Field experiments helped the geographers from Lomonosov Moscow State University to update the oil pollution threshold levels for plant communities of various types. New data have confirmed that mosses and marsh vegetation are the fastest to cope with the consequences of environmental disasters. At the same time, grasses and shrubs of mixed forests of European Russia are more vulnerable than the flora of the Far East.
The first stage of work, that is carried out as part of the project of the Russian Foundation for Basic Research, was the study of the consequences of kerosene getting into the soils of the Far Eastern taiga in Amur Oblast. In 2021, the specialists from the Faculty of Geography of Moscow State University revealed high resistance to negative impacts in mosses and successful restoration of the moss-lichen cover after one year, even with heavy pollution.
The problems of pollution of natural communities with petrochemicals are currently being actively studied by scientists from around the world. At the same time, diesel fuel, gasoline, kerosene and other refined products attract less attention from the scientific community, although they are much more toxic than crude oil. Kerosene is a fuel used in aviation and astronautics. Its leaks are often associated with the operation of airfields, fuel and lubricants depots, and rocket launches from spaceports. If accidents occur at these facilities, the impact on nature can be catastrophic.
In the spring of 2022, the MSU geographers completed a field experiment in Kaluga Oblast. Using 36 experimental sites as an example, they studied vegetation restoration when forest and meadow-marsh communities were contaminated with kerosene. The obtained data were compared with the results of studies in Amur Oblast.
“The vegetation of mixed forests of the European part of Russia turned out to be more vulnerable to petrochemical pollution compared to the vegetation of the Far East. At relatively low loads (1–5 grams of kerosene per kilogram of soil), a year later, at the experimental sites in Amur Oblast, the grass-shrub layer was restored almost in full. And in Kaluga Oblast, herbaceous plants that disappeared from the community did not recover even with minimal load,” said Tatyana Koroleva, project manager, head of the laboratory of the Faculty of Geography of Lomonosov Moscow State University.
It also turned out that swamp shrubs in Central Russia are much more resistant to kerosene pollution compared to forest vegetation. Even the highest load used in the experiment – 100 grams of petrochemicals per kilogram of soil – did not lead to the death of wild rosemary and leatherleaf specimens. The observed consequences were limited to chemical burns of a part of the leaves and the death of individual shoots. Cranberries endured catastrophic loads much worse. The introduction of any doses into the soil led to the death of all the leaves on the plants. However, with light influence (1–5 grams per kilogram), a month later, the shoots began to grow again.
“Mosses got the advantage in our experiment. In the raised bog in Kaluga Oblast, even the highest load did not cause degradation of the moss cover. A year later, the state of sphagnum mosses did not differ from the surrounding areas. In the forest, green mosses, widely represented at the experiment sites, felt more at ease in the absence of competition with herbaceous plants. Over the year, they have grown significantly, especially at the sites with medium loads (10–25 grams per kilogram),” said Sergey Lednev, a project participant, an employee at the Faculty of Geography of Lomonosov Moscow State University.
The introduction of kerosene at a load of 100 g/kg in the forest (left, 1–3) and marsh (right, 4–6) communities: 1, 4 – before the introduction of kerosene; 2, 5 – a month after the introduction of kerosene; 3, 6 – a year after the introduction of kerosene.
According to Ivan Semenkov, senior researcher at the Faculty of Geography of Lomonosov Moscow State University, the data obtained during a series of field experiments help to clarify the threshold levels of kerosene pollution of plant communities.
“The Far Eastern experiment showed that significant changes in the structure of communities after a year are recorded at the applied loads of kerosene in the range from 5 to 25 grams per kilogram. The current experiment in Kaluga Oblast allows to narrow this interval: 1–5 grams per kilogram for mixed forests and 5–10 grams per kilogram for raised bogs,” Semenkov added.
The results of the research by the geographers from Moscow State University can later be used to assess the risks of pollution during the construction of fuel and energy facilities and transport systems, as well as to determine environmental damage in case of accidents during which oil spills occur.