Donaldsonhsu1892

The current global Severe Acute Respiratory Syndrome- Coronavirus-2 (SARS-CoV-2) epidemic has heightened calls for studies to evaluate respiratory exposure for wastewater treatment workers. In this global first study, we assess occupational health risks to wastewater treatment plant (WWTP) operators from inhalation of aerosolized SARS-CoV-2 using a Quantitative Microbiological Risk Assessment (QMRA) framework. The following considerations were used to develop the QMRA and assess the illness risks to workers a) the proportion of the population who are infected and thus responsible for shedding SARS-CoV-2 into raw wastewater; b) the concentration of SARS-CoV-2 in raw and treated wastewater; c) the volume of aerosolized water inhaled by a WWTP operator during work; d) humidity and temperature-dependent viability of coronaviruses in aerosolized waste water; e) estimation of the amount, frequency, and duration of exposure; and f) exposure doses. The variables were then fed into an exponential dose response model to estimate the risks in three scenarios representing low-grade, moderate and aggressive outbreaks. These scenarios were designed on the assumption of 0.03%, 0.3% and 3% of the wastewater-generating population being infected with SARS-CoV-2. In terms of averaged-out illness risk profiles, the individual illness risks for low grade, moderate and aggressive outbreak scenarios respectively are 0.036, 0.32 and 3.21 illness cases per 1000 exposed WWTP operators. Our study suggests that the risk of accidental occupational exposure to SARS-CoV-2 in raw wastewater, via inhalation at the WWTP environment, is negligible, particularly when less than 0.3% of the population served by the plant are actively infected.The aim of this study was to estimate the risk posed by imidacloprid (IMI) seed coating to passerine birds of the Pampa Region of Argentina using data specifically generated with the grayish baywing (Agelaioides badius). Median lethal dose (LD50) of the IMI-based formulation tested was 57.11 mg IMI/kg body weight (bw), with intoxication signs starting from 20.6 mg IMI/kg bw. The feed intake rate (FIR) was estimated experimentally as 4.895 g/day per bird, representing 12.43% of bw. It was calculated that the ingestion of 7-10% of the FIR as treated seeds would be enough to achieve the LD50 for sorghum, corn, sunflower, and alfalfa, whereas consumption of 31 and 54% of FIR was necessary for oat and wheat, respectively. Based on spill data values available in the literature, it was calculated that, for most crops, a baywing would have to forage an area of field corresponding to less than 60 m2 to obtain the number of seeds required to reach the LD50. It was also shown that this number of seeds is coherent with the amount of seeds ingested in a bout. In a pilot study, all grayish baywings fed with millet seeds treated with 3 g IMI/kg died within three to five days of exposure. In Tier I risk assessment, the trigger value was achieved for all crops except soybean and a weight-of-evidence risk assessment was performed. All lines of evidence examined are consistent with the view that grayish baywings, and probably other small farmland birds, are exposed to a risk of acute toxicity and mortality under both worst-case and mixed-ration exposure scenarios. The possible impacts on bird species calls for an urgent reconsideration of IMI seed coating practices currently approved in the Pampa Region of Argentina and the various parts of the world where this practice is still in use.Three-dimensional graphene aerogel materials used for treatment of oily wastewater with sophisticated composition remains a challenge due to volume shrinkage, resulting in single-function and low adsorption capacity. In this work, renewable Enteromorpha was introduced into the graphene aerogel via facile hydrothermal-freeze casting treatment, forming the compression, ultralight and amphiphilic adsorbent for oil spill cleanup and water pollution remediation. Meanwhile, further freeze casting avoids aerogel collapse for capillary tension during drying and produce more hierarchical pores. As for oil spill clean up, the Enteromorpha modified graphene aerogel (EGA) exhibits excellent adsorption capacity towards oil and organic solvents than pristine graphene aerogel (GA). Even after several cycles by compression and heat treatment, it still has a stable adsorption capacity for oil and organic solvents. The EGA also showed high ability to absorb water-soluble pollutants, such as dyes through hydrogen bonding and electrostatic reactions between dye molecules and aerogel. The facile strategy to fabricate the Enteromorpha-based amphiphilic EGA broadens the applications in water treatment through the high-value utilization of Enteromorpha.Determining stratigraphic markers of the Anthropocene is important for demarcating Global Stratotype Section and Point (GSSP). Heavy metals and persistent organic pollutants (POPs) are candidate geochemical markers of the Anthropocene, but no study has comprehensively evaluated temporal trends in these pollutants in sediment cores globally. 454 data points for 8 heavy metals and 8 POPs were compiled to reconstruct their temporal trends and evaluate their global consistency. The heavy metals did not increase rapidly in the 20th century, and their temporal trends were locally but not globally consistent, which are not suitable geochemical markers of the Anthropocene. POPs rapidly increased beginning in the mid-20th century but have declined in the past decade, and these data are more consistent globally. The time of the peak concentration and period of rapid increase for polychlorinated biphenyls (PCBs) occur near the boundary of the Anthropocene and are consistent globally. Forty-five percent of the studies evaluated used only 210Pb chronology for dating, which creates definite uncertainty in the analysis. In GSSP candidate sections, PCBs could be considered candidate markers of the Anthropocene.Waste activated sludge (WAS) has attracted considerable attention as an excellent material for P recovery from sewage. this website This study took concentrated phosphorus removal sludge as objective, and aimed at providing an effective route to promote the transformation of polyphosphate in sludge pellets to dissolved phosphate. After acid pH adjustment, total dissolved phosphate at pH 3.0 was 37.3-fold higher than that at natural pH. The P distribution results illustrated that acid pH accelerated the degradation of short chain polyphosphate into orthophosphate. Furthermore, cell staining results confirmed that the polyphosphate was sourced from the leakage of intracellular matters. Low field NMR and rheology properties analysis were adopted to illustrate that acid pH treatment further improved WAS dewatering performances. Accompanied with the reduction of heavy metals in WAS pellets, the acid pH treatment was also beneficial for WAS subsequent treatment or final disposal. Lastly, Fe3+ addition was proposed as favorable P recovery method, and spherical nanometric materials of FePO4 crystal was obtained accordingly.