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Lead contamination in soils and sediments is a major threat to water quality. In surface and near-surface environments, Pb is not redox active; however, common Pb hosts, including Fe(III)-(hydr)oxides and sulfides, dissolve and precipitate as redox conditions change. Dissolution of Pb hosts may release Pb to porewater, leading to spikes in dissolved Pb concentrations and potential transport into surface or groundwater. Here, we examine the impacts of hydrologically coupled redox transitions on Pb partitioning in contaminated floodplain soils. We find that the affinity of Pb for particulate organic matter (POM), inclusive of mineral-associated organic matter, ensures that across redox transitions Pb is retained in the solid phase, despite host-phase (Fe(III)-(hydr)oxide and sulfide) dissolution. As seasonal hydrologic dynamics shift porewater redox conditions, Pb-bearing Fe(III)-(hydr)oxides (Pb-HFO) and sulfides (PbS) are dissolved and (re)precipitated. However, despite these shifts in redox conditions and associated host-phase transformations, Pb retention on POM, coupled with the formation of PbS and Pb-HFO, maintains dissolved Pb concentrations below 17 μg L

The concentrations of 28 polychlorinated biphenyls (PCBs) were determined in soils collected at three depths from thirteen different sites along the floodplain of the lower reaches of the River Niger (LRRN) in Nigeria. The aim of the study was to provide data on the levels of contamination, sources of the contaminants, and risks to the ecosystem and humans. Soil samples were Soxhlet extracted with a solvent mixture of dichloromethane (DCM)/n-hexane and cleaned up on a column packed with Florisil and silica gel. The PCBs in the samples were quantified by gas chromatography-mass spectrometry. The Ʃ28 PCB concentrations in the floodplain soils varied between not detected (nd) and 11,151 ng g−1 for different sampling sites and depths. The PCB concentrations and homologue distribution patterns in soil profiles of the floodplain of the LRRN showed remarkable differences with respect to sites and depths. The results obtained were used to evaluate the ecological and human health risks, which indicated that there is a potential risk to organisms and humans from exposure to PCBs in these soil profiles. The source evaluation as determined by principal component analysis suggested that PCBs in these soil profiles came from burnt circuit boards, cable wires, use of paints, discharges from transformers, long-range migration, and deposition.

The pollution of floodplain, deltaic and adjacent coastal soils in large fluvial systems, considered an urgent environmental problem, as well as potentially toxic elements in such environments, can negatively affect aquatic ecosystems, as well as pose significant risks to human health. This paper is devoted to the geochemistry of potentially toxic elements in soils of the Lower Don basin, which is one of the largest and most anthropogenically transformed water bodies in Southern Russia, as well as the adjacent areas of the Taganrog Bay coast. The median element concentrations in the soils of the study area were consistent with the world soil average and the contents of elements in background soils. Comparative assessment of the spatial distributions as well as the results of Pearson’s correlations, cluster analysis and principal component analysis showed that Cr, Ni, Cu and Zn are predominantly of natural origin; Mn and As are of mixed sources; and Cd and Pb are predominantly of anthropogenic origin. The geochemical anomalies of elements were associated with the impact of local anthropogenic sources. Geochemical background values for Cr, Mn, Ni, Cu, Zn, As, Cd and Pb in the soils of the Lower Don and the Taganrog Bay coast determined using the ‘median + 2 median absolute deviations’ approach are presented. The highest values of the integrated pollution indices were observed in floodplain soils of small rivers.

Denitrification in floodplain soils is one key process that determines the buffering capacity of riparian zones in terms of diffuse nitrate pollution. One widely used approach to measure the denitrification potential is the acetylene inhibition technique that requires fresh soil samples. We conducted experiments with air-dried soils using a time series analysis to determine the optimal rewetting period. Thus, air-dried soil samples from six different floodplain areas in Germany were rewetted for 1 to 13days to 100% water-filled pore space. We analyzed nitrogen accumulated as N2O in the top of anaerobic flasks with and without acetylene by gas chromatography after four hours of incubation. We observed an overall optimal rewetting of at least seven days for complete denitrification. We also saw the strong influence of pH and field capacity on the denitrification product ratio, in soils with pH &lt, 7, we hardly assumed complete denitrification, whereas the treatments with pH &gt, 7 achieved stable values after seven days of rewetting. This advanced method provides the opportunity to carry out campaigns with large soil sample sizes on the landscape scale, as samples can be stored dry until measurements are taken.

Пожалуйста, вставьте свой абстрактный HTHigh anthropogenic impact and the rate of urbanization result in a decrease of urban soils’ capacity to perform ecosystem services. Carbon sequestration is an important soil-based ecosystem service, which can be assessed through quantity and quality soil carbon stocks. The stability of soil organic matter (SOM) is characterized by the resistance of its constituent components to biological, chemical and physical destruction. In the study, SOME stability in peat-sand mixture used for urban soils’ construction; floodplain soil was analyzed in response to temperature-moisture conditions. The decomposition rate of various soils was assessed. Decomposition was assessed through studying microbial production of CO2. In the research the CO2 emissions were studied under following temperatures and moisture conditions: temperature – 7°C, 22°C, 30°C and 40°C and moisture – 0.2 WHC, 0.4 WHC, 0.6 WHC, 0.8 WHC, 1 WHC. Moisture affects the amount and activity of microbial biomass, controls the availability of oxygen to microorganisms, causes periods of water microbial stress and also can destabilize organic matter, resulting in increased availability of carbon to soil microorganisms. Different patterns of moisture and temperature impacts on the soil organic carbon (SOC) decomposition rates were observed. It was concluded that, depending on the qualitative composition of carbon, the impact of hydrothermal conditions on the emission of carbon dioxide changed.ML здесь.

The northwestern part of the Acre State (Brazil) possesses singular soils in Brazilian Amazonia, but have been very little studied. This study aimed to discuss the genesis and some micropedological aspects of the soils from Serra do Divisor and adjacent floodplain soils of the Moa river, to enhance the knowledge on their formation. A toposequence of soils ranging from the uppermost part of sub-Andean Serra do Divisor to the Alluvial soils of Moa river floodplain was studied, regarding chemical, physical, mineralogical, and micromorphological attributes. The parent material of the Serra do Divisor is basically quartzose sandstone, and the soils along the toposequence were classified as Typic Haplorthods (P1), Spodic Quartzipsamment (P2), Lithic Quartzipsamment (P3), and Lithic Quartzipsamment (P4). Along the Moa river floodplain, we also identified and collected, Typic Udifluvent (P5), Typic Kandiudult (P6), Typic Kandiudalf (P7), and Arenic Plinthic Kandiudult (P8). The Serra do Divisor soils have very low fertility, high acidity, and low cation exchange capacities, presenting a coarse sandy texture, even shallow pedons. The X-ray diffraction analysis of these soils indicates the predominance of kaolinite, with traces of quartz and gibbsite. The shallow mountain Podzols on sandstone have an expressive accumulation of organic material in surface horizons, with evidence of ferrihydrite and imogolite in the subsurface. At the Moa river floodplain, all soils are originated from recent sediments (Cenozoic), which have a geological source upstream. Varying sedimentary layers are key aspects influencing soil genesis. Those soils have evidence of 2:1 clays with hydroxyl-Al interlayers in subsurface horizons. The Serra do Divisor steep landforms and the coarse texture of the soils promote good drainage and favor leaching and chemical impoverishment. Kaolinite and gibbsite were formed by severe leaching and there are evidences of in situ neoformation of gibbsite by extreme Si losses. All studied soils have some peculiarities such as high accumulation of organic material or 2:1 clay minerals. Most investigated soils were affected by colluvial, reworking, mass movements or a strong variation on sedimentation. Made available in DSpace on 2020-09-01T04:41:32Z (GMT). No. of bitstreams: 1 27023.pdf: 8321405 bytes, checksum: eefac5e697251c464a1a8584ea3f5456 (MD5) Previous issue date: 2020

The soils developed from the Ganges sediments in the coastal area of Bangladesh and India extend several thousand hectares and important from the view point of rice cultivation. Phosphorus, one of the important environmental and agricultural element, retention behavior of the Ganges floodplain soils is poorly reported. The objective of this study was to determine maximum phosphorus adsorption capacity (MPAC) and to develop Psat for 13 Ganges Tidal Floodplain soils of Bangladesh. The MPAC value and Psat based on Mehlich-3 extractions were determined. The conventional adsorption equations, such as the Langmuir, Freudlich and Temkin equations were used to describe the P sorption of the studied soils. The MPAC value varied from 1250 to 2000 mg/kg and correlated with EC (r = 0.59, p

CORRECTION: Due to a number of formatting and layout issues, the PDF of this paper was replaced on 10th October 2016. The page numbers of this article have changed from 55-61 to 57-63. The present investigation aimed to evaluate different fractions of P of Ganges tidal floodplain soils of Bangladesh in terms of plant availability in the selected soil. The samples were analyzed for solution P, labile pool, alkali-extracted inorganic pool, organic pool, acidic pool and residual P.The soil solution P in the tested soils ranged from 0.03 to 0.11 mg L –1 . The concentration of 0.5M NaHCO 3 extracted P had a range of 8-34 mg kg –1 . Dilute NaOH extracted inorganic P had a range of 25-59 mg kg –1 . NaOH extracted organic P ranged from 334 to 542 mg kg –1 and acid extracted P represented from 140 to 443 mg kg –1 , respectively. Residual P of the tested soils showed a concentration of 104-262 mg kg –1 . On average of the 12 soils, the relative concentration of solution P was 0.01%, NaHCO 3 P was 3.2%, NaOH-Pi was 6.8%, NaOH-Po was 44.6%, acid pool was 27.3% and residual fraction was 18.1%. Different P pools showed strong correlation either with sand, silt, clay, electrical conductivity, pH(H 2 O), pH (KCl), organic carbon or extractable Fe content. The tested Ganges tidal floodplain soils demonstrated wide variation in the relative proportion of different P pools. Bangladesh Rice j. 2015, 19(2): 57-63

The study was set up to characterize floodplain soils of Southern Guinea Savanna in North Central Nigeria for sustainable land use. The flexible grid method was adopted to identify the soil units. Soil map was produced in a GIS environment, using morpho-physical and soil chemical properties. The major morphological expressions are ferrolyses and gleization. The variation in cation exchange capacity recorded (1.29–21.64 cmol kg− 1) could be attributed to effects of various deposits of soil regoliths from time to time. The phosphorus distribution is generally low (0.8–11.8 mg kg− 1) while nitrogen content is > 0.15% at the surface. The major pedogenetic processes include cummilization, ferrolyses and gleization. The soil units identified were classified as Fluvaquentic Epiaquept, Aquertic Ustifluvent, Kandic Ustifluvent, and Aeric Ustipsamment. The mapping units suggest two possible management units based on texture and chemical properties. The soils are generally suitable for rice production due to epi-saturation.

Arsenic (As) accumulates in rice grain from contaminated irrigation water and soils may vary with the land types and water receiving basins. Two confined and one unconfined basins comprised of different land types in the As contaminated Ganges River Floodplain soils of Faridpur district of Bangladesh were selected to assess the contribution of different land types on spatial distribution of As uptake by rice grain. Sites in Faridpur Sadar and Madhukhali upazilas were confined basins, while a third site in Boalmari upazila was an unconfined basin connected to a river. Each site consisted of a mosaic of between 16-31 shallow tube well (STW) irrigation command areas with water As concentrations ranging from about 20 to 170 ?g-l in Faridpur and Boalmari sites and 20-110 ?g-l in Madhukhali site. Soil arsenic concentrations ranged from about 4-42, 5-31 and 5-29 mg kg-1 in Madhukhali, Faridpur Sadar and Boalmari, respectively, while the resultant rice grain As were 0.22 - 0.69, 0.095 – 0.751 and 0.030 – 0.92 mg kg-1, respectively. Arsenic concentrations in rice grain of different sites were in the order of Madhukhal>Faridpur Sadar>Boalmari basin. Arsenic accumulated high in the confined basins because of its less mobilization while more mobilization and loss of As in the open unconfined basin was obvious which materialized in the rice grain arsenic of the corresponding study sites.J. Environ. Sci. & Natural Resources, 8(2): 51-55 2015

Four field experiments were carried out with Binadhan 7 at Birgonj, Dinajpur; Debigonj, Panchagarh; Kaligonj, Lalmonirhat and Pirgonj, Rangpur during T.aman (kharif II) season of 2011 in the Old Himalalayan Piedmont Plain (AEZ 1) and Tista Meander Floodplain Soils of North-West Bangladesh. The experiments were designed with eight treatments and laid out in randomized complete block design (RCBD) with three replications. The treatment combinations were: T 1 (100%STB), T 2 (T 1 + 25% N), T 3 (T 1 + 25% NP), T 4 (T 1 + 25% NK), T 5 (T 1 + 25% PK), T 6 (T 1 + 25% NPK), T 7 (75% of T 1 ) and T 8 (Control). Results indicated that application of different fertilizers significantly affected the grain yield at all of the four locations. The highest grain yield was found in treatment T 6 (T 1 + 25% NPK). Statistically identical yield was observed in treatments T 3 , T 4 and T 5 at Dinajpur; T 3 at Panchagar; T 2 , T 3 , and T 4 at Lalmonirhat and T 2 at Rangpur. All the treatment combinations gave significantly higher grain yield over the control at all of the locations. The highest straw yield was found in treatment T 6 (T 1 + 25% NPK). Statistically identical straw yield was found in T 3 and T 4 at Dinajpur; T 1 , T 4 and T 5 at Panchagar; T 2 , T 4 , T 5 and T 7 Lalmonirhat and all treatments except T 7 and T 8 at Rangpur. Significantly the lowest yield was obtained in the control treatment (T 8 ) in all of the locations. The highest total N uptake was observed in treatment T 6 at all of the four locations. For total P uptake, the similar trend of total N uptake was observed for all the locations. Treatment T 6 showed the highest uptake of total K at all locations. The highest uptake of total S was observed in treatment T 6 at Dinajpur, Panchagarh and Lalmonirhat. But the highest uptake of total S was observed in treatment T 3 at Rangpur. However, the lowest total N, P, K and S uptake was observed in control treatment (T 8 ) at all locations. The partial budget analysis of T.aman rice demonstrated the highest net benefit of tkha-1 85,598/-, 78,619/-, 58,308/- and 72,532/- in T 6 treatment followed by tkha-1 76,348/- in T 4 treatment, 71,100/- in T 3 treatment, 54,192/- in T 3 treatment and 68,247/- in T 2 treatment where the highest MBCR of 5.40, 3.75, 2.20 and 3.84 was also observed in T 6 treatment at Dinajpur, Panchagarh, Lalmonirhat and Rangpur, respectively. Based on most profitable treatments, fertilizer doses of N 80 P 8 K 40 S 8 Zn 1 in Birgonj, Dinajpur; N 84 P 8 K 40 S 6 Zn 1 in Debigonj, Panchagarh; N 80 P 8 K 40 S 6 Zn 1 in Kaligonj, Lalmonirhat and N 81 P 8 K 35 S 8 Zn 1 in Pirgonj, Rangpur could be recommended for higher yield of Binadhan-7 rice in North-West Bangladesh. DOI: http://dx.doi.org/10.3329/jesnr.v6i2.22106 J. Environ. Sci. & Natural Resources, 6(2): 115-120 2013

On the earthworm fauna (Oligochaeta: Lumbricidae), in particular the distribution of Proctodrilus, in the floodplains of the chernozem and gray-brown podzolic soil areas on both sides of the Ore Mts. In a study of mineral soils in floodplains, shallow depressions, and dry valley heads of the Saale-Elster plateau in eastern Germany and along the lower Eger/Ohře river in Czechia, sixteen earthworm species were found. On the basis of these findings, areas of gray-brown podzolic soils can be differentiated from chernozem areas mainly by the occurrence in the former of the two species Proctodrilus antipai and P. tuberculatus. In a section of one floodplain in the gray-brown podzolic soil area, the distribution of these two earthworm species shows a vicariance situation, such that P. antipai is restricted to the outer edges of the floodplain while P. tuberculatus inhabits the parts close to the river. In the chernozem areas, on the other hand, P. antipai is the only one of the two species to occur, and is also found in those areas close to the river. P. tuberculatus disappears in the transitional zone between a floodplain where it occurs and a chernozem floodplain. The distribution of P. antipai ends where a floodplain inhabited by it graduates into one belonging to a large river with a high rate of flow. On the stretch of the Elbe near Mlekojedy, where the position of the confluence with the Ohře has migrated over time, the vicariant distribution of the two species within the soil profile was noted. Here P. antipai is found in the uppermost soil layer, while P. tuberculatus lives in the lower-lying mineral soil at the same location. This ecological vicariance appears to represent different stages of clay translocation in flood loam. The results show that P. tuberculatus is dependent on such clay translocation or lessivage, and where this soil-profile-influencing process cannot take place the species does not occur. Examples would be oligotrophic acid montane brown forest soils, eutrophic brown forest soils, and chernozems, as well as the floodplain soils derived from all three.

This study was conducted at farmers’ fields in Chandina, Cumilla of Bangladesh covering soils of Old Meghna Estuarine Floodplain to find the effect of micronutrient application to tomato in floodplain soils. Randomized complete block design with 3 replications was used in the experiment where seven treatments including a control were tested. The treatments were formulated taking six micronutrients, i. e., Zn, B, Cu, Mn, Fe and Mo at the rate of 3, 2, 2, 3, 5 and 1 kg ha-1, respectively. The treatments were designed following the additive element trial technique and N, P, K and S were applied at recommended rate equally to all plots. Fruit yield of tomato was affected significantly by the application of Zn alone but combine application of both Zn and B showed the highest responses. It was evident that the application of only Zn and B was sufficient to achieve a tomato fruit yield of 66.4 t ha-1 that was similar to the highest yielding (67.5 t ha-1) treatment (T7). The lowest yield (56.8 t ha-1) was in the control treatment. Stover yield and plant height did not respond significantly while only Zn was found responsive for fruit yield, fruit clusters and number of fruits per plant. Similar to fruit yield, protein content and in all cases, nutrient uptake were affected by the application of both Zn and B. It was noted that the application of Zn and B influenced different growth and yield parameters while the other four micronutrients tested did not have any effect. However, the combine application of Zn, B, Cu, Mn, Fe and Mo was beneficial for plant growth.

Phosphorus (P) availability, which depends on both P concentration and speciation, often controls primary productivity and algal-bloom formation in river systems. The river P pool is also connected to P pools of adjacent sediments, soils and vegetation. Thus, informed management of P in floodplain–river systems requires detailed understanding of P concentration and speciation in all of these interconnected components. We studied P speciation in river sediments and water, floodplain soils and river red gum (Eucalyptus camaldulensis) leaf litter from the Lower Murray region using conventional spectroscopic measurements, solution 31P nuclear magnetic resonance (31P NMR) spectroscopy, and leaching experiments to simulate floodplain re-wetting of leaf litter. Almost all (>85%) of the P in river sediments was in the orthophosphate form, whereas floodplain soils had higher proportions of organic P (PO) species. Both fresh and senescent river red gum leaf litter also had a much higher concentration of PO, primarily in the form of phytate. On submersion, there was a rapid (0–96h) loss of dissolved P from senescent leaves; release of dissolved organic carbon showed similar kinetics. Loss of P from the leaves included both organic and inorganic forms. The results have important implications for aquatic primary productivity and environmental management strategies.

Fractions studies were done to know how the zinc applied to different soils was distributed in to various fractions when the soils incubated under aerobic and anaerobic condition. The added zinc provided significant increase in exchangeable Zn both under aerobic and anaerobic conditions although anaerobic condition gave lower results than aerobic condition. The higher results were obtained at early stage of incubation and it gradually reduced as the incubation period proceeded to 90 days. These results showed all most similar trends for all the soils under study. In general, added zinc showed significantly higher results to the different fractions of soil Zn both under anaerobic and aerobic incubation with very few exceptions. The highest amount of added Zn (12 kg/ha) always produced greater results than the lower doses. Only exchangeable Zn was found higher in the 1st measurement at 15 DAI then gradually decreased but in other cases, gradual increase in zinc fractions was seen as the incubation study proceed to longer duration provided with very few exceptions. In many cases, the exchangeable-Zn found higher only at 15 DAI but sharply reduced at 30 DAI. In general, the Gray Terrace Soil produced the highest results followed by Non Calcareous Gray Floodplain and the lowest results were observed in Dark Grey Floodplain & Brown Floodplain Soil. DOI: http://dx.doi.org/10.3329/jsf.v9i1-2.14643 J. Sci. Foundation, 9(1&2): 9-15, June-December 2011

The concentrations of the USEPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in soils of the floodplain of the lower reaches of River Niger, Nigeria, were investigated following the Lagdo Dam flood disaster of 2012. The aim was to provide information on the extent of contamination, sources, and risks of PAHs in these soils. The concentrations of Σ16 PAHs in the floodplain soils ranged from 812 to 10,700 μg kg. The benzo(a)pyrene (BaP) toxic equivalence and incremental lifetime cancer risk (ILCR) factors were used to evaluate the risk of human exposure to PAHs in these soils. The concentrations of benzo(a)pyrene carcinogenic equivalence (BaP) and benzo(a)pyrene mutagenic equivalence (BaP) ranged from not detected to 4090 μg kg and not detected to 4150 μg kg, respectively. The total ILCR for children and adults was calculated as the summation of the individual risks through the three routes of exposure, (ingestion, dermal, and inhalation of vapor or dust). The values obtained indicate that there are 6450 and 4480 chances in one million equally exposed persons to develop the risk of cancer for children and adults, respectively, which were higher than the USEPA acceptable guideline value of one cancer case in one million (10) equally exposed persons. The PAHs source evaluation, using the diagnostic ratios and principal component analysis (PCA), indicated that the major sources of PAHs in these soils were fossil fuel combustion, gas flaring, wood combustion, traffic emissions, and input from petroleum.

The morphological properties of floodplains and their morphological classification are shown from the generalization of long-term studies. A detailed description of alluvial processes is given, and stages of alluvial soil formation are characterized. Zonal-geographic, hydro-geomorphologic, evolutionary, and geomorphologic-genetic regularities in soil geography are found. The properties of alluvial soils under sharply contrasting climatic conditions, e.g., humid and arid, are considered. The high biogenic ability of soils and intensity of the soil-forming process in floodplains are proved. Data characterizing the structure and properties of floodplain soils in particular river valleys and the main micromorphological diagnostic features of alluvial soils are given.

The species composition and structure of collembolan communities in floodplain soils were analyzed; a total of 65 species were found. The highest springtail species diversity was revealed in soils of birch-aspen forests. Collembolan communities in meadow soils were the most similar to those in the aspen forests of the second and third age classes. Prevalence of edaphic and hemiedaphic species is characteristic of soils of birch-aspen forests.

Two long-term submerged Eutric Gleysols (GLe) and two short-term flooded Eutric Fluvisols (FLe) with high organic carbon contents (Corg between 5.1 and 12.9%) were selected to characterize soil microbial communities at the Elbe River (Germany). Measurements included dehydrogenase activity (DHA), soil microbial carbon (Cmic), soil basal respiration (BR), metabolic quotient (qCO2), Cmic/Corg ratio, and phospholipid fatty acids (PLFA). PLFA biomass, DHA, and Cmic/Corg ratios were considerable lower in GLe's than in FLe's. Whereas the BR as well as qCO2 were higher in GLe's what seems to be an unspecific response of aerobic soil microorganisms to the long flooding period and the resulting short time for development following flooding. Cmic/Corg ratios were low in comparison to terrestrial soils. PLFA profiles were dominated by saturated fatty acids (FA). Principal component analyses (PCA) of FAs revealed clear differences among the four floodplain soils. In GLe's all fractions of PLFAs were lower tha...

Two long-term submerged Eutric Gleysols (GLe) and two short-time flooded Eutric Fluvisols (FLe) at the Elbe River (Germany) with high organic carbon contents (Corg between 4.9 and 11.6%) were selected to evaluate dehydrogenase activity (DHA), soil microbial carbon (Cmic), Cmic/Corg ratio, and phospholipid fatty acids (PLFA) to characterize and discriminate these soils with microbial parameters. DHA, Cmic and PLFA-biomass as well as Cmic/Corg ratios are considerable lower in GLe's than in FLe's what seem to be an unspecific response of aerobic soil microorganisms on the long flooding period and the resulting short time for development after last flooding. Cmic/Corg ratios are low in comparison to terrestrial soils. PLFA profiles were dominated by saturated fatty acids (FA). Principal component analyses (PCA) with the identified FAs revealed a clear discrimination among the four floodplain soils. In GLe's, all groups of PLFA, inclusive monounsaturated FA, are lowest and in FLe's highest. Polyunsaturated FA ...

Gleyzation-mediated leaching of radiostrontium from floodplain soils of the Krasnoyarsk Mining and Chemical Combine (MCC) activity zone [Atamanovskii Island (front part), Oseredysh Island (front part), and Berezovyi Island (rear part)] is studied with model systems. Leaching of radiostrontium from waterlogged soils is analyzed in terms of the model of anaerobic biosolubilization of gel films. The leaching of radiostrontium is found to correlate with that of iron, confirming the cosolubilization model. Addition of glucose (0.5%) as a stimulant for growth of iron-reducing microorganisms increases the dynamic coefficient of radiostrontium leaching, particularly in soils with lower organic matter content. The model experiments showed that the radiostrontium leaching rate from floodplain soil is higher by 2–3 orders of magnitude than that of radio-cesium, suggesting the possibility of escape of radiostrontium from the floodplain of the Yenisei River with the intrasoil runoff. This conclusion is supported by the experimental data on the 90Sr/137Cs ratio in the floodplain of the Yenisei River downstream of MCC (0.01–0.1).

The distribution of earthworms in 18 types of tundra, middle-taiga, alas, and floodplain soils of Yakutia has been studied. The species Eisenia nordenskioldi is typical of Yakutian soils. The area, population density, and seasonal dynamics of earthworms in permafrost-affected soils have been determined. It is shown that earthworms are absent in excessively moist peat-muck permafrost-affected soils, excessively dry soddy soils of alases (thermokarst depressions), and soddy alluvial soils under steppe communities. The best living conditions for earthworms are associated with meadow floodplain, meadow alas, and mucky calcareous soils.

The rare earth elements (REE), particle-size distribution and mineralogical composition in the

The contents of 90 Sr and 137 Cs and the pattern of their redistribution in the soil and plant cover of floodplain ecosystems have been assessed. It is shown that the radionuclide distribution across the floodplain and along the river flow is determined by the formation of a barrier to their migration near the river channel, at which less mobile 137 Cs accumulates. The soil and plant cover of the central floodplain are enriched with 90 Sr. Differences in radionuclide migration in floodplain soils and their input into plants are determined by the rela- tionship between the processes of their immobilization and migration with soil water.

Measuring soil organic carbon (SOC) in riparian forest soils affected by floods is crucial for evaluating their concentration and distribution along hydrological gradients (longitudinal and transversal). Hydromorphological factors (e.g., sedimentation vs. erosion, size of floodplain, flood recurrence) may be the cause of major variations in the concentration of organic matter and SOC in soils and could have a direct impact on C levels in soil profiles. For this study, SOC concentrations were assessed in riparian soils collected along transects perpendicular to the riverbanks which cross through inundated and non-inundated zones. Other soil properties (e.g., acidity, nitrogen, texture, bulk density) that may affect the concentration of SOC were also considered. The main purpose of this study was to assess SOC concentrations in soils subjected to flooding with those outside the flood zones, and also measure various soil properties (in surface soils and at various depths ranging from 0 to 100 cm) for each selected area. Across the various areas, SOC shows marked differences in concentration and spatial distribution, with the lowest values found in mineral soils affected by successive floods (recurrence of 0–20 years). SOC at 0–20 cm in depth was significantly lower in active floodplains (Tukey HSD test), with average values of 2.29 ± 1.64% compared to non-inundated soils (3.83 ± 2.22%). The proportion of C stocks calculated in soils (inundated vs. non-inundated zones) was significantly different, with average values of 38.22 ± 10.40 and 79.75 ± 29.47 t·ha−1, respectively. Flood frequency appears to be a key factor in understanding the low SOC concentrations in floodplain soils subjected to high flood recurrence (0–20 years).

International audience; Flood pulses are major drivers of river-floodplain processes. We investigated their effects on soil nitrogen (N) transformations along a lateral gradient from the river to a mature alluvial forest in the Thur River floodplain (NE Switzerland). Selected N pools (ammonium and nitrate) and N transformations (mineralization, nitrification and denitrification) in the topsoils were repeatedly quantified over a period of six months. During this period, the floodplain was affected by two flood events of different magnitude. Our results showed a distinct difference in size and temporal changes of N pools and transformation rates among functional process zones (FPZs) differing in flooding disturbance. A strong temporary increase in N mineralization in a FPZ with young soil on the frequently flooded gravel bars was the most prominent flood-related effect. This was most likely related to the fast-flowing water during inundation that deposited fresh dispersed sediments with a coarse sandy texture containing highly bioavailable organic N, and/or stimulated the turnover of existing N by destroying sediment aggregates already present before the flood. Increased N mineralization appeared to stimulate coupled nitrification-denitrification in this FPZ during the drying phase. In the more stable FPZs, N mineralization was not strongly enhanced by flooding, whereas nitrification and denitrification were also increased during the drying phase, however to a lesser degree than in the gravel bar soils. Based on our results we propose that floodplain zones characterized by short intensive floods with fast over-flowing water are "hot spots" and the drying phases after the floods are "hot moments" of N transformations.

study area was assessed with respect to its heavy-metal load on the basis of the current guideline values. The heavy-metal loads of the soils in the study area have ranges of

A novel mercury-specific sequential extraction procedure (SEP) for the assessment of mercury (Hg) speciation in soils and sediments, with emphasis on studying the interaction between Hg and organic matter (OM), was developed and tested. It was applied to determine Hg speciation in floodplain topsoils and surface sediments along the Hg-contaminated part of the river Elbe, and to simultaneously derive some information on the (re)mobilization potentials for Hg from these matrices. The majority of the total Hg in the ecosystem today is bound in the floodplains, which also still geographically reflect the historic emission record. Most of the Hg in both matrices is bound strongly to OM, suggesting low availability. However, distinct differences between Hg speciation in the floodplain soils and sediments were also discovered. Mercury deposited in the floodplains shows speciation patterns that indicate stronger fixation compared with Hg in the sediments. This difference is attributed to the association of Hg with larger quantities of OM, which presumably also has higher molecular weight (MW). By comparison, Hg in the sediments was distributed among weaker binding forms, which are more likely to liberate Hg. Particularly, sediments showed a total lack of sulfidic binding forms for Hg. Pronounced geographical trends were detected in the Hg speciation along the river transect, with a general downstream shift from weaker to stronger binding forms, probably due to increased association with OM. These studies indicate that Hg speciation in riverine ecosystems is dynamic and reflects the chemical mechanisms underlying (bio)geochemical processes like distribution and transport.

The study deals with the combined contribution of polycyclic aromatic hydrocarbons (PAHs) and metals to health risk in Delhi soils. Surface soils (0–5 cm) collected from three different land-use regions (industrial, flood-plain and a reference site) in Delhi, India over a period of 1 year were characterized with respect to 16 US Environmental Protection Agency priority PAHs and five trace metals (Zn, Fe, Ni, Cr and Cd). Mean annual ∑16PAH concentrations at the industrial and flood-plain sites (10,893.2 ± 2826.4 and 3075.4 ± 948.7 μg/kg, respectively) were ~15 and ~4 times, respectively, higher than reference levels. Significant spatial and seasonal variations were observed for PAHs. Toxicity potentials of industrial and flood-plain soils were ~88 and ~8 times higher than reference levels. Trace metal concentrations in soils also showed marked dependencies on nearness to sources and seasonal effects. Correlation analysis, PAH diagnostic ratios and principal component analysis (PCA) led to the identification of sources such as coal and wood combustion, vehicular and industrial emissions, and atmospheric transport. Metal enrichment in soil and the degree of soil contamination were investigated using enrichment factors and index of geoaccumulation, respectively. Health risk assessment (incremental lifetime cancer risk and hazard index) showed that floodplain soils have potential high risk due to PAHs while industrial soils have potential risks due to both PAHs and Cr.

Environmental pollution by mercury is a world-wide problem. Particularly floodplain ecosystems are frequently affected. One example is the Elbe River in Germany and its catchment areas; large amounts of Hg from a range of anthropogenic and geogenic sources have been accumulated in the soils of these floodplains. They serve as sink for Hg originating from the surface water of adjacent river. Today, the vastly elevated Hg contents of the floodplain soils at the Elbe River often exceed even the action values of the German Soil Conservation Law. This is especially important as Hg polluted areas at the Elbe River achieve several hundred square kilometres. Thus, authorities are coerced by law to conduct an appropriate risk assessment and to implement practical actions to eliminate or reduce environmental problems. A reliable risk assessment particularly with view to organisms (vegetation as green fodder and hay production, grazing and wild animals) to avoid the transfer of Hg into the human food chain, requires an authentic determination of Hg fluxes and their dynamics since gaseous emissions from soil to atmosphere are an important pathway of Hg. However, reliable estimates of Hg fluxes from the highly polluted floodplain soils at the Elbe River and its tributaries, and its influencing factors are scarce. For this purpose, we have developed a new method to determine mercury emissions from soils at various sites. Our objectives were i) to quantify seasonal variations of total gaseous mercury (TGM) fluxes for floodplain soils at the Elbe River, ii) to provide insights into physico-chemical processes regulating these TGM fluxes, and iii) to quantify the impacts of the controlling factors soil temperature and soil water content on Hg volatilization from a typical contaminated floodplain soil within soil microcosm experiments under various controlled temperature and moisture conditions. Our study provides insight into TGM emissions from highly Hg-polluted floodplain soils in Germany and that those emissions are an underestimated problem. Current needs for reliable risk assessments, the induced implications for authorities, and future challenges will be discussed. The presented data will contribute to a better understanding of seasonal dynamics of Hg fluxes and its controlling factors. This presentation should be of large interest for a wide international audience, such as environmental scientists and managers, applied ecologists, and authorities.

Vanadium (V) is a naturally occurring trace element, but total concentrations in soils and sediments are also dependent on the parent material and might be influenced by anthropogenic activities (e.g., steel industry). Despite the fact that threshold values for V in soils and/or sediments exist in various European countries, in Belgium, V is not taken into account when the environmental quality of soils and sediments has to be evaluated, despite the existence of several (diffuse) sources for V. In the first part of the study, the occurrence of V alluvial soils in Belgium was compared with V concentrations in alluvial soils (floodplain soils) across Europe. By analysis of both the Belgian and European data, the relationship between physicochemical soil characteristics and total V concentrations was quantified and some areas polluted with V were detected. A regression equation, in which V concentrations in alluvial soils were expressed as a function of major element composition, was proposed for the Belgian and European data. Additionally, single extractions with CaCl2(0.01 mol L-1) and ammonium-EDTA (0.05 mol L-1) were used to estimate short- and long-term mobility of V in the alluvial soils.

Because of past mining activities, the floodplains of the River Geul are polluted with heavy metals. The continuous supply of fresh sediments during floods has caused the floodplain soils to exhibit large quality variations in time. By measurements of (137)Cs deposition rates in part of the floodplain area were determined at 0.4 to 2.7 cm yr(-1). Analysis of soil metal concentrations at various depths at 65 locations, revealed that the upper 40 cm of the soil profile deposited during the past 30-45 yr, exhibit the highest metal levels. The geostatistical interpolation technique kriging was used to map actual and past pollution patterns. It was shown that, as a result of variable deposition rates, the spatial correlation structure of soil metal concentrations becomes less clear with increasing depth/age. Kriged maps of average metal concentrations in the upper 100 cm of the soil profile provided the basis for the calculation of the mass storage of heavy metals.

Initial soil development in river floodplains influences soil properties and processes. In this study, suites of young floodplain soils sampled at three European rivers (Danube/Austria, Ebro/Spain and Elbe/Germany) were used to link soil development to the soils’ retention capacity for cadmium. Geochemichal fractionation of original and metal-spiked soils was conducted. Cadmium remained in weakly bound fractions in both original and spiked soils, representing an entirely different behaviour than observed for copper in an earlier study. The tendency of incorporation into more stable forms over time was only slightly expressed. Correlation analysis revealed the involvement of different sorption surfaces in soil, with no single soil constituent determining cadmium retention behaviour. Nevertheless, in the calcareous soils of the Danube floodplain, we found increased cadmium retention and decreased portions of desorbable cadmium with progressing soil development.

No Abstract.Discovery and INnovation Vol. 18 (4) 2006: pp. 288-294

Trace elements are potentially toxic to human life and the environment. Element toxicity depends on chemical associations in soils. Therefore, determining the chemical form of an element in soils is important to evaluate its mobility and bioavailability. Initial soil development in river floodplains influences soil properties, processes and therefore behavior of trace elements. In this study, three different floodplain soils sampled at three rivers (Nile/Egypt, Elbe/Germany and Penios/Greece) were used to link soil development and properties to the geochemical fractions and mobility of some trace elements. Sequential extraction was used to fractionate five trace elements (Cd, Cu, Ni, Pb and Zn) into five operationally defined groups: water soluble + exchangeable, carbonate, Fe-Mn oxide, organic, and residual. German soil showed the highest total concentration of the studied elements (except Ni). The Greek soil had the greatest amount of Ni. The residual fraction was the abundant pool for the studied elements examined in the Egyptian and Greek soils while the non-residual fraction was the dominant pool for all elements in the German soil. A significant amount (71- 94%) of all elements was present in German soil in the potentially available fraction: non-residual fraction, while the amount of this fraction ranged between 9 and 39 % in Greek soil and between 9 and 34 % in Egyptian soil. These suggest that the potential availability of the studied trace elements was extremely high in German soil compared to the Egyptian and Greek soil. In the German soil, most of the non-residual Cd, Ni and Zn were bounded with the Fe-Mn oxide fraction, while Cu and Pb distributed in the organic fraction. While in the Egyptian and Greek soils Fe-Mn oxide fraction was the abundant pool for the studied elements except for Cd, in which the exchangeable and the carbonate fractions had the greatest amount of Cd. Assuming that mobility and bioavailability of these elements are related to their solubility and geochemical forms, and that they decrease in the order of extraction sequence, the apparent mobility and potential bioavailability for the studied elements in the soils were: Cu > Cd > Ni ≥ Pb = Zn in Egyptian soil, Cd > Cu > Pb> Ni = Zn in Greek soil and Cd > Zn> Pb> Cu > Ni in German soil.

The possibility of interpreting waterlogged soils using scanner imagery of Voronezh and Smolensk oblasts and Krasnodar Kray from the Resurs-01 satellite is investigated. Reliable interpretation keys are described for waterlogged floodplain soils and hydromorphic soils of agricultural fields have reliable interpretation criteria.