Fig. 5. Times series of measured (symbols) and predicted (continuous lines) concentrations for parathion (a, c) and its metabolite (b, d) in the layers 0 to 0.01 and 0.03 to 0.04 m during the 19 d of the experiment. For metabolite concentrations, the experimental points correspond to the total (paraoxon + p-nitrophenol) concentration.