Dimitar Antonov

Verified

Dimitar verified their affiliation via an institutional email.

Learn more

Verified

Dimitar verified their affiliation via an institutional email.

Learn more

• Doctor of Philosophy
• Professor (Associate) at Bulgarian Academy of Sciences

A specific type of landfill, a tailings dam (or pond), is typically an earth-fill embankment dam used to store the byproducts of mining operations after the ore has been separated from the gangue. The primary threat posed by a tailings pond is the potential for leachate generated by the slurry to penetrate the soil and contaminate the aquifer. Base...

Radon as a daughter product from the radioactive uranium family, is present in all rocks and soils in the geosphere. Its half-life (3.82 d) allows the element to migrate from the terrestrial environment to the surface. This migration can be intensified through preferential degassing pathways, such as faults or fracture systems Geogenic radon potent...

Indoor radon exposure is recognized as a significant cause of lung cancer, as shown by various epidemiological studies. One possible pathway for radon transport is through faults, where radon can escape into fractures and open spaces in rocks. Numerous studies link fault systems to elevated radon levels at the surface or within buildings. In Bulgar...

Loess from the Danubian Plain (Bulgaria) was used as the raw material for the solid-state synthesis of ceramics.The mineral phase composition of the loess fraction used was determined by powder X-ray phase analysis, and the chemical composition by X-ray fluorescence analysis. The semi-quantitatively determined mineral phases are quartz, plagioclase...

Environmental spread of radon gas (222Rn) has been intensively investigated in the last few years due to its harmful effects on human health. A concept of radon index is used to characterize the geogenic radon potential of the terrain, as the latter gives the probability of the presence of radon gas concentration in a building, the genesis of which...

RELATION BETWEEN INDOOR RADON CONCENTRATIONS AND GEOGENIC RADON POTENTIAL Bistra K. Kunovska1*, Todor Y. Yordanov1, Desislava K. Djunakova1, Dimitar I. Antonov2, Sava N.Kolev2, Kremena G. Ivanova1, Aleksey D. Benderev2 1 National Centre of Radiobiology and Radiation Protection, 3 Georgi Sofyiiski, Str., 1606 Sofia, Bulgaria 2 Geological Institute,...

The study deals with the evaluation of the dynamic of the radon index in one pilot site based on second-time pilot investigations of the radon index in Bulgaria. In situ measurements of the radon concentration in soil gas, and soil permeability at three polygons: one over and two – close to fault zone have been performed in October 2020 and October...

Natural radon (222Rn) is a radioactive noble gas that occurs in every rock or soil due to the content of radium (226Ra), part of the 238U family, in the lithosphere. One of the indicators for evaluating the impact of radon on a certain area/terrain, including on the biota, is the so-called geogenic radon potential. Different types of rocks and soil...

The construction of a compacted and stabilized layer with local soil from the excavation, mixed with Portland cement, is a soil improvement technique widely applied in foundation works in collapsible loess ground in Bulgaria. Commonly, the role of that cement-modified layer is to replace a part of the collapsible ground, to increase the bearing cap...

The development of a methodology for the geogenic radon potential (GRP) mapping based on soil gas radon and soil gas permeability field measurements is among the main objectives in the determination of “radon priority areas” in Bulgaria. One of the key elements of the methodology is to define as accurately as possible, areas of risk for the presenc...

Natural radon (222Rn) is a radioactive noble gas that occurs in every rock or soil due to the content of radium (226Ra), part of the 238U family, in the lithosphere. Different types of rocks and soils possess different 226Ra content and different permeability. Radon has high mobility and is driven by diffusion and convection with the soil gas throu...

INTRODUCTION The radon gas relieved from ground could accumulate in the building and contribute to human exposure. Exposure to indoor radon and its decay products contributes half of the annual dose received by the public from all natural radioactive sources [1]. Radon is recognized as a carcinogenic agent by the WHO and is the second leading cause...

The study deals with pilot investigations of the radon index in Bulgaria. In situ measurements of the radon activity and soil permeability at 3 sites one over and two-close to fault zone have been performed. The results show that higher radon content is detected in the fault zone.

In Bulgaria, from the preliminary analyses performed for site selection of deep geological disposal of high-level waste (HLW) and spent fuel (SF), it was concluded that the most promising host rocks are the argillaceous sediments of the Sumer Formation (Lower Cretaceous), situated in the Western Fore-Balkan Mts. The present paper aims to compare th...

The presence of arsenic in the Ogosta River Valley's alluvial sediments is subject to historical contamination due to upstream located ore-factories, tailing ponds, and even industrial accidents from the past. In recent years, there have been several types of research focused on different aspects of the contaminated alluvial sediments in the floodp...

Radon (222Rn) is a natural gas produced by the radioactive decay of uranium-bearing rocks and soils in the Earth’s crust. Geology is one of the main factors controlling source and distribution of radon. Most rocks and soils possess small amount of uranium, but there are particular types of bedrocks and unconsolidated deposits characterized by highe...

Loess and loess-like sediments cover approximately 13% of the Bulgarian territory, mainly within the Danubian plain. From the Danube River to the Fore-Balkan, the loess soils form a loess complex where its depth varies from 50-60 meters in the north to few meters in the south, respectively. Widespread loess sediments possess a specific feature: the...

The study deals with unsaturated hydraulic model of the marls from Sumer Formation in connection with geological disposal of radioactive waste. The model profile of 400 m in depth from the surface was implemented in HYDRUS-1D code. Two simulation periods were chosen-1 000 and 10 000 years. In both simulations, the results showed that after 940 year...

The Repository for Radioactive Waste in Novi Han, Lozen Mountain (Bulgaria), dates from the early 1960s. In the present study, the complex geoenvironmental setting of the repository site was analysed from the viewpoint of assessment of potential radionuclide migration from the repository to the geosphere. Thus, components of the mass transport fiel...

As a result of historical mining activities, some layers in the Ogosta Valley`s floodplain sediments are highly enriched in arsenic (As). Reductive release of iron (Fe) and As in the floodplain soil could be expected under reducing conditions, which would lead to an increase of the more toxic As species in the soil pore water. Therefore, it is impo...

Loess and loess-like sediments cover approximately 11% of the Bulgarian territory mostly in northern part of the country. From the Danube River to the ForeBalkan, the loess soils together with paleosoils constitute a loess complex where its depth varies from 50– 60 meters in north to few meters in south, respectively. Generally, the unsaturated zon...

The widespread loess deposits with a typically deep unsaturated zone are a specific feature of Northern Bulgaria. The vadose zone thickness varies from 1–2 up to 40–50 m. The downward water flux occurs as a diffuse infiltration in depth. It is controlled and in the same time characterized by so-called “soil-water retention curve”, representing the...

The Ogosta Valley downstream the town of Chiprovtsi, NW Bulgaria, was subject to long-lasting contamination with arsenic and other toxic elements due to mining and ore-processing activities in the second half of the last century. Although the exploitation of lead-silver and iron ores was ceased in the end of the 90`s, the soil in particular section...

The Ogosta Valley downstream the town of Chiprovtsi, NW Bulgaria, was subject to long-lasting contamination with arsenic and other toxic elements due to mining and ore-processing activities in the second half of the last century. Although the exploitation of lead-silver and iron ores was ceased in the end of the 90`s, the soil in particular section...

The paper presents an algorithm for modeling the vertical water transport of arsenic (As) in contaminated river floodplain deposits using the software product HYDRUS-1D. A scenario of river flooding is prepared with sample data from a model plot in the Ogosta River valley, northwestern Bulgaria. Meteorological and hydrological data were also used f...

HYDRUS-1D. Представен е сценарий на речно заливане с примерни данни от изследван участък в долината на р. Огоста между с. Белимел и яз. "Огоста". Резултатите от симулациите показват значимата роля на речните разливи за постъпването на арсен от замърсените почвени пластове към подземните води. Ключови думи: HYDRUS-1D, разливи, подземни води, монитор...

Modelling of radionuclide transport in the geosphere is a key issue of the evaluation of safety of low- and intermediate-level radioactive waste (LILW) repositories. In Bulgaria, due to the operation of Kozloduy Nuclear Power Plant (NPP), a building of such facility is ongoing. The migration of 90Sr was evaluated by simulation of flow and chemical...

Geochemical studies of seasonally collected mine, stream and drinking waters, bottom sediments (mine and stream) and soil samples from all mining sections were carried out in order to assess the rates of pollution in the immediate proximity to underground mining facilities and related waste rock dumps. The determined concentrations of studied eleme...

The soil-cement cushion represents a compacted and stabilized layer of the soil base, built under the foundation, which is intended to replace a part of the collapsible layer, to increase the bearing capacity of the soil base and/or to play a role of engineering barrier against migration of harmful substances in the geoenvironment. The soil-cement...

This paper is devoted to the objective and progress of the activities undertaken in the frames of the project DFNI -E02/4. The aim of the project is to quantify water flow within the unsaturated zone of the loess complex, which is widespread in North Bulgaria. With respect to substantial variability of precipitation and evaporation, water fluxes ch...

The region of the Western Balkan is characterized by its complex geology and the presence of polymetallic ores. Iron and base metal (Pb-Ag) deposits are located in the upper valley of the Ogosta River near the town of Chiprovtsi. The local Fe-ores are rich in arsenic and copper, while the Pb-Ag ores contain much zinc and cadmium. The former mining...

The Repository for Radioactive Waste (RAW) Novi Han of the Russian “Radon” type was built in the middle of 60-es, last century, in the Lozen Mountain near Sofia. Unconditioned wastes from medicine, military sources and scientific research activities are stored in it. The repository site has not been selected after detailed geological, hydrogeologic...

The location of the National radioactive waste repository is in the vicinity of Kozloduy NPP (Radiana site). The area offers advantages from the viewpoint of the local population reaction, the hazards related to radioactive waste transport and the natural conditions. It is important that the loess soils can be easily stabilized with hydraulic binde...

The importance of the unsaturated zone as an integral part of the litho-sphere for water flow and solute transport modelling has long been recognized. The hydraulic properties of the variably saturated zone are often comprehen-sively described by means of the van Genuchten–Mualem model. This paper deals with an inverse modelling approach using the...

The paper considers the results from the investigations of a team of the geological institute of the Bulgarian academy of Sciences in the Batova river valley (Balchik municipality) related with the expansion of construction. The geomorphological and geological conditions in the valley are studied and an engineering geological zoning is performed. T...

In the framework of selecting a suitable site for final disposal of low- and intermediate level short-lived radioactive waste (LILW-SL) in Bulgaria, site characterization is ongoing at the Marichin Valog site, North-West Bulgaria. The site is characterized by a complex sequence of loess, clayey gravel, and clay layers, of which the first 30-40m are...

Chiprovtsi silver-lead and Martinovo iron mines represent the biggest mining area in Northwestern Bulgaria, which was operated till 1999. Their long-lived operation leads to proved pollution of the environment in the vicinity of the mines, especially water and soil. Seasonal monitoring of heavy metal (Cu, Zn, Cd and Pb) and metalloid (As and Sb) co...

Loess and loess-like sediments occupy 13% of Bulgarian territory. Their collapsibility predetermined by existence of a great volume of macropores and non-water resistant particle binding substances causes serious problems in the construction activities. To avoid this unfavorable property a lot of research work is being carried out concerning loess...

The loess terrains near “Kozloduy” NPP are among the prospective areas for the disposal of low and intermediate level radioactive waste. The analysis of the loess properties has shown two main problems: a loess collapsibility and water permeability. Using a soil-cement cushion under the repository foundation and a soil-cement backfill between the c...

Investigations have been carried out on the composition and structure of loess in the vicinity of the Kozloduy Nuclear Power Plant in connection with the long-term disposal of radioactive waste. The thickness of loess in the investigated region is in the range from 10 to 40 m. The loess grain-size composition is characterised by predominating silty...

In the framework of selecting a suitable site for final disposal for low- and intermediate level short-lived radioactive waste in Bulgaria, a determination of soil hydraulic properties of two potential sites was made. The investigated samples are from the vadoze zone of the unsaturated deep soil profiles, which are considered as a pathway of eventu...