Fig. 4From: Assessment of pesticides in surface water samples from Swedish agricultural areas by integrated bioanalysis and chemical analysisAryl hydrocarbon receptor activity measured in human hepatoma HepG2 cells, transiently transfected with an aryl hydrocarbon receptor sensitive luciferase reporter. Cells were exposed to concentrated water samples for 24 h prior to the measurement of luciferase activity (mean, n = 4). Bioactivity was normalized to vehicle control, set to 1. Solid line indicates the cut-off value of ≥ 2-fold induction. For standard deviation, refer to Additional file 4: Table S4Back to article page