The primary contaminant of concern at this Site is Radium-226. EPA and KDHE have documented Radium-226 concentrations in soil exceeding 5 pCi/g plus background (up to 109 pCi/g). Radium-226 is a hazardous substance as defined by section 101(14) of CERCLA, and is listed at 40 CFR § 302.4 as radionuclides.
Radioluminescent paint – a mixture of a radionuclide, usually Radium-226, and a phosphor, usually zinc sulfide – was developed in the early 1900s. The mixture was initially used on watch and clock faces and later adapted for use on instruments, most notably aircraft dials. As part of radium’s decay process, it emits an alpha particle that can excite the phosphor, which eventually releases a photon. The end results are dials that “glow” and can be read at night without light. Radium has 25 known isotopes, four of which occur in nature, with Radium-226, and to a lesser extent, Radium-228 being the most common. Radium-226 has the longest half-life at 1,602 years. Radium is a decay product of uranium and consequently is associated with uranium ores. Radium decays by emitting alpha and beta particles and gamma rays. Radium initially decays into radon, a heavy gas, which itself decays into other radioactive solids including polonium, bismuth, lead, and thallium. Radium in soils does not biodegrade.
Businesses, workers, and nearby residents at and near the former Site property or passersby may be exposed via routes of inhalation or dermal contact to loose soils in the parking areas. The greatest risk to humans from radium is through ingestion of food and water documented by the Agency for Toxic Substances and Disease Registry’s Toxicological Profile for Uranium, Section 5.5 (December 1990).
Exposure to high levels of radium results in an increased incidence of bone, liver, and breast cancer. Radium, like calcium, is retained in bone tissue; bone cancer is the greatest risk from radium exposure. Death and decreased longevity have been reported as a result of long-term exposure. Radium has also been shown to affect the blood (anemia), eyes (cataracts), and teeth (increased broken teeth and cavities). Emitted ionizing radiation from the decay of radium and its daughters can lead to skin damage, hair loss, birth defects, general illness, and cancer.
The objective of the removal action is to protect public health or welfare or the environment by responding to the release of hazardous substances and pollutants or contaminants into the environment as presented by soils contaminated with radium-226 at the Site. Contaminated soils that exceed 5.70 pico Curies per gram (pCi/g) plus background will be excavated and properly disposed of.
EPA conducted field activities for a RSE in June and December of 2011. Field screening with radiation detectors and radiation analysis of soil and groundwater samples further defined the lateral, vertical and aerial extent of contamination (all ground water samples collected, screened, and read, were below the EPA screening level of 5 pCi/g plus background (5.17 pCi/g) (PolReps 1 – 2 outline the removal assessment activities).
The Action Memorandum was signed on June 8, 2012, by Cecelia Tapia, Superfund Division Director, outlines the scope of work covered by the removal action. A fund lead removal action was initated on August 2, 2012 and EPA demobbed from the Site on August 29, 2012 (Polreps for this activity begin with #3 - #6). KDHE was notified of the initiation of removal action activities on August 1, 2012. Excavation and loading railcars, from all three remedial sites, with the contaminated material was completed by August 29, 2012. Approximately four railcars containing 125 tons of contaminated material was shipped to Clive, Utah. The transportation, treatment, storage and disposal of the hazardous substances, was done in accordance with all applicable local, state and federal requirements.
All identified areas at the site have been excavated, remediated and confirmed to meet the criteria for cleanup as outlined in the Action Memorandum. Radon monitoring sample results also confirmed radon levels at the site to be below the standard of 4 pCi/L.
