(A) Hydrodynamic size (mean ± standard deviation; nm) and potential zeta (mean ± standard deviation; mV) of ZnAl LDH dispersions (10 and 100 mg/L) in zebrafish FSW over time (0, 24 and 48 h).

Embryos and larvae of Danio rerio after exposure to the control (A, embryo (48 h)); B, larvae (72 h)) and to the concentration of 84.5 mg ZnAl LDH/L (C, embryo) and 1200 mg ZnAl LDH/L (D, chorion and embryo). The arrows in Figs. C and D show the adhesion of particles and/or aggregates/agglomerates of ZnAl LDH.

Fish activity, measured as distance (mm), after exposure to a range of concentrations of ZnAl LDH and control in two alternating light/dark cycles (A). Total swam distance (mean ± standard error; mm) by Danio rerio larvae (n = 3) after 120 h exposure to ZnAl LDH, during two alternating light/dark cycles (B). Asterisk (*) indicates a significant difference (p < 0.05) between treatments and negative control.

Total duration of locomotion (mean ± standard error) in seconds (s) during two alternating cycles of light/dark by Danio rerio larvae (n = 3) after 120 h exposure to Zn^---Al LDH. Asterisk (*) indicates a significant difference (p < 0.05) between treatments and negative control.

Biochemical endpoints measured in Danio rerio larvae (n = 3) after 120 h of exposure to 8.9–93.7 mg/L of Zn^---Al LDH (mean ± standard deviation): lipid peroxidation (LPO; A) and enzymatic activity of acetylcholinesterase (AChE; B); glutathione peroxidase (GPx; C); glutathione-S-transferases (GSTs; D); catalase (CAT; E); glutathione reductase (GR; F). CTL – negative control.

Comet assay results after 96 h exposure of ZnAl LDH (8.92–93.68 mg/L) in Danio rerio larvae (n = 5). Data are expressed as DNA content in the tail (A), the intensity of tail moment (B), comet height (C), comet length (D), and intensity of tail olive moment (E) (mean ± standard deviation). Values are expressed as a percentage (A), arbitrary units (B and E) and the number of pixels (C and D). Positive (CTL+; H₂O₂) and negative (CTL-; only fish system water) controls are indicated in light grey bars.

Metric multidimensional scaling analysis based on the Zn^---Al exposure data, namely (A) embryotoxicity and (B) behavioral and biochemical effects and genotoxicity. Symbols and numbers represent each LDH exposure concentration in mg/L. Vectors represent the most correlated variables (Pearson r > 0.8) with the most relevant axes of each ordination plot.