Waste Management strives to ensure groundwater protection by analyzing samples from 10 permanent groundwater monitoring wells on the active portion of the landfill. Over the past two years, up to 17 additional wells have been tested for groundwater quality around the perimeter of the landfill.

Groundwater wells are installed in order to monitor groundwater conditions. Waste Management monitors for 60 organic and inorganic compounds and metals. Groundwater monitoring wells are sampled and inspected on a regular basis and analyzed by an independent laboratory. The reports are submitted to the ADEQ for review.

Since Waste Management acquired the Tontitown Landfill, there have been limited groundwater detections of very low levels of cadmium and vinyl chloride. As a result, Waste Management implemented a "Nature and Extent Study" to determine what was causing the presence of cadmium and vinyl chloride in some of the wells. The study, completed in late 2003, determined that the cadmium was naturally occurring and that the vinyl chloride was derived from the presence of landfill gas. However, the study found both compounds were limited to landfill property. There has been no reportable detection of these compounds in wells monitored outside of the landfill boundaries.

Waste Management has taken aggressive corrective measures to reduce the levels of these compounds, including the final capping in some areas and the installation of an extensive landfill gas collection system. The gas collection system has significantly reduced the presence of cadmium and vinyl chloride. We continue to expand the gas collection system as needed to minimize the presence of these compounds.

See the following links for additional, more technical information on the groundwater monitoring program: