The findings in this thesis improve the understanding of 1) the relationship between exposure characteristics and toxicity of ENPs, 2) the joint toxic action of ENP mixtures and the comparison to... Show moreThe findings in this thesis improve the understanding of 1) the relationship between exposure characteristics and toxicity of ENPs, 2) the joint toxic action of ENP mixtures and the comparison to metal salt mixtures, 3) how NOM affects the individual and joint toxicity of ENPs, 4) the extent of trophic transfer of ENPs along aquatic food chains, 5) the influence factors on trophic transfer, and 6) bioaccumulation, distribution and toxic effect on predators. This knowledge would provide a basis for data on individual and joint toxicity, bioaccumulation, and trophic transfer of ENPs for more realistic environmental risk assessment. Show less
The rapidly increasing commercial application of metallic nanoparticles within products will inevitably enhance the amount of NPs being released into soil. Assessment of the impact of metallic... Show moreThe rapidly increasing commercial application of metallic nanoparticles within products will inevitably enhance the amount of NPs being released into soil. Assessment of the impact of metallic nanoparticles (NPs) in soil ecosystems is a necessity for ensuring their safe and sustainable application. In this thesis, we integrated exposure routes and exposure dynamics of NPs to investigate the uptake, translocation and impacts of metallic NPs in plants upon long-term exposure. We furthermore investigated the long-term impacts of NPs on the rhizosphere soil bacterial community and the potential transfer and biomagnification within the lettuce - terrestrial snails food chain. Our results demonstrate that 1) root exposure induced more phytotoxicity than foliar exposure at equal exposure concentrations; 2) the phytotoxicity and accumulation of AgNPs in plants was shape- and size-dependent; 3) nanoparticulate Ag present in AgNPs suspensions that predominantly drive their impacts on green leafy plants; 4) the dissolution of AgNPs in soil is the dominant process influencing Ag uptake and translocation in lettuce; 5) long-term exposure to high concentrations of AgNPs altered the structure and composition of rhizosphere bacterial community; 6) NPs can be transferred from lettuce leaves to snails, as associated with increased potential risks to higher trophic level organisms. Show less
