Comparison of spike-1 and spike-2 concentrations in water, sediments, and periphyton in the mesocosms in late summer of 2002 (Year 1) and 2003 (Year 2).
In the Year 2 panels, the number above each bar is the difference (%) between the concentration of spike-2 and spike-1 (i.e., [(spike-2) (spike-1)]/(spike-
1) 100). A difference was not calculated if concentrations of spike-1 and spike-2 were both below detection limits