Abnormal development categories were widely variable within treatments.Nonetheless, a trend of increasing severity of abnormality with increasing metal concentration was observable (Figure 2.3). Observations with a total of less than ten abnormal individuals were removed from the dataset. The dominant abnormal category at a low concentration of copper was minor arm abnormality (skeletal), with stunted E. chloroticus becoming progressively dominant at intermediate concentrations, and the majority of larvae arrested in the gastrula stage at the highest concentration. A similar pattern was visible for zinc, but starting at intermediate-high concentrations with an increased frequency of stunted larvae, and a majority of severely abnormal larvae at the highest concentration. For lead, skeletal abnormalities were dominant at low and intermediate concentrations, with stunted arms and arrested development at the prism stage being the main abnormalities visible at the highest concentration. Furthermore, all three metals appeared to delay development of normal larvae, with the proportion of 4-armed pluteus amongst normal larvae decreasing with metal concentration.