EPA Publishes New Radionuclides Rule

The recently released new drinking water standards for non-radon radionuclides could cost U.S. community water systems more than $80 million and would impact approximately 800 systems nationwide, according to figures released by the Environmental Protection Agency.

EPA published the Radionuclides Rule in December, revising the current radionuclides regulation which has been in effect since 1977. The new rule sets a Maximum Contaminant Level (MCL) standard of 30 micrograms per liter for uranium and 5 pCi/L for combined radium 226/228. It also set standards of 15 pCi/L for adjusted gross alpha particles, and 4 mrem/year for beta particles and photon radioactivity. The Maximum Contaminant Level Goals (MCLGs) for all of the radionuclides is zero.

Best available technologies for combined radium 226/228 is listed as ion exchange, lime softening and reverse osmosis. Those technologies plus enhanced coagulation/filtration can be used for removal of uranium.

Community water systems (CWSs) that serve at least 15 service connections or 25 residents regularly year round are required to meet the final MCLs and to meet the requirements for monitoring and reporting.

EPA anticipates the new uranium standard will cost utilities approximately $50 million, compared with $26 million for the radium-228 monitoring and mitigation costs. Monitoring, reporting, record keeping and administration costs are expected to total approximately $5 million.

The rule will become effective in December 2003. New monitoring requirements will be phased-in between that date and the beginning of the next Standardized Monitoring Framework period, December 31, 2007.

The final rule includes provisions that will require water systems to monitor water at all entry points into the system. Under the 1976 rule, water systems with multiple entry points to the distribution system were not required to test at every entry point, but rather to test at a "representative point to the distribution system." While the 1976 requirement did ensure that the "average customer" was protected, it did not ensure that all customers were protected, EPA said.

The new standard for uranium in drinking water will result in reduced uranium exposures for 620,000 people. The requirements for radium-228 is expected to result in reduced exposure to 420,000 people.

Exposure to radionuclides from drinking water can increase the risk of cancer. Radioactive particles (alpha, beta and gamma particles) emitted by radionuclides are called "ionizing radiation" because they ionize ("destabilize") nearby atoms as they travel through a cell or other material. In living tissue, this ionization process can damage chromosomes or other parts of the cell. This cellular damage can lead to the death of the cell or to unnatural reproduction of the cell. When a cell reproduces uncontrollably, it becomes a cancer. Certain elements accumulate in specific organs: radium accumulates in the bones and iodine accumulates in the thyroid.

For uranium, EPA considered not only the carcinogenic health effects from its radioactive decay and the decay of its daughter products ("radiotoxicity"), but also damage to the kidneys from exposure to the uranium itself ("chemical toxicity"). Exposure to elevated uranium levels in drinking water has been shown to lead to changes in kidney function that are indicators of potential future kidney failure.

Most drinking water sources have very low levels of radionuclides. Naturally occurring radionuclides are found in the Earth's crust and are created in the upper atmosphere. For example, trace amounts of long-lived isotopes (e.g., uranium-238, which has a half-life of almost five billion years) have been present in the earth's crust since the crust was formed. As these long-lived trace radionuclides decay, shorter-lived, more radioactive daughter products are formed. Of particular concern are naturally occurring uranium and the naturally occurring radium isotopes, radium-226 and radium-228, which have been observed to accumulate to levels of concern in drinking water sources.

Radionuclide levels tend to be higher in ground water than in rivers and lakes. While most water systems do not have detectable radionuclide activities, there are some areas of the country that have levels significantly higher than the national average. For example, some areas of the Midwest have elevated radium-226 levels and some western states have elevated uranium levels.

Over 96 percent of the cost of this final rule is expected to come from the mitigation of radionuclide levels through treatment, purchasing water, developing alternate water sources, and other compliance measures. For systems that need to take corrective action to comply with the new rule, the annual costs per system will range from $9,000 annually for the smallest community water systems to over $150,000 annually for systems serving 3,300 to 10,000, and over $500,000 annually for larger systems.

EPA estimates that households served by large water systems required to take action will experience increased water bills of less than $30 per year. Households served by typical small water systems (those serving 10,000 persons or fewer) will experience increased water bills of $50 - $100 per year. Costs will vary depending on the system size.

The requirement for separate radium-228 monitoring is expected to result in the avoidance of 0.4 cancer cases per year, with estimated monetized health effects benefits of $2 million annually. Water mitigation for radium also tends to reduce iron and manganese levels and hardness, which also has significant associated benefits.

The kidney toxicity benefits for the uranium standard can not be quantified because of limitations in existing health effects models at levels near the MCL. In addition to these non-quantified kidney toxicity benefits, 0.8 cancer cases per year are expected to be avoided, with estimated monetized cancer health effects benefits of $3 million annually. Water mitigation for uranium also removes other contaminants, which has associated benefits.

For general information on radionuclides in drinking water, contact the Safe Drinking Water Hotline, at (800) 426-4791, or visit the EPA Safewater website at http://www.epa.gov/safewater or the radionuclides website at http://www.epa.gov/safewater/radionuc.html.