Fig. 4
Mean and standard error of the mean of EC50 for baseline toxicity (a, b), dioxin-like activity (c, d) and estrogenic activity (e, f) in water samples from the river Horloff in March 2017 (a, c, e) and the river Nidda in May 2017 (b, d, f). White: reference sites, with H3R and N2R as statistical reference sites, light grey: restoration sites, dark grey: transect sites. Significant differences in baseline toxicity compared to the reference site H3R (shaded) were determined using one-way ANOVA and Bonferroni’s post hoc test. Significant differences in dioxin-like activity and estrogenic activity compared to the corresponding reference site H3R or N2R (shaded) were determined via Kruskal–Wallis test with Dunn’s post hoc test. If no bar is illustrated, the activity was below the LOQ or no activity at all was measured. *p < 0.05, **p < 0.01, ***p < 0.001, n = 3 with 8 pseudo-replicates each