## 3 Results
### Quality Assurance/Quality Control (QA/QC) Summary  
Laboratory data quality was evaluated based on results from method blanks (MB), laboratory control samples (LCS), LCS duplicates (LCSD), matrix spikes (MS), and MS duplicates (MSD) using USEPA guidelines [7]. In the MBs, all \({}^{226}\)Ra and \({}^{228}\)Ra results were below their minimum detectable concentration (MDC). Data accuracy evaluation showed the percent recovery values for the LCS, LCSD, MS, and MSD were within recommended limits. Data precision evaluation showed that the relative percent differences (RPDs) for analytical duplicate samples and field duplicate samples were also within laboratory control limits for all analyses. Total \({}^{228}\)Ra was detected above the MDC in the field blank by Lab A and Lab B, and dissolved \({}^{226}\)Ra was detected above the MDC in the field blank by Lab C. Dissolved \({}^{228}\)Ra was also detected above the MDC in the field blank by Lab D. Sample results containing less than 10\(\times\) the amount found in the field blanks were qualified as being estimated with high bias (Table 3) and were assigned a J+ qualifier. Radiological data such as \({}^{226}\)Ra and \({}^{228}\)Ra are typically reported as the measured value \(\pm\) the degree of precision. When a value is below the MDC, the actual value is still reported but the datum is flagged as non-detect and the MDC is provided. The sum of the \({}^{226}\)Ra and \({}^{228}\)Ra is subsequently calculated to determine the combined Ra (\({}^{226}\)Ra + \({}^{228}\)Ra) that is typically used for compliance in the USA. If either of the \({}^{226}\)Ra or \({}^{228}\)Ra values are below detection, the value of the MDC for the non-detect value is summed with the \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Location**} & \multirow{2}{*}{**Lab**} & \multirow{2}{*}{\begin{tabular}{c} **226**Ra** \\ **(Dissolved)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **226**Ra** \\ **(Total)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **228**Ra** \\ **(Dissolved)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **228**Ra** \\ **(Total)** \\ \end{tabular} } \\ \hline \multirow{4}{*}{Impoundment} & A & 1.8 & 1.5 & 1.7 & 3.7 J+ \\  & B & 2.2 & 1.5 & \textless{}0.69 & 1 J+ \\  & C & 1.52 J+ & 1.56 & \textless{}0.61 & \textless{}0.69 \\  & D & 1.4 & 1.66 & \textless{}0.7 & \textless{}0.7 \\ \hline \multirow{4}{*}{\begin{tabular}{c} Well 176 \\ (Compliance) \\ \end{tabular} } & A & 0.7 & 0.8 & \textless{}1.9 & 4.1 J+ \\  & B & 0.97 & 0.74 & 3.2 & 3.2 J+ \\  & C & 1.37 J+ & 1.2 & 4.6 & 4.8 \\  & D & 0.965 & \textless{}0.356 & 5.2 J+ & 5.9 \\ \hline \multirow{4}{*}{\begin{tabular}{c} Well 176 \\ (Duplicate) \\ \end{tabular} } & A & 0.7 & 0.8 & 3 & 4.1 J+ \\  & B & 1.3 & 0.83 & 3.8 & 4.7 J+ \\  & C & 1.08 J+ & 0.96 & 3.9 & 5.1 \\  & D & 0.859 & 0.777 & 5.5 J+ & 7 \\ \hline \multirow{4}{*}{\begin{tabular}{c} Well 179 \\ (179 \\ \end{tabular} } & A & 0.5 & 0.5 & 1.9 & 1.5 J+ \\  & B & \textless{}0.66 & 0.58 & 1.7 & 4.8 J+ \\  & C & 0.77 J+ & 0.73 & 2.07 & 2.68 \\  & D & 0.334 & 0.639 & 3.7 J+ & 5.4 \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Well 182 \\ (Background) \\ \end{tabular} } & A & 0.3 & 0.3 & 2.9 & 3.3 J+ \\  & B & \textless{}1 & \textless{}0.57 & \textless{}0.75 & \textless{}0.55 \\ \cline{1-1}  & C & 0.4 J+ & 0.32 & \textless{}0.62 & \textless{}0.64 \\ \cline{1-1}  & D & \textless{}0.328 & 0.487 & 0.8 J+ & 1.8 \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Field Blank \\ \end{tabular} } & A & \textless{}0.2 & \textless{}0.2 & \textless{}1.4 & 2 \\ \cline{1-1}  & B & \textless{}1.1 & \textless{}0.55 & \textless{}0.63 & 1.4 \\ \cline{1-1}  & C & 0.28 & \textless{}0.25 & \textless{}0.51 & \textless{}0.63 \\ \cline{1-1}  & D & \textless{}0.249 & \textless{}0.234 & 0.8 & \textless{}0.7 \\ \hline \end{tabular}
\end{table} 
Table 3: Comparison of ILC results (pCi/L) for \({}^{226}\)Ra and \({}^{228}\)Ra \({}^{1}\). detectable value to calculate the \({}^{226}\)Ra + \({}^{228}\)Ra concentration.