Several OECD guidelines for testing chemicals have been updated to include nanospecific considerations, which are generally effective. Despite these efforts, challenges remain in standardising the testing of nanomaterials in water, as particles tend to clump together, leading to unstable dispersions and irreproducible results.

Nanoforms of fertilisers or biostimulants sprayed directly onto plant leaves may contribute to more sustainable agricultural practices. However, it needs to be clarified whether the current legislation and methodologies sufficiently addresses the nanospecific properties of these products when assessing the benefits and risks for crops, the environment, and human health.

Two recent reports reviewed existing New Approach Methodologies (NAMs). One focussed on the purpose of regulatory risk assessment and the other on in silico methods for the Safe-and-Sustainable-by-Design (SSbD) of nanomaterials.

The European Scientific Committee on Consumer Safety (SCCS) evaluated information on genotoxicity of titanium dioxide used in cosmetic products. This was triggered by previous similar concerns for food additive E 171 (titanium dioxide, TiO2).

The past few decades of managing the uncertain risks for human and environment associated with nanomaterials have provided crucial insights for ensuring the safe and sustainable development of advanced materials.

The EU-funded HARMLESS project used the Early Awareness and Action System for Advanced Materials (Early4AdMa) to identify potential safety and sustainability issues of various inorganic aerogel mats. The approach required additional hazard data and exposure scenarios to be fully useful for ranking the different types of materials.

Two recent studies have proposed new methods to detect the presence of nanoparticles in food and cosmetics. The first study suggests a two-step approach to detect the banned food additive E 171. This involves screening for elemental titanium, followed by detecting nano-sized titanium dioxide. The second study used a quick screening tool to identify the presence of seven different nanoparticles in facial cosmetics. However, both methods have only been partially validated, and further improvements are required. There is a lack of reliable data on background titanium concentrations in food. A lack of reference matrices with known amounts of nanoparticles in consumer products is another challenge that needs to be addressed.

The use of Artificial Intelligence (AI) applications is quickly increasing and has the potential to revolutionize chemical risk assessment. For predicting the toxicity of nanomaterials, current models only work for relatively simple nanomaterials. There is a need to anticipate current developments and strategies to prepare for future AI implementation in chemical regulation.

Researchers from the EU Graphene Flagship have highlighted the complexity of assessing the safety of graphene and related materials. Such assessment requires detailed knowledge of safety-related physicochemical properties and the development of harmonised test methods. These lessons must receive ample attention in future innovation programmes on new materials.

By 2023, two European research projects related to the Malta Initiative were completed: Gov4Nano and NanoHarmony. These projects provided scientific support to thirteen OECD projects aimed at developing or modifying OECD Test Guidelines or Guidance Documents. However, more work is needed to finalise the OECD documents. The Malta Initiative has also identified further needs for harmonised test methods for future (advanced) materials and animal-free safety testing. The NanoHarmony White Paper guides on how to continue developing these test methods. However, it is uncertain how to identify and address future needs in the absence of resources for funding.