Publication Summary

This is the plan for the New Zealand mud snail potassium-chloride and magnesium-chloride bioassay study.

Each study conducted by the Washington State Department of Ecology (Ecology) must have an approved Quality Assurance (QA) Project Plan. The plan describes the objectives of the study and the procedures to be followed to achieve those objectives. After completion of the study, a final report describing the study results will be posted to the Internet.

The following QA Project Plan focuses on laboratory bioassay testing of the chemical compounds, potassium and magnesium chloride, on the aquatic invasive species New Zealand Mud Snail Potamopyrgus antipodarum (NZMS). NZMS specimens will be collected from the Long Beach area and brought to the laboratory, where they will be positively identified and exposed to varying concentrations of potassium and magnesium chloride for set durations. After a recovery period, the number of snails killed by each exposure will be determined, including a control group exposed to unaltered source water.

The bioassay will be performed in two stages: a preliminary screening followed by a final replicate test. Results from the screening will determine concentrations to be used in the replicate test. For potassium chloride, a single additive may be included to increase effectiveness: either a degreaser (Simple Green®) or a relaxant (low concentration magnesium chloride).

The replicate test will determine whether either potassium chloride or magnesium chloride offers a viable decontamination option for field equipment potentially contaminated by the NZMS. Recommendations will be made about optimal concentration, exposure time, and choice of additive (if any).