Synthesis and Characterization of New emerging Nanomaterials and tools for evaluating impacts on human health and Environmental Risks

The outcomes of the SCANNER project will directly contribute to the knowledge base needed for greater insights into the impacts of nanomaterials on environment and human health. The project will also contribute to future sound regulatory development for current and future emerging nanomaterials. Nanomaterials (NMs) are chemical substances or materials that are manufactured and used at a very small scale. The number of nano-based products increased by 30-fold between 2005 and 2015 and this number is set to increase in the upcoming years. Nanomaterials have unique properties with respect to their particle size, surface area and reactivity, charge and shape compared to their bulk or dissolved counterparts. The increasing use in industrial applications, numerous consumer products and water treatment etc. are likely to be a source of nanomaterials released into the environment. The SCANNER project aims to evaluate and improve existing approaches for hazard and risk assessment of nanomaterials identified as relevant to the Norwegian and Indian environment. Initially the project conducted a literature search on the environmental prevalence of emerging nanomaterials and identified suitable NMs for use in the project. The selected particles represent emerging particles with future applications that could see them entering the environment and having detrimental effects on human and environmental health. The particles identified were MoS2 (Molybdenum disulfide) and Mg-Al-LDH (Layered double hydroxide). The Indian partners successfully synthesized and supplied to both project partners. In 2022/2023 the project has focused on the testing of these particles with in vivo (both human health relevant and environmental) and in vitro testing and characterization. The initial tests showed low toxicity of both particles in acute exposures. Early results indicated that MoS2 appeared to be more toxic that the LDH, however, due the behavior in the exposure media there appear to be confounding factors that may have resulted in this effect. i.e. shading of algae and low food availability to the marine copepod Tisbe battagliai. In 2023 further in vitro and in vivo studies have been carried out on the two novel NMs. The first results of the in vitro assesments with zebra fish liver cells (ZFL) show no adverse effects of the LDH NM despite the high exposure concentrations used which presents their potential as an alternative material for environmental applications. In the case of the MoS2 nanosheets, a decrease in the metabolic activity and membrane integrity was observed albeit at high concentrations. The formation of Reactive Oxygen Species (ROS) appeared to be the most sensitive endpoint in the ZFL cell line. Ongoing work focuses on gene expression and NM uptake studies in vitro as well as comparing in vitro with in vivo responses using the zebrafish embryo test. In addition, a mussel study looking at the toxicity and uptake of both NMs was conducted. Mussels were exposed to both NMs at 0.1 and 1 mg/L for 14 days, followed by 7 days of depuration. A wide range of biomarkers were determined in mussels at different time points (0, 7, 14 and 21 days), as well as bioaccumulation in tissues. These included condition index, lysosomal membrane stability (LMS), micronuclei formation, DNA damage, acetylcholinesterase activity, antioxidant enzymes activity, lipid peroxidation, cellular energy allocation and metallothionein levels. MoS2 and Mg-Al-LDH NMs behaviour in exposure media was also evaluated using Transmission electron microscopy and Dynamic light scattering. Preliminary results seem to point to a significant effect in exposed mussels that is concentration and time dependent, with Mg-Al-LDH NMs presenting a clearer toxic response than MoS2 NMs, which is the opposite of what was observed in earlier studies. This is evidenced by the results obtained on the LMS, where a lower retention time was observed in mussels after 7 and 14 days of exposure to 1 mg/L Mg-Al-LDH NMs and after 14 days for 0.1 mg/L. For mussels exposed to MoS2 NMs, a significant decrease was only detected for 1 mg/L after 14 days of exposure. Lysosomal retention time returned to values similar to the control after the 7 days of depuration for all exposed mussels. Overall, this study provides valuable information on how new emerging NMs could become a potential risk for the aquatic environment and organisms. The project will continue to focus on studying the behaviour and impacts of these nanomaterials in the environment and on human health. Continued studies in vitro and in vivo are planned to understand the uptake, accumulation and effects of these particles. The project continues to employ a battery of model marine and freshwater species with different feeding habitats and roles in the aquatic food-web that will be used to identify the most sensitive and vulnerable.

There is a need to develop approaches for assessing hazard and risk of nanomaterials (NMs) to ensure adequate protection of environmental and human health. Despite recent progress and development in this field, there are still fundamental gaps in knowledge and approaches, hindering further realistic insight into the NMs impact. There is still insufficient mechanistic understanding of the relationship between intrinsic physicho-chemical and extrinsic properties of NMs that influence exposure and effect. In addition, there is differences in how observed adverse effects are reported and communicated, potentially leading to different interpretation of risks and impacts. SCANNER aims to evaluate and improve existing approaches for hazard and risk assessment of NMs by conducting controlled exposure experiments to obtain detailed knowledge on the mode of action (MoA) and effects of NMs under realistic environmental conditions. The project will be organised in 6 work packages (WPs) that each will contribute with improved knowledge and understanding of the potential impacts of NMs. Relevant particles from a Norwegian and Indian environmental and health perspective (WP1) will be identified and synthesized. State-of-the-art and novel methods for characterisation and quantification of NMs will be used and developed in WP2. A battery of effect-based tools from cell to organism level will be applied to assess MoA and to identify new biomarkers (WP3). The bioavailability, uptake and transport mechanisms of NMs will be studied in detail in WP4. The data generated in all WPs will be integrated in WP5 to develop a hazard and risk assessment approach that can be used for NMs. Finally, WP 6 will focus on dissemination and communication of data to the scientific community and relevant stakeholders in Norway and India. The knowledge obtained will aid future national and international regulatory assessment of NMs and will be disseminated to regulatory authorities such as OECD and ECHA.