A Multiparametric Approach to Cerium Oxide Nanoparticle Toxicity Assessment in Non-Biting Midges

The cerium oxide nanoparticles toxicity induced physiological, histological and biochemical alterations in freshwater mussels, Unio crassus

INTRODUCTION

Releasing of cerium oxide nanoparticles (nano-CeO2) to the nature has increased due to the widespread use in many fields ranging from cosmetics to the food industry. Therefore, nano-CeO2 has been included in the Organization for Economic Co-operation and Development's (OECD) priority list for engineering nanomaterials. In this study, the effects of nano-CeO2 on the freshwater mussels were investigated to reveal the impact on the freshwater systems on model organism.

METHODS

First, the chemical and structural properties of nano-CeO2 were characterized in details. Second, the freshwater mussels were exposed to environmentally relevant concentrations of nano-CeO2 as 10 mg, 25 mg and 50 mg/L during 48-h and 7-d. Third, after the exposure periods, hemolymph and tissue samples were taken to analyse the Total Hemocyte Counts (THCs) histology and oxidative stress parameters (total antioxidant status, glutathione, glutathione-S-transferase, and advanced oxidative protein products).

RESULTS

Significant decrease of the THCs was observed in the nano-CeO2 exposed mussels compared to the control group (P < 0.05). The histological results showed a positive association between nano-CeO2 exposure concentration in the water and level of tissue damage and histopathological alterations were detected in the gill and the digestive gland tissues. Oxidative stress parameters were slightly affected after exposure to nano-CeO2 (P > 0.05). In conclusion, this study showed that acute exposure of freshwater mussels to nano-CeO2 did not pose significant biological risk. However, it has been proven that mussels are able to accumulate nano-CeO2 significantly in their bodies.

CONCLUSION

This suggests that nano-CeO2 may be a potential risk to other organisms in the ecosystem through trophic transfer in the food-web based on their habitat and niche in the ecosystem.

Interactive effects of cyanobacterial metabolites aeruginosin-98B, anabaenopeptin-B and cylindrospermopsin on physiological parameters and novel in vivo fluorescent indicators in Chironomus aprilinus larvae

We aimed to determine the effects of single cyanobacterial metabolites aeruginosin-B (AER-B), anabaenopeptin-B (ANA-B), cylindrospermopsin (CYL), their binary and ternary mixtures on biomarkers of Chironomus aprilinus larvae: oxygen consumption, fat body structure and two novel fluorescent indicators: imaging of nuclei in cells of body integument, and the catecholamine level. The obtained results showed that oxygen consumption was inhibited by single tested cyanobacterial metabolites except for ANA-B at the lowest concentration (250 μg/L). Although the mixtures of the metabolites inhibited oxygen consumption with antagonistic interactions between the components stimulation was noted in the group exposed to the lowest concentrations of AER-B + CYL (125 μg/L + 125 μg/L, respectively) and the ternary mixture of AER-B + ANA-B + CYL (83.3 μg/L + 83.3 μg/L + 83.3 μg/L, respectively). In vivo fluorescent staining with Hoechst 34580 showed that single AER-B had lower cytotoxic potential on body integument cells than ANA-B and CYL and most binary mixtures except for AER-B + CYL induced synergistic toxicity. Catecholamine level was decreased in animals exposed to single metabolites, their binary and ternary mixtures; however, the interactions between the components in the ternary mixture were antagonistic. Fat body was found to be disrupted in the larvae exposed to single metabolites and their combinations. Antagonistic toxic interactions between the oligopeptide components were found in most binary and the ternary mixtures; however, synergistic effect was noted in the binary mixture of AER-B + CYL. The results suggest that in natural conditions Chironomus larvae and possibly other benthic invertebrates may be affected by cyanobacterial metabolites, however various components and in mixtures and their concentrations may determine varied physiological effects and diverse interactions.

Analysis of Nanomaterials on Biological and Environmental Systems and New Analytical Methods for Improved Detection

The advancing field of nanoscience has produced lower mass, smaller size, and expanded chemical composition nanoparticles over recent years. These new nanoparticles have challenged traditional analytical methods of qualification and quantification. Such advancements in nanoparticles and nanomaterials have captured the attention of toxicologists with concerns regarding the environment and human health impacts. Given that nanoparticles are only limited by size (1–100 nm), their chemical and physical characteristics can drastically change and thus alter their overall nanotoxicity in unpredictable ways. A significant limitation to the development of nanomaterials is that traditional regulatory and scientific methods used to assess the biological and environmental toxicity of chemicals do not generally apply to the assessment of nanomaterials. Significant research effort has been initiated, but much more is still needed to develop new and improved analytical measurement methods for detecting and quantitating nanomaterials in biological and environmental systems.