Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Environ Sci Pollut Res Int ; 31(30): 43381-43395, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38902447

RESUMO

There are worldwide growing concerns about environmental issues such as global warming and climate change. Moreover, it is expected that there will be regional differences in environmental issues. Therefore, this study focuses on a tri-regional comparison: America, Europe, and Asia-Pacific. Previous literature has paid less attention to exploring regional comparisons while considering regional heterogeneity. Against this backdrop, this study delves into the dynamic relationship between fossil fuel utilization, economic growth, globalization, urbanization, and CO2 emissions to understand the environmental implications of these interconnected factors. The study period spans from 1990 to 2021. Additionally, it employed rigorous tests to confirm cross-sectional dependence and data heterogeneity, following methodologies proposed by Pesaran (2004, 2015) and Pesaran (2007), utilizing the CS-ARDL panel cointegration methodology by Chudik and Pesaran (2015). The results confirm long-term significant relationships among OC, NGC, FDI, and UR variables in both combined panels, with and without regional dummies. However, GDP and COC become insignificant in the long run in the dummy variables regression. Furthermore, the regional dummies were found to be negative but remain insignificant, possibly due to heterogeneous effects or unobserved factors influencing each region independently. Analysis by region reveals predominant coal consumption in Asia, higher oil consumption in America, and greater gas consumption in Europe. Economic growth and CO2 emissions are positive in Asia and America but negative in Europe, aligning with theories prioritizing growth over environmental concerns in Asia and America, and advocating for renewable energy adoption in Europe. Urbanization increases energy demand and emissions, supporting the environmental revolution theory, while FDI holds the potential to reduce CO2 emissions, as per the endogenous growth theory.


Assuntos
Mudança Climática , Desenvolvimento Econômico , Combustíveis Fósseis , Urbanização , Dióxido de Carbono/análise , Ásia , Europa (Continente) , Aquecimento Global
2.
Heliyon ; 10(1): e23874, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38223738

RESUMO

The increasing Russia-Ukraine crisis is without a doubt Europe's most prominent conflict since World War II, changing the dynamics of the oil and other key markets. Because the oil market has traditionally interacted with other financial and commodity markets, it will be intriguing to examine how it interacts with substantial financial assets amid market volatility induced by a conflict. The goal of this study is to propose a fuzzy time series (FTS) model and to compare its competitiveness to existing fuzzy time series (FTS) models, Autoregressive Integrated Moving Average (ARIMA) model and some machine learning methods i.e. Artificial Neural Networks (ANN), Support Vector Machine (SVM) and XGBoost models. We considered changes in the partitioning universe of discourse, optimization of parameters method(s), and interval estimation to make the forecast accuracy more precise forecasting than traditional methods via MAPE. The event-based data results show the proposed fuzzy time series model is outperforming all the competitive methods in the study. Furthermore, the proposed model forecasting shows a future decline tendency in WTi market crude oil prices (US$/BBL) after being at the record highest level, which is good news for the worldwide economy.

3.
Environ Geochem Health ; 45(12): 9087-9101, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37306889

RESUMO

The widespread contamination of chlorinated paraffins (CPs) of the soil environment has raised global concern due to their highly persistent and toxic properties. However, little information is available regarding these industrial toxicants' spatial-vertical distribution and penetration potentials. In this study, short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) were analyzed in pooled surface and core soils (0-45 cm) samples collected from agricultural and industrial areas in Shanghai. ∑SCCP concentrations in agricultural and industrial surface soils ranged from 52.6 to 237.6 and 98.3 to 977.1 ng/g dry weight (dw), respectively. ∑MCCP levels were comparatively higher and ranged from 417.2 to 1690.8 and 370.9 to 10,712.7 ng/g dw in agricultural and industrial soils, respectively. C10Cl5-10 SCCPs and C14-15Cl5-7 MCCPs were the predominant homologues in all samples. Analysis of the soil vertical profiles revealed that MCCP concentrations decreased significantly with depth (P < 0.01). SCCPs more efficiently penetrated into the soils than MCCPs because of their higher water solubility and less octanol-water partition coefficient (Kow) values. A preliminary risk assessment suggested no potential health risks caused by non-dietary exposure. The daily exposure doses of CPs via ingestion were significantly (P < 0.01) higher for children (5.41 ± 2.11 × 10-3 and 1.68 ± 1.03 × 10-2 µg kg-1 day-1) and adults (2.56 ± 0.99 × 10-4 and 7.94 ± 4.87 × 10-4 µg kg-1 day-1) than dermal permeation exposure. Furthermore, CPs at current levels posed low ecological risks (0.1 ≤ RQ < 1) according to the risk quotient model. This study enhanced our understanding of the fates and behaviors of CPs in the terrestrial environment.


Assuntos
Hidrocarbonetos Clorados , Solo , Adulto , Criança , Humanos , Hidrocarbonetos Clorados/toxicidade , Hidrocarbonetos Clorados/análise , Parafina/análise , China , Monitoramento Ambiental , Medição de Risco , Água/análise
4.
Micromachines (Basel) ; 14(2)2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36838163

RESUMO

This manuscript examines the design principle and real-world validation of a new miniaturized high-performance flower-shaped radiator (FSR). The antenna prototype consists of an ultracompact square metallic patch of 0.116λ0 × 0.116λ0 (λ0 is the free space wavelength at 3.67 GHz), a rectangular microstrip feed network, and a partial metal ground plane. A novel, effective, and efficient approach based on open circuit loaded stubs is employed to achieve the antenna's optimal performance features. Rectangular, triangular, and circular disc stubs were added to the simple structure of the square radiator, and hence, the FSR configuration was formed. The proposed antenna was imprinted on a low-cost F4B laminate with low profile thickness of 0.018λ0, relative permittivity εr = 2.55, and dielectric loss tangent δ = 0.0018. The designed radiator has an overall small size of 0.256λ0 × 0.354λ0. The parameter study of multiple variables and their influence on the performance results has been extensively studied. Moreover, the impact of different substrate materials, impedance bandwidths, resonance tuning, and impedance matching has also been analyzed. The proposed antenna model has been designed, simulated, and fabricated. The designed antenna exhibits a wide bandwidth of 5.33 GHz ranging from 3.67 to 9.0 GHz at 10 dB return loss, which resulted in an 83.6% fractional impedance bandwidth; a maximum gain of 7.3 dBi at 8.625 GHz; optimal radiation efficiency of 89% at 4.5 GHz; strong intensity current flow across the radiator; and stable monopole-like far-field radiation patterns. Finally, a comparison between the scientific results and newly published research has been provided. The antenna's high-performance simulated and measured results are in a good agreement; hence, they make the proposed antenna an excellent choice for modern smartphones' connectivity with the sub-6 GHz frequency spectrum of modern fifth-generation (5G) mobile communication application.

5.
J Hazard Mater ; 446: 130631, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36586335

RESUMO

Polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) have been extensively investigated in the terrestrial environment of China. However, little is known about how PBDEs and NBFRs burdens in agricultural soils altered over time. In this study, agricultural soils from different regions of China were collected from 2011 to 2021 to investigate the contamination levels and temporal variation of PBDEs and NBFRs. The concentrations of ∑26PBDEs and ∑5NBFRs ranged from 0.144 to 215 ng/g dry weight (d.w.) and 0.186-144 ng/g (d.w.), with a mean value of 9.27 ng/g (d.w.) and 8.22 ng/g (d.w.), respectively. Among PBDEs and NBFRs, BDE-209 and decabromodiphenylethane (DBDPE) were the most predominant compounds. The PBDE concentrations did not vary significantly during the past decade, whereas the lower brominated congeners increased with time (doubling times ranged from 5.46 to 8.56 years). Meanwhile, NBFR concentrations increased over time, with concentrations significantly higher in 2021, 2016, and 2013 than in 2011 (p < 0.05). Additionally, DBDPE, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and hexabromobenzene (HBB) had doubling times of 6.84, 11.2, and 7.37 years, respectively. Total organic matter (TOC) impacted the distribution and variation of PBDEs (particularly lower-brominated congeners), with soil organic matter (SOM)-sorption showing an increasing and then decreasing trend. Health risk assessment suggested that PBDEs and NBFRs did not pose non-carcinogenic risks to humans. Nevertheless, the long-term health risk of BFRs should be considered. Overall, this is the first study to comprehensively analyze the contamination burdens and temporal trends of PBDEs and NBFRs in Chinese agricultural soils over a long period, providing a fundamental basis for future BFR management.


Assuntos
Retardadores de Chama , Éteres Difenil Halogenados , Humanos , Éteres Difenil Halogenados/análise , Monitoramento Ambiental , Solo , Retardadores de Chama/análise , China , Medição de Risco
6.
J Pak Med Assoc ; 72(5): 882-885, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35713049

RESUMO

OBJECTIVE: To assess the impact of the National External Quality Assessment Programme of Pakistan NEQAPP in improving the quality of laboratory results among the participating laboratories. METHODS: The cross-sectional observational study was conducted from July to December 2020 at the Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan, in association with the National Quality Assurance Programme of Pakistan. A survey questionnaire was developed and sent to the participating laboratories via email. Frequencies of their responses were calculated and data was analysed using SPSS 21. RESULTS: Of the 150 laboratories approached, 145(96.6%) responded. Among them, 140 (96.6%) laboratories were satisfied by the information provided on the programme's portal, 123(84.8%s) were pleased with the responsiveness of the programme manager, 140(96.6%) reported quality of services had improved after participation in the programme, 129(89%) indicated that the clinician's confidence had enhanced, and 122(84%) said the participation in the programme had improved the credibility of their respective of laboratories. CONCLUSIONS: The National External Quality Assessment Programme of Pakistan was found to have significantly contributed in improving the quality of laboratory results among the participating laboratories.


Assuntos
Laboratórios , Garantia da Qualidade dos Cuidados de Saúde , Estudos Transversais , Humanos , Paquistão , Garantia da Qualidade dos Cuidados de Saúde/métodos
7.
Environ Pollut ; 285: 117253, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33957509

RESUMO

Polychlorinated biphenyls (PCBs) may transfer into the neonates through the placental transfer and via breastfeeding after the delivery, thus might be harmful to the infant. Sixty colostrum samples in the Yangtze River Region were collected to investigate the concentration, distribution pattern, and enantiomer characteristic of the PCB exposure. Among all samples, over 90% of pollutants were tetra-to hepta-chlorinated PCBs. The sum concentration of the PCB was 512 (IQR: 322-856) ng g-1 lipid weight. Enantiomer fraction (EF) of PCB 95 and PCB 149 was found lower than the racemic value, while EFs of PCB 45 and PCB 136 were found higher and near-racemic state, respectively. The concentration pattern and enantiomeric properties of the PCBs indicated that the mothers from Mianyang had a recent exposure to PCBs. Among all samples, similar exposure and metabolic pathways of the PCB congeners were observed. PCB exposure showed no significant correlation with the birth outcome of the infants, but 43.3% of the infants have potential health risks via breastfeeding.


Assuntos
Bifenilos Policlorados , Colostro/química , Feminino , Humanos , Recém-Nascido , Placenta/química , Bifenilos Policlorados/análise , Gravidez , Medição de Risco , Rios
8.
Sci Total Environ ; 757: 143828, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33257068

RESUMO

The sixteen-priority polycyclic aromatic hydrocarbons (PAHs) were determined in twenty-one groceries from six food groups consumed by the Pakistani population. The highest concentration of the total PAHs was found in fish (243 ng g-1), while the lowest concentration was determined in rice (53 ng g-1). The total B[a]Peq dietary exposure for the male group followed an increasing order of children (865.5 ng day-1) < adolescents (2301 ng day-1) < seniors (2864 ng day-1) < adults (3004 ng day-1), whereas the similar order was also observed for the female group. The male group showed 1-8.5% (mean 5.5%) of higher exposure amount compared to the female group. Among all food categories, wheat (43%) and milk (34%) contributed the greatest while rice (1%) and egg (1%) contributed the smallest to the total dietary exposure of PAHs. The incremental lifetime cancer risk (ILCR) values for the adults and children revealed a potential cancer risk to the both male and female groups. Whereas at the 95th percentiles, the ILCR values for all age and gender groups exceeded the limit (>10-5), demonstrating a high potential cancer risk in the Pakistani population. The sensitivity analysis found that the daily dietary intake, exposure duration and the cancer slope factor were the most influential variables contributed to the total variance of risk.


Assuntos
Neoplasias , Hidrocarbonetos Policíclicos Aromáticos , Adolescente , Adulto , Animais , Criança , China , Exposição Dietética , Monitoramento Ambiental , Feminino , Humanos , Masculino , Neoplasias/induzido quimicamente , Neoplasias/epidemiologia , Paquistão/epidemiologia , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco
9.
J Hazard Mater ; 395: 122660, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32344298

RESUMO

Gestation and lactation are very sensitive and vulnerable stages for human growth and development. During these two periods, short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) can be transported to neonates via transplacental and breastfeeding transfers, and eventually posing potential adverse effects to neonates. Up to date, no simultaneous investigation of prenatal and postnatal exposure of CPs is reported. To bridge this knowledge gap, we have analyzed SCCPs and MCCPs in 20 complete sets of maternal serum, umbilical cord serum, placenta, and breast milk. The levels of both ∑SCCP and ∑MCCP followed the order of maternal serum > breast milk > cord serum > placenta. The breastfeeding transfer ratios (RBM, ≈ 1.0) of CPs were greater than the corresponding transplacental transfer ratios (RCM, < 1.0), demonstrating the higher transport of CPs during the lactation period. The placental retention/or accumulation ratios (RPM) showed that CPs were effectively retained by the placental barrier. Furthermore, the total exposure amount of SCCPs and MCCPs during the lactation period was> 100 times higher than the gestation exposure amounts. This study helps to better understand the prenatal and postnatal exposure of CPs and provides a solid basis for accurate human health risk assessment of CPs.


Assuntos
Hidrocarbonetos Clorados , Parafina , China , Monitoramento Ambiental , Feminino , Humanos , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/toxicidade , Recém-Nascido , Mães , Gravidez , Medição de Risco
10.
Environ Res ; 179(Pt B): 108828, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31704496

RESUMO

Polybrominated diphenyl ethers (PBDEs) were listed in the Stockholm Convention due to their persistent and toxic nature. In utero exposure to PBDEs might affect fetal development as it is sensitive when exposed to even low dose of xenobiotic substances during the pregnancy. In this study, a multi-centre human biomonitoring study of tri-to hexa-BDEs was conducted in three Chinese cities using 60 colostrum samples from local residents. The patterns and influencing factors, correlation with the birth outcome, and potential health risks during the breastfeeding of tri-to hexa-BDEs in the colostrum samples were assessed. The median concentration of tri-to hexa-BDEs was 9.1 (Interquartile range: 3.1-19.5) ng g-1 lipid weight, and BDE-153 contributed 68% of the detected PBDEs. The PBDE levels were mostly associated with maternal age and drinking water sources, while correlations with other factors including weight gain, BMI, parity and the number of aborted pregnancies was not significant. The level of BDE-28 was positively correlated with the birth weight, while the BDE-99 was positively correlated with the head circumference, using multilinear regression. For the total hazard quotients, 60% of the infants have an estimated value higher than 1, showed potential chronic hazard for future development and possible adverse health effects to the babies from the exposure to PBDE congeners. Alternative food source seems to have a lower risk for neonates than the colostrum, but the advantages of breastfeeding undoubtedly outweigh the risks and potential adverse health effects caused by environmental PBDEs and other xenobiotic chemical exposure.


Assuntos
Colostro/metabolismo , Poluentes Ambientais/metabolismo , Éteres Difenil Halogenados/metabolismo , Exposição Materna/estatística & dados numéricos , Monitoramento Biológico , Carga Corporal (Radioterapia) , China , Cidades , Monitoramento Ambiental , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Medição de Risco
11.
Environ Pollut ; 240: 116-124, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29730420

RESUMO

Given its wide distribution in the natural environment and global transport potential, mercury (Hg) is regarded as a ubiquitous pollutant. In this study, we carried out nation-wide sampling campaigns across China to investigate the distribution of Hg in agricultural soils. Concentrations of Hg in the soils collected in 2011 and 2016 ranged from 0.04 to 0.69 and 0.06-0.78 mg kg-1, respectively. Based on the data from 2016, the reserve of Hg in the surface arable soils (0-20 cm) in China was 4.1 × 104 metric tons and Chinese cultivated soils accounted for 63.4-364 metric tons of Hg released to the global atmosphere. The soil Hg concentrations were significantly higher than the reference background level, highlighting the impacts of anthropogenic activities. The vertical distribution pattern showed a clear enrichment at the surface and a decrease with depth of the soils. Comparison of calculated geo-accumulation indexes among individual provinces showed that Northwest China had higher levels of Hg contamination than other regions of China, likely due to long-term energy related combustions in the area. Soil Hg level showed strong positive correlations with organic matter contents of soil, as well as the mean annual precipitation and temperature of the sampling locations. The non-carcinogenic human health risks of soil Hg were below the threshold level, but the general risk to the ecosystem was considerable. The increases in Hg accumulation from 2011 to 2016 at provincial level were found to relate to coal combustion, power generation and per capita GDP. This examination of energy consumption and socioeconomic drivers for China's soil Hg reserve increase is critical for direct Hg control by guiding policy-making and targets of technology development in era of rapid economic growth.


Assuntos
Agricultura , Monitoramento Ambiental , Mercúrio/análise , Poluentes do Solo/análise , Solo/química , Atmosfera , China , Carvão Mineral/análise , Humanos , Medição de Risco
12.
Environ Geochem Health ; 39(4): 779-790, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27356508

RESUMO

Hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) metabolites were analyzed in sediments of three different depths (0-10, 10-20 and 20-30 cm) collected from Kabul River, Pakistan, in February 2014. The occurrence levels, enantiomer fractions and potential ecological risk of these organochlorine pesticides (OCPs) were evaluated. The total concentrations of ∑HCHs and ∑DDTs in surface sediments ranged from 4.9-23.9 ng g-1 and from 6.4-18.8 ng g-1 (dry weight basis), respectively. The vertical contamination profile of DDTs was found in order of 20-30 cm >10-20 cm >0-10 cm, indicated that the residue levels of DDTs gradually decreased after it was banned. The ratios of ß-HCH/HCHs ranged from 0.04 to 0.73 (69 % of samples below 0.5) suggesting the fresh input of HCHs, while isomeric ratios of α-HCH/γ-HCH (ranged from 0.02 to 7.94), with 76 % of samples less than 3, indicating the cocktail use of technical grade HCH and lindane in the study area. The ratio of (DDE + DDD)/DDTs (ranged from 0.42 to 0.90) indicated long-term biodegradation of parent DDT. The enantiomer of α-HCH was generally racemic or close to racemic for most of the samples, with enantiomeric fraction (EF) value <0.5 for some of the samples indicated the preferential biodegradation of (+)-α-HCH enantiomer, while for o,p'-DDT the EF values >0.5 indicated the depletion of (-)-o,p'-DDT enantiomer in most of the samples. According to sediment quality guidelines (SQGs), HCH contamination is the main concern for ecotoxicological risk in Kabul River.


Assuntos
DDT/análise , Sedimentos Geológicos/química , Hexaclorocicloexano/análise , Inseticidas/análise , Rios/química , Poluentes Químicos da Água/análise , DDT/química , Monitoramento Ambiental , Hexaclorocicloexano/química , Inseticidas/química , Isomerismo , Paquistão , Medição de Risco , Poluentes Químicos da Água/química
13.
Environ Sci Pollut Res Int ; 23(12): 12227-36, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26971962

RESUMO

This study aimed to investigate the potential health risk associated with toxic metals in contaminated foodstuffs (fruits, vegetables, and cereals) collected from various agriculture fields present in chromite mining-affected areas of mafic and ultramafic terrains (northern Pakistan). The concentrations of Cr, Ni, Zn, Cd, and Pb were quantified in both soil and food samples. The soil samples were highly contaminated with Cr (320 mg/kg), Ni (108 mg/kg), and Cd (2.55 mg/kg), which exceeded their respective safe limits set by FAO/WHO. Heavy metal concentrations in soil were found in the order of Cr>Ni>Pb>Zn>Cd and showed significantly (p < 0.001) higher concentrations as compared to reference soil. The integrated pollution load index (PLI) value was observed greater than three indicating high level of contamination in the study area. The concentrations of Cr (1.80-6.99 mg/kg) and Cd (0.21-0.90 mg/kg) in foodstuffs exceeded their safe limits, while Zn, Pb, and Ni concentrations were observed within their safe limits. In all foodstuffs, the selected heavy metal concentrations were accumulated significantly (p < 0.001) higher as compared to the reference, while some heavy metals were observed higher but not significant like Zn in pear, persimmon, white mulberry, and date-plum; Cd in pear, fig and white mulberry; and Pb in walnut, fig, and pumpkin. The health risk assessment revealed no potential risk for both adults and children for the majority of heavy metals, except Cd, which showed health risk index (HRI) >1 for children and can pose potential health threats for local inhabitants. Graphical Abstract Heavy metals released from chromite mining lead to soil and foodstuff contamination and human health risk.


Assuntos
Metais Pesados/análise , Mineração , Medição de Risco , Poluentes do Solo/análise , Grão Comestível/química , Frutas/química , Paquistão , Solo , Verduras/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA