Body burdens for Cd or Se were determined for larvae at 120 hpf exposed to 20 μM Cd or Se equivalents of as-synthesized or weathered PEG5000-QDs, CdCl2, Na2SeO3, SeNPs, or SeNP + CdCl2. Values represent mean ± SE, n = 3 pools of 15-20 larvae each. In some cases, error bars were too small to be visible. Difference between as-synthesized and weathered QDs: *, p = 0.05; **, p < 0.001.