Термоелектране у Србији–утицај летећег пепела на земљиште и биљке
Thermal power plants in Serbia – the impact of ash on soil and plants
2013
Document Type:
Book part (Published version)
,
© Serbian Academy of Sciences and Arts
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Show full item recordAbstract:
Anthropogenically-caused disturbances, such as the formation of ash deposits as a result of the activities of thermal power plants, are processes which significantly alter the biodiversity of an area on varying temporal and spatial scales and all ecological levels. These processes lead to the loss of fertile soil; pollution of vegetation, soil and air; the uncontrolled introduction of allochthonous species; and erosion. The processes of anthropogenically-induced degradation reduce the quality of the habitat considerably, cause disturbances in the functioning of plants, as well as entire ecosystems, and set new demands in approaches to their restoration.
Rarely in nature are plants exposed to the effects of just one stress factor; instead, exposure to multiple, complex effects is most common. In conditions at ash deposit sites, plants are continuously and simultaneously affected by the unfavourable physical and chemical properties of ash (increased salinity and alkalinity, B, As and Mo toxicity, and an N, P, K, Cu, Mn and Zn deficit) and extreme microclimatic conditions (drought and high temperatures). Such conditions limit the survival and development of vegetation at the ash deposits as they threaten the usual course of the physiological processes in plants (transpiration and photosynthesis) and with it, normal leafing, flowering and fruiting. It is frequently the case that the physiological activity of plants decreases prior to the appearance of visible damage symptoms.
Despite the chronic and synergistic effects of stress factors, there are various plant species at the ash deposit sites which tolerate these unfavourable habitat conditions, and, with varying degrees of effort, manage to survive
and spread across the ash. In this study, it is suggested favouring colonization
by autochthonous plant species which take root easily and can populate
the ash deposit site relatively quickly. The ecological potential of these
species matches the potential of the ash deposits and hence the plants do
not require any special management. Therefore, the best contenders for the
recolonisation of the ash should be sought from among those species which
have the following characteristics: plants which grow naturally in that area;
perennials; plants which have an extensive root system and the ability for
vegetative reproduction; plants which have nitrogen fixation ability (N-fixers);
plants which can tolerate high pH, salinity and toxic elements; plants
which are tolerant to extremely high temperatures and drought conditions.
In the process of biologically restoring this type of degraded area, it is vital
to bear in mind the existing ecological, vegetative and floristic potential of
the area in question, which abounds in a wealth of life forms and ecological
types of plants. Therefore, the spontaneous colonization of woody and herbaceous
vegetation clearly points to one of the most important forms of activities
aimed at stabilising the ash, with a minimum financial outlay. Aside
from selecting the species, thought should also be given to when they are
sown and planted, so as a cover that is functional all year round is formed.
In addition, attention must be paid to the fact that different particle sizes
of ash can be found at the ash ponds (from the coarsest particles on the embankments
to the finest in the central areas), and this should be carefully
considered when selecting the species which would be sown/planted on the
embankments or in the central areas of the ash pond. The initial vegetative
cover must also absorb nutrients effectively so as to prevent their being
leached away into the deeper layers of ash and return them through decomposition,
hence creating the conditions for the formation of the precursor
to soil (humus). In this way, the conditions will be created for establishing
stable plant communities.
When the biological restoration of these sorts of areas is being considered,
rather than talk about standards and regulations, it is far more worthwhile
to reflect on experiences gained in recultivation, taking heed of the geographic
and climatic circumstances, in order to allow for possible interpolation
in concrete cases. Restoration strategies must be based on a sound
knowledge of the characteristics of fly (mixture of boiler and fly ash) and
bottom ash, of the deposition process and the characteristics of the ash deposit
(technical specifications). In addition, it is important to know that the
chemical characteristics of ash change over time, creating more favourable
conditions for plant growth. Becoming acquainted with the conditions mentioned
above and testing a large number of different plant species will allow
vegetation cover to be quickly established, and the species selected for this
purpose will bind the mobile substrate, as ash is, effectively, and reduce the
unfavourable effects on the environment and human health. In addition, and no less importantly, this will result in a strategy for the long-term, sustainable management of ash deposits during the lifespan of thermal power plants.
The permanent biological restoration of ash deposits is only possible once the thermal power plant has ceased operating as the periodic sluicing of ash into ash ponds which were inactive and which have already been colonised by plants destroys the long-term succession of vegetation. A biologically empty area forms once again and the process of revegetation restarts from the beginning.
Keywords:
Pepeo; Deponije pepela; Kontaminacija; Zemljište; Toksičnost; Stres; Adaptacije; Biljka; Biološko obnavljanjeFunding / projects:
- Ecophysiological adaptive strategies of plants in conditions of multiple stress (RS-MESTD-Basic Research (BR or ON)-173018)
In:
- Анђелковић М. Енергетика и животна средина. Belgrade: SASA; 2013. 403-31. (Научни скупови / Српска академија наука и уметности; књ. 43; Одељење хемијских и биолошких наука; књ. 4)