The owners of Aquifer Protection Permits (APPs) are frequently required to include radionuclides in their list of analytes for their APP. The Arizona Department of Environmental Quality (DEQ) tries to set the limits at or below drinking water standards for these discharges from industrial plants and facilities. This can generate several problems.
All plants have people in them and they occasionally get sick and require tests that require radionuclides in Nuclear Medicine scans. Most of these radionuclides are excreted with in a few days of the study. These short-lived radionuclides pose no threat to the environment as they decay away long before they can reach groundwater, so the excreta from patients are unregulated both under federal rules (10 CFR 20 and 35), and state rules (R12). But they can spike a radionuclide (gross beta) sewer sample taken for an APP analysis. The unfortunate owner of the APP is then faced with a gross out-of-compliance value for their APP that is a product of a conflict between the absurdly low APP compliance limit (drinking water) for their discharge stream, and the state and federal rules on the release of radionuclides from licensed facilities administered by the NRC or the Arizona Radiation Regulatory Agency. Therefore, care should be taken to ensure that the APP is not written to conflict with the existing rules in 10 CFR 20 or R12. An APP for sewer discharge should not have any limit for gross beta, 90Sr or 3H in it for most cases, as these are governed under the ARRA rules listed above.
A second issue is the high salt content of many normal discharge streams. Virtually all natural radionuclides in water are salts, so any process that increases the salt content in the water (e.g. water based cooling systems or chillers) will also increase the natural radionuclides in the water. Uranium and radium are present in all waters, so they will increase with the total dissolved solids in the water. Again, this is not considered dangerous, as the high TDS waters dilute quickly in the sewer, and raw sewerage is plainly not potable. The MCLs for radionuclides in drinking water are very low, so it is quite easy to exceed the limits through normal operation of such mundane things as chillers. These considerations should also be factored into the establishment of APP radionuclide limits, if required.