## 2 Material and Methods
### Sampling and Processing  
As part of the research work in 2017-2018, 21 soil samples were collected from the Poleski National Park. In order to obtain a homogeneous measurement grid, the points were chosen to be distributed at similar distances. Most of the points were located in accessible places, close to landmarks or tourist routes. Figure 1 shows an illustrative map of the PNP along with the names and locations of soil sampling points. On the other hand, the geographical coordinates of the measurement points are presented in Table 1. \begin{table}
\begin{tabular}{l l l l} \hline
**Site** & **Name of Point** & **Attitude** & **Longitude** \\ \hline
1 & Astrosciezka & 51\({}^{\circ}\)25\({}^{\prime}\)13\({}^{\prime\prime}\) & 23\({}^{\circ}\)9\({}^{\prime}\)58\({}^{\prime\prime}\) \\ \hline
2 & [PERSON] & 51\({}^{\circ}\)25\({}^{\prime}\)59\({}^{\prime\prime}\) & 23\({}^{\circ}\)3\({}^{\prime}\)32\({}^{\prime\prime}\) \\ \hline
3 & Ciek Zienkowski & 51\({}^{\circ}\)28\({}^{\prime}\)35\({}^{\prime\prime}\) & 23\({}^{\circ}\)6\({}^{\prime}\)28\({}^{\prime\prime}\) \\ \hline
4 & [PERSON] & 51\({}^{\circ}\)22\({}^{\prime}\)41\({}^{\prime\prime}\) & 23\({}^{\circ}\)16\({}^{\prime}\)57\({}^{\prime\prime}\) \\ \hline
5 & [PERSON] & 51\({}^{\circ}\)20\({}^{\prime}\)41\({}^{\prime\prime}\) & 23\({}^{\circ}\)16\({}^{\prime}\)55\({}^{\prime\prime}\) \\ \hline
6 & Dab Dominik & 51\({}^{\circ}\)26\({}^{\prime}\)57\({}^{\prime\prime}\) & 23\({}^{\circ}\)7\({}^{\prime}\)10\({}^{\prime\prime}\) \\ \hline
7 & [PERSON] & 51\({}^{\circ}\)21\({}^{\prime}\)9\({}^{\prime\prime}\) & 23\({}^{\circ}\)19\({}^{\prime}\)16\({}^{\prime\prime}\) \\ \hline
8 & Las Tafle & 51\({}^{\circ}\)25\({}^{\prime}\)51\({}^{\prime\prime}\) & 23\({}^{\circ}\)11\({}^{\prime}\)36\({}^{\prime\prime}\) \\ \hline
9 & Lipniak & 51\({}^{\circ}\)27\({}^{\prime}\)42\({}^{\prime\prime}\) & 23\({}^{\circ}\)9\({}^{\prime}\)15\({}^{\prime\prime}\) \\ \hline
10 & Laka Pokrzywnik & 51\({}^{\circ}\)20\({}^{\prime}\)22\({}^{\prime\prime}\) & 23\({}^{\circ}\)20\({}^{\prime}\)11\({}^{\prime\prime}\) \\ \hline
11 & Mietiuka & 51\({}^{\circ}\)27\({}^{\prime}\)51\({}^{\prime\prime}\) & 23\({}^{\circ}\)16\({}^{\prime}\)8\({}^{\prime\prime}\) \\ \hline
12 & Ostoja Poleska & 51\({}^{\circ}\)25\({}^{\prime}\)8\({}^{\prime\prime}\) & 23\({}^{\circ}\)5\({}^{\prime}\)45\({}^{\prime\prime}\) \\ \hline
13 & Piwonica & 51\({}^{\circ}\)24\({}^{\prime}\)38\({}^{\prime\prime}\) & 23\({}^{\circ}\)3\({}^{\prime}\)53\({}^{\prime\prime}\) \\ \hline
14 & Puszczyk Mszarny & 51\({}^{\circ}\)27\({}^{\prime}\)22\({}^{\prime\prime}\) & 23\({}^{\circ}\)13\({}^{\prime}\)59\({}^{\prime\prime}\) \\ \hline
15 & Sciezka Splawy & 51\({}^{\circ}\)24\({}^{\prime}\)32\({}^{\prime\prime}\) & 23\({}^{\circ}\)5\({}^{\prime}\)46\({}^{\prime\prime}\) \\ \hline \end{tabular}
\end{table} 
Table 1: Geographical coordinates recorded of the sampling points in the Poleski National Park. Figure 1: Laboratory equipment. Sampling was performed in accordance with the methodology used by the Central Laboratory for Radiological Protection (CLOR) for the needs of radiological monitoring of soils in Poland. The methodology was approved by the president of the National Atomic Energy Agency and the Inspectorate for Environmental Protection. Samples were taken from the toposoil (0-10 cm). For this purpose, steel dies with cylinder geometry and diameter d \(\approx\) 7 cm were used. At each measurement point, 7 portions of the soil were collected: 1 portion from the center and 6 from the circumference of a circle 2 m in diameter, equally spaced from each other (forming a regular hexagon). Then, the portions were poured into one bag for each collection point. The bags were labeled (name of the point, geographical coordinates, date and time of collection) and then transported to the CLOR Dosimetry Department [35]. Soil samples were prepared in stages for radiation and heavy metal studies. The first stage consisted of pouring the soil onto the sheets and removing plant fragments, roots, and stones. Then, the soil was ground and labeled.