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Introduction: Up to 40 % of the patients undergo breast cancer surgery suffer or have suffered secondary lymphedema. The deterioration of the functionality and its effect on the activities of daily living (AVD) make the studies necessary to provide a better quality of life and a more effective treatment. Objective: To evaluate the possible effectiveness in the application of the kinesio taping as an alternative to the multilayered bandage in the treatment of the secondary lymphedema in breast cancer patients. Material and method: The following databases were searched: PubMed, Web of Science, ScienceDirect, Cochrane, Scopus and PEDro including only clinical controlled trials in english, french and spanish and those studies that were not treating the effectiveness of the kinesio taping as a specific form in replacement of multilayered bandage were excluded. Results: A total of 132 studies were found in the consulted databases. Five randomized cinical trials were included in this review, after checking the inclusion criteria. Used protocols, the criteria of patients' inclusion and exclusion, the type of design of its studies, the methods of evaluation used, the interventions carried out and the results ibtained were analyzed. Conclusions: There is currently no evidence of the possible replacement of the multilayered bandage for kinesio taping due to the disparity of conclusions that we extracted from the clinical trials analyzed. It is suggested to carry out more exhaustive studies that would allow to verify its possible replacement. [ABSTRACT FROM AUTHOR]

Fluxes of acidity and contaminants from acid mine drainage (AMD) sources to the receiving surface water bodies were studied in a mining-impacted watershed (Meca River, SW Spain) using a novel methodology based on the joint application of EMMA and MIX codes. The application of EMMA and elemental ratios allowed delimiting the end-members responsible for water quality variations at a catchment scale. The further application of MIX quantified the significant impact of AMD on the river quality; less than 10% of AMD relative contribution is enough to maintain acidic conditions during most of the year. The mixing model also provided information about the element mobility, distinguishing those elements with a quasi-conservative behavior (e.g., Cu, Zn, Al, Co or Ni) from those affected by mineral precipitation/dissolution (e.g., K, Si, Na, Sr, Ca, Fe, Pb, or As). Floods are the main driver of dissolved and, mainly particulate, contaminants in the catchment. Thus, the first rainfall events in November only accounted for 19% of the annual Meca flow but yielded between 26 and 43% of the net acidity and dissolved metal loads (mainly, Fe, As and Pb). Concerning particulate transport, around 332 tons of particulate Fe, 49 tons of Al, 0.79 tons of As and 0.37 tons of Pb were recorded during these first floods. The particulate As concentration can be up to 34 times higher than the dissolved one during floods and between 2 and 4 times higher for Fe, Pb and Cr. This integrated modeling approach could be a promising and useful tool to face future restoration plans in derelict mines worldwide. This approach would allow prioritizing remedial measures, achieving an environmental and cost-effective restoration of degraded areas. [ABSTRACT FROM AUTHOR]

Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO 4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in derelict mines worldwide. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fruiting occurred on cladodes with fresh and dry weights surpassing 144g and 14.4g, respectively. [•] One-year-old cladodes with ≈144 to ≈964g of fresh weight produced 6 fruits or even more. [•] Maximum number of fruits of ≈15 could be strongly ascribable to ≈50g of cladode dry weight. [ABSTRACT FROM AUTHOR]

Abstract: A 2month long column study was conducted to evaluate the mobility of heavy metals eluting from Technosols constituted from sewage sludges (aerobic or anaerobic) (as controls) or a mixture of different types of sewage sludges with green foundry sand (FS) or/and Linz–Donowitz slag (LD). The organic and inorganic wastes were mixed at a ratio of 56:44 (w/w). The mixtures and the controls were moistened to field capacity before adding them to the polypropylene columns (4.5cm wide and 14cm long). During the 8-week experimental period, the columns were watered, twice a week, with 100mL of deionised water. The concentrations of heavy metals (Cu, Zn, Ni, Pb, Cd, and Cr) in the leachates were determined periodically. The concentrations of all the heavy metals were generally higher in the leachates from the Technosols containing anaerobic sewage sludge as a component. The concentration of Cu was strongly dependent on pH and was significantly higher (P <0.05) in the most alkaline leachates (pH>10) than in the other leachates. More Zn was mobilized in the most acidic leachates (pH<6) than in other leachates. The concentration of Ni in 80% of the leachates exceeded the EU drinking water limit for Ni (0.02mgL−1). The concentrations of Pb were lower in the Technosols containing FS. The concentrations of Cd in the leachates from Technosols containing the conditioners were relatively high, while concentrations of Cr were higher in the controls. As far as the potential toxicity of heavy metals is concerned, the combination of aerobic sludge, inorganic conditioners able to buffer the pH to around neutrality, and reactive aluminosilicates, can be regarded as suitable choice for formulating Technosols from wastes. [Copyright &y& Elsevier]

The preparation of tailor-made Technosols from wastes may be a novel and prospective option for the re-use of wastes and restoration of degraded areas. A two-month study with pilot columns was conducted to evaluate the influence of the acid buffering capacity of different Technosols on the chemistry of their leachates. The Technosols were made from mixtures of organic and inorganic wastes at a ratio of 56:44 (w/w). The organic components used were an anaerobic (AN) and an aerobic (AE) sewage sludge. The inorganic wastes used – referred to as “conditioners” – were Linz-Donowitz slag (LD) and foundry sand (FS). A mixture of the two conditioners at a ratio of 50:50 (w/w) was made to provide a third type of conditioner (LD+FS). Controls consisted of columns filled with organic waste only (either AN or AE sludges). Changes in pH, electrical conductivity, concentrations of major ions and dissolved organic carbon in the leachates were evaluated periodically. The main processes determining the pH of the systems were nitrification and leaching, but organic matter decomposition and carbonation may also have had an influence. Nitrification was strongly retarded in the AN sludge (attributed to the probable absence of nitrifiers in this waste after the AN wastewater treatment) and was impeded in those mixtures in which LD was used as a component (due to the liming effect). Final pH values ranged from 5.0 and 5.4 (in AE and AE+FS, respectively) to 11.1 (in AN+LD). The pH of the other mixtures finally ranged between 7 and 8. In formulating mixtures of wastes, their acid buffering capacity should be taken into account in addition to the nutrient contents and the limits of contaminants established by local regulations. [Copyright &y& Elsevier]

Abstract: Calculations of critical loads of acidity within Europe have shown Galicia to be one of the regions in Spain with the highest risk of soil acidification by deposition of atmospheric pollutants. We used the simple mass balance method (SMB) to derive critical loads of sulphur and nitrogen for forest soils in Galicia using available site-specific information. Exceedance of acidic deposition was calculated using the deposition levels of N and S registered in 2001. Most forest ecosystems analysed can support acid loads of more than 2000 eq N ha−1 year−1. The lowest critical loads of acidity (1483 eq ha−1 year−1) occurred in coniferous forest stands growing on shallow soils developed on slates, in the interior zone. The highest critical load values (9386 eq ha−1 year−1) were observed in coniferous stands in zones with elevated precipitation rates, in the littoral area. The critical load for acidity was exceeded in 5% of the forest soils. Such exceedances were mainly caused by deposition of nitrogen compounds. The contribution of sulphur deposition to acid exceedance was important in the surroundings of the city of A Coruña. Analysis of rainfall bulk composition revealed that N deposition in Galicia was mainly due to ammonium emissions, probably derived from agricultural and cattle breeding activities. [Copyright &y& Elsevier]

This paper explores the possibility of using wastes (i.e. solid phosphogypsum (PG), process waters and edge outflows) generated by a fertilizer plant in SW Spain as a source of elements of economic interest, estimating the available metal reserves and discussing the technological and economic pros and cons of this potential source of raw materials. In general, elements of economic interest are found in these wastes below of the grades commonly reported in conventional deposits. However, the huge tonnage of wastes stockpiled constitutes a significant secondary source of elements. Around 30,400 t of B, 28,000 t of rare earth elements (REE), 1800 t of U, 1400 t of Cr, 1300 t of V and lesser amounts of other elements of economic interest (e.g. Cu, Ni, Sc and Ga) are enclosed in the solid PG while lower amounts are found in process waters (e.g. 1360 t of Zn, 760 t of V, 630 t of U and Cr, 225 t of Cu, 160 t of Ni, 190 t of REE). Considering the market metal prices, the reserves contained in the Huelva PG stack have a potential value of around 8937 million USD, which mainly correspond to PG (97% of total value). The recovery of these elements is technically feasible, although intense research in refining processes is needed in order to increase the purity of the final product. The results of this study could be of interest in other PG stacks worldwide to provide more sustainable and cost-effective management of these wastes. [ABSTRACT FROM AUTHOR]

Compared with pit lakes originated by coal mining, little is known about in-lake neutralization processes in pit lakes from sulfide ore mining in hard rock substrates, which are typically very deep and acidic and receive low carbon (C) inputs and groundwater flows. Physicochemical processes in water and sediments from a pit lake (San Telmo, 130 m deep) in the Iberian Pyrite Belt were investigated. San Telmo is a meromictic and highly acidic (pH 2.8) pit lake due to pH buffering by precipitation of Fe(III) minerals (schwertmannite and jarosite). The sediments have a low abundance of C (below 0.60%) and iron minerals (below 0.12%) compared to most coal-mining pit lakes. In San Telmo sediments, iron reduction and sulfide oxidation may be thermodynamically favored due to low pH values in pore waters (below 3.8) and the presence of reactive iron. Although schwertmannite is the main ferric mineral precipitating in the water column, mineralogical analyses reveal a low abundance of schwertmannite in the sediment. This may be due to the preferential use of this mineral in reduction reactions mediated by bacteria, together with a low replenishment rate of the schwertmannite pool in the sediment. The transformation of reactive iron (schwertmannite and jarosite) into goethite may limit sulfate reduction, promoting acidic conditions in the sediment. As long as the acid mine drainage continues to discharge into the lake, the pH buffering exerted by ferric minerals in the sediments will limit the neutralization of the pH by sulfate reduction. [ABSTRACT FROM AUTHOR]

Gossan wastes represent one of the most hazardous mine wastes in several mining areas from the Iberian Pyrite Belt. Phytostabilisation of mine wastes with Cistus ladanifer L. could be a good option, but its growth and germination are impaired by substrata conditions. To overcome these limitations, application of organic and inorganic amendments may speed up the growth of C. ladanifer while improving the mine wastes. This study evaluated the simultaneous influence of different application rates of amendments and growth of C. ladanifer on chemical and biological properties of gossan wastes. Amendments used were mixtures (30, 75, 150 Mg/ha, 1:1:1) of rockwool, agriculture wastes and wastes from liquor distillation of Arbutus unedo L. fruits. A microcosm assay with four treatments was carried out (control and three amended treatments) under controlled conditions in a greenhouse during 505 days. Cistus ladanifer was sown in half of the pots from each treatment while the remainder was left bare. Gossan wastes had large total concentrations of several elements (g/kg; Al: 24.8, As: 3.03, Cu: 0.23, Pb; 9.21) whereas the available concentrations of these elements were small (< 5.7 % of total). The amendments applied (in particular at 75 and 150 Mg/ha) improved the structure and increased the water-holding capacity, pH and nutrient concentrations in the available fraction of the gossan materials. They also led to increases in dehydrogenase and β-glucosidase activities and in plant growth (plant cover, plant height, length of young leaves, fresh biomass). In addition, plants from amended treatments presented lower concentrations of hazardous elements in shoots than plants from unamended control. The presence of the plant did not increase the available concentrations of hazardous elements in wastes, except for As when 150 Mg/ha of amendments was applied. Phytostabilisation with C. ladanifer using a Technosol, resulting from the application of the studied amendments at 75 and 150 Mg/ha to gossan materials, seems a promising solution for rehabilitation of this type of mine wastes. [ABSTRACT FROM AUTHOR]

Bacterial and archaeal community structures and diversity of three different sedimentary environments (BH1A, BH2A and BH3A) in the acid pit lake of a chalcopyrite mine at Touro (Spain) were determined by 16S rRNA gene PCR-DGGE and sequencing of clone libraries. DGGE of bacterial and archaeal amplicons showed that the sediments harbor different communities. Bacterial 16S rRNA gene sequences were assigned to Acidobacteria, Actinobacteria, Cyanobacteria, Planctomycetes, Proteobacteria, Chloroflexi and uncultured bacteria, after clustering into 42 operational taxonomic units (OTUs). OTU 2 represented approximately 37, 42 and 37 % of all sequences from sediments BH1A, BH2A and BH3A, respectively, and was phylogenetically related to uncultured Chloroflexi. Remaining OTUs were phylogenetically related to heterotrophic bacteria, including representatives of Ferrithrix and Acidobacterium genera. Archaeal 16S rRNA gene sequences were clustered into 54 OTUs. Most of the sequences from the BH1A sediment were assigned to Euryarchaeota, whereas those from BH2A sediment were assigned to Crenarchaeota. The majority of the sequences from BH3A sediment were assigned to unclassified Archaea, and showed similarities to uncultured and unclassified environmental clones. No sequences related to Acidithiobacillus and Leptospirillum, commonly associated with acid mine drainage, were detected in this study. [ABSTRACT FROM AUTHOR]

Abstract: Persistent organic pollutants (POPs) are within the most dangerous pollutants released into the environment by human activities. Due to their resistance to degradation (chemical, biological or photolytic), it is critical to assess the fate and environmental hazards of the exchange of POPs between different environmental media. System Dynamics enables to represent complex systems and analyze their dynamic behavior. It provides a highly visual representation of the structure of the system and the existing relationships between the several parameters and variables, facilitating the understanding of the behavior of the system. In the present study the fate of γ-hexachlorocyclohexane (lindane) in a contaminated soil was modeled using the Vensim® simulation software. Results show a gradual decrease in the lindane content in the soil during a simulation period of 10years. The most important route affecting the concentrations of the contaminant was the biochemical degradation, followed by infiltration and hydrodynamic dispersion. The model appeared to be highly sensitive to the half-life of the pollutant, which value depends on environmental conditions and directly affects the biochemical degradation. [Copyright &y& Elsevier]

Abstract: The aim of the present study was to select candidate plant species for phytoremediation of soils contaminated with hexachlorocyclohexane (HCH). For this purpose, an experiment was carried out under controlled conditions of germination and growth, with nine plant species of economic and/or agricultural interest, in a soil contaminated with a heterogeneous mixture (at eight different levels of contamination) of the main HCH isomers (α-, β-, γ- and δ-HCH). The results revealed differences in the plant responses to the control soil and the soils containing HCH. Germination was not as strongly affected as other parameters such as the rate of germination and seedling vigour. In general, all of the species displayed signs of stress in response to the presence of HCH, although to different degrees. Some of the species used in the experiment (Hordeum vulgare L., Brassica sp., Phaseoulus vulgaris L.) were capable of mitigating the negative effects of HCH, and displayed a certain degree of resistance, as their biomass production was not greatly affected by the contaminant. These (tolerant) plants therefore appear to be ideal for phytoremediation purposes. [Copyright &y& Elsevier]

The organic matter (OM) of soils with andic properties has long been considered highly stable because of the presence of Al–humus complexes and sorption of organic ligands onto amorphous compounds. In this study, we characterized soils under different land use regimes located within an amphibolitic massif close to Santiago de Compostela (Spain), where soils with andic properties are present. Slash and burn agriculture was a common practice in the area until the second half of the 20th century. Thereafter, modern agriculture was progressively introduced into the area (AGR soils), and the rest of the land was either reforested or abandoned (FOR soils). We found that the mean organic C content of AGR soils (48.7 g kg−1) was∼ 50% that of FOR soils (94.2 g kg−1). Mean soil pH was significantly greater (P < 0.05) in the AGR than in the FOR soils (4.95 compared with 4.63), which is attributed to liming and Ca-phosphate fertilization of the former. Mean concentrations of the Al forms studied (extractable with CuCl2, sodium pyrophosphate, ammonium oxalate, or NaOH) were significantly smaller (P < 0.01) in AGR (1.4, 4.9, 9.3, 11.0 g kg−1, respectively) than in FOR soils (3.9, 10.2, 16.5, 17.9 g kg−1, respectively). The results show the vulnerability of the OM and Al–humus complexes in these soils to modern agricultural practices, which has led to the attenuation– and in some cases even the disappearance– of andic soil properties in a relatively short time (< 30 years) following changes in land use/management. We propose the inclusion of the formative element‘andic’ in the criteria for the definition of Umbrisol subunits; this would avoid the abrupt discontinuity observed in the current World Reference Base classification. [ABSTRACT FROM AUTHOR]

Examines the phosphate and sulfate sorption capacities of several Spanish Spodosols with albic horizon. Molar ratios of organic carbon; Characteristics of soil used in the study; Identification of the infrared spectra of untreated soil samples from spodic horizons.

Abstract We have investigated the effect of supercritical drying (SD) on the porosity and the BET-N 2 specific surface area (SSA) of five allophane-rich and three non-allophanic topsoils. The contribution of organic matter (OM) and short-range ordered (SRO) constituents to the nanoscale porosity (<100 nm size) and SSA was also evaluated following chemical treatments to oxidise OM and then remove the SRO phase. The average pore volume and SSA of the soils, measured after SD, are greater than the values obtained after air drying. For soils that are rich in SRO constituents, oxidation of OM leads to an increase in SSA. This observation is attributed to the unblocking of pore necks previously covered by OM, while the subsequent removal of SRO constituents causes a sharp decrease in SSA. The SRO constituents containing oxalate-extractable Al, are the major contributors to the SSA of the inorganic fraction. Besides confirming that SD can help preserve the nanoscale porosity of allophane-rich soils, the results highlight the contribution of SRO constituents to the SSA of soils and their ability to accumulate OM. Highlights • Controlled supercritical drying (SD) of soils facilitates dehydration while preserving structure. • In allophane-rich soils, SD preserved mesoporosity and specific surface area (SSA). • SSA increased after removal of organic matter uncovering mineral surfaces. • Removal of short-range ordered constituents decreased pore volume and SSA. [ABSTRACT FROM AUTHOR]

Objectives: Good syndrome is a rare condition in which a thymoma is associated with hypogammaglobulinemia. It is also characterized by low or absent B-cells, CD4+ T-cell lymphopenia, inverted CD4/CD8+ T-cell relation, and repeated bacterial, viral, and fungal infections, as well as with various autoimmune disorders. Case report: We report the case of a 62-year-old female patient who after resection of a thymoma developed constipation and recurrent lower respiratory and urinary tract infections. She underwent left hemicolectomy as well as symptomatic and antibiotic treatment. Two years later the patient develops refractory anemia; a bone marrow biopsy shows hypo-cellularity and no red cell precursors with negative CD 71 staining. The diagnosis of pure red cell precursor aplasia (PRCA) is made. Recurrent bacterial infections of the respiratory and urinary tracts continue, and therefore treatment with G and A immunoglobulins starts. Finally, the absence of B lymphocytes and inversion of CD4/CD8 relation confirms the diagnosis of Good syndrome associated with PRCA. Discussion: The discovery of Good Syndrome and PRCA after the resection of a thymoma, as seen in the current case, is very unusual. This case illustrates both the rareness presentation of Good syndrome with PRCA and the persistent infections seen in these patients. Early recognition of these entities results in lower mortality and morbidity. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the effects of plants on the underlying substrate and the possible environmental implications of such effects in an extreme environment. For this purpose, we sampled the rhizosphere soil of Bolax gummifera , which is one of the most characteristic vascular plants in the Martial Mountains (Tierra del Fuego, Argentina) where plant cover is typically sparse. Superficial (0–5 cm, Rh5) and subsuperficial (5–15 cm, Rh15) samples of B. gummifera rhizosphere and bulk soil were collected from a small homogeneous area, and the following parameters were analyzed: particle size, pH, total organic carbon (TOC), total nitrogen (TN), total Fe (TFe), Fe and Al associated with organic matter (soluble in sodium pyrophosphate, C pyro ), amorphous Fe oxyhydroxides (extracted with ammonium oxalate, Fe oxa ), crystalline Fe oxyhydroxides (extracted with sodium dithionite, Fe dit ), bioavailable plant nutrients (soluble in Mehlich 3 extractant) and clay mineralogy. Several differences were found between rhizosphere soil (RS) and bulk soil. The TOC was 8 times higher and the TN and C pyro were 4 times higher in the rhizosphere than in the bulk soil. Mineralogical results suggest a slightly higher degree of chemical weathering (mainly affecting biotite and amphibole minerals) in the RS than in bulk soil, consistent with significantly higher nutrient bioavailability in RS (Ca, Mg, K, Co, and Fe). On the other hand, the higher concentrations of C and metals extracted with sodium pyrophosphate suggest the formation of more metal–organic complexes in the rhizosphere than in the bulk soil. This metal fraction is considered as readily mobilizable and available and can be leached from the soil to continental and coastal waters. This effect will be enhanced in cold climates by expansion of plant cover due to the increased temperature expected under climate change. [ABSTRACT FROM AUTHOR]

Highlights: [•] We determined total concentration and fractionation of metals in an old Pb/Zn-mining area. [•] We evaluated metal accumulation by native plants growing on mine-soils. [•] Mine-soils showed neutral pH and a high concentration of Cd, Hg, Pb and Zn. [•] Plants were pseudometallophytes with potential application in phytoremediation. [Copyright &y& Elsevier]

Abstract: A semi-arid mangrove estuary system in the northeast Brazilian coast (Ceará state) was selected for this study to (i) evaluate the impact of shrimp farm nutrient-rich wastewater effluents on the soil geochemistry and organic carbon (OC) storage and (ii) estimate the total amount of OC stored in mangrove soils (0–40cm). Wastewater-affected mangrove forests were referred to as WAM and undisturbed areas as Non-WAM. Redox conditions and OC content were statistically correlated (P<0.05) with seasonality and type of land use (WAM vs. Non-WAM). Eh values were from anoxic to oxic conditions in the wet season (from −5 to 68mV in WAM and from <40 to >400mV in Non-WAM soils) and significantly higher (from 66 to 411mV) in the dry season (P<0.01). OC contents (0–40cm soil depth) were significantly higher (P<0.01) in the wet season than the dry season, and higher in Non-WAM soils than in WAM soils (values of 8.1 and 6.7kgm−2 in the wet and dry seasons, respectively, for Non-WAM, and values of 3.8 and 2.9kgm−2 in the wet and dry seasons, respectively, for WAM soils; P<0.01). Iron partitioning was significantly dependent (P<0.05) on type of land use, with a smaller degree of pyritization and lower Fe-pyrite presence in WAM soils compared to Non-WAM soils. Basal respiration of soil sediments was significantly influenced (P<0.01) by type of land use with highest CO2 flux rates measured in the WAM soils (mean values of 0.20mgCO2 h−1–g−1 C vs. 0.04mgCO2 h−1–g−1 C). The OC storage reduction in WAM soils was potentially caused (i) by an increase in microbial activity induced by loading of nutrient-rich effluents and (ii) by an increase of strong electron acceptors [e.g., NO3 −] that promote a decrease in pyrite concentration and hence a reduction in soil OC burial. The current estimated OC stored in mangrove soils (0–40cm) in the state of Ceará is approximately 1milliont. [Copyright &y& Elsevier]

Abstract: The potential of soils as a sink of atmospheric carbon and the implications related to mitigate greenhouse-gas emissions are well recognized. The raising of tree crops on agricultural soils can augment soil-carbon sequestration more than do other agricultural uses such as corn crops. Thus, 6 plots with different durations of use as poplar plantation (5, 10, 20, 30, 50, and 100 years) were studied in comparison with 6 adjacent plots with corn crop. The carbon pool in poplar-plantation soils was positively correlated to the time of use at the three soil depths studied (0–20, 20–50, and 50–100cm), the mean annual increase being 1.16Mg C ha−1 year−1. Poplar-plantation soils also increased the total carbon content in a more effective way because the duration of use was also correlated with the most recalcitrant carbon forms. Therefore, land-use change from corn crops to poplar-plantation soils is economically profitable as well as positive both for the total organic-carbon pool as well as for the efficiency of carbon sequestration by the increase of non-oxidizable forms in the soil. [Copyright &y& Elsevier]

Abstract: The rhizosphere is a narrow zone of soil influenced by plant root and their exudates and its extent varies with soil type, plant species, age and many other factors. The rhizosphere microenvironment therefore has different characteristics from those of bulk soils. In the present study, the physicochemical parameters, exchangeable micronutrients (extracted with 1M NH4Cl), available micronutrients (extracted with Mehlich-III: Fe, Mn, Cu, and Zn), toxic metals (Cr, Pb, Ni, Cd), the Fe associated with the organic matter (extracted with Na-pyrophosphate) and the poorly crystalline Fe (extracted with 0.2M oxalic acid) were studied in the bulk soil and in the rhizosphere of the spontaneous vegetation growing at an abandoned copper mine. The natural vegetation colonising the mine dump included two species of Ericaceae (Erica cinerea, Calluna vulgaris) and Salix atrocinerea, whereas only the first two grew on the mine slope. The results showed that plants influence the physicochemical conditions of the rhizosphere, although not all in the same way. Thus the pH of the rhizosphere of the ericaceous species was extremely low, approximately 2–3units lower than the pH of the bulk soil, whereas the pH of the Salix rhizosphere remained close to the respective bulk soil, which has a pH of 6.6. Furthermore, the concentration of organic matter was higher in the rhizosphere than in the bulk soil. In general the same pattern was observed for the most labile fractions of the micronutrients and toxic metals, with higher concentrations in the rhizosphere than in the bulk soil. However, there were clear differences between the ericaceous species and Salix, which prevents general conclusions being reached about the processes to which trace metals are submitted in the rhizosphere. On the other hand, although the elements under study are included in the term trace metals, they display different geochemical behaviour. Thus the exchangeable fraction was clearly correlated with the TOC for all micronutrients except Cu, presumably because the organic matter selectively adsorbs this element, thereby reducing its mobility. Finally, as regards the potential toxicity, only the concentrations of Cu and Fe surpassed the limits above which phytotoxicity may occur, while toxic metals were present at very low concentrations. [Copyright &y& Elsevier]

Soil organic matter (SOM) in Alu-andic Andosols and Alu-humic Umbrisols is believed to accumulate because of the protection caused by binding to aluminium (Al). We investigated soils that differed in the abundance of organo-Al complexes to determine the effect of such binding on SOM chemistry. For this, the surface horizons of three types of acid soils in the Basque Country (northern Spain) under forest stands were studied: (i) Alu-andic Andosols (AND soils) on basalts and trachytes, (ii) Umbrisols or so-called 'aluminic'(ALU) soils also on basalts and trachytes and (iii) soils with a podzolizing trend (POD), on quartzites. Values of Al extractable with sodium pyrophosphate (Alp) in the surface horizons of these soils ranged between 8.5 and 13.1, 1.9 and 9.3, and 0.8 and 3.7 g kg−1 dry weight, for the AND, ALU and POD soils respectively. For POD and ALU soils, surface horizons were sampled at two depths, 0-5 and 5-20 cm, whereas the AND soils were sampled at different depths down to the B horizon. NaOH-extractable SOM from three AND soils, 12 ALU soils and 12 POD soils was studied by pyrolysis-gas chromatography/mass spectrometry. The POD soils had the largest loads of plant-derived markers (lignin, long-chain alkanes and alkenes, methyl ketones, fatty acids); SOM of the AND soils had the smallest amounts of plant-derived SOM and the largest amounts of microbial products (microbial sugars and N-compounds) of the soils studied. ALU soils had an intermediate pattern, as expected. The results indicate that the SOM of Alu-andic Andosols, developed from basalt and trachyte rocks, is essentially dissimilar to that of soils derived from quartz-rich parent material, under the same climate conditions and similar forest stands. The dominance of secondary (microbial-derived) SOM in Alu-andic Andosols, also observed in previous research on Sil-andic Andosols (these are dominated by short-range ordered Si compounds in contrast to the dominance of organo-Al complexes in Alu-andic Andosols), reveals the small contribution of primary (plant-derived) material to SOM in soils with andic properties. [ABSTRACT FROM AUTHOR]

Abstract: Different analytical techniques were used to find the most reliable and economic method for determining the labile fraction of C in biochar. Biochar was produced from pine, poplar and willow (PI, PO and WI, respectively) at two temperatures (400 and 550°C) and characterised using spectroscopic techniques [solid state 13C nuclear magnetic resonance spectroscopy (NMR)], molecular markers [pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS)], thermogravimetry (TG), elemental composition and wet oxidation (potassium permanganate and potassium dichromate). Short term incubation (110h) of an A horizon from an Umbrisol amended with the biochar samples at two doses (7.5 and 15tha−1) was also carried out to provide supplementary information on the influence of biochar–soil interaction on CO2 evolution. Spectroscopic analysis demonstrated that the degree of biochar carbonisation was influenced by the type of feedstock and heating conditions and followed the order WI-400

Abstract: Concentrations of the isomers of the organochlorine pesticide hexachlorocyclohexane (HCH) were determined in 252 surface soil samples collected within a sampling network covering agricultural areas in Galicia (NW Spain). The concentration of total HCH (sum of α+β+γ+δ) ranged between 4 and 2305ngg−¹ (dry weight), with the α-HCH and γ-HCH isomers predominating (<1–1404ngg−¹ and <1–569ngg−¹, respectively). The distribution of the pesticide residues was very heterogeneous, with the largest concentrations present in one of the studied areas (the province of A Coruña). The distribution of HCH was not found to be related to any soil property (organic matter, pH, clays, and metals). Multivariate statistical analysis of the data revealed that three populations of samples with a defined composition of HCH, can be related to the source of HCH: technical HCH (α/γ>3), lindane (99% γ-HCH), or both. The existence of a third population consisting almost exclusively of α-HCH suggests that background contamination of anthropogenic origin dates from several decades ago. The detailed analysis of these populations enabled the possible temporal scale of the application of these pesticides to be deduced. [Copyright &y& Elsevier]

The present study was carried out to test the viability of a method of reductive dehalogenation of α-, β-, λ, and δ-hexachlorocyclohexane (HCH) in soil slurry systems. The soil slurries were maintained under anaerobic conditions, with titanium(III) citrate as a reducing agent and hydroxocobalamin (vitamin B12a) as a catalyzing agent. Experiments were carried out with two soil samples with markedly different characteristics (particularly regarding organic matter content), at a small scale and larger reactor scale. HCH concentration was monitored throaghout the 24 h duration of the tests. In the low organic matter soil HCH isomers degraded rapidly, in both the small scale and reactor systems, and undetectable levels (<0.5%) were reached within 5 h. However, complete degradation of HCH isomers was not achieved in soil with high organic mailer content and there were differences between the results obtained in the small scale and reactor systems. In the small scale system, the levels of degradation reached 93, 88, 94, and 91%, for α-, β-, λ-, and δ-HCH, respectively, and the nondegraded HCH was sorbed in the soil. In the reactor system, the reaction stopped after two hours (no more than 65% of any of the isomers was degraded). [ABSTRACT FROM AUTHOR]

Abstract: Although there are many studies on the characterization of C in biochar and its C sequestration potential, there is little knowledge on the mineral fraction in biochar and its weathering. The latter, however, can have powerful implications on nutrient availability. In the present study, a modified Soxhlet reactor was used to simulate the long-term geochemical weathering of an ash-rich biochar produced from sewage sludge of a non-industrial area in New Zealand. The weathering process took place during a period of 300h, with and without the addition of humic acid (1.00g added to 20.00g of biochar), and the treatments were referred to as treatment BC-HA and BC-B, respectively. Both the leaching kinetics and the transformations within the solid phase were studied. The results revealed that substantial amounts of K (8.5–10.2%) and S (20.2–28.3%) were recovered in the weathering solutions. Noticeable Ca (17.9–20.7%) and P (15.4%) in the solid were released but only a few were recovered in the weathering solutions because of the precipitation. The presence of humic acids increased this dissolution and thus the availability of K, S, Ca, Mg and P, but induced N immobilization. Nitrogen availability was already very low (<1.0% of the total N) due to the probable recalcitrant heterocyclic N structure. The pH of the biochar samples dropped from 8.4 to 7.5; this was mainly attributed to loss of base cations through leaching and probable carbonation of the system. The XPS spectra evidenced the oxidation of C in biochar during the weathering process with the formation of carbonyl and carboxylic functional groups. The results obtained in this study showed some promise for the positive use of modified Soxhlet extractor in simulating the geochemical weathering in ash-rich biochars and providing a better understanding on the kinetics of nutrient release. This will be key information in assessing the added value of biochars as soil amendments. [ABSTRACT FROM AUTHOR]

Abstract: Mixtures of organic and inorganic wastes were incubated to examine the changes in organic C (OC) contents. An anaerobic sludge and a CaO-treated aerobic sludge, with OC concentrations of 235 and 129gkg−1, were used. The inorganic wastes used – referred to as “conditioners” – were shot blasting scrap, fettling, Linz-Donawitz slag, foundry sand (FS), and fly ash from wood bark combustion (FA). The total OC (TOC) and oxidized OC were determined. DTA-TGA profiles and FTIR spectra were also obtained. Mixtures made with the FS contained significantly lower (P <0.05) amounts of TOC (45gkg−1) than the rest of mixtures, which was attributed to the non-existence of reactive surfaces in the conditioner and the increased aeration induced by this material. Those made with FA contained significantly higher (P <0.05) amounts of TOC (170gkg−1), which was attributed to: (i) the addition of an extra source of C – black carbon (BC) – in the FA, and (ii) the inhibition of mineralization from the compounds present in this conditioner (e.g., amorphous aluminosilicates, BC). The results highlight the importance of the characteristics of the conditioners on the fate of the OM originating from the sludges. [Copyright &y& Elsevier]

Abstract: Five zones along a transect of 180 m were selected for study on the Island of Pai Matos (Sao Paulo, Brazil). Four of the zones are colonised by vascular plants (Spartina SP, Laguncularia LG, Avicennia AV and Rhizophora RH) and were denominated soils, and the other zone, which lacks vegetation, was denominated sediment (SD). The geochemical conditions differed significantly in soils and sediment and also at different depths. The soils were oxic (Eh>350 mV) or suboxic (Eh: 350–100 mV) at the surface and anoxic (Eh<100 mV) at depth, whereas in the sediment anoxic conditions prevailed at all depths, but with a lower concentration of sulphides in the pore water and pyrite in the solid fraction. Under these geochemical conditions Fe is retained in the soils, while the Mn tends to be mobilized and lost. The most abundant form of iron oxyhydroxide was lepidocrocite (mean concentration for all sites and depths, 45±19 µmol g−1), followed by goethite (30±19 µmol g−1) and ferrihydrite (19±11 µmol g−1), with significant differences among the mean concentrations. There was a significant decrease with depth in all the types of Fe oxyhydroxides measured, particularly the poorly crystalline forms. The pyrite fraction was an important component of the free Fe pool (non-silicate Fe) in all soils as well as in the sediment, especially below 20 cm depth (mean concentration for all sites and depths, 60±54 µmol g−1). Furthermore, the mean concentration of Fe-pyrite for all sites and depths was higher than that obtained for any of the three Fe oxyhydroxides measured. The Fe-AVS was a minor fraction, indicating that the high concentrations of dissolved Fe in the soils in the upper area of the transect result from the oxidation of Fe sulphides during low tide. Mössbauer spectroscopy also revealed that most of the Fe(III) was associated with silicates, in this case nontronite. The presence of crystals of pyrite associated with phyllosilicates in samples from the upper layer of the soils may indicate that pyritization of this form of Fe(III) is more rapid than usually reported for ocean bed sediments. The sequential extraction of Mn did not reveal any clearly dominant fraction, with the Mn-carbonate fraction being the most prevalent, followed by exchangeable Mn and oxides of Mn, whereas pyrite-Mn and Mn associated with crystalline Fe-oxides were present at significantly lower concentrations. The high concentration of dissolved Mn found in the soils in the lower part of the transect is consistent with the fact that the solubility is determined by the carbonate fraction. Unlike for Fe, in the soils in the higher zone, which are subject to intense drainage during low tide, there was loss of Mn, as reflected by the concentration of total Mn. [Copyright &y& Elsevier]

The objective of this study was to determine to what extent the attenuation or loss of andic soil properties caused by land use change – from forest (FOR, average C content 118.2 ± 23.7 g kg−1) to agricultural land (AGR, average C content 55.7 ± 16.7 g kg−1) use – is reflected in soil organic matter (SOM) at the molecular level. For this, NaOH-extractable SOM of A horizons from 17 soils developed on amphibolitic parent material in NW Spain was studied by pyrolysis gas chromatography spectrometry (Py-GC/MS). We also included two buried andic A horizons (PAL, 2200 cal yr BP in age) on the same parent material, as a reference for the molecular composition of SOM from soils without recent litter additions. Organic matter of PAL soils had a composition largely different from that of superficial soils (FOR and AGR), with an important relative contribution of microbial polysaccharides and N-compounds, and an absence of compounds that characterize fresh plant litter (e.g. lignins). In the superficial soils, the relative contribution of lignin-derived compounds was greater in AGR than in FOR soils. Differences were also observed in the relative contribution of aliphatic compounds, FOR soils being enriched in this type of components compared with AGR soils. The results indicated that land use change from FOR to AGR, which was accompanied by a decrease in total SOM, resulted in an enrichment in primary SOM. The smaller relative abundance of primary SOM derivatives in andic FOR soils indicates that these compounds were quickly degraded in Andisols. [ABSTRACT FROM AUTHOR]

Abstract: Mixtures of wastes were prepared to improve on the characteristics of the individual ingredients as Technosols, with special attention given to heavy metal extractability. An anaerobic digested sewage sludge and a CaO-treated aerobic sludge were used. A mixture of the two sludges (50:50 DW basis) was also prepared to provide a third type of sludge. The residues were mixed with other types of waste, such as fly ash, Linz-Donowitz slag, foundry sand, shot blasting machine scrap, fettling and barley straw. Extractability of Cu, Cr, Ni, and Zn by 0.01M CaCl2 extraction () was carried out, and leachability of these elements was estimated by acidification of an aqueous suspension of the mixtures with 0.5N acetic acid (Meacetic). The total concentrations of the metals were also determined (MeT). The /MeT ratios for Cu and Ni (means: 4.0% and 3.1%) were higher than those for Cr and Zn (means: 0.07% each). The mean Meacetic/MeT ratios followed the order Ni, Zn, Cu, and Cr (19.5%, 4.1%, 3.7%, and 0.09%, respectively). The results highlight the existence of complex interactions among organic matter solubility, pH and heavy metal extractability. [Copyright &y& Elsevier]

Abstract: Humic substances (HS) from salt marsh soils were characterized and the relationships among HS composition and some geochemical factors were analysed. For this, three salt marshes with the same vegetation cover (Juncus maritimus), but with different geochemical characteristics, were selected. The qualitative characterization of the soil humic acids and fulvic acids was carried out by elemental analysis, FTIR spectroscopy, fluorescence spectroscopy and VACP/MAS 13C NMR spectroscopy. HS from salt marsh soils under sea rush (Juncus maritimus) displayed some shared characteristics such as low degree of humification, low aromatic content and high proportion of labile compounds, mainly polysaccharides and proteins. However, although the three salt marsh soils under study were covered by the same type of vegetation, the HS showed some important differences. HS composition was found to be determined not only by the nature of the original organic material, but also by environmental factors such as soil texture, redox conditions and tidal influence. In general, an increase in the humification process appeared to be related to aerobic conditions and predominance of sand in the mineral fraction of the soil, while the preservation of labile organic compounds may be associated with low redox potential values and fine soil texture. [Copyright &y& Elsevier]

The minerals of the clay fraction in estuarine plains are mainly detrital, being a mixture of marine and continental sediments, but can also be authigenic. Because of the importance of mangrove ecosystems in tropical estuarine areas and the relatively few existing studies of the mineralogical composition of soils in these environments, the aim of this study was to determine the mineralogical assemblage and identify potential contrasts along the coast of the State of São Paulo. Soils from 11 mangroves distributed along the coastal plain of the State of São Paulo were sampled at depths of 0 to 20 and 60 to 80 cm, and samples of suspended sediments from the Ribeira do Iguape River were collected for analysis. Mineralogical analyses were performed on the clay and silt fractions by x-ray diffraction (XRD) and transmission electron microscopy, and fresh soil samples were analyzed by scanning electron microscopy-energy dispersive spectrometry and suspended sediments by XRD. The silt fraction contained quartz, feldspars, gibbsite, kaolinite, illite, and vermiculite, and the clay fraction contained smectite, kaolinite, illite, gibbsite, quartz, and feldspars. Locally, vermiculite, biotite, anatase, halloysite, and goethite may occur because of recent transport of sediments to the system. Pyrite was identified in fresh samples. The allochthonous minerals found either were terrestrial and transported by rivers or had originated from the continental platform by past transgressive events. We suggest that the neoformation of smectite and kaolinite occurs in mangrove soils. Different geomorphological settings along the São Paulo coast appear to regulate mineral distribution in mangrove soils. [ABSTRACT FROM AUTHOR]

Abstract: Solid-phase analysis was undertaken to obtain information on the effects of bioturbation (activity of plants and macrofauna) on the distribution of different forms of iron and sulfur in a mangrove ecosystem in Brazil. A seasonal study involving four compartments from a mangrove forest (UN: an unvegetated mudflat; SP: a low intertidal zone colonized by Spartina alterniflora; RH: monospecific forest of Rhizophora mangle and; AV: monospecific forest of Avicennia schauerianna) was carried out. Pyrite-Fe, oxyhydroxides-Fe, acid volatile sulfide (AVS), degree of pyritization (DOP), pH and Eh were determined. The results show an intense effect of mangrove vegetation on soil redox processes. Higher live root densities (56–132 g m−2) in surface layers (0–10 cm) from vegetated sites led to suboxic/oxic conditions (129–374 mV), pyrite oxidation, and acidic (3.8–5.5) conditions, showing the role of plant activity on iron sulfide biogeochemistry. The combination of more oxidizing conditions and pyrite oxidation process also favored oxyhydroxide precipitation, as indicated by higher values of oxyhydroxides-Fe found in superficial layers. In contrast, vegetated zones presented higher values of pyrite-Fe than UN, indicating that root exudades may stimulate the activity of sulfate-reducing bacteria. The results show a clear seasonal variation in AVS and pyritic fractions. In summer, the elevated temperatures cause higher evapotranspiration rates and plant activity which intensified the oxidation of iron sulfides. Thus, at all sites the AVS and pyrite-Fe values were substantially lower during summer (especially in superficial layers). A clear seasonal pattern was also observed in the unvegetated mudflat compartment. The lowest pyrite-Fe, DOP and AVS values, observed in summer, appear to be related to increased crab activity (Uca spp), probably because of more intense foraging and reproductive activity. [Copyright &y& Elsevier]

Abstract: Morphological and analytical data corresponding to several profiles from two mangrove systems in the Brazilian state of São Paulo were examined for evidence of pedogenetic processes. Plant activity exerted a strong effect on the processes occurring in mangrove substrates, especially on the intensity of these processes and, therefore, constitutes one of the major factors involved in the differentiation of sediments and soils. Colonization of substrates by vascular plants leads to drastic changes in physicochemical conditions. The redox processes were much more diverse in the soil than in the sediment (substrate without vegetation); in the former they varied with depth, with oxic or suboxic conditions being observed at the surface and anoxic conditions observed below 30 cm, whereas in the sediment, anoxic conditions were observed throughout. Likewise, the acid–base conditions were more variable in the soils, ranging from strongly acid to neutral, and in the sediment they were close to neutral. Furthermore, different pedogenetic processes were identified: (1) addition of organic matter by accumulation of vegetable debris and dead roots, with formation – in some cases – of a histic epipedon, (2) transfer of soluble iron (Fe2+) towards the surface and precipitation in the form of Fe oxyhydroxide, and transfer of the mineral particles due to the bioturbation caused by activity of crabs, (3) transformation of elements such as iron (gleization) and sulphur (sulphidization). Changes undergone in the mangrove substrates were also characterized by simultaneity and intergradations between pedogenesis and diagenesis, especially in the lowermost layers in which authigenesis appears to intensify. Thus, the presence of smectite minerals in the clay fraction may be attributed to authigenic processes that take place in both soils and sediments. [Copyright &y& Elsevier]

Pore-water and solid-phase analysis was undertaken to study the effects of different environmental conditions on redox processes in mangrove soils on the southern coast of Brazil. Three Rhizophora mangle (L.) mangrove forests were studied in different physiographic positions-riverine, fringe, and basin forest-and substrate compositions. Our results indicate different geochemical conditions in soils from different physiographic positions. In the fringe soils, the low acid-volatile sulfide and pyrite Fe contents, associated with high values of Fe2+ in pore water, indicate oxic and suboxic conditions in surface layers (0-10 cm). Below this depth, anoxic conditions prevail and sulfate reduction becomes the dominant process of organic matter decay, as indicated by higher concentrations of dissolved HS and pyrite Fe. In the basin forest, long periods of tidal flooding and low rates of litter export maintained anoxic conditions and high organic matter contents, necessary for anoxic respiration to take place, as shown by the low Fe2+ and HS- concentrations in pore water, along with high degree of Fe pyritization values and high concentrations of pyrite Fe. In the riverine soils, the lowest concentrations of pyrite Fe and the highest concentrations of HSin pore water were obtained in response to low availability of reactive Fe (0-10cm, 31.8 ± 8.0 mmol kg-1; 20-30 cm, 43.2 ± 32.3 mmol kg-1) due to its sandy texture, which limits pyrite synthesis. Our results indicate that the participation and intensity of each process may vary within different physiographic positions because of the effects on the frequency and duration of tidal flooding and soil composition. Our results also show that R. mangle is present on substrates with different geochemical conditions (oxic, suboxic, and anoxic). [ABSTRACT FROM AUTHOR]

Abstract: In order to be able to make predictions about the bioavailability and transport of contaminants and nutrients in soils, detailed knowledge is required about the adsorption of natural organic matter on the surface of oxides, as well as the processes of competition with the different ions present in the soil. With this aim, experiments investigating the adsorption of a soil humic acid (SHA) on goethite were carried out at pH 4.5, 7.0 and 10.0 and ionic strengths of 0.1 and 0.01 M, and the competition between SHA and phosphate was analysed by performing adsorption isotherms and electrophoresis experiments. Adsorption of SHA was clearly dependent on pH and ionic strength, decreasing with increasing pH or decreasing ionic strength. The results show that SHA and phosphate compete for the goethite surface, since the presence of phosphate decreases the adsorption of SHA and the presence of SHA decreases the adsorption of phosphate. Under certain conditions of pH, a decrease in phosphate adsorption of up to 45% and a decrease of SHA adsorption between 20 and 35% is produced. Furthermore, experiments performed by varying the order of addition of adsorbates to the goethite dispersion suggest that equilibration is attained more quickly when the adsorbates are added simultaneously than when one of the adsorbates is added before the other. [Copyright &y& Elsevier]

Abstract: Spatial variation in salinity, pH, redox potential, and in the concentrations of dissolved Mn, Fe2+ and sulphides in pore water were investigated in a mangrove system in the state of São Paulo (Brazil). Total organic C (TOC), S, Fe and Mn were analyzed in the solid phase, along with acid volatile sulphide (AVS), density of roots and percentage of sand. Five zones, situated along the length of a 180m transect were considered in the study. Four of these were colonized by different species of vascular plants (Spartina, Laguncularia, Avicennia and Rhizophora) and were denominated soils; the other was not colonized by vegetation, and was denominated sediment. The results indicated important differences between the physicochemical conditions of the pore water in the vegetated zones and the sediment. In the former, two geochemical environments were identified, based on soil depths. The upper 20cm contained the largest quantity of roots, and the conditions were oxic (Eh>350mV) or suboxic (Eh: 100–350mV), acidic, and with high concentrations of Fe and Mn in the pore water. Below this depth, the soil became anoxic, the concentration of sulphides (HS−) increased significantly and the concentrations of dissolved Fe and Mn decreased significantly. The total S and the AVS fraction increased with depth, while TOC concentrations decreased, indicating that the decreases in Fe and Mn were due to the precipitation of metal sulphides. However, clear differences among the vegetated zones were not observed. The sediment was always anoxic, but with low concentrations of sulphide in the interstitial water, and was neutral or slightly alkaline. As in the soils, the concentrations of sulphides and total S increased significantly with depth, indicating that the conditions favoured the synthesis and stability of metal sulphides. [Copyright &y& Elsevier]

En este trabajo se realiza la extracción de compuestos bioactivos de las hojas de Helianthus Annuus L (girasol) utilizando dióxido de carbono en condiciones supercríticas. Se estudia la influencia del almacenamiento de las hojas, una vez recolectadas del campo, en distintas condiciones de presión (100 y 500 bar) y temperatura (35 y 50 °C). Además se dan los promeros pasos para lograr la separación de los componetes mayoritarion en el extracto más bioactivo. Los resultados muestran que es aconsejable trabajar en las condiciones más drásticas utilizadas (50 °C y 500 bar) para obtener los mejores rendimientos. En todas las condiciones de extracción utilizadas las muestras secas ofrecieron mejores porcentajes de extracción que las húmedas, sin embargo los mejores perfiles de bioactividad se encontraron en estas últimas cuando se extrajeron a 50°C y 500 bar de presión. Las diferentes fases móviles ensayaron arrojaron que la mezcla de solvente hexano: acetono (80:20) es la que brinda mejores resultados separativos, por lo que se seleccionan estos solventes para llevar a cabo la cromatografia en columna. [ABSTRACT FROM AUTHOR]

The effect of the reducing potential on the reductive dehalogenation of the different HCH (hexachlorocyclohexane) isomers has not yet been studied. In the present study, the potential for dehalogenation of α-, β-, σ-, and γ-HCH isomers by the dithiothreitol (DTT) and titanium(lll) citrate (reducing potential at pH 7, -0.33 and -0.48 V. respectively), with and without the addition of hydroxocobalamin was investigated. In the presence of OTT without catalyst, there was no disappearance of any of the HCH isomers studied after 1 h of treatment. However, disappearance of the γ- and α-HCH isomers was observed during the same time period when titanium(lll) citrate was used as the reductant in the absence of catalyst (62.9 and 16.6% disappearance, respectively). Addition of the hydroxo- cobalamin to the DTT system favored mainly the disappearance of γ- and α-HCH (92.9 and 30.8% disappearance after 1 h, respectively); disappearance of δ-HCH and β-HCH was small (11.9%) or negligible, respectively. Addition of the hydroxocobalamin to the titanium(lll) citrate system favored the degradation of all HCH isomers under study: γ- and α-HCH completely disappeared to undetectable levels (<0.1%) after 1 and 2 min, respectively; degradation of 6-HCH and β-HCH was slower than that of the other two isomers, although they had almost completely disappeared (99.9 and 99.6% disappearance, respectively) after 10 and 60 mm, respectively. The order of disappearance, γ-HCH > α-HCH > δ-HCH > β-HCH, coincided with a decreasing order of the axially positioned Cl atoms of these isomers (considering their thermodynamically most stable con- figuration). This study is the first description of the rapid degradation of δ- and β-HCH under abiotic conditions, and the results demonstrate the effect of the reducing potential on the reductive dehalogenation of HCH isomers. [ABSTRACT FROM AUTHOR]

• SOC stock in peninsular Spain was estimated at 3.3 ± 0.4 Pg (0–30 cm) and 4.2 ± 0.9 Pg (0–50 cm). • Using RF modelization, mean annual precipitation (MAP) was the most important predictor variable. • Lithology, soil type, land use and pH are important variables for a given precipitation regime. • Presence or absence of active lime or active Al are key factors of variablility at regional level. • Lowest C stocks (10–30 t ha−1) are in cropland of arid regions (MAP < 400 mm). • Highest C stocks (170–240 t C ha−1) are in acid forest soils of humid regions (MAP 1000–1700 mm) Soil organic carbon (SOC) stocks and their geographical distribution in peninsular Spain were estimated from a georeferenced database consisting of 12,724 surface samples (0–30 cm) and 3607 subsurface samples (30–50 cm), covering different climate, land use, elevation, parent material, soil type and soil pH. SOC density showed a high heterogeneity, with the lowest values in arid regions, where the average in topsoil ranged between 20 and 60 t C ha−1, under woody crops and forest respectively. Carbon stocks gradually increases as precipitation increases, and its variability is also dependent of other factors, fundamentally the presence/absence of active lime or active Al. In semi-arid zones, calcaric soils (pH ≈ 8.3) have higher contents of SOC than neutral to weakly acidic soils from siliceous materials. However, in humid regions, calcareous materials have undergo total or partial decarbonatation in the upper layer (pH < 4.0–7.5) and SOC stocks are markedly lower than in other materials. In forest soils it seems that a steady state (around 100–120 t C ha−1) (0–30 cm) has been reached in a wide range of precipitation, between 900 and 1700 mm; most of this carbon (about 80%) is labile-C. Soils from granitic rocks are acidic (pH 4.5–5.5) (Al buffering) and the mean SOC stock in the indicated precipitation range is between 170 and 200 t ha−1 (it is estimated that approximately 60% is stabilized as metal-C or mineral-C complexes). The highest values (190–240 t ha−1) are recorded in acidic soils derived from mafic rocks, which in these regions usually develop andic properties (around 73% is involved in stable metal-C or mineral C complexes). Finally, the SOC stored in neutral soils from serpentinized ultramafic rocks (without excess Ca or Al) is similar to that of the decarbonated soils derived from calcareous materials. In all regions, forest soils are a much more important SOC sink than live forest biomass (2–4 times higher in the upper 30 cm and 3–6 times greater in the upper 50 cm). Random Forest regression was used as modeling tool and digital mapping. Mean annual precipitation was estimated to be the most important predictor variable, followed by land use, lithology/soil type and soil pH. Model performance was calibrated by the internal RF validation and through cross-validation, and the results were similar. In topsoil, the mean error, root mean square error and R2 were −0.007% C, 1.48% C and 0.61, respectively. In the subsurface layer these indices were −0.020, 1.07 and 0.37, respectively. SOC stock for peninsular Spain was estimated at 3.33 Pg in the upper (0–30 cm) layer, and 0.85 Pg in the subsurface (30–50 cm) layer. Total SOC stock for 0–50 cm was 4.19 Pg, with a 95% confidence interval ranging between 3.33 and 5.03 Pg. [ABSTRACT FROM AUTHOR]