## 3 Results and Discussion
### Concentrations of Contaminants  
The detailed chemical information was obtained as concentrations of pollutants in the leachate of soil samples evaluating the leaching mechanism of the contaminants. The obtained results with full data are summarised in Tables and presented in the Appendix of this study. The Appendix A contains the results of leaching of contaminants in sampling passes 2317-2324; Appendix B presents the results of leaching of contaminants in sampling passes 2325-2332, and Appendix C summarises the results of leaching of contaminants in sampling passes 2333-2340. The background (original) levels of the concentration of contaminants were evaluated and presented in Table 3. The analysis of the original level of contaminants enabled to perform the evaluation of the decontamination of soil based on the discriminating the actual values of pollutants against those of the original (background) level. In such a way, the degree of concentration of contaminants in soil samples was evaluated using the analysis of leaching dynamics for each contaminant, respectively. Reading these data obtained from the leaching experiments include the analysis of information on the amount and concentration of the resolved pollutants with respect to the overall amount of soil and, thus, to evaluate the obtained level of contamination to prevent ecological risks. The evaluated substances included seven (7) types of heavy metals (mg/kg), total PAH-16 (mg/kg) and Tributyltin-Sn (TBT) (ug Sn/kg), as shown in Table 3.  
Figure 4: Permeability of soil samples changing over time of experiment (in hours), Specim IDs: (a) 1_5, (b) 4_1, (c) 5_4, (d) 3_5, (e) 6_5, and (f) 8_5. The most important parameters in the context of soil contamination by heavy metals have been assessed for the following metal types, arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), zinc (Zn), as shown in Table 3. The tests also evaluating the concentrations of elements in soil samples were tested for the organic compounds--16 priority Polycyclic Aromatic Hydrocarbon (PAH) and organotin compounds Tributylutin (TBT), Table 3, and for organic chemicals Polychlorinated biphenyl (PCB) (7 pcs), Table 4. The hydraulic conductivity evaluated the leachate percolation through the soil monolith, and reported in the Appendix in Table 1 showing 251-275 uS for samplings 2317-2324, Table 3 showing 253-274 uS for samplings 2325-2332, and in Table 5 showing 252-276 uS for sampling 2333-2340. Thus, in all cases the conductivity slightly increases in course of the experiment from 6 h to 64 days. The withdrawal of water for analysis of surface leaching was performed with the following intervals of time periods after 6h of testing, 1 d (24 h), 2.25 days (54 h), and then on days 4, 9, 16, 36, and 64. The repetitions of the tests arranged periodically with a non-linear time gaps in the laboratory across the soil samples enabled to indicate the marks of leaching levels of each of the contaminants separating the amounts of the leached substances from the soil samples. The analysis demonstrated the following leaching values (mg/m\({}^{2}\)): the highest values of As reached 0.88 with average 0.71; the highest values of Ni reached 2.48 with average 2.20; the maximal leaching of PAH-16 is 0.053 with average 0.039; and the leaching of TBT increased to 0.0010 with average of 0.0009, respectively. In order to make a comparison of the contamination level in current state against the pre-industrial conditions, the deviation classification for heavy metals in sediments has been carried out according to the existing Swedish standards [93]. The table is recalculated using values from tables 34 and 36 in the Swedish Environmental Protection Agency's report 4914 (mg/kg TS).