Figure 4. Concentrations of selected metals in suspended sediments discharging from springs (yellow background) and in surface streams (blue background) are compared. Only for lead and zinc, two metals with a strong urban source signal (Callender and Rice, 2000), were the median concentrations higher in surface-water sediments than in spring sediments. Relative magnitude of concentrations was compared to sediment-quality guidelines (MacDonald and others, 2000), as indicated by symbol color.
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