Publication Summary

During the summer of 1997, Ecology analyzed diquat in water samples from the Steilacoom Lake outlet (Chambers Creek) following treatment of Steilacoom Lake with the aquatic herbicide Reward. Eight of the fifteen samples collected were split with the herbicide applicator to conduct additional diquat analysis using an alternative laboratory method. Objectives were to determine if split samples analyzed for diquat by different methods yielded comparable results; obtain additional data on diquat persistence in the water column following Reward applications; and provide data on diquat concentrations discharged to Chambers Creek in order to refine the permissible Reward treatment regime in Steilacoom Lake.