Journal of Environmental Protection, 2020, 11, 257-268 https://www.scirp.org/journal/jep ISSN Online: 2152-2219 ISSN Print: 2152-2197 DOI: 10.4236/jep.2020.114015 Mar. 27, 2020 257 Journal of Environmental Protection Destructive and Nondestructive Determination of 226 Ra and 228 Ra in Drinking Water by Gamma Spectrometry A. J. Khan 1 , A. Bari 1 , M. A. Torres 1 , D. K. Haines 1 , T. J. Hoffman 1 , T. M. Semkow 1,2 1 Wadsworth Center, New York State Department of Health, Albany, NY, USA 2 Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Rensselaer, NY, USA Abstract The Safe Drinking Water Act (SDWA) mandates that the drinking water should be monitored for 226 Ra and 228 Ra isotopes and establishes the Maxi- mum Contaminant Level of 185 mBq/L (5 pCi∙L −1 ) for the sum. In addition, SDWA regulates the Detection Limit (DL) of 37.0 mBq/L (1 pCi/L) for each isotope. The purpose of this work is to develop a working method for the de- termination of radium isotopes in drinking water satisfying the regulatory requirements of U.S. Environmental Protection Agency by utilizing our ex- tensive experience in low-background gamma spectrometry at this laborato- ry. Two versions of the method were studied: destructive and non-destructive. Destructive method used the BaSO 4 coprecipitation as well as 133 Ba tracer for chemical recovery. We have used three gamma spectrometers: low-background 102% and 134% efficient with top muon guards, as well as an ultra- low-background 140% efficient with full muon guard. We obtained a range of DLs from 5.3 to 22.6 mBq/L for 226 Ra and from 7.4 to 30.4 mBq/L for 228 Ra using the destructive method. For non-destructive method, the DL range was 26.0 to 26.9 mBq/L for 226 Ra and 27.6 to 28.6 mBq/L for 228 Ra using the 140% detector. To verify the methods, 7 to 10 laboratory control samples were spiked with both 226 Ra and 228 Ra at two different activities of 37.0 and 185 mBq/L. The results were evaluated by performing a combined loca- tion/variance chi-square test at a right-tail significance of 0.01 (99% Confi- dence Level), as stipulated by EPA. The verification results passed the chi-square tests at both activity levels. The destructive method can be accom- plished using low-background gamma spectrometry, whereas non-destructive method requires ultralow-background gamma spectrometry. How to cite this paper: Khan, A.J., Bari, A., Torres, M.A., Haines, D.K., Hoffman, T.J. and Semkow, T.M. (2020) Destructive and Nondestructive Determination of 226 Ra and 228 Ra in Drinking Water by Gamma Spectrometry. Journal of Environmental Protection, 11, 257-268. https://doi.org/10.4236/jep.2020.114015 Received: February 15, 2020 Accepted: March 24, 2020 Published: March 27, 2020 Copyright © 2020 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access