The mechanisms of toxicity of engineered nanomaterials (ENMs) to the early life stages of freshwater fish, and the relative hazard compared to dissolved metals, is only partially understood. In the present study, zebrafish embryos were exposed to lethal concentrations of copper sulphate (CuSO) or copper oxide (CuO) ENMs (primary size ∼15 nm), and then the sub-lethal effects investigated at the LC concentrations over 96 h. The 96 h-LC (mean ± 95% CI) for CuSO was 303 ± 14 µg Cu L compared to 53 ± 9.9 mg L of the whole material for CuO ENMs; with the ENMs being orders of magnitude less toxic than the metal salt. The EC for hatching success was 76 ± 11 µg Cu L and 0.34 ± 0.78 mg L for CuSO and CuO ENMs respectively. Failure to hatch was associated with bubbles and foam-looking perivitelline fluid (CuSO), or particulate material smothering the chorion (CuO ENMs). In the sub-lethal exposures, about 42% of the total Cu as CuSO was internalised, as measured by Cu accumulation in the de-chorionated embryos, but for the ENMs exposures, nearly all (94%) of the total Cu was associated with chorion; indicating the chorion as an effective barrier to protect the embryo from the ENMs in the short term. Both forms of Cu exposure caused sodium (Na) and calcium (Ca), but not magnesium (Mg), depletion from the embryos; and CuSO caused some inhibition of the sodium pump (Na/K-ATPase) activity. Both forms of Cu exposure caused some loss of total glutathione (tGSH) in the embryos, but without induction of superoxide dismutase (SOD) activity. In conclusion, CuSO was much more toxic than CuO ENMs to early life stage zebrafish, but there are subtle differences in the exposure and toxic mechanisms for each substance.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.ecoenv.2023.114613 | DOI Listing |
Biomedicines
October 2024
Center for Environmental/Occupational Risk Analysis & Management, University of South Florida College of Public Health, Tampa, FL 33612, USA.
Sci Rep
October 2024
School of Clinical Medicine, Hebei University, Baoding, 071000, China.
Environ Sci Nano
September 2024
Instituto de Catálisis y Petroleoquímica, ICP-CSIC Marie Curie 2 28049-Madrid Spain
Methanol probe chemisorption quantifies the number of reactive sites at the surface of engineered nanomaterials, enabling normalization per reactive site in reactivity and toxicity tests, rather than per mass or physical surface area. Subsequent temperature-programmed surface reaction (TPSR) of chemisorbed methanol identifies the reactive nature of surface sites (acidic, basic, redox or combination thereof) and their reactivity. Complementary to the methanol assay, a dithiothreitol (DTT) probe oxidation reaction is used to evaluate the oxidation capacity.
View Article and Find Full Text PDFNano Lett
September 2024
Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin 10589, Germany.
Considering the increasing production of engineered nanomaterials (ENMs), new approach methodologies (NAMs) are essential for safe-by-design approaches and risk assessment. Our aim was to enhance screening strategies with a focus on reactivity-triggered toxicities. We applied tests to 10 selected benchmark ENMs in two cell models, lung epithelial A549 and differentiated THP-1 macrophage-like cells.
View Article and Find Full Text PDFSci Total Environ
October 2024
Department of Civil and Environmental Engineering, Northwestern University, USA. Electronic address:
Engineered nanomaterials (ENMs) can alter surface properties of cells and disturb cellular functions and gene expression through direct and indirect contact, exerting unintended impacts on human and ecological health. However, the effects of interactions among environmental factors, such as light, surrounding media, and ENM mixtures, on the mechanisms of ENM toxicity, especially at sublethal concentrations, are much less explored and understood. Therefore, we evaluated cell viability and outer membrane permeability of E.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!