Examination and presentation of element distribution in soil

Goal, Scope and Background  

The distribution of elements cannot only scatter widely in investigation areas, but also to a small scale in investigation fields. Chemometric methods are useful tools to describe the spatial distribution of the elements and are suitable to characterize the inhomogeneity in the soil. This knowledge can also be beneficial, among other things, for the creation of problem-adapted sampling strategies. The element distribution at one sampling point, the so-called microinhomogeneity considerably affects the representativeness of pollution assessment for a whole investigation area.     

Heavy metal pollution of the world largest antimony mine-affected agricultural soils in Hunan province (China)

Purpose  

The present work concerns the distribution of ten heavy metals (Sb, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in the surrounding agricultural soils of the world largest antimony (Sb) mine in China. The objective is to explore the degree and spatial distribution of heavy metal pollution of the Sb mine-affected agricultural soils. The presented data were compared with metal concentrations in soils from mining and smelting sites in China and other countries.     

Dynamic oxygen mapping in the root zone by fluorescence dye imaging combined with neutron radiography

Purpose  

The rooted zone of a soil, more precisely the rhizosphere, is a very dynamic system. Some of the key processes are water uptake and root respiration. We have developed a novel method for measuring the real-time distribution of water and oxygen concentration in the rhizosphere as a biogeochemical interface in soil. This enables understanding where and when roots are active in respect to root respiration and water uptake and how the soil responds to it.     

Potential of AFM–nanothermal analysis to study the microscale thermal characteristics in soils and natural organic matter (NOM)

Purpose  

This exploratory study evaluates the potential of nanothermal analysis (nTA) coupled with atomic force microscopy (AFM) of soil samples for understanding physicochemical processes in soil and for linking the nanospatial and microspatial distribution of thermal characteristics with the macroscopic properties of soil samples.     

Use of partition and redistribution indexes for heavy metal soil distribution after contamination with a multi-element solution

Purpose  

Tessier's sequential extraction method is usually used to study metal parting among different phases in soils. The main objective of this study was to determine the redistribution of trace metals which were added simultaneously to a sandy loam soil by use of the fractional distribution and reduced partition indexes and the risk of assessment code (RAC).     

BSAFs for freshwater fish and derivation of a sediment quality guideline for PCBs in the Rhone basin, France

Purpose  

Since 2005, freshwater fish contamination by polychlorobiphenyls (PCBs), polychlorodibenzodioxins, and polychlorodibenzofurans has been assessed in the Rhone River basin (France). A large database of surface sediment contamination by PCBs is also available, opening the way to the study of biota-to-sediment accumulation factor (BSAF) distribution throughout this basin. The ultimate goal of the study was to determine a sediment quality guideline (SQG) corresponding to the regulatory fish consumption limit.     

Forms and profile distribution of soil Fe in the Sanjiang Plain of Northeast China as affected by land uses

Purpose  

Since the mid-1950s, the wetlands in Sanjiang Plain of Northeast China have experienced greater changes in land use under which the mobility of soil Fe could be changed giving definite effects on the biomass production of adjacent regions. The aim of this work was to investigate the effects of land use change on the characteristics of soil Fe vertical distribution with a focus on evaluating the effects of cultivation on the soil Fe mobility in Sanjiang Plain.     

Simulation of polycyclic aromatic hydrocarbon remobilization in typical active regions of river system under hydrodynamic conditions

Purpose  

In an aquatic environment, hydrodynamic condition is a ubiquitous natural process, and the contaminated sediments will act as a potential pollution source once they are remobilized into the overlying water. In this study, remobilization behavior of polycyclic aromatic hydrocarbons (PAHs) under simulated hydrodynamic conditions was studied. Additionally, an adjusted prediction model with addictive consideration of surface properties was developed to exhibit the distribution of PAHs in hydrodynamic system.     

Using solid-phase microextraction to evaluate the role of different carbon matrices in the distribution of PAHs in sediment-porewater systems of the Baltic Sea

Purpose  

The speciation of polycyclic aromatic hydrocarbons (PAHs) in sediment-porewater systems affects both the chemical fate and bioavailability of these compounds. PAHs may be dissolved or sorbed to sediment particles or dissolved organic carbon (DOC). Furthermore, soot carbon has been shown to control the sorption of PAHs onto particles in natural waters. The present study investigates the distribution of individual PAHs among these three phases by examining sediments from the western Baltic Sea, focusing on a highly contaminated former dumping area and evaluating the importance of soot-carbon partitioning.     

Radionuclides and stable elements in the sediments of the Yesa Reservoir,Central Spanish Pyrenees

Purpose  

The sediments accumulated in the Yesa Reservoir (Central Spanish Pyrenees) have greatly decreased its water storage capacity and are a major threat to the sustainability of water resources in the region. This study examines the contents of radionuclides and stable elements in the reservoir sediments and relates their variations with the sediment composition and local sedimentary dynamics, particularly flood frequency and intensity, which are responsible for changes in the main supply and distribution of radionuclides in the basin.     

Fractionation of copper and cadmium and their binding with soil organic matter in a contaminated soil amended with organic materials

Purpose  

The contamination of agricultural soils by heavy metals is a worldwide problem. Organic amendments can be used for the immobilization and binding of heavy metal ions in soils by complexation, adsorption, and precipitation. A field trial was carried out to evaluate the influence of some low-cost organic materials such as rice straw (RS), green manure (GM), and pig manure (PM) on the distribution of Cu and Cd and the retention of these metals by organic matter fractions in heavy metal-polluted soils.     

The impact of a copper smelter on adjacent soil zinc and cadmium fractions and soil organic carbon

Purpose  

We investigated the chemical fractions of Zn, Cd and Cu in soils collected from positions at different distances from a copper smelter and studied the relationships between distribution patterns of Zn, Cd and Cu, fractions and soil organic carbon (SOC), especially “black carbon” (BC), in contaminated soils. The relationships between soil particle size and concentrations of Zn and Cd in contaminated soil were also examined.     

Modeling desorption kinetics of a persistent organic pollutant from field aged sediment using a bi-disperse particle size distribution

Purpose  

With the predicted climate change, it is expected that the chances of river flooding increase. During flood events, sediments will resuspend and when sediments are polluted, contaminants can be transferred to the surrounding water. In this paper we discuss a numerical intraparticle diffusion model that simulates desorption of dieldrin from a suspension of contaminated porous sediment particles with a well-characterized particle size distribution. The objective of this study was to understand the desorption rate (flux) of dieldrin from a suspension of field-aged sediment at different hydraulic retention times (HRT) of the aqueous phase and to elaborate the effect of particle-size distribution on mass transfer.     

Carbon and nitrogen pools in different aggregates of a Chinese Mollisol as influenced by long-term fertilization

Purpose  

It is known that soil organic matter (SOM) dynamics are sensitive to fertilizations, but it is different from soil to soil. It is unclear how the long-term applications of organic manure and mineral fertilizers impact the accumulation and distribution of soil organic carbon (SOC) and total nitrogen (TN) especially in soil aggregate fractions of Chinese Mollisols, which have been intensively cultivated for decades under maize monocropping and conventional tillage ways. Thereby, the research of this kind is very important for the sustainable use of agricultural land in China, where land resources are extremely limited for its huge population. The objectives of this study were to identify how the long-term fertilization treatments would affect the aggregate, SOC and TN distribution pattern in the Chinese Mollisol, and how soil aggregation contribute to the storage and stabilization process of SOC and TN.     

Effects of nitrogen fertilizer application rates on nitrate nitrogen distribution in saline soil in the Hai River Basin,China

Background and Objectives  

Soil nitrate nitrogen (NO₃ ⁻-N) accumulation is related closely to NO₃ ⁻ leaching, which is an important issue in groundwater pollution, especially in intensive agricultural areas with saline soils where volumes of water are used in irrigation to avoid salt accumulation in the root zone. However, in the saline environment in Hai River Basin, China, the importance of detailed research into NO₃ ⁻-N distribution in the root zone has not been adequately recognized. Considering the impacts of eco-environmental system N and crop production, the present study aimed at contributing to an understanding of the effects of N application rate on soil NO₃ ⁻-N distribution, NO₃ ⁻-N residue, N loss, and maize (Zea mays L.) yield in this region.     

Effects of endophytic Bacillus spp. on accumulation and distribution of iron in the shoots of lowland rice grown under iron toxic conditions

Background

The tolerance of plants against abiotic stresses can be greatly influenced by their interaction with microbes. In lowland rice (Oryza sativa) production, the iron toxicity of the soils constitutes a major constraint. Although there are tolerant cultivars, the mechanisms underlying the tolerance against excess iron are not fully understood. Even less is known about the role of microbes in the response to iron toxicity.

Aim

In the study presented here, the effects of different Bacillus isolates on the accumulation and distribution of iron within the shoots of different rice cultivars grown under iron toxicity were analyzed.

Methods

Three lowland rice cultivars with contrasting tolerance to iron toxicity (IR31785-58-1-2-3-3, Sahel 108, Suakoko 8) were inoculated with three Bacillus isolates (two B. pumilus and one B. megaterium) and, after 1 week, exposed to excess iron (1,000 ppm) for 8 days. Tolerance was evaluated by leaf symptom scoring.

Results

Bacterial inoculation mitigated leaf symptoms in the sensitive cultivar IR31785-58-1-2-3-3 despite no significant differences in shoot iron concentration between inoculated and noninoculated plants. In the tolerant excluder cultivar, Suakoko 8, leaf symptoms were exacerbated when inoculated with B. pumilus Ni9MO12. While the total shoot Fe concentration was not affected in this bacteria × cultivar combination, the distribution of iron within the shoot was clearly disturbed. Tolerance to iron toxicity of the tolerant includer cultivar, Sahel 108, was not affected by Bacillus inoculation.

Conclusion

In conclusion, our results show that Bacillus inoculation can affect the tolerance of lowland rice to iron toxicity and that the effects strongly depend on the bacteria × cultivar combination.     

Enhancing maize grain yield under salt-affected field conditions using salt-resistant maize hybrids and higher planting density

Background

In arid and semiarid countries, grain yield of maize is increasingly impaired by soil salinity. Beside soil amelioration, the development of salt-resistant cultivars is a possibility to enhance crop yield on salt-affected soils.

Aims

This study aimed at testing yield performance in the field of salt-resistant maize hybrids on a salt-affected soil. In addition, planting density was optimized under the saline conditions.

Methods

Four salt-resistant maize hybrids (Zea mays L. SR-05, SR-12, SR-15, and SR-16) were grown under control (EC = 2.0–2.5 dS m⁻¹) and saline (EC = 10.0–12.0 dS m⁻¹) field conditions and compared to the salt-sensitive maize cv. Pioneer-3906. Planting density (5, 8, or 11 plants m⁻²) was optimized for saline soil conditions for SR-12 and the local hybrid EV-78.

Results

Yield of Pioneer-3906 was significantly reduced under salinity because of inhibited kernel setting, whereas the SR hybrids showed no decrease in grain yield. Based on grain yield, the optimum planting density was 8 plants m⁻² with no further increase with 11 plants m⁻². In contrast to SR-12, for cv. EV-78 no increase of harvest index with 8 relative to 5 plants m⁻² was observed.

Conclusions

Vegetative growth of Pioneer-3906 and the SR hybrids was decreased due to Phase-I effects but neither due to water deficiency nor ion toxicity. The experiment corroborated the salt resistance of the SR hybrids under field conditions. Under saline conditions, optimum planting density of salt-resistant cultivars may be higher than under nonsaline conditions when sufficient water supply by artificial irrigation is guaranteed.     

Compost application affects metal uptake in plants grown in urban garden soils and potential human health risk

Purpose  

This study explores the effect of varying organic matter content on the potential human health risk of consuming vegetables grown in urban garden soils.     

An appraisal of the contemporary sediment yield in the Ebro Basin

Purpose  

The main aim of this work is to provide a comprehensive estimation of the sediment yield of the Ebro Basin (NE Iberian Peninsula) in the twentieth century.     

Development of sediment quality criteria in Norway

Introduction  

A Norwegian system for classification of environmental quality of contaminated marine sediments has been in force since 1997 and was revised in 2007.