خيارات البحث
النتائج 4061 - 4070 من 8,010
Effects of atrazine short-term exposure on jumping ability and intestinal microbiota diversity in male Pelophylax nigromaculatus adults النص الكامل
2021
Zhao, Qiang | Huang, Minyi | Liu, Yang | Wan, Yuyue | Duan, Renyan | Wu, Lianfu
Atrazine, a common chemical pesticide, has toxicity to adult and juvenile amphibians in natural ecosystems; however, it is more common to study its effects on larvae instead of adults. This study assessed the impacts of atrazine in water through short-term exposure (7 days) on male black spotted frog (Pelophylax nigromaculatus) adults fed every day. The jumping ability, including jumping height, distance, time, and speed, was measured by 3D motion analysis software, and the intestinal content microbiota was determined by 16S rRNA amplicon sequencing with QIIME software. The results showed that male P. nigromaculatus exposure to 200 and 500 μg/L atrazine significantly increased jumping distance and jumping time compared to control groups. Conversely, 500 μg/L atrazine treatments significantly decreased the diversity and changed the composition and structure of intestinal content microflora in male P. nigromaculatus compared to control groups. At the phylum level, Chlamydiae was only detected in the control group, and Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria were the dominant microflora in the atrazine treatment groups. At the genus level, the abundance of Lactobacillus and Weissella significantly increased in atrazine treatment groups compared to control groups. This study can provide a new framework based on movement behavior and intestinal microbiota to evaluate the response of amphibians to short-term exposure to environmental pollution.
اظهر المزيد [+] اقل [-]Chitosan Versus Chitosan-Vanillin Modified: An Evaluation of the Competitive Adsorption of Five Emerging Contaminants النص الكامل
2021
dos Santos Cardoso, Carolina | Vitali, Luciano
Emerging contaminants (ECs) have been studied extensively because of the various damages they can cause to the environment, especially due to the non-treated domestic effluents, which contaminate the water bodies. Therefore, it is important to evaluate alternatives to remove these compounds. The objective of this work was to evaluate the potential of a new biosorbent from chitosan modified with vanillin (CTSV) to remove isoniazid, cortisol, bisphenol A, 17α-ethinylestradiol, and triclosan by competitive adsorption studies. Structural characterization of the biosorbents was performed by Fourier transform infrared spectroscopy, thermogravimetry, Brunauer-Emmett-Teller, zeta potential, scanning electron microscopy, and ¹H nuclear magnetic resonance. The adsorption for ECs were carried out in an aqueous medium, and quantitative analyzes were performed by HPLC. The effect of pH was evaluated in the pH range 5 to 10 and indicated that better results were found in pH 9 and 8 for CTS and CTSV, respectively. The salt concentrations effect was evaluated in 0.0 to 1.0 mol L⁻¹ and revealed better adsorption conditions in 0.7 mol L⁻¹ of NaCl. The adsorption kinetics pointed to an equilibrium condition reached quickly (with adjustment of data R² > 0.969) with adequacy to pseudo–second-order model for both biosorbents and ECs. The linear isothermal model was suitable for the adsorption isothermal data and distribution constant (KD) showed the highest values for 17α-ethinylestradiol (0.067 L g⁻¹) and triclosan (0.197 L g⁻¹) in CTSV adsorption. Thus, the results indicated that CTSV performed well in removal for the tested ECs, being an interesting alternative, due to the ease of obtaining and abundance of reagents employed in its preparation.
اظهر المزيد [+] اقل [-]Prevalence of hearing loss and influencing factors among workers in Wuhan, China النص الكامل
2021
Li, Wenzhen | Zhao, Zhiya | Chen, Zhenlong | Yi, Guilin | Lu, Zuxun | Wang, Dongming
We aimed to estimate the prevalence of hearing loss and influencing factors among workers in automobile manufacturing industry in Wuhan, China. We conducted cross-sectional analyses of 2017 through 2019 data from survey of the key occupational diseases on 17,176 workers in automobile manufacturing industry, Wuhan, China. Hearing loss was defined as a pure tone mean of 25 dB or higher in either ear at 0.5, 1, and 2 kHz for speech frequency and at 3, 4, and 6 kHz for high frequency. Among the 17,176 workers, more than a quarter of participants had high frequency hearing loss, and 6.41% had speech frequency hearing loss. The prevalence of hearing loss was higher among participants with diabetes mellitus and current smoking, temporary tinnitus, and sudden change in hearing. Compared with the controls, age (OR = 1.08, 95% CI = 1.08–1.09), male (OR = 1.40, 95% CI = 1.21–1.63), occupational noise exposure (OR = 1.19, 95% CI = 1.08–1.30), having temporary tinnitus (OR = 1.20, 95% CI = 1.08–1.33), and having sudden change in hearing (OR = 1.58, 95% CI = 1.20–2.08) were associated with higher prevalence of high frequency hearing loss; meanwhile, age (OR = 1.09, 95% CI = 1.08–1.09), male (OR = 1.38, 95% CI = 1.11–1.71), having family history of hearing loss (OR = 2.84, 95% CI = 1.35–5.97), and having sudden change in hearing (OR = 2.58, 95% CI = 1.80–3.70) were associated with higher prevalence of speech frequency hearing loss. No additive and multiplicative interaction was found between occupational noise and these factors for hearing loss. Hearing loss directly affects 25% of workers in automobile manufacturing industry in Wuhan. Measures should be implemented for the control of occupational noise and other factors simultaneously in the workplace.
اظهر المزيد [+] اقل [-]Outdoor/Indoor Contaminant Transport by Atmospheric Dust and Aerosol at an Active Smelter Site النص الكامل
2021
Rodríguez-Chávez, Tania B. | Rine, Kyle P. | Almusawi, Reman M. | O’Brien-Metzger, Ruby | Ramírez-Andreotta, Mónica | Betterton, Eric A. | Sáez, A. Eduardo
Activities associated with mining operations including smelting, ore handling, and mine tailings management have been identified as sources of dust and aerosol that may contain metal and metalloid contaminants, such as lead (Pb) and arsenic (As). Previous studies on contaminant transport have concentrated on the potential impact of these particulate emissions in outdoor environments. The purposes of this study were (i) to quantify the effect of dust and aerosol particle size on contaminant transport from outdoor-to-indoor environments and (ii) to document the changes in particle chemical composition during transport through the outdoor/indoor barrier. Outdoor and indoor particulate samples were collected at a high school equipped with mechanical air filtration systems from 2016 to 2019. The school is located near a set of mine tailings and an active copper smelter in Hayden, Arizona. Particle size segregated samples were collected using a ten-stage micro-orifice uniform deposit impactor (MOUDI). Results show that airborne fine particles (aerodynamic diameters less than 1 micron) can penetrate to the indoor environment but in a reduced amount due to mechanical filtration. Aerosol in the fine fraction particulate air concentrations was around 50% of the corresponding outdoor values, but their mass concentration of contaminants was similar to outdoor values. Indoor coarse particles (> 1 micron) comprised close to 20% of the levels found in outdoor coarse particles. These results highlight the need to consider the impact of particle diameter when assessing indoor exposure and potential health effects in communities living under the direct influence of mining and smelter activities.
اظهر المزيد [+] اقل [-]Application of an electrochemical sensor using copper oxide nanoparticles/polyalizarin yellow R nanocomposite for hydrogen peroxide النص الكامل
2021
Amini, Nader | Rashidzadeh, Bahaaldin | Amanollahi, Nasrin | Maleki, Afshin | Yang, Jae-Kyu | Lee, Seung-Mok
In this study, copper oxide nanoparticles (CuONPs) were prepared by a simple chemical method and then characterized by scanning electron microscope (SEM). A novel electrochemical sensor for hydrogen peroxide (H₂O₂) analysis was prepared by immobilizing copper oxide nanoparticles and polyalizarin yellow R (PYAR) on bare glassy carbon electrode (PAYR/CuONPs/GCE). The electrocatalytical behavior of the proposed electrochemical sensor was also studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Based on the results, the PAYR/CuONP nanocomposite had significant electrocatalytic oxidation and reduction properties for the detection and determination of H₂O₂. Some parameters such as linear range, sensitivity, and detection limit for reduction peak were obtained as 0.1–140 μM, 1.4154 μA cm⁻² μM⁻¹, and 0.03 μM, respectively, by the DPV technique. Some advantages of this electrode were having widespread linear range, low detection limit, and, most importantly, ability in simultaneous oxidation and reduction of H₂O₂ at two applied potentials.
اظهر المزيد [+] اقل [-]Co-disposal of lignite fly ash and coal mine waste rock for neutralisation of AMD النص الكامل
2021
Qureshi, Asif | Maurice, Christian | Öhlander, Björn
Waste rocks (WRs) from a lignite-producing coalfield and fly ash (FA) produced from the same lignite have been investigated in this study with a primary objective to determine the potential for co-disposal of WRs and FA to reduce the environmental contamination. Mixing WRs with FA and covering WRs with FA have been investigated. Particle size effect caused ≤2 mm particles to produce low pH (~2) and metal-laden leachates, indicating higher sulphide minerals’ reactivity compared to larger particles (≤10 mm, pH ~ 4). Co-disposal of FA as mixture showed an instantaneous effect, resulting in higher pH (~3–6) and better leachate quality. However, acidity produced by secondary mineralisation caused stabilisation of pH at around 4.5–5. In contrast, the pH of the leachates from the cover method gradually increased from strongly acidic (pH ~ 2) to mildly acidic (pH ~ 4–5) and circumneutral (pH ~ 7) along with a decrease in EC and elemental leaching. Gradually increasing pH can be attributed to the cover effect, which reduces the oxygen diffusion, thus sulphide oxidation. FA cover achieved the pH necessary for secondary mineralisation during the leaching experiment. The co-disposal of FA as cover and/or mixture possesses the potential for neutralisation and/or slowing down AMD and improving leachate quality.
اظهر المزيد [+] اقل [-]Genotoxicity, oxidative stress, and inflammatory response induced by crack-cocaine: relevance to carcinogenesis النص الكامل
2021
Malacarne, Ingra Tais | De Souza, Daniel Vitor | Rosario, Barbara Dos Anjos | Viana, Milena De Barros | Pereira, Camilo Dias Seabra | Estadella, Debora | dos Santos, Jean Nunes | Ribeiro, Daniel Araki
Crack-cocaine is a cocaine by-product widely consumed by general population in developing countries. The drug is low cost and is associated with more intense effects when compared to other illicit drugs. Genotoxicity, oxidative stress, and inflammatory response are considered crucial events in carcinogenesis, since they actively participate in the multistep process. The purpose of this paper was to provide a mini review regarding the relationship between carcinogenesis and genotoxicity, oxidative stress, and inflammation induced by crack-cocaine. The present study was conducted on search of the scientific literature from the published studies available in PubMed, MEDLINE, Scopus, and Google Scholar for all kind of articles (all publications to November 2020) using the following key words: crack-cocaine, DNA damage, genotoxicity, cellular death, cytotoxicity, mutation, oxidative stress, inflammation, and mutagenicity. The results showed that published papers available were almost all in vivo test system being conducted in humans or rodents. Crack-cocaine was able to induce genotoxicity and oxidative stress in mammalian cells. However, the role of inflammatory response after exposure to crack-cocaine was not conclusive so far. In summary, this study is consistent with the notion that crack-cocaine is a chemical carcinogen as a result of genotoxicity and oxidative stress induced in mammalian and non-mammalian cells.
اظهر المزيد [+] اقل [-]Investigating the factors underlying participation by the Chinese public in environmental management: an approach based on spatial heterogeneity النص الكامل
2021
Tong, Yun | Zhou, Haifeng | Jiang, Lei | He, Biao
Public participation in environmental management (PPEM) in China has become increasingly prominent; thus, investigating the factors that underlie participation by the Chinese public in environmental management is important. To this end, we adopted unique data for PPEM, which was measured based on environmental complaints logged by the telephone hotline set up by the Ministry of Ecology and Environment of China. We observed that PPEM greatly varied from one city to another, indicating significant spatial heterogeneity. In addition, complaints were mainly concentrated in four large regions, namely, the North China Plain, the Yangtze River Delta, the Pearl River Delta, and the Chengdu-Chongqing urban agglomeration. Next, a newly developed spatial heterogeneity analysis method, namely, geographical detector, was applied to investigate the driving factors of PPEM. From the factor detector analysis results, we confirmed that the economic level, energy consumption, urban population, college-educated population, wastewater, environmental risk, SO₂ emissions, and PM₂.₅ concentrations were the dominant factors that caused citizens to voice environmental complaints. In addition, we noticed that moderately developed cities were the leading risk areas, which indicated that these cities had serious environmental pollution problems and their citizens actively voiced complaints. As economies continue to grow, the populations in these cities are projected to become more aware of environmental quality and will implement stricter regulations to protect the environment and lower complaints. Moreover, the interaction detector analysis results revealed that the interaction of urban and college-educated populations with other factors played more important roles in affecting PPEM.
اظهر المزيد [+] اقل [-]Analysis of factors affecting alcohol and tobacco concurrent use by bivariate probit model in Turkey النص الكامل
2021
Alkan, Ömer | Abar, Hayri | Gençer, Özge
Alcohol and tobacco use are risky factors that are associated with one another. High alcohol and tobacco use are significant public health problems with social and economic costs and one of the leading causes of preventable death and disease. The aim of this study was to determine the sociodemographic and economic factors on alcohol and tobacco concurrent use. In this study, a bivariate probit model was employed to determine the factors affecting alcohol and tobacco concurrent use among individuals aged 15 and above who were living in Turkey. The data used in this study was obtained from the Turkey Health Survey conducted in 2010, 2012, 2014, and 2016 by the Turkish Statistical Institute. The data were gathered from a total of 77,327 individuals. Empirical findings suggest that factors affecting alcohol and tobacco use were simultaneous. Also, the results revealed that several key variables such as age, gender, educational status, marital status, household monthly income level, and survey year were significant determinants of alcohol and tobacco concurrent use. Psychosocial support is significant for only tobacco use. In the last decade, a number of restrictions aimed to combat alcohol and tobacco use have been associated with reducing the usage habits of individuals. This is the first study that simultaneously compared both alcohol use and tobacco use using a Turkish sample.
اظهر المزيد [+] اقل [-]Occurrence of contaminants of emerging concern in surface waters from Paraopeba River Basin in Brazil: seasonal changes and risk assessment النص الكامل
2021
Corrêa, Joane M. M. | Sanson, Ananda L. | Machado, Célia F. | Aquino, Sérgio F. | Afonso, Robson J. C. F.
This study describes the application of gas chromatography coupled to mass spectrometry (GC-MS) to evaluate the occurrence of 12 CECs—contaminants of emerging concern (bisphenol A, diclofenac, 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, gemfibrozil, ibuprofen, naproxen, 4-nonylphenol, 4-octylphenol, and acetaminophen) in surface waters from Paraopeba River Basin, Minas Gerais State, Brazil. The analytical procedure was validated and applied to 60 surface water samples collected across four sampling campaigns along the upper and middle watershed. Methods for CECs determination involved sample filtration, and solid-phase extraction (SPE) with subsequent derivatization of the target compounds prior to their analysis by GC-MS. The LOQ varied from 3.6 to 14.4 ng/L and extraction recoveries ranged from 46.1 to 107.1% for the lowest spiked concentration level (10 ng/L). The results showed a profile of spatial distribution of compounds, as well as the influence of rainfall. Ibuprofen (1683.9 ng/L), bisphenol (1587.7 ng/L), and naproxen (938.4 ng/L) occurred in higher concentrations during the rainy season, whereas during the dry season, the concentrations of bisphenol (1057.7 ng/L), estriol (991.0 ng/L), and estrone (978.4 ng/L) were highlighted. The risk assessment of human exposure shows that for most contaminants, the concentration is well below the estimated thresholds for chronic toxicity from water intake. However, estradiol and 17α-ethinylestradiol showed concentrations in the same order of magnitude as the guide values estimated for babies.
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