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Introduction
Modelling the spatial distribution of arsenic and heavy metal concentration in the soil of river floodplains using GLM, machine learning techniques and MaxEnt.
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Publications (67)
This study aims to reveal the arsenic dynamics in groundwater of а river floodplain contaminated with mine tailings under temperate climate conditions and natural river hydrodynamics. Arsenic concentrations were monitored in the primary morphological units of the floodplain in the upper stretch of the Ogosta River in NW Bulgaria. Iron, lead-silver,...
The present study aims to determine the spatial distribution of soils with lead (Pb) content above the quality thresholds in a section of the Ogosta River valley (NW Bulgaria). The study area was contaminated with mine waste from the extraction and flotation of iron, lead-silver, and gold-bearing ores in the second half of the XX century. Predictiv...
The study aimed to identify land cover and land use transformations in the Lom River valley to reveal how the pressure of agriculture on the environment in the southwestern part of the Lower Danube basin has changed over the last 60 years. The classes at the fourth level of the CORINE Land Cover nomenclature were mapped using aerial photographs of...
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...
The current research aims to present land cover changes for the period 1993-2019 in the arsenic-contaminated Ogosta River valley in the context of the contaminant dispersal in the soils of the river floodplain caused by the agricultural practices and land use. The investigation is conducted for two test sites situated in the upper and lower stretch...
Floodplains are complex systems which include a wide number of socio-economic activities like agriculture, freshwater fisheries, electricity from power plants and others. They have often highly dynamic property, due to the alternation of fluvial processes, floods, and ongoing sediment transport, as well as of environmental specifics and natural or...
In this paper, we assess the hazard of heavy metal pollution of soil in the Tsibarska Lowland (Bulgaria) in the case of inundation from the Danube. The assessment takes into account the following two parameters: a degree of heavy metal pollution of river sediment (Me) and topography (To). The elaborated map shows levels of hazard which are closely...
The monitoring system in the Ogosta River valley is specifically designed to investigate the dependence of spatial distribution of arsenic in groundwater on the environmental settings of a floodplain which is contaminated with sulphides from mine tailings. The location of 25 piezometers takes into consideration the geomorphological features of the...
The purpose of this study is to categorise 21 groundwater monitoring points in the mining-affected valley of the Ogosta River in Northwestern Bulgaria according to the conditions for arsenic contamination of the alluvial aquifer. The grouping of the sites has been performed based on geochemical and geographical indicators using cluster analysis. Re...
This paper presents a concept of an integrated geodatabase for surface water, soil and groundwater pollution with arsenic in the upper part of the Ogosta Valley (Northwestern Bulgaria) using ArcGIS™ (ESRI®) file geodatabase. A geodatabase model diagram is created to enable data storage and to meet research requirements ensuring clear geodatabase st...
This paper presents an actual and overall picture of soil contamination with copper in the Bulgarian part of the Danube floodplain between the rivers Timok and Vit. Three sampling campaigns in October 2012, April 2013, and October 2017 are carried out in the frame of two studies. The total content of copper is determined by atomic spectrometry in t...
The spatial distribution of 665 soil sampling sites in the arsenic contaminated floodplain of the Ogosta River in the Northwest of Bulgaria is analysed against geomorphological parameters computed from a precise digital terrain model. The study aims at partitioning and classifications of hidden patterns of the morphographic features of the river fl...
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...
The aim of the current research is to present an actual and overall picture of the arsenic
(As) contamination of the soils in the Bulgarian part of the Danube floodplain between
the Timok River and the Vit River including the following lowlands: Bregovo-
Novoselska, Vidinska, Archaro-Orsoiska, Dolnotsibarska, Kozloduyska, Ostrovska and
Chernopolska...
The aim of the current research is to present an actual and overall picture of the arsenic (As) contamination of the soils in the Bulgarian part of the Danube floodplain between the Timok River and the Vit River including the following lowlands: Bregovo-Novoselska, Vidinska, Archaro-Orsoiska, Dolnotsibarska, Kozloduyska, Ostrovska and Chernopolska....
The aim of the current research is to present an actual and overall picture of the arsenic (As) contamination of the soils in the Bulgarian part of the Danube floodplain between the Timok River and the Vit River including the following lowlands: Bregovo-Novoselska, Vidinska, Archaro-Orsoiska, Dolnotsibarska, Kozloduyska, Ostrovska and Chernopolska....
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...
An attempt is made to model numerically the transport of dissolved substances caused by a difference in groundwater densities. It is supposed that initially at the surface of the aquifer a sector exists with high concentration of а pollutant (sulphates) while it is zero elsewhere in it. As a result, there is a higher water density near the surface....
Mining activities have contaminated many riverine floodplains with arsenic (As). When floodplain soils become anoxic under water-saturated conditions, As can be released from the solid phase. Several microbially-driven As solubilization processes and numerous influential factors were recognized in the past. However, the interplay and relative impor...
In the recent years there has been a steady increase in the concentrations of arsenic in the Kobilyak karst spring. After a complex research, the Ogosta River was found to be the source of pollution, and the reason is the accelerated lateral and bottom erosion of the river, which relieves the infiltration of river waters into the karst limestones a...
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...
23. 09-25. 09. 2016 г. Abstract: The article provides an overview of the concepts and methods applied for evaluation of the risk for chemical contamination of groundwater and their consistency with the concept of ecological risk assessment. The aim of this study is selection of indicators for estimation of the specific risk for arsenic pollution of...
The article provides an overview of the concepts and methods applied for evaluation of the risk for chemical contamination of groundwater and their consistency with the concept of ecological risk assessment. The aim of this study is selection of indicators for estimation of the specific risk for arsenic pollution of groundwater in contaminated rive...
Riverine floodplains downstream of active or former metal sulfide mines are in many cases contaminated with trace metals and metalloids, including arsenic (As). Since decontamination of such floodplains on a large scale is unfeasible, management of contaminated land must focus on providing land use guidelines or even restrictions. This should be ba...
Arsenic (As) is a toxic element which can occur in increased concentrations mainly in areas affected by mining and ore processing activities. To assess the As fractionation in soils from the Ogosta River floodplain, a seven-step sequential extraction procedure (SEP) followed by As determination using ultrasonic nebulization inductively coupled plas...
The aim of this study is to evaluate the specific groundwater vulnerability of arsenic contamination in the specific environmental conditions of river floodplains. For this purpose DRESPI modification of DRASTIC index is elaborated and tested in the arsenic polluted Ogosta Valley, NW Bulgaria. The assessment takes into account the following six par...
The aim of this study is to evaluate the specific groundwater vulnerability of arsenic contamination in the specific environmental conditions of river floodplains. For this purpose DRESPI modification of DRASTIC index is elaborated and tested in the arsenic polluted Ogosta Valley, NW Bulgaria. The assessment takes into account the following six par...
The aim of this study is to evaluate the specific groundwater vulnerability of arsenic contamination in the specific environmental conditions of river floodplains. For this purpose DRESPI modification of DRASTIC index is elaborated and tested in the arsenic polluted Ogosta Valley, NW Bulgaria. The assessment takes into account the following six par...
Floodplain soils are frequently contaminated with metal(loid)s due to present or historic mining, but data on the bioaccessibility (BA) of contaminants in these periodically flooded soils are scarce. Therefore, we studied the speciation of As and Fe in eight As-contaminated circumneutral floodplain soils (≤21600 mg As/kg) and their size fractions u...
The aim of the current reserach is to present an actual and overall picture of the heavy metal contamination of the river channel and floodplain sediment in the lower stretches of the four biggest international rivers which flow into the North of the Aegean Sea. Two sampling campaignes were carried out in 2010 and 2014. Concentrations (ppm) of As,...
Arsenic is a toxic trace element, which commonly occurs as contaminant in riverine flood-plains and associated wetlands affected by mining and ore processing. In this study, we investigated the solid-phase speciation of As in river floodplain soils characterized by circumneutral pH (5.7-7.1) and As concentrations of up to 40.3 g/kg caused by former...
Magnetic and geochemical analyses on a collection of 84 soil samples from the alluvial plain of Ogosta river and its tributaries (NW Bulgaria) have been carried out for revealing the pollution pathways and the role of iron oxides in mobilization, vertical re-distribution and occurrence of different heavy metals in Fluvisols. Three depth soil profil...
The Chiprovtsi area is polluted with arsenic and heavy metals as consequence of past mining activity. Analysis of surface waters yielded a range of Pb concentrations from <2 to 6 µg/l, of Zn – from <2 to 56 µg/l, of Cu – from <1 to 6 µg/l. As-concentrations vary from under the detection limit to 437 µg/l. The sequential extraction procedure of stre...
Metal dispersal in the Danube and Maritsa drainage basins resulting from metal mining activities in Bulgaria has been assessed through the collection of 611 samples of river water, river channel and floodplain sediment, and mine waste from over 218 sites. Concentrations of Cd, Cu, Pb, and Zn in river water were found to be highest in close proximit...
Bulgaria occupies a unique position in south-east Europe in terms of river basin management and control because contamination from metal extraction and processing industries not only has a potential significant trans-border impact but also affects both the Mediterranean and Black Seas. However, to date, no whole basin source to sink study of metal...
Lead isotope signatures (207Pb/206Pb, 208Pb/206Pb, 208Pb/204Pb, 206Pb/204Pb), determined by magnetic sector ICP-MS in river channel sediment, metal ores and mine waste, have been used as geochemical tracers to quantify the delivery and dispersal of sediment-associated metals in the lower Danube River catchment. Due to a diverse geology and range of...
Metal dispersal in the Danube and Maritsa drainage basins resulting from metal mining activities in Bulgaria has been assessed
through the collection of 611 samples of river water, river channel and floodplain sediment, and mine waste from over 218
sites. Concentrations of Cd, Cu, Pb, and Zn in river water were found to be highest in close proximit...
In this study Pb isotope signatures were used to identify the provenance of contaminant metals and establish patterns of downstream sediment dispersal within the River Maritsa catchment, which is impacted by the mining of polymetallic ores. A two-fold modelling approach was undertaken to quantify sediment-associated metal delivery to the Maritsa ca...
The content of Pb, Cd, As, Cu, Zn in the river water (206 samples), the river bottom sediments (204 samples) and in the floodplain (180 samples) of the major river systems in the country have been surveyed in August 2004 in Northern Bulgaria, and in June 2005 in Southern Bulgaria. The maximum acceptable values for the III category surface waters an...
The Chiprovtsi mining area is contaminated as a consequence of past mining. The 20-year existing of Goliam Bukovets mine tailings impoundment has affected all elements of its surroundings. As a result elevated concentrations of arsenic and heavy metals in upper soil layers and in grass are established. The low distributions of arsenic and heavy met...
This article presents main results from the implementation of the KINEROS model to the Malki Iskar river basin above the town of Etropole. KINEROS is a mathematical model based on fundamental physical laws aimed at simulating the spatial distribution of water balance elements for a given meteoro-logical event. A detailed study of the set of physica...
This article presents main results from the implementation of the KINEROS model to the Malki Iskar river basin above the town of Etropole. KINEROS is a mathematical model based on fundamental physical laws aimed at simulating the spatial distribution of water balance elements for a given meteorological event. A detailed study of the set of physical...
Investigation on the copper (Cu), lead (Pb), cadmium (Cd), zink (Zn) and arsenic (As) concentrations in the Malki Iskar River bottom and floodplain sediments was conducted in 2004 at lower water stage and in 2005 at high flood levels. Higher heavy metal contents in the river sediments and intensive contaminant dispersal along the main river were ob...
Current paper represents partly the results of a complex investigation on Chiprovska River catchment area after ceasing the activity of ore-extracting enterprise “Chiprovets” Ltd. Concentration trends of the heavy metals Pb, Cu, Zn, Cd, as well as of the metalloid As have been exhibited on the head river and its basic tributaries. These appear to b...
The research aim to mirror the present situation of the forest and meadow landscapes in middle- and high mountain belts of the Middle Rhodopes (crests Mursalitsa and Chernatitsa). Some elements of landscape methods (such geomasses, geohorizons, vertical structure), develop by Nikoloz Beruchashvili, have been applied. This approach gives the possibi...
