Figure 2
Total and particulate lead (Pb) concentrations in the (A) main stem of the Athabasca River, (B) tributary streams and (C) groundwater. The bars in the graphs show the average Pb concentrations of triplicate samples and error bars are the standard deviations. The dashed lines in the graphs show the average dissolved Pb and dotted lines show the one standard deviation. The dissolved Pb in the main stem AR and tributaries were reported previously (Shotyk et al.45), but the dissolved Pb in groundwater is generated in this study. The results show that almost all the Pb is in particulate form. Note: while the concentrations of total and dissolved Pb in groundwater presented here represent accurate and precise measurements, the abundance of particulate matter in the groundwater samples is partly a reflection of the procedure employed (drive point wells) to collect them. The values presented here should not be viewed as the final word on the topic, rather the starting point: research on these groundwaters is ongoing.
