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1.
BMC Complement Med Ther ; 22(1): 4, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983490

RESUMO

BACKGROUND: Though Lippia javanica (Burm.f.) Spreng antioxidant activity has been demonstrated, its effect in protecting the brain from lead (Pb)-induced oxidative damage is unknown. This study investigated the effect of L. javanica against Pb-induced oxidative stress, inflammation, apoptosis and acetylcholinesterase activity in rat's brain. METHODS: L. javanica herbal tea infusion was prepared, its phytochemical constituent was revealed by liquid chromatography-Mass spectrometer (LC-MS) and was administered simultaneously with Pb. Four groups of male Wistar rats (n = 5/group) were used: control received distilled water; Pb-acetate group received 50 mg Pb/ Kg bodyweight (bw), treatment group received 50 mg Pb/ Kg Pb-acetate + 5 ml/kg bw L. javanica and L. javanica group received 5 ml/Kg bw of L. javanica tea infusion only. After 6 weeks of treatment, oxidative status, acetylcholinesterase activity, inflammation and apoptosis was assessed in brain tissue which was also histologically examined. RESULTS: Mean brain and heart weight was reduced (p < 0.05) while liver and spleen weights were increased (p < 0.05) in Pb exposed animals but were prevented by L. juvanica treatment. Treatment with L. javanica increased (p < 0.05) overall brain antioxidant status (glutathione and superoxide dismutase activities) and reduced lipid peroxidation (p < 0.05) compared to the Pb exposed animals. Pro-inflammatory cytokine tumour necrotic factor-alpha, pro-apoptosis Bax protein and anticholinesterase activity were reduced (p < 0.05) in Pb-L. javanica treated animals compared to the Pb exposed group. Histological examination confirmed neuroprotective effects of L. javanica as evidenced by reduced apoptosis/necrosis and inflammation-induced vacuolization and oedema in the hippocampus. The L. javanica treatment alone had no detrimental effects to the rats. LC-MS analysis revealed L. javanica to be rich in phenolics. CONCLUSIONS: This study demonstrated that L. javanica, rich in phenolics was effective in reducing Pb-induced brain oxidative stress, inflammation, apoptosis, acetylcholinesterase activity and neuronal damage.


Assuntos
Encéfalo/metabolismo , Chumbo/efeitos adversos , Lippia/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Chás de Ervas , Animais , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar
2.
Matern Child Health J ; 26(1): 185-192, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35020085

RESUMO

OBJECTIVES: Lead exposure has devastating neurologic consequences for children and may begin in utero. The American College of Obstetricians and Gynecologists recommends prenatal lead screening using a risk factor-based approach rather than universal blood testing. The clinical utility of this approach has not been studied. We evaluated a risk-factor based questionnaire to detect elevated blood lead levels in pregnancy. METHODS: We performed a secondary analysis of a cohort of parturients enrolled to evaluate the association of lead with hypertensive disorders of pregnancy. We included participants in this analysis if they had a singleton pregnancy ≥ 34 weeks' gestation with blood lead levels recorded. Participants completed a lead risk factor survey modified for pregnancy. We defined elevated blood lead as ≥ 2 µg/dL, as this was the clinically reportable level. RESULTS: Of 102 participants enrolled in the cohort, 92 had blood lead measured as part of the study. The vast majority (78%) had 1 or more risk factor for elevated lead using the questionnaire yet none had clinical blood lead testing during routine visits. Only two participants (2.2%) had elevated blood lead levels. The questionnaire had high sensitivity but poor specificity for predicting detectable lead levels (sensitivity 100%, specificity 22%). CONCLUSIONS FOR PRACTICE: Prenatal risk-factor based lead screening appears underutilized in practice and does not adequately discriminate between those with and without elevated blood levels. Given the complexity of the risk factor-based approach and underutilization, the benefit and cost-effectiveness of universal lead testing should be further explored.


Assuntos
Hipertensão , Chumbo , Criança , Feminino , Idade Gestacional , Humanos , Programas de Rastreamento , Gravidez , Fatores de Risco
3.
Huan Jing Ke Xue ; 43(1): 472-480, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989532

RESUMO

The bioavailability of heavy metals in soil and the physiological activities of rice determine the accumulation of heavy metals in brown rice. In this study, a field experiment was conducted in a rice paddy in which the total amount of Cd in the soil did not exceed the national standard, whereas the Cd in rice grains was at risk of overreaching in the suburbs of Guangzhou city. The bioavailability of heavy metals in the soil and the physiological barrier of rice were taken as the starting point. The early and late rice yield, brown rice heavy metal content, Cd and Pb enrichment coefficient, total soil heavy metals, soil physical and chemical properties, and soil Cd and Pb species distribution were investigated under the Si-rich amendment (JD), Ca-Mg amendment (YY), Si-rich amendment+flooding irrigation (JD+YS), and Ca-Mg amendment+flooding irrigation (YY+YS) treatments. The results showed that:① the total ω(Cd) in the soil was only 0.13 mg·kg-1 in the CK treatment. However, the average ω(Cd) in the grain of early rice reached up to 0.19 mg·kg-1. The early rice varieties (hybrid rice) had a more vital ability to accumulate Cd and total As in brown rice than that in late rice varieties (conventional rice) but a lower capacity for Pb accumulation. ② JD and YY application alone had no noticeable inhibitory effect on the accumulation of Cd and Pb in brown rice; however, JD+YS and YY+YS treatments significantly inhibited the accumulation of Cd and Pb in brown rice in both early and late rice, especially in the JD+YS treatment, which decreased the Cd and Pb accumulation by 65.8% and 68% for early rice and by 71.43% and 49.15% for late rice, respectively. The primary mechanism of JD+YS was to increase soil pH and maintain a low redox potential to promote soil Cd and Pb to be transformed from acid-soluble to a reduced state and residue state, thus decreasing Cd and Pb to migrate from the soil to the rice. At the same time, it effectively suppressed the absorption and transportation of Cd and Pb by early and late rice via the physiological barrier effect of Si nutrition and the competition for transportation channels between calcium and magnesium ions and cadmium and inhibited the accumulation of Cd and Pb in the brown rice of early and late rice. These results provide a theoretical basis for the exploration and application of the control technologies in the brown rice Cd and Pb resistance and have important practical significance for guiding the safe production in the rice-growing area in South China.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Chumbo , Solo , Poluentes do Solo/análise , Água , Abastecimento de Água
4.
Huan Jing Ke Xue ; 43(1): 481-489, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989533

RESUMO

In recent years, dust pollution has occurred frequently in spring and haze or fog in autumn and winter. The inhalable particulate matters in the atmosphere, especially PM2.5, loaded in heavy metals such as cadmium, lead, and arsenic, are easily taken up by leafy vegetables and accumulate in the edible parts. It is not clear whether the accumulation of heavy metals in the edible parts of leafy vegetables in greenhouses is also affected by atmospheric deposition. Therefore, a field experiment was conducted to explore characteristics and health risk assessment of cadmium, lead, and arsenic accumulation in leafy vegetables planted in a greenhouse using six types of common leafy vegetables (spinach, leaf lettuce, lettuce, pakchoi, Chrysanthemum coronarium, and fennel) in the Beijing-Tianjin-Hebei region. The results showed that C. coronarium, pakchoi, and spinach are the leafy vegetables with a low accumulation of Cd, Pb, and As, respectively. Fennel is the leafy vegetable with a low accumulation of Cd and Pb. In the greenhouse, Pb concentrations in PM2.5 were 42.6 and 8.4 times of Cd and As, respectively. Moreover, PM2.5-Pb contributed on average 36.5% to the edible parts of six kinds of leafy vegetables, which indicated that the Cd, Pb, and As accumulated in leafy vegetables were mainly derived from the soil. Meanwhile, the concentrations of Cd, Pb, and As in the edible parts of vegetables did not exceed the safety limitations of three heavy metals (GB 2762-2017), and Pb accumulation in leafy vegetables does not pose a health risk to humans. However, Cd in the leafy vegetables could threaten the health of adults and children, except for the intake of fennel. Conversely, As in the C. coronarium could threaten the health of adults and children.


Assuntos
Arsênio , Metais Pesados , Poluentes do Solo , Adulto , Cádmio/análise , Criança , Humanos , Chumbo , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Verduras
5.
J Hazard Mater ; 423(Pt A): 126975, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34788938

RESUMO

Pb(II) contamination imposes serious threats to human health and the environment. Biological reduction of Pb(II) to metallic Pb is an attractive method for the remediation of Pb(II)-contaminated water and sediments. In this study, Pb(II)-reducing microorganisms were isolated by the dilution-to-extinction (DTE) and streak-plate methods. As a result, Delftia acidovorans, Azonexus caeni, and Comamonas testosteroni were successfully isolated. At a high lead concentration (10 mg-Pb(II)/L), each of the isolated D. acidovorans strain Pb11 and A. caeni strain Pb2 cultures showed successful utilization of Pb(II), resulting in a 5.15- and 8.14-fold growth in 3 days, respectively. Pb(II) reduction to metallic Pb by D. acidovorans strain Pb11 and A. caeni strain Pb2 was confirmed using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) was coupled with X-ray photoelectron spectroscopy (XPS). This strategic analysis was necessary to confirm the formation of metallic Pb separately from lead phosphate precipitates which are inevitable in the biological Pb(II) removal experiments. Among the 3 isolated microbes, C. testosteroni strain Pb3 did not leave immobile and detectable Pb solids in SEM-EDS analyses. D. acidovorans and A. caeni are recommended for engineered remediation of Pb(II)-contaminated wastewater and sediments.


Assuntos
Comamonas testosteroni , Chumbo , Adsorção , Bactérias , Humanos , Chumbo/análise , Espectrometria por Raios X , Águas Residuárias
6.
Waste Manag ; 137: 319-328, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34837743

RESUMO

The traditional sodium desulfurization process for waste lead-acid batteries is beneficial to the environment; however, it is limited by poor economic viability as the cost of desulfurizer is much higher than the value of desulfurization by-products. This study proposes a new closed-loop pre-desulfurization process for lead paste, which consumes only lime as the indirect desulfurizer, produces sodium sulfate as a by-product, and regenerates sodium hydroxide as the direct desulfurizer. The concentration of prepared sodium hydroxide reached 2.57 mol/L when the reaction was conducted at room temperature for 2.0 h, with a sodium oxalate: calcium oxide molar ratio of 1:1.3, a CaO: water mass ratio of 1:6, and magnetic stirring at 600 rpm. Cost estimation and economic analyses were also conducted. The cost of lead paste generated by this new pre-desulfurization process was 37.62 dollars/ton lower than traditional high-temperature smelting, and 44.42 dollars/ton lower than direct sodium pre-desulfurization. Thus, this process provides a practical and feasible clean recycling method for waste lead-acid batteries with significant environmental and economic benefits.


Assuntos
Chumbo , Reciclagem , Fontes de Energia Elétrica , Hidróxido de Sódio , Água
7.
Bioresour Technol ; 344(Pt B): 126269, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34740798

RESUMO

It is crucial to develop a new characterization method to provide insight into the complex adsorption mechanism of crop residue-derived char. This study established a novel 3D in-situ visualization method for qualitative and semi-quantitative characterizing Pb (II) adsorption profiles in crop residue-derived char particles. First, coconut shell activated carbon, rice husk biochar, and wheat biochar after Pb (II) adsorption was used for X-ray micro-CT imaging. Then, the K-means clustering algorithm was developed for segmenting the volume image of samples, and the optimized segmentation thresholds for the 3 samples were 6000HU, 7000HU, and 1300HU, respectively. The rendered images for qualitative illustrating the adsorption profile of Pb (II) were presented. Finally, based on the derived quantitative formula, the Pb (II) distribution in the biochar particle was presented for the first time. This method provided a new perspective and methodology for analysis and simulations of the adsorption behavior of heavy metals onto chars.


Assuntos
Metais Pesados , Oryza , Adsorção , Carvão Vegetal , Chumbo , Microtomografia por Raio-X
8.
Chemosphere ; 287(Pt 3): 132279, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34563768

RESUMO

Red mud modified by chitosan (RM/CS) was utilized as an adsorbent to effectively remove Pb(II) from aqueous solution. The surface area of RM/CS was found to significantly increase by more than 50% compared to that of original red mud. Different factors that affected the Pb(II) removal on this material, such as initial Pb(II) concentration, pH, and contact time, were investigated. The pseudo-first-order, pseudo-second-order, and intra-diffusion models were used to fit the experimental data to investigate the Pb(II)'s removal kinetics. The Pb(II) removal followed the intra-diffusion model. Additionally, the non-zero C value obtained from this model indicates that the removal was controlled by many different mechanisms. We also found that the interaction of Pb(II) and carbonate group on the material's surface played a primary role once the adsorption equilibrium was reached. Finally, the maximum adsorptive capacity was found to be about 209 mg/g. This obtained value is higher than those obtained for some other materials. Therefore, the present RM/CS should be a potential material for removing Pb(II) from aqueous solution.


Assuntos
Quitosana , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Chumbo
9.
Sci Total Environ ; 806(Pt 1): 150088, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34563906

RESUMO

Electrochemical oxidation (EO) based on hydroxyl radicals (·OH) generated on lead dioxide has become a typical advanced oxidation process (AOP). Titanium-based lead dioxide electrodes (PbO2/Ti) play an increasingly important role in EO. To further improve the efficiency, the structure and properties of the lead dioxide active surface layer can be modified by doping transition metals, rare earth metals, nonmetals, etc. Here, we compare the common preparation methods of lead dioxide. The EO performance of lead dioxide in wastewater containing dyes, pesticides, drugs, landfill leachate, coal, petrochemicals, etc., is discussed along with their suitable operating conditions. Finally, the factors influencing the contaminant removal kinetics on lead dioxide are systematically analysed.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Eletrodos , Chumbo , Oxirredução , Óxidos , Titânio , Poluentes Químicos da Água/análise
10.
Bioresour Technol ; 343: 126046, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34592449

RESUMO

Ca-based magnetic bamboo-derived hydrochar described as Ca-MBHC was synthesized by one-pot pyrolysis, and was applied to remediation of lead (Pb) and tetracycline (TC) polluted water. Characterizations not only attested the loading of CaCO3 and Fe0 onto the hydrochar, but also demonstrated the magnetism of Ca-MBHC. Adsorption kinetic experiments showed that the Ca-MBHC could eliminate Pb(II) and TC during a wide range of pH, and appeared rapid uptake equilibrium within 240 and 60 min for Pb(II) and TC, severally. Adsorption isotherm experiments showed that the Ca-MBHC possessed highest adsorption of 475.58 mg/g concerning Pb(II), and heterogeneous uptake of 142.44 mg/g for TC. Furthermore, the Ca-MBHC could achieve Pb(II) binding owing to complexation, reduction, ion exchange and electrostatic attraction, whereas the TC uptake might be related to π-π stacking reciprocities, pore filling and hydrogen bonding. Overall, the Ca-MBHC could be viewed as an excellent adsorbent for scavenging Pb(II) and tetracycline from water.


Assuntos
Pirólise , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Chumbo , Fenômenos Magnéticos , Tetraciclina , Água , Poluentes Químicos da Água/análise
11.
Chemosphere ; 287(Pt 4): 132457, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34610373

RESUMO

Lead (Pb) is the most widely used anode in zinc (Zn) electrowinning and other metallurgical industries. The resource loss and environmental pollution caused by Pb anode corrosion are urgent problems to be solved. A γ-MnO2 precoated anode was prepared successfully to reduce the Pb-containing pollutant. The size effects with its controllable preparation on an industrial scale were studied. Severe nonuniform distribution of γ-MnO2 film was observed with curbing the reduction of anode slime only 68%, when anode size increased from lab to industry. Nonuniform rate (R) and average thickness (d) were found to be the key indicators to determine the film structure distribution and their performance differences, which were random and difficult to be controlled in scale-up size. However, a controllable industrial γ-MnO2 precoated anodes (IMPA) fabricated through optimized current density (J0) and electrodeposition time (t) in our developed film-forming system. Then, the long-term performances of two IMPA with different indicators (IMPA-1: R = 34%, d = 108 µm, IMPA-2: R = 23%, d = 55 µm) were compared with the industrial typical Pb-based anode (ITPA). Of the three different anodes, the optimized IMPA-2 displayed the best performance. Within 24 d of electrowinning cycle, the corrosion inhibition effect and the anode slime reduction rate for IMPA-2 improved by 56% and 30% than IMPA-1, and improved by 100% and 91% than ITPA. Furthermore, the mechanism analysis of size effect change showed that R of IMPA was contributed to the local gas holdup distribution along the anode. Controlled size effect of uniform oxide film will have a future application prospect for the sustainability of industry, which provides an important cleaner production of Zn electrowinning and related hydrometallurgy industries.


Assuntos
Poluentes Ambientais , Zinco , Eletrodos , Chumbo , Compostos de Manganês , Metalurgia , Óxidos
12.
Bioresour Technol ; 343: 126081, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34610424

RESUMO

The adsorption performance and mechanisms of Pb2+ and Cd2+ in wastewater using MgO modified biochar derived from crofton weed (MBCW600) are investigated. The Pb2+ and Cd2+ adsorption capacities of MBCW600 by the Hill model reach 384.08 mg/g and 207.02 mg/g, respectively, which is larger than that of original biochar. Pb2+ could be more easily captured by MBCW600 compared to Cd2+ in the multimetal system. Mg2+ contributes to Pb2+ and Cd2+ adsorption among coexisting cations. The exhausted MBCW600 could be well regenerated by simple method after use. The adsorption mechanism study indicates that Pb2+ and Cd2+ removal are primary contributed to mineral precipitation and ion exchange. The effective treatment volumes of Pb2+ and Cd2+ wastewater achieve 3050 mL and 2150 mL in the fixed-bed column experiment, respectively. Therefore, MBCW600 presents remarkable adsorption capability, excellent recoverability and large throughput, which shows the potential application in future treatment of wastewater containing heavy metal.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Adsorção , Cádmio , Carvão Vegetal , Chumbo , Óxido de Magnésio , Poluentes Químicos da Água/análise
13.
Environ Pollut ; 292(Pt A): 118339, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34637824

RESUMO

Non-exhaust emissions (e.g., particles from brake pads, asphalt, curb, road paint, tire) are important sources of potentially toxic elements (PTEs) pollution in urban environments and are potential causes of PTEs pollution in road dust. We present the PTEs concentrations (Cr, Ni, Cu, Zn, As, Cd, Sn, Sb, Pb) of non-exhaust emission sources and pollution degree of PTEs. Isotopic signatures of Cu, Zn, and Pb were also analyzed to distinguish these sources. Among PTEs, the Cu concentration in all brake pads was significantly high and brake pads from Korea showed remarkably high Sb concentrations. Asphalt had a higher Pb concentration than other non-exhaust emission sources. Mean of δ65CuAE647, δ66ZnIRMM3702, and 206Pb/207Pb values of non-exhaust emission sources in this study ranged from -0.49‰ to +0.19‰, -0.24‰ to +0.16‰, and 1.1535 to 1.4471, respectively. Non-exhaust emission sources could be discriminated by plotting the concentration and isotopic composition of Cu. Cu isotopic compositions (δ65CuAE647) were clearly distinguished between brake pads including domestic and imported products and tires. Zn isotope values (δ66ZnIRMM3702) of brake pads, tires, and asphalt overlapped, but discriminated from road paint and curb. Our results indicate that the combination of Cu and Zn isotopic signatures can distinguish various non-exhaust traffic emissions, especially brake pads and tires.


Assuntos
Chumbo , Metais Pesados , Poeira/análise , Monitoramento Ambiental , Poluição Ambiental , Isótopos , Metais Pesados/análise , Medição de Risco , Zinco
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120460, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34637985

RESUMO

The feasibility analysis of fluorescence hyperspectral imaging technology was studied for the detection of lead content in lettuce leaves. Further, Monte Carlo optimized wavelet transform stacked auto-encoders (WT-MC-SAE) was proposed for dimensionality reduction and depth feature extraction of fluorescence spectral data. The fluorescence hyperspectral images of 2800 lettuce leaf samples were selected and the whole lettuce leaf was used as the region of interest (ROI) to extract the fluorescence spectrum. Five different pre-processing algorithms were used to pre-process the original ROI spectral data including standard normalized variable (SNV), first derivative (1st Der), second derivative (2ndDer), third derivative (3rd Der) and fourth derivative (4th Der). Moreover, wavelet transform stacked auto-encoders (WT-SAE) and WT-MC-SAE were used for data dimensionality reduction, and support vector machine regression (SVR) was used for modeling analysis. Among them, 4th Der tends to be the most useful fluorescence spectral data for Pb content detection at 0.067 âˆ¼ 1.400 mg/kg in lettuce leaves, with Rc2 of 0.9802, RMSEC of 0.02321 mg/kg, Rp2 of 0.9467, RMSEP of 0.04017 mg/kg and RPD of 3.273, and model scale (the number of nodes in the input layer, hidden layer and output layer) was 407-314-286-121-76 under the fifth level of wavelet decomposition. Further studies showed that WT-MC-SAE realizes the depth feature extraction of the fluorescence spectrum, and it is of great significance to use fluorescence hyperspectral imaging to realize the quantitative detection of lead in lettuce leaves.


Assuntos
Aprendizado Profundo , Metais Pesados , Algoritmos , Chumbo , Análise dos Mínimos Quadrados , Alface , Folhas de Planta , Tecnologia
15.
Anal Chim Acta ; 1189: 339214, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815040

RESUMO

Bioaccessibility (the amount of a contaminant extracted by the gastrointestinal fluids during digestion) is often incorporated in the assessment of contaminated soils and foods. Current methods, including those published by the United States Environmental Protection Agency (US EPA) and United States Pharmacopoeia (USP), use a batch method of analysis which requires hours of extraction prior to instrumental analysis with inductively coupled plasma mass spectrometry (ICPMS). The continuous on-line leaching method (COLM) uses a more direct method of analysis as extracts are sent directly to the ICPMS instrument, which can reduce extraction time and give real-time elution kinetics. For this study, four reference soils (NIST 2710, NIST 2710a, NIST 2711a, and BGS 102) that are typically used with bioaccessibility methods were extracted using the COLM and US EPA and USP gastrointestinal fluids. With the transient time-resolved data from the COLM, differential elution indicating multiple Pb sources was observed in NIST 2710a, NIST 2711a, and BGS 102. Two methods for calculating the Pb isotope ratios to identify these sources included a point-by-point ratio average method and a more precise regression slope method. There was no statistically significant difference between the ratios obtained by these methods of calculation. Furthermore, NIST 2710a and NIST 2711a did not have any statistically significant difference between the Pb isotope ratios of two observed sources. BGS 102 had a significantly different secondary source of Pb, which was identified to be from Pb historically added to gasoline. Investigation into the regions these soil reference materials were sourced from supported this finding as BGS 102 comes from a more densely populated, industrialized area where soil contamination with Pb from gasoline is likely to be more prevalent. This type of bioaccessibility investigation is only possible with the COLM as it gives real time elution information. Incorporation of the COLM into future bioaccessibility studies (and inclusion of other elements for isotopic analysis, like Sr) will lead to more thorough and comprehensive bioaccessibility studies in the future.


Assuntos
Poluentes do Solo , Solo , Chumbo , Espectrometria de Massas , Poluentes do Solo/análise , Análise Espectral
16.
Chemosphere ; 287(Pt 2): 132105, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826890

RESUMO

A simpler approach of functionalization for the fabrication of thiourea-functionalized-Graphene Aerogel (t-GA) is described here. Graphene Aerogel (GA) was synthesized from bio-mass, which on a simpler oxidative treatment get converted to its water-soluble version due to the impregnation of several oxygenous functionalities like carboxylic, hydroxyl, etc. Further, these carboxylated groups have been functionalized with the molecules of thiourea using the long known dicyclohexylcarbodiimide (DCC) as a coupling agent. The as-synthesized t-GA shows bright yellow fluorescence with a quantum yield of ~3% and holds the high-aqueous solubility and photostability. The fluorescence property of t-GA has been used here for the specific and selective sensing of toxic lead (Pb(II)) metal ions from the used many other metal ions via the fluorescence quenching and showed a limit of detection ~7.3 nM. Further, the mechanism for selective sensing was studied in detail and found to be preferable via ligand to metal charge transfer quenching mechanism. The cyclic voltammetry studies supported the selective sensing of Pb(II). Moreover, t-GA has also been studied for the sensing of hydrogen peroxide and as a yellow fluorescent ink.


Assuntos
Grafite , Peróxido de Hidrogênio , Íons , Chumbo , Tioureia , Água
17.
Chemosphere ; 287(Pt 2): 132156, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826898

RESUMO

In the recent decades, due to rapid increase in industrialization, urbanization, anthropogenic activity in the catchments, removal of heavy metals contaminants in wastewater has become global challenges. Numerous advance technologies have been introduced to deal with these problems but failed in reducing adequate pollution load in the contaminated water and/or wastewater. In this study, sulfur-ferromagnetic nanoparticles (SFMNs) were synthesized by modification of nano-Fe3O4, which can be rapidly separated from the environment by an external magnetic field after in situ repair. Its structure and physical properties were characterized by conventional techniques included Transmission electron microscope (TEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The ability of the SFMNs to remove Pb2+ and Cd2+ was studied at different temperatures and initial metal ions concentrations. The adsorption kinetics showed that the adsorption equilibrium time of Pb2+ and Cd2+ was 300 min consequently adsorption process of SFMNs fit well (R2 > 0.99) with pseudo-second-order model. The adsorption thermodynamics showed that the adsorption of Pb2+ and Cd2+ on SFMNs is spontaneous (negative value of ΔG0) endothermic process (positive value of ΔH0) and fit well (R2 > 0.98) with the Langmuir isothermal model. Density functional theory (DFT) calculations show that SFMNs can transfer electrons to Pb2+ and Cd2+, and the metal ions form stable chelates on the ligand surface. This study implies that newly synthesized sulfur-ferromagnetic nanoparticles could play an instrumental role in metal ions removal from water and wastewater.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Cádmio , Chumbo , Enxofre , Águas Residuárias , Poluentes Químicos da Água/análise
18.
Chemosphere ; 287(Pt 2): 132235, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826926

RESUMO

Lead (Pb) pollution has become one of the most serious environmental problems in recent decades. However, there are few remediation technologies for insoluble cerussite (PbCO3), which are common in the environment and have high bioavailability. In this study, the immobilisation of Pb(II) released from PbCO3 by Pseudomonas rhodesiae HP-7 isolated from Pb-contaminated soil was studied. The results showed that hydroxyapatite and PbCO3 were dissolved by the organic acids secreted by the HP-7 strain, and then the dissolved Pb2+ and H2PO4- reacted to form low bioavailable Pb5(PO4)3Cl precipitate. XRD and mass conservation calculations showed that 85.7% of PbCO3 was transformed to Pb5(PO4)3Cl when P:Pb was 9:5. Our research showed that the HP-7 strain and hydroxyapatite could reduce the bioavailability of Pb(II) in PbCO3, which could be used for the remediation of Pb-polluted environments.


Assuntos
Chumbo , Poluentes do Solo , Carbonatos , Durapatita , Minerais , Fosfatos , Pseudomonas , Poluentes do Solo/análise
19.
Chemosphere ; 287(Pt 3): 132190, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826933

RESUMO

Exposure to both cadmium (Cd) and lead (Pb) can promote systemic inflammation. However, the effects of combined exposure to environmental levels of Cd and Pb on systemic immune inflammation have not been fully clarified. A total of 486 subjects (313 women and 173 men) living in either a control area or heavy metal-polluted area were included. Blood Cd and Pb and immune inflammation biomarkers were determined, including the eosinophil-lymphocyte ratio (ELR), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), and systemic immune-inflammation index (SII); moreover, the associations between exposure markers and systemic inflammation markers were analysed. The exposure levels in the polluted area were significantly higher than those in the control area. The NLR, PLR, and SII of subjects in the polluted area were higher and the LMR was lower than in the control area. Blood Pb and Cd levels are associated with elevated or decreased immune inflammation biomarkers in subjects from the exposed and control areas. Furthermore, co-exposure to both Cd and Pb was divided into high, middle, and low exposure groups. The subjects in the high co-exposure group displayed higher levels of ELR, NLR, and SII compared with the middle and low co-exposure group, and LMR levels displayed the opposite trend. Our data demonstrate that Cd and Pb co-exposure is associated with systemic immune inflammation, and the immune inflammatory response is aggravated with an increased co-exposure to Cd and Pb.


Assuntos
Cádmio , Chumbo , Cádmio/toxicidade , Feminino , Humanos , Inflamação/induzido quimicamente , Linfócitos , Masculino , Neutrófilos , Estudos Retrospectivos
20.
Environ Res ; 203: 111735, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34331917

RESUMO

Following the Flint Water Crisis, many states passed legislation requiring schools to measure and remediate lead in school drinking water. In this study, we present new evidence on the level and distribution of lead in school drinking water by examining the case of New York City, which tested water from every public school fixture in the 2016-17 school year, remediated fixtures that showed elevated levels of lead above 15 ppb, and retested a sample of fixtures in 2018-19. Prior to remediation, 8 % of fixtures showed elevated levels of lead; after remediation, 5 % of fixtures did. In both pre- and post-remediation periods, Black children attended schools with a higher proportion of elevated fixtures than White, Asian, and Hispanic children. We observe post-remediation lead exposure reductions that were largest for Black children, though racial disparities in exposure remained. Together, our results show that New York City's remediation efforts significantly reduced lead in its schools' drinking water in a short period of time, providing evidence of the promise of such efforts. However, the continued presence of lead in school drinking water and persistent racial disparities in exposure demonstrate the ongoing challenges to eradicating lead exposure in schools.


Assuntos
Água Potável , Chumbo , Criança , Água Potável/análise , Humanos , Cidade de Nova Iorque , Instituições Acadêmicas
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