Effects of various coin currencies on developing zebrafish embryo. (a) Different coin currencies described by country of origin, monetary value, mass, and composition. (b) Comparison of embryo (n = 10) morphology at 19 hpe after addition of coins; hpe: hours post exposure; control: embryos in egg water (no addition); SGD: Singapore dollar; ITL: Italian lira; CAD: Canadian dollar; USD: US dollar; KRW: South Korean won. Scale bar: 200 μm. (c) Quantification of early mortality at 19 hpe, according to group.

Assessment of effects by copper-plated coin. (a) Effects of US 1 cent coin on developing embryos (n = 10) at differential stages of development, indicating time point of exposure to penny: 1-cell (~0.25 hours post fertilization or hpf), sphere (~4 hpf), bud (~10 hpf), 10-somite (~14 hpf); control: embryos in egg water (no addition). (b) Magnification of representative image for relevant stages and time points. Scale bars: 200 μm. (c) Survival curve showing percent mortality at indicated stages and time points.

Effects of copper (II) ion solution on developing zebrafish embryos. (a) Higher concentration range of copper sulfate pentahydrate observed within 24 hours post exposure (hpe) at 1 and 19 hpe. (b) Lower concentration serial dilution of copper sulfate solution observed over a 48 h period at 24 h intervals. Control: embryos in egg water (no copper solution). Concentrations in header indicate the concentration of copper sulfate solution. Scale bars: 200 μm. (c) Aggregate of mortality data quantified from (a) and (b). Repeat labels are differentiated by letter of respective panel.