Work in wastewater treatment plants (WWTPs) can be associated with respiratory symptoms and diarrhea. The aim of this study was to obtain knowledge about WWTP workers' exposure to airborne bacteria and endotoxin, and the inflammatory potential (TIP) of their exposure, and to evaluate the risk posed by the exposure by 1) calculating a hazard index and relating the exposure to suggested occupational exposure limits (OELs), 2) estimating the potential deposition of bacteria in the airways, 3) relating it to the risk group classification of bacteria by the European Union, and 4) estimating the TIP of the personal exposure. A cohort of 14 workers were followed over one year. Bioaerosols were collected using personal and stationary samplers in a grid chamber house and an aeration tank area. Airborne bacteria were identified using (MALDI-TOF MS), and TIP of exposure was measured using HL-60 cells. A significant effect of season, work task, and person was found on the personal exposure. A hazard index based on exposure levels indicates that the risk caused by inhalation is low. In relation to suggested OELs, 14% and 34% of the personal exposure were exceeded for endotoxin (≥50 EU/m3) and bacteria (≥500 CFU/m3). At least 70% of the airborne bacteria in the grid chamber house and the aeration tank area could potentially deposit in the lower respiratory tract. From the personal samples, three of 131 bacterial species, Enterobacter cloacae, Staphylococcus aureus, and Yersinia enterocolitica are classified within Risk Group 2. Seven additional bacteria from the stationary samples belong to Risk Group 2. The bacterial species composition was affected significantly by season (p = 0.014) and by sampling type/area (p = 0.001). The TIP of WWTP workers' exposure was higher than of a reference sample, and the highest TIP was measured in autumn. TIP of personal exposure correlated with bacterial exposure. Based on the geometric average exposures to endotoxin (9.2 EU/m3) and bacteria (299 CFU/m3) and based on the calculated hazard index, the risk associated with exposure is low. However, since 43 of 106 exposure levels exceed suggested OELs, the TIP of exposure was elevated and associated with bacterial exposure, and WWTP workers were exposed to pathogenic bacteria, a continued focus on preventive measures is important. The identification of bacteria to species level in personal samples was necessary in the risk assessment, and measurement of the microbial composition made the source tracking possible.
Beijing experienced serious haze pollution from 24 November 2015 to 2 December 2015. To investigate the planetary boundary layer characteristics, especially turbulence characteristics, the authors analyzed the wind, temperature, humidity, and turbulence characteristics during heavily polluted weather by using the observational data of the 325-m meteorological tower in Beijing. The results indicate that the pollution was mainly caused by the easterly and southerly winds. There were negative correlations between wind speed, turbulent kinetic energy, friction velocity, and the PM2.5 concentration. During clean days, the wind speed greatly enhanced with height; however, during the period of heavy pollution, the wind speed changed a little from the near-surface layer to the top of the tower. In contrast, the spatial variability of TKE from the near-surface layer to the upper layer was not so obvious. The heavy haze pollution in this study was often characterized by the emergence of an inversion layer; therefore, the diurnal variation of the boundary layer temperature was very small. At the time of serious pollution, the relative humidity was near 100%. The diurnal variations of sensible heat flux and water vapor flux were significantly reduced when severe pollution occurred.
The Natural Heritage Site of the Coast of Yellow Sea-Bohai Gulf of China plays a prominent role in the conservation of global biodiversity. However, with the increase in the number of species inhabiting here, the problem of competition in the habitat space of species within the heritage site has gradually emerged, which has become an important bottleneck restricting the sustainable development of the heritage site. Therefore, this study selected the typical wetland wildlife in this area, red crowned crane (Grus japonensis) and Chinese water deer (Hydropotes inermis), as the study objects. This study used their continuous GPS tracking data to reveal the seasonal laws of habitat selection and suitability of two typical wetland species, and analyze their spatial competition and coexistence relationship. The study results showed that the distribution of home range of the crane and the deer in spring and summer was significantly larger than that in autumn and winter. The area of the sub and most suitable area of the deer in spring was larger than that of the crane. In autumn and winter, the area of the sub and most suitable areas for the deer was small, while the area of the most suitable area for the crane was more than 50 hm2. Except in spring, the two species kept a certain distance from each other in other seasons, and their habitat selection was stable. The optimal threshold range of the crane for D_ree variable was 0–202 m in spring and 0–1200 m in summer and autumn. The deer was affected by vegetation factors in the four seasons. The threshold range of D_ree variable in spring, autumn and winter was 0–80 m, the suitable vegetation height of the deer was 2.31–2.92 m. Finally, this study proposed a refined management pattern of habitat with multiple species coexist.
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