One of the most important ores for REE mineralization are iron oxide–apatite (IOA) deposits. The Posht-e-Badam Block (PBB) is a part of the Central Iranian geostructural zone which is the host of most important Fe deposits of Iran. Exploration studies of the IOA deposits within the PBB (e.g. Esphordi, Gazestan, Zarigan, Lak-e-Siah, Sechahoun, Chahgaz, Mishdovan, Cheshmeh Firouzi and Shekarab) demonstrate that these deposits contain high contents of REE. Concentrations of ΣREE in the most important IOA deposits of the PBB include the following: the Esphordi deposit varies between 1.2 and 1.88%, the Gazestan deposit between 0.17 and 1.57%, the Zarigan deposit between 0.5 and 1.2% and the Lak-e-Siah deposit varies between 0.45 and 1.36%. Concentrations of ΣREE within the apatite crystals present within the IOA ores in the Esphordi, Lak-e-Siah and Homeijan deposits have ranges between 1.9–2.54%, 1.9–2.16% and of 2.55%, respectively. These elements are mainly concentrated in apatite crystals, but other minerals such as monazite, xenotime, bastnasite, urtite, alanite, thorite, parisite–synchysite and britholite have been recognized as hosts of REEs, as small inclusions within the apatite crystals, and in subsequent carbonate, hematite–carbonate and quartz veins and veinlets. Given the extent of this block and the presence of several IOA deposits within this block, and also the high grades of REEs within these deposits, one can reasonably state that it is obvious that there are significant resources of REEs in this part of Iran.
The Ecse-halom is a burial mound (kurgan) in the Hortobágy region of Hungary. Built in the Late Copper Age/Early Bronze Age by nomadic people from the east, it now stands on the border between two modern settlements. A road of medieval origin runs along this border and cuts deeply into the body of the mound. The southern half of the mound was plowed and used as a rice field, and later a military observation tower was built on top of it. Despite this disturbance, the surface of the mound is in decent condition and provides a home for regionally significant, species-rich loess steppe vegetation. The mound comprises two construction layers as indicated by magnetic susceptibility and thin-section micro-morphological analysis. Examination of organic compounds and carbonate content at various levels showed different values, which suggest a variety of natural and anthropogenic stratigraphic layers. Mid-sized siltstone fraction is dominant in the section. The layers originate from the immediate vicinity of the mound, but have different characteristics than present-day soils. These mounds contain a valuable record of cultural and environmental conditions occurring at the time of their construction, and also serve as a refuge for ancient loess vegetation; therefore their conservation is highly recommended.
Sideritic—kaolinitic and green clay layers were previously reported from the Mecsek Mountains (SW Hungary) as indicators of Tethyan volcanism in the otherwise germanotype Middle Triassic succession. The aim of the present study is to provide a review and a critical re-evaluation of the previously published data on both the sideritic—kaolinitic layers (the so-called “Mánfa Siderite”) and the green clay layers. New results of mineralogical investigation of the green clay layers are also presented. The Middle Triassic volcanic origin of the “Mánfa Siderite” cannot be confirmed. In addition to a possible volcanic contribution, the sideritic—kaolinitic layers were probably formed in a freshwater swamp under humid, tropical climatic conditions, whereby weathering in an organic-rich, acidic environment led to the formation of “underclays” and siderite in the coal-bearing formations of Late Triassic to Early Jurassic age. These layers were probably tectonically placed over Middle Triassic carbonates. The illitic green clay layers intercalated in the Middle Triassic dolostone may represent terrigenous deposits, and the illite mineralogy probably is the result of burial diagenesis of detrital clays.
The Mócs chondrite was studied by optical microscopy, element mapping, as well as scanning electron microscope backscattered electron (SEM—BSE) imaging, in order to gain a better understanding of the thermal metamorphic as well as post-shock annealing evolution and the mineralogical signatures in this meteorite. The studied thin section of Mócs meteorite contains 26 chondrules with a variety of chondrule textures, which are characterized by a blurry rim. The chondrules mostly consist of pyroxene and olivine, whereas feldspars occur only in the recrystallized groundmass, chondrule mesostasis, and mineral melt inside and beyond the shock veins. It was found that the matrix was completely recrystallized. According to the scanning electron microscope and optical microscope observations mentioned above, it can be concluded that the Mócs chondrite is a 6.5 petrographic type.
Knowledge of the distribution and sorption characteristics of trace metals in soils is essential because of their importance both from agricultural and environmental point of view. In this paper, an overview will be provided on the relationship between the behavior and sorption properties of Cu and Pb as well as major soil characteristics, based on the results obtained by several independent research projects carried out on this field at the Institute for Geological and Geochemical Research over the last 15 years. These projects were accomplished using methods with different approaches, e.g. studying metal characteristics by total metal content, selective chemical extractions and batch sorption experiments.Our results show that both metals can be found in soils, primarily in the form of phases highly resistant to weathering. However, if they are mobilized, they are easily and strongly immobilized by soils rich in organic matter, with higher affinity for Cu than for Pb. In acid soils, on the other hand, the leaching of Cu is expected to be higher from such horizons when compared to Pb, especially when iron oxides, which immobilize Pb preferentially, are also present in these horizons. In mineral horizons the close association of Pb and iron oxides can be still expected, whereas Cu prefers to be bound both by clay minerals and iron oxides. In alkaline soils, however, precipitation of both metals as carbonates is a general feature. Our results obtained through different approaches presented in this paper were found to be effectively complementary to each other, providing a much deeper insight into soil-metal interaction than when they are used independently.
High concentration of naturally-occurring arsenic in groundwater poses a significant risk to human health if this water is a drinking water resource. Chronic arsenic ingestion has been linked mainly to skin cancer, and a wide variety of non-cancer health impacts. Research conducted in Hungary shows that there is an excessive risk of arsenic-related diseases in populations consuming water that exceeds the 10 microgram/liter limit value. It is therefore important to understand the significance of reduction of arsenic concentration in drinking water and the size of the exposed population.
A field experiment with microelement loads was set up on loamy-textured, calcareous chernozem soil formed on loess. The ploughed layer contained about 5% CaCO3 and 3% humus. The soil was well supplied with Ca, Mg, Mn and Cu, moderately supplied with N and K, and weakly supplied with P and Zn. The water table is at the depth of 15 m, the water-balance of the area is negative, and the site is drought-sensitive. Salts of the 13 examined microelements were applied at 4 levels in the spring of 1991.Treatments were arranged in split-plot design, in a total of 104 plots with two replications. Loading rates were 0, 90, 270 and 810 kg/ha per elements in the form of AlCl3, NaAsO2, BaCl2, CdSO4, K2CrO4, CuSO4, HgCl2, (NH4)6Mo7O24, NiSO4, Pb(NO3)2, Na2SeO3, SrSO4, and ZnSO4. Soil profiles of the control and the 810 kg/ha treatment were sampled in the 3rd, 6th and 10th year of the trial. The mixed samples, consisting of 5 cores/plot, were taken every 30 cm to the depth of 60 (1993), 90 (1996) and 290 (2000) cm. NH4-acetate + EDTA-soluble element content was determined. The scheme for vertical movement of soluble elements in soil profile as a function of time is shown in Fig. 1. The main conclusions of the study can be drawn as follows:
On contaminated soil with 810 kg/ha loading rates, As, Hg, Ni, Cu, Pb, Ba and Sr displayed no significant vertical movement. The movement of these elements is blocked in the soil-plant system: their accumulation in the above-ground plant parts usually remains below 5–10 mg/kg D.M., with the exception of Ba and Sr which showed a somewhat higher accumulation. On this soil the above elements do not seem to be dangerous contaminants either to soil, groundwater or plants. Extreme As and Hg loads, however, resulted in phytotoxicity in some plants.
Moderate extent of leaching occurs in the case of Zn and Cd, when they are enriched significantly. Their accumulation was moderate in the above-ground plant parts. Zn is not a dangerous pollutant either for soil, plants or groundwater at this site. Cd, however, is a very dangerous element from the human toxicological point of view and more extreme Cd loads also proved to be toxic for soil life, crops yield and quality.
Cr, Se, and Mo (in the form of chromate, selenate and molybdenate anions) exhibited great mobility in the soil and partly in the soil-plant system. Cr was hardly detectable in the above-ground floral parts. Its rapid leaching, however, can jeopardize groundwater quality. Se showed hyperaccumulation in all plant organs with high toxicity for all kind of crops. Mo also showed two or three orders of magnitude greater accumulation in plant parts, resulting in products unfit for animal or human consumption. Under our experimental conditions Cr(VI), Se, Mo can be classified as dangerous contaminants, since the anion forms remained stabile for a long time in this well-aerated calcareous environment.
South of the Sudetes and Tatra Mountains young sediments contain more of almost all micro- and mesoelements than those to the north of the Carpathian Mountains, which were covered by ice during the Late Pleistocene. As detailed investigations show this larger unit is a collection of many individual geochemical regions, among which there are four on the area of Hungary: the region of soil calcification in the central part of Hungary, the slope debris of the foothills of the Eastern Alps, the floodplains of the rivers of Eastern Hungary that are contaminated with the waste material of heavy industry, and the rest of the country. No general geochemical background can be given to the whole; the background value intervals for each element shall be given for each geochemical region separately. In Eastern Hungary, where those rivers flow that originate from the heavy industrial centers of Transylvania and Slovakia, the toxic elements can locally exceed the limit value. In the central part of the country, however, the micro-elements are frequently found below the minimum concentration required, since a carbonate accumulation zone develops above the groundwater level and the carbonate minerals contain low amounts of nutrient elements.
The aim of this paper is to examine the relationship between soil properties and potentially toxic element contents of arable soils based on the dataset of the Soil Information and Monitoring System in Hungary. Nine potentially toxic elements (As, B, Cd, Co, Cr, Cu, Ni, Pb, Zn) were compared with selected soil parameters. We carried out grouping of related soil properties by principal component analysis. The method was suitable to describe the relationship within groups of the soil properties. We studied correlations of the resulting components and potentially toxic elements. The change of Ni content was influenced by the physical properties of the soil (e.g. clay content, field capacity, R = 0.67). Boron is the only one of the examined elements that indicates significant positive correlation with saline-alkali (R = 0.21) parameters. Zn, Co and Cr behaved very similarly; their correlation with components 1 and 2 were the closest.