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1.
Food Chem ; 426: 136487, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37307739

RESUMO

The geographical authentication in the agrifood industry has become a major issue to guarantee the quality of food products. Olive oil (OO) is particularly a complex matrix and establishing a reliable approach for linking OO samples to their origin is an analytical challenge. In this study, the isotopic composition of carbon, strontium and the concentrations of seventeen elements were determined in OOs from Tunisia, Southern France and the South Basque country. The preliminary results overlapped and showed that, taken individually, the isotopic and elemental approaches were not discriminant. A linear discriminant analysis applied to δ13C, 87Sr/86Sr and to the concentrations of 4 selected trace elements (Fe, Mn, V and Cr) allowed to classify, with high resolution, olive oils into 3 groups according to their provenance. The combination of the plant growing environment, the geological background, the mineral composition of the soil and the production process lead to a novel approach to deal with fraudulent practices in OO sector.


Assuntos
Oligoelementos , Azeite de Oliva , Isótopos de Carbono/análise , Oligoelementos/análise , Estrôncio/análise , França , Isótopos de Estrôncio/análise , Isótopos/análise
2.
Molecules ; 27(6)2022 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-35335378

RESUMO

The olive oil industry is subject to significant fraudulent practices that can lead to serious economic implications and even affect consumer health. Therefore, many analytical strategies have been developed for olive oil's geographic authentication, including multi-elemental and isotopic analyses. In the first part of this review, the range of multi-elemental concentrations recorded in olive oil from the main olive oil-producing countries is discussed. The compiled data from the literature indicates that the concentrations of elements are in comparable ranges overall. They can be classified into three categories, with (1) Rb and Pb well below 1 µg kg-1; (2) elements such as As, B, Mn, Ni, and Sr ranging on average between 10 and 100 µg kg-1; and (3) elements including Cr, Fe, and Ca ranging between 100 to 10,000 µg kg-1. Various sample preparations, detection techniques, and statistical data treatments were reviewed and discussed. Results obtained through the selected analytical approaches have demonstrated a strong correlation between the multi-elemental composition of the oil and that of the soil in which the plant grew. The review next focused on the limits of olive oil authentication using the multi-elemental composition method. Finally, different methods based on isotopic signatures were compiled and critically assessed. Stable isotopes of light elements have provided acceptable segregation of oils from different origins for years already. More recently, the determination of stable isotopes of strontium has proven to be a reliable tool in determining the geographical origin of food products. The ratio 87Sr/86Sr is stable over time and directly related to soil geology; it merits further study and is likely to become part of the standard tool kit for olive oil origin determination, along with a combination of different isotopic approaches and multi-elemental composition.


Assuntos
Isótopos , Solo , Geografia , Azeite de Oliva , Estrôncio
3.
Talanta ; 234: 122433, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364413

RESUMO

Wine is one of the most counterfeit product and therefore, requires certifying of its origin and provenance. For authentication purposes, analytical strategies for the determination of Sr and Pb isotopic ratios were adapted for Champagne and sparkling wines. All analytical steps have been carefully adapted and optimized regarding sample preparation, mineralization, and purification by resins as well as isotopic composition measurements on 3 different MC ICP-MS instruments. Further, a global approach using an "in-house" reference material of Champagne (ChRM) was realized and used throughout as well as routine analytical conditions to guaranty samples isotopic quality determination over 3 years. These developments allowed to select the best conditions at all steps for reaching the best precision and accuracy to be used under routine conditions for samples origin discrimination. The best condition of mineralization was obtained with a hot block system allowing both efficiency in digestion and high sample throughput. Detailed conditions of purification for both Sr and Pb isotopes were also optimized and discussed. These different optimization steps on the whole analytical chain allowed to estimate a global precision suitable to be used routinely to discriminate the origin of different Champagne samples. For Sr isotopic analysis (87Sr/86Sr), the overall external precision based on preparation replicates of ChRM was 2σ = 0.000024 (n = 36) and for the Pb isotopes analysis (208Pb/206Pb), the precision obtained on ChRM was 2σ = 0.0024 (n = 15). Finally, we have applied these developments by combining both Sr and Pb isotopic ratios in order to discriminate the origin of sparkling wines from around the world. The combined isotopic signature, using both Sr and Pb isotopes ratios, permitted a clear discrimination between certified Champagne wines and other European and Non-European sparkling wines.


Assuntos
Vinho , Isótopos/análise , Chumbo , Análise Espectral , Vinho/análise
4.
Chemosphere ; 279: 130631, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134422

RESUMO

The Hg isotopic composition of 1-year-old Norway spruce (Picea abies) shoots collected from Saarland cornurbation Warndt, Germany, since 1985 by the German Environmental Specimen Bank, were measured for a better understanding of the temporal trends of Hg sources. The isotopic data showed that Hg was mainly taken up as gaseous element mercury (GEM) and underwent oxidation in the spruce needles; this led to a significant decrease in the δ202Hg compared with the atmospheric Hg isotopic composition observed for deciduous leaves and epiphytic lichens. Observation of the odd mass-independent isotopic fractionation (MIF) indicated that Δ199Hg and Δ201Hg were close to but slightly lower than the actual values recorded from the atmospheric measurement of the GEM isotopic composition in non-contaminated sites in U.S. and Europe, whereas observation of the even-MIF indicated almost no differences for Δ200Hg. This confirmed that GEM is a major source of Hg accumulation in spruce shoots. Interestingly, the Hg isotopic composition in the spruce shoots did not change very significantly during the study period of >30 years, even as the Hg concentration decreased significantly. Even-MIF (Δ200Hg) and mass-dependent fractionation (MDF) (δ202Hg) of the Hg isotopes exhibited slight decrease with time, whereas odd-MIF did not show any clear trend. These results suggest a close link between the long-term evolution of GEM isotopic composition in the air and the isotopic composition of bioaccumulated Hg altered by mass-dependent fraction in the spruce shoots.


Assuntos
Mercúrio , Picea , Monitoramento Ambiental , Europa (Continente) , Alemanha , Mercúrio/análise , Isótopos de Mercúrio/análise , Noruega
5.
Anal Bioanal Chem ; 412(19): 4483-4493, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32424796

RESUMO

An interlaboratory study on the National Institute for Environmental Studies (NIES) certified reference material (CRM) No. 28 Urban Aerosols, collected on the filters of a central ventilating system in a building in Beijing city center, was performed to obtain informative values of Hg isotopic composition and total Hg (THg) mass fraction. The THg mass fraction was determined by four organizations using atomic absorption spectrometry; it resulted in the mean value of 1.19 ± 0.12 mg/kg (2SD, n = 24). The Hg isotopic composition of the CRM was measured and intercompared at two different institutions by cold vapor generation system coupled to multicollector inductively coupled plasma mass spectrometry. Subsequently, a conventional dissolution method that uses a mixture of HNO3/HCl/H2O2 in Hotblock® and two different dissolution methods that use a mixture of HNO3/HCl with a microwave and a digestion bomb were applied. The Hg isotopic compositions were δ202Hg = - 1.26 ± 0.17‰, Δ199Hg = - 0.23 ± 0.06‰, Δ200Hg = 0.01 ± 0.07‰, and Δ201Hg = - 0.22 ± 0.09‰ (2SD, n = 18) for the conventional method, which agree well with those obtained using microwave and bomb digestion. Our results indicate that, for the quality control of particulate matter analyses, this CRM is appropriate for use in environmental and geochemical studies. Graphical abstract.

6.
Food Chem ; 303: 125277, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473460

RESUMO

Lead concentrations and lead isotope ratios of 43 authentic Bordeaux wines from prestigious châteaux and 14 suspicious Bordeaux origin were determined to evaluate their potential for authenticity and geographical origin assessment. Results have shown that the total Pb concentrations in Bordeaux wines drastically decreased over the previous 50 years with a clear shift of isotopic signatures towards geogenic values corresponding to an overall trend of European environmental lead monitoring. The Pb isotopic ratios determined in both series of samples clearly demonstrated that suspicious Bordeaux wines displayed Pb isotopic signatures statistically distinctive from those obtained for authentic wines. This observation was confirmed by the three-isotope mixing lines obtained between the geogenic and the anthropogenic Pb isotopes data that characterize European and Asian sources. The use these specific three-isotope plots allows a non-ambiguous discrimination between authentic Pauillac AOC and the counterfeited ones.


Assuntos
Qualidade dos Alimentos , Geografia , Chumbo/análise , Chumbo/química , Vinho/análise , Fraude , Isótopos
7.
Food Chem ; 294: 35-45, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126474

RESUMO

The 87Sr/86Sr ratio and Sr concentrations of 43 authentic Bordeaux wines from the world's most prestigious châteaux are presented in the context of their relation to the geographical origin of wine and authenticity. The results demonstrate relatively narrow spans of variabilities observed for 87Sr/86Sr ratio and Sr concentrations in authentic Bordeaux wines, which can be used with reasonable certainty as specific parameters for identifying regional wineries. For comparison, a set of imitated Bordeaux wines was studied for Sr isotopic and elemental compositions. A significant excess of both parameters in suspicious wines were found in reference to authentic values. Such natural and anthropogenically induced variations offer an enhanced discriminating potential of Sr. The unique Sr binary signature may detect imitated wines and trace genuine products from different regional wineries. The obtained results shown a promising perspective for wine authenticity control by means of Sr isotopic and elemental composition.


Assuntos
Estrôncio/análise , Vinho/análise , Fazendas , Espectrometria de Massas , Solo/química , Isótopos de Estrôncio/análise
8.
Environ Pollut ; 243(Pt B): 961-971, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30248603

RESUMO

Multi-elemental isotopic approach associated with a land-use characteristic sampling strategy may be relevant for conducting biomonitoring studies to determine the spatial extent of atmospheric contamination sources. In this work, we investigated how the combined isotopic signatures in epiphytic lichens of two major metallic pollutants, lead (206Pb/207Pb) and mercury (δ202Hg, Δ199Hg), together with the isotopic composition of nitrogen and carbon (δ15N, δ13C), can be used to better constrain atmospheric contamination inputs. To this end, an intensive and integrated sampling strategy based on land-use characteristics (Geographic information system, GIS) over a meso-scale area (Pyrénées-Atlantiques, SW France) was applied to more than 90 sampling stations. To depict potential relationships between such multi-elemental isotopic fingerprint and land-use characteristics, multivariate analysis was carried out. Combined Pb and Hg isotopic signatures resolved spatially the contribution of background atmospheric inputs from long range transport, from local legacy contamination (i.e. Pb) or actual industrial inputs (i.e. Pb and Hg from steel industry). Application of clustering multivariate analysis to all studied isotopes provided a new assessment of the region in accordance with the land-use characteristics and anthropogenic pressures.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Chumbo/análise , Líquens/química , Mercúrio/análise , Carbono/análise , Poluição Ambiental , França , Sistemas de Informação Geográfica , Isótopos , Nitrogênio/análise , Aço
9.
Front Chem ; 6: 49, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29872651

RESUMO

Food integrity is a general term for sound, nutritive, healthy, tasty, safe, authentic, traceable, as well as ethically, safely, environment-friendly, and sustainably produced foods. In order to verify these properties, analytical methods with a higher degree of accuracy, sensitivity, standardization and harmonization and a harmonized system for their application in analytical laboratories are required. In this view, metrology offers the opportunity to achieve these goals. In this perspective article the current global challenges in food analysis and the principles of metrology to fill these gaps are presented. Therefore, the pan-European project METROFOOD-RI within the framework of the European Strategy Forum on Research Infrastructures (ESFRI) was developed to establish a strategy to allow reliable and comparable analytical measurements in foods along the whole process line starting from primary producers until consumers and to make all data findable, accessible, interoperable, and re-usable according to the FAIR data principles. The initiative currently consists of 48 partners from 18 European Countries and concluded its "Early Phase" as research infrastructure by organizing its future structure and presenting a proof of concept by preparing, distributing and comprehensively analyzing three candidate Reference Materials (rice grain, rice flour, and oyster tissue) and establishing a system how to compile, process, and store the generated data and how to exchange, compare them and make them accessible in data bases.

10.
Food Chem ; 246: 313-322, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29291854

RESUMO

We have examined the potential of discriminant inorganic constituents (trace-, ultra-trace elements and Sr isotope ratios) to assess the origin of world famous brands of European dry-cured hams. The variation of the multielemental composition with principal component analysis allowed to discriminate the origin of Bayonne hams. Determined ratio 87Sr/86Sr was recognized as a strong additional distinctive parameter. The ratio 87Sr/86Sr allowed to better separate all the different categories of hams in addition to the multi-elemental detection. The major contribution of the value 87Sr/86Sr for the Bayonne ham is directly related to its curing due to the salt used in process coming from the nearby salt mine Salies-de-Béarn. Since the salt represents around 4% of the final product, it will therefore strongly influence the elemental and isotopic composition of hams. The overall discrimination potential of strontium isotope ratio is evidenced in the final statistical discrimination of the origin of hams.


Assuntos
Carne/classificação , Isótopos de Estrôncio/análise , Animais , Carne/análise , Cloreto de Sódio , Cloreto de Sódio na Dieta/análise , Suínos , Oligoelementos/análise
11.
Anal Bioanal Chem ; 408(11): 2641-8, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26753975

RESUMO

Mercury (Hg) pollution is considered a major environmental problem due to the extreme toxicity of Hg. However, Hg metabolic pathways in biota remain elusive. An understanding of these pathways is crucial to elucidating the (eco)toxic effects of Hg and its biogeochemical cycle. The development of a new analytical methodology based on both speciation and natural isotopic fractionation represents a promising approach for metabolic studies of Hg and other metal(loid)s. Speciation provides valuable information about the reactivity and potential toxicity of metabolites, while the use of natural isotopic signature analysis adds a complementary dynamic dimension that allows the life history of the target element to be probed, the source of the target element (i.e., the source of pollution) to be identified, and reactions to be tracked. The resulting combined (bio)molecular and isotopic signature affords precious insight into the behavior of Hg in biota and Hg detoxification mechanisms. In the long term, this highly innovative methodology could be used in life and environmental science studies of metal(loid)s to push back the frontiers of our knowledge in this field. This paper summarizes the current status of the application of Hg speciation and the isotopic signature of Hg at the biomolecular level in living organisms, and discusses potential future uses of this combination of techniques.


Assuntos
Isótopos de Mercúrio/química , Mercúrio/classificação , Espectrometria de Massas , Mercúrio/química
12.
Environ Sci Pollut Res Int ; 22(11): 8536-48, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25561253

RESUMO

Geographically based investigations into atmospheric bio-monitoring usually provide information on concentration or occurrence data and spatial trends of specific contaminants over a specified study area. In this work, an original approach based on geographic information system (GIS) was used to establish metal contents (Hg, Cu, Pb, and Cd) in epiphytic lichens from 90 locations as atmospheric bio-monitors over a meso-scale area (Pyrénées-Atlantiques, southwestern France). This approach allows the integration of the heterogeneity of the territory and optimization of the sampling sites based on both socioeconomical and geophysical parameters (hereafter defined as urban, industrial, agricultural, and forested areas). The sampling strategy was first evaluated in several sites (n = 15) over different seasons and years in order to follow the temporal variability of the atmospheric metal input in lichens. The results demonstrate that concentration ranges remain constant over different sampling periods in "rural" areas (agricultural and forested). Higher variability is observed in the "anthropized" urban and industrial areas in relation to local atmospheric inputs. In this context, metal concentrations in lichens over the whole study show that (1) Hg and Cd are homogeneous over the whole territory (0.14 ± 0.04 and 0.38 ± 0.26 mg/kg, respectively), whereas (2) Cu and Pb are more concentrated in "anthropized" areas (9.3 and 11.9 mg/kg, respectively) than in "rural" ones (6.8 and 6.0 mg/kg, respectively) (Kruskall-Wallis, K(Cu) = 13.7 and K(Pb) = 9.7, p < 0.00001). They also showed a significant local enrichment for all metals in many locations in the Pays Basque (West) mainly due to metal and steel industrial activities. This confirms the local contribution of this contamination source over a wider geographic scale. A multiple linear regression model was applied to give an integrated spatialization of the data. This showed significant relationships for Pb and Cu (adjusted r (2) of 0.39 and 0.45, respectively), especially with regards to variables such as industry and road densities (source factors) and elevation or water balance (remote factors). These results show that an integrated GIS-based sampling strategy can improve biomonitoring data distribution and allows better differentiation of local and long-range contamination.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental/métodos , Líquens/metabolismo , Metais Pesados/análise , Poluentes Atmosféricos/farmacocinética , Monitoramento Ambiental/estatística & dados numéricos , França , Sistemas de Informação Geográfica , Modelos Lineares , Espectrometria de Massas , Metais Pesados/farmacocinética , Fatores Socioeconômicos , Espectrofotometria Atômica , Estatísticas não Paramétricas
13.
Environ Monit Assess ; 186(12): 8141-50, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25117495

RESUMO

Mercury (Hg) is considered a global pollutant, and the scientific community has shown great concern about its toxicity as it may affect the biota of entire systems, through bioaccumulation and bioamplification processes of its organic form, methylmercury (MeHg), along food web. However, few research studies deal with bioaccumulation of Hg from marine primary producers and the first-order consumers. So, this study aims to determine Hg distribution and concentration levels in phytoplankton and zooplankton in the Cabo Frio Bay, Brazil, a site influenced by coastal upwelling. The results from Hg speciation analyses show that inorganic mercury Hg(II) was the predominant specie in plankton from this bay. The annual Hg species distribution in plankton shown mean concentration of 2.00 ± 1.28 ng Hg(II) g(-1) and 0.15 ± 0.08 ng MeHg g(-1) wet weight (phytoplankton) and 2.5 ± 2.03 ng Hg(II) g(-1) and 0.25 ± 0.09 ng MeHg g(-1) wet weight (zooplankton). Therefore, upwelling zones should be considered in the Hg biogeochemical cycle models as a process that enhances Hg(II) bioaccumulation in plankton, raising its bioavailability and shelf deposition.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Baías/química , Brasil , Monitoramento Ambiental , Cadeia Alimentar , Mercúrio/metabolismo , Compostos de Metilmercúrio/análise , Compostos de Metilmercúrio/metabolismo , Plâncton/metabolismo , Poluentes Químicos da Água/metabolismo , Zooplâncton/metabolismo
14.
Environ Sci Process Impacts ; 16(1): 10-27, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24166047

RESUMO

Environmental specimen banks (ESBs) have been a fundamental tool for many nations to monitor contaminant temporal and spatial trends, study fate and transport, and assess the severity and risks of pollution. The specimens archived in ESBs are among the longest time-series, most geographically robust, and highest integrity samples available for performing environmental research. Mercury (Hg) remains one of the world's most ubiquitous environmental contaminants, and ESBs have played a prominent role in Hg research. Historically this has involved measuring concentrations of Hg species in various environmental matrices, but the emerging field of Hg stable isotope research provides a new analytical approach that can augment these traditional techniques. Signatures of Hg isotope fractionation have been effectively used for source apportionment and for elucidating Hg biogeochemical cycling. As the research surrounding Hg stable isotopes continues to mature, ESBs can play a useful role in analytical quality control, provide a robust and economical sample archive to expand and diversify the inventory of Hg isotope measurements, and be used to develop and test hypotheses to evaluate whether broadly prevailing paradigms are supported. Samples archived in ESBs are available for request by external collaborators in order to perform high impact research, and should be utilized more effectively to address emerging global environmental concerns.


Assuntos
Bancos de Espécimes Biológicos , Monitoramento Ambiental/métodos , Isótopos de Mercúrio/análise , Mercúrio/análise , Poluentes Químicos da Água/análise , Ecossistema
15.
Anal Chem ; 84(18): 7874-80, 2012 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-22845833

RESUMO

A new method to determine Pb isotope ratio without ion-exchange-matrix separation is proposed. After acid digestion, Pb was ethylated to Et(4)Pb, separated from the digested solution (black shale, asphaltene, crude oil and kerogen) by extraction in isooctane, and then injected into a gas chromatograph coupled to a multicollector inductively coupled plasma mass spectrometer. Seven isotopes ((202)Hg, (203)Tl, (204)Pb, (205)Tl, (206)Pb, (207)Pb, (208)Pb) were monitored simultaneously with peak duration of 23 s. GC elution was operated under wet plasma conditions where a thallium standard solution was introduced to the mass spectrometer for mass bias correction. The total time of the procedure (sample preparation and analysis, after acid digestion) was reduced by a factor of 15 compared to conventional-continuous sample introduction. Data treatment was carried out using the linear regression slope method. Mass bias was corrected using the double correction method (first thallium normalization followed by classical bracketing). For the (208/206)Pb and (207/206)Pb ratios, precision (2RSD(EXT), n = 21) was 49 and 69 ppm, and the bias between experimental results and reference values was better than 0.0033 and 0.0007 ‰, when injecting 1.2 ng of ethylated Pb SRM NIST 981 solution. Results obtained by this method were validated by comparison with those obtained via conventional-continuous sample introduction. The applicability of this approach was demonstrated with the analysis of black shale, asphaltene, crude oil and kerogen samples.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Chumbo/análise , Petróleo/análise , Hidrocarbonetos/química , Isótopos/análise , Mercúrio/química , Octanos/química , Tálio/química
16.
Environ Sci Technol ; 46(11): 5902-11, 2012 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-22545798

RESUMO

Mercury undergoes several transformations that influence its stable isotope composition during a number of environmental and biological processes. Measurements of Hg isotopic mass-dependent (MDF) and mass-independent fractionation (MIF) in food webs may therefore help to identify major sources and processes leading to significant bioaccumulation of methylmercury (MeHg). In this work, δ(13)C, δ(15)N, concentration of Hg species (MeHg, inorganic Hg), and stable isotopic composition of Hg were determined at different trophic levels of the remote and pristine Lake Baikal ecosystem. Muscle of seals and different fish as well as amphipods, zooplankton, and phytoplankton were specifically investigated. MDF during trophic transfer of MeHg leading to enrichment of heavier isotopes in the predators was clearly established by δ(202)Hg measurements in the pelagic prey-predator system (carnivorous sculpins and top-predator seals). Despite the low concentrations of Hg in the ecosystem, the pelagic food web reveals very high MIF Δ(199)Hg (3.15-6.65‰) in comparison to coastal fish (0.26-1.65‰) and most previous studies in aquatic organisms. Trophic transfer does not influence MIF signature since similar Δ(199)Hg was observed in sculpins (4.59 ± 0.55‰) and seal muscles (4.62 ± 0.60‰). The MIF is suggested to be mainly controlled by specific physical and biogeochemical characteristics of the water column. The higher level of MIF in pelagic fish of Lake Baikal is mainly due to the bioaccumulation of residual MeHg that is efficiently turned over and photodemethylated in deep oligotrophic and stationary (i.e., long residence time) freshwater columns.


Assuntos
Fracionamento Químico/métodos , Cadeia Alimentar , Lagos/química , Compostos de Metilmercúrio/metabolismo , Animais , Caniformia/metabolismo , Isótopos de Carbono , Monitoramento Ambiental , Peixes/metabolismo , Geografia , Luz , Mercúrio/metabolismo , Isótopos de Mercúrio , Metilação/efeitos da radiação , Peso Molecular , Músculos/metabolismo , Isótopos de Nitrogênio , Federação Russa , Água do Mar/química , Poluentes Químicos da Água/metabolismo
17.
Environ Pollut ; 166: 226-32, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22522226

RESUMO

Mercury concentration ([Hg]), δ(15)N, and δ(13)C values were measured in eggs from common murres (Uria aalge), thick-billed murres (U. lomvia), glaucous gulls (Larus hyperboreus), and glaucous-winged gulls (L. glaucescens) collected in Alaska from 1999 to 2005. [Hg] was normalized to a common trophic level using egg δ(15)N values and published Hg trophic magnification factors. Egg [Hg] was higher in murres from Gulf of Alaska, Cook Inlet, and Norton Sound regions compared to Bering Sea and Bering Strait regions, independent of trophic level. We believe the Yukon River outflow and terrestrial Hg sources on the southern Seward Peninsula are responsible for the elevated [Hg] in Norton Sound eggs. Normalizing for trophic level generally diminished or eliminated differences in [Hg] among taxa, but temporal variability was unrelated to trophic level. Normalizing murre egg [Hg] by trophic level improves the confidence in regional comparisons of Hg sources and biogeochemical cycling in Alaska.


Assuntos
Aves , Monitoramento Ambiental , Poluentes Ambientais/análise , Mercúrio/análise , Óvulo/química , Alaska , Animais , Fenômenos Ecológicos e Ambientais , Poluição Ambiental/estatística & dados numéricos , Cadeia Alimentar
18.
Environ Sci Technol ; 46(10): 5327-35, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-22519440

RESUMO

Elevated mercury concentrations ([Hg]) were found in Alaskan murre (Uria spp.) eggs from the coastal embayment of Norton Sound relative to insular colonies in the northern Bering Sea-Bering Strait region. Stable isotopes of Hg, carbon, and nitrogen were measured in the eggs to investigate the source of this enrichment. Lower δ(13)C values in Norton Sound eggs (-23.3‰ to -20.0‰) relative to eggs from more oceanic colonies (-20.9‰ to -18.7‰) indicated that a significant terrestrial carbon source was associated with the elevated [Hg] in Norton Sound, implicating the Yukon River and smaller Seward Peninsula watersheds as the likely Hg source. The increasing [Hg] gradient extending inshore was accompanied by strong decreasing gradients of δ(202)Hg and Δ(199)Hg in eggs, indicating lower degrees of mass-dependent (MDF) and mass-independent Hg fractionation (MIF) (respectively) in the Norton Sound food web. Negative or zero MDF and MIF signatures are typical of geological Hg sources, which suggests murres in Norton Sound integrated Hg from a more recent geological origin that has experienced a relatively limited extent of aquatic fractionation relative to more oceanic colonies. The association of low δ(202)Hg and Δ(199)Hg with elevated [Hg] and terrestrial δ(13)C values suggested that Hg stable isotopes in murre eggs effectively differentiated terrestrial/geogenic Hg sources from oceanic reservoirs.


Assuntos
Charadriiformes/metabolismo , Monitoramento Ambiental , Mercúrio/análise , Óvulo/metabolismo , Poluentes Químicos da Água/análise , Animais , Fracionamento Químico , Ecossistema , Marcação por Isótopo , Isótopos de Mercúrio , Oceanos e Mares
19.
Talanta ; 89: 12-20, 2012 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-22284453

RESUMO

Mercury is a toxic compound that can contaminate humans through food and especially via fish consumption. Mercury's toxicity depends on the species, with methylmercury being the most hazardous form for humans. Hg speciation analysis has been and remains a widely studied subject because of the potential difficulty of preserving the initial distribution of mercury species in the analysed sample. Accordingly, many analytical methods have been developed and most of them incur significant loss and/or cross-species transformations during sample preparation. Therefore, to monitor and correct artefact formations, quantification by isotope dilution is increasingly used and provides significant added value for analytical quality assurance and quality control. This review presents and discusses the two different modes of application of isotope dilution analysis for elemental speciation (i.e. species-unspecific isotope dilution analysis and species-specific isotope dilution analysis) and the different quantification techniques (i.e. classical and multiple spike isotope dilution analyses). Isotope tracers are thus used at different stages of sample preparation to determine the extent of inter-species transformations and correct such analytical artefacts. Finally, a synthesis of the principal methods used for mercury speciation in seafood using isotope dilution analysis is presented.


Assuntos
Peixes/metabolismo , Contaminação de Alimentos/análise , Mercúrio/análise , Compostos de Metilmercúrio/análise , Alimentos Marinhos/análise , Animais , Liofilização , Humanos , Espectrometria de Massas , Radioisótopos de Mercúrio/química , Controle de Qualidade , Técnica de Diluição de Radioisótopos , Sensibilidade e Especificidade
20.
Mass Spectrom Rev ; 31(4): 504-21, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22161869

RESUMO

This work reviews the basis and all the existing publications on the hyphenation of chromatography-based techniques to MC-ICPMS for isotopic studies that were published until the end of 2010. A brief historical retrospective of the measurement of isotope ratios from transient signals by ICPMS with different sample introduction techniques is also included. The most important experimental parameters and data reduction strategies affecting the accurate and precise measurement of compound-specific isotope ratios by either HPLC or GC coupled to MC-ICPMS are discussed. All the applications are reported and critically reviewed in terms of analytical characteristics, performances, optimization, advantages and disadvantages and future applicability to the environmental, geochemical, or bioinorganic studies.

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