Gamma Emitting Isotopes – Drinking Water


Gamma in Drinking Water

Requisition Form


Test Description The determination of gamma emitters in drinking water samples such as Cesium 134, Cesium 137, and Iodine 131. Gamma emitting isotopes with energies between 59.5 keV and 1836 keV can also be detected.

Pre-Approval Needed

Supplemental Information Required N/A
Supplemental Form(s) N/A
Performed on Specimens from (sources) Environmental
Sample/Specimen Type for Testing Potable water
Minimum Volume/Size Required Hard or soft plastic; 1 gallon + 1 liter
Storage/Preservation Prior to Shipping None - Sample must be submitted to the laboratory within 5 days of collection.
Transport Medium N/A
Specimen Labeling Label each bottle with a water proof marker. Pre-printing labels is acceptable. Sample identification must match submission form.
Shipping and Specimen Handling Requirements Sample must be submitted to the laboratory within 5 days of collection.
Method EPA 901.1
Turn-around Time Sample must be analyzed within 180 days of sample collection. The target sample turnaround time is 120 days from date of receipt.
Interferences/Limitations Due to short half-life of I-131, this method does not meet the required detection limit of 1.0 pCi/L.
Common Causes for Rejection
  • Insufficient quantity
  • unacceptable specimen type or source
  • improper shipping conditions
  • expired media or collection container
  • discrepancies between specimen label and submission form
  • incomplete or missing submission form
  • sample not received by the lab within 5 days of collection
Additional Information This method is routinely conducted as follow up to samples that exceed 50 pCi/L for gross beta radioactivity. This method can be conducted for other drinking water samples when requested.