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Size of agglomerates like a major contribution to silver nanoparticles aquatic toxicity
Autoři: Opršal Jakub | Pouzar Miloslav | Knotek Petr | Bláha Luděk | Plodíková Petra
Rok: 2015
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng Size of agglomerates like a major contribution to silver nanoparticles aquatic toxicity One of the general problems in aquatic toxicity testing of nanoparticles is their fast agglomeration and subsequent sedimentation, which limits the use of "standardized" protocols in the assessment of particle toxicity. The present work suggests an original approach enabling to control the maximal average size of nanoparticle agglomerates during the aquatic toxicity test. The modification is based on the variable frequency of exposure media exchange, i.e. frequent exchanges of the tested colloid depending on the nanoparticle concentration levels. The method was applied for the short-term toxicity test with the embryo and sac-fry stages of common carp (Cyprinus carpio). Toxicity of silver nanoparticles (AgNPs) with initial average hydrodynamic diameter (DH) of 40 nm was tested at four concentrations (5; 10; 25 and 50 mM). Based on the chemistry and behavior of AgNPs in the culture medium, two levels of maximal average sizes of agglomerates (200 and 400 nm) were selected, and exchanges of media were employed to control for formation of these types of agglomerates. The comparisons with the semi-static fish embryotoxicity test, where the formation of agglomerates had not been controlled, indicate that different sizes of agglomerates influence different stages of embryo development. Interestingly, larger agglomerates rather than original nanoparticle colloids were responsible for the most severe effects, which could be mechanistically explained by other observations during the study. Details on the novel testing approach and its advantages and limitations will be discussed.