Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.698
Filtrar
1.
Food Chem ; 303: 125378, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450176

RESUMO

This work introduces an inexpensive and user-friendly electrochemical platform for heavy metal determination in liquid food. Smart-phone connectivity, solid-state-microwave flow digestion and nano-Au-modified electrode are synchronously studied. A smart phone is adopted as the information terminal for universal purposes. A solid-state-microwave digestion device is developed to provide programmable digestion for liquid food in a digestion path. Microwave power curve and flow rate in digestion are studied and optimized. A nano-Au-modified electrode, as well as a homemade potentiostat and other electrodes, is used as a tool for electrochemical analyses. Behaviors of this method are evaluated with electrical measurement and stripping voltammetry. This method is used for sensing Cd2+, Pb2+ and Hg2+ in cow milk, orange juice and apple juice. It provides a sensitive response to ≥2 µg L-1 target ion, and shows satisfying stability and good accuracy in a task up to 72 h.


Assuntos
Técnicas Eletroquímicas/métodos , Sucos de Frutas e Vegetais/análise , Metais Pesados/análise , Leite/química , Smartphone , Animais , Cádmio/análise , Bovinos , Eletrodos , Feminino , Ouro/química , Chumbo/análise , Mercúrio/análise , Micro-Ondas
2.
Sci Total Environ ; 692: 1116-1124, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539943

RESUMO

Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg0) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg0. It is proposed that oxidative complexation between Hg0 and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg2+-thiolate complexes and HgS during the binding of Hg0 with BioSeNPs. The formation of mercury selenide was also involved in Hg0 immobilization in the porous quartz sand system.


Assuntos
Mercúrio/análise , Modelos Químicos , Nanopartículas/análise , Selênio/análise , Biofilmes , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Quartzo , Selênio/química
3.
Environ Pollut ; 254(Pt B): 113064, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31479810

RESUMO

Mercury pollution is currently a major public health concern, given the adverse effects of mercury on wildlife and humans. Soil plays an essential role in speciation of mercury and its global cycling, while being a habitat for a wide range of terrestrial fauna. Soil fauna, primarily soil-feeding taxa that are in intimate contact with soil pollutants are key contributors in the cycling of soil mercury and might provide relevant indications about soil pollution. We studied the enrichment of various mercury species in the nests and bodies of soil-feeding termites Silvestritermes spp. in French Guiana. Soil-feeding termites are the only social insects using soil as both shelter and food and are major decomposers of organic matter in neotropical forests. Nests of S. minutus were depleted in total and mobile mercury compared to nearby soil. In contrast, they were enriched 17 times in methylmercury. The highest concentrations of methylmercury were found in body of both studied termite species, with mean bioconcentration factors of 58 for S. minutus and 179 for S. holmgreni relative to the soil. The assessment of the body distribution of methylmercury in S. minutus showed concentrations of 221 ng g-1 for the guts and even higher for the gut-free carcasses (683 ng g-1), suggesting that methylmercury is not confined to the gut where it was likely produced, but rather stored in various tissues. This enrichment in the most toxic form of Hg in termites may be of concern on termite predators and the higher levels in the food chain that may be endangered through prey-to-predator transfers and bioaccumulation. Soil-feeding termites appear to be promising candidates as bio-indicators of mercury pollution in soils of neotropical rainforest ecosystems.


Assuntos
Isópteros/fisiologia , Mercúrio/análise , Poluentes do Solo/análise , Animais , Animais Selvagens , Ecossistema , Monitoramento Ambiental , Cadeia Alimentar , Florestas , Guiana Francesa , Humanos , Isópteros/metabolismo , Compostos de Metilmercúrio , Floresta Úmida , Solo
4.
Environ Monit Assess ; 191(10): 622, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31494726

RESUMO

Bioleaching of heavy metals from industrial contaminated soil using metallotolerant fungi is the most efficient, cost-effective, and eco-friendly technique. In the current study, the contaminated soil samples from Hattar Industrial Estate revealed a total lead (Pb) and mercury (Hg) concentration of 170.90 mg L-1 and 26.66 mg L-1, respectively. Indigenous metallotolerant fungal strains including Aspergillus niger M1, Aspergillus fumigatus M3, Aspergillus terreus M6, and Aspergillus flavus M7 were isolated and identified by pheno- and genotyping. A. fumigatus and A. flavus of soil sample S1 showed higher efficiency for Pb removal (99.20% and 99.30%, respectively), in SDB medium. Likewise, A. niger and A. terreus of soil sample S2 showed higher efficiency for Hg removal (96% and 95.50%, respectively), in YPG medium. Furthermore, the maximum uptake efficiency for Pb removal (8.52 mg g-1) from soil sample S1 was noticed for A. fumigatus in YPG medium, while the highest uptake efficiency (4.23 mg g-1) of A. flavus M2 strain was observed with CYE medium. Similarly, the maximum uptake efficiency of 0.41 mg g-1 and 0.44 mg g-1 for Hg removal from soil sample S2 was found for A. niger and A. terreus strains, respectively, in CYE medium. Thus, in order to address the major issue of industrial waste pollution, indigenous fungal strains A. fumigatus (M1) and A. terreus (M7), isolated in this study, could be used (ex situ or in situ) to remediate soils contaminated with Pb and Hg.


Assuntos
Aspergillus/metabolismo , Chumbo/metabolismo , Mercúrio/metabolismo , Metais Pesados/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Aspergillus/classificação , Aspergillus/genética , Monitoramento Ambiental , Recuperação e Remediação Ambiental , Genótipo , Resíduos Industriais , Chumbo/análise , Mercúrio/análise , Metais Pesados/análise , Fenótipo , Poluentes do Solo/análise
5.
Bull Environ Contam Toxicol ; 103(4): 617-622, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31471658

RESUMO

Tree foliage sequesters gaseous elemental mercury (Hg) through stomatal uptake, when the foliage senesces and falls into the water, Hg from leaf litter can be released into the water and/or microbially methylated into a highly toxic form, methylmercury. The dominant groups of microbial communities that can methylate Hg during litter decomposition are, however, less certain. We conducted a microbial inhibition experiment to identify the primary methylators of leaf litter Hg during 28-day decomposition of two litter species of contrasting quality (pine and maple). We demonstrate that sulfate-reducing bacteria are the dominant microbial groups for Hg methylation during anoxic litter decomposition, and our study also indicates that methanogens may have a minor role in mediating Hg methylation during litter decomposition. Thus, aquatic environment with extensive litter accumulation and decomposition (e.g., wetlands, ponds, and river pools) can be hotspots of Hg methylation through sulfate-reduction and, to a lesser extent, methanogenesis.


Assuntos
Mercúrio/metabolismo , Compostos de Metilmercúrio/metabolismo , Poluentes do Solo/metabolismo , Mercúrio/análise , Metilação , Tanques , Rios , Árvores/metabolismo , Água , Áreas Alagadas
6.
Environ Monit Assess ; 191(10): 607, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31485756

RESUMO

The geochemical fractions of heavy metals in sediments are crucial indexes for their mobility and bioavailability evaluations. However, different drying processes of sediment pretreatment could change metal geochemical fractions, especially for Hg, which is potentially volatile. In this study, the influence of pretreatment methods including oven-drying, air-drying, freeze-drying, and fresh sediments on the analysis of Hg fractions in sediments was investigated. Results showed that remarkable differences of Hg concentration were observed between fresh sediments and dried pretreatment sediments (P < 0.05). Briefly, the concentrations of the water-soluble and human stomach acid-soluble fractions in oven-dried and air-dried sediments generally showed significant increasing trends compared with those in the fresh sediments, while the organo-chelated fraction exhibited significant decreasing trends. The cause of this phenomenon was primarily the oxidation of organic matter, aging process, and the diffusion of Hg into micropores. The significant loss was also observed at elemental Hg fraction due to its volatilization effect. The freeze-drying posed minor influence on changes of Hg fraction analysis compared with oven-drying and air-drying. Moreover, the total Hg concentrations in pretreated sediments showed a decline of varying degrees compared with those in fresh sediments ascribing to the volatilization of elemental Hg. Finally, Pearson correlation analysis further confirmed that freeze-drying could minimize the errors of the Hg fraction analysis in sediments.


Assuntos
Dessecação , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Mercúrio/análise , Disponibilidade Biológica , Poluentes do Solo/análise , Volatilização
7.
Biotechnol Appl Biochem ; 66(5): 731-737, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31411759

RESUMO

Mercury ion (Hg2+ ) is a universal pollutant and its detection is crucial for public healthcare. In this study, we developed a novel fluorescent biosensor by construction of a protein fusion between the mercury-sensing transcription factor MerR and enhanced yellow fluorescent protein (EYFP). Hg2+ -induced conformational change of MerR was transduced into fluorescence signal. Fluorescence intensity of the biosensor protein decreased with increasing concentrations of Hg2+ and a linear response was obtained in the range of 0.5-40 nM. The limit of detection was 0.5 nM, which was much lower than the maximum allowed level in water. The biosensor specificity was highly dependent on type and concentration of metal ion. The biosensor exhibited high specificity in a mixture of metal ions at 0.5 nM concentration. However, the interference effect was more pronounced at 40 nM concentration of metal ions. The measurement was completed in less than 1 Min with no need for sample preparation or preincubation steps. The biosensor achieved accurate and reliable detection in the spiked drinking water sample, as validated by the inductively coupled plasma optical emission spectrometry.


Assuntos
Proteínas de Bactérias/química , Técnicas Biossensoriais , Proteínas de Ligação a DNA/química , Água Potável/química , Proteínas Luminescentes/química , Mercúrio/análise , Fluorescência , Imagem Óptica
8.
Sci Total Environ ; 686: 1120-1128, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412508

RESUMO

Polar bears (Ursus maritimus) are an ecologically important species in the Arctic, whose health, and that of the people whose livelihoods depend on them, are increasingly affected by climate change and the bioaccumulation of contaminants such as mercury (Hg). Although methylmercury (MeHg) is the toxic form of Hg that biomagnifies up food webs, risk assessment studies typically only report on total Hg (THg) concentrations because it is cheaper to quantify. Furthermore, hair is commonly analysed for THg in polar bear as well as human risk assessment studies because it is relatively non-invasive to collect, yet we know little of how THg and MeHg concentrations differ between hair and muscle tissues. In this study, we quantified THg and MeHg concentrations in hair and muscle from 44 polar bears (24 sub-adults: 9 females, 15 males; 18 adults: 5 females, 13 males, and 2 males of unknown age group), harvested in 2015 and 2016 from four subpopulations in Nunavut, Canada (Davis Strait, n = 3; Gulf of Boothia, n = 8; Baffin Bay, n = 15; Foxe Basin, n = 18). We found only moderately positive correlations (0.4 ≤ r ≤ 0.5) between THg concentrations in hair and THg and MeHg concentrations in muscle. Further, 75% and 88% of THg was MeHg in hair and muscle, respectively. High concentrations of THg in hair - 71% of the samples were above the suggested neurochemical no observed effect level for polar bears - suggest some of the bears may be adversely affected by Hg-related health effects. Despite this, all MeHg concentrations in muscle (0.1 to 0.4 mg/kg (wet weight, ww)) were below the consumption maximum Hg concentration of 0.5 mg/kg (ww) set by Canadian health authorities.


Assuntos
Monitoramento Ambiental/métodos , Cabelo/química , Mercúrio/análise , Compostos de Metilmercúrio/análise , Músculos/química , Ursidae/metabolismo , Animais , Regiões Árticas , Feminino , Humanos , Masculino , Nunavut , Medição de Risco
9.
Environ Monit Assess ; 191(9): 545, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31392424

RESUMO

Mercury (Hg) emission from natural soil is one of the most important contributors to global Hg cycles. Research on Hg emission from soil to air has been carried out in China. Currently, most of the research focuses on contaminated sites in China, while research in other regions is rare. To provide more accurate information on Hg emissions from soil to air in China and obtain additional laboratory data to verify the role of solar radiation and temperature in this process, we sampled and measured Hg emission fluxes from various natural soils (range, 48-240 ng/g) across mainland China under different solar radiation (0-900 W·m-2) and temperature (15-45 °C) conditions in a laboratory. We found that in different places in China, Hg emissions from natural soils occurred more easily when the soil Hg concentration, temperature, and solar radiation were high, but the impacts were different among the regions due to different soil types. Hg emissions from natural soils (0.071-24 ng·m2·h-1) were typically lower than those from contaminated sites, suggesting that additional measurements in natural soils are desirable. The results of this study could provide more accurate information on Hg emission from natural soil to air and help establish a nationwide natural soil Hg emission inventory in China.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Mercúrio/análise , Poluentes do Solo/análise , Solo/química , China , Temperatura Ambiente
10.
Environ Monit Assess ; 191(9): 566, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31418123

RESUMO

Mercury (Hg) is a pollutant that poses a global threat, and it was listed as one of the ten leading 'chemicals of concern' by the World Health Organization in 2017. The review aims to summarize the sources of Hg, its combined effects on the ecosystem, and its remediation in the environment. The flow of Hg from coal to fly ash (FA), soil, and plants has become a serious concern. Hg chemically binds to sulphur-containing components in coal during coal formation. Coal combustion in thermal power plants is the major anthropogenic source of Hg in the environment. Hg is taken up by plant roots from contaminated soil and transferred to the stem and aerial parts. Through bioaccumulation in the plant system, Hg moves into the food chain, resulting in potential health and ecological risks. The world average Hg concentrations reported in coal and FA are 0.01-1 and 0.62 mg/kg, respectively. The mass of Hg accumulated globally in the soil is estimated to be 250-1000 Gg. Several techniques have been applied to remove or minimize elevated levels of Hg from FA, soil, and water (soil washing, selective catalytic reduction, wet flue gas desulphurization, stabilization, adsorption, thermal treatment, electro-remediation, and phytoremediation). Adsorbents such as activated carbon and carbon nanotubes have been used for Hg removal. The application of phytoremediation techniques has been proven as a promising approach in the removal of Hg from contaminated soil. Plant species such as Brassica juncea are potential candidates for Hg removal from soil.


Assuntos
Poluentes Ambientais/análise , Poluentes Ambientais/toxicidade , Recuperação e Remediação Ambiental/métodos , Mercúrio/análise , Mercúrio/toxicidade , Biodegradação Ambiental , Carvão Mineral/análise , Cinza de Carvão/análise , Monitoramento Ambiental/métodos , Mostardeira/crescimento & desenvolvimento , Nanotubos de Carbono/química , Centrais Elétricas , Solo/química
11.
Arch Environ Contam Toxicol ; 77(3): 336-343, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31384978

RESUMO

We collected Walleye Sander vitreus (May-October) from Bitter and Twin lakes, South Dakota to assess seasonal- and diet-related variation in tissue mercury (Hg) concentration. The average Hg concentration in Walleye was 43-68% higher in the spring for Bitter (p < 0.008) and Twin Lakes (p < 0.017) compared with summer or autumn months. Bioenergetics analysis of Bitter Lake Walleye showed that consumption of fish prey (primarily Fathead Minnow Pimephales promelas) increased from late summer through winter and was linked to increased Hg accumulation in Walleye the following spring. Mercury concentration varied significantly with Walleye age but was similar for comparably-aged male (0.62 µg/g) and female fish (0.62 µg/g). However, after adjusting for Walleye size (total length, mm), mean Hg concentration was greater in male (0.66 µg/g) compared with female (0.50 µg/g) fish, likely due to slower growth rate of male Walleye. At 425 mm, male Walleye in Bitter Lake were approximately 1 year older than female fish. These findings show that diet, age, and gender-related growth affect Hg concentration in Walleye and are important factors to consider in fish contaminant monitoring programs.


Assuntos
Mercúrio/análise , Percas , Poluentes Químicos da Água/análise , Fatores Etários , Animais , Tamanho Corporal , Dieta , Ecotoxicologia/métodos , Monitoramento Ambiental/métodos , Feminino , Lagos , Masculino , Percas/fisiologia , Comportamento Predatório , Estações do Ano , South Dakota
12.
Mar Pollut Bull ; 146: 442-453, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426179

RESUMO

This paper reports long-term concentration records of metals and organic halogenated compounds in tissues of 49 species of marine organisms from Eastern South Pacific coast, Biobio region, Chile during a marine monitoring program developed between 2006 and 2015. Principal component (PCA) and generalized linear model (GLM) analyses indicated significant differences in the concentrations of metals and organic halogenated compounds among taxonomic and functional groups. The strongest relationships exist between species that share similar feeding habits rather than between species of the same taxonomic group or habitat. The significant differences between these groups were maintained over time; thus concentrations detected are, in general, within the ranges reported at genus level for Chile and the rest of the world. Since there is no evidence of any pollution process in the area, this information can be used as an environmental reference to establish natural concentrations for the parameters and organisms analyzed.


Assuntos
Organismos Aquáticos/química , Monitoramento Ambiental , Halogênios/análise , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Biota , Cádmio/análise , Chile , Halogenação , Chumbo/análise , Mercúrio/análise , Compostos Orgânicos/análise , Dibenzodioxinas Policloradas/análise , Zinco/análise
13.
Mar Pollut Bull ; 146: 466-475, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426182

RESUMO

Ecological risk assessment of metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in surface sediments from 31 small craft harbours (SCHs) in Nova Scotia, Canada was conducted using multiple risk assessment approaches. Approaches used were contamination factor, pollution load index, geoaccumulation index, potential ecological risk factor for individual metals, comprehensive potential ecological risk index, mean probable effect level quotient and mean effects range median quotient. Results indicated most SCHs exhibited low ecological risk from sediment metal concentrations, except for two harbours. Metal contamination was highest in Canso Harbour, followed by Clarks Harbour. SCH sediments were only slightly contaminated with low probability of pollution according to mean probable effect level and mean effects range median quotients. However, pollution load and geoaccumulation indexes indicated Cd and Hg had the highest metal contamination across SCH sediments. Cadmium and Hg had the highest potential ecological risk, respectively compared to other metals.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos , Metais/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Animais , China , Monitoramento Ambiental/métodos , Mercúrio/análise , Metais/toxicidade , Nova Escócia , Medição de Risco , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/toxicidade
14.
Environ Pollut ; 254(Pt B): 113065, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31465902

RESUMO

Forest ecosystem has long been suggested as a vital component in the global mercury (Hg) biogeochemical cycling. However, there remains large uncertainties in understanding total Hg (THg) and methylmercury (MeHg) variations and their controlling factors during the whole hydrological processes in forest ecosystems. Here, we quantified Hg mass flow along hydrological processes of wet deposition, throughfall, stemflow, litter leachate, soil leachate, surface runoff, and stream, and litterfall Hg deposition, and air-forest floor elemental Hg (Hg0) exchange flux to set up a Hg mass balance in a subtropical forest of China. Results showed that THg concentration in stream was lower than that in wet deposition, while an opposite characteristic for MeHg concentration, and both THg and MeHg fluxes of stream were lower than those of wet deposition. Variations of THg and MeHg in throughfall and litter leachate had strong direct and indirect effects on controlling variations of THg and MeHg in surface runoff, soil leachate and stream, respectively. Especially, the net Hg methylation was suggested in the forest canopy and forest floor layers, and significant particulate bound Hg (PBM) filtration was observed in soil layers. The Hg mass balance showed that the litterfall Hg deposition was the main Hg input for forest floor Hg, and the elemental Hg vapor (Hg0) re-emission from forest floor was the dominant Hg output. Overall, we estimated the net THg input flux of 13.8 µg m-2 yr-1 and net MeHg input flux of 0.6 µg m-2 yr-1 within the forest ecosystem. Our results highlighted the important roles of forest canopy and forest floor to shape Hg in output flow, and the forest floor is a distinct sink of MeHg.


Assuntos
Monitoramento Ambiental , Mercúrio/análise , Poluentes Químicos da Água/análise , China , Ecossistema , Florestas , Hidrologia , Compostos de Metilmercúrio , Rios , Solo
15.
Ecotoxicol Environ Saf ; 183: 109469, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31376803

RESUMO

Botafogo river estuary poses the highest Hg concentration reported for mangrove soils in Brazil. Such high contamination took place owing to the improper waste disposal for 24 years from a chlor-alkali plant nearby the estuary. Here we determined Hg concentrations in soils, mangrove plants (Rhizophora mangle and Laguncularia racemosa), and an aquatic organism (the oyster species Crassostrea rhizophorae) to assess Hg bioavailability. Besides, a sequential extraction procedure was used to separate soil Hg into five fractions: water-soluble; 'human stomach acid' soluble; organically bound; elemental Hg; mercuric sulfide. Results showed that environmentally available concentration of Hg in the mangrove soils were up to 150-fold higher than a pristine mangrove under the same geological context used as a reference. Additionally, Hg concentration in soils was also above sediment quality guidelines and Hg adverse effects towards sensitive estuarine organisms are likely. Mercury concentrations in oysters were the highest reported in Brazil, but within safety standards according to the country food security agency. It seems that Hg stocks in the studied soils are governed by organic matter and redox conditions, but changing on environmental conditions and land use can alter this balance and convert these mangrove areas from sink to source of Hg to the environment.


Assuntos
Organismos Aquáticos/química , Monitoramento Ambiental/métodos , Mercúrio/análise , Poluentes do Solo/análise , Áreas Alagadas , Animais , Organismos Aquáticos/efeitos dos fármacos , Disponibilidade Biológica , Brasil , Indústria Química , Estuários , Humanos , Ostreidae/química , Ostreidae/efeitos dos fármacos , Rhizophoraceae/química , Rhizophoraceae/efeitos dos fármacos , Rios/química , Solo/química
16.
Sci Total Environ ; 695: 133791, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31419679

RESUMO

The atoll of Hao, part of the Tuamotu Archipelago in French Polynesia, hosted an air base which was used by France Air Force and Naval Aviation during the nuclear tests. Following the publication of a report in 2012 indicating widespread contamination of the atoll, we conducted a biomonitoring survey to assess the exposure to toxic metals and polychlorinated biphenyls (PCBs) of Hao residents and residents of Makemo, a nearby atoll without any known sources of industrial pollution. Adults and adolescents (≥12 years) randomly sampled from Hao (n = 275) and Makemo (n = 268) provided blood samples for contaminant analyses. Whole blood samples were analysed for cadmium, lead and total mercury by inductively coupled plasma mass spectrometry. Plasma concentrations of PCBs were measured by gas chromatography mass spectrometry. Face-to-face interviews were conducted to document lifestyle and a food-frequency questionnaire was used to document dietary habits. Concentrations of contaminants were compared between atolls and associations with sociodemographic and personal characteristics of the participants were investigated. A significantly higher mean (geometric) of blood lead concentration was observed in Hao compared to Makemo (3.75 vs 3.40 µg/L, P = 0.02), whereas similar concentrations were noted for cadmium (0.49 vs 0.50 µg/L, P = 0.58) and mercury (11.4 vs 11.5 µg/L, P = 0.78). Mean total PCBs plasma concentration was significantly higher in Hao than in Makemo participants (0.75 vs 0.32 µg/L, P < 0.001). A significant proportion of participants exceeded toxicological reference values for mercury and lead in both atolls. The higher body burden of PCBs and Pb in Hao compared to Makemo residents may be linked to past air base activities in Hao. According to international standards, PCBs exposure is low; however, exposure to both mercury and lead is high and further investigations are required to identify specific sources of exposure.


Assuntos
Exposição Ambiental/análise , Poluentes Ambientais/sangue , Poluição Ambiental/estatística & dados numéricos , Metais/sangue , Bifenilos Policlorados/sangue , Adolescente , Adulto , Cádmio/análise , Poluentes Ambientais/análise , Humanos , Chumbo/análise , Mercúrio/análise , Metais/análise , Bifenilos Policlorados/análise , Polinésia
17.
Environ Pollut ; 254(Pt B): 113048, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31454580

RESUMO

The inorganic content of the well-preserved 3.2-m record of Las Conchas bog (NW Spain), covering 8000 cal yr BP., was analysed. To study natural vs. human contributions, we applied an innovative approach, namely the sequential study of multivariate statistics (factor analysis followed by clustering of the factor score matrix) and enrichment factors (EFs). The increasing weight of potentially toxic elements (PTEs) such as the geochemical association of Zn, Pb and Cd (EFs higher than 10, 20 and 40 in the last two centuries) was revealed, and corroborated by the contrast between the contents of anthropogenic Pb and total Rare Earth Elements (a suitable proxy for natural geogenic supplies). Furthermore, elements such as Hg, Tl and As also showed enrichment in the most recent samples of the study core. Some of them are commonly associated with global atmospheric transport; however, in this case, their increasing contents could also be explained by nearby industrial and mining activities. In summary, severe pollution was observed in the uppermost part of the record, thereby pointing to an important environmental concern. Given that local and regional sources of PTEs, such as mining and heavy industry, especially Zn smelting, were probably the main historical causes of this contamination and that some of these industries are still active, we consider that our findings deserve further attention.


Assuntos
Monitoramento Ambiental , Poluentes do Solo/análise , Poluição Ambiental/análise , Humanos , Mercúrio/análise , Metalurgia , Metais Pesados/análise , Mineração , Medição de Risco , Solo/química , Espanha , Áreas Alagadas
18.
Environ Pollut ; 254(Pt B): 113049, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31454582

RESUMO

This study aimed to determine if there is a co-elevation of human blood arsenic and mercury levels in the Midwestern population of the United States (U.S.) and to determine any geographical patterns and variation of arsenic and mercury that may exist in Michigan. 58,800 blood specimens along with associated demographic/geographic data from the contiguous United States were reviewed. Univariate and multivariable logistic regression were used to analyze demographic/geographic variables associated with elevated arsenic concentrations. Furthermore, blood data from patients in Michigan were aggregated to the ZIP code tabulation area (ZCTA) in order to assess geographic variation using spatial regression models. SaTScan software was also used to analyze potential clustering of arsenic and mercury across Michigan ZCTAs. Within the contiguous United States, elevated mercury blood concentrations, older age, female sex, and coastal status were all associated with elevated arsenic blood concentrations (elevated mercury odds ratio (OR) 3.18 (3.04-3.33); female sex OR 1.06 (1.02-1.11); +10 yr age OR 1.12 (1.11-1.14); coastal state OR 1.33 (1.27-1.40). Within the state of Michigan, as with the continuous U.S., elevated mercury blood concentrations and older age were associated with elevated arsenic blood concentrations (elevated mercury OR 2.75 (2.38-3.18); female sex OR 1.06 (0.95-1.19); +10 yr age OR 1.10 (1.06-1.13). Using spatial regression, it was determined that within Michigan, economic inequality (measured via the Gini coefficient) was also associated with elevated concentrations of mercury in the blood. Clinical reference laboratory data, in conjunction with spatial analysis methods, may enhance our understanding of how elemental exposure affects human health and should be considered for studying how environmental contaminants, socioeconomics and geography affect the health of populations.


Assuntos
Arsênico/análise , Exposição Ambiental/análise , Mercúrio/análise , Adulto , Idoso , Exposição Ambiental/estatística & dados numéricos , Feminino , Geografia , Humanos , Masculino , Michigan , Pessoa de Meia-Idade , Estados Unidos
19.
Environ Pollut ; 254(Pt B): 113034, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31465904

RESUMO

Bats are particularly suited as bioindicators of trace element pollution due to their longevity and their position in the trophic chain. In this study, the concentrations of ten non-essential trace elements (Al, As, Ba, Cd, Hg, Pb, Sb, Sr, Th, Tl) were determined in the tissues (whole body, skin-fur, skinned body, liver, kidney and bone) of lactant Tadarida teniotis from a nursery colony in Rome. A large number of bats from this nursery died before fledging and had bone deformities and fractures. The concentrations of non-essential trace elements in bone and whole body were also analysed in adult specimens of Miniopterus schreibersii from a colony located in a natural park in Northern Italy. In lactant T. teniotis, the Pb concentration decreased in the following order: bone>liver>skinned body>whole body>skin-fur>kidney, and exceeded the toxic threshold associated with negative effects reported for different mammalian species. The levels of the other non-essential trace elements were within a range indicative of low environmental contamination in both species. Significant interspecies differences (P < 0.05) were observed for concentrations of Pb and Ba, higher in the bones of T. teniotis, and of Cd, Hg and Sr, higher in the bones of M. schreibersii. In lactant T. teniotis, the different sources of Pb exposure, through inhalation and/or food, may represent a potential threat to the colony of this synanthropic European bat.


Assuntos
Quirópteros/metabolismo , Exposição Ambiental/análise , Oligoelementos/análise , Animais , Monitoramento Ambiental , Itália , Rim/química , Fígado/química , Mercúrio/análise , Roma , Oligoelementos/metabolismo , Urbanização
20.
Mar Pollut Bull ; 146: 955-961, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426243

RESUMO

Mercury and selenium were measured for first time in the endangered species whale shark (Rhyncodon typus) from two areas of the Gulf of California, Bahía Los Angeles (BLA) and Bahía La Paz (LAP) using dermal biopsies of seventy specimens. Additionally, nineteen zooplankton samples from LAP were analysed. Concentrations (ng/g, wet weight (ww)) in biopsies of BLA ranged from 1 to 40 for Hg and 100 to 680 for Se; while in LAP varied from 1 to 9 for Hg and 11 to 850 for Se. A positive correlation was found for Hg in BLA males biopsies with length. Hg and Se concentrations in the zooplankton from LAP were 1.6 ±â€¯1.8 and 770 ±â€¯930 ng/g, respectively. Hg biomagnification factor ranged from 0.8 to 5.3 in sharks. A molar excess of Se over Hg was found in the biopsies and the zooplankton.


Assuntos
Mercúrio/metabolismo , Selênio/metabolismo , Tubarões/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Espécies em Perigo de Extinção , Feminino , Masculino , Mercúrio/análise , México , Selênio/análise , Poluentes Químicos da Água/análise , Zooplâncton/química , Zooplâncton/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA