Fig. 4. Box chart of the pooled methemoglobin (metHb) values from (A) control zebrafish, (B) zebrafish exposed to 0.6 mmol l^–1 nitrite for 1, 2 and 5 days, and (C) zebrafish exposed to 2 mmol l^–1 nitrite for 1 and 2 days. The boxes are determined by the 25th and 75th percentiles, whiskers show the 5th and 95th percentiles, and crosses the 1st and 99th percentiles. The median is given by the horizontal line in the diamond boxes, and the mean for each pooled group is given by open squares. The filled symbols to the left of the boxes show the individual binned data points in each of the three groups.