Attila Anton

Modelling the Potential Effects of the Hungarian Red Mud Disaster on Soil Properties

In this experiment, the effects of the Hungarian red mud disaster were studied in a soil column experiment focusing on element solubility. The effect of flooding with the highly alkaline red mud suspension and the effect of the percolation of precipitation water through the 10 cm thick red mud layer were modelled separately. Both scenarios affected the soil pH up to a depth of 80 cm. An increase in the total element concentration was only observed for Na and Mo, probably due to the leaching of red mud particles measuring 0.05–0.02 and <0.002 mm in the column. At the same time, the water-soluble concentrations of the potentially toxic elements As, Co, Cr, Cu, Ni, Pb, and Zn rose, at least in the top soil layer, but the concentration values remained below the limit values laid down by quality standards. Over a longer period of time, the main environmental risk raised by the disaster is the secondary salinization of the area.

Red Mud as a Chemical Stabilizer for Soil Contaminated with Toxic Metals

We performed a 2-year microcosm study to assess the effectiveness of red mud, a by-product of bauxite processing, in stabilizing contaminated mine waste and agricultural soil. Our study used red mud from a long-term disposal area in Almásfüzitő, Hungary with a pH of 9.0. A 5% (by weight) red mud addition decreased the highly mobile, water-extractable amount of Cd and Zn by 57% and 87%, respectively, in the agricultural soil and by 73% and 79%, respectively, in the mine waste. In a laboratory lysimeter study, the addition of red mud reduced the concentration of Cd and Zn in the leachate by about two third of the original. The metal content of the leachate was below the Maximum Effect Based Quality Criteria for surface water as determined by a risk assessment in the metal-contaminated area of the Toka valley near Gyöngyösoroszi, Hungary. The addition of red mud did not increase the toxicity of the treated mine waste and soil and decreased the Cd and Zn uptake of Sinapis alba test plants by 18–29%. These results indicate that red mud applied to agricultural soil has no negative effects on plants and soil microbes and decreases the amounts of mobile metals, thus indicating its value for soil remediation.

Effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the affected area. The chemical changes caused by the red mud leachate and the effects of these changes on living organisms were assessed. Ecotoxicological tests were performed with Vibrio fischeri, Sinapis alba and Folsomia candida and the number of aerobic heterotrophic microorganisms was determined. The total, plant-available, exchangeable and water-soluble fractions of Na, Mo, Cu and Cr increased in the soil, mostly owing to their leaching from the red mud layer, but partly to the increase in the pH and DOC concentration. The chemical changes only had significant effects on the test organisms in the 0–30 cm soil layer, except for F. candida, which also had a lower survival rate in the 30–50 cm soil layer. No severe toxic effects were detected in the test organisms; in fact a stimulating effect was revealed for the aerobic heterotrophic cell number and for S. alba germination. However, the red mud itself was toxic, so the ecotoxicological tests justified the removal of red mud from the soil surface after the disaster.

Environmental risk assessment of red mud contaminated land in Hungary

The red mud catastrophe of October 2010 in Hungary draw the attention to the problem of red mud disposal sites, storage reservoirs and other wastes of mining origin that pose severe threats to humans and the environment all over the world. Present study introduces the results of the risk assessment that supported management of the priority risks and decision making on the necessary and most efficient risk reduction measures.

Environmental Impact of Soil Pollution with Toxic Elements from the Lead And Zinc Mine at Gyöngyösoroszi (Hungary)

Toxic elements from the lead (Pb) and zinc (Zn) mine at Gyöngyösoroszi (Northeast Hungary) cause pollution and potential risk to the ecosystem and human health. The aim of this work was to determine the contamination level at two sites planted with willow (Salix sp. L.) and corn (Zea mays L.) along the Toka valley, to evaluate soil quality by biological and biochemical parameters, and to assess potential risk for human health. Total arsenic (As), cadmium (Cd), copper (Cu), Pb, Zn, and mercury (Hg) contents in polluted soils reached values up to 384, 28.8, 493, 2827, 4417, and 4.46 mg kg−1, respectively. Values of these elements in the polluted soil for willow were 3.7 to 31 times higher and in corn were 2.3 to 20.9 times higher than in the unpolluted soil. All measured parameters therefore indicated soil pollution. Plant emergence percentage and plant and microbial biomass decreased whereas water‐extractable organic carbon (C), phosphatase activity, and corn root infection by arbuscular mychorrizal AM fungi and toxic metal content of the tested plants increased significantly. The results showed a high soil pollution level and consequently a great potential risk for human health (value of the additive hazard quotient was 11.21) and indicated the necessity for remediation of the site.

Chemical Stabilisation Combined with Phytostabilisation Applied to Mine Waste Contaminated Soils in Hungary

Gyöngyösoroszi is an abandoned lead-zinc sulphide ore mining area in Hungary. The diffuse pollution sources of mining origin identified in the area and the residual pollution after removal of the point sources will be subjected to combined chemical- and phytostabilisation. To select the best chemical stabiliser laboratory scale experiments were performed in microcosms. The following chemical additives were tested in various concentrations: three different fly ashes, lignite, alginite, hydrated lime, raw phosphate, iron hydroxide wastes from drinking-water treatment, red mud and the mixture of selected ones. The stabilisation of toxic metals in the soil was monitored by an integrated methodology, which combined physico-chemical analysis with toxicity testing. Based on the chemical analytical and the bacterial and plant toxicity test results, one of the tested fly ash types was the most effective: the mobile Cd and Zn concentration decreased by 50–99% in the fly ash treated contaminated soil, the bacterial and plant toxicity decreased by 30-70%, and the bioaccumulated metal amount by 70%. The combination of lignite, alginite, lime and phosphate was also efficient.

Laboratory-scale evaluation of a combined soil amendment for the enhanced biodegradation of propylene glycol-based aircraft de-icing fluids.

A combined soil amendment was tested in microcosm experiments with an aim to enhance the aerobic biodegradation of propylene glycol (PG)-based aircraft de-icing fluids during and following the infiltration of contaminated snowmelt. A key objective under field conditions is to increase degradation of organic pollutants in the surface soil where higher microbial activity and plant rhizosphere effects may contribute to a more efficient biodegradation of PG, compared to subsoil ground layers, where electron acceptors and nutrients are often depleted. Microcosm experiments were set up in Petri dishes using 50 g of soil mixed with appropriate additives. The samples contained an initial de-icing fluid concentration of 10,000 mg/kg soil. A combined amendment using calcium peroxide, activated carbon and 1×Hoagland solution resulted in significantly higher degradation rates for PG both at 4 and 22°C. Most probable numbers of bacteria capable of utilizing 10,000 mg/kg de-icing fluid as a sole carbon source were about two orders of magnitude higher in the amended soil samples compared to unamended controls at both temperatures. The elevated numbers of such bacteria in surface soil may be a source of cells transported to the subsoil by snowmelt infiltration. The near-surface application of amendments tested here may enhance the growth of plants and plant roots in the contaminated area, as well as microbes to be found at greater depth, and hence increase the degradation of a contaminant plume present in the ground.

Effect of C-sources and urea on the available N-content and urease activity of a calcareous sandy soil

Summary In a model experiment the adding of urea to a calcareous sandy soil generally increased the available N-content of soil samples. This process is most characteristic in case of urea-treatment without C-sources. The application of C-sources together with urea decreased the rate of mineralization of organic N. Using of C-sources without N-source increased the rate of microbial immobilization of soil N. These conclusions were suggested by measuring microbial number and the urease activity as well.

Stabilization of Cr, Pb, and Zn in Soil Using Lignite

A uniform multivariable model system was used to investigate whether lignite from Visonta (Hungary) has a stabilizing effect on the heavy metals Cr, Pb, and Zn in the case of complex soil contamination with these metals. The investigated soil was acidic sand. Soluble element concentrations extracted by distilled water, ammonium acetate buffer, and ammonium-acetate + EDTA extractant were determined. The effect of lignite on the humus quality of the soil and its influence on the cation exchange capacity was also measured. The results were evaluated using analysis of variance, regression analysis, and principal component analysis. The results indicated that lignite was capable of stabilizing Pb, Zn, and particularly Cr. According to the optical method, lignite did not increase the amount of higher condensation and polymerization humic fractions, but it did increase the cation exchange capacity of the soil. If the lignite-based remediation technology is to become applicable in practice, further tests will be required on the efficiency of lignite, accompanied by a change in the scale of the experiments.

Contribution of Agricultural Field Production to Emission of Greenhouse Gases (Ghg)

Abstract According to global inventories the agricultural field production contributes in a significant measure to increase of concentration of greenhouse gases (CO2, N2O, CH4) in the atmosphere, however their estimated data of emissions of soil origin differ significantly. Particularly estimates on nitrogen-oxides emissions show a great temporal and spatial variability while their formations in microbial processes are strongly influenced by biogeochemical and physical properties of the soil (eg microbial species, soil texture, soil water, pH, redox-potential and nutrient status) and land use management through the impact of the application of natural and synthetic fertilisers, tillage, irrigation, compaction, planting and harvesting. The different monitoring systems and inventory models were developed mostly from atmospheric chemistry point of view and little comprehensive data exist on the processes related to GHG emissions and their productions in agricultural soils under ecological conditions of Central Europe. This paper presents the new results of a project aimed elaboration of an experimental system suitable for studying relationships between the production and emission of greenhouse gases and plant nutrition supply in agricultural soils under Hungarian ecological conditions. The system was based on a long-term fertilisation field experiment. Mesocosm size pot experiments were conducted with soils originating from differently treated plots. The production of CO2 and N2O was followed during the vegetation period in gas traps built in 20 cm depth. Undisturbed soil columns were prepared from the untreated side parcels of the field experiment and the production of CO2 and N2O was studied at 20, 40 and 60 cm depth. A series of laboratory microcosm experiments were performed to clarify the microbial and environmental effects influencing the gas production in soils. The CO2 and N2O were determined by gas chromatography. The NOx was detected by chemiluminescence method in headspace of microcosms. In the mesocosm and soil columns experiments influence of plant nutrition methods and environmental factors was successfully clarified on seasonal dynamics and depth profile on CO2 and N2O productions. The database developed is suitable for estimating CO2 and N2O emissions from agricultural soils. Abstrakt Światowa produkcja rolnicza przyczynia się znacząco do zwiększenia stężenia gazów cieplarnianych (CO2, N2O, CH4) w atmosferze, jednak dane szacunkowe dotyczące tych emisji pochodzących z gleby różnią się istotnie. W szczególności dotyczy to tlenków azotu, których emisja wykazuje dużą zmienność czasową i przestrzenną, podczas gdy ich tworzenie w procesach mikrobiologicznych jest silnie uzależnione od biogeochemicznych i fizycznych właściwości gleby (np. gatunków mikroorganizmów, struktury gleby, wód glebowych, pH, potencjałów redoks i substancji odżywczych) oraz wpływu zarządzania gruntami poprzez stosowanie nawozów naturalnych i sztucznych, rodzaju uprawy, nawadniania, sadzenia i zbiorów. Różne systemy monitorowania i modele inwentaryzacyjne zostały opracowane głównie z punktu widzenia chemii atmosferycznej. Istnieje niewiele całościowych danych dotyczących emisji gazów cieplarnianych i ich produkcji w glebach rolniczych w warunkach ekologicznych Europy Środkowej. Przedstawiono nowe wyniki prac realizowanych w ramach projektu dotyczącego opracowania systemu doświadczalnego, odpowiedniego do badania relacji między produkcją i emisją gazów cieplarnianych a nawożeniem roślin w węgierskich warunkach ekologicznych. Eksperyment oparty był na długotrwałym doświadczeniu polowym. W doświadczeniach wykorzystano gleby pochodzące z różnych działek. W okresie wegetacyjnym produkcja CO2 i N2O była śledzona za pomocą pułapek gazowych umieszczonych na głębokości 20 cm. W celu wyjaśnienia wpływu procesów mikrobiologicznych i środowiskowych na produkcję gazu w glebie wykonano szereg mikroskalowych doświadczeń laboratoryjnych. Stężenia CO2 i N2O oznaczano metodą chromatografii gazowej. Stężenia NOx w górnych obszarach badanych mikrosystemów oznaczano metodą chemiluminescencji. W mezoskali i w kolumnach glebowych eksperymenty dotyczące wpływu metod dożywiania roślin i czynników środowiskowych z powodzeniem wyjaśniały dynamikę zmian sezonowych i produkcję CO2 i N2O w profilu głębokościowym. Opracowana baza danych jest odpowiednia do oszacowania emisji CO2 i N2O z gleb rolnych.