[en] Complete text of publication follows. One of the best preserved terrestrial records of past climate are in loess-palaeosol sequences around the world. Except classical Chinese loess, European sequences are widely used for palaeoenvironmental reconstructions. Low Danube loess deposits are part of the south-eastern loess cover, linking loess belt in Asia with Central European loess. Its magnetic properties have been extensively studied, putting emphasis on present continental conditions. In the present work, role of Black sea as climatic factor playing role in setting up rock magnetic properties of samples from Durankulak loess outcrop have been studied. Combined use of magnetic and DRS data show that magnetic enhancement of palaeosols is accompanied by an increase of hematite content, suggesting that pedogenic maghemite (magnetite) and hematite are simultaneously formed during warm interglacial periods. Comparison with data from a loess-palaeosol section in the countryside (away from maritime climates) suggests that more humid and warmer conditions favour faster growth of pedogenic Fe oxides towards stable SD magnetic grain sizes. Possible role of diagenetic effects will be discussed.

[en] Highlights: • Magnetic susceptibility of ash-rich and mineral burnt soil monitored during 3 years • Fine grained magnetite/maghemite is the main magnetic mineral in ash and burned soil • Magnetic enhancement continues rising several days after fire event. • Pyrogenic Fe-oxides appear during - and post-fire due to enhanced microbial activity. • Oxidation of pyrogenic magnetite with time leads to magnetic susceptibility decrease. -- Abstract: Wildfires strongly affect soils, including iron biogeochemical cycling and carbon storage. Thus, it is important to reveal the dynamics of iron oxide synthesis and transformations during and after a wildfire. This study investigates the temporal stability of strongly magnetic minerals appearing after a wildfire. Following a designed experimental fire, samples from vegetation ash and mineral soil were taken immediately after and at progressively longer time intervals. The magnetic susceptibility monitoring of samples during three years period demonstrates an initial increase in magnetic signal of ash-rich material taken immediately after the fire followed by a gradual decrease over time. The behavior of samples collected later after the fire showed only a moderate decrease. It is suggested that the magnetic susceptibility rise during the laboratory storage could be due to the increased availability of nutrients and microbial activity immediately after the fire and related intense redox reactions involving iron oxide particles. The decreasing trend in magnetic susceptibility is ascribed to the oxidation of ultrafine magnetite particles with time. All mineral soil samples from the deeper level showed an initial susceptibility increase, assigned to a similar process. Magnetic susceptibility monitoring was also carried out on samples gathered shortly after natural wildfires. The soil samples affected by strong and long wildfires show a decrease in magnetic susceptibility with time. This effect is more pronounced in the surface black-colored ash layer. The ash material from a site disturbed by a strong short wildfire demonstrates behavior similar to the ash from the experimental fire. It is supposed that the temporal evolution of magnetic susceptibility of the mineral alteration products of wildfires is influenced by the grain size of the produced iron oxide particles, their redox reactions mediated by the heterotrophic bacteria, as well as the amplifying role of pyrogenic carbon for intensification of the redox reactions.

[en] Pilot study on soil contamination degree around the Maritza East thermal power plants, evaluated through applying magnetic methods, is presented. The magnetometry method is based on the well-established fact that anthropogenically contaminated with fly ashes soils display enhanced magnetic susceptibility, as well as other specific magnetic characteristics. Results from the magnetic investigations carried out in our study evidence significant soil contamination near the pollution sources and decreasing degree of anthropogenic load further away. The method applied is economically more efficient compared to classical physical and chemical methods for evaluation of soil contamination.

[en] Highlights: • Copper smelter and Cu mining extremely pollutes urban areas. • Magnetic proxies of road dust strongly correlated to hazardous elements. • Mining, smelting, ore transportation and traffic are major pollution sources. • Susceptibility threshold values are suggested for approximating Pollution Load Index. • Significant non-carcinogenic and carcinogenic health risk was identified. This study aims to evaluate the urban pollution by combined magnetometric and geochemical analyses on road dusts from three towns in the vicinity of Cu-smelter and ore mining. A collection of 117 road dust samples was investigated for their magnetic characteristics (magnetic susceptibility (χ), frequency dependent susceptibility, anhysteretic and isothermal (IRM) remanences), IRM step-wise acquisition and thermal demagnetization. Coarse grained magnetite and hematite were identified as major iron oxides in the emissions from ore spills and smelter, while traffic-related magnetic minerals were finer magnetite grains. Degree of pollution is assessed by geo-accumulation index, enrichment factor and Pollution Load Index (PLI) for a set of potentially toxic elements (PTEs). Using the geochemical data, we evaluate the carcinogenic and non-carcinogenic health risks for the population. Our results show that dust emissions from the industrial facilities likely pose significant health hazard for adults and children caused largely by Arsenic pollution in “hot spots”. Based on the strong correlation between χ and most of the PTEs, detailed variations in pollution degree inside the urban areas are inferred. Strong linear regression between χ and PLI allows designating limit susceptibility values, corresponding to the PLI categories. This approach can be successfully applied for monitoring and mapping purposes at high spatial and temporal resolution.