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1.
Environ Sci Technol ; 55(8): 4813-4821, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33755433

RESUMO

Vanadium, a potentially toxic metal, is enriched in the environment from anthropogenic releases, particularly during fossil fuel production and use and steel manufacturing. Metal stable isotopes are sophisticated tools to trace pollution; however, only recent analytical advances have allowed for the accurate and precise measurement of vanadium isotope ratios (δ51V). To examine its potential as a tracer in terrestrial and aquatic ecosystems, δ51V was measured in soil, plant, lichen, marten, and lake sediment from sites near vanadium emissions at oil sands mines (Alberta, Canada) and in the sediment and biota (algae, zooplankton, fish) from a remote subarctic lake (Northwest Territories, Canada). Samples from Alberta had distinct δ51V values with marten liver the lowest (-1.7 ± 0.3‰), followed by lichen (-0.9 ± 0.1‰), soil (-0.7 ± 0.1‰), sediment (-0.5 ± 0.2‰), and plant root (-0.3 ± 0.2‰). Average values were lower than Alberta bitumen and petroleum coke (-0.1 ± 0.1‰). Plant roots had systematically higher δ51V than the soil from which they grew (Δ51Vplant-soil = 0.4 ± 0.1‰), while δ51V of lichen and aquatic biota were lower (0.1-0.3‰) than likely crustal sources. These δ51V measurements in terrestrial and aquatic biota demonstrate promise for tracer applications, although further study of its biological fractionation is needed.


Assuntos
Cadeia Alimentar , Poluentes Químicos da Água , Alberta , Animais , Biota , Isótopos de Carbono , Ecossistema , Monitoramento Ambiental , Isótopos/análise , Territórios do Noroeste , Campos de Petróleo e Gás , Vanádio , Poluentes Químicos da Água/análise
2.
Ecotoxicol Environ Saf ; 215: 112122, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33725489

RESUMO

The human ingestion of mercury (Hg) from sea food is of big concern worldwide due to adverse health effects, and more specifically if shark consumption constitutes a regular part of the human diet. In this study, the total mercury (THg) concentration in muscle tissue were determined in six sympatric shark species found in a fishing vessel seized in the Galapagos Marine Reserve in 2017. The THg concentrations in shark muscle samples (n = 73) varied from 0.73 mg kg-1 in bigeye thresher sharks (Alopias superciliosus) to 8.29 mg kg-1 in silky sharks (Carcharhinus falciformis). A typical pattern of Hg bioaccumulation was observed for all shark species, with significant correlation between THg concentration and shark size for bigeye thresher sharks, pelagic thresher sharks (Alopias pelagicus) and silky sharks. Regarding human health concerns, the THg mean concentration exceeded the maximum weekly intake fish serving in all the studied species. Mass-Dependent Fractionation (MDF, δ202Hg values) and Mass-Independent Fractionation (MIF, Δ199Hg values) of Hg in whitetip sharks (Carcharhinus longimanus) and silky sharks, ranged from 0.70‰ to 1.08‰, and from 1.97‰ to 2.89‰, respectively. These high values suggest that both species are feeding in the epipelagic zone (i.e. upper 200 m of the water column). While, blue sharks (Prionace glauca), scalloped hammerhead sharks (Shyrna lewini) and thresher sharks were characterized by lower Δ199Hg and δ202Hg values, indicating that these species may focus their foraging behavior on prey of mesopelagic zone (i.e. between 200 and 1000 m depth). In conclusion, the determination of THg concentration provides straight-forward evidence of the human health risks associated with shark consumption, while mercury isotopic compositions constitute a powerful tool to trace the foraging strategies of these marine predators. CAPSULE: A double approach combining Hg concentrations with stable isotopes ratios allowed to assess ontogeny in common shark species in the area of the Galapagos Marine Reserve and the human health risks concern associated to their consumption.


Assuntos
Mercúrio/metabolismo , Tubarões/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Bioacumulação , Monitoramento Ambiental/métodos , Comportamento Alimentar , Humanos , Isótopos , Mercúrio/análise , Isótopos de Mercúrio , Músculos/química , Alimentos Marinhos , Tubarões/fisiologia , Poluentes Químicos da Água/análise
3.
J Environ Manage ; 287: 112260, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33714731

RESUMO

Unscientific urbanization in coastal cities has enforced the need for understanding groundwater recharge sources and processes for sustainable development. In this paper, stable isotope compositions of precipitation, groundwater and river water were determined to understand the significant recharge sources of phreatic aquifers in the two differently urbanized environments, viz. urban and peri urban clusters of Kozhikode District, Kerala, and southern India. The two monsoon systems viz., southwest and northeast, are the major source of groundwater recharge in the region, but due to change in landuse pattern in the last decade has significantly altered groundwater recharge. Hence with the aid of stable isotope ratios of water, estimation of point recharge of rainwater to the groundwater in different hydrgeological setting of the area was done. The monsoon rains contributed 35% in the urban alluvial aquifers, up to 39% in the urban laterite aquifer and 42% in the peri urban laterite aquifer. An attempt was made to correlate the landuse changes in the past decade in the region with the groundwater availability.


Assuntos
Monitoramento Ambiental , Água Subterrânea , Cidades , Índia , Isótopos/análise
4.
FEMS Microbiol Ecol ; 97(5)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33784375

RESUMO

The frequent exposure of agricultural soils to pesticides can lead to microbial adaptation, including the development of dedicated microbial populations that utilize the pesticide compound as a carbon and energy source. Soil from an agricultural field in Halen (Belgium) with a history of linuron exposure has been studied for its linuron-degrading bacterial populations at two time points over the past decade and Variovorax was appointed as a key linuron degrader. Like most studies on pesticide degradation, these studies relied on isolates that were retrieved through bias-prone enrichment procedures and therefore might not represent the in situ active pesticide-degrading populations. In this study, we revisited the Halen field and applied, in addition to enrichment-based isolation, DNA stable isotope probing (DNA-SIP), to identify in situ linuron-degrading bacteria in linuron-exposed soil microcosms. Linuron dissipation was unambiguously linked to Variovorax and its linuron catabolic genes and might involve the synergistic cooperation between two species. Additionally, two novel linuron-mineralizing Variovorax isolates were obtained with high 16S rRNA gene sequence similarity to strains isolated from the same field a decade earlier. The results confirm Variovorax as a prime in situ degrader of linuron in the studied agricultural field soil and corroborate the genus as key for maintaining the genetic memory of linuron degradation functionality in that field.


Assuntos
Herbicidas , Linurona , Bélgica , Biodegradação Ambiental , DNA Bacteriano/genética , Isótopos , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo
5.
Mar Pollut Bull ; 166: 112230, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33711606

RESUMO

Twenty biota species were collected from the Northern Beibu Gulf to understand the heavy metal pollution status and biomagnification characteristics. Mean concentrations (µg/g) of Mn, Zn, Pb, Cr, Ni, As, Cu, and Cd in the biota species were 0.99, 38.33, 0.14, 0.079, 0.085, 51.10, 7.92, and 0.21, respectively. As levels in most biota species exceeded the corresponding guidelines. Crabs were detected with high metal accumulation ability for each heavy metal except Pb. The ranges of δ15N and δ13C in organisms were from 8.0‰ to 15.6‰ and from -21.4‰ to -15.6‰, respectively. Cr, Mn, Ni, and As showed potential biomagnification trends in the food webs. The EDI values of these elements decreased by the sequence of As > Zn > Cu > Mn > Cd > Pb > Ni > Cr. High THQ and CR values for As indicated a potential health risk by consumption of these aquatic products.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Organismos Aquáticos , China , Monitoramento Ambiental , Isótopos , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise
6.
Bioresour Technol ; 330: 124959, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33735729

RESUMO

The organics (C) and nitrogenous (N) pollutants removal paths by functional units in vegetation-activated sludge process (V-ASP) were investigated by using stable isotope probing and high-throughput sequencing for the first time. V-ASP system displayed superior treatment performance compared to conventional activated sludge system, as manifested by its greater C and N removal efficiencies, higher abundance of denitrifying and heterotrophic functional Genus, and better resistance to low temperature. Isotope δ13C and δ15N were continuously accumulated in plant roots allocated in the V-ASP, where suspended sludge demonstrated obviously higher C and N enrichment rates compared to the rhizosphere sludge. The mass balance estimation showed that bacterial dissimilation was the dominant removal paths for C (54.13%) and N (47.53%). The underlying pollutants removal paths evidenced the advantageous of V-ASP that is a high feasible and promising approach for decentralized wastewater treatment process.


Assuntos
Poluentes Ambientais , Purificação da Água , Isótopos , Nitrogênio , Esgotos , Eliminação de Resíduos Líquidos , Águas Residuárias
7.
Zhongguo Zhong Yao Za Zhi ; 46(3): 560-566, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33645020

RESUMO

This paper established the identification technology of the main root origin of three-year-old spring Panax notoginseng aiming at providing theoretical basis for the protection and traceability of geographical indication products of P. notoginseng. Forty-four samples of three-year-old spring P. notoginseng from Guangxi Baise, Yunnan Wenshan, Yunnan new cultivating regions. The stable isotopic ratios of carbon, nitrogen, hydrogen and oxygen were determined by elemental analysis and stable isotope mass spectrometer. Combined with Duncan multiple comparative analysis, fisher discriminant analysis and sequential discriminant analysis, a origin discriminant model for the main root of three-year-old spring P. notoginseng was established for 3 production areas of P. notoginseng. The geographical climate and environment of three production areas of P. notoginseng are obviously different. From Guangxi Baise-Yunnan Wenshan-Yunnan new cultivating regions, the longitude, average annual temperature and annual precipitation gradually decrease, and the elevation and latitude are increasing. The results of multiple comparative analysis showed that there were significant or very signi-ficant differences in the δ~(13)C,δ~(15)N,δ~2H,δ~(18)O of the main roots of P. notoginseng in three regions. The results of fisher's discriminant analysis and sequential discriminant analysis showed that the correct discriminant rates of the main roots of P. notoginseng for three regions were 80.05%,76.47% and 90.91%, respectively, based on four stable isotope ratios, with an average of 84.09%. Using stable isotope fingerprint and chemometrics method, we can distinguish the origin of the main raw materials and products of P. notoginseng.


Assuntos
Panax notoginseng , China , Geografia , Isótopos , Estações do Ano
8.
Exp Appl Acarol ; 83(3): 375-386, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33646483

RESUMO

Mountain scree habitats are intermediate habitats between the base of the soil and the bedrock. They are composed of a network of small cracks and voids, and are commonly situated at the lower levels of scree slopes. Their environment is defined by empty spaces inside the scree, the absence of light and photoperiod, low temperature, and resource poor conditions. Soil arthropod communities, their trophic structure as well as their use of basal resources in mountain scree are little studied despite the fact that they are important components of these systems. Here, we investigate stable isotope ratios (15N/14N, 13C/12C) of oribatid mites (Oribatida, Acari) to understand their trophic niches and their variation with depth (50 and 75 cm) at two mountain scree sites (Cerdacul Stanciului, Marele Grohotis) in the Romanian Carpathians. Further, we used existing data to investigate the reproductive mode of the species in that habitat, as this may be related to resource availability. We hypothesized that trophic niches of oribatid mites will not differ between the two mountain scree regions but will be affected by depth. We furthermore hypothesized that due to the resource poor conditions oribatid mite species will span a narrow range of trophic levels, and that species are sexual rather than parthenogenetic. Our results showed that (1) oribatid mite trophic structure only slightly differed between the two sites indicating that the trophic ecology of oribatid mites in scree habitats is consistent and predictable, (2) oribatid mite trophic structure did not differ between the two studied soil depths indicating that the structure and availability of resources that were used by oribatid mites in deeper scree habitats varies little with depth, (3) oribatid mite species spanned only three trophic levels indicating that the habitat is rather resource poor, and (4) that all studied oribatid mite species were sexual supporting the view that resource poor conditions favour sexual reproduction.


Assuntos
Artrópodes , Ácaros , Animais , Ecossistema , Isótopos , Solo
9.
Sci Total Environ ; 771: 144807, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33548700

RESUMO

The biodegradation of aniline is an important process related to the attenuation of aniline pollution at contaminated sites. Aniline contamination could occur in various pH (i.e., acidic, neutral, and alkaline) environments. However, little is known about preferred pH conditions of diverse aniline degraders at different sites. This study investigated the active aniline degraders present under contrasting pH environments using three aniline-contaminated cultures, namely, acidic sludge (ACID-S, pH 3.1), neutral river sediment (NEUS, pH 6.6), and alkaline paddy soil (ALKP, pH 8.7). Here, DNA-based stable isotope probing coupled with high-throughput sequencing revealed that aniline degradation was associated with Armatimonadetes sp., Tepidisphaerales sp., and Rhizobiaceae sp. in ACID-S; Thauera sp., Zoogloea sp., and Acidovorax sp. in NEUS; Delftia sp., Thauera sp., and Nocardioides sp. in ALKP. All the putative aniline-degrading bacteria identified were present in the "core" microbiome of these three cultures; however, only an appropriate pH may facilitate their ability to metabolize aniline. In addition, the biotic interactions between putative aniline-degrading bacteria and non-direct degraders showed different characteristics in three cultures, suggesting aniline-degrading bacteria employ diverse survival strategies in different pH environments. These findings expand our current knowledge regarding the diversity of aniline degraders and the environments they inhabit, and provide guidance related to the bioremediation of aniline contaminated sites with complex pH environments.


Assuntos
Bactérias , Microbiologia do Solo , Compostos de Anilina , Bactérias/genética , Biodegradação Ambiental , Sequenciamento de Nucleotídeos em Larga Escala , Concentração de Íons de Hidrogênio , Isótopos
10.
Mar Environ Res ; 165: 105246, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33535137

RESUMO

Skipjack tuna (Katsuwonus pelamis) sustain a large-scale fishery in the southwest Atlantic Ocean (SWA), but information about its foraging ecology in this region is still limited. Here we use carbon (δ13C) and nitrogen (δ15N) stable isotope analysis of muscle from individuals collected in 2017-2018 (n = 383) to quantify diet composition and characterize movement patterns. We found a relatively small degree of variation in δ13C (range: -18.9 to -16.5‰) in comparison to δ15N values (6.7-14.7‰). At higher latitudes in the southern area (30-34°S), individuals had higher mean (±SD) δ15N values (12.2 ± 1.3‰) in comparison to those collected in the northern area (9.7 ± 1.5‰) between 20-26°S. At the northern area, isotope mixing models with informative priors showed that lanternfish (median: 50%) and krill (31%) were the primary foods. In the southern area, lanternfish (53%), krill (23%) and small pelagic fish (23%) were the primary food sources. Spatial shifts in diet composition were related to warming events that likely resulted in low abundance of sardines in the northern area. The latitudinal pattern in skipjack and krill δ15N values mirrored that of regional zooplankton isoscapes, suggesting residency at the timescale of isotopic turnover for muscle (~2-4 months), and that geographical variation in the baseline isotopic composition can be exploited to characterize seasonal movements of skipjack and other top marine consumers in this region.


Assuntos
Isótopos , Atum , Animais , Oceano Atlântico , Isótopos de Carbono/análise , Ecologia , Pesqueiros , Isótopos de Nitrogênio/análise
11.
Chemosphere ; 273: 129754, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33524760

RESUMO

Direct charge transfer (DCT) and •OH attack played important roles in contaminant degradation by BDD electrochemical oxidation. Their separate contributions and potential bond-cleavage processes were required but lacking. Here, we carried out promising compound-specific isotope fractionation analysis (CSIA) to explore 13C and 2H isotope fractionation of atrazine (ATZ), followed by assessing the reaction pathway by BDD anode. The correlation of 2H and 13C fractionation allows to remarkably differentiate DCT process and •OH attack, with Λ values of 18.99 and 53.60, respectively. Radical quenching identified that •OH accounted for 79.0%-88.5% in the whole reaction. While CSIA methods provided biased results, which suggested that ATZ degradation exhibited two stages with •OH contributions of 24.6% and 84.3% respectively, confirming CSIA was more sensitive and provided more possibilities to estimate degradation processes. Combined with Fukui index and intermediate products identification, we deduced that dechlorination-hydroxylation mainly occurred in the first 30 min by DCT reaction. While lateral chain oxidation with C-N broken was the governing route once •OH was largely generated, with the production of DEA (m/z 188), DIA (m/z 174), DEIA (m/z 146) and DEIHA (m/z 128). Our results demonstrated that isotope fractionation can offer "isotopic footprints" for identifying the rate-limiting steps and bond breakage process, and opens new avenues for degradation pathways of contaminants.


Assuntos
Atrazina , Poluentes Químicos da Água , Fracionamento Químico , Dioxóis , Eletrodos , Isótopos , Oxirredução , Poluentes Químicos da Água/análise
13.
Nature ; 590(7844): 97-102, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33536651

RESUMO

Following early hypotheses about the possible existence of Arctic ice shelves in the past1-3, the observation of specific erosional features as deep as 1,000 metres below the current sea level confirmed the presence of a thick layer of ice on the Lomonosov Ridge in the central Arctic Ocean and elsewhere4-6. Recent modelling studies have addressed how an ice shelf may have built up in glacial periods, covering most of the Arctic Ocean7,8. So far, however, there is no irrefutable marine-sediment characterization of such an extensive ice shelf in the Arctic, raising doubt about the impact of glacial conditions on the Arctic Ocean. Here we provide evidence for at least two episodes during which the Arctic Ocean and the adjacent Nordic seas were not only covered by an extensive ice shelf, but also filled entirely with fresh water, causing a widespread absence of thorium-230 in marine sediments. We propose that these Arctic freshwater intervals occurred 70,000-62,000 years before present and approximately 150,000-131,000 years before present, corresponding to portions of marine isotope stages 4 and 6. Alternative interpretations of the first occurrence of the calcareous nannofossil Emiliania huxleyi in Arctic sedimentary records would suggest younger ages for the older interval. Our approach explains the unexpected minima in Arctic thorium-230 records9 that have led to divergent interpretations of sedimentation rates10,11 and hampered their use for dating purposes. About nine million cubic kilometres of fresh water is required to explain our isotopic interpretation, a calculation that we support with estimates of hydrological fluxes and altered boundary conditions. A freshwater mass of this size-stored in oceans, rather than land-suggests that a revision of sea-level reconstructions based on freshwater-sensitive stable oxygen isotopes may be required, and that large masses of fresh water could be delivered to the north Atlantic Ocean on very short timescales.


Assuntos
Água Doce/análise , Camada de Gelo/química , Oceanos e Mares , Regiões Árticas , Foraminíferos/isolamento & purificação , Fósseis , Sedimentos Geológicos/química , História Antiga , Isótopos/análise , Plâncton/isolamento & purificação , Protoactínio/análise , Tório/análise , Fatores de Tempo
14.
Environ Res ; 195: 110800, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33529648

RESUMO

Honey from Apis mellifera is a useful and inexpensive biomonitor for mapping metal distributions in urban centers. The sampling resolution of a biomonitoring survey (e.g., city versus global scale) determines which geochemical processes are reflected in the results. This study presents Pb isotopic compositions and metal concentrations in honey from around the world, sampled at varying resolutions: honey from Canada (n = 21), the United States (n = 111), Belgium (n = 25), and New Zealand (n = 10), with additional samples from Afghanistan, Brazil, Cuba, Germany, Liberia, Taiwan, and Turkey. Honey was sampled at high resolution in two uniquely different land-use settings (New York Metro Area and the Hawaiian island of Kaua'i), at regional-scale resolution in eastern North America (including the Great Lakes region), and Pb isotopic compositions of all samples were compared on a global scale. At high sampling resolution, metal concentrations in honey reveal spatially significant concentration gradients: in New York City, metals associated with human activity and city infrastructure (e.g., Pb, Sb, Ti, V) are more concentrated in honey collected within the city compared to honey from upstate New York, and metal concentrations in honey from Kaua'i suggest polluting effects of nearby agricultural operations. At lower resolution (regional and global scales), lead isotopic compositions of honey are more useful than metal concentrations in revealing large-scale Pb processes (e.g., the enduring legacy of global leaded gasoline use throughout the twentieth century) and the continental origin of the honey. Lead isotopic compositions of honey collected from N. America (especially from the eastern USA) are more radiogenic (206Pb/207Pb: 1.132-1.253, 208Pb/206Pb: 2.001-2.129) compared to European honey, and honey from New Zealand, which has the least radiogenic isotopic compositions measured in this study (206Pb/207Pb: 1.077-1.160, 208Pb/206Pb: 2.090-2.187). Thus, biomonitoring using honey at different resolutions reflects differing processes and, to some extent, a honey terroir defined by the Pb isotopic composition. The data presented here provide important (and current) global context for future studies that utilize Pb isotopes in honey. Moreover, this study exhibits community science in action, as most of the honey was collected by collaborators around the world, working directly with local apiarists and hobby beekeepers.


Assuntos
Mel , Animais , Abelhas , Bélgica , Brasil , Canadá , Cidades , Monitoramento Ambiental , Alemanha , Great Lakes Region , Mel/análise , Humanos , Isótopos , Chumbo , Cidade de Nova Iorque , Nova Zelândia , Taiwan , Turquia
15.
J Contam Hydrol ; 238: 103773, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33540239

RESUMO

Urban groundwater management requires a thorough and robust scientific understanding of flow and transport processes. 3H/3He apparent ages have been shown to efficiently help provide important groundwater-related information. However, this type of analysis is expensive as well as labor- and time-intensive, and hence limits the number of potential sampling locations. To overcome this limitation, we established an inter-relationship between 3H/3He apparent groundwater ages and 4He concentrations analyzed in the field with a newly developed portable gas equilibrium membrane inlet mass spectrometer (GE-MIMS) system, and demonstrated that the results of the simpler GE-MIMS system are an accurate and reliable alternative to sophisticated laboratory based analyses. The combined use of 3H/3He lab-based ages and predicted ages from the 3H/3He-4He age relationship opens new opportunities for site characterization, and reveals insights into the conceptual understanding of groundwater systems. For our study site, we combined groundwater ages with hydrochemical data, water isotopes (18O and 2H), and perchloroethylene (PCE) concentrations (1) to identify spatial inter-aquifer mixing between artificially infiltrated groundwater and water originating from regional flow paths and (2) to explain the spatial differences in PCE contamination within the observed groundwater system. Overall, low PCE concentrations and young ages occur when the fraction of artificially infiltrated water is high. The results obtained from the age distribution analysis are strongly supported by the information gained from the isotopic and hydrochemical data. Moreover, for some wells, fault-induced aquifer connectivity is identified as a preferential flow path for the transport of older groundwater, leading to elevated PCE concentrations.


Assuntos
Água Subterrânea , Tetracloroetileno , Monitoramento Ambiental , Hélio/análise , Isótopos/análise
16.
Sci Total Environ ; 773: 145653, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33582336

RESUMO

Hydrothermal vent represents an extreme environment where metal-enriched fluids are in contact with chemosymbiotic animals. In the present study, Zn isotopic compositions were determined in multiple tissues of three dominant hydrothermal vent mollusks (the mussel Bathymodiolus marisindicus and two gastropods Chrysomallon squamiferum and Gigantopelta aegis) collected from a hydrothermal vent field (Southwest Indian Ridge in the Indian Ocean). We found approximately 1.78‰ differences in the δ66Zn values among the three vent mollusks despite of their similar range of Zn concentrations. The significant variation in the δ66Zn values was considered to be indicative of different Zn uptake sources among the three species as a result of their morphological adaptations. Zinc uptake associated with symbiotic activities may be more relevant in the vent gastropods, whereas Zn uptake from hydrothermal fluids during filter-feeding may also play a role in the vent mussels. However, no significant difference in δ66Zn values was observed among tissues of any of the mollusks, showing the absence of Zn isotope fractionation during internal Zn transport. Our results demonstrated that variable Zn uptake pathways existed among different hydrothermal vent mollusks and could be differentiated by determining the Zn isotopic compositions in their tissues. We also highlight that Zn isotope ratios can be used to track Zn sources to the vent mollusks.


Assuntos
Fontes Hidrotermais , Animais , Brânquias , Oceano Índico , Isótopos , Moluscos , Zinco
17.
J Pharm Biomed Anal ; 196: 113935, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33548872

RESUMO

BACKGROUND: The present COVID-19 pandemic has prompted worldwide repurposing of drugs. The aim of the present work was to develop and validate a two-dimensional isotope-dilution liquid chromatrography tandem mass spectrometry (ID-LC-MS/MS) method for accurate quantification of remdesivir and its active metabolite GS-441524, chloroquine, hydroxychloroquine, lopinavir, ritonavir, favipiravir and azithromycin in serum; drugs that have gained attention for repurposing in the treatment of COVID-19. METHODS: Following protein precipitation, samples were separated with a two-dimensional ultra-high performance liquid chromatography (2D-UHPLC) setup, consisting of an online solid phase extraction (SPE) coupled to an analytical column. For quantification, stable isotope-labelled analogues were used as internal standards for all analytes. The method was validated on the basis of the European Medicines Agency bioanalytical method validation protocol. RESULTS: Detuning of lopinavir and ritonavir allowed simultaneous quantification of all analytes with different concentration ranges and sensitivity with a uniform injection volume of 5 µL. The method provided robust validation results with inaccuracy and imprecision values of ≤ 9.59 % and ≤ 11.1 % for all quality controls. CONCLUSION: The presented method is suitable for accurate and simultaneous quantification of remdesivir, its metabolite GS-441525, chloroquine, hydroxychloroquine, lopinavir, ritonavir, favipiravir and azithromycin in human serum. The quantitative assay may be an efficient tool for the therapeutic drug monitoring of these potential drug candidates in COVID-19 patients in order to increase treatment efficacy and safety.


Assuntos
Antivirais/sangue , Antivirais/uso terapêutico , /tratamento farmacológico , Isótopos/química , /efeitos dos fármacos , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/sangue , Alanina/análogos & derivados , Alanina/sangue , Amidas/sangue , Azitromicina/sangue , Cloroquina/sangue , Cromatografia Líquida/métodos , Furanos/sangue , Humanos , Hidroxicloroquina/sangue , Lopinavir/sangue , Pandemias/prevenção & controle , Pirazinas/sangue , Pirróis/sangue , Ritonavir/sangue , Espectrometria de Massas em Tandem/métodos , Triazinas/sangue
18.
Ecotoxicol Environ Saf ; 210: 111865, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33418154

RESUMO

Cd contamination in rice grains has become a topic of great concern because of the high health risks associated with the long-term consumption of Cd-contaminated rice. Identification of Cd sources in rice grains by scientific methods is important for controlling heavy metal pollution and protecting human health. Here, the Cd concentrations and Cd isotopic compositions of rice plants (root, stem, leaf, and grain) and topsoil, and possible pollution sources (agricultural fertilizers, industrial dust, and automobile exhaust) were analyzed using an instrument of inductively coupled plasma mass spectrometry (ICP-MS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The results showed variations in the Cd isotopes of different components of rice plants and the fractionation coefficient of rice grains relative to topsoil (Δ114/110Cdrice grains-topsoil = 0.25‰). The contributions of pollution sources to rice grains were realized by combining the Cd isotopic composition with an isotopic mixing model (Isosource). The analysis showed that all three possible pollution sources contributed to the Cd in the rice grains in the field, the average Cd contribution of industrial dust, agricultural fertilizers and automobile exhaust was 87%, 9%, and 4%, respectively. Our study provides a feasible method for the identification of pollution sources of Cd in rice grains at the field scale and demonstrates that Cd isotopic composition is one of the powerful tools to trace the pollution sources of Cd in crops.


Assuntos
Cádmio/análise , Grão Comestível/química , Oryza , Poluentes do Solo/análise , Cádmio/química , Fracionamento Químico , Poeira , Monitoramento Ambiental , Fertilizantes , Humanos , Indústrias , Isótopos/análise , Emissões de Veículos
19.
Sci Total Environ ; 769: 144533, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33482542

RESUMO

Numerous studies reporting a transient decrease in soil nitrous oxide (N2O) emissions after biochar amendment have mainly used short-term experiments. Thus, long-term field trials are needed to clarify the actual impact of biochar on N2O emissions and the underlying mechanisms. To address this, both a 15N18O labeling technique and gene analyses were applied to investigate how N2O production pathways and microbial mediation were affected by long term biochar amendment in field. Then, 1-octyne and 2-phenyl l-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) were used in combination with potassium chlorate to evaluate the relative contribution of ammonia-oxidizing bacteria (AOB) and archaea (AOA) to potential ammonia oxidation (PAO) and the associated N2O production. Acidic and alkaline greenhouse vegetable soils that had each received two separate treatments were collected (control, no biochar amendment; biochar, biochar amended in the field after 2 or 7 years). The results showed that biochar decreased N2O emissions by 48% in acidic soils and by 22% in alkaline soils compared to those in control. These results were explained by decreases in nitrifier denitrification- (by 74%) and heterotrophic denitrification-derived N2O production (by 58%), as further evidenced by a decrease in NO2- (by 87%) and the (nirK+nirS+fungal nirK):(nosZ-I + nosZ-II) ratio (by 5%) in both greenhouse vegetable soils. However, biochar increased nitrifier nitrification-derived N2O in both soils because of increases in pH and PAO, which were attributed to an increased abundance of AOB rather than AOA. The contribution of AOB to PAO (or N2O) exceeded 69% (or 68%) of the total in acidic soil and 88% (or 85%) of the total in alkaline soil after biochar amendment. Our findings demonstrated that the mitigation of N2O by biochar is linked to specific N2O production pathways.


Assuntos
Carvão Vegetal , Microbiologia do Solo , Desnitrificação , Isótopos , Nitrificação , Óxido Nitroso/análise , Solo
20.
Sci Total Environ ; 770: 145258, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33513516

RESUMO

Several recent studies showed that leaf wax n-alkane δ2H values (δ2Hwax) within a leaf were heterogeneous in a small number of species. It still remains unclear whether the heterogeneity of intra-leaf δ2Hwax values is general for various species, how δ2Hwax values vary spatially and temporally, and whether there is a common explanation for the intra-leaf δ2Hwax heterogeneity in higher plants. Here we compared the hydrogen isotope compositions of leaf wax and corresponding leaf water (δ2Hlw) across leaf sections among a variety of monocot and dicot plant species. There is significant and consistent heterogeneity for both δ2Hwax and δ2Hlw, i.e., base-to-tip 2H-enrichment for monocots (except Hemerocallis citrina, and Dactylis glomerata) whereas base-to-tip and center-to-edge increases in δ2Hwax and δ2Hlw for dicots. The consistent occurrence of variations of δ2Hlw and δ2Hwax values within a leaf imply that δ2Hwax values probably inherit point-to-pint from in-situ δ2Hlw values, and thus the intra-leaf δ2Hwax heterogeneity mainly results from the spatial pattern of intra-leaf δ2Hlw values associated with veinal structures between dicots and monocots. The general heterogeneity of intra-leaf δ2Hwax values further intensifies that it is necessarily needed for in-depth understanding leaf wax biomarker.


Assuntos
Hidrogênio , Água , Isótopos , Folhas de Planta , Ceras
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