## 4 Results and Discussion
### Dose Assessment and Hazard Indices  
Table 3 reports the calculated average values of adsorbed and effective doses together with the hazard indices. The absorbed gamma dose rate was estimated using Equation (4). Measured values range from 52 to 79 nGy h\({}^{-1}\), with an average value of 63 nGy h\({}^{-1}\). This average value is near the world mean value of 60 nGy/h [1], although 66% of the analyzed samples showed values that are in excess than the world mean. The variability of the adsorbed and effective doses is attributable to the different lithologic components of the considered areas. Equation (5) was used to evaluate the annual outdoor effective dose due to the activities of \({}^{226}\)Ra, \({}^{232}\)Th and \({}^{40}\)K in the analyzed samples. The obtained values range from 0.064 to 0.097 mSv y\({}^{-1}\), with an average value of 0.078 mSv y\({}^{-1}\). In a similar way, the annual indoor effective dose (Equation (6)) ranges from 0.070 to 0.323 mSv y\({}^{-1}\), with a mean value of 0.111 mSv y\({}^{-1}\). The total average annual effective dose is therefore of 0.189 mSv y\({}^{-1}\). This value is lower than the worldwide average of annual effective dose (0.48 mSv y\({}^{-1}\)[1]). The mean value is also lower than 1 mSv y\({}^{-1}\), which is set as the maximum limit by Reference [31]. The radium equivalent activity (Ra\({}_{\text{eq}}\)) was calculated using Equation (7) in order to determine the suitability of the samples when they are used as components in building materials. The obtained Ra\({}_{\text{eq}}\) values vary from 52 to 79 Bq kg\({}^{-1}\) with an average value of 63 Bq kg\({}^{-1}\), which is lower than 370 Bq kg\({}^{-1}\) set as the upper limit for building materials [29]. This indicates that the investigated samples may not be hazardous if used in the field of civil construction. The minimum value of radium equivalent activity was obtained \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Scheme 1.**} & **Absorbed** & **Effective Dose** & **Effective Dose** & \multirow{2}{*}{\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{} \end{tabular} } & **Annual Gonadal** \\  & **Dose Rate** & **Outdoors** & **Indoors** & **(Bq kg\({}^{-1}\))** & & & **Equivalent Dose** \\  & **(nGyh\({}^{-1}\))** & **(mSv y\({}^{-1}\))** & **(mSv y\({}^{-1}\))** & **(mSv y\({}^{-1}\))** & & & & **(AGED) (\(\mu\)Svy\({}^{-1}\))** \\ \hline
1 & 66 & 0.081 & 0.323 & 66 & 0.35 & 0.39 & 0.52 & 481 \\ \hline
2 & 63 & 0.077 & 0.084 & 63 & 0.33 & 0.39 & 0.50 & 457 \\ \hline
3 & 66 & 0.080 & 0.088 & 65 & 0.36 & 0.41 & 0.52 & 471 \\ \hline
4 & 52 & 0.064 & 0.070 & 52 & 0.28 & 0.33 & 0.42 & 378 \\ \hline
5 & 56 & 0.068 & 0.075 & 55 & 0.30 & 0.36 & 0.44 & 400 \\ \hline
6 & 58 & 0.072 & 0.079 & 58 & 0.33 & 0.40 & 0.46 & 418 \\ \hline
7 & 63 & 0.077 & 0.085 & 63 & 0.35 & 0.43 & 0.50 & 450 \\ \hline
8 & 79 & 0.097 & 0.106 & 79 & 0.44 & 0.53 & 0.63 & 566 \\ \hline
9 & 70 & 0.086 & 0.094 & 69 & 0.38 & 0.44 & 0.55 & 506 \\ \hline Mean & 63 & 0.078 & 0.111 & 63 & 0.35 & 0.41 & 0.50 & 458 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Radiological indices in the investigated sampling sites. for the river sediments come from the site ID4 (Reggio Cal.-Calopinace river), while the maximum one characterizes the samples collected at the site ID8 (Siderno-Novito river). The external and internal hazard indices, given by Equations (8) and (9), are lower than the unity for all investigated samples, thus the radiological risks can be considered negligible. The activity concentration index, calculated with Equation (10), is again lower than the unity for all analyzed samples. Thus, these river sediments are not be of concern to be used as construction materials. The obtained values of annual gonadal equivalent dose (AGED), calculated by Equation (11), range from 378 (site ID4) to 566 \(\mu\)Sv y\({}^{-1}\) (site ID8), with an average of 458 \(\mu\)Sv y\({}^{-1}\), for the investigated samples.