Fig. 2. Metal concentrations vs. depth in the three fields. Curves for the canopies are the average concentrations measured directly underneath the canopy and at the edge of the canopy dripline. Curves for the tilled field are an average from the two sampling pits. Average errors from replicate samples are ±1 mg kg^–1 As and ±2 mg kg^–1 Pb (error bars are smaller than symbols).