The organic compound 1,4-dioxane has been detected, at concentrations slightly higher than the Colorado groundwater standard, in groundwater monitoring wells up to 2.4 miles north of the Lowry Landfill Superfund Site.  EPA has evaluated the health risk associated with public exposure to 1,4-dioxane at these concentrations north of the site and found no significant health risk associated with surface water or groundwater. The extent of the groundwater plume has been determined through an extensive groundwater investigation conducted by the City and County of Denver and Waste Management of Colorado incooperation with EPA, CDPHE, and TCHD.

As a response meaure, Denver and Waste Management have implemented a groundwater extraction and treatment response action immediately north of the Lowry Landfill site to minimize the potential for additional contaminant mass to migrate northward beyond Section 31. Several groundwater extraction wells in the area of the plume are currently extracting contaminated groundwater which is being conveyed to the onsite wastewater treatment plant via a water pipeline. The wastewater treatment plant treats the groundwater along with other site groundwaters then discharges the effluent to sanitary sewer system for additional treatment at the Metro and Aurora municipal wastewater treatment plants. Additional extraction wells will be added as necessary. Denver and Waste Management continue to monitor groundwater in the area of the plume to ensure response action objectives continue to be meet and to monitor concentrations trends.

The documents included below show the most recent results of 1,4-dioxane testing that are available. The extent to which groundwater is being monitored along the Murphy Creek drainage is visible in these graphics. Additional groundwater monitoring to the north is in progress.

Fig. C-5.2

Fig. C-5.4

Fig. C-5.6

Fig. C-5.8

North End Op Areas