# A New Radiological Risk Containment Procedure in Potentially Contaminated Areas
## 3 Results and Discussion  
The average value of the environmental radioactivity background measured in the investigated area was (96 \(\pm\) 7) nGy h\({}^{-1}\), in good agreement with the average values in the same area reported in the literature [24] (RADREM--stage 1). Measurements of the absorbed dose rate made possible the identification of a part of the asphalt road, consisting in an area of about 30 m\({}^{2}\), affected by an important radiometric anomaly at some specific points, called \"hot spots\", where a significant increase in the environmental radioactivity background level was recorded (RADREM--stage 2). The \"hot spots\" sites are reported in Table 1, together with their IDs, GPS coordinates and average values of the measured absorbed dose rate. The identification of the \"hot spots\" allowed us to proceed to stage 3 of the RADREM: an in-depth study, performed through the use of the portable gamma spectrometer, with the \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Site ID**} & \multicolumn{2}{c}{**GPS Position**} & \multicolumn{1}{c}{\(\dot{D}\)} \\ \cline{2-4}  & **Latitude** & **Longitude** & **(uGy h\({}^{-1}\))** \\ \hline
1 & 38\({}^{\circ}\)42\({}^{\prime}\)39.06\({}^{\prime\prime}\) N & 38\({}^{\circ}\)42\({}^{\prime}\)39.12\({}^{\prime\prime}\) N & 1.6 \(\pm\) 0.1 \\
2 & 38\({}^{\circ}\)42\({}^{\prime}\)38.98\({}^{\prime\prime}\) N & 38\({}^{\circ}\)42\({}^{\prime}\)40.81\({}^{\prime\prime}\) N & 0.4 \(\pm\) 0.1 \\
3 & 16\({}^{\circ}\)04\({}^{\prime}\)56.95\({}^{\prime\prime}\) E & 16\({}^{\circ}\)04\({}^{\prime}\)56.95\({}^{\prime\prime}\) E & 2.8 \(\pm\) 0.2 \\
4 & 16\({}^{\circ}\)04\({}^{\prime}\)57.07\({}^{\prime\prime}\) E & 16\({}^{\circ}\)04\({}^{\prime}\)57.10\({}^{\prime\prime}\) E & 4.8 \(\pm\) 0.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The ”hot spots” sites, together with their IDs, GPS coordinates and average values of the measured absorbed dose rate. Figure 2: The geolithological map, with the hydraulic risk levels (R#, # = 1,..., 4) indicated. aim to recognize the radioisotopes responsible for the radiometric anomaly. As shown in Figure 3, for the site ID1 as an example, the spectral analysis put into evidence the presence of \({}^{226}\)Ra in all the \"hot spots\", through the identification of its \(\gamma\)-line at 186.21 keV and those of its daughters \({}^{214}\)Pb and \({}^{214}\)Bi at 77.10 keV, 295.22 keV, 351.93 keV and 609.31 keV, respectively. After the identification of the radionuclide, the type of source was characterized. In this regard, a search for metal parts was carried out with a metal detector to exclude the presence of steel casings and drums and to support the hypothesis of free sources scattered in the area under investigation. The result of this search confirmed the absence of metal components, and then it was possible to exclude an important range of devices that contain radium, such as smoke detectors, heads of industrial appliances, pipes or ducts containing NORM in use in the phosphate or oil industry, etc. [25]. Phosphoric metasilicates, produced by a chemical industry in the Crotone municipality (about 140 km from the investigated area), and used in past years as filling materials for roads and for paving [26], were excluded because only a part of the asphalted road was affected by contamination, while in the other asphalted parts, only environmental background level was recorded. Then, the area was immediately banned and classified as contaminated by radionuclides (RADREM--stage 4). The intervention to contain the radiological risk was performed through an activity of excavation of the road surface, aimed at recovering the radioactive source. The operations brought to light a total of eight sources of \({}^{226}\)Ra. In particular, one, one half, two and almost five sources were found at the sites ID1, ID2, ID3 and ID4, respectively. They were without metal support, with some river stones and bitumen on it.