Fig. 6

Observed and predicted mortality using the concentration addition (CA) model. Developing zebrafish were exposed to the metal mixtures from 1 to 120 h post fertilization (hpf) and mortality recorded. Results were compared to predicted mortality based on CA models when the Pb LC₂₅ (39.0 ppm, mg/L) concentration was held constant (A) or when the Pb LC₅₀ (73.76 ppm) concentration was held constant (B). Similarity of predicted and observed curves indicates additive interaction (within in shaded region) (A), where upper deviation from predicted curve suggests synergistic response (B). N = 3 biological replicates per treatment group with 50 subsamples per biological replicate.