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The possibility of using Scots pine needles as biomonitor in determination of heavy metal accumulation Texto completo
2020
Alaqouri, Houriyah Ateeyah Alwizri | Genc, Cigdem Ozer | Aricak, Burak | Kuzmina, Nadezhda | Menshikov, Sergey | Cetin, Mehmet
One of the biggest problems of modern world is the air pollution which causes the death of millions of people every year. The heavy metals included in the component of air pollution occupy an important position in human health since they could remain intact in nature for a long time and build bioaccumulation, and also some of them are toxic or carcinogenic even at some low concentrations. Even the heavy metals functioning as micronutrient element could create toxic effect for human beings at the high concentrations. For this reason, the determination of the heavy metal concentration has an important role in terms of the detection of risky regions and risky level. One of the primary sources of heavy metals is industrial plants where the heavy metal ores are processed. Those regions might have risks at high level in terms of particular heavy metals. Consequently, it is significant to find out in which level they influence the area around these plants and to what extent the heavy metal pollution is effective. In this study, Ba, Zn, Cd, K, and Na concentrations are determined by analyzing the samples which are taken from 1- and 2-year-old needles of Scots pines (Pinus sylvestris L.) growing in 1 km, 3 km, 10 km and 25 km distances around a processing and mining of magnesite ore in Russia. In the end of the study, it is concluded that generally, the concentrations of heavy metals subject to the study are increasing depending upon the distance, and this increase is quite apparent in some elements, and finally in many points, the concentrations determined in 2-year-old needles have higher levels than 1-year-old needles.
Mostrar más [+] Menos [-]Optimal regulation of N/P in horizontal sub-surface flow constructed wetland through quantitative phosphorus removal by steel slag fed Texto completo
2020
Chen, Xiurong | Sun, Xiaoli | Xu, Peng | Wang, Shanshan | Zhou, Tianjun | Wang, Xiaoxiao | Yang, Chenchen | Lu, Quanling
High concentration of nitrogen and phosphorus and imbalance of N/P can lead to the formation of water and the malignant proliferation of toxic microalgae. This study put forward the advanced nutrient removal with the regulation of effluent N/P as the core in order to restrain the eutrophication and growth of poisonous algae. According to the preliminary study and review, the optimal N/P for non-toxic green algae was 50:1. The horizontal sub-surface flow constructed wetland was filled with steel slag and ceramsite to achieve the regulation of effluent N/P. The results showed that steel slag had the stable P removal capacity when treating synthetic solution with low P concentration and the average removal rate for 1.5, 1.0, and 0.5 mg/L synthetic P solution was 2.98 ± 0.20 mg kg⁻¹/h, 2.26 ± 0.15 mg kg⁻¹/h, and 1.11 ± 0.10 mg kg⁻¹/h, respectively. Combined with P removal rate and P removal task, the filling amount of steel slag along the SSFCW (sub-surface flow constructed wetland) was 3.22 kg, 4.24 kg, and 4.31 kg. In order to ensure the stability of dephosphorization of steel slag, the regeneration of P removal capacity was investigated by switching operation of two parallel SSFCW in 20 days for cycle. The N removal was limited for the deficiency of carbon source (COD (chemical oxygen demand)/TN = 3–4), and was stable at 18.5–31.9% which was less affected by temperature. Therefore, by controlling the process of quantitative P removal of steel slag, the effluent N/P in SSFCW can be stable at 40–60:1 in the whole year, so as to inhibit the malignant proliferation of toxic algae.
Mostrar más [+] Menos [-]Validation of particulate dispersion models by native lichens as point receptors: a case study from NE Italy Texto completo
2020
Fortuna, Lorenzo | Incerti, Guido | Da Re, Daniele | Mazzilis, Denis | Tretiach, Mauro
Atmospheric dispersion model (ADM) simulations are increasingly used as management tools in air pollution monitoring programs, even in the absence of proper validation. Biomonitors can provide important information for ADM validation, but an open question is their temporal frame of application, particularly when native organisms are used. In this study, we tested two alternative ADM simulating the total suspended particulate (TSP) released by a coal power station, against the element content of two native lichens collected at 40 sites, integrated by soil samples. The ADM simulations differed by the time references: the 6-month period preceding lichen sampling, approximately corresponding to the estimated age of the samples (Mod. A), and the whole year 2005, representative of the local average conditions and used in the plant authorization processes (Mod. B). A generalized regression model analysis clearly showed that the Cr, Pb and V content of lichen samples was spatially associated to the outcomes of Mod. A, but not with Mod. B. Interestingly, the Cr content of lichen samples consistently correlated to TSP concentration predicted by Mod. A along two transects placed downwind from the coal power station. This result was corroborated by an air particulate matter sampling which pointed out that air Cr concentrations increased during the operative period of the source. Overall, our results suggest that lichen bioaccumulation data can proficiently be used to validate ADM simulations if the exposure time of the biological samples is consistent with the temporal domain of the ADM simulations.
Mostrar más [+] Menos [-]A novel modeling approach for a generalizable photo-Fenton-based degradation of organic compounds Texto completo
2020
Audino, Francesca | Pérez-Moya, Montserrat | Graells, Moisès | Espuña, A. | Csukás, Béla | Varga, Mónika
This work aims at proposing and validating a model that can be exploited for the future development of industrial applications (e.g., process design and control) of Fenton and photo-Fenton processes. Hence, a compromise modeling solution has been developed between the non-generalizable accuracy of the first principles models (FPMs) and the oversimplification of the empirical models (EMs). The work presents a novel model of moderate complexity that is simplified enough to be generalizable and computationally affordable, while retaining physical meaning. The methodology is based on a general degradation mechanism that can be algorithmically generated from the carbon number of the target compound, as well as from the knowledge of two kinetic parameters, one for the faster initial rate and the other one for the subsequent degradation steps. The contaminant degradation mechanism has been combined with an appropriately simplified implementation of the well-known Fenton and photo-Fenton kinetics. This model describes the degradation not only of the target compound and of the oxidant, but also of total organic carbon (TOC), which is used to define the overall quality of the water. Experimental design techniques were used along with a non-conventional modeling methodology of programmable process structures (PPS). This novel modeling approach was applied and validated on the degradation of three model compounds. A successful prediction of the evolution of the contaminants H₂O₂ and TOC was confirmed and assessed by the root mean square error (RMSE).
Mostrar más [+] Menos [-]Larvicidal and repellant effects of Jussiaea repens (L.) leaf ethanol extract and its major phyto-constituent against important human vector mosquitoes (Diptera: Culicidae) Texto completo
2020
Krishnappa, Kaliyamoorthy | Baranitharan, Mathalaimuthu | Elumalai, Kuppusamy | Pandiyan, Jeganathan
Jussiaea repens (L.) leaf ethanol extract (LEE) and its major phyto-compound (MPC) have effects against larvae and adults of dengue, malarial, and filarial vectors. Total larval death rates were recorded from LEE and MPC has significant larval killing activity with LC₅₀/LC₉₀ values of Ae. albopictus, An. stephensi, and Cx. quinquefasciatus that were 118.3/229.9, 116.1/216.8, 114.4/213.5 and 17.7/27.5, 15.6/25.4 and 12.3/21.1 μg/ml, respectively. A best repellent activity was ascertained at 3.057 mg/cm² concentration of LEE and MPC provided 100% protection upto 240 min against selected human vector mosquitoes (HVMs). The functional groups were confirmed by FT-IR analysis and their presence in ethanol extract and mass spectral analysis: 4-piperidineacetic acid, 1-acetyl-5-ethyl-2-[3-(2-hydroxyethyl]-1H-indol-2-yl]-á-methyl-, methyl ester compound was identified in the LEE. The results obtained suggest that J. repens LEE and its MPC were important and responsible for health protection and control of HVMs.
Mostrar más [+] Menos [-]The association between the diesel exhaust particle exposure from bus emission and the tubular epithelial cell deformation of rats Texto completo
2020
Wardoyo, Arinto Yudi Ponco | Juswono, Unggul Pundjung | Noor, Johan Andoyo Effendi
The diesel vehicle emissions regarding particles have become a problem due to human health adversely. Especially ultrafine particles (diameter ≤ 100 nm) can deeply penetrate the human body leading to cell deformation. Investigation of the diesel ultrafine particle exposure to the cell deformation has become a challenge to build up understanding the impacts of ultrafine particles on human health. Moreover, the relationship between high exposure to diesel ultrafine particles and the deformation of the rat’s tubular epithelial cells is not clear. In this study, we investigated the impact of the diesel ultrafine particle exposure to the rat’s tubular cells. Three diesel busses were used as the sources of the particles, while 50 rats were used as the experimental animals. The diesel emission was filtered using an N95 particulate filter and a suction pump. The rats were exposed to the diesel ultrafine particle emission for 100 s with three different concentrations C₁, C₂, and C₃ for eight consecutive days. All rats were sacrificed on the day after exposures to examine the histological images. The results showed that the deformation level of the tubular epithelial cells was positively associated with the concentration of the ultrafine particles.
Mostrar más [+] Menos [-]Mechanism study on co-processing of water-based drilling cuttings and phosphogypsum in non-autoclaved aerated concrete Texto completo
2020
Wang, Chao-qiang | Mei, Xu-dong | Zhang, Chun | Liu, Dong-sheng | Xu, Feng-lin
The feasibility of coordinated use of water-based drilling cuttings (WDC), fly ash, and phosphogypsum (PG) as raw materials for the preparation of WDC non-autoclaved aerated concrete (WNAAC) was evaluated by laboratory experiment. The results showed that the pozzolanic reaction of the multi-component cementitious system containing 40% (in mass) of WDC is significantly promoted. Newly formed C-S-H gel and ettringite with the uniform distribution of fibrous and flake-like shape occur, presenting a denser and interlock microstructure. In addition, after cured by steam at 80 °C for 24 h, the mechanical property and unit weight of the WNAAC prepared with 40% WDC fully meet the B06, A3.5 grade of China state standard (GB/T11968-2006). Environmental performance tests confirm that the WNAAC prepared with 40% WDC does not create any secondary contamination.
Mostrar más [+] Menos [-]Variations in soil organic carbon decompositions of different land use patterns on the tableland of Loess Plateau Texto completo
2020
Liu, Mengyun | Liu, Mengmeng | Li, Peng | Yang, Jinghan | Wang, Jing | Chang, Qingrui
Land use patterns are one of the critical factors affecting soil carbon sequestration or decomposition and greenhouse gas emissions. The accurate evaluation of its change is particularly crucial for the carbon cycle of the terrestrial ecosystem and global climate change. This paper examined the dynamic soil respiration by means of the indoor airtight culture method and static box-gas chromatography under the land uses of the farmland, natural grassland, shrub forestland, arbor and shrub mixed forestland, and arbor forestland on the tableland of Loess Plateau. The results showed that soil organic carbon mineralization and soil respiration rate were influenced by the land use type. (1) The content and rate of soil mineralizable carbon in grassland were significantly higher than that in forestland and farmland, and that in forestland significantly higher than that in the farmland (P < 0.05). The trend of organic carbon mineralization was rapid in the initial stage of culture (by the rate of 30.02~238.56 mg kg⁻¹ h⁻¹ in the first 0.5 h) and slowed down in the later stage (by the rate of 1.07~1.95 mg kg⁻¹ h⁻¹ in 1575 h). In the soil of grassland, the accumulation of mineralizable organic carbon in the 0–5-cm layer was 1.20~1.64 times that in the soil of forestland and 1.82 times that of farmland. Compared with the 0–5-cm soil layer, there were decreases in the 5–20-cm soil layer under all land uses, with a decline of up to 48% in farmland. (2) The soil carbon mineralization potential of different land use types ranged from 0.81 to 2.70 mg kg⁻¹, that of grassland was significantly higher than that of farmland (P < 0.05), and the soil organic carbon decomposition rate constant (k) under shrub forestland was significantly higher than that under other land use types (P < 0.05). The highest organic carbon mineralization capacity and the lowest sequestration were in the soil of farmland, while that in grassland had the lowest organic carbon mineralization capacity and the highest sequestration. (3) The cumulative amount of soil respiration was highest under the natural grassland, followed by the shrub forestland, and lowest under the farmland. The soil respiration rate was positively correlated with soil temperature, and its correlation with soil water content was positive in the wet season (May through October) and negative in the dry season (November through April in the following year). (4) The soil respiration rate showed obvious seasonal differences. After the conversion of farmland to forestland, it would be rising in the content of soil organic carbon and labile organic carbon, and be going down in the temperature sensitivity (Q₁₀). In summary, by converting farmland to forestland or grassland, the sequestration of soil organic carbon had greatly been enhanced, and the possibility of soil greenhouse gas emissions had reduced on the tableland of Loess Plateau.
Mostrar más [+] Menos [-]Effect of waterpipe dependence on risk motives, attitudes and other health-related risky behaviors in Lebanese university students Texto completo
2020
Hallit, Souheil | Sacre, Hala | Salameh, Pascale
Explore whether waterpipe dependence in young Lebanese adults would have any effect on modifying the association between risk conception, attitude, and other risky behaviors. A cross-sectional study was carried out using a proportionate cluster sample of Lebanese university students (3384 students). Waterpipe dependence was associated with higher association of alcohol dependence and cigarette dependence by 76.7% and higher excitement for dangerous behaviors by 7.1%. It was significantly associated with increased association of cigarette dependence and alcohol dependence by 66.8%, with the thinking of a behavior of being not dangerous by 239%, with having motives for risky behaviors by 74.1%, with ever having unsafe sex by 111.74%, and between having motives for risky behaviors and ever having unsafe sex by 61.95%. Waterpipe dependence was associated with higher motives, excitement, and perception of risk and risky behaviors, namely cigarette dependence, alcohol dependence, and unsafe sex. Moreover, it was associated with higher risky behavior interdependence.
Mostrar más [+] Menos [-]Effect of acid-treated and hexadecyltrimethylammonium bromide–modified montmorillonites on adsorption performance of mycotoxins Texto completo
2020
Mao, Jiaqi | Lv, Guanglie | Zhou, Renxian
A series of modified montmorillonites treated by acid and hexadecyltrimethylammonium bromide (HTAB) were prepared and characterized, and their adsorption performances for three mycotoxins (aflatoxin B1, zearalenone, and deoxynivalenol) were evaluated at pH 2.8 and 8.0, respectively. The results indicate that the layers of raw montmorillonite are exfoliated after acid treatment and more active sites for adsorption of weak polar mycotoxins are exposed. While the intercalation of HTAB leads to an obvious increase of the interlamellar spacing and hydrophobic character of montmorillonite. The HTAB-AMMT-3 modified by acid and HTAB exhibits excellent adsorption capacity towards aflatoxin B1 (AFB1) and zearalenone (ZEA) whether in acidic or alkaline conditions compared with raw montmorillonite (MMT). However, all modified montmorillonites have low adsorption capacity for DON due to its poor planarity preventing it from entering into interfacial layer of montmorillonite.
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