Fig. 4From: Mixture toxicity in the Erft River: assessment of ecological risks and toxicity driversSeasonal and spatial variation of risk quotients in the Erft River in 2016/2017. Variations along the river and during the years 2016/2017 are shown for the chronic mixture approaches. Red lines represent discharges of the first WWTPs, and the blue line the water discharges from lignite miningBack to article page