Angel Faz Cano

BASELINE STUDIES OF THE CLAY MINERALS SOCIETY SOURCE CLAYS: CHEMICAL ANALYSES OF MAJOR ELEMENTS

Chemical analysis is an essential step to establish the nature of minerals (Newman, 1987). The techniques used in rock and mineral analyses are generally valid for the analyses of clays. Additional information from other analytical techniques, which are mentioned here, is needed for accurate interpretation of the chemical analysis results of major elements (Gabis, 1979). In traditional chemical analyses, the aim is to obtain accurate analyses for all elements present in the sample, in such a way that the sum of elements expressed as oxides, including hydration and structural water, approaches the sample weight as closely as possible. The following elements are essential for the calculation of structural formulae of most clay minerals and silicates: Si, Al, Fe3+, Fe2+, Mg, Ti, Mn (in special cases), P, Ca, Na, K and H2O evolved below 105°C (H2O+) and between 105–1000°C (H2O+). For some minerals, additional determinations, such as for F and Li, may be needed for the calculation of the composition of clay minerals. Methods used to determine the chemical composition, for both major and minor elements, are described elsewhere (Jackson, 1979; Lim and Jackson, 1982; Laird et al., 1989; Amonette and Zelazny, 1994). For minor or trace elements of the Source Clays, see Elzea Kogel and Lewis (2001). Despite the progress made in science, and the increased accuracy which can be obtained from very sophisticated instruments, total …

Biomagnetic monitoring of heavy metals contamination in deposited atmospheric dust, a case study from Isfahan, Iran.

Tree leaves are considered as one of the best biogenic dust collectors due to their ability to trap and retain particulate matter on their surfaces. In this study, the magnetic susceptibility (MS) and the concentration of selected heavy metals of plane tree (Platanus orientalis L.) leaves and deposited atmospheric dust, sampled by an indirect and a direct method, respectively, were determined to investigate the relationships between leaf magnetic parameters and the concentration of heavy metals in deposited atmospheric dust. The objective was to develop a biomagnetic method as an alternative to the common ones used for determining atmospheric heavy metal contaminations. Plane tree leaves were monthly sampled on the 19th of May to November, 2012 (T1-T7), for seven months from 21 different sites in the city of Isfahan, central Iran. Deposited atmospheric dust samples were also collected using flat glass surfaces from the same sites on the same dates, except for T1. MS (χlf, χhf) values in washed (WL) and unwashed leaves (UL) as well as Cu, Fe, Mn, Ni, Pb, and Zn concentrations in UL and deposited atmospheric dust samples were determined. The results showed that the MS content with a biogenic source was low with almost no significant change during the sampling period, while an increasing trend was observed in the MS content of UL samples due to the deposition of heavy metals and magnetic particles on leaf surfaces throughout the plant growth. The latter type of MS content could be reduced through washing off by rain. Most heavy metals examined, as well as the Tomlinson pollution load index (PLI) in UL, showed statistically significant correlations with MS values. The correlation between heavy metals content in atmospheric dust deposited on glass surfaces and leaf MS values was significant for Cu, Fe, Pb, and Zn. Moreover, the similarity observed between the spatial distribution maps of leaf MS and deposited atmospheric dust PLI provided convincing evidence regarding the suitability of the biomagnetic approach as a relatively rapid and inexpensive method for identifying highly polluted urban areas with selected heavy metals, especially those subjected to anthropogenic and other traffic related sources.

2-D Electrical Resistivity Imaging to Assess Slurry Pond Subsoil Pollution in the Southeastern Region of Murcia, Spain

About 2,341 pig farms generate large amounts of slurry in the southeastern Region of Murcia, Spain. Given the nature of the pig slurry as well as its amount produced in livestock, it has become a matter of growing environmental concern. The control of slurry ponds is now a top priority concern to create a safer environment, especially for agricultural production. This study reports the results of a much wider and comprehensive project carried out to collect reliable data on the behavior of slurry, soil, and the infiltration of slurry ponds under semiarid climate. The two-dimensional (2-D) electrical resistivity imaging (ERI) technique was used to qualitatively evaluate the natural permeability of the soils and depth that slurry had reached. The results obtained have shown that ERI is a useful tool in mapping the infiltration, as well as monitoring seasonal changes in the pollutant plume underneath the slurry ponds.

Soil fertility status and nutrients provided to spring barley (Hordeum distichon L.) by pig slurry

Nutrient recycling using pig slurry is a common agricultural practice to manage the ever-increasing amounts of wastes from the pig industry. This study was conducted in the southeast of Spain to quantify the enrichments in major (N, P, K, Mg) and minor (Zn, Fe, Cu, and Mn) nutrients in soils amended with D1-170 kg N ha-1 (European Union legislated dose) or D2-340 kg N ha-1, and understand the influence of pig slurry on yield and nutrient uptake in two crop seasons of spring barley (Hordeum distichon L.) Compared to control, D2 increased NO3--N by 11.4X to 109 mg kg-1, Olsen-P by 6.9X to 423 mg kg-1, exchange K (2.5X to 1.6 cmol+ kg-1), Mg (1.7X to 1.8 cmol+ kg-1), diethylene-triamine pentaacetic acid (DTPA)-Zn (94X to 18.2 mg kg-1), and Fe (2X to 11.3 mg kg-1). Available NO3--N, Olsen-P, and DTPA-Zn have the best correlations with crop yield and nutrient uptake. These results indicate that the assessment of soil fertility status at 1-mo after pig slurry addition provides a good indicator for potential yield and uptake of barley. However, it is suggested that leachates should be monitored to effectively manage potential releases of nitrate and phosphate into the environment.

What We Know About the Saga of Land Degradation and How to Deal with It

The 5th International Conference on Land Degradation held at the Mediterranean Agronomic Institute of Bari, Italy in September 2008 brought together some 100 people from 37 countries worldwide. A number of international organisations, like FAO, IAEA, EC, and CIHEAM were also present. The conference was split into 8 sessions where 83 papers (43 oral) were presented. In total 235 abstracts were received. The main outcome was that the fight against land degradation and desertification could be successful if the right policy instruments are put in place and most importantly when local people are both authors and actors of the development process. Moreover, soil conservation and restoration should be one component of an integrated ecosystem management strategy that should include also water, biodiversity, livelihoods and human impacts on ecosystems. There are numerous positive results when dealing with land degradation worldwide. They should be used to emphasise the urgent needs for further actions to accelerate and scale up progress and not to induce complacency. Improved land resources management measures should build on scientific evidence, local innovation and knowledge and be locally tested and validated before being applied at larger scale. Natural resource base conservation should continue to be a priority for national governments and international organisations but Africa requires particular attention. The recent financial, economic and food global crisis should not overshadow the urgent needs to deal with natural resource management and conservation and mitigate climate change impacts.

Using visible and near infrared spectroscopy to estimate carbonates and gypsum in soils in arid and subhumid regions of Isfahan, Iran

Soils in arid and semi-arid regions are strongly affected by the accumulation of carbonates, gypsum and other, more soluble, salts. Carbonates and gypsum both have a considerable influence on soil properties, especially the chemical properties of the soil solution. The development of reliable, fast and inexpensive methods to quantify the amounts of carbonates and gypsum in soil is therefore important. Visible and near infrared (vis-NIR) spectroscopy is a non-destructive, rapid and cheap method for measuring several soil properties simultaneously. However, research on vis-NIR spectroscopy in quantifying carbonates and gypsum is limited. Therefore, this study evaluated the efficiency of vis-NIR spectroscopy in quantifying carbonates and gypsum in surface soils using partial least-squares regression (PLSR) compared with standard laboratory methods and compared PLSR with a feature-specific method using continuum removal (CR). Carbonates and gypsum in a total of 251 sieved and air-dried topsoil samples from Isfahan Province in central Iran were measured by standard laboratory methods and vis-NIR spectroscopy (350–2500 nm wavelength range). In parallel, PLSR and the feature- specific method based on CR spectra were used to predict carbonates and gypsum. The PLSR model efficiency (E) for carbonates and gypsum in the validation set was 0.52 and 0.80, respectively. The PLSR model resulted in better predictions than the feature-specific method for both soil properties. Because of the unique absorption features of gypsum, which did not overlap with other soil properties, predictions of gypsum resulted in higher E values and lower errors than predictions of carbonates.

Phytostabilization of Lead-Polluted Sites by Native Plants

The Cartagena–La Union Mining District in southeast Spain is an example of a lead-polluted site that exhibits a wide range of environmental problems. Risks associated with the high concentrations of heavy metals present, especially lead, and their large affected surface areas make such sites excellent candidates for phytostabilization. However, for the Cartagena–La Union Mining District, there were several factors, including the chemical and physical properties of the soil and the warm, semiarid climate, that made revegetation a very difficult task.

Effect of Pig Slurry Application on Soil Organic Carbon

The use of pig slurry (PS) as a fertilizer has been practised for a long time. Direct application to soils at an adequate level influences the soil organic matter and quality positively, a critical component of soil fertility and productivity. Organic manure is considered as a source of slow-release nitrogen (N) fertilizer. High initial applications to build up the organic pool and cut back in subsequent years would be appropriate. In supplying the nutrient requirements, the amount of manure applied can be calculated based on the rate of N applied and the rate of organic N mineralization in the application season. There are many factors to be considered when attempting to assess the overall net impact of a management practice on soil quality and productivity. Additions of manure to soils at agronomic rates to match crop nutrient requirements are expected to have a positive impact on soil quality and productivity. Salinity impacts and overloading of both functional and non-functional elements can negate these benefits when manure is overapplied or applied to soils with limitations in drainage and buffering capabilities.

The chelating effect of citric acid, oxalic acid, amino acids and Pseudomonas fluorescens bacteria on phytoremediation of Cu, Zn, and Cr from soil using Suaeda vera

ABSTRACT Phytoextraction is a green technique for the removal of soil contaminants by plants uptake with the subsequent elimination of the generated biomass. The halophytic plant Suaeda vera Forssk. ex J.F.Gmel. is an native Mediterranean species able to tolerate and accumulate salts and heavy metals in their tissues. The objective of this study was to explore the potential use of S. vera for soil metal phytoextraction and to assess the impact of different chelating agents such as natural organic acids (oxalic acid [OA], citric acid [CA]), amino acids (AA) and Pseudomonas fluorescens bacteria (PFB) on the metal uptake and translocation. After 12 months, the highest accumulation of Cu was observed in the root/stem of PFB plots (17.62/8.19 mg/kg), in the root/stem of CA plots for Zn (31.16/23.52 mg/kg) and in the root of OA plots for Cr (10.53 mg/kg). The highest accumulation of metals occurred in the roots (27.33–50.76 mg/kg). Zn was the metal that accumulated at the highest rates in most cases. The phytoextraction percentages were higher for Cu and Zn (∼2%) with respect to Cr (∼1%). The percentages of metal removal from soil indicate the need to monitor soil properties, to recognize the influence of each treatment and to increase the concentration of bioavailable metals by the use of agricultural management practices aimed at promoting plant growth.

Distribution of palygorskite in Cretaceous and Tertiary sediments and the associated soils in southern Iran

Little is known about the distribution and origins of palygorskite in soils developed on Tertiary and Cretaceous rocks and sediments and the associated soils in such areas as Fars Province, southern Iran, or the other Middle Eastern countries. The present study pursued the twofold objective of (1) identifying the distribution and sources of palygorskite in the soils developed on the above sediments and (2) determining the major soil properties influencing palygorskite distribution. Eight soil profiles developed on Cretaceous and Tertiary sediments and their parent materials were sampled and studied using XRD, SEM, and EDX analyses. The results revealed that most of the palygorskite was inherited from the respective parent materials although some seemed to be the product of neoformation pathways as a result of gypsum and calcite precipitation. Principal component analysis revealed that the most significant factors affecting the distribution and genesis of palygorskite in the soils developed on Cretaceous sediments are electrical conductivity (EC), clay, soluble Si, organic C, calcium carbonate equivalent (CCE), and smectite while those for Tertiary parent material-derived soils are the amounts of gypsum, illite, organic C, and CCE. Multiple regression analysis suggested smectite, pH, gypsum, and EC in the Cretaceous samples and the values of gypsum and soluble Ca and Si in the Tertiary soils as indicators to be used for predicting palygorskite content.