donkeydesert13
donkeydesert13
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Ohafia, Abuja, Nigeria
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Aquatic birds found at the top of the trophic chain are exposed to xenobiotics present both in food and inhaled air. The aim of this study was to indicate and assess the routes and levels of exposure of aquatic birds to bisphenol A (BPA), 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP). The birds constituting the study material (Clangula hyemalis, Alca torda, Mergus merganser) originated from by-catches (winter 2014-2016) in the Southern Baltic. The studies show that the exposure of birds to phenol derivatives is determined by the specifics of a compound, the habitat area, trophic level and food consumed. BPA was characterized by the highest intestinal concentrations in all birds (6.6-1176.2 ng.g-1 dw). Higher concentrations of 4-t-OP were determined in the lungs of birds from the eastern part of the Southern Baltic (9.1-135.7 ng.g-1 dw) and in the intestines of birds from the western part ( less then 0.5-191.4 ng.g-1 dw). In the case of 4-NP, higher concentrations were found in the intestines of carnivorous species (64.9-524.5 ng.g-1 dw), and the lungs of benthos-eating species (39.4-399.7 ng.g-1 dw). The intestines that were most burdened with 4-NP were those of birds from the highest trophic level. Correlations between the concentrations of phenol derivatives in the blood and the intestines and lungs indicated that birds are exposed to the penetration of phenol derivatives through the digestive and respiratory tracts. BPA and 4-NP were characterized by the highest concentrations in the intestines and lungs, whereas 4-t-OP in blood (3.2-39.2 ng.cm-3), which may indicate the largest endocrine potential of this compound in birds. Significant differences in phenol derivatives concentrations in the intestines and lungs of birds from the western and eastern part of the Southern Baltic, shows that these tissues can be useful for assessing the contamination of the environment with EDCs.Solar energy is one of the most promising renewable energy sources to solve the energy crisis. BRD7389 cost Dust deposition on solar photovoltaic (PV) modules significantly reduces the power generation of PV power plants. In this paper, the motion characteristics of the gas phase and charging mechanism of dust particles and solar PV glass are investigated by means of the computational fluid dynamics-discrete element model (CFD-DEM) method. In addition, the mechanism and characteristics of dust deposition on a solar PV module as dominated by electrostatic force are discussed. The research results show that frequent collisions between dust particles and PV glass or between dust particles lead to charging. The dust deposition mechanism on a solar PV module is a gas-solid-electrical multi-directional coupling process. There is a great electrostatic field near the solar PV glass, causing charged dust particle deposition. The dust deposition density decreases when the air inlet velocity increases and when the tilt angle of the solar PV module or the number of particle collisions decreases. Different particle dynamics have different dust deposition ratios for different predominant deposition forces (such as the electrostatic force, van der Waals force, and gravity force). The research findings provide an important theoretical basis for dust deposition prevention and removal from solar PV modules.Northern China was simulated as the main contributor to global chlorofluorocarbon (CFCs) that slowed down the recovery of stratospheric ozone layer in most recent studies. An atmospheric campaign was carried out from June 2017 to April 2018 to register the concentrations of typical chlorofluorocarbons (CFCs) (i.e., CFC-11, CFC-12, CFC-113, and CFC-114) at the top of Mount Tai, northern China. The mixing ratios of CFC-11 CFC-12, CFC-113, and CFC-114 were 257, 577, 80, and 18 pptv, respectively. These values are similar to the reported data 10 years ago at Mount Tai. CFC concentrations correlated well with those of benzene (an anthropogenic tracer) and were not affected by either humidity, temperature, or solar radiation. However, CFC concentrations were considerably influenced by regional transport their backward trajectory and the PSCF (potential source contribution function) analysis suggested that higher concentrations (CFC-12, CFC-113 and CFC-114) were detected under the influence of air mass from the industrial regions in mid-eastern China and CFC-11 was through long-range transport from northwestern (i.e., from the higher atmosphere in western China) air masses. Overall, the findings of this study suggested that CFCs still have emissions in China, but no significant increase in recent years. Mid-eastern China might be responsible for the CFC emissions. The conclusions also highlight the need for the enforcement of effective control policies and the management of emissions, in order to avoid increasingly severe scenarios.UK government implemented national lockdown in response to COVID-19 on the 23-26 March 2020. As elsewhere in Europe and Internationally, associated restrictions initially limited individual mobility and workplace activity to essential services and travel, and significant air quality benefits were widely anticipated. Here, break-point/segment methods are applied to air pollutant time-series from the first half of 2020 to provide an independent estimate of the timings of discrete changes in NO, NO2, NOx, O3, PM10 and PM2.5 time-series from Automatic Urban Rural Network (AURN) monitoring stations across the UK. NO, NO2 and NOx all exhibit abrupt decreases at the time the UK locked down of (on average) 7.6 to 17 μg·m-3 (or 32 to 50%) at Urban Traffic stations and 4 to 5.7 μg·m-3 (or 26 to 46%) at Urban Background stations. However, after the initial abrupt reduction, gradual increases were then observed through lockdown. This suggests that the return of vehicles to the road during early lockdown has already offset much of the air quality improvement seen when locking down (provisional estimate 50 to 70% by 01 July). While locking down O3 increased (7 to 7.4 μg·m-3 or 14 to 17% at Urban stations) broadly in line with NO2 reductions, but later changes suggest significant non-lockdown contributions to O3 during the months that followed. Increases of similar magnitudes were observed for both PM10 (5.9 to 6.3 μg·m-3) and PM2.5 (3.9 to 5.0 μg·m-3) at both Rural and Urban stations alike, but the distribution of changes suggests the lockdown was not an obvious direct source of changes in levels of either of these species during this period, and that more complex contributions, e.g. from resuspension and secondary aerosol, may be more likely major drivers for these changes.

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