Inorganic Fraction Research Articles

Carbon and nutrients transfer from primary producers to lake sediments – A stoichiometric approach

We aimed to demonstrate different input of organic and inorganic carbon, nitrogen and phosphorus from three main groups of primary producers (phytoplankton, charophytes and vascular submerged macrophytes) to respective lake sediments. Studies were carried out in one eutrophic and two mesotrophic lakes. Samples of sediments were taken from profundal and from littoral zones, the latter divided into such overgrown by charophytes and others covered by vascular submerged macrophytes. We applied a stoichiometric approach to illustrate variable functional carbon to nutrients relationships. Among profundal sediments, the lowest organic to inorganic carbon ratio was found in sediments from the eutrophic lake due to precipitation of calcium carbonate during algal blooms. Extremely low inorganic carbon input to profundal sediment of one of the mesotrophic lakes may be explained by low phytoplankton production but also by dissolution of once deposited calcium carbonates. Charophyte-dominated littoral sediments contained significantly more inorganic carbon than other littoral and profundal sediments. Comparison of stoichiometric ratios between plant standing crop and underlying littoral sediments showed significant enrichment of sediments in nitrogen manifested by reduction of organic carbon to total nitrogen ratio during plant decomposition taking place both in charophyte and in vascular plant stands. We also attempted to divide phosphorus pool in sediments into organic P and calcium-bound P present in charophyte stands and in profundal sediments of eutrophic lake. In the former, calcium-bound P was estimated at 17–19 % of the total P pool while in profundal sediments it amounted 42 % of the total P. This difference suggests that calcium carbonate settling during algal blooms in a eutrophic lake may be more effective in P trapping than calcite encrustations covering charophyte plants in littoral sites. In conclusions, we underline the need of considering often neglected inorganic fractions of carbon and phosphorus to get better insight into carbon and nutrient burial in lake sediments.

Fluorapatite ceramics for bone tissue regeneration: Synthesis, characterization and assessment of biomedical potential.

Calcium phosphates, due to their similarity to the inorganic fraction of mineralized tissues, are of great importance in treatment of bone defects. In order to improve the biological activity of hydroxyapatite (HAP), its fluoride-substituted modification (FAP) was synthesized using the sol-gel method and calcined at three different temperatures in the range of 800-1200°C. Physicochemical and biological properties were evaluated to indicate which material would support bone regeneration the best. X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), and Fourier transform infrared spectroscopy (FTIR) revealed that fluoride ions were incorporated into the apatite lattice structure. In studies it was found that fluorapatite sintered at the highest temperature had the lowest porosity, no internal pores and the highest density. In vitro ion reactivity assessments showed that during the 28-day immersion of the samples in the simulated body fluid, the uptake of calcium and phosphorus ions was inversely correlated to the calcination temperature. All tested materials were non-toxic since the cytotoxicity MTT assay demonstrated that the viability of preosteoblast cells incubated with sample extracts was high. Fluorapatite sintered at 800°C was determined to be of optimal porosity and fluoride release capacity and then used in cell proliferation studies. The results showed that it significantly shortened the doubling time and thus enhanced the proliferation of osteogenic cells, as compared to the fluoride solutions and control group. Therefore, this material is proposed for the use in orthopedic applications and bone tissue engineering.

Organic and inorganic nitrogen deposition on the red pine forests at the northern foot of Mt. Fuji, Japan

Abstract In order to clarify the deposition amounts and processes of bioavailable nitrogen species including organic forms on forests, a simultaneous observation of rainfall, throughfall, stemflow, aerosols, and their precursor gases was conducted for a two-year period at a forested site on the northern foot of Mt. Fuji in Japan. About 80–90% of the rainfall waters reached the forest floor via the throughfall process and the remaining fraction can be considered to be intercepted by the forest canopy and not transported to the forest floor. Partitioning of the rainfall waters into stemflow waters was negligible. Deposition amounts of the total dissolved nitrogen by rainfall, throughfall, and stemflow were 2.204, 2.685, and 0.027 mgN m−2 day−1, respectively, on average. Contributions of the water-soluble organic nitrogen (WSON) to the dissolved nitrogen in the rainfall, throughfall, and stemflow deposition were about 51%, 58%, and 75%, respectively. The major fraction of the nitrogen species in the deposition was the organic forms. Among the inorganic nitrogen, the contribution of NH4+-N to the nitrogen deposition was significantly greater than that of NO3−-N in the rainfall deposition, whereas both were comparable in the throughfall deposition. The deposition amounts of NO3−-N and WSON by throughfall were greater than those by rainfall due to the influence of the dry deposition on the canopies and the leaching from trees, whereas the deposition amount of NH4+-N by throughfall was smaller than that by rainfall due to the uptake by trees. About 58% of the net nitrogen deposition on the forest floor, which is defined as the sum of the deposition amounts by the throughfall and stemflow, was explained by the WSON. In the remaining inorganic fraction, the contributions of NO3−-N and NH4+-N to the net nitrogen deposition were comparable, about 20% and 22%, respectively. The nitrogen deposition amount to the forest floor was estimated to be 2.711 mg m−2 day−1, which is equal to the value of the threshold for the condition of “nitrogen saturation” for the forest ecosystems. The modified canopy budget model can estimate that the contributions of the dry deposition to the sum of the dry and wet deposition were about 90%, 64%, 61%, and 22% for NO2−-N, NO3−-N, NH4+-N, and WSON, respectively. The canopy leaching was found only for the WSON, about 72%, 20%, and 8.5% of the net deposition of the WSON can be explained by the wet deposition, dry deposition, and canopy leaching, respectively. The remaining nitrogen compounds showed the canopy uptake. About 10%, 56% and 32% of NO2−-N, NO3−-N, and NH4+-N deposited on the canopy by the wet and dry processes would be transported to the forest floor and the remaining fractions (about 90%, 44%, and 68%, respectively) would be taken into the canopy. Comparisons of the dry deposition amount with the concentration in the surface atmosphere of the nitrogen compounds suggest that the modified canopy budget model can be considered to be better to estimate the amounts of the dry deposition and canopy exchange.

Mechanical Behavior of Toughened Epoxy Structural Adhesives for Impact Applications

The focus of our study is to identify physical properties of different impact-resistant/toughened structural adhesives and identify/develop an elastic-viscoelastic-plastic model as a function of loading rate by using Ludwik-type equations to be able to predict adhesive behavior at higher loading rates and to make cars more crashworthy. For this purpose, we first characterized eight different commercial toughened epoxy structural adhesives to provide detailed information about their constituents using X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and energy dispersive x-ray spectrometer (EDS). Most (but not all) of the model adhesives contained organic tougheners in the form of carboxyl terminated butadiene acrylonitrile (CTBN) copolymer, as well as polyurethane adducts. The main crystalline inorganic phases were found as calcite (CaCO3), wollastonite (CaSiO3) or calcium silicate (CaSiO3), talc (Mg3Si4O10 (OH)2), zeolite which is an alumina silicate based mineral and has many different elements in its composition (M2/nO·Al2O3·xSiO2·yH2O, M can be Mg, Na, Ca, K, Li). The total amount of inorganic fillers was found to be different in each adhesive. Material behavior of the model adhesives were determined via tensile tests and Single Lap Joint (SLJ) tests in shear. Split Hopkinson pressure bar (SHPB) was also used to measure the strain and stress values at higher strain rates in the order of 102 s−1, which is generally encountered in impact related loading situations. Toughness values in the range ~0.5 to ~1.35 MJ/m3 were observed with the model adhesives tested in tensile mode within the ~3 × 10−3 to 0.18 m/m/s strain rate range. The softening behavior of the elastic moduli at higher strain rates observed during tensile testing was also observed with SHPB testing. It is remarkable that, overall, the modulus magnitudes seem to be similar between the tensile test and SHPB specimens within this softening range of the initial bilinear elastic behavior observed. When the results from bulk (tensile) and bonded (shear) specimens were compared, it was clearly seen that the toughness responses of the adhesives to (tensile/shear) strain rates in the bulk and bonded forms, respectively, were different, with the bonded shear toughness values in the ~25 to ~120 MJ/m3 range within ~1.25 to ~25 mm/mm/s shear strain range. The model adhesive which included just inorganic fillers had the lowest tensile toughness at the lowest tensile strain rate, but the highest slope in its tensile toughness regression line, exhibited the second highest bonded shear toughness. When tested at the extension rates of 25 mm/min and 100 mm/min in bonded lap shear, the same adhesive exhibited limited interfacial failure areas, however the dominant failure mode was cohesive failure. When the extension rate increased further, transition to interfacial (adhesive) failure was observed revealing that interfacial failures do not necessarily diminish adhesive bond toughness. Our observations point to the fact that cohesive deformation/failure processes indicating interfacial separations, inter-particle interactions as well as polymer matrix deformation in high deformation loading scenario as in bonded shear loadings may provide the highest toughness. Apparently, a large inorganic filler weight fraction is not necessary to obtain high shear toughness in bonded form since the highest bonded shear toughness was obtained with the adhesive which had the least amount of inorganic fillers among the model adhesives with 14.72 wt %.

A Successful Case in Waste Management in Developing Countries

Although most of the developing countries have serious problems with the issue of waste management, there have been some success stories including the development of environmental public policies, which had led to better life quality. In most developing countries, waste management considers only two stages: collection and final disposal. The collection system does not include a differentiated collection of the municipal solid waste (MSW), this implies that the valorization of the different waste fractions becomes more difficult to separate and most of them are dumped on uncontrolled sites. Meanwhile, the landfilled sites are limited and usually are about to exceed their capacity. In certain rural and semi-urban localities is common the practice of burning their waste, polluting the air, soil and even water. Local authorities are making some efforts to prevent this type of pollution, but it does not always work properly. However, there are certain successful cases like Teocelo, Veracruz in Mexico. This is a semi-urban locality where the inhabitants have been contributing to waste management in different ways since the year 2000. All the people separate their waste in organic and inorganic. Only the inorganic fraction is managed to the collection system, while a part of the organic fraction is usually composted in homes and the rest is treated in a composting plant. Until now, people of the locality keep this way of living and consider that the care of the environment is important for this generation as well as the new ones.

Valorization of the plastic residue from a WEEE treatment plant by pyrolysis

The possibility of a pyrolysis process as a mean of recycling the residual plastic rich fraction (WEEE residue) derived from of a material recovery facility has been evaluated. The unknown product composition of WEEE residue has been supposed through coupled thermal – infrared analysis and ultimate analysis and resulted as PP 3 wt%, PBT 3 wt%, PVC 4 wt%, styrene-based polymers (principally ABS) 50 wt%, thermosetting resins (principally, epoxy/phenolic resins) 24 wt%, inorganic fraction (principally fiber glass) 16 wt%. DSC experiments showed that the overall energy, defined as the degradation heat, needed in order to completely degrade WEEE residue was about 4% of the exploitable energy of the input material. The effect of temperature and different zeolite catalysts were investigated, in particular in terms of yield and quality of the produced oils during the pyrolysis process. Produced oils were potentially exploitable as fuels and almost all catalysts improved their quality. The best performance was reached by NaUSY(5.7) with the second highest production of light oil and the greatest total monoaromatics yield, plus 12 wt% in comparison to thermal pyrolysis experiments. Furthermore, light oil produced by NaUSY(5.7) has one of the best LHV (36 MJ/kg) and no halogenated compounds were detected by GC–MS analysis. Char or pyrolytic gas combustion could supply the energy required for the thermal degradation of WEEE Residue.

Phosphorus lability increases with the rehabilitation advance of iron mine land in the eastern Amazon

Impacted areas by iron mining may face challenges in the management of phosphate fertilization and reduced efficiency of rehabilitation practices, thus extending the time required for the rehabilitation of these areas. The objective of this study was to evaluate phosphorus (P) lability in soils of native forest and ferriferous canga areas (savanna vegetation above ironstone outcrops covering iron ore deposits) and in iron mine waste piles undergoing rehabilitation. Benches of the analysed waste pile differ in age of rehabilitation: as the initial rehabilitation stage (INI), we consider benches with fewer than 3years of rehabilitation; the intermediate stage (INT) were benches with up to 5years of rehabilitation; and the advanced rehabilitation stage (ADV) corresponds to benches with more than 8years of rehabilitation activities. Organic and inorganic P fractions were analysed in these areas by chemical fractionation and were classified according to the degree of soil lability. The results show that in the canga environment, there was a predominance of inorganic fractions of moderate lability and moderate stability, with a strong dependency of the soil organic matter (SOM) on the P fractions, whereas there was a greater participation of the moderately labile organic fractions in the forest than in the canga. On the other hand, in the rehabilitation areas, there was an increase in the labile organic and inorganic fractions as the rehabilitation process advanced. The distribution of P in areas undergoing rehabilitation indicates that there is a tendency for P levels to resemble those of native environments, such as the forests.

Physical Indicators of Cambisols Under Agricultural Uses in Chapada do Apodi, Semiarid Region of Brazil

Soil physical structure is related to porous space dynamics, which is affected by pedogenetic conditions, land uses, and agricultural practices. Thus, the objective of this work was to evaluate physical and structural attributes of Cambissolos under different uses in the Terra de Esperança Settlement Project, in Chapada do Apodi, Governor Dix-Sept Rosado, Rio Grande do Norte, Brazil, and detect the most sensitive attributes for the distinction of environments using multivariate analysis. The study areas with different land uses were: Native Forest Area 1 (NFA1), Native Forest Area 2 (NFA2), Native Forest Area 3 (NFA3) (reference areas), Conventional Management Area (CMA) Agroecological Area (AEA), and Cajaraneira (Spondia sp.) Orchard Area (COA). Areas with agricultural uses were characterized through physical and structural analyses, using disturbed and undisturbed soil samples collected from their 0.00-0.10, 0.10-0.20, and 0.20-0.30 m soil layers. The soil classes of the areas, according to the Brazilian Soil Classification System (SiBCS) were Cambissolo Haplico Carbonatico vertissolico (NFA1); Cambissolo Haplico Ta Eutrofico tipico (NFA2 and COA); Cambissolo Haplico Ta Eutrofico vertissolico (NFA3); and Cambissolo Haplico Carbonático tipico (CMA and AEA). The results of the attributes analyzed were expressed as mean of three replications per soil layer of each area, using multivariate analysis. Soil textures varied from sandy clay loam to clay. The total sand fraction presented negative correlations with clay dispersed in water, gravimetric moisture (GM), volumetric moisture (VM), total porosity determined (TPd) and microporosity (MiP); and positive correlations with soil density (SD), and basic infiltration rate (BIR), denoting pedogenetic influence. The SD presented significant correlation with GM, VM, TPd, MiP, macroporosity (MaP), aeration porosity (AP) and BIR, denoting its importance for the physical structure of the soil, and its dynamics. The most relevant attributes for the discrimination of the soil physical structure were the inorganic fractions clay and sand, porosity, degree of flocculation, aggregates, and soil mechanical resistance to penetration. The physical and structural attributes of the Cambissolos Haplicos were generally preserved, when compared to the current conditions of the NFAs, despite the different land use and managements. However, the soils of NFA1 (0.20-0.30 m layer), CMA, and AEA areas indicate fragility in aggregate stability and degree of flocculation due to the predominance of the sand fraction. The COA presented more favorable physical and structural conditions to the development of agricultural crops, especially on the surface layers, mostly influenced by their clay, TPd, AP, GM, VM, and soil mechanical resistance to penetration.

Graphitic carbon nitride-doped sewage sludge as a novel material for photodegradation of Eriochrome Black T.

The bio-resource utilization of sewage sludge is presented by preparation of novel waste sludge-doped graphite carbon nitride (g-C3N4) photocatalyst. The sludge flocs which constitute bacteria and organic substances served as a pore-forming framework in the catalyst, while the inorganic fractions including those transition metals and crustal metals can function as dopants for sludge-based g-C3N4 composite. The physicochemical properties of as-prepared catalyst were well analyzed by multiple characterizations. The composite catalyst showed higher surface area (50m2/g) and more mesoporous structures (8.9 × 10-2cm3/g) as compared with pristine g-C3N4 (8.4m2/g and 6.6 × 10-2cm3/g, respectively). The photoelectrochemical results showed that introduced sewage sludge impurities lowered down the photocarriers recombination efficiency and enhanced more efficient electron-hole separation by about 100 times. The photocatalytic activity was tested by degradation of typical dye Eriochrome Black T (EBT). The optimal sample improved removal of EBT by 56% in 90min under ultraviolet irradiation (λ = 254nm). According to the results of main metal ion leaching concentration and reuse tests, the composite catalyst exhibited excellent stability and repeatability.

Soil organic matter relationships with the geotechnical-hydrological parameters, mineralogy and vegetation cover of hillslope deposits in Tuscany (Italy)

Soil organic matter (SOM) represents a main fraction of superficial soil characterized by a mechanical-hydrological behaviour different from that of the inorganic fractions. In this study, a method to measure the SOM content was applied to 27 selected sites in Tuscany (central Italy) characterized by the presence of soil types common in the region: cambisols and regosols. The method included the contribution from root fragments, which is a fraction often neglected or underestimated in measurements, in the overall estimate of the SOM content. The retrieved SOM contents were analysed considering the vegetation cover at the sites and the selected attributes of geological interest, such as geotechnical parameters and the mineralogical composition of the soils. The SOM normalized to the bulk samples ranges between 1.8 and 8.9% by weight, with the highest values of the SOM content being associated with vegetation cover classes of forest and woodlands without shrubs. The SOM values showed close relationships with the abundance of the finer fractions (silt and clay) of the soil samples, and considering the relations with geotechnical properties, moderate correlations were found with the plasticity index, unit weight and effective friction angle, overall demonstrating the importance of considering SOM when the geotechnical and hydrological properties of soils are evaluated.

Evaluation of the influence of cultivation on the total magnesium concentration and infusion extractability in commercial arabica coffee

Coffee is considered an important source of organic nutrients and minerals, and these resources are strongly affected by agricultural management. Among the minerals, the element Mg is important, which is essential for both plants and humans. In this work, the effects of agricultural management on the absorption and storage of Mg by commercial, ground, roasted Arabica coffee were investigated. For this purpose, some Mg and P fractions were evaluated. It was observed that Mg stored in the grain was concentrated in the inorganic fraction, with an average extraction of 102% and in conventional samples and 119% in organic samples. These results suggest that in these samples Mg is probably largely presented as different inorganic salts. Phytate and organic acid salts are two possibilities discussed in this work that could explain this hypothesis. This can be corroborated by the extraction of Mg in the infusion of hot water.

Effects of phosphorus fertilizer application on phosphorus fractions in different organs of Cordia trichotoma

The application of phosphorus (P) to soil can increase its availability to plants and alter P fractions in annual and perennial organs of Cordia trichotoma. If a portion of P accumulates in perennial organs in organic fractions it can be used in the next growth season, possibly decreasing plant dependence on P derived from soil fertilization. However, if P is preferentially accumulated in inorganic fractions in annual organs, plants will be more dependent on phosphate fertilization. This study aimed to evaluate the distribution of P fractions in organs of C. trichotoma grown on sandy soil treated with 120 and 360 kg P2O5 ha−1. The control was a zero application. After 24 months following fertilization, C. trichotoma seedlings were cut and separated into leaves, branches, stems and roots, dried, ground and subjected to chemical fractionation of P, which estimates fractions of total soluble P, soluble inorganic and organic P, lipid P, P associated ribonucleic acid and deoxyribonucleic acid, and residual P. P in annual organs, as leaves, accumulated preferentially in the soluble inorganic fraction in both treatments. In perennial organs such as stems and branches, P accumulated preferentially in the soluble organic fraction. The application of 300% of the recommended dosage (360 kg P2O5 ha−1) promoted the accumulation of P in soluble organic fractions which may contribute to annual growth the following season and be a strategy to reduce the dependence of 2-year-old stands on soil-derived P and on fertilizers.

Inorganic fraction of oil sands process-affected water induces mammalian macrophage stress gene expression and acutely modulates immune cell functional markers at both the gene and protein levels

The focus of the present study was to examine the acute immunotoxic properties of oil sands process-affected waters (OSPW) using the RAW 264.7 macrophage cell line. Specifically, we used a quantitative PCR assay to monitor changes in the expression of stress, cytokine, and antimicrobial enzyme genes in activated macrophages following acute (i.e. < 24 h) exposure of the cells to whole OSPW and its fractions. Overall, our data shows that OSPW inorganic fraction (IF) significantly induces the expression of genes associated with oxidative stress and DNA damage and that the OSPW-IF also significantly augmented cytokine gene expression. These effects are similar to what was observed following whole OSPW exposures, which contrasts the minimal effects observed when cells were treated with equivalent doses of the OSPW organic fraction (OF). Surprisingly, OSPW-IF had reciprocal effects on gene and protein expression levels of two key macrophage enzymes (e.g. inducible nitric oxide (iNOS) synthase and arginase), which indicates that components within OSPW-IF have the unique ability to alter the overall functional states of macrophage by polarizing them towards an alternatively activated status; concomitant with the reciprocal depression of iNOS levels and enhanced expression and activity of arginase. Collectively, these findings show that at sub-lethal exposure doses, the inorganic constituents of OSPW have significant immunotoxicological properties that could potentially affect innate cellular defense responses of exposed animals.

Toxicological appraisal of the chemical fractions of ambient fine (PM2.5-0.3) and quasi-ultrafine (PM0.3) particles in human bronchial epithelial BEAS-2B cells

New toxicological research is still urgently needed to improve the current knowledge about the induction of some underlying mechanisms of toxicity by the different chemical fractions of ambient particulate matter (PM). This in vitro study sought also to better evaluate and compare the respective toxicities of fine particles (PM2.5-0.3) and their inorganic and organic chemical fractions, and the respective toxicities of the organic chemical fractions of PM2.5-0.3 and quasi-ultrafine particles (PM0.3). Human bronchial epithelial BEAS-2B cells were also exposed for 6–48 h to relatively low doses of PM2.5-0.3 and their organic extractable (OEM2.5-0.3) and non-extractable (NEM2.5-0.3) fractions, and the organic extractable fraction (OEM0.3) of PM0.3. We reported that not only PM2.5-0.3, but also, to a lesser extent, its inorganic chemical fraction, NEM2.5-0.3, and organic chemical fraction, OEM2.5-0.3, were able to significantly induce ROS overproduction and oxidative damage notwithstanding the early activation of NRF2 signaling pathway. Moreover, for any exposure, inflammatory and apoptotic events were noticed. Similar results were observed in BEAS-2B cells exposed to OEM0.3, rich of polycyclic aromatic hydrocarbons and their nitrated and oxygenated derivatives. In BEAS-2B cells exposed for 24 and 48 h to OEM2.5-0.3 and OEM0.3, to a higher extent, there was an alteration of the levels of some critical proteins even though crucial for the autophagy rather than a real reduction of autophagy. It is noteworthy that the toxicological effects were equal or mostly higher in BEAS-2B cells exposed for 6 and/or 24 h to PM2.5-0.3 from those exposed to NEM2.5-0.3 or OEM2.5-0.3, and in BEAS-2B cells exposed for 6 and/or mostly 24 h to OEM0.3 from those exposed to OEM2.5-0.3. Taken together, these results revealed the higher potentials for toxicity, closely linked to their respective physical and chemical characteristics, of PM2.5-0.3 vs NEM2.5-0.3 and/or OEM2.5-0.3, and OEM0.3 vs OEM2.5-0.3.

Phosphorus Fraction in a Yellow Latosol Cropped Under No-tilage System in the Brazilian Amazon

Phosphorus (P) deficiency is one of the main factors that limits productivity in Brazilian soils. However, soil management under no-tillage system (NT) may alter the availability of P in the soil. The objective of this study was to evaluate the dynamics of P fractions in a dystrophic Yellow Latosol, cropped under no-tillage for a long period of time in the Amazon Biome. The study was conducted on a farm located in the municipality of Paragominas, southeastern Pará. This experiment evaluated plots cultivated in plots at nine (NT9), 11 (NT11) and 13 (NT13) years of no-tillage system adoption, in one plot under conventional cultivation system (CS) and a surrounding area under native forest (NF) at depths of 0-10, 10-20, 20-30 and 30-40 cm. The soil samples were subjected to P chemical fractionation to determine the different fractions. The soil management systems showed differential capacity of P accumulation. In the areas under no-tillage, P is accumulated in the toplayer and drastically reduced with depth, while in CS, this reduction is less pronounced. In the 0-20 cm depth layer during the adopted period of the no-tillage system, it was observed an increase in the content of inorganic phosphorus extracted by resin and 0.5 M NaHCO3 (PiAER and PiBIC) and organic phosphorus extracted by 0.5 M NaHCO3 (PoBIC), fractions considered as available for Biomass. Regardless of the year of adoption, the no-tillage system was superior to CS and NF. This was also observed for the inorganic and organic fractions extracted by NaOH 0.1M (PiHid-0.1 and PoHid-0.1)and inorganic fraction extracted by HCl 1M (PiHCl).

Deep Inorganic Fraction Characterization of PM10, PM2.5, and PM1 in an Industrial Area Located in Central Italy by Means of Instrumental Neutron Activation Analysis

Atmospheric pollution is an important task in life sciences and, in particular, inorganic fraction characterization is considered as an important issue in this field. For many years, researchers have focused their attention on the particulate matter fraction below 10 μm: in this case, our attention was also focused on PM2.5 (i.e., particles with a size fraction smaller than 2.5 μm) and PM1 (below 1 μm). This paper would like to investigate whether the element accumulation in different granulometric fractions is similar, or whether there are behavior dissimilarities. Among the different analytical techniques, the instrumental neutron activation analysis, an instrumental nuclear method, was used for its peculiarity of investigating the sample without performing any chemical-physical treatment. Forty-two daily samples using the reference method were collected, 15 filters for PM10, 18 for PM2.5, and 12 for PM1; the filters, along with primary standards and appropriate standard reference materials, were irradiated at the National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) R.C.-Casaccia’s Triga MARK II reactor. The irradiations carried out in the Rabbit and Lazy Susan channels allowed for the investigation of 36 elements and the relative Pearson’s correlations between elements and PM-fractions (PM10 vs. PM2.5 was good, whereas PM10 vs. PM1 was the worst). The Enrichment Factors were studied for the three fractions to show how anthropogenic sources have affected the element content. A comparison between these data and element levels determined worldwide showed that our concentrations were lower than those determined in similar scenarios. Furthermore, a statistical approach (source discrimination, hierarchical cluster analysis, principal component analysis) has allowed us to identify similarities between the samples: the airborne filters can be divided in two main groups (i.e., one made of PM10 and PM2.5 filters and one only of PM1 filters), meaning a different element contribution to this fraction coming from other sources present at the site.

Source Apportionment of Fine Organic and Inorganic Atmospheric Aerosol in an Urban Background Area in Greece

Fine particulate matter (PM) originates from various emission sources and physicochemical processes. Quantification of the sources of PM is an important step during the planning of efficient mitigation strategies and the investigation of the potential risks to human health. Usually, source apportionment studies focus either on the organic or on the inorganic fraction of PM. In this study that took place in Patras, Greece, we address both PM fractions by combining measurements from a range of on- and off-line techniques, including elemental composition, organic and elemental carbon (OC and EC) measurements, and high-resolution Aerosol Mass Spectrometry (AMS) from different techniques. Six fine PM2.5 sources were identified based on the off-line measurements: secondary sulfate (34%), biomass burning (15%), exhaust traffic emissions (13%), nonexhaust traffic emissions (12%), mineral dust (10%), and sea salt (5%). The analysis of the AMS spectra quantified five factors: two oxygenated organic aerosols (OOA) factors (an OOA and a marine-related OOA, 52% of the total organic aerosols (OA)), cooking OA (COA, 11%) and two biomass burning OA (BBOA-I and BBOA-II, 37% in total) factors. The results of the two methods were synthesized, showcasing the complementarity of the two methodologies for fine PM source identification. The synthesis suggests that the contribution of biomass burning is quite robust, but that the exhaust traffic emissions are not due to local sources and may also include secondary OA from other sources.

Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics: Insights from the Morteratsch glacier (Swiss Alps)

Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the radionuclides detected in our samples, we have identified 108mAg, an artificial species which has never been observed in terrestrial environments before. This finding supports that cryoconite has an extraordinary ability to accumulate radioactivity. Our results also show that the radioactivity of cryoconite from a single glacier is far from uniform. Both the absolute amount of radioactivity and the relative contribution of single radionuclides are highly variable in samples from the Morteratsch glacier. To investigate the processes responsible for such variability, we have explored the correlation between radionuclides, organic and inorganic carbon fractions and the morphological features of cryoconite deposits. We have found that the degree of connection between cryoconite and supraglacial hydrology is particularly important, since it strongly influences the accumulation of radionuclides in cryoconite. Cryoconite holes connected with supraglacial channels are rich in cosmogenic 7Be; in contrast, poorly connected deposits are rich in artificial fallout radionuclides and elemental carbon. The very different half-lives of 7Be and artificial radionuclides allowed us to discuss our findings in relation to the age and maturity of cryoconite deposits, highlighting the potential use of radionuclides to investigate hydrological supraglacial processes and material cycling at the surface of glaciers.

Responses of organic and inorganic phosphorus fractions in brown earth to successive maize stover and biochar application: a 5-year field experiment in Northeast China

To compare the effects of maize stover and its biochar on soil P fractions and investigate the effects of different stover incorporation practices (direct return or pyrolysis) on the transformation of soil P fractions after a long-term field experiment. Total P, Olsen-P, inorganic P fractions, and organic P fractions were analyzed via a 5-year field experiment growing maize. The treatments were as follows: CK0 (no fertilizer application or amendment), CK (application of mineral NPK fertilizer), ST (application of maize stover at 7.5 t ha−1 along with mineral NPK fertilizer), and BC (application of biochar at 2.63 t ha−1, a rate approximately equivalent to a maize stover biomass of 7.5 t ha−1; the biochar was charred according to a 35% output ratio in the factory). All treatments received N mineral fertilizer at 120 kg N ha−1, P mineral fertilizer at 26 kg P ha−1, and K mineral fertilizer at 50 kg K ha−1 annually. Relative to the initial fractions in 2013, biochar generally increased the inorganic P fractions (Ca8-P, Ca10-P, Al-P, and Fe-P), and maize stover generally increased the organic P fractions (MLOP, MROP, and HROP), while both maize stover and its biochar significantly decreased O-P in the soil. After 5 years (in 2017), relative to CK treatment, amendment with maize stover and its biochar increased total P and decreased Olsen-P. The total inorganic P, Ca8-P, and Fe-P were significantly increased by biochar. Ca2-P and O-P were significantly decreased by maize stover and its biochar. Total organic P was increased with maize stover and biochar amendment. LOP and HROP were significantly increased under biochar application, and all organic P fractions were significantly increased under maize stover amendment. The application of maize stover and its biochar affected both organic and inorganic phosphorus fractions; biochar had a more advantageous effect on the soil inorganic P fractions, while stover had a greater effect on the content of organic P fractions.

Reducing Acidity of Tropical Acid Soil to Improve Phosphorus Availability and Zea mays L. Productivity through Efficient Use of Chicken Litter Biochar and Triple Superphosphate

Phosphorus is a macronutrient which plays an important role in plant metabolism, growth, and development. However, in tropical acid soils, P fixation is high because of significant amounts of Al and Fe ions. Al and Fe ions can reduce diffusion of P into plant roots. Low absorption of P at initial growth of most plants causes stunting and slow growth of plant leaves. This process reduces photosynthesis. Chicken litter biochar (CLB) had been used on tropical acid soils to improve total P, available P, organic P, and inorganic fractions of P. Moreover, CLB is able to reduce exchangeable acidity, Fe, and Al ions in mineral acid soils because of the reactive surfaces of this organic amendment. However, there is dearth of information on the effects of the right combination of CLB and triple superphosphate (TSP) on the aforementioned soil chemical properties and crop productivity. To this end, the objectives of this study were to improve P: (i) Availability in a mineral acid soil and (ii) uptake, agronomic efficiency, and dry matter yield of Zea mays L. using the right amounts of TSP and CLB. Combinations of 75%, 50%, and 25% CLB (based on recommended 5 t ha−1) and TSP (based on recommended P fertilization for maize) were evaluated in a pot study. Selected soil chemical properties, maize plants nutrient uptake, growth variables, and dry matter yield were determined using standard measures. Results showed that 25% and 50% biochar of 5 t ha−1 with 75% TSP can increase soil P availability, recovery, agronomic use efficiency, and dry matter yield of maize plants. These optimum rates can also reduce P fixation by Al and Fe ions. Therefore, soil and maize productivity can be improved by using CLB (25% and 50% of 5 t ha−1) and TSP (75% of conventional rate) to increase nutrients availability especially P.