The relevance of the research topic is determined by the increasing role of natural reservoirs and their vegetation in the processes of self-purification of ecosystems against the background of increasing pollution of natural environments. Due to the constant anthropogenic impact especially near landfills, many toxicants including heavy metals enter the environment. They cannot be removed either by chemical or biological transformation due to their resistance to the environment and lack of the possibility of decomposition. However, there are ways to remove them from the soil and water. Research shows that plants have the ability to accumulate heavy metals in themselves. This allows developing methods using plants to clean the soil from heavy metals. At present, the accumulative abilities of vegetation in the North-West of Russia with respect to heavy metals are poorly studied, including for coastal-aquatic vegetation, which is actively used in the more southern regions.
Heavy metals are one of the most dangerous environmental pollutants. Arsenic, cadmium, mercury, lead, selenium, and zinc (As, Cd, Hg, Pb, Se, and Zn) are included in the list of particularly toxic metals. It is proved that after certain chemical reactions, these elements are distributed in the atmosphere, hydrosphere, and lithosphere of the Earth.
It is known that a large amount of heavy metals is concentrated in the soil. Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent, they enter our body through food, drinking water and air. As trace elements, some heavy metals (for example, copper, selenium, zinc) are necessary to maintain the metabolism of the human body. However, at higher concentrations, they can lead to poisoning. Heavy metal poisoning can be caused, for example, by contamination of drinking water (for example, lead pipes), high concentrations in the atmospheric air near sources of emissions, or through the food chain.Research accumulative ability of coastal aquatic plants held on two shallow waters of the Leningrad Region, with similar geographical, hydrological, and microclimatic features. At the same time, one of the reservoirs can be characterized as uncontaminated by heavy metals – Bolshoe Rakovoe Lake in the reserve "Rakovye Lakes", the other one – an artificial shallow reservoir formed on the site of an extensive peat processing zone – has a constant source of industrial pollution, including heavy metals, from the municipal solid waste landfill "Severnaya Samarka", directly adjacent to the water body. Both studied reservoirs have almost complete overgrowth of the surface with communities of aquatic and coastal plants and are in the stage of active overgrowth over the entire area.
The main results of the study are the obtained data on the content of heavy metals in coastal and aquatic plants and the factors affecting it, as well as information on the accumulative activity of the examined plant species in the conditions of undisturbed shallow ecosystem of the lake, and in the conditions of pronounced pollution of bottom sediments of heavy metals from the landfill.
Different ecological groups of plants differ somewhat in their ability to extract certain heavy metals from the soil. Studies have shown that heavy metals are better accumulated by submerged plants and vegetation of the edge of the floats. However, it is possible to distinguish individual species that within their ecological group showed greater importance in terms of accumulation – marsh whitefly and common reed.
The obtained results indicate the ecochemical aspect of the importance of preserving the plant species diversity of ecosystems under the influence of industrial facilities, particularly, such as landfills. Also, the scientifically based use of the difference between the bioaccumulative capabilities of plants and the properties of certain plant species can increase the effectiveness of protective zones around landfills, as well as allow the formation of a database of plants that can accumulate relatively large concentrations of heavy metals, which will accelerate the development of technologies for cleaning polluted environments using phytoremediation in the North-West Region of Russia.
|Position of speaker||PhD student|
|Publication||IOP Conference Series: Earth and Environmental Science|
|Affiliation of speaker||ITMO University|