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Inside NRC
(c) 2005 McGraw-Hill, Inc.
Monday, February 7, 2005
Volume 27, Number 3

INTERNATIONAL REGULATION

NRC Denies 1993 Petition To Change Wastewater Release Requirements

Tom Harrison, Washington

After more than a decade of research, NRC has denied a petition asking the agency to require licensees to provide at least 24 hours' notice to a sewage treatment plant before releasing radioactive material into a sewer system. NRC said the change was unnecessary because existing regulations are adequate.



The petition was filed Aug. 2, 1993 by the Northeast Ohio Regional Sewer District, which said one of its three wastewater treatment centers had been contaminated from releases of radioactive material containing cobalt-60 into its sanitary sewer system. It estimated the resulting characterization and remediation would cost more than $1-million at least.



NRC commissioners approved Dec. 20, 2004 the staff's Nov. 30, 2004 recommendation to deny the petition. A notice of the denial was published in the Jan. 27, 2005 Federal Register.



In its recommendation to the commissioners (Secy 04-226), NRC staff said the process took so long because it wanted to collect sufficient data nationally to make a determination about whether NRC regulations were sufficient to protect public health and safety.



Data collection



In May 1991, NRC changed the release criteria and reduced concentration limits for release of licensed material into sanitary sewer systems (10 CFR 20.2003) as part of a major revision to its Part 20 regulations. Licensees were allowed to defer implementation until Jan. 1, 1993. The district's contamination was found in April 1991, prior to the revised concentration limits being fully implemented. In its petition, the district said radioactive contamination had also occurred at treatment plants in New York, Michigan, Tennessee, Pennsylvania, and Washington, D.C.



Under the revised regulations, the concentration limits for radionuclides released into a sanitary sewer system were reduced by a factor of 10 as part of an overall reduction in effluent release limits, NRC said. The reduction was due to past contamination incidents involving Co-60 and americium-241. NRC said the revised concentration limits were an effort to reduce the public's exposure to radionuclides released into the sanitary sewer system.



Also, NRC recommended that licensees should set as low as reasonably achievable (Alara) goals for effluents at 10%-20% of their allowable limits. NRC said it conducts periodic inspections to ensure licensees are in compliance with regulations.



In October 1993, NRC began soliciting public comments on the district's petition. NRC said the district's petition did not include supplementary information or supporting data. The agency said it wanted to gain a nationwide perspective on the potential issue of licensed material being concentrated in sewer sludge.



In February 1994, NRC published an advanced notice of public rulemaking to solicit comments on whether its regulations needed to be amended regarding releases of radionuclides from NRC licensed facilities into sanitary sewer systems, based on current sewer treatment technologies.



In May 1994, the General Accounting Office (now called the Government Accountability Office), or GAO, issued a report on contamination being found in sewage sludge or ash or in wastewater collection systems. In June 1994, a joint House-Senate hearing was held, prompted by concerns associated with elevated levels of radioactivity in incinerator ash at the Cleveland treatment plant referred to in the district's petition.



At the hearing, EPA and NRC committed to jointly develop guidance for publicly owned treatment works (POTWs) and to collect more data on the concentration of radioactive materials in samples of sewage sludge and ash from POTWs nationwide.



Between 1994 and 1997, federal, state and industry studies were conducted to assess reconcentration of radioactive materials that are released in sanitary sewer systems. An NRC report in December 1994 found that radioactive materials were reconcentrated as a result of wastewater treatment. However, it said the extent of the condition was difficult to determine because the degree of reconcentration was radionuclide-specific and was influenced by the wastewater treatment processes used. The report said data were not sufficient to assess the adequacy of the revised regulations in preventing occurrences of radionuclide concentrations in sewage sludge at levels that presented an undue risk to the public. It also said available data were not sufficient to suggest strategies for changing the regulations.



In 1996, the Association of Metropolitan Sewerage Agencies surveyed 55 wastewater treatment plants in 17 states and found that the most significant sources of radioactivity were naturally occurring radioactive materials (NORM). In 1997, the Washington State Department of Health issued a report that concluded that doses from radionuclides in sewage sludge are extremely low compared to background or to generally accepted regulatory dose limits. It also said there is no indication that radioactive sludge poses a public health and safety risk.



However, the scope of such studies was limited, so an extensive, nationwide survey was needed to confirm their findings on a wider scale, NRC staff said.



In 1996, the Interagency Steering Committee of Radiation Standards (ISCORS) formed the Sewage Sludge Subcommittee to coordinate efforts concerning radioactive materials in sewage sludge and address the recommendations in the 1994 GAO report.



NRC co-chaired the subcommittee with the Environmental Protection Agency (EPA). A representative from the Ohio sewer district was a member, also. Between 1998 and 2000, the subcommittee conducted a survey of POTW sewage sludge and ash to help assess the potential need for NRC and/or EPA regulatory decisions, NRC staff said.



ISCORS issued a final report in November 2003 on radiological survey results and analysis of radioactivity in sewer sludge. ISCORS is finalizing two related reports, on modeling to assess radiation doses recommendations on management of radioactive materials in sewer sludge and ash at POTWs.



The ISCORS reports concluded that no excessive concentrations of radioactive material were observed in the sewage sludge or ash and that no widespread concern to public health and safety was identified, the staff said. Based on those findings, the staff recommended the commission deny the petition.



Changes rejected



NRC staff said the rationale that public health and safety would be enhanced by the advance notification was not supported. Both the ISCORS survey report and dose modeling report have shown that doses from radionuclides in sewage sludge are generally low compared to background and to generally accepted regulatory dose limits, the staff said.



Nationally, the most significant levels of radioactivity in POTWs are associated with NORM, rather than licensed material, it said.



"A regulatory burden that would impact thousands of licensees with no apparent benefit regarding public health and safety should not be imposed because of isolated occurrences of radioactive material detected at sewage treatment plants," the staff said.



The staff also said the requested change would not be "effective, efficient or realistic." It cited several public comments that advance notification would be impractical, if not impossible, because most releases are continuous and involve very small quantities of radioactive material.



The NRC also denied the district's request to remove a requirement for NRC approval prior to incineration of licensed radioactive materials that enter the sanitary sewer system.



A change is not needed, NRC said. It cited studies, surveys and modeling efforts that indicate releases of radioactive material from licensed materials in accordance with regulations generally do not reconstitute in sewage sludge in sufficient concentrations to pose a risk to public health and safety.