Incorporation of 40 CFR 192 as an ARAR when Implementing MARSSIM (USACE Input to the MARSSIM Committee for MARSSIM Revision 2) - 18526

One example special case for Final Status Surveys (FSSs) occurs at Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA) sites at which the radioactive materials are from the processing of uranium or thorium ores for their source material content. At these sites, EPA's Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings, in 40 CFR 192, are applicable. Also, 40 CFR 192 may be invoked at non-UMTRCA sites through the CERCLA as an Applicable or Relevant and Appropriate Requirement (ARAR) due to the presence of radium (Ra)-226 or Ra-228, even though the source of residual radioactive material was not a uranium or thorium mill tailings facility. However, the regulatory requirements in these standards infringe on some of the recommendations in the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). Specifically, the soil cleanup standards for Ra-226 or Ra-228 are specified as averages over an area of 100 square meters (m²). Note that in the 40 CFR 192 rulemaking, an averaging area of 100 m² was used as a reasonable footprint for a home. One goal of the 40 CFR 192 standards was to protect future homes from indoor radon, and the specified averaging area was a component implemented for the protection of health. In addition, 40 CFR 192 is silent regarding elevated measurement criteria (EMC)-type requirements for smaller areas of elevated radioactive material within the 100-m² footprint. At UMTRCA sites and CERCLA sites where UMTRCA is an ARAR, the following approach for FSSs is acceptable: - Survey units (SUs) may be classified, as appropriate, and survey activities may be adjusted accordingly for Class 1, Class 2, or Class 3 SUs. - Class 1 soil SUs should provide for evaluation of portions that are no greater than 100 m² in size, consistent with the 40 CFR 192 standards. - Class 2 and 3 soil SUs are not expected to exceed the 40 CFR 192 soil cleanup standard, so they do not require evaluation of portions that are no greater than 100 m² in size. - Compliance with 40 CFR 192 can be demonstrated through analysis of soil samples or composite soil samples from each SU, in conjunction with gamma radiation scanning or in situ gamma radiation measurements of each SU. When appropriate, these gamma radiation scans or in situ measurements correlated to soil sampling may be used in place of soil sampling. - By demonstrating that the average over 100 m² meets the 40 CFR 192 soil cleanup standard, the EMC criteria for small elevated areas of activity are not required for the purposes of MARSSIM, but may be developed. These minor modifications to the standard MARSSIM radiological survey approach are acceptable for UMTRCA sites or CERCLA sites where UMTRCA is an ARAR. (authors)