Quantification Of Trace Metals Research Articles

Distribution, Levels, Potential Sources and Human Health Risk Assessment of Trace Metals in Atmospheric Particulate Matter in Ogbia communities of Bayelsa State, Niger Delta, Nigeria

The occurrence of toxic metals in atmospheric particulate matter is of high risk to human health. Hence, the objective of this paper was to evaluate the distribution, concentrations, potential sources and human health risk assessment of trace metals in atmospheric particulate matter in Ogbia communities of Bayelsa State, Niger Delta, Nigeria. Samples of atmospheric particulate matter were digested using a mixture of acids, and quantification of trace metals was achieved using atomic absorption spectrophotometry (Model: Buck 230 ATS). The concentration (µg m-3) of trace metals in atmospheric particulate matter ranged as follows: Pb (<0.010 - 0.060), Cd (<0.010 - 0.880), Ni (<0.010 - 0.028), Cu (<0.010 - 0.046), Zn (<0.010 - 0.028), and Co (<0.010 - 0.021). Except nickel (Ni) and cadmium (Cd), other metal concentrations were below the US EPA limits. Principal component analysis indicated a common source of the studied metals and two major factors (gas flaring and uncontrollable fossil fuel combustion) were identified; while non-carcinogenic risk due to inhalation indicated negligible health risk. Therefore, hazardous effects due to inhalation of trace metals in atmospheric particulate matter in the study area is minimal.

A Multi-Geochemical Characterization to Evaluate Anthropogenic Contamination in Marine Sediments from Port of Suape, Northeast of Brazil

To investigate the anthropogenic contamination of the Port of Suape, five surface sediments were collected and subjected to a geochemical characterization based on the determination of environmental biomarkers such as sterols, aliphatic and polycyclic aromatic hydrocarbons, and also metals and arsenic. Sterol analyses point to a moderate level of sewage contamination, while n-alkanes analyses indicated contamination by petroleum in an early stage of biodegradation. Polycyclic aromatic hydrocarbons analyses pointed to a mixture of contributions for the organic matter, which were predominantly found for petrogenic and pyrolytic sources. The quantification of trace metals indicated a low risk to the environment, except for As, which was identified as displaying moderate contamination. During the analysis of all biomarkers, the sediment collected near one of the shipyards was the most affected. These results enable comprehension of the level of contamination in an important Brazilian port and the need to develop remediation policies.

Effect of nanomaterials on the bioavailability of metals in sediments from a highly impacted tropical coastal environment

In this study, the impact of nanoparticles on the chemical behavior of metals in a tropical coastal environment was evaluated in a microcosm assay. The microcosms were assembled to reproduce the original environmental conditions, to evaluate the effects of two different nanoparticles. The aquariums were filled with water and sediment from Cunha River (Rio de Janeiro – Brazil) - which is highly contaminated by metals and organic compounds - and nanoparticles of hydroxyapatite (500 nm) and poly lactic-co-glycolic acid (PLGA) nanoparticles doped with Holmium-166 (200 nm), both radiolabeled with 99mTc. The quantification of trace metals (Cu, Zn, Mn, Fe, Cr and Pb) was performed in the water samples. The concentration data obtained for Fe, Cr and Pb were lower than ICP-OES Detection Limits (Fe: DL < 0.0343 mg.L−1, Cr: DL < 0.0036 mg.L−1 and Pb: DL < 0.0291 mg.L−1), while the results for Cu, Zn and Mn demonstrated that the presence of hydroxyapatite and PLGA nanoparticles had no influence on the behavior of dissolved metals, probably because of the high organic loads of the system, which may have overwhelmed or masked the interaction of nanomaterials with metals, once the natural organic matter could interact with the nanoparticles, favoring their aggregation and sedimentation and thus reducing their bioavailability and reactivity. Geochemical fractionation presented a relevant association of metals with the organic phase. In terms of environmental impact assessment of nanomaterials, it was concluded through 99mTc labelling that both nanomaterials (about 30% to 50%) remained in solution during the 49 h of the experiment.

Poluentes aquáticos estão associados a alterações reprodutivas e genotoxicidade em peixe estuarino (Sciades herzbergii - Bloch, 1794) da Costa Equatorial Amazônica

Estuaries are constantly subject to continuous environmental impacts of human activities, such as fisheries, port or industry, and domestic sewage, with fish being one of the most affected aquatic animals, reflecting the impacts directly on their bodies. Thus, the aim of this study was to carry out the biomonitoring of an estuary located on the Amazonian Equatorial Coast through analysis of PAHs (Polycyclic Aromatic Hydrocarbons) in the water, in addition to trace metals, histopathological alterations and analysis of erythrocyte micronuclei in Sciades herzbergii. S. herzbergii was used as a model species, due to its estuarine-resident behavior. Gonad and gill samples were subjected to histopathological evaluations. The quantification of trace metals was performed in samples of skeletal muscles of the animals collected, where concentrations of Lead (Pb), Copper (Cu), Zinc (Zn), Cadmium (Cd), Magnesium (Mg), Iron (Fe) and Aluminum (Al) were found. Except for Cadmium (Cd), all the concentrations were above the recommended limits. The PAHs analysis revealed the presence of Naphthalene and Acenaphthene in the water samples Histopathological and genotoxic analyses revealed of lesions in 100% of the study specimens. Thus, the histological and genotoxic alterations found in 100% of S. herzbergii specimens captured in São José Bay-MA are potentially associated with PAH concentrations present in the water. These results are potentially associated with the presence of PAH and trace metals, both in water and in animal tissues, inferring a general scenario of environmental contamination which directly implies a risk to the health and survival of the local biota. This study shows the relevance of continuous biomonitoring of estuarine ecosystems, in order to guide authorities regarding sewage management and ensure the evolutionary development of estuarine species, especially fishes of importance in the local cuisine, therefore related to human food security.

Trace elements (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in Mytilus galloprovincialis and Tapes decussatus from Faro and Ganzirri Lakes (Sicily, Italy): Flow cytometry applied for hemocytes analysis

BackgroundTrace elements present in sessile molluscs, are important because they are used in human consumption and it has significantly increased in recent years. While their filtering of the water can lead to their build-up of organic and inorganic materials that can be sampled and analyzed, this can also lead to bioaccumulation of harmful substances, such as essential and non-essential elements, that can harm the human health if in taken in high concentrations or for a long period of time. MethodsIn the present study, the trace metal content (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of two sessile crustaceans, 20 Mytilus galloprovincialis (mussel) and 20 Tapes decussatus (clam) in Faro and Ganzirri Lakes (Messina, Sicily, Italy) were analyzed. Haemolymph samples were taken on both molluscs in order to analyze the haemocyte population by flow cytometric analysis. Unpaired t-tests were used to determine significant differences for the essential and non-essential metallic elements concentrations in the lake waters and in the tissues of M. galloprovincialis and T. decussatus and for hemocyte populations R1 (halinocytes) and R2 (granulocytes). ResultsThe results suggested that that in Faro Lake, the tissue Al, Cr and Pb levels in M. galloprovincialis were higher than those for T. decussatus, in contrast to Mn, Fe, Ni, Cu, Zn and Cd, which were higher in T. decussatus. Unpaired t-tests showed that there were significantly higher proportions of halinocytes in M. galloprovincialis versus T. decussatus for both Faro Lake (41.8 % vs. 24.3 %; P < 0.001) and Ganzirri Lake (43.0 % vs. 22.4 %; P < 0.001). In contrast, while there were significantly higher proportions of granulocytes in Faro Lake (21.2 % vs. 9.1 %; P < 0.001), this difference was not seen for the granulocytes of M. galloprovincialis versus T. decussatus in Ganzirri Lake (9.6 % vs. 13.0 %). ConclusionThis study shows that M. galloprovincialis and T. decussatus can indeed bioaccumulate some of these metal, such that activation of the immune responses is specific to certain cell types. Future research must focus on the balance of trace elements in the consumption of these shellfish, and analyzes with more sophisticated tools can be used to diagnose the increased concentration of trace elements and the quantification of trace metals from shellfish to clams.

Quantification of major and trace elements in fluid inclusions and gas bubbles by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) with no internal standard: a new method

Abstract. Recent advances in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) open new perspectives for quantification of trace metals and metalloids in mineral-hosted fluid inclusions and glass-hosted gas bubbles. This work is devoted to a new method applied to quantify element concentrations (at parts-per-million and weight percent levels) in natural and synthetic fluid inclusions and gas bubbles by using only an external calibrator in cases where internal standardization is unavailable. For example, this method can be applied to calculate element (metal and metalloid) concentrations in carbonic (C–O–H) fluid inclusions and bubbles. The method is devoted to measuring incompatible (with the host mineral and glass) trace elements originally dissolved into the trapped fluid. The method requires precise estimation of the fluid density, the inclusion/bubble volume or average radius, and measurement of the laser ablation crater radius by independent microanalytical techniques as well as accurate data on the concentration of major/minor elements compatible with the host mineral (or host glass). This method, applicable for analyses of hydrous carbonic fluid inclusions and gas bubbles hosted in silicate minerals and glasses, relies on the absence of a matrix effect between fluid, host mineral and daughter phases (silicate, oxide or sulfide) and the external calibrator (e.g., reference silicate glasses) during the LA-ICP-MS analysis, an assumption validated by the use of femtosecond lasers.

Epigenetic responses in juvenile Lemon sharks (Negaprion brevirostris) during a coastal dredging episode in Bimini, Bahamas

Sharks serve as key predators in coastal areas, with several species using near shore habitats as nursery refuges. With many shark species threatened or endangered, it is now critical to increase the knowledge of how anthropogenic activities impact these populations. This study is the first attempt at characterizing epigenetic modifications in elasmobranchs, and their potential as biomarkers of stress and disease using a dredging event episode in the early 2000′s in Bimini, Bahamas, as a model system. Lemon shark fin samples were selected from a historic archive (1995–2012) of Bimini’s North (impacted) and South (control) shark nurseries, and classified as before (1995–2000), during (2001–2006), and after (2007–2012) the dredging event. Genome-wide DNA methylation was analyzed in these samples, along with the quantification of trace metals to investigate temporal and spatial patterns of metal concentrations. The obtained results revealed differential DNA methylation patterns in sharks from the North nursery (closest to the dredging site). While low concentrations of metals were found for all nursery sites and time frames, one trace metal (Manganese) was significantly correlated with the observed differences in DNA methylation. Overall, the findings of this study support DNA methylation as a potential stress biomarker for sharks, even in the absence of a reference genome. Furthermore, the identification of genomic regions differentially methylated in response to stress provides a basis for future analyses aimed at identifying gene networks and subsequent physiological responses to these events. Collectively, these analyses will help improve shark population monitoring, management, and conservation in impacted areas.

Single-cell visualization and quantification of trace metals in Chlamydomonas lysosome-related organelles

The acidocalcisome is an acidic organelle in the cytosol of eukaryotes, defined by its low pH and high calcium and polyphosphate content. It is visualized as an electron-dense object by transmission electron microscopy (TEM) or described with mass spectrometry (MS)-based imaging techniques or multimodal X-ray fluorescence microscopy (XFM) based on its unique elemental composition. Compared with MS-based imaging techniques, XFM offers the additional advantage of absolute quantification of trace metal content, since sectioning of the cell is not required and metabolic states can be preserved rapidly by either vitrification or chemical fixation. We employed XFM in Chlamydomonas reinhardtii to determine single-cell and organelle trace metal quotas within algal cells in situations of trace metal overaccumulation (Fe and Cu). We found up to 70% of the cellular Cu and 80% of Fe sequestered in acidocalcisomes in these conditions and identified two distinct populations of acidocalcisomes, defined by their unique trace elemental makeup. We utilized the vtc1 mutant, defective in polyphosphate synthesis and failing to accumulate Ca, to show that Fe sequestration is not dependent on either. Finally, quantitation of the Fe and Cu contents of individual cells and compartments via XFM, over a range of cellular metal quotas created by nutritional and genetic perturbations, indicated excellent correlation with bulk data from corresponding cell cultures, establishing a framework to distinguish the nutritional status of single cells.

A metrologically traceable protocol for the quantification of trace metals in different types of microplastic.

The presence of microplastic (MP) particles in aquatic environments raised concern about possible enrichment of organic and inorganic pollutants due to their specific surface and chemical properties. In particular the role of metals within this context is still poorly understood. Therefore, the aim of this work was to develop a fully validated acid digestion protocol for metal analysis in different polymers, which is a prerequisite to study such interactions. The proposed digestion protocol was validated using six different certified reference materials in the microplastic size range consisting of polyethylene, polypropylene, acrylonitrile butadiene styrene and polyvinyl chloride. As ICP-MS/MS enabled time-efficient, sensitive and robust analysis of 56 metals in one measurement, the method was suitable to provide mass fractions for a multitude of other elements beside the certified ones (As, Cd, Cr, Hg, Pb, Sb, Sn and Zn). Three different microwaves, different acid mixtures as well as different temperatures in combination with different hold times were tested for optimization purposes. With the exception of Cr in acrylonitrile butadiene styrene, recovery rates obtained using the optimized protocol for all six certified reference materials fell within a range from 95.9% ± 2.7% to 112% ± 7%. Subsequent optimization further enhanced both precision and recoveries ranging from 103% ± 5% to 107 ± 4% (U; k = 2 (n = 3)) for all certified metals (incl. Cr) in acrylonitrile butadiene styrene. The results clearly show the analytical challenges that come along with metal analysis in chemically resistant plastics. Addressing specific analysis tools for different sorption scenarios and processes as well as the underlying kinetics was beyond this study's scope. However, the future application of the two recommended thoroughly validated total acid digestion protocols as a first step in the direction of harmonization of metal analysis in/on MP will enhance the significance and comparability of the generated data. It will contribute to a better understanding of the role of MP as vector for trace metals in the environment.

Trace Metals in Groundwater of the South Eastern Piedmont Region of Mount Cameroon: Quantification and Health Risk Assessment

The South Eastern Piedmont Region of Mount Cameroon is getting in-creasingly populated. Groundwater is the main resource for drinking in this area; hence, the quantification of trace metals, suitability and quality of the groundwater resources for drinking, domestic and agro-industrial uses is of public and scientific concern. In this study, 10 samples were collected from 10 sites in September 2017. Field measurement of physicochemical parameters and investigation of the levels of trace metal content in groundwater was determined using Inductively Coupled Plasma Mass Spectroscopy ICP-MS. R-mode statistical analysis has been done and traces metals elements correlated with the physicochemical parameters and cluster analysis PCA carried out. The paper also highlights and determines the average daily dose ADD, the carcinogenic risks CR and the non-carcinogenic risk hazard quotient HQ which yields the hazard indices HI. The general trend of mean trace metal concentration in the sampled groundwater was in the order of: Zn > Fe > Al > V > Mn > Cu > Cr > Ni > Pb > As > Co > Cd > Sb. All the groundwater risk indices; ADD, CR, HQ and HI were less than 1 in categories of insignificant health risk. The severity of metal toxicity is governed by several factors, such as dose, nutrition, age, and even life style. Therefore, this low trend might not guarantee the complete absence of human health risk. Generally, from risk assessment on trace metals using risk indices, the analyzed water samples might not be at an alarming health risk. However, due to an increasing level of environmental pollution that might be imposed by increasing human activity in this region, water sources might become a potential sink of contaminants; this is significant reason that makes constant monitoring, implementation and treatment of groundwater for drinking purposes obligatory.

Sub-surface Biogeochemical Characteristics and Its Effect on Arsenic Cycling in the Holocene Gray Sand Aquifers of the Lower Bengal Basin

High arsenic (As) content in the fertile delta plains of West Bengal has been widely reported since the 1990s. The shallow grey sand aquifers (GSA) deposited during the Holocene, are more commonly used as potable water sources, but they have high As levels. The release of As into groundwater is influenced by indigenous microbial communities metabolizing different organic carbon sources present in the GSA sediments. After pre-screening the groundwater for assessing their microbial phylogenetic diversity, two50-m deep boreholes were drilled in the GSAs, and 19 sediment samples were recovered from each core. In each of these samples, grain-size distribution, sequential extraction, and quantification of trace metals and total extractable lipids were analyzed. The aquifer sediments consisted of medium to fine micaceous sand with clay lenses in between them; a thick clay layer occurred on top of both boreholes. Arsenic concentration in these sediments varied from 1.80 to 41.0 mg/kg and was mostly associated with the oxide and silicate-rich crystalline minerals. Arsenic showed a significant correlation with Fe in all fractions, suggesting the presence of Fe-(oxy)-hydroxides bound As minerals. The diagnostic lipid biomarkers showed presence of compounds derived from higher plants (epicuticular waxes) and microbial inputs. The biomarkers were abundant in clay and silt-rich layers. The samples indicated preferential preservation of n-alkanes over other functional compounds (e.g. alcohols and fatty acids), that are more reactive, and hence subject to further degradation. Sediments recovered from the borehole indicated the presence of Eustigmatophytes and vascular plant waxes that are mostly surface-derived. The sedimentary lipids also indicated the presence of complex petroleum-derived hydrocarbons. These compounds provide organic substrates, and support the preferential survival of specific microbial communities in these sediments.

Quantification of trace metals in infant formula premixes using laser-induced breakdown spectroscopy

Infant formula is a human milk substitute generally based upon fortified cow milk components. In order to mimic the composition of breast milk, trace elements such as copper, iron and zinc are usually added in a single operation using a premix. The correct addition of premixes must be verified to ensure that the target levels in infant formulae are achieved. In this study, a laser-induced breakdown spectroscopy (LIBS) system was assessed as a fast validation tool for trace element premixes. LIBS is a promising emission spectroscopic technique for elemental analysis, which offers real-time analyses, little to no sample preparation and ease of use. LIBS was employed for copper and iron determinations of premix samples ranging approximately from 0 to 120mg/kg Cu/1640mg/kg Fe. LIBS spectra are affected by several parameters, hindering subsequent quantitative analyses. This work aimed at testing three matrix-matched calibration approaches (simple-linear regression, multi-linear regression and partial least squares regression (PLS)) as means for precision and accuracy enhancement of LIBS quantitative analysis. All calibration models were first developed using a training set and then validated with an independent test set. PLS yielded the best results. For instance, the PLS model for copper provided a coefficient of determination (R2) of 0.995 and a root mean square error of prediction (RMSEP) of 14mg/kg. Furthermore, LIBS was employed to penetrate through the samples by repetitively measuring the same spot. Consequently, LIBS spectra can be obtained as a function of sample layers. This information was used to explore whether measuring deeper into the sample could reduce possible surface-contaminant effects and provide better quantifications.

Dispersion model and bioaccumulation factor validating trace metals in sea bream inhabiting wastewater drain outfalls

Our study was based on the recent increase in wastewater pollution and its deleterious effects to the marine ecosystem. Using numerical simulation (DESCAR-3.2 software program), we investigated the orientation and quantification of trace metals in wastewater discharges from permanent and semi-permanent drain outfalls constructed along the Kuwait Coastline encompassing six Kuwait Governorates (GI-GVI). This study was related to trace metals toxicity and bioaccumulation effects on the commercial yellow fin Sea bream, Acanthopagrus latus fish using probit program and bioaccumulation factor (BAF), respectively. Observations from wastewater discharges showed high trace metals concentrations in the sequence of Zn > Cr > Cu > Fe > Ni > Pb > Hg during winter compared to summer and in GI and GIV compared to drain outfalls in the other Governorates. Seasonally, trace metals in A. latus revealed the sequence of Zn > Fe > Cu > Ni > Cr > Pb > Hg in GI, GII and GIV indicating the significance of toxic metals that bioaccumulated from their surrounding untreated wastewater. Toxicity test revealed A. latus highly sensitive to Hg even at low lethal concentrations (LC15) compared to other metals. BAF in A. latus body parts was >1 indicating significant accumulation of trace metals from wastewater. However, BAF was <1 in Cr suggesting that A. latus could absorb trace metals from multiple sources over lengthy exposure period and not necessarily from wastewater containing rich Cr levels. Thus, the present findings validate A. latus as bioindicator to pollution more authentically by numerical simulation, toxicity and bioaccumulation tests compared to the traditional method of labeling A. latus as a pollution indicator.

Spatial distribution and human contamination quantification of trace metals and phosphorus in the sediments of Chaohu Lake, a eutrophic shallow lake, China

Distinguishing and quantifying anthropogenic trace metals and phosphorus accumulated in sediment is important for the protection of our aquatic ecosystems. Here, anthropogenic proportion and potential sources of trace metals and phosphorus in surface sediments of Chaohu Lake were evaluated based on the exhaustive geochemical data. The analysis shows that concentrations of major and trace metals, and phosphorus, displayed significant spatial diversity and almost all elements were over the pre-industrial background value, which should be related to the variations of sediment composition partially. Therefore, conservative element normalization was introduced and calculated enrichment factors (EFs) of the elements were referenced highlighting the human contamination. EFs of the major and trace metals, except Zn, Pb, and Cu, were all nearly 1.0, indicating the detrital origin. The EFs of Zn, Pb, Cu and phosphorus were 1.0-10.4, 1.0-3.8, 1.0-4.9, and 1.0-7.6, respectively, showing moderate to significant contamination. Higher EFs of Zn, Pb and Cu occurred in the mouth areas of Nanfei River and Zhegao River, and they decreased to the lake center in the northwest and northeast lake areas, respectively. We deduced that anthropogenic Zn, Pb, and Cu were mainly from urban and industrial point sources and the non-point sources of atmospheric deposition contributed little to their contamination. The EFs of phosphorus showed similar spatial degradation with that of Zn, Pb, and Cu. Moreover, higher EFs (>1) of phosphorus also occurred in other areas adjacent to the river mouths besides Nanfei River and Zhegao River. This indicated that the non-point agricultural source may also be responsible for the contamination of phosphorus in Chaohu Lake in addition to the urban sewage sources. Anthropogenic phosphorus was mainly concentrated in the speciation of NaOH-P, which had higher potential biological effects than the detrital proportion. Concentrations of Zn, Pb and Cu surpassed the threshold effect concentrations (TEC) of consensus-based sediment quality guidelines of freshwater ecosystems, especially in the contaminated northwest area of Chaohu Lake. This highlighted the contributions of anthropogenic contamination to the elevated potential biological effects of trace metals. Though there had been no obvious human contamination of Cr and Ni in Chaohu Lake, concentrations were all over the TECs, which may be due to higher background levels in the parent materials of soils and bedrocks in Chaohu Lake catchment.

Quantification of trace metals in sweeteners available in Portuguese market

Quantification of trace metals in sweeteners available in Portuguese market

Quantification of trace metals in water using complexation and filter concentration

Various metals undergo complexation with organic reagents, resulting in colored products. In practice, their molar absorptivities allow for quantification in the ppm range. However, a proper pre-concentration of the colored complex on paper filter lowers the quantification limit to the low ppb range. In this study, several pre-concentration techniques have been examined and compared: filtering the already complexed mixture, complexation on filter, and dipping of dye-covered filter in solution. The best quantification has been based on the ratio of filter reflectance at a certain wavelength to that at zero metal concentration. The studied complex formations (Ni ions with TAN and Cd ions with PAN) involve production of nanoparticle suspensions, which are associated with complicated kinetics. The kinetics of the complexation of Ni ions with TAN has been investigated and optimum timing could be found. Kinetic optimization in regard to some interferences has also been suggested.

Molecular dyes used for the detection of biological and environmental heavy metals: Highlights from 2004 to 2008

The coordination chemistry of heavy metals, for example, Fe3 + , Pb2 + , Cd2 + , Hg2 + , Cu2 + and Zn2 + , is of interest, in part because of their hazards and toxicity in biological, industrial and agricultural applications. Additionally, there is much interest in the detection and quantification of trace metals in the products of chemical synthesis, in particular sensors for detecting Pd2 + . There has been plethora of new molecular sensors for the detection of heavy metals, which utilise colorimetric or fluorescence mechanisms. This mini-review covers recent advances (2004–2008) in the development of molecular sensors that is restricted to molecular dyes. Other methods for the detection of heavy metals, for example, conjugated polymers and gold nanoparticles are omitted.

Comparison of Analytical Techniques for Analysis of Arsenic Adsorbed on Carbon

Abstract Activated carbon (AC) has been used extensively to treat arsenic-contaminated groundwater for a number of years. To date, attempts to quantify directly the amount of arsenic removed by the activated carbon using nondestructive methods has been limited. High-energy ion beam based proton induced x-ray emission (PIXE) is ideally suited to investigate the issues regarding the quantification of trace metals in solids. In this study, after the adsorption of arsenic on activated carbon, arsenic concentration in granular activated carbon (GAC) and powder activated carbon (PAC) were quantified using PIXE. The PIXE results were compared with atomic absorption spectrometry (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. Some differences are observed between these measurements. The differences are greater in the case of GAC compared to PAC. These differences are mainly due to the inhomogeneous structure of GAC and PAC, which includes the variable surface properties such as surface area and pore sizes in each granule or particle. The larger differences are mainly due to the increased particle dimensions of GAC compared to PAC and the nature of the internal pore structure of GAC, which results in different amounts of arsenic adsorbed on different granules of GAC or even in different regions of one granule. This inhomogeneity of arsenic concentration is clearly visible in the arsenic concentration map generated for a single GAC particle using microbeam PIXE.

Imaging and quantification of trace metals in thin biological specimens using microprobe techniques: Synchrotron induced X-ray fluorescence microprobe and nuclear microprobe

The combination of Synchrotron X-Ray Fluorescence microprobe (SXRF) with other micro-analytical techniques based on accelerated particle beams, such as Rutherford Backscattering Spectrometry (RBS), and Particle Induced X-ray Emission (PIXE) enable to quantify SXRF results of thin biological specimens. The same specimens were analysed by both techniques. The average thickness calculated by RBS of discrete tissue regions in equivalent sample sections was used to normalise SXRF data. Analysing the same sample region with PIXE technique, simultaneously to RBS, can validate the methodology once it will enable to compare concentrations obtained for elements that are detected by both SXRF and PIXE. Major departures were found for the quantification of Ca and Ti. For Cr and Fe a good agreement was found between both micro-analytical techniques. Differences below 20% were obtained for the majority of the elements and samples analysed. The procedure can be applied to produce quantitative elemental maps and it will be advantageous to quantify toxic elements present at low concentrations in tissues, such as Cr, Ni and Pb, which can only be efficiently assessed by SXRF.