# Radon Levels of Water Sources in the Southwest Coastal Region of Peninsular Malaysia
## 3 Results and Discussion  
In this study of 27 samples of water taken from different sources, the measured radon concentrations are given in Table 1, with an average value of 21.21 \(\pm\) 1.67 Bq l\({}^{-1}\). The lowest radon concentration in water was recorded for the sampling location M15 (Durian Tunggal, Malacca), while the highest concentration of radon was recorded from the sampling location N6 (Chengkau, Negeri Sembilan). It is suggested that the variations in concentration are affected by factors including uranium and associated radium contents in the aquifer, the nature of the basement rocks, the solubility and mobility of parent radionuclides in the study area, climatic conditions, transport processes, depth of aquifers, as well as various other hydrogeological conditions [4; 14; 21; 22; 23]. \begin{table}
\begin{tabular}{c c c c} \hline \hline  
A further analysis of radon concentration was compiled based on the categories of water sources, and the results are displayed in Figure 4. The average radon concentration in hot spring water was the highest, i.e., 98.56 \(\pm\) 5.88 Bq l\({}^{-1}\), followed by groundwater, with an average radon concentration of 32.36 \(\pm\) 1.8 Bq l\({}^{-1}\). The lowest average radon concentration was 1.95 \(\pm\) 0.61 Bq l\({}^{-1}\), recorded for tap water. For the hot spring water, the radon concentration is the lowest, albeit of a similar order to that reported in Thailand, Rachaburi Province, which was from 95 to 154 Bq l\({}^{-1}\)[24], with differences in geological formation and soil types, i.e., Rachaburi being of igneous and sedimentary types [25] while the geological formation in the present study area is triassic, dominated by sedimentary rocks. Elsewhere, in northern Venezuela, the concentration of radon in hot spring water has been reported to be in a wider range, i.e., from 1 to 560 Bq l\({}^{-1}\)[26], the various influencing factors being as discussed herein as well as elsewhere [27; 28; 29]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sampling Code** & **Location and Coordinates** & **Water Sources** & \begin{tabular}{c} **Radon Concentration** \\ **(Bq l\({}^{-1}\))** \\ \end{tabular} \\ \hline N6 & \begin{tabular}{c} Chengkau \\ (2.543, 102.137) \\ \end{tabular} & Hot spring & 186.5 \(\pm\) 12.18 \\ \hline N7 & \begin{tabular}{c} Batu Kikir \\ (2.894, 102.287) \\ \end{tabular} & Tap water & 1.33 \(\pm\) 0.53 \\ \hline N8 & \begin{tabular}{c} Simpang Durian \\ (3.096, 102.217) \\ \end{tabular} & Tap water & 3.98 \(\pm\) 1.02 \\ \hline N9 & \
\begin{tabular}{c} Kuala Klawang \\ (2.992, 102.071) \\ \end{tabular} & Tap water & 0.88 \(\pm\) 0.69 \\ \hline N10 &
\begin{tabular}{c} Senawang \\ (2.69, 101.991) \\ \end{tabular} & Tap water & 1.35 \(\pm\) 0.73 \\ \hline Average & - & - & 21.21 \(\pm\) 1.67 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(Cont.\)  
Figure 4: Average radon concentrations in water sources of the southwest coastal region of Peninsular Malaysia. In this study, the groundwater radon concentration is greater than the average radon concentration recorded by a study conducted in Rajasthan that also used a RAD7 detector [30]. In another study conducted in Gadau, Nigeria [14], the radon concentration ranged from 4.92 to 82.89 Bq l\({}^{-1}\) with a mean value of 38.3 Bq l\({}^{-1}\); potential factors, additional to those previously alluded to, included the minerals derived from the aquifer rocks such as uranium mineralization in granites, graisess, and quartztite rocks, as well as the presence of faults and shears at the study areas [30; 31]. In regard to the relatively low radon concentration for tap water, in this study, the averaging was 1.95 \(\pm\) 0.61 Bq l\({}^{-1}\) as compared with the average of 5.37 \(\pm\) 0.58 Bq l\({}^{-1}\) reported in Sungai Petani, Kedah [32] and 10.82 Bq l\({}^{-1}\) reported in Turkey [22].