Soil-water influences on trace elements and organic matter in Arctic

In this study, the impact of pH on leaching of elements from soils was tested. Samples were taken from Bayelva / Stuphalle, Svalbard in August 2018. Overall, the impact of three pH levels, 2, 7 and 10 was investigated in Svalbard soils. Leached elements namely, Cd, Co, Cr, Cu, Fe, Ni, S and Zn showed V-shaped leaching curves. The concentrations of Cd, Co, Ni, Cu, Zn, Fe, Al were higher in pH 2 leachates, while the concentrations of S and Cr, Hg, Pb, Se, U were greater in pH 10 leachates. The concentrations of Cd, Co, Cr, Ni, Cu, Zn, Fe and S were lowest in pH 7 leachates. Among, the concentrations of elements Cd, Co, Cr, Ni, Zn and Fe decreased with increasing pH from 2 to 7 and increased again from pH 7 to 10; only element Al decreased with increasing pH value from 2 to 10. Conversely, the elements Hg, Pb, Se and U increased with raising pH value. In addition to this, current burden of background pollution of inorganic pollutants (trace elements) in organic and mineral soils was also investigated. SOM contents were significantly higher in organic soils (47.33 ± 16.56%) compared to mineral soils (6.07 ± 4.76%). Conversely, pH value of organic soils (6.495 ± 0.66) were significantly lower than mineral soils (7.22 ± 1.15). The levels of 11 trace elements (Cd, Cr, Co, Cu, Hg, Ni, Pb, Rb, Se, U, Zn) and 11 macro/micro elements (Al, B, Ca, Fe, K, Mg, Mn, Na, P, Si, S) for samples from both organic soils and mineral soils were investigated. The concentrations of Cd, Hg, Pb, Se and Zn were significantly higher in organic soils, whereas concentrations of Cr, Cu, Ni and Rb were significantly higher in mineral soils. Additionally, SOM positively correlated with Cd, Hg, Ca, S, Si and negatively related with Al, Fe, Mn, Cr, Cu, Ni, Rb, Co, Na, Mg, K, B. Cd, Hg and S had strongly positive correlation with each other. Al, Fe, K and Co, Cr, Cu Ni, Rb had significantly positive association with each other.