Fig. 3

Results of the bacterial bioluminescence inhibition test for the negative control (white diamond), the eluates (100 mg/L) of the three test materials (grey squares) and the positive controls (zinc sulfate and potassium dichromate; red and orange circles) after 5, 15 and 30 min of exposure, as individual values and means of n = 4 replicates (black dash). Effects were calculated in comparison to the mean value of luminescence in the negative control and positive effect values show luminescence stimulation, while negative values show luminescence inhibition. Asterisks denote significant differences between the treatments and the negative control (Dunn’s test: *: p < 0.05, **: p < 0.01)