Only in a few instances have plastic items been acutely toxic to zebrafish embryos, and in these cases, toxicity was attributed to the release of residual acrylate monomer or surfactant. We hypothesized that the consumer-grade PCL was releasing some toxicant(s). To test this, we leached 4 pellets/mL of the consumer-grade PCL for 24 h at room temperature in zebrafish embryo medium and exposed embryos to the resulting leachate. The leachate was slightly more toxic than direct exposure to the pellets and displayed less variability (Figure ). We also exposed embryos to the pellets used to prepare the leachate ("pre-leached"). Mortality was delayed somewhat for embryos exposed to these pellets, i.e., pre-leaching the pellets appeared to reduce the toxicity of the consumer-grade PCL, at least initially.