Water content and metal pollution dynamics in the surface layer of urban soils: first results of the PROFILES project

2021 ◽  
Author(s):  
Martina Siena ◽  
Marco Peli
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Urban Soils ◽  
Soil Column ◽  
Water Dynamics ◽  
Ferroalloy Production ◽  
Chemical Extraction ◽  
Time Range ◽  
X Ray ◽  
First Results

<p>This work presents the first results obtained in the context of the PROFILES project. The main objective of PROFILES concerns the identification of a possible correlation between water content dynamics and the distribution of metal pollutants in the surface layer of urban soils.</p><p>The research activity combined experimental, analytical and numerical approaches. Field activity was conducted in Bagnolo Mella, (Brescia, Northern Italy) where a ferroalloy industry operated for more than forty years (1974-2015). Four sites within the study area, at different radial distances and up/downwind with respect to the plant, have been considered. At these sites, the distribution of As, Cu, Fe, Mn, Ni, Pb, Zn concentrations in the surface soil was inferred by means of a portable X-Ray Fluorescence device. A tension infiltrometer allowed to estimate the local value of hydraulic conductivity at saturation, K<sub>s</sub>. Physico-chemical properties evaluated on soil samples via laboratory analysis were found to be rather homogeneous. However, metal concentrations were remarkably different at the four sites, larger values being detected up-wind and closer to the production plant, within the top layer (≈ 20 cm) of the soil column. In particular, sequential chemical extraction processes and X-ray Absorption Near Edge Spectroscopy showed that Mn exceeded considerably typical background levels and was present in a hybrid form of magnetite (Fe, Mn)<sub>3</sub>O<sub>4</sub>, resistant to acid dissolution. Considering that it is difficult to form Mn-substituted magnetite in surface layers at low temperatures, its presence indicates this pollutant as a by-product of ferroalloy production transported by water along the soil column. Numerical simulations with the HYDRUS 1D software have been performed to model water dynamics along the uppermost 6 meters of soil at the investigated sites, over a time range of 4 years (2013–2016). A homogeneous domain, with a constant K<sub>s</sub> value measured in the field for the top layer, has been compared against a heterogeneous case, in which the distribution of lithological categories has been determined via indicator kriging, based on available stratigraphic data. Surface recharge and evapotranspiration have been estimated from meteorological data (temperature, relative humidity, precipitation, global solar radiation and wind speed) available on an hourly basis. Numerical results allowed to characterize the time evolution of the zero-flux-plane (ZFP) depth, defined as the plane separating zones with upward and downward water flux in a thoroughly wetted soil, when evaporation and drainage are simultaneously occurring. Key findings are: (i) for the whole simulated period, the ZFP oscillates between the ground surface and a maximum depth of about 20 cm, consistent with the vertical range where peak concentrations of heavy metals were found; (ii) simulations in the homogeneous and heterogeneous cases provided analogous results, highlighting the importance of the characterization of the top surface layer. </p><p>Acknowledgments: The project PROFILES was awarded the 2019 edition of the Florisa Melone Award, promoted by the Italian Hydrological Society (SII). The authors thank the SII for the support. Part of the research was carried out within the ISEIA project of the University of Brescia (grant UNBSCLE 9015).</p>

Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

2013 ◽  
Vol 58 (2) ◽  
pp. 619-624 ◽  
Author(s):  
M. Szafarska ◽  
J. Iwaszko ◽  
K. Kudła ◽  
I. Łegowik
Keyword(s):  
Surface Layer ◽  
Magnesium Alloy ◽  
Physicochemical Properties ◽  
Treatment Effectiveness ◽  
High Energy ◽  
Alloy Surface ◽  
Heat Sources ◽  
X Ray ◽  
Additional Equipment ◽  
Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

On tungstates of divalent cations (III) – Pb5O2[WO6]

2020 ◽  
Vol 235 (8-9) ◽  
pp. 311-317
Author(s):  
Stephan G. Jantz ◽  
Florian Pielnhofer ◽  
Henning A. Höppe
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Quantum Chemical ◽  
Density Functional ◽  
Divalent Cations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
First Results ◽  
Electrostatic Calculations

Abstract${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction ($P{2}_{1}/n$, $a=7.4379\left(2\right)$ Å, $b=12.1115\left(4\right)$ Å, $c=10.6171\left(3\right)$ Å, $\beta =90.6847\left(8\right)$°, $Z=4$, ${R}_{\text{int}}=0.038$, ${R}_{1}=0.020$, $\omega {R}_{2}=0.029$, 4188 data, 128 param.) and is isotypic with ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{Te}}_{6}\right]$. ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ comprises a layered structure built up by non-condensed [WO6]${}^{6-}$ octahedra and ${\left[{\text{O}}_{4}{\text{Pb}}_{10}\right]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded $n\approx 2.31$. Furthermore first results of the thermal analysis are presented.

scholarly journals Chemical Abundances of Early Type Stars

1998 ◽  
Vol 188 ◽  
pp. 224-225
Author(s):  
S. Tanaka ◽  
S. Kitamoto ◽  
T. Suzuki ◽  
K. Torii ◽  
M.F. Corcoran ◽  
...  
Keyword(s):  
Surface Layer ◽  
Stellar Wind ◽  
Nuclear Reactions ◽  
X Rays ◽  
Early Type ◽  
Chemical Abundances ◽  
X Ray ◽  
Low Metallicity ◽  
Early Type Stars

X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.

scholarly journals Reply [to “Comment on ‘Dual-energy synchrotron X ray measurements of rapid soil density and water content changes in swelling soils during infiltration’ by Patricia Garnier et al.”]

1999 ◽  
Vol 35 (11) ◽  
pp. 3589-3590 ◽  
Author(s):  
Patricia Garnier ◽  
Rafael Angulo-Jaramillo ◽  
David A. DiCarlo ◽  
Tim W. J. Bauters ◽  
Christophe J. G. Darnault ◽  
...  
Keyword(s):  
Water Content ◽  
Dual Energy ◽  
Soil Density ◽  
X Ray ◽  
Swelling Soils

scholarly journals Revegetation in abandoned quarries with landfill stabilized waste and gravels: water dynamics and plant growth – a case study

2017 ◽  
Author(s):  
Cheng-liang Zhang ◽  
Jing-jing Feng ◽  
Li-ming Rong ◽  
Ting-ning Zhao
Keyword(s):  
Plant Growth ◽  
Water Content ◽  
Robinia Pseudoacacia ◽  
Water Dynamics ◽  
Leaf Water Content ◽  
Rock Fragments ◽  
Platycladus Orientalis ◽  
Concrete Production ◽  
Uppermost Layer ◽  
Pavement Construction

Abstract. Large amounts of quarry wastes are produced during quarrying. Though quarry wastes are commonly used in pavement construction and concrete production, in-situ utilization during ecological restoration of abandoned quarries has its advantage of simplicity. In this paper, rock fragments of 2 ~ 3 cm in size were mixed with landfill stabilized waste (LSW) in different proportions (LSW: gravel, RL), which was called LGM. The water content, runoff and plant growth under natural precipitation were monitored for two years using a runoff plot experiment. LGM with a low fraction of LSW was compacted in different degrees to achieve an appropriate porosity; water dynamic and plant growth of compacted LGM were studied in a field experiment. The results showed that, (1) LGM can be used during restoration in abandoned quarries as growing material for plants. (2) RL had a significant effect on infiltration and water holding capacity of LGM, and thus influenced retention of precipitation, water condition and plant growth. LGM with RL ranging from 8 : 1 to 3 : 7 was suitable for plant growth, but the target species grew best when RL was intermediate. (3) Compaction significantly enhanced water content of LGM with a low RL of 2 : 8, but leaf water content of plants was lower or unchanged in the more compacted plots. Moderate compaction was beneficial to the survival and growth of Robinia pseudoacacia. Platycladus orientalis and Medicago sativa were not significantly affected by compaction, and they grew better under high degree of compaction which was disadvantageous for the uppermost layer of vegetation.

Soil water dynamics after fire in a Portuguese shrubland

2006 ◽  
Vol 15 (1) ◽  
pp. 99 ◽  
Author(s):  
Joaquim S. Silva ◽  
Francisco C. Rego ◽  
Stefano Mazzoleni
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Plant Community ◽  
Root Distribution ◽  
Control Plot ◽  
The Other ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Surface Layers ◽  
Before And After

This paper presents a study where soil water content (SW) was measured before and after an experimental fire in a shrubland dominated by Erica scoparia L. in Portugal. Two plots were established: one was kept as a control plot and the other was burned by an experimental fire in June 2001. Measurements were taken before fire (2000), and after fire (2001, 2002, and 2003) at six depths down to 170 cm, from June to December. Measurements before fire allowed comparison of the two plots in terms of the SW differential, using 2000 as a reference. Results for 2001 showed that SW decreased less during the drying season (June–September) and increased more during the wetting season (October–December) in the burned plot than in the control plot. The magnitude of these effects decreased consistently in 2002 and 2003, especially at surface layers. The maximum gain of SW for the total profile in the burned plot was estimated as 105.5 mm in 2001, 70.2 mm in 2002, and 35.6 mm in 2003. The present paper discusses the mechanisms responsible for the increase in SW taking into account the characteristics of the plant community, including the root distribution, and the results of other studies.

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