Tyson Wash

Registry placement date: Dec. 14, 1998

Score: 46

County: La Paz

Location: Town of Quartzsite, bounded by Sunset Street to the north, Oregon Avenue to the west, Main Street (Business I-10) to the south and Central Boulevard (SR-95) to the east with the known groundwater contamination existing northwest of the intersection of State Highway 95 and Business Route I-10 in Quartzsite 

Contaminants of concern: Tetrachloroethene (PCE) and trichloroethene (TCE) 

Action taken: As part of an early response action (ERA), a groundwater pump-and-treat system was constructed in 2003 to reduce contaminant concentrations in the aquifer and prevent migration of the plume to private drinking water wells. The remedial investigation (RI) and feasibility study (FS) have been completed, the proposed remedial action plan (PRAP) was completed in June 2008, and the record of decision (ROD) was completed in June 2009.

As of the February 2017 semi-annual groundwater sampling event, the pump and treat technology, in addition to in-situ chemical oxidation (ISCO), has effectively reduced tetrachloroethene (PCE) and trichloroethene (TCE) concentrations to well below their respective aquifer water quality standard (AWQS) at all monitoring points. The remedial objectives have been met, as verified by the analytical results from all private wells and ADEQ monitoring wells at the site, and no further remedial action is necessary. The remedy has achieved its goal, as concentrations of contaminants of concern (COCs) are below applicable AWQSs in groundwater at the site.

Status: On May 29, 2017, ADEQ removed this site from the WQARF registry, as regulatory cleanup levels have been achieved.

Community Advisory Board (CAB): None established