerical and size concentration, as well as the specific area when there is the presence of nanoscale powder material.

· Related to the different methodologies and measurement protocols, a problem associated with the determination of pulverulence is the lack of harmonization in terms of measurement strategies: metrics, size ranges, equipment, sample preparation, results analysis procedure and inclusion of these in a report, which makes it difficult or impossible to compare pulverulence levels between different suppliers or materials.

· Since nanomaterials are often costly to produce and/or highly harmful, it is intended to work with sample quantities lower than conventional methods (300 to 600 g for the rotary drum).

· To develop smaller equipment for use directly in workplaces or measure the efficiency of risk control equipment (laboratory hoods, clean rooms, ventilated rooms, etc.)

· It is also intended to simplify and reduce the size of measuring equipment so that it can be used by the largest number of industries and include the information in the safety and registration sheets for specific chemicals.

 

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