This report evaluates the potential impacts of the West Point Treatment Plant flooding event in 2017 on Dungeness crab tissues. The assessment of contaminant concentrations in Dungeness crab tissues included two areas near West Point: Shilshole Bay marina and the northern part of Elliott Bay.  

Crab collected from the northern area of Elliott Bay did not suggest increases in contaminants related to the flooding event. The data analysis suggested four metals in crabs collected from Shilshole Bay area may have been influenced by the West Point flooding event. The increases in crab tissues were temporary. Data for other contaminants in crab collected from Shilshole Bay area were either not detected or did not suggest increases related to the flooding event. While the increase in crab tissue metal concentrations may have been influenced by West Point discharges, overall data variability and the limited historic data make it difficult to conclude this definitively. In addition, co-occurring factors such as heavier than normal rainfall between February and April 2017 likely increased stormwater pollutant inputs to areas of Puget Sound during this period, which may have contributed to variability in contaminant concentrations in crab tissues.