| Abstract [eng] |
The dissertation was prepared by Živilė Jurgelėnė at the Nature Research Centre during 2014–2018. The thesis addresses the toxicological potential of carboxylated CdSe/ZnS quantum dots and Cd single, quantum dots stability, their accumulation, penetration, distribution and explains the mechanisms of quantum dots impact to fish in early development stages. In this study, carboxylated quantum dots (4 nM) were not found to affect mortality of rainbow trout embryos, but they were found to cause mortality of larvae during both short- and long-term experiments. In contrast, mortality rates of embryos and larvae increased with increasing duration of exposure to Cd (2 µg/L). In many cases, alterations in biological parameters (respiration, growth, development and behaviour) of test-organisms were related to the duration of exposure to quantum dots and Cd. It was found, that tested quantum dots were chemically stable in the incubation water, because the metals did not release from quantum dots structure and did not cause metallothionein induction. However, quantum dots formed aggregates and agglomerates. For the first time was shown that quantum dots did not penetrate into the embryos but damage the chorion integrity. Meanwhile, quantum dots accumulated and distributed in larvae gills region. Results of fish toxicity experiments with metals and environmental organic and inorganic nano- and micro-scale materials and induction of metallothionein in tissues of fish larvae allow us to presume that the impact of chemically stable quantum dots on test-organisms is of mechanical nature. |
