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Transformation/dissolution characteristics of cobalt and welding fume nanoparticles in physiological and environmental media: surface interactions and trophic transfer

Time: Fri 2020-09-25 14.00

Location:, (English)

Subject area: Chemistry

Doctoral student: Nanxuan Mei , Yt- och korrosionsvetenskap

Opponent: Professor Iseult Lynch, School of Geography, Earth and Environmental Sciences, University of Birmingham

Supervisor: Universitetslektor Eva Blomberg, Yt- och korrosionsvetenskap, Kemi; Professor Inger Odnevall Wallinder, Yt- och korrosionsvetenskap, Materialvetenskap, Materialvetenskap; Doktor Jonas Hedberg, Yt- och korrosionsvetenskap, Fysik

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Nanoparticles (NPs) and nanomaterials (NMs) are present everywhere in the environment. They can form both as an act of nature and during human activities. Various kinds of NPs and NMs are engineered for different applications in the ongoing development of nanoscience and technology. Nowadays, concerns have emerged related to potential adverse effects of NPs on human health and the environment. Knowledge related to effects induced by more reactive metal NPs is scarce or even missing in some cases. Such information is crucial for risk assessments. The focus of this doctoral thesis has therefore mainly been placed on reactive metal NPs: stainless steel welding fume particles, cobalt (Co) NPs, and solution combustion synthesized (SCS) Co NPs, to investigate their transformation/dissolution characteristics in environmental and biological media.Environmental interaction studies were performed in terms of adsorption of biomolecules and natural organic matter (NOM) onto the surfaces of the NPs and their influence on dissolution, agglomeration, and size of the NPs in solution. Trophic transfer of Co NPs was investigated in an aquatic food web.The Co NPs rapidly agglomerated and sedimented in solution. Co ions were released from the NPs in both phosphate buffer solution and in freshwater, dissolution processes that were influenced by the adsorption of biomolecules and NOM. The trophic transfer of Co in the aquatic food web was shown to be affected by the extent of both agglomeration and sedimentation. No biomagnification was observed during the trophic transfer, and the addition of excreted biomolecules had no effect on the transfer.The dissolution of stainless steel welding fume particles was studied in PBS. The metal release data could help estimate the risk assessment of stainless steel welding fume particles.