Although the sediment samples indicated toxicity to V. fischeri, no explicit adverse responses were observed in chronic C. riparius toxicity test. Adult emergence varied from50–100% (Table 3) but significant differences were not observed between exposures in the first experimental set up (Kruskal–Wallis test, p = 0.139) or the second experimental set up of the test (Kruskal–Wallis test, p = 0.239)