## 3 Results  
Initial Leachate Composition and the Impact of Reactor Design and Freezing Mode on Element Concentration in the Remaining Fluid  
There were significant differences in element concentrations in the initial leachate of frozen and thawed peat horizons, as well as between the peat of NE European tundra (BZT) and Western Siberia (WSL). Thus, the leachates of peat from the NE European Tundra demonstrated sizably lower pH than those of the WSL (4.74 and 5.8-6.2, respectively), with a 2.5 times higher DOC concentration (Table 1). As a result of such high acidity of organic-rich waters, the leachates of BZT peat were sizably, by a factor of 2 to 3, richer in Fe, Al, and other trace metals compared to those \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**Element**} & \multirow{2}{*}{**Western Siberian Lowland**} & \multicolumn{2}{c}{**European**} & \multirow{2}{*}{**Element**} & \multirow{2}{*}{**Western Siberian Lowland**} & \multirow{2}{*}{**European**} \\  & & & & & & & \\ \cline{2-2} \cline{6-8}  & **WSL** & & & & & & \\ \hline S.C, \(\mu\)S cm\({}^{-1}\) & 10 & 20 & 15.5 & Zr, \(\mu\)g/L & 0.0192 & 0.0878 & 0.4806 \\ UV24s, nm & 0.386 & 0.167 & 1.037 & Nb, \(\mu\)g/L & 0.0015 & 0.0007 & 0.0095 \\ pH & 5.78 & 6.2 & 4.74 & Mo, \(\mu\)g/L & 0.1083 & 0.9193 & 0.034 \\ DOC, mg/L & 9.1 & 8.0 & 27.4 & Cd, \(\mu\)g/L & 0.0607 & 0.0579 & 0.0045 \\ Li, \(\mu\)g/L & 0.01 & 0.01 & NA & Sb, \(\mu\)g/L & 0.0144 & 0.0566 & 0.007 \\ B, \(\mu\)g/L & 59.2 & 54.8 & 72.3 & Cs, \(\mu\)g/L & 0.0004 & 0.0004 & 0.0015 \\ Na, \(\mu\)g/L & 915 & 686 & 1472 & Ba, \(\mu\)g/L & 163.8 & 10.56 & 245 \\ Mg, \(\mu\)g/L & 73 & 8 & 150.3 & La, \(\mu\)g/L & 0.0214 & 0.0137 & 0.0375 \\ Al, \(\mu\)g/L & 15.6 & 9.8 & 78.1 & Ce, \(\mu\)g/L & 0.032 & 0.0277 & 0.069 \\ Si, \(\mu\)g/L & 32 & 19 & 388 & Pr, \(\mu\)g/L & 0.0031 & 0.0024 & 0.0084 \\ P, \(\mu\)g/L & 9.2 & 15.0 & 68.3 & Nd, \(\mu\)g/L & 0.0141 & 0.0096 & 0.0362 \\ K, \(\mu\)g/L & 215 & 113.3 & 732.5 & Sm, \(\mu\)g/L & 0.0049 & 0.0017 & 0.0101 \\ Ca, \(\mu\)g/L & 289 & 257.3 & 571.7 & Eu, \(\mu\)g/L & 0.0119 & 0.0011 & 0.0192 \\ Ti, \(\mu\)g/L & 0.106 & 0.1155 & 0.439 & Gd, \(\mu\)g/L & 0.0054 & 0.0031 & 0.0147 \\ V, \(\mu\)g/L & 0.360 & 0.2248 & 0.176 & Tb, \(\mu\)g/L & 0.0005 & 0.0003 & 0.0017 \\ Cr, \(\mu\)g/L & 0.040 & 0.06 & 0.460 & Dy, \(\mu\)g/L & 0.004 & 0.0023 & 0.0095 \\ Mn, \(\mu\)g/L & 1.26 & 0.1153 & 0.0323 & Ho, \(\mu\)g/L & 0.0007 & 0.0003 & 0.0017 \\ Fe, \(\mu\)g/L & 22.9 & 12.3 & 56.0 & Er, \(\mu\)g/L & 0.0068 & 0.0047 & 0.0058 \\ Co, \(\mu\)g/L & 0.015 & 0.0104 & 0.0373 & Tm, \(\mu\)g/L & 0.0005 & 0.0001 & 0.0009 \\ Ni, \(\mu\)g/L & 0.17 & 0.18 & 0.26 & Yb, \(\mu\)g/L & 0.0024 & 0.0009 & 0.0059 \\ Cu, \(\mu\)g/L & 0.674 & 0.7167 & 25.4 & Lu, \(\mu\)g/L & 0.0003 & 0.0002 & 0.0008 \\ Zn, \(\mu\)g/L & 212 & 8.62 & 420 & Hf, \(\mu\)g/L & 0.0019 & 0.0089 & 0.0343 \\ Ga, \(\mu\)g/L & 0.0002 & 0.0006 & 0.0181 & W, \(\mu\)g/L & 0.0069 & 0.0558 & 0.005 \\ As, \(\mu\)g/L & 0.1754 & 0.1352 & 0.2781 & Pb, \(\mu\)g/L & 0.044 & 0.025 & 1.406 \\ Rb, \(\mu\)g/L & 0.08 & 0.05 & 0.26 & Th, \(\mu\)g/L & 0.0019 & 0.0017 & 0.0204 \\ Sr, \(\mu\)g/L & 4.96 & 2.417 & 5.048 & U, \(\mu\)g/L & 0.0013 & 0.003 & 0.0074 \\ Y, \(\mu\)g/L & 0.0248 & 0.0114 & 0.0514 & & & & \\ \hline \hline \end{tabular} Note: S.C.—specific conductivity.  
\end{table} 
Table 1: Element concentrations in the initial leachates (<0.45 \(\upmu\)m) of frozen peat from NE European tundra (BZT) and frozen and thawed peat horizons of Western Siberia (F WSL and WSL, respectively). from the WSL peat. The leachates from the active horizon of the WSL peat layer exhibited 0.4 unit lower pH values, 1.5 to 2.0 times higher concentrations of Si, K, Fe, Al, Sr, and 10-20 times higher Mn, Zn, and Ba levels than the leachates from the frozen peat horizons.