Enhanced Polonium Concentrations in Aerosols from the Gulf Oil Producing Region and the Role of Microorganisms

This study provides the first data set of 210Po and 210Pb activity concentrations in the organic and inorganic components of several particle size classes of aerosols collected at two sampling stations in Kuwait. The 210Po concentrations in the aerosols (Bq/g) were similar in all of the particle size classes, but as most (91%) of the aerosol load was made of fine fraction particles of PM0.39–2.5 µm, most of the 210Po activity was carried by this aerosol fraction. At the two sampling stations, the 210Po/210Pb activity concentration ratios in the aerosols were similar, stable around the year, and averaged 1.5 (range 1.2–1.9), much higher than the typical activity concentration ratios of these radionuclides in unmodified (background) aerosols, with Po/Pb < 0.1. The aerosol enrichment in 210Po was likely originated from the oil industry, specifically by gas flaring and oil refining in the Gulf region. Radionuclide analysis in the organic and inorganic components of aerosols showed that the 210Po concentration in the organic component was one order of magnitude higher than the 210Po concentration in the inorganic component, in contrast with 210Pb, which displayed similar concentrations in both organic and inorganic aerosol components. The 210Po carrying organic component of aerosols was investigated and it was found to be largely composed of microorganisms with high microbial and fungi diversity, with the phyla Proteobacteria, Ascomycota, and Basidiomycota being dominant among the bacteria and with Zygomycota being dominant among the fungi. Therefore, we are facing an active concentration process of the atmospheric 210Po carried out by microorganisms, which underlies the 210Po enrichment process in the organic component of aerosols. This bioconcentration of polonium in bioaerosols was unknown.

Sampling and analysis of coarsely shredded mixed commercial waste. Part II: particle size-dependent element determination

In contemporary waste management, sampling of waste is essential whenever a specific parameter needs to be determined. Although sensor-based continuous analysis methods are being developed and enhanced, many parameters still require conventional analytics. Therefore, sampling procedures that provide representative samples of waste streams and enable sufficiently accurate analysis results are crucial. While Part I estimated the relative sampling variabilities for material classes in a replication experiment, Part II focuses on relative sampling variabilities for 30 chemical elements and the lower heating value of the same samples, i.e., 10 composite samples screened to yield 9 particle size classes (< 5 mm–400 mm). Variabilities < 20% were achieved for 39% of element-particle size class combinations but ranged up to 203.5%. When calculated for the original composite samples, variabilities < 20% were found for 57% of the analysis parameters. High variabilities were observed for elements that are expectedly subject to high constitutional heterogeneity. Besides depending on the element, relative sampling variabilities were found to depend on particle size and the mass of the particle size fraction in the sample. Furthermore, Part I and Part II results were combined, and the correlations between material composition and element concentrations in the particle size classes were interpreted and discussed. For interpretation purposes, log-ratios were calculated from the material compositions. They were used to build a regression model predicting element concentration based on material composition only. In most cases, a prediction accuracy of ± 20% of the expected value was reached, implying that a mathematical relationship exists.

Redox-driven changes in the distribution of Fe minerals between aggregate-size classes in illuvial and elluvial horizons of a hydromorphic soil

&lt;div&gt; &lt;p&gt;&lt;span&gt;Paddy soils experience long-term redox alternations affecting the interactions between the biogeochemical cycling of iron (Fe) and carbon (C). Although the higher soil organic matter (SOM) accumulation rates in paddy topsoils with respect to non-paddy soils is generally assumed to be due to limited mineralization under anoxic soil conditions resulting from frequent field flooding, there is growing evidence questioning this assumption. Moreover, differences in particle aggregation and SOM turnover are likely to both affect and be affected by the trajectory of Fe mineral evolution/crystallinity with redox fluctuations. We hypothesized that redox cycling in paddy soils will affect the particle aggregation, the distribution and mineralogy Fe (hydr)oxides between aggregate size fractions, and consequently the mechanisms of SOM stabilization. In particular, we expect finer aggregate and particle size classes to have a higher proportion of short-range ordered (SRO) Fe oxides with respect to larger aggregates under paddy management, compared to non-paddy management, and that paddy management can result in lower amounts of Fe(hydr)oxides in the topsoil with respect to non-paddy soils. &lt;/span&gt;&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;We tested these hypotheses by evaluating mineralogical changes, and the distribution of Fe species and organic C between different aggregate and particle-size fractions in topsoil (eluvial) and subsoil (illuvial) horizons of soils under long-term paddy (P) horizons (Arp1, Arp2, Arpd, Brd1, Brd2) and non-paddy (NP) horizons (Ap1, Ap2, Bgw) in NW Italy. Soil aggregates (microaggregates: &lt;200&amp;#160;&lt;/span&gt;&lt;span&gt;&amp;#956;&lt;/span&gt;&lt;span&gt;m, free silt: (53-2 &lt;/span&gt;&lt;span&gt;&amp;#956;&lt;/span&gt;&lt;span&gt;m), free clay: &lt;2 &lt;/span&gt;&lt;span&gt;&amp;#956;&lt;/span&gt;&lt;span&gt;m, and, after sonication, fine sand, silt and clay within microaggregates) have been obtained from&lt;/span&gt;&lt;span&gt;bulk soils using an aggregate and particle size physical fractionation method. After fractionation, Fe phases were evaluated by selective extraction procedures, X-ray diffraction (XRD) and Fe K-edge extended X-ray fine structure (Fe EXAFS) spectroscopy (Elettra XAFS beamline). &lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;Our results indicate: (1) a &lt;span&gt;depletion in the contents of ferrihydrite in the P topsoil horizons with respect to NP, though redox cycling favoured an increase in ferrihydrite in the P subsoil, possibly due to Fe(II) translocation from topsoil to subsoil, with consequent ferrihydrite precipitation and aggregates formation; &lt;/span&gt;(2) more crystalline Fe mineral phases were associated with intra-aggregate clay fraction in the P topsoil&lt;span&gt;. In the clay fraction in the Brd2 subsoil horizon &lt;/span&gt;magnetite was observed. &lt;span&gt;In the NP soil the illuvial horizons were not characterized by a significant increase in ferrihydrite. Our hypothesis that finer aggregate and particle size classes have a higher proportion of SRO Fe oxides with respect to larger aggregates under P management, with respect to NP management,&amp;#160;&lt;/span&gt;was confirmed; (3) more organic C was associated with the fine fraction in P with respect to NP suggesting that redox cycling enhances the chemical stabilization of mineral-associated SOM.&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;These findings focused on localized Fe dynamics and biogeochemical coupling with SOM, suggesting that &lt;span&gt;redox-driven changes in aggregate-size classes distribution were also linked to the differences in organic C and Fe stocks in these two agro-ecosystems.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;

Distribution-Independent Empirical Modeling of Particle Size Distributions—Coarse-Shredding of Mixed Commercial Waste

Particle size distributions (PSDs) belong to the most critical properties of particulate materials. They influence process behavior and product qualities. Standard methods for describing them are either too detailed for straightforward interpretation (i.e., lists of individual particles), hide too much information (summary values), or are distribution-dependent, limiting their applicability to distributions produced by a small number of processes. In this work the distribution-independent approach of modeling isometric log-ratio-transformed shares of an arbitrary number of discrete particle size classes is presented. It allows using standard empirical modeling techniques, and the mathematically proper calculation of confidence and prediction regions. The method is demonstrated on coarse-shredding of mixed commercial waste from Styria in Austria, resulting in a significant model for the influence of shredding parameters on produced particle sizes (with classes: > 80 mm, 30–80 mm, 0–30 mm). It identifies the cutting tool geometry as significant, with a p-value < 10–5, while evaluating the gap width and shaft rotation speed as non-significant. In conclusion, the results question typically chosen operation parameters in practice, and the applied method has proven to be valuable addition to the mathematical toolbox of process engineers.

Data on the elemental composition (mobile fractions and total content) of soils in catena at the SE Valdai Hills, Russia

This study presents a dataset on seasonal soils sampling from September 2016 to May 2018 in the southern part of the Central Forest Reserve (SE Valdai Hills) within a catena with Endocalcaric Albic Glossic Stagnic Profondic Retisols (Cutanic, Loamic) and Albic Gleyic Histic Retisols (Cutanic, Loamic) under coniferous-deciduous forest (Tília cordáta, Pícea ábies, Ácer platanoídes) on loess-like loams underlain by carbonate moraine deposits. 152 soil samples were taken to define total concentration of 67 chemical elements (ChEs), content of three mobile fractions (exchangeable, bound within organo-mineral complexes, bound with Fe and Mn hydroxides) of 69 ChEs and content of residual fraction, including macro elements (Al, Ca, Fe, K, Mg, Mn, Na, P, Ti, S, Si), heavy metals (Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, Th, U, V, Zn), trace elements (Ag, As, B, Be, Bi, Br, Cd, Cs, Ge, Hf, Li, Mo, Nb, Pd, Sb, Sc, Se, Sn, Ta, Te, Tl,W, Zr) and rare earth elements (Ce, Er, Eu, Gd, La, Lu, Nd, Pr, Sm, Tb, Tm, Dy, Ho, Y, Yb). We measured pH-value, total organic carbon content (TOC), seven particle-size classes (

Concentrations, ratios, and sinking fluxes of major bioelements at Ocean Station Papa

Fluxes of major bioelements associated with sinking particles were quantified in late summer 2018 as part of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign near Ocean Station Papa in the subarctic northeast Pacific. The thorium-234 method was used in conjunction with size-fractionated (1–5, 5–51, and &gt;51 μm) concentrations of particulate nitrogen (PN), total particulate phosphorus (TPP), biogenic silica (bSi), and particulate inorganic carbon (PIC) collected using large volume filtration via in situ pumps. We build upon recent work quantifying POC fluxes during EXPORTS. Similar remineralization length scales were observed for both POC and PN across all particle size classes from depths of 50–500 m. Unlike bSi and PIC, the soft tissue–associated POC, PN, and TPP fluxes strongly attenuated from 50 m to the base of the euphotic zone (approximately 120 m). Cruise-average thorium-234-derived fluxes (mmol m–2 d–1) at 120 m were 1.7 ± 0.6 for POC, 0.22 ± 0.07 for PN, 0.019 ± 0.007 for TPP, 0.69 ± 0.26 for bSi, and 0.055 ± 0.022 for PIC. These bioelement fluxes were similar to previous observations at this site, with the exception of PIC, which was 1 to 2 orders of magnitude lower. Transfer efficiencies within the upper twilight zone (flux 220 m/flux 120 m) were highest for PIC (84%) and bSi (79%), followed by POC (61%), PN (58%), and TPP (49%). These differences indicate preferential remineralization of TPP relative to POC or PN and larger losses of soft tissue relative to biominerals in sinking particles below the euphotic zone. Comprehensive characterization of the particulate bioelement fluxes obtained here will support future efforts linking phytoplankton community composition and food-web dynamics to the composition, magnitude, and attenuation of material that sinks to deeper waters.

Attainable Region Approach in Analyzing the Breakage Behavior of a Bed of Olivine Sand Particles: Optimizing Impact Energy and Particle Size

In this study, we investigated the breakage behavior of a bed of olivine sand particles using a drop-weight impact test, with drop weights of various shapes (oval, cube, and sphere). An Attainable Region (AR) technique, which is a model-free and equipment-independent technique, was then applied to optimize the impact energy during the breakage process and also to get particles in defined particle size classes. The findings revealed that the different drop weights produce products within the three different particle size classes (feed, intermediate, and fine). A higher mass fraction of materials in the fine-sized class (−75 μm) was obtained when the spherical drop weight was used relative to the cubic and oval drop weights. The drop height was found to have a significant influence on the breakage process. The AR technique proved to be a practical approach for optimizing impact energy and particle size during the breakage of a bed of olivine particles, with potential application in sustainable soil stabilization projects.

Valorization of MSWI Bottom Ash as a Function of Particle Size Distribution, Using Steam Washing

Treatments to reduce the leaching of contaminants (chloride, sulfate, heavy metals) into the environment from bottom ash (BA) are investigated, as a function of the ash’s particle size (s). The aim is to make BA suitable for reuse as secondary raw material, in accordance with the legal requirements. Such treatments must be economically feasible and, possibly, have to use by-products of the plant (in this case, steam in excess from the turbine). For the sake of completeness and comparison, carbonation is performed on those BA particle size classes that are not positively responsive to steam washing. BA is partitioned into four different particle size classes (s ≥ 4.75, 4.75 > s ≥ 2, 2 > s ≥ 1 and s < 1 mm, corresponding to 36, 24, 13 and 27 wt%, respectively). In the case of s ≥ 2 mm (60 wt%), steam washing is effective in reducing to under the legal limits the leaching of chlorides, sulfate and heavy metals (Zn, Cu, Cd, Pb). It has been observed that steam washing causes both removal and dissolution of thin dust adherent to the BA’s surface. BA with 2 > s ≥ 1 (~13 wt% of total BA) requires a combination of steam washing and carbonation to achieve a leaching below the legal limits. The finest BA fraction, s < 1 mm (~27 wt% of total BA), is treated by carbonation, which reduces heavy metals leaching by 85%, but it fails to sufficiently curb chlorides and sulfates.

Carbon flows by soil organic matter formation: A review based on 13C natural abundance

&lt;p&gt;Aggregation of mineral and organic particles is a key process of soil development, which promotes carbon (C) stabilization by hindering decomposition of plant and microbial residues. All microbial utilization and C stabilization processes lead to &lt;sup&gt;13&lt;/sup&gt;C fractionation and consequently to various &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values of organic matter in aggregate size classes, sand, silt, and clay-sized particles, as well as density fractions. Differences in &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C within the aggregates and density fractions may have two reasons: 1) preferential stabilization of organic compounds with light or heavy &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C and/or 2) stabilization of organic materials after passing one or more microbial utilization cycles, leading to respiring of &lt;sup&gt;13&lt;/sup&gt;C depleted CO&lt;sub&gt;2&lt;/sub&gt; and heavier &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C in remaining C. Assuming these two reasons, the new approach based on the natural differences in stable C isotopic composition between SOM fractions was proposed and tested on soils developed solely under C3 vegetation (arable, coniferous and deciduous forests) in boreal climate (Gunina and Kuzyakov, 2014). This approach assumes that: 1) &lt;sup&gt;13&lt;/sup&gt;C enrichment between the SOM fractions corresponds to successive steps of SOM formation; 2) &lt;sup&gt;13&lt;/sup&gt;C fractionation (but not the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C signature) depends mainly on the transformation steps and not on the C precursors. Consequently, &lt;sup&gt;13&lt;/sup&gt;C enrichment of SOM fractions allows reconstructing the SOM formation pathways. To prove these initial results we reviewed&amp;#160; &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values of soils globally and focused on the i) estimation of the validity of this approach for soils developed under various climatic conditions and parent materials, and depending on fertilization, and ii) C flows not only between aggregate size classes and density fractions but also between various particle size classes of the soils (i.e. sand, silt, and clay) and iii) on revealing the intensities of natural &lt;sup&gt;13&lt;/sup&gt;C fractionation during the stabilization of litter C in aggregates, particle size classes, and density fractions. Results showed that density fractions were &lt;sup&gt;13&lt;/sup&gt;C enriched in the order: free particulate organic matter (POM) &lt; light occluded POM &lt; heavy occluded POM &lt; mineral fraction, with the strongest increase between the light occluded and heavy occluded POM. The maximum &lt;sup&gt;13&lt;/sup&gt;C fractionation during stabilization of litter C in density fractions and aggregate size classes was &lt; 2&amp;#8240;. &amp;#916;&lt;sup&gt;13&lt;/sup&gt;C enrichment of the SOM fractions showed that the main direction of C flows within the aggregates and SOM fractions was from the macroaggregate-free POM to the mineral microaggregate fraction. Thus, despite some limitations, &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C natural abundance approach based on &lt;sup&gt;13&lt;/sup&gt;C fractionation within individual steps of SOM formation is very useful and probably the sole approach to estimate C flows under steady-state without labeling.&lt;/p&gt;

Methods for the analysis of asbestos in incoherent soils

&lt;p&gt;Soils contaminated with asbestos, whether of natural origin or deriving from anthropogenic pollution, can have very different dimensional, chemical and humidity characteristics.&lt;/p&gt;&lt;p&gt;The legal limit that allows to define an asbestos contaminated soil is a concentration of 1000 mg / kg of asbestos fibers, as per DLGS 152/2006. The analytical methods suggested in Italy by regulation (DM 6/09/94) for the determination of asbestos content are Diffrattometry (XRD) and &amp;#160;Fourier Transform Infrared (FTIR), methods that do not allow to distinguish the fibrous material and secondly Scanning Electron Microscopy (SEM). The Phase Contrast Optical Microscopy (PCOM) is considered a methodology only useful for a qualitative analysis for it low rilevability index (0,1 mm in respect of&amp;#160;&amp;#160; for SEM and&amp;#160;&amp;#160;&amp;#160; for XRD and FTIR).&lt;/p&gt;&lt;p&gt;The goal of this study is to describe the cheap and quick soil analysis methodology used in the Asbestos laboratory of DIATI Politecnico di Torino where also the representativeness of the analysed quantity of material is considered.&lt;/p&gt;&lt;p&gt;When the sample is an incoherent soil, sieving (at 0.6 - 0.3 &amp;#8211; 0.150-0.075 mm) after drying is carried out. The asbestos fibers eventually present in the classes &gt;0.6 mm and 0.6-0.3 mm, that are visible with a low magnification (5-10 x), can be recovered by flotation and weighted after drying. The quantitative analysis of the classes 0.3-0.075 is perfomed by means of PCOM, measuring the dimensions of the fibers, hipotyzing the third dimension equal to the width and calculating the weight knowing the density of the asbestos fiber observed. &amp;#160;.The presence of asbestos in the finer particle size class can be verified by SEM, but is the asbestos content in the other particle size classes is high the value obtained for the finer class is generally found to be irrelevant to the final result.If the initial sample has a very fine particle size, it is homogenized by grinding and is prepared for reading under the SEM by depositing a known quantity on a polycarbonate membrane. The results thus obtained are referred to the analysis of at least 100 g of material.&lt;/p&gt;&lt;p&gt;The reliability of the technique has been verified by participating in interlaboratory circuits.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;