Second Five-Year Review Report for Tacoma Tar Pits Operable Unit (Operable Unit 23) Commencement Bay Nearshore/Tideflats Superfund Site. EPA ID: WAD980723795, Tacoma, Pierce County, Washington

摘要

The results of this five-year review indicate that the remedy for the Tacoma Tar Pits site protects human health and the environment in the short-term. Groundwater contaminated with benzene continues to extend offsite, as identified in the previous five-year review. Currently, groundwater contamination does not present a threat to human health and the environment because shallow groundwater is not (1) used for any purpose in the vicinity of the site or (2) discharging into local surface water bodies (e.g., Puyallup River) where it could potentially impact ecological receptors. Operation and maintenance of the initial remedy components, plus continued operation and optimization of the groundwater extraction and treatment system for an undetermined period of time, will be required in order for the remedy to be protective in the long term.