Metro Wastewater Reclamation District (Metro), the wastewater treatment agency for most of metro Denver, collects and treats about 140 million gallons per day (MGD) of wastewater at the Robert W. Hite Wastewater Treatment Plant. The treated effluent is discharged to the South Platte River in compliance with State and federal requirements. Treated groundwater from Lowry Landfill is discharged to Metro, following an exhaustive scientific review that determined Metro could accept this water and still produce effluent that protects all of the uses of the South Platte River, including aquatic life, drinking water supply, recreation and agriculture. This discharge represents 0.026% of the 140 MGD treated by Metro.
Numerous analyses have been performed by both Lowry Landfill and Metro since Lowry Landfill began discharging treated groundwater in July 2000. Furthermore, extensive scientific testing by the U.S. Environmental Protection Agency (EPA) over more than a decade has not identified any elevated risk from the Lowry discharge, and there is no evidence that significant radioactive waste was ever disposed of at Lowry Landfill. Studies have consistently shown that there is no increased risk of exposure to radioactive and other hazardous materials from the Lowry groundwater discharged to Metro.
The response to allegations regarding radioactive contamination of Denver Water's recycled water is below:
Response to Allegations Regarding Possible Radioactivity in Discharge from Lowry Landfill That Would Impact Recycled Water
Posted 11/17/03
There have been allegations that recycled water might be unsafe. The theory behind the allegations appears to be that Lowry Landfill received radioactive waste, that the groundwater collected at Lowry and treated at the Robert W. Hite wastewater treatment plant ('Metro') is radioactive, that effluent leaving Metro is radioactive, and that Denver Water's recycled water will be radioactive as a result.
Complaints based on these same allegations were raised to the proper authorities several years ago and were disproved at various times, most conclusively in December 2002. Nevertheless, the allegations persist.
Documents from the U.S. Environmental Protection Agency (EPA) dated December 2002 explain why EPA has determined not to proceed any further with a plan for additional monitoring of radionuclides in Lowry discharges to the WWTP. Max Dodson, who was then the EPA Assistant Regional Administrator, stated, "The current groundwater monitoring data simply does not support the need to go forward with the plan at this time."
Here is a brief history and highlights gleaned from an EPA memorandum dated December 5, 2002, and Max Dodson's decision letter dated December 13, 2002.
- From 1985-1993 EPA and responsible parties studied Lowry Landfill to characterize the contamination at the site.
- In 1991, a consultant at the site issued a report of levels of americium and plutonium at Lowry that were higher than at Rocky Flats.
- In 1992, the same consultant issued another report after most of the samples were re-analyzed. "There was NO CASE in which the presence of transuranics was positively confirmed."
- In 1994, EPA issued its Record of Decision (ROD) on Lowry Landfill, requiring containment and treatment of groundwater on site. Despite the poor quality of the 1991 data, EPA used the data in its risk assessment. The risk assessment concluded that the total risk from naturally-occurring and transuranic radionuclides at Lowry was less than the risk from estimated national background exposure.
- In 1996 the Colorado Citizen Action Network (CCAN), Stop the Sludge Campaign - expressed concern that plutonium from Rocky Flats had been disposed of at Lowry.
- In 1997, EPA amended the ROD to allow pretreatment of groundwater at Lowry, followed by conveyance to Metro for further treatment. The pretreatment permit requires that the discharge at Lowry be sampled twice a month for plutonium, americium, gross alpha and gross beta. In over 400 samples from March 2000 to December 2001, there was only one exceedance for gross alpha and gross beta (none for plutonium and americium), and those exceedances were not repeated. "The preponderance of the data suggests that there is no plutonium or americium in the discharge to Metro (WWTP) that would render a risk to the worker."
- The 1997 amendment of the ROD "created a surge of concern" from the CCAN, leading to a two-year audit by EPA's Inspector General.
- CCAN alleged that high levels of radionuclides were present at Lowry; groundwater contaminated with plutonium would be pumped to Metro (WWTP); and EPA Region 8 and others had conspired to cover-up radionuclides at Lowry.
- In 2000, the Inspector General issued a formal report, which "found no apparent credible evidence that any of these conditions existed."
- In addition to monitoring the discharge from Lowry to Metro, EPA has early warning wells at Lowry located upstream of the groundwater collection point, which monitor water quality six months prior to collection. In samples collected once a quarter, none showed problems.
- The wells that the 1991 consultant reported being radioactive were resampled (in 2001 or 2002). "All render results of americium and plutonium near zero activity."
"In conclusion, [EPA has] found no evidence to support the need to launch an intensive study to determine the level of man-made radionuclides off-site as there is no current risk from the levels of activity detected on-site and within the discharge waters."
Untreated groundwater from the Lowry Landfill has not increased risk of exposure to radioactivity beyond the risk associated with naturally occurring background levels of radiation. There is no additional risk in the water being discharged to the WWTP after pretreatment or in the much diluted effluent being discharged from the WWTP into the South Platte River. Therefore, there is no additional risk from effluent diverted and treated at Denver Water's Recycle Plant.
More Information
For more information on Denver Water's Recycle Plant, contact Abigail Holmquist at 303-628-7010 or abigail.holmquist@denverwater.org.
To request a copy of the EPA's report on the Lowry Landfill, please contact:
EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202-1129
(303) 312-6473 or
1-800-227-8917 ext. 6473