Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.697
Filtrar
1.
Chemosphere ; 238: 124581, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31445333

RESUMO

Lead (Pb) pollution is one of the most serious environmental problems and has attracted worldwide attention. Pb causes hematological, central nervous system, as well as renal toxicity, and so on. Although many investigations about Pb in blood to evaluate pollution status and toxic effects have been reported, there are open question about biological behavior of Pb. In order to reveal any toxicological mechanisms or influences, we focused on the local distribution of Pb in mice organs. Lead acetate (100 mg/L and 1000 mg/L) in drinking water were given to the BALB/c mice (male, seven weeks of age, N = 24) for three weeks. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis revealed a homogenous distribution of Pb in the liver and inhomogeneous distribution in the kidney and brain. The hippocampus, thalamus, and hypothalamus had higher concentrations than other areas such as the white matter. Surprisingly, in the kidney, Pb tended to accumulate in the medulla rather than the cortex, strongly suggesting that high sensitivity areas and high accumulation areas differ. Moreover, distribution of stromal interacting protein 1 (STIM1) which is candidate gene of Pb pathway to the cells was homogenous in the liver and kidney whereas inhomogeneous in the brain. In contrast to our hypothesis, interestingly, Pb exposure under the current condition did not induce mRNA expressions for any candidate channel or transporter genes. Thus, further study should be conducted to elucidate the local distribution of Pb and other toxic metals, and pathway that Pb takes to the cells.


Assuntos
Química Encefálica/efeitos dos fármacos , Rim/química , Chumbo/análise , Fígado/química , Molécula 1 de Interação Estromal/análise , Animais , Encéfalo/metabolismo , Imuno-Histoquímica/métodos , Terapia a Laser , Masculino , Espectrometria de Massas/métodos , Camundongos , Camundongos Endogâmicos BALB C , Análise Espectral
2.
Ecotoxicol Environ Saf ; 187: 109763, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31644987

RESUMO

An eco-friendly corncob biochar based montmorillonite composite (Cc-Mt) was synthesized for the single adsorption and co-adsorption of lead (Pb(II)) and a pharmaceutical emerging organic contaminant Atenolol (ATE). In single adsorption system, the maximum equilibrium capacity of Cc-Mt for Pb (II) and ATE were 139.78 mg g-1 and 86.86 mg g-1, respectively, but for montmorillonite just 98.69 mg g-1 and 69.68 mg g-1, for corncob biochar just 117.54 mg g-1 and 47.29 mg g-1. Meanwhile,co-adsorption properties of ATE and Pb(II) on Cc-Mt composite were performed and found that the influence of ATE on the adsorption of Pb(II) was greater than the effect of Pb(II) on that of ATE. Moreover, Multiwfn program based on quantum chemical calculation was used to quantitatively analyze electrostatic potential (ESP) distribution, average local ionization energy (ALIE) distribution and their minimum points on neutral ATE and protonated ATE (PATE) molecules to reveal the microscopic adsorption mechanism of Cc-Mt composite to ATE, the results showed that the amino N and amide oxygen atom were easier to provide lone pair of electrons, generating hydrogen bonds or strong electrostatic interactions with functional groups on the surface of Cc-Mt, meanwhile hydroxyl O atom was also a possible reaction site. For PATE molecules, only the oxygen atom of the amide group was the most likely reactive site.


Assuntos
Atenolol/análise , Bentonita/química , Carvão Vegetal/química , Chumbo/análise , Poluentes Químicos da Água/análise , Adsorção , Íons , Cinética , Modelos Teóricos , Propriedades de Superfície , Purificação da Água/métodos
3.
Chemosphere ; 240: 124922, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563718

RESUMO

This study examined the effects of soil heavy metals, macronutrients, texture and pH as well as plant species richness and composition on soil respiration, enzymatic activity, microbial biomass, metabolic quotient (qCO2) and arbuscular mycorrhizal fungi (AMF) at sites of historical Zn-Pb mining. The study was conducted both on a large scale (65 heaps scattered over the area of 750 km2) and on a small scale (25 plots along two 48 m transects extending from heaps to adjacent fallow fields). Total concentrations of metals exceeded 400 (Cd), 20,000 (Pb) and 80,000 (Zn) mg kg-1 at the most polluted sites. Although they decreased along the heap-fallow direction, they still remained above environmental standards in fallow soils. In contrast, some soluble metal forms increased with the increasing distance from heaps. Soil organic matter had the strongest positive effect on most microbial parameters. Total and/or available heavy metals exhibited significant negative effects on microbial biomass, enzymatic activity and AMF, and a positive effect on qCO2. Organic matter alleviated negative effects of heavy metals on microorganisms; they were not observed where the increase in the contamination was accompanied by the increase in organic matter content. Plant species richness affected positively enzymatic activity and mycorrhization level. Plant species composition possibly contributed to the formation of soil microbial communities, but its effect was entangled in that of heavy metals as plant communities changed along pollution gradients (from metal-tolerant grasslands dominated by Festuca ovina to calcareous grasslands and ruderal communities at less polluted sites).


Assuntos
Poluição Ambiental/análise , Festuca/microbiologia , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Biomassa , Cádmio/análise , Festuca/química , Substâncias Húmicas/análise , Chumbo/análise , Microbiota , Mineração , Micorrizas/crescimento & desenvolvimento , Microbiologia do Solo , Zinco/análise
4.
Chemosphere ; 240: 124938, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574444

RESUMO

Clearwater Mesa (James Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L-1. Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Minerais/análise , Compostos Orgânicos/análise , Oligoelementos/análise , Regiões Antárticas , Carbonatos/análise , Mudança Climática , Ecossistema , Camada de Gelo/química , Chumbo/análise , Trinidad e Tobago , Tempo (Meteorologia) , Zinco/análise
5.
Chemosphere ; 239: 124718, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31514008

RESUMO

Agaricus bisporus is the most commonly cultivated and consumed mushroom species. The aim of this study was to compare the profile of macro- and trace elements in A. bisporus fruit bodies produced commercially in 19 countries in 2018 and distributed worldwide (32 analyzed objects). Trace elements with unknown biological roles were also determined. The content of 36 elements (of 70 taken into account) revealed significant differences among the analyzed objects. Contents of Ca, K, Mg, Na and S varied in wide ranges of 425-2430, 12740-40940, 610-3240, 98-430 and 1030-2650 mg kg-1 dw, respectively. The fruit bodies were characterized by a generally similar content of trace elements with some clear exceptions. Rankings of the objects according to the decreased amount of macroelements, trace elements and all elements jointly, show that mushrooms are significantly diverse as regards the content of particular elements of the mentioned group. The analyzed fruit bodies displayed a relatively high content of Ca, Mo and Se, and a high K/Na ratio. Regardless of origin, A. bisporus did not constitute a source of significant levels of Al, Cd or rare earth elements. An increased level of As and Pb in mushrooms from several producers indicates a need for additional measures to reduce potential dietary exposures to these toxicants.


Assuntos
Agaricus/química , Inquéritos e Questionários , Oligoelementos/análise , Arsênico/análise , Saúde Global , Chumbo/análise
6.
Chemosphere ; 239: 124719, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726526

RESUMO

The goal of the present work was to evaluate the speciation of cadmium (Cd), copper (Cu) and lead (Pb) in sewage sludge (SL) amended soil and SL-biochar (BC) amended soil in a long-term field experiment. SL or SL with biochar (at the dose of 2.5%, 5.0% or 10%) were applied to the soil. The dose of SL in the soil was 11 tdw/ha. At the beginning of the study, after 12 and 18 months the distribution of Cd, Cu and Pb was determined between the following fractions: (1) water soluble, exchangeable and bound to carbonates (F1), (2) bound to Fe-Mn oxides (F2), (3) bound to organic matter (F3) and (4) bound to quartz, feldspars, etc. (F4). The soil, SL and biochar were characterized by different distribution of Pb, Cu and Cd. The highest mobility of Cd and Cu was observed in the control soil, while Pb in SL. Addition of SL to the soil caused the increased of the mobility index of Cu and Pb, increasing the risk associated with the presence of these metals in the mobile soil fraction (F1). However, the addition of biochar to SL before application to the soil modified the distribution of studied elements. The most mobile and bioavailable fractions (F1) were transferred to less bioavailable (F2, F3) and potentially immobile fractions (F4).


Assuntos
Cádmio/análise , Carvão Vegetal/química , Cobre/análise , Chumbo/análise , Esgotos/química , Poluentes do Solo/análise , Recuperação e Remediação Ambiental/métodos , Óxidos , Solo/química
7.
Sci Total Environ ; 702: 135017, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31734611

RESUMO

This study attempted to synthesize a novel ceramsite with excellent adsorption property compositing through the co-combustion of biomass and sewage sludge ash (CBSA), gasification of coal fly ash (GCFA) and sewage sludge (SS) to dispose wastewater contaminated by Pb (II). The optimum preparation conditions included a CBSA/SS/GCFA ratio of 70:18:12, preheating at 480 °C, and sintering at 1060 °C for 15 min. The basic and environmental characteristics of the novel ceramsite meet specific standards requirements. The removal rate could reach 99.9% under optimum conditions in a high-concentration solution, and the novel ceramsite could be reused 6 times and maintain in high remove rate. The adsorption mechanism was determined to be as follows: (1) Ceramsite features a mesoporous structure with an abundance of pores on which cationic exchange could occur. (2) Pb (II) enters the pores of the adsorbent and are attracted by anionic groups to deposit on the surface of ceramsite. (3) A large amount of Pb (II) bonds with SiO or AlOSiO to embed in the matrix frame of the adsorbent; the rest of the metal forms precipitates on the frame layer or [PO4].


Assuntos
Chumbo/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Biomassa , Cinza de Carvão , Chumbo/análise , Porosidade , Esgotos/química , Poluentes Químicos da Água/análise
8.
Food Chem ; 303: 125392, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446362

RESUMO

In this article, an easy and quick method based on microwave assisted acid digestion technique prior to quantification using inductively coupled plasma mass spectrometry for the analysis of heavy metals in cocoa beans, cocoa powder and chocolate was established and validated for arsenic (As), cadmium (Cd), lead (Pb), and antimony (Sb). Limit of quantification for all elements were product dependent and varies from 7.84 to 194.52 µg/kg. The recoveries of the heavy metals at 250 and 1000 µg/kg spiking levels were ranged between 96.27-108.75%, 90.43-101.97% and 89.72-106.26% for cocoa beans, cocoa powder, and chocolate, respectively. Relative standard deviation values obtained were all below 20% and the expanded uncertainty measurements for the elements were less than 25%. The analysis of real samples found that the concentration level is far from the national alarming level except for cadmium in cocoa beans.


Assuntos
Cacau/química , Fracionamento Químico/métodos , Espectrometria de Massas/métodos , Metais Pesados/análise , Micro-Ondas , Sementes/química , Antimônio/análise , Arsênico/análise , Cádmio/análise , Chocolate/análise , Chumbo/análise
9.
Food Chem ; 303: 125396, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446365

RESUMO

This study describes the determination of lead at trace levels by slotted quartz tube flame atomic absorption spectrophotometry (SQT-FAAS) after preconcentration by the help of stearic acid coated magnetic nanoparticle (SAC-MNPs) based sonication assisted dispersive solid phase extraction (SA-DSPE). SAC-MNPs were used due to their easy separation advantages by the application of external magnetic field. All extraction parameters were optimized by response surface methodology based experimental design. The experimented data was evaluated by the analysis of variance. Under the optimum conditions, about 31 folds enhancement in detection power was obtained over the conventional FAAS. The recovery results obtained for samples spiked at 60 and 120 ng mL-1 were 106.6 and 102.6%, respectively, validating the method as accurate and applicable to the red pepper matrix. The percent relative standard deviations of the results were under 5.0% even at low concentrations that established high precision for replicate extractions and instrumental readings.


Assuntos
Capsicum/química , Chumbo/análise , Chumbo/isolamento & purificação , Microextração em Fase Líquida/métodos , Magnetismo/métodos , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Contaminação de Alimentos/análise , Frutas/química , Magnetismo/instrumentação , Nanopartículas de Magnetita/química , Quartzo/química , Sensibilidade e Especificidade , Sonicação , Ácidos Esteáricos/química
10.
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
11.
Food Chem ; 303: 125374, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473457

RESUMO

The application of a novel Pb2+ selective sensor based on the ionic imprinted polymer in determining trace levels of lead in natural water and in fruit juice was investigated using differential pulse voltammetry (DPV). The new and selective magnetic ion-imprinted polymer (Fe3O4@SiO2@IIP) was synthesized using 2-(2-aminophenyl)-1H-benzimidazole and 4-vinyl pyridine as a ligand and functional monomer, respectively. The new polymer was utilized for modifying a GCE to generate a new electrochemical sensor. Box-Behnken design (BBD) was utilized for optimizing the parameters influencing the peak current. Extremely suitable voltammetric performance was demonstrated for the electrochemical detection of lead with a low detection limit (0.05 ng mL-1), over a wide linear concentration range (0.1-80 ng mL-1). This modified electrode as a novel sensor was utilized for determining Pb(II) ions in natural water and in fruit juice with very reasonable outcomes.


Assuntos
Técnicas Eletroquímicas/métodos , Chumbo/análise , Polímeros/química , Cátions Bivalentes , Eletrodos , Compostos de Ferro/química , Chumbo/química , Limite de Detecção , Magnetismo , Dióxido de Silício/química
12.
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
13.
Chemosphere ; 238: 124541, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31422313

RESUMO

Quantifying variation of metals in urban soils is crucial for efficient environmental and public health management. Prior to the interferences of human activities, regional topsoil geochemical distributions were generally primarily controlled by the underlying parent materials (PMs). With the rapid urbanisation, urban topsoil geochemical distributions have been modified with different levels. Three metals, aluminium (Al), calcium (Ca) and lead (Pb), were chosen to investigate the different levels of geogenic and anthropogenic controls in urban topsoil of Greater London Authority (GLA) area. These three metal elements clearly demonstrated the different spatial distribution affected by human activities using analysis of variance (ANOVA) and GIS-based spatial analysis. The high values of Al were in the clay which is located in the north and south GLA area; Pb accumulated in built-up areas and near traffic roads, which was likely associated with leaded paints and leaded petrol, respectively; the high Ca concentrations were in the Chalk bedrock of the southern GLA area and historical deconstruction and reconstruction sites in the city centre. Based on spatial interpolation and hot spot analysis (local Moran's I), this study reveals the different levels of geogenic and anthropogenic controls on different chemicals in urban soils: while the spatial distribution of Pb, which is more easily affected by human activities, can be significantly changed, the inert element Al may still be able to maintain its natural spatial distribution even in the heavily urbanized GLA area, and Ca demonstrates the mixed spatial distribution affected by both natural factors and human activities.


Assuntos
Alumínio/análise , Cálcio/análise , Monitoramento Ambiental , Chumbo/análise , Poluentes do Solo/análise , Solo/química , Análise Espacial , Cidades , Humanos , Londres
14.
Sci Total Environ ; 699: 134330, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31522043

RESUMO

Rice is one of the principal staple foods, essential for safeguarding the global food and nutritional security, but due to different natural and anthropogenic sources, it also acts as one of the biggest reservoirs of potentially toxic metal(loids) like As, Hg, Se, Pb and Cd. This review summarizes mobilization, translocation and speciation mechanism of these metal(loids) in soil-plant continuum as well as available cost-effective remediation measures and future research needs to eliminate the long-term risk to human health. High concentrations of these elements not only cause toxicity problems in plants, but also in animals that consume them and gradual deposition of these elements leads to the risk of bioaccumulation. The extensive occurrence of contaminated rice grains globally poses substantial public health risk and merits immediate action. People living in hotspots of contamination are exposed to higher health risks, however, rice import/export among different countries make the problem of global concern. Accumulation of As, Hg, Se, Pb and Cd in rice grains can be reduced by reducing their bioavailability, and controlling their uptake by rice plants. The contaminated soils can be reclaimed by phytoremediation, bioremediation, chemical amendments and mechanical measures; however these methods are either too expensive and/or too slow. Integration of innovative agronomic practices like crop establishment methods and improved irrigation and nutrient management practices are important steps to help mitigate the accumulation in soil as well as plant parts. Adoption of transgenic techniques for development of rice cultivars with low accumulation in edible plant parts could be a realistic option that would permit rice cultivation in soils with high bioavailability of these metal(loid)s.


Assuntos
Exposição Dietética/estatística & dados numéricos , Monitoramento Ambiental , Metaloides/análise , Poluentes do Solo/análise , Agricultura , Arsênico/análise , Cádmio/análise , Humanos , Chumbo/análise , Mercúrio/análise , Oryza , Selênio/análise , Solo
15.
Environ Health Prev Med ; 24(1): 72, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31805868

RESUMO

BACKGROUND: Lead is a toxic metal abundant in the environment. Consumption of food contaminated at low levels of lead, especially by small children and pregnant women, raises a health concern. METHODS: Duplicated food portions and drinking water were collected over 3 days from 88 children and 87 pregnant women in Shimotsuke, Tochigi, Japan. Participants were recruited in this study between January 2014 and October 2015. Dust was also collected from their homes. Lead concentrations were measured and consequent oral lead exposure levels were estimated for this population at high risk to environmental toxicants. Lead concentrations of peripheral and cord blood, taken from children and pregnant women, and were also analyzed. RESULTS: Lead concentrations in food, drinking water, and house dust were low in general. Oral lead exposure to lead was higher for children (Mean ± SEM; 5.21 ± 0.30 µg/kg BW/week) than in pregnant women (1.47 ± 0.13 µg/kg BW/week). Food and house dust were main sources of lead contamination, but the contribution of house dust widely varied. Means ± SEM of peripheral and cord blood lead concentrations were 0.69 ± 0.04 µg/dL and 0.54 ± 0.05 µg/dL, respectively for pregnant women and 1.30 ± 0.07 µg/dL (peripheral only) in children. We detect no correlation between smoking situations and blood lead concentration in pregnant women. CONCLUSION: We conclude that oral lead exposure levels for Japanese children and pregnant women were generally low, with higher concentrations and exposure for children than for pregnant women. More efforts are necessary to clarify the sources of lead contamination and reduce lead exposure of the population at high risk even in Japan.


Assuntos
Exposição Dietética/análise , Poeira/análise , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Chumbo/análise , Adulto , Pré-Escolar , Água Potável/análise , Poluentes Ambientais/sangue , Feminino , Sangue Fetal/química , Humanos , Lactente , Japão , Chumbo/sangue , Masculino , Gravidez , Adulto Jovem
16.
Chem Commun (Camb) ; 56(2): 289-292, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31808471

RESUMO

A novel biosensor for the rapid detection of lead ions employing the optical properties of AuNPs, a lead-specific aptamer and a cationic peptide has been demonstrated. The limit of detection of the biosensor was 98.7 pM, the lowest so far obtained using colorimetry.


Assuntos
Aptâmeros de Nucleotídeos/química , Colorimetria/métodos , Chumbo/análise , Nanopartículas Metálicas/química , Peptídeos/química , Técnicas Biossensoriais/métodos , Cor , DNA/química , Ouro/química , Limite de Detecção , Ressonância de Plasmônio de Superfície/métodos
17.
Sci Total Environ ; 694: 133693, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31756810

RESUMO

Designer biochars can be used to remediate organic and inorganic contaminant polluted soils. Here, a waste timber biochar (BC), a coconut shell activated biochar (aBC) and a wood shrub iron enriched designer biochar (Fe-BC) were investigated. Per- and polyfluorinated alkyl substances (PFAS) contaminated soils with different total organic carbon (TOC) contents (1.6 and 34.2%) were amended with six doses of BC and aBC. Two shooting range soils (TOC 5.2 and 10.2%) contaminated with heavy metals (mainly Pb and Sb) were amended with four doses of BC and Fe-BC. An amendment of 20% BC reduced the PFOS leachate concentration by 86% for the low TOC soil but was not effective for the high TOC soil. An amendment of 1% aBC reduced PFOS leachate concentrations by over >96% for both soils. For the low TOC shooting range soil, a 20% amendment of BC reduced Pb and Sb leaching by 61% and 12%, respectively. An amendment of 20% Fe-BC to soil with low TOC reduced Pb and Sb leaching by 99% and 40%, respectively. The need for "designer" biochars using processes such as iron enrichment or activation should be considered depending on the TOC of the soil, the type of contaminants and remediation goals.


Assuntos
Recuperação e Remediação Ambiental/métodos , Fluorcarbonetos/química , Metais Pesados/química , Poluentes do Solo/química , Antimônio/análise , Antimônio/química , Carvão Vegetal/química , Fluorcarbonetos/análise , Chumbo/análise , Chumbo/química , Metais Pesados/análise , Solo
18.
Sci Total Environ ; 694: 133489, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31756826

RESUMO

Environmental lead (Pb) contamination is a persistent public health issue that prominently impacts communities across the United States. Multimedia Pb exposure assessments are utilized to provide a holistic evaluation of Pb exposure and inform the development of programs and regulations that are protective of human health. To conduct multimedia exposure assessments, robust, media-specific environmental Pb concentration data are necessary. To support this effort, systematic review and meta-analysis methods were used to conduct a comprehensive synthesis of research measuring Pb in multiple environmental media (soil, dust, water, food, and air) over a 20-year period within the United States. The breadth of the resulting database allowed for the evaluation of sample characteristics that can serve as indicators of environmental Pb contamination. Random effects models run on literature and national survey datasets generated overall mean estimates of Pb concentrations that can be used for multimedia Pb exposure modeling for general and high-exposure-risk populations. Results from our study highlighted several important trends: 1) The mean estimate of Pb in residential soils is three times higher for urbanized areas than non-urbanized areas; 2) The mean estimate of Pb in produce reported in the literature is approximately three orders of magnitude greater than commercially-sourced raw produce monitored in national surveys; 3) The mean estimate of Pb in soils from shooting ranges is two times greater than non-residential Pb contaminated Superfund sites reported in the literature; 4) Research reporting environmental Pb concentrations for school and daycare sites is very limited; 5) Inconsistent sample collection and reporting of results limited synthesis efforts; and 6) The U.S. EPA's Air Quality System was the most robust, publicly available national survey resource. Results from these analyses will inform future multimedia Pb exposure assessments and be useful in prioritizing future research and program development.


Assuntos
Poluentes Ambientais/análise , Poluição Ambiental/estatística & dados numéricos , Chumbo/análise , Estados Unidos
19.
Bull Environ Contam Toxicol ; 103(6): 848-853, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31667530

RESUMO

In the present study, biochar particles (BPs) produced by the co-pyrolysis of sewage sludge and corncobs at temperatures of 300, 500, and 700°C were characterized. The Pb2+ adsorption properties and the heavy metal leaching toxicity rates of the BPs were investigated. It was found that the adsorption kinetics of the Pb2+ can be accurately described by a pseudo-second-order model, and the equilibrium adsorption data were well represented by both the Langmuir and the Freundilich Equations. The toxicity characteristic leaching procedure (TCLP) results indicated that the leaching concentrations of all the heavy metals were below the set limit of China's national standard (Identification Standard for Hazardous Waste Extraction Toxicity Identification, China National Standard, GB 5085.3-2007). The results of this study can successfully provide scientific support for future corncob treatment and sludge pollution control.


Assuntos
Carvão Vegetal/química , Chumbo/análise , Esgotos/química , Poluentes Químicos da Água/análise , Zea mays/química , Adsorção , China , Resíduos Perigosos/análise , Temperatura Alta , Cinética , Modelos Teóricos , Águas Residuárias/química , Purificação da Água/métodos
20.
Environ Monit Assess ; 191(12): 751, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31732816

RESUMO

Plant-based materials are promising adsorbents for treating liquid effluents. This study describes the kinetic and equilibrium parameters that best represent the copper(II) and lead(II) removal process by Eichhornia crassipes (Aguapé) dry biomass from aqueous solution, using a batch adsorption system. The plants were washed, dried, and reduced to small particles. The adsorption kinetics were assessed by varying the metal concentrations in 5, 10, and 20 mg L-1 and a control treatment (without metals) with a mixture contact time of between 5 and 720 min. Equilibrium data were fitted to the Langmuir and Freundlich models. Kinetic assay revealed fast adsorption: kinetic equilibrium was attained within 2 h with a removal efficiency of ~ 60%. The results demonstrated a fast recovery cycle of metals using the biosorbent. The biomass of E. crassipes is low cost with potential for use as a biosorbent to remove metals from solutions.


Assuntos
Biodegradação Ambiental , Cobre/análise , Eichhornia/metabolismo , Chumbo/análise , Poluentes Químicos da Água/análise , Adsorção , Biomassa , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Cinética , Água/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA