Fig. 3. The Pb_soil and plant Pb uptake (Pb_plant) in Brassica rapa (mustard) tissue analyzed by XRF. Mustards were grown in both the greenhouse (n = 4) and in situ in the test plots (n = 8). Each point represents an average of 2 to 4 Pb_soil measurements and 5 to 8 Pb_plant measurements.