Migration of Heavy Metals from Polluted Soil to Plants and Lichens under Conditions of Field Experiment on the Kola Peninsula
I. V. Lyanguzova, M. S. Bondarenko, A. I. Belyaeva, M. N. Kataeva, V. Sh. Barkan, A. Yu. Lyanguzov
Abstract
We have carried out a field experiment to study the migration of Ni, Cu, and Co from the organic horizon of Al–Fe-humus podzols polluted with heavy metals (HMs) to the dominant species of dwarf shrubs, mosses, and lichens forming the ground vegetation layer in middle-aged pine forests. The following hypotheses were tested: (1) the introduction of metallurgical dust causes destruction of ground vegetation layer even in the absence of sulfur dioxide; (2) the destruction of this layer is caused by high concentrations of HMs in the aboveground organs of plants and lichens, which lead to their death; and (3) the level of HM accumulation by different taxa is directly correlated with their strategy of mineral nutrition. The contents of Ni, Cu, and Co in the organic horizon of podzols and in the assimilatory organs of dominant dwarf shrub, moss, and lichen species were determined by atomic absorption spectrometry. High inter- and intracenotic variation in the level of HM pollution of the soil organic horizon was revealed, which caused spatially uneven destruction of the ground vegetation layer. The translocation of HMs from the polluted soil to the aboveground parts of plants and lichens leads to a 1.5- to 5-fold increase in the content of HMs in all species, which does not exceed the toxicity threshold and does not prevent their growth in the experimental plots. The introduction of metallurgical dust over 5 years made the level of pollution of the organic soil horizon comparable to that in the buffer zone of the Severonikel Plant. This made it possible to compare the HM content in plants and lichens under the conditions of soil and aerotechnogenic pollution and determine the features of HM accumulation by organisms with different strategies of mineral nutrition. The Ni < Cu concentration ratio in the organic soil horizon is reversed in the leaves of dwarf shrubs and green and brown parts of moss Pleurozium schreberi under conditions of either soil pollution and aerotechnogenic pollution.