22 research outputs found
Toxic effects multi-walled carbon nanotubes on bivalves: comparison between of functionalized and non-functionalized nanoparticles
Despite of the large array of available carbon nanotube (CNT) configurations that allow different industrial and scientific applications of these nanoparticles, their impacts on aquatic organisms, especially on invertebrate species, are still limited. To our knowledge, no information is available on how surface chemistry alteration (functionalization) of CNTs may impact the toxicity of these NPs to bivalve species after a chronic exposure. For this reason, the impacts induced by chronic exposure (28 days) to unfunctionalized MWCNTs (Nf-MWCNTs) in comparison with functionalized MWCNTs (f-MWCNTs), were evaluated in R. philippinarum, by measuring alterations induced in clams' oxidative status, neurotoxicity and metabolic capacity. The results obtained revealed that exposure to both MWCNT materials altered energy-related responses, with higher metabolic capacity and lower glycogen, protein and lipid concentrations in clams exposed to these CNTs. Moreover, R. philippinarum exposed to Nf-MWCNTs and f-MWCNTs showed oxidative stress expressed in higher lipid peroxidation and lower ratio between reduced and oxidized glutathione, despite the activation of defense mechanisms (superoxide-dismutase, glutathione peroxidase and glutathione S-transferases) in exposed clams. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to both MWCNTs.publishe
Effects of nanoparticles in species of aquaculture interest
Recently, it was observed that there is an increasing
application of nanoparticles (NPs) in aquaculture. Manufacturers
are trying to use nano-based tools to remove the barriers about
waterborne food, growth, reproduction, and culturing of species,
their health, and water treatment in order to increase aquaculture
production rates, being the safe-by-design approach still
unapplied. We reviewed the applications of NPs in aquaculture
evidencing that the way NPs are applied can be very different:
some are direclty added to feed, other to water media or in aquaculture
facilities. Traditional toxicity data cannot be easily used to
infer on aquaculturemainly considering short-term exposure scenarios,
underestimating the potential exposure of aquacultured
species. The main outputs are (i) biological models are not
recurrent, and in the case, testing protocols are frequently different;
(ii) most data derived from toxicity studies are not specifically
designed on aquaculture needs, thus contact time, exposure
concentrations, and other ancillary conditions do not meet the
required standard for aquaculture; (iii) short-term exposure periods
are investigated mainly on species of indirect aquaculture
interest, while shrimp and fish as final consumers in aquaculture
plants are underinvestigated (scarce or unknown data on trophic
chain transfer of NPs): little information is available about the
amount of NPs accumulated within marketed organisms; (iv)
how NPs present in the packaging of aquacultured products
can affect their quality remained substantially unexplored. NPs
in aquaculture are a challenging topic that must be developed in
the near future to assure human health and environmental safety
Effects of ZnO nanoparticles in the Caspian roach (Rutilus rutilus caspicus)
Most studies investigating the toxicity of zinc oxide nanoparticles (ZnO NPs) focused on the effect of size, whereas exposure concentration and duration remained poorly understood. In this study, the effect of acute and sub-acute exposures of ZnO NPs on Zn compartmentalization and biomarkers' expression were investigated in Rutilus rutilus caspicus (Caspian roach) considering various exposure scenarios: i) the assessment of the concentration-response curves and median lethal concentration (LC50); ii) the assessment of the effects of organisms exposed at LC50 value and one tenth of LC50 value of ZnO NPs suspensions for 4 d and 28 d, respectively; iii) the assessment of 14 d depuration period. The same concentrations of ZnSO4 were investigated. The highest Zn accumulation was detected in gill after sub-acute exposure (4.8 mg/L; 28 d) followed by liver, kidney and muscle. In gill, liver and muscle, Zn from Zn NPs accumulated higher concentrations. Depuration (14 d) decreased Zn content in each organ, but no complete removal occurred except for muscle. Biomarkers' activity was significantly over expressed after treatments, but depuration brought back their values to background levels and most effects were related to acute concentrations (48 mg/L; 4 d) and in presence of ZnSO4. Histopathological analyses showed that the exposure to ZnO NPs increased lesions in gill, liver and kidney, with a direct proportionality between alterations and Zn accumulated in the target organs. After depuration, lesions regressed for both ZnO NPs and ZnSO4, but not in a complete way. These data could contribute to increase the knowledge about ZnO NPs risk assessment in aquatic vertebrates, suggesting that the size of ZnO NPs can influence biomarker and histopathological effects