## 2 Materials and Methods
### Monitoring Network  
The monitoring system of the landfill site includes three basic elements: (1) groundwater; (2) surface water; and (3) leachates. Shallow piezometers and one deep well were installed in the  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Layer** & **Soil** & \(\mathbf{I_{1}}\) **or \(\mathbf{I_{0}}\)** & **Stratigraphy** & \(\mathbf{\rho}\) & \(\mathbf{k}\) \\ \hline I & clsSa & 0.4 & Quaternary (Pleistocene) & 2.1 & \(9.2\times 10^{-6}\) \\ II & Sa & 0.7 & Quaternary (Pleistocene) & 2.0 & \(5\times 10^{-5}\) \\ III & sacSi/Cl & 0.2 & Quaternary (Pleistocene) & 2.1 & \(1.2\times 10^{-7}\) \\ IV & saCl & 0.1 & Quaternary (Pleistocene) & 2.2 & \(3\times 10^{-8}\) \\ V & Cl/saCl & \textless{}0.25 & Tertiary (Ploicene) & 2.1 & \textless{}10^{-9}\) \\ \hline \end{tabular} Notes: \(I_{1}\): liquidity index (-), \(I_{0}\): density index (-), \(\rho\): bulk density of soil (g/cm\({}^{3}\)), \(k\): coefficient of permeability (m/s).  
\end{table}
Table 1: Main geotechnical characteristics of the subsoil.  
\begin{table}
\begin{tabular}{c c c} \hline
**Parameter** & **Unit** & **Value** \\ \hline \multicolumn{3}{c}{**Geometric Parameters**} \\ Thickness & m & 0.6 \\ Length & m & 1687.2 \\ Minimum depth & m & 3.0 \\ Mean depth & m & 8.6 \\ Maximum depth & m & 22.0 \\ Lateral surface area & m\({}^{2}\) & 14529.8 \\ \hline \multicolumn{3}{c}{**Filtration Parameters**} \\ Permeability coefficient after 28 days & m/s & \(2.5\times 10^{-8}\) \\ Permeability coefficient after 60 days & m/s & \(1.0\times 10^{-9}\) \\ \hline \multicolumn{3}{c}{**Strength Parameters**} \\ Compressive strength after 28 days & MPa & min. 0.53 \\ Compressive strength after 60 days & MPa & min. 0.91 \\ \hline \end{tabular}
\end{table}
Table 2: Characteristics of the vertical barrier.  
landfill site in order to control groundwater quality (Figure 2). Moreover, three sampling points were selected along the Lipkowska Woda watercourse to monitor surface water quality.  
Leachates were monitored in three sampling points in order to examine the amount of generated leachate and its quality. Fifteen indicators of pollution were examined for the leachates, surface water and groundwater.  
Quality tests were carried out focusing on the following indicators: electrical conductivity (EC), pH, lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), chromium (Cr), mercury (Hg), total organic carbon (TOC), polycyclic aromatic hydrocarbons (PAH), ammonium (NH4+), chemical oxygen demand (COD), biochemical oxygen demand (BOD), chlorides and sulfates.  
Moreover, continuous measurements of the precipitation and groundwater level were carried out as part of monitoring program for the landfill. The average value of a rainfall for analyzed area is 550 mm. Groundwater level in all piezometers shows seasonal pattern resulting from precipitation. It is also observed that due to the high groundwater level, lower concentration of pollution indicators is noted and conversely. Therefore, the physicochemical analyses of the groundwater samples can be coupled with measurements of groundwater level changes in piezometers.  
Figure 2: Location of the groundwater monitoring network in the study area.  
The monitoring network of the Radiowo landfill consists of: piezometer P-2A located on the outflow, to the east of the landfill; piezometers P-4 and P-6 located on the inflow (background), to the southeast of the landfill; piezometers P-7A, P-9, P-10A, P-11A, P-12 and P-17 located in the outflow; piezometers P-14A and P-15 located in the outflow, to the north from the composting area; and deep well S-1 located in the compostory plant area. Monitoring studies are conducted quarterly and annual reports are submitted to the administrative bodies responsible for the environment-related issues.