## 3 Results and Discussion
### Surface Laaching
The computed data give an estimated amount of leaching of Ni as 2.8178 mg/m\({}^{2}\) per year. \[y=0.3522\ln(time)+0.7399 \tag{2}\] \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Metal** & **O\_P6** & **O\_P7** & **O\_P8A** & **A \(H_{W}L_{B}\) 23** & **A \(H_{W}L_{B}\) 17** & **A \(H_{W}L_{B}\) 18** & **T \(H_{W}L_{B}\) 11** & **T \(H_{W}L_{B}\) 09** \\ \hline As & 0.0807 & 0.0782 & 0.105 & 0.0276 & 0.0050 & \textless{}0.0014 & 0.0042 & 0.0090 \\ Cd & \textless{}0.004 & \textless{}0.004 & \textless{}0.004 & 0.0025 & 0.00035 & \textless{}0.00028 & \textless{}0.0003 & \textless{}0.0003 \\ Cr & \textless{}0.04 & \textless{}0.04 & \textless{}0.04 & 0.006 & 0.010 & 0.0091 & 0.0091 & 0.024 \\ Hg & \textless{}0.002 & \textless{}0.002 & \textless{}0.002 & \textless{}0.0063 & \textless{}0.0070 & \textless{}0.0076 & \textless{}0.0082 \\ Ni & 0.272 & 0.411 & 0.4 & 0.52 & 1.1 & 0.14 & 0.46 & 0.69 \\ Zn & \textless{}0.2 & \textless{}0.2 & \textless{}0.2 & \textless{}0.013 & \textless{}0.014 & \textless{}0.014 & \textless{}0.015 & \textless{}0.02 \\ TBT & \(101\times 10^{-6}\) & \(103\times 10^{-6}\) & \(157\times 10^{-6}\) & \(275\times 10^{-6}\) & \(1180\times 10^{-6}\) & \textless{}15\times 10^{-6}\) & – & – \\ \hline \hline \end{tabular} Notations for Table 7: \(H_{W}L_{B}\) indicate a “high water/low binder” ratio in a mixture. The abbreviations indicate the locations where measurements were performed: Oslo (O), Arendal (A), and Timra (T).  
\end{table} 
Table 7: Surface leaching of contaminants (heavy metals and TBT, mg/m\({}^{2}\)) from soil after 9 days. Figure 5: Cumulative leaching of arsenic (As) against time in tested specimen samples. Figure 7 shows a graph of the cumulative leaching of PAH-16 in soil samples over time. Here, the results vary a little between sample 8A and samples 6 and 7. However, the standard deviation between those samples is low. The average value of the three samples is used to visualise a statistical trend line. The equation from this line is then used to calculate the expected leaching of PAH-16 after 365 days in m\({}^{2}\), according to Equation (3). This gives an estimated value of possible leaching of total PAH-16 as 0.0507 mg/m\({}^{2}\) from the soil in Kongshavn per one calendar year. \[y=0.0074\ln(time)+0.0071 \tag{3}\]  
The actual content of the PAH-16 substance reflects the results of the statistical analysis. The location of sampling marks was identified with each sampling case representing a central point of the line in a given transect. The detection limit was determined with regard to the standard deviation (Figure 7) obtained when evaluating soil samples. Leaching of PAH-16 is determined as 10 times the standard deviation for specimens and is roughly three times higher than the detected limits of PAH-16 presented in specimens. The dynamics of the PAH-16 leaching was detected based on the frequent measurements as regular samplings of the soil, represented on the lines of the graphs as dots encountered once for the period of measurements on each line segment. The lowest concentration level of PAH-16 was determined as a limit of quantification, that is, quantitatively assessed with a satisfactory certainty. The overall trend of PAH-16 leaching is increasing with regard to the line path, i.e., the total amount of contaminant is gradually released from the specimens along with soil treatment. This proves a positive effect of solidification and stabilization of soil on the removal of PAH-16 contaminants from soil. The leaching of PCB was not calculated since the values for leached amount of PCBs are positive, i.e., lower than the threshold limit. Figure 8 shows the dynamics of the cumulative leaching of organotin compound tributyltin (TBT) over time. Using the regression equation from Figure 8 extrapolated for a time period 365 days, the TBT leaching was modelled for a year in m\({}^{2}\), following Equation (4). The obtained results give an estimated amount of leaching of TBT of 0.00061 mg/m\({}^{2}\) per year.