Under USEPA radionuclide sampling frequency for entry point testing, if results are greater than or equal to one-half the MCL and less than the MCL, sampling frequency is every how many years?

• A. 6 years
• B. 3 years
• C. 9 years
• D. 12 years

Answer: (A)

Radionuclide monitoring schedules are set by how close the detected levels are to the maximum contaminant level. When the test result is at least half the MCL but still below the MCL, the required sampling interval is six years. This places a moderate monitoring cadence: not as frequent as when levels approach or reach the MCL, but still enough to detect any upward trend before they reach the limit. If results are below half the MCL, monitoring is even less frequent, and if results reach or exceed the MCL, monitoring becomes more frequent to quickly catch any rise.