I am a Lecturer in Physiology within the School of Health Professions and the School of Biomedical Sciences. My research interests are at the biology-chemistry interface of toxicology to understand how pollutants (notably micro/nanoplastics and nanomaterials, and related compounds) affect environmental and human health.  My research interests and experience covers three main areas:

1. The accumulation and effect of pollution on aquatic animals. My research has focused on dietary toxicology, specifically chemical exposure (engineered nanomaterials/micro/nanoplastics) on the fish gut epithelium. My work has implemented the 3R’s (replacement, reduction, and refinement) in chemical risk/hazard assessment, and developed gold-standard methods to measure particles in fish tissues through single particle ICP-MS. My research in nanoplastics has used world-leading radioisotope (¹⁴C) and meal-doping techniques to trace uptake into fish. 
2. The role of plastic pollution in human gut health and associated disease. My research in this area is focusing on the role of plastic pollution and the response of various human gut cell lines, including its ability to contribute to or exacerbate inflammatory bowel disease. This work us using in vitro approaches and involves method development for trying to quantify the plastic load at a cellular level. 
3. Assessing the trace element suitability of "alternative" diets (e.g., vegan) compared to "conventional" diets (e.g., meat). My work in this area is taking a "customers perspective" to making dietary changes that align with animal ethics and for sustainability, such as the reduction of meat consumption in favor of a pescatarian or vegan diet. Combing total element analysis (ICP-MS) with simulated in vitro digestion protocols, the concentration and behavior of like-for-like substitutions can be understood.

I am the module lead for the undergraduate Nutritional Biochemistry and Physiology and Genetics modules that is cotaught to Nutrition, Exercise and Health students and Dietetics students.

I supervise BSc (Biomedical Sciences, Dietetics), MDiet (Dietetics) and MSc (Human Nutrition) project students within their dissertation modules. 

1. PhD, Helisoa (Amadeus) Derjean (2024-2028). Determining the dietary accumulation and toxicity of nanoplastics and co-contaminants (zinc oxide nanomaterials) in fish. Director of studies (with Miguel Gomez-Gonzalez, Lee Hutt and Richard Thompson).
2. PhD, Samantha Harvey (2024-2027). Establishing the effect of microplastic and nanoplastic exposure on inflammatory bowel disease. Director of studies (with Lee Hutt and Raul Bescos).
3. PhD, Tom Walter (2023-2026): Helpful or harmful? Investigating the impact of blended fruit smoothies on metabolic risk factors for human health. Second supervisor (with Kathy Redfern and Gail Rees).
4. PhD, Namrata Pandey (2022-2025). Defining the biological importance of micro- and nano-plastics on liver and gastrointestinal health. Second supervosor (with Ashwin Dhanda and Lee Durndell).
5. Research Masters, Craig McHardy (2022-2024). Development of alternatives for in vivo fish bioaccumulation testing with nanomaterials. Second supervisor.

PhD thesis examiner

• Occurrence of microplastic in fish: presence, knowledge and solutions (2021, The University of Adelaide).
• Investigation on the ecotoxicological effects of polyethylene microspheres on Wami Tilapia (Oreochromis urolepis) (2024, University of Dar es Salaam).

Reviewer for Journals (2019-present), including:

• ACS Agriculture and Technology
• Aquaculture
• Discover Toxicology
• Ecotoxicology
• Ecotoxicology and Environmental Safety
• Environment International
• Environmental Science: Nano
• Environmental Sciences Europe
• Frontiers in Environmental Science
• Froniters in Physiology
• NanoImpact
• Nature Protocols
• Science of the total Environment
• Trace Elements in Medicine and Biology

Reviewed select grants for:

• Council on Ocean Affairs, Science & Technology - State Science Information Needs Program (2020).
• Natural Sciences and Engineering Research Council of Canada (2022).

• 2020-2023: NanoHarmony (https://nanoharmony.eu/, EU funded). This project has the mission to support the development of Test Guidelines and Guidance Documents for eight endpoints where nanomaterial-adapted test methods have been identified as a regulatory priority. I work on two aspects of nanomaterials: T1.2 bioaccumulation and T1.4 quantification in biological samples. T1.2 focused on developing alternatives to in vivo fish bioaccumulation testing, in line with the 3 R's (Replacement, Reduction, Refinement). T1.4 uses single particle ICP-MS to determine the particulate fraction in samples where we are trying to develop a reference material for nanomaterials.
• 2019-2022: MINIMISE (https://gtr.ukri.org/projects?ref=NE%2FS003967%2F1, NERC funded). Marine plastic debris has been recorded across all parts of the globe and its potential to cause harm to marine wildlife and the healthy functioning of the oceans is an area of huge current concern. Microscopic plastic debris, (microplastic <5 mm in size and with no lower size limit), is a particular concern since its small size allows it to be consumed by many marine organisms, including those at the base of marine food webs and/or intended for human consumption. My work focused on establishing the biological fate of nanoplastics in fish following dietary exposure. As nanoplastics are difficult to detect due to the carbon background of tissues, various tracer methods were used (palladium-doped nanoplastics and carbon-14).
• 2016-2019: NanoFase (http://www.nanofase.eu/, EU funded). Progress is needed in the prediction of environmental distribution, concentration and form (speciation) of nanomaterials, to allow early assessment of potential environmental and human exposure and risks, to facilitate safe product design and to include these aspects in nano regulation. The overarching aim of this project was to deliver an integrated exposure assessment framework for nanomaterials in the environment. The framework would incorporate the consequences of these transformations for transport and fate and among the different environmental compartments including organism uptake and local accumulation of ENMs in some environmental compartments. My work involved performing experiments to assess the dietary bioaccumulation potential of silver and silver sulphide nanomaterials in fish using ex vivo in in vivo methodologies. I also performed some of these aspects (the gut sac) in a rodent model to gain insights for human health assessments. During the project, I completed by Ph.D. and a research assistant post. 

Conferences organised:

• Local Organization Committee for the 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials (5-8th September 2023).

Other academic activities:

• Session on sample preparation for single particle ICP-MS as part of the workshop for the 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials (titled "The detection of nanoparticles in complex biological matrices"). 

Workshop presentations

• “Data progress on in vitro alternatives to fish” (November 2021). OECD/NanoHarmony Bioaccumulation Expert Group Workshop.
• "Meta-analysis of physico-chemical properties and in vitro alternative to fish" (February 2021). OECD/NanoHarmony Bioaccumulation Expert Group Workshop.
• "Determination of concentrations of ENMs in biological samples using spICP-MS – Measurement and Validation" (November 2020). NanoHarmony International Workshop: Gap Analysis and Data Requirements for TG and GD Development.

• Clark, N. J., Clough, R., Jones, M. A., Laycock, A., Smith, R. and Handy, R. D. (September 2023). Development of an in-house tissue reference material for nanomaterials: A case study of silver nanoparticles in fish. 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Clark, N. J. Khan, F. R., Mitrano, D. M., Boyle, D., Crowther, C. and Thompson R. C. (May 2022). Quantification of nanoplastics uptake into and across the fish intestine using palladium-doped nanopolystyrene particles. Society of Environmental Toxicology and Chemistry.
• Clark, N. J. (October 2021). The extraction and characterisation of nanomaterials in fish tissues using single particle ICP-MS. Symposium for the Canadian Society of Analytical Sciences and Spectroscopy. Panellist, invited speaker.
• Clark, N. J., Mitrano, D. M., Khan, F. R., Boyle, D. and Thompson, R. C. (November 2020). The dietary bioavailability of nanoplastics to salmon using an ex vivo gut sac technique. MICRO2020.
• Clark, N. J., Clough, R., Boyle, D., Eynon, B. P., Woznica, W. and Handy, R. D. (September 2019). The use of single particle ICP-MS to highlight species differences in gastrointestinal physiology: fish versus rodent. 14th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Clark N. J., Clough R., Boyle, D., Sharma, V. and Handy R. D. (May 2019). Detection of nano-sized particles in fish tissues following an in vivodietary exposure: a case study using silver nitrate, silver nanoparticles and silver sulphide nanoparticles. Society of Environmental Toxicology and Chemistry.
• Clark N. J., Boyle D. and Handy R. D. (May 2018). Development of a rapid screen to assess bioaccumulation potential: from ex vivo to in vivo using pristine and aged nanomaterials in fish. Society of Environmental Toxicology and Chemistry.

• Clark, N. J., Fischer, A. C., Durndell, L., Littlejohn, G. R., Plessis, A., Galloway, T. S. and Thompsons, R. C. (September 2023). Hot stuff: the use of radioisotope labelling to measure nanoplastic uptake into fish and plants. 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Jones, M. A., Clark, N. J., Clough, R. and Handy, R. D. (September 2023). An assessment of appropriate sample storage for biologically incorporated engineered nanomaterials. 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• McHardy, C. K., Clark, N. J., Clough, R. and Handy, R. D. (September 2023). Demonstrating the utility of the ex vivo gut sac technique with carbon-based nanomaterials as an alternative to in vivo bioaccumulation testing. 16th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Clark, N. J., Handy, R. D., Boyle, D., Vassallo, J., Green, C., Nasser, F., Botha, T. L., Wepener, V., van den Brink, N. and Svendsen, C. (May 2022). The bioaccumulation testing strategy for nanomaterials: correlations with particle properties and a meta-analysis of in vitro alternatives to in vivo fish tests. Society of Environmental Toxicology and Chemistry.
• Vassallo, J., Handy, R. D., Clark, N. J., Green, C., Nasser, F., Tatsi, K., Hutchinson, T. H., Boyle, D., Baccaro, M., van den Brink, N. and Svendsen, C. (May 2022).The bioaccumulation testing strategy for nanomaterials: physico-chemical triggers and read across from earthworms in a meta-analysis. Society of Environmental Toxicology and Chemistry.
• Clark, N. J., Woznica, W. and Handy, R. D. (September 2019). The dietary bioaccumulation potential of silver from silver nanoparticles, silver sulphide nanoparticles and silver nitrate in Wistar rats using an ex vivo gut sac technique. 14th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Handy, R. D., Clark, N. J., Vassallo, J., Silva, P., Silva, A. R., Grgić, M., Baccaro, M., Medvešček, N., Ferreira, A., van der Brink and Loureiro, S. (September 2019). Fate and bioaccumulation of silver from AgNO3 and Ag2S nanoparticles in a freshwater river mesocosm. International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Clark, N. J., Boyle, D. and Handy, R. D. (September 2017). An assessment of the Dietary Bioavailability of Pristine and Aged Silver Nanomaterials in Rainbow Trout Using an Ex VivoGut Sac Technique. 12th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Boyle, D., Clark, N. J. and Handy, R. D. (September 2017). Development of a tiered approach for the assessment of the dietary bioavailability of engineered copper oxide nanomaterials in rainbow trout. International Conference on the Environmental Effects of Nanoparticles and Nanomaterials.
• Clark N. J., Clough, R., Boyle, D. and Handy, R. D. (June 2017). Development of single particle ICP-MS to measure engineered nanomaterials in biological matrices. Current Trends in Nanotoxicology.
• Clark, N. J., Boyle, D. and Handy, R. D. (February 2017). Investigation of the Dietary Bioavailability of Silver Nanoparticles in Rainbow Trout Using an Ex VivoTechnique. Nanomaterial Safety Assessment.
• Shaw B. J., Letsinger, S. G. R., Correia, M., Ehrlich, N., Clark, N. J., Sharma, V. and Handy, R. D. (February 2017). The effects of surface coating on the toxicity of CuO engineered nanomaterials to early life-stage zebrafish (Danio rerio). Nanomaterial Safety Assessment.