Search results for "Enrichment factor"
showing 10 items of 23 documents
Characterization of the Etna volcanic emissions through an active biomonitoring technique (moss-bags): Part 1 – Major and trace element composition
2013
Active biomonitoring using moss-bags was applied to an active volcanic environment for the first time. Bioaccumulation originating from atmospheric deposition was evaluated by exposing mixtures of washed and air-dried mosses (Sphagnum species) at 24 sites on Mt. Etna volcano (Italy). Concentrations of major and a large suite of trace elements were analysed by inductively coupled mass and optical spectrometry (ICP-MS and ICP-OES) after total acid digestion. Of the 49 elements analysed those which closely reflect summit volcanic emissions were S, Tl, Bi, Se, Cd, As, Cu, B, Na, Fe, Al. Enrichment factors and cluster analysis allowed clear distinction between volcanogenic, geogenic and anthropo…
Heavy metals in coastal water systems. A case study from the northwestern Gulf of Thailand.
2005
A geochemical survey of the northwestern part of the Thailand Gulf (Inner Gulf) was carried out in order to define concentrations and distribution patterns of selected heavy metals (V, Cr, Co, Ni, Cu, Zn, and U) in the coastal system and estuarine area of the Mae Klong river. The results indicate the presence of two different sources of heavy metals in the studied environment and allowed us to identify a lithogenic component that significantly influences the composition of coastal waters and suspended particulate matter (SPM). Comparison of the normalized heavy metals concentrations both in the studied samples and in those reported for the Sn–W ores present in the surrounding areas suggests…
Accumulation of trace metals in sediments in a Mediterranean Lagoon: Usefulness of metal sediment fractionation and elutriate toxicity assessment.
2015
International audience; The authors investigated sediment quality in Bizerte Lagoon (Tunisia) focusing on geochemical characteristics, metal sediment fractionation and elutriate toxicity assessment. Nickel, Cu, Zn, Pb, Cr and Cd partitioning in sediments was studied; accumulation and bioavailability were elucidated using enrichment factors, sequential extractions, redox potential, acid volatile sulfide and biotest procedures in toxicity evaluation. Results revealed an accumulation for Pb and Zn, reaching 99 and 460 mg kg−1 respectively. In addition, the acid volatile sulfide values were high in both eastern and western lagoon areas, thus affecting metal availability. Mean enrichment factor …
Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography–tandem mass spe…
2017
A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) and salting-out assisted liquid–liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75–120%) and precision (RSD values ≤ 16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the…
Determination of urea-derived pesticides in fruits and vegetables by solid-phase preconcentration and capillary electrophoresis
2001
A multiresidue analytical method based on solid-phase extraction (SPE) enrichment combined with capillary electrophoresis (CE), using micellar electrokinetic capillary chromatography (MEKC), was developed to determine ten substituted urea pesticides in orange and tomato samples. Several factors such as pH, composition and concentration of the buffer, concentration of surfactant, addition of organic solvent, and working voltage were optimized to obtain the best compound separation in the shortest time. Separation can be achieved in 7 min using a micellar aqueous pH 9 buffer composed of 4 mM borate and 35 mM sodium dodecyl sulfate. After an SPE procedure, which provided a 10-fold enrichment, …
Atmospheric Mineral Dust - Properties and Source Markers
1989
Mineral dust particles from arid regions of the earth are a substantial fraction of the atmospheric aerosol. Due to long range transport mineral dust is found in all types of airmasses and thus in remote regions too. Physical and chemical properties allow to distinguish mineral aerosols easily from other types of aerosols. Many characteristic features are similar to those of global average crust. Only major deviations from this mean composition are reflected by the mineral aerosol composition. In order to derive source characteristic features from mineral dust samples advanced statistical methods coupled with various analytical tools from the mineralogy and chemistrymust be applied.
Bioavailability and assessment of heavy metal pollution in sediment cores off the Mejerda River Delta (Gulf of Tunis): How useful is a multiproxy app…
2016
International audience; Three core samples were taken from zones offshore from the Mejerda River Delta (Tunisia) and analyzed formajor and trace elements to assess their relationships with organic matter, monosulfides and carbonates, aswell as for pollution and bioavailability. Chemical speciation,ΣSEM/AVS, the enrichment factor (EF) and thegeo-accumulation index (I-geo) were used. Iron, cadmium, lead and zinc – the most frequently mined metalsin the Mejerda catchment – were found as contaminants in the offshore areas. Estimations of trace elementaccumulation using the EF and the I-geo index show that lead, and to a lesser extent zinc, are the most pollutingmetals off the Mejerda outlet. Ac…
Pollution assessment of heavy metals in soils of India and ecological risk assessment: A state-of-the-art
2019
Soil is substantive component of biosphere, which is exposed to plethora of pollutants including heavy metals. These are added by natural as well as anthropogenic activities. Upsurge in heavy metal content affects all organisms by biomagnification. So, it becomes vital to create a database of heavy metals concentration in soil. This is relevant in countries where unsustainable intensive agriculture, industrial and urban development is in progress. The present review of the scientific literature from 1991 to 2018 on heavy metals in soils in India shows that Zn and Pb exceeded their limits for Indian natural soil guidelines (Zn 22.1 and Pb 13.1 μg/g), Canada (Zn 200 μg/g), Swedish (80 μg/g) a…
Potentially toxic elements in fen peatland soils located near lignite-fired power plants in Central Poland
2021
Abstract The Grojec Valley (GV) peatland area in Central Poland is located close to lignite-fired power plants, which could be sources of potentially toxic elements (PTE). The aims of this study are: (1) to determine the effect of the lignite-fired power plants on soil pollution, (2) to evaluate pollution indices and magnetic susceptibility methods for determining the origin and distribution of PTE in soils, and (3) to demonstrate the importance of appropriate geochemical background (GB) selection for pollution studies in peatland soils. In order to comprehensively assess the soil pollution, four pollution indices (calculated using various types of GBs), and the mass-specific magnetic susce…
Distribution of Heavy Metals in Marine Sediments of Palermo Gulf (Sicily, Italy)
2008
Concentrations of Cr, Cu, Hg, Pb and Zn have been measured, by atomic absorption spectrophotometry, in the fine fraction (<63 μm) of surface sediments collected in 30 sites in the Palermo Gulf (Sicily, Italy) in order to assess the levels and the spatial distribution of these elements. Enrichment factors calculated with respect to clean areas have been considered to discriminate between levels due to background or to pollution contributions. The sampling stations, which form a grid inside these areas, are characterized by geographic proximity and by the presence of pollution sources. Ratio matching technique along with hierarchical clustering, minimum spanning tree and principal component a…