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Weathering on Kamchatka volcanoes

Table 4. Differences in leaching factors for a big role, inasmuch as organic acids were used in the
elements from Tolbachik scoria experiments, which differ greatly in their complexing

Element LC (ox)/LC (ac) ability. Perhaps the bulk of the elements of the third
Group 1 group is present in the scoria as microscopic grains
of mineral phases that are poorly soluble in a slightly
Ca 1 0.71 acidic medium. The fourth group includes lead and
Mo ≈ 4 zinc, specifically. Their LC(ac) is several times higher
Cr 2.62 than LC(ox), that is, extraction with acetic acid is more
Cu 2.31 effective. This may be attributed to the good solubility
Na 2.92 of lead and zinc acetates.
Ni 3.69 6. Conclusion
Sr 3.13
Li 3.70 The present study has shown that biochemical
K 4.69 weathering for some important metals is significantly
Ba 3.47 more effective in the presence of oxalic acid. Earlier
Al 5.87 biochemical expeditions have shown that oxalic acid
Si 5.42 salts (oxalates) are present under lichens on the slag
cones of the Tolbachik volcano. New lichen species
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Group 2 have been discovered that are capable of producing
Co 10.96 oxalates in large quantities in the soil. Acetic acid is
Fe 48.77 released by more evolved higher plants – grass and
Mg 9.90 bush. Due to the organic ligands, the leaching factors of
Mn 6.66 the main water contaminants increase very significantly
Ti 16.74 (relative pure water leaching): Cu – 133 (57), Fe –
304 (6), Al – 526 (90), Mn – 115 (17), Pb – 2 (14), and
V 128.92 Zn – 2 (12), for oxalic (acetic) acid salts.
Group 3 Based on the analysis of crystal morphology, it was
Cd ≈ 1 concluded that the growth of crystals alternates with
Zr ≈ 1 their dissolution in the process of biomineralization.
B ≈ 1 Lichens are widespread on the Kamchatka Peninsula and
Group 4 are among the first living organisms to grow on volcanic
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Pb 0.15 formations. The predominant group is crustose
lichens, which are well known for colonizing stony
Zn 0.18 substrates of various chemical compositions. Due to
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their active metabolism, lichens interact with bedrock
acid, we infer that micro-grains of Fe(III) and Mn(IV) minerals, which leads to extensive oxalate formation.
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oxyhydroxides, which may be present in the samples, are On the basis of obtained results, we attributed the spikes
reduced in its presence to divalent iron and manganese of heavy metal concentrations in the Kamchatka river
compounds that are highly soluble in an acidic medium. during the 2015 – 2016 period to the leaching of fresh
Since vanadium, cobalt, and titanium are well adsorbed Tolbachik’ (TFE 2012 – 2013) eruption products.
by Fe(III) and Mn(IV) oxyhydroxides, we infer that From Group 2, cobalt (Co) and its compounds are
the reduction of the latter will be accompanied by a most toxic for human when ingested in high doses. Its
transition to the dissolved state of the adsorbed metals, inorganic compounds are known to have carcinogenic
as observed in our experiments. and mutagenic effects, too. For example, sulfate CoSO
4
The third group, including cadmium, zirconium, and octacarbonyl cobalt vapors Co (CO) are especially
8
2
and boron, is characterized by weak and approximately toxic. The toxic lethal dose (LD50 for rats) is 50 mg.
identical extraction values. The reason that the elements The MPC of cobalt dust in the air is 0.5 mg/m , whereas
3
of this group do not have noticeable differences in in drinking water, the MPC of cobalt salts is 0.1 mg/L.
the mobilization by different acids is not clear. The Meanwhile, the quality of water for the protection of
processes of complexation in this case should not play aquatic life is subject to stricter requirements: MPC
Co

Volume 22 Issue 1 (2025) 39 doi: 10.36922/ajwep.8113