Publication details
Comparative investigation of toxicity; bioaccumulation and distribution of Cd-based Quantum dots and Cd salt in freshwater plant Lemna minor
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| Year of publication | 2017 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Quantum dots (QDs) are fluorescent semiconductor nanocrystals with increasing use, mainly as labels for tagging or imaging in biological systems1. Like other classes of nanomaterials, they may eventually find their way into the environment. Thus it is of a high importance to research the toxicity of Cd-based QDs to environmental organisms, which may come into contact with QD-containing products when they are discarded. The purpose of this study was to determine the toxicity of two different sources of cadmium, i. e. CdCl2 and Cd-based QDs, for freshwater model plant Lemna minor. Cadmium telluride QDs were capped with two coating ligands: glutathione (GSH) or 3- mercaptopropionic acid (MPA). Growth rate inhibition and final biomass inhibition of L. minor after 168-hour exposure were monitored as toxicity endpoints. Dose-response curves for Cd toxicity and EC50168h values were statistically evaluated for all sources of Cd to uncover possible differences among the toxicities of tested compounds. We also determined the total content of Cd and its bioaccumulation factors (BAFs) in L. minor after the exposure period to distinguish Cd bioaccumulation patterns with respect to different test compounds. Laser-Induced Breakdown Spectroscopy (LIBS) with lateral resolution of 200 um was employed in order to obtain two-dimensional maps of Cd spatial distribution in L. minor fronds. Our results show that GSH- and MPA-capped Cd-based QDs have similar toxicity for L. minor, but are significantly less toxic than CdCl2. However, both sources of Cd lead to similar patterns of Cd bioaccumulation and distribution in L. minor fronds. Our results are in line with previous reports that the main mediators of Cd toxicity and bioaccumulation in aquatic plants are Cd2+ ions dissolved from Cd-based QDs. |
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