Fig. 5. Phosphorus concentration in leachates of control and samples treated with water treatment residue (WTR) (fully incorporated with the soil mass [100%] and mixed with half of the soil mass [50%]). S₁ = 100% impacted A horizon; S₂ = 50% impacted A horizon, 50% E horizon; S₃ = 33% impacted A horizon, 66% E horizon.