scholarly journals What the presence of regulated chemical elements in beached lacustrine plastics can tell us: the case of Swiss lakes

2021 ◽  
Vol 193 (11) ◽  
Author(s):  
Montserrat Filella ◽  
Juan-Carlos Rodríguez-Murillo ◽  
Andrew Turner
Keyword(s):  
Polyvinyl Chloride ◽  
Flame Retardants ◽  
Chemical Elements ◽  
Fluorescence Spectrometry ◽  
Lake Geneva ◽  
Plastic Pollution ◽  
X Ray ◽  
Management Schemes ◽  
Standing Stocks ◽  
Insight Into

AbstractPlastics (n = 3880) have been sampled from 39 beaches of ten Swiss lakes of varying sizes, hydrodynamics, and catchments, with a selection (n = 598) analysed for potentially hazardous (and regulated) chemical elements (As, Ba, Br, Cd, Cr, Hg, Pb, Sb, Se) by X-ray fluorescence spectrometry. Plastic objects and fragments with identifiable or unidentifiable origins were present on all beaches surveyed, and were often most abundant in proximity to major riverine inputs. Chemical elements were detected in between two (Hg) and 340 (Ba) samples with maximum concentrations exceeding 2% by weight for Ba, Cd, Cr, Pb, and Sb. Inter-element relationships and characteristics of the samples suggest that elements are largely present as various additives, including pigments (e.g., Cd2SSe, PbCrO4), stabilizers (in polyvinyl chloride), and flame retardants (Br). Observations are similar to, and complement, those previously reported in Switzerland’s largest lake (Lake Geneva). Comparison of concentrations of targeted chemical elements in beached plastic with currently used plastics illustrate the interest of these types of measurements in providing an insight into the persistence of plastics in standing stocks and in lakes. This information could help to introduce management schemes that consider whether plastic pollution is new or old and act accordingly.

scholarly journals Detection and Evaluation of metals in soil under influence of mining by Dispersive Energy X-ray Fluorescence Spectrometry (EDXRF), Lavras do Sul/RS

2018 ◽  
Vol 40 ◽  
pp. 70
Author(s):  
Cristiane Heredia Gomes ◽  
Diogo Gabriel Sperandio ◽  
Rafael Lima Dessart ◽  
Dionatan Daniel Giusti
Keyword(s):  
Chemical Elements ◽  
Primary Source ◽  
Soil Samples ◽  
Fluorescence Spectrometry ◽  
Natural Environments ◽  
Metallic Elements ◽  
Environmental Liabilities ◽  
X Ray ◽  
High Concentrations ◽  
The Right

Rocks are the primary source of chemical elements found in the earth. Among them metallic elements, which are distributed in most natural environments and their distribution in soils is widespread. Knowledge of the soil chemical composition will provide subsidies for a prediction of phytotoxicity and possible groundwater contamination. Concentrations of metals, in the right quantities, are essential for maintaining life. Although, if in high quantities (toxicity), can cause damage to plants, animals, and humans. This work consists of a chemical analysis of soil samples in the region of Lavras do Sul / RS, where mineral deposits occur. Until the year 1981 mining activities occupied the area without municipality, resulting in ore and waste deposits at inappropriate places, generating environmental liabilities, contributing to soil chemistry, and consequently affecting public health. Through the energy dispersive X-ray fluorescence spectrometry (EDXRF) method, 20 soil samples were analyzed in two profiles surrounding the municipality. Among them, high concentrations of Zn, Cu, Ce and Cd were detected, possibly contributing to anthropic activities and seasonal fluctuations.

Quantitative Analysis Of X-Ray Images From Geological Materials

1990 ◽  
Vol 48 (2) ◽  
pp. 244-245
Author(s):  
J. M. Paque ◽  
R. Browning ◽  
P. L. King ◽  
P. Pianetta
Keyword(s):  
Quantitative Analysis ◽  
Bulk Composition ◽  
Principal Component ◽  
Analytical Description ◽  
Bulk Sample ◽  
Geological Samples ◽  
X Ray ◽  
Software And Hardware ◽  
And Storage ◽  
Insight Into

Geological samples typically contain many minerals (phases) with multiple element compositions. A complete analytical description should give the number of phases present, the volume occupied by each phase in the bulk sample, the average and range of composition of each phase, and the bulk composition of the sample. A practical approach to providing such a complete description is from quantitative analysis of multi-elemental x-ray images.With the advances in recent years in the speed and storage capabilities of laboratory computers, large quantities of data can be efficiently manipulated. Commercial software and hardware presently available allow simultaneous collection of multiple x-ray images from a sample (up to 16 for the Kevex Delta system). Thus, high resolution x-ray images of the majority of the detectable elements in a sample can be collected. The use of statistical techniques, including principal component analysis (PCA), can provide insight into mineral phase composition and the distribution of minerals within a sample.

X-ray mapping without STEM

1994 ◽  
Vol 52 ◽  
pp. 508-509
Author(s):  
Judith M. Brock ◽  
Max T. Otten
Keyword(s):  
Life Science ◽  
Materials Science ◽  
Chemical Elements ◽  
Full Description ◽  
Scanning System ◽  
Elemental Distribution ◽  
X Ray ◽  
Transmission Electron ◽  
Distribution Of Elements ◽  
Made In

A knowledge of the distribution of chemical elements in a specimen is often highly useful. In materials science specimens features such as grain boundaries and precipitates generally force a certain order on mental distribution, so that a single profile away from the boundary or precipitate gives a full description of all relevant data. No such simplicity can be assumed in life science specimens, where elements can occur various combinations and in different concentrations in tissue. In the latter case a two-dimensional elemental-distribution image is required to describe the material adequately. X-ray mapping provides such of the distribution of elements.The big disadvantage of x-ray mapping hitherto has been one requirement: the transmission electron microscope must have the scanning function. In cases where the STEM functionality – to record scanning images using a variety of STEM detectors – is not used, but only x-ray mapping is intended, a significant investment must still be made in the scanning system: electronics that drive the beam, detectors for generating the scanning images, and monitors for displaying and recording the images.

Copper–oxygen Dynamics in Tyrosinase

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Sachiko Yanagisawa ◽  
Minoru Kubo ◽  
Genji Kurisu ◽  
Shinobu Itoh
Keyword(s):  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Active Form ◽  
Copper Ion ◽  
Atomic Resolution ◽  
Oxygen Species ◽  
X Ray ◽  
Oxygen Dynamics ◽  
Insight Into ◽  
Copper Centre

To unveil the activation of dioxygen on the copper centre (Cu<sub>2</sub>O<sub>2</sub>core) of tyrosinase, we performed X-ray crystallograpy with active-form tyrosinase at near atomic resolution. This study provided a novel insight into the catalytic mechanism of the tyrosinase, including the rearrangement of copper-oxygen species as well as the intramolecular migration of copper ion induced by substrate-binding.<br>

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