Carbapenem-resistant
(CRE) represent a health threat, but effective control interventions remain unclear. Hospital wastewater sites are increasingly being highlighted as important potential ...reservoirs. We investigated a large
carbapenemase (KPC)-producing
outbreak and wider CRE incidence trends in the Central Manchester University Hospital NHS Foundation Trust (CMFT) (United Kingdom) over 8 years, to determine the impact of infection prevention and control measures. Bacteriology and patient administration data (2009 to 2017) were linked, and a subset of CMFT or regional hospital KPC-producing
isolates (
= 268) were sequenced. Control interventions followed international guidelines and included cohorting, rectal screening (
= 184,539 screens), environmental sampling, enhanced cleaning, and ward closure and plumbing replacement. Segmented regression of time trends for CRE detections was used to evaluate the impact of interventions on CRE incidence. Genomic analysis (
= 268 isolates) identified the spread of a KPC-producing
outbreak clone (strain A, sequence type 216 ST216;
= 125) among patients and in the environment, particularly on 2 cardiac wards (wards 3 and 4), despite control measures. ST216 strain A had caused an antecedent outbreak and shared its KPC plasmids with other
lineages and
species. CRE acquisition incidence declined after closure of wards 3 and 4 and plumbing replacement, suggesting an environmental contribution. However, ward 3/ward 4 wastewater sites were rapidly recolonized with CRE and patient CRE acquisitions recurred, albeit at lower rates. Patient relocation and plumbing replacement were associated with control of a clonal KPC-producing
outbreak; however, environmental contamination with CRE and patient CRE acquisitions recurred rapidly following this intervention. The large numbers of cases and the persistence of
in
, including pathogenic lineages, are of concern.
Refractory black carbon (rBC) aerosol loadings and mass size distributions have been quantified during the HIPPO campaign above the remote Pacific from 80N to 67S. Over 100 vertical profiles of rBC ...loadings, extending from ∼0.3 to ∼14 km were obtained with a Single‐Particle Soot Photometer (SP2) during a two‐week period in January 2009. The dataset provides a striking, and previously unobtainable, pole‐to‐pole snapshot of rBC mass loadings. rBC vertical concentration profiles reveal significant dependences on latitude, while associated rBC mass size distributions were highly uniform. The vertical profiles averaged in five latitude zones were compared to an ensemble of AEROCOM model fields. The model ensemble spread in each zone was over an order of magnitude, while the model average over‐predicted rBC concentrations overall by a factor five. The comparisons suggest that rBC removal in global models may need to be evaluated separately in different latitude regions and perhaps enhanced.
In situ measurements of the mass, mixing state, and optical size of individual black‐carbon (BC) particles in the fine mode (90–600 nm) have been made in fresh emissions from urban and biomass ...burning sources with an airborne single‐particle soot photometer. Contrasts between the two sources are significant and consistent. Urban BC tends to smaller sizes, fewer coated particles, thinner coatings, and less absorption per unit mass than biomass‐burning BC. This suggests that urban BC may have a longer lifetime in the atmosphere and a different impact on BC radiative forcing in the first indirect effect than biomass‐burning BC. These measurements bound the likely variability in the microphysical state of BC emissions from typical continental processes, and provide direct measurements of the size distribution and coating state of fine‐mode BC for use in constraining climate and aerosol models. These results highlight the need for the integration of source‐specific information into such models.
Black carbon (BC) is the dominant aerosol absorber of solar radiation in the atmosphere and is an important component of anthropogenic climate forcing. BC's role is strongly dependent on its physical ...state, which can influence the way that BC particles may act as ice and cloud nuclei, as well as the way they interact with solar radiation. In situ measurements made with a single‐particle soot photometer flown on a NASA high‐altitude research aircraft show the mass and size of individual BC particles in the tropics, as well as their propensity to be found mixed with additional materials. Mie theory was used to connect observed light scattering off BC particles to the optical effects of coatings on the particles. The observations indicate that as BC from ground‐based emission sources rises in altitude to the lower stratosphere, coatings on BC particles become both thicker and more prevalent, while BC mass mixing ratios decrease dramatically from their values near the ground. Coatings enhance light absorption by the ambient BC column by at least 30%. These results reveal the microphysical state of BC in the atmosphere while providing important constraints for models evaluating BC's role in climate change.
A single-particle soot photometer (SP2) was flown on a NASA WB-57F high-altitude research aircraft in November 2004 from Houston, Texas. The SP2 uses laser-induced incandescence to detect individual ...black carbon (BC) particles in an air sample in the mass range of approx.3-300 fg (approx.0.15-0.7 microns volume equivalent diameter). Scattered light is used to size the remaining non-BC aerosols in the range of approx.0.17-0.7 microns diameter. We present profiles of both aerosol types from the boundary layer to the lower stratosphere from two midlatitude flights. Results for total aerosol amounts in the size range detected by the SP2 are in good agreement with typical particle spectrometer measurements in the same region. All ambient incandescing particles were identified as BC because their incandescence properties matched those of laboratory-generated BC aerosol. Approximately 40% of these BC particles showed evidence of internal mixing (e.g., coating). Throughout profiles between 5 and 18.7 km, BC particles were less than a few percent of total aerosol number, and black carbon aerosol (BCA) mass mixing ratio showed a constant gradient with altitude above 5 km. SP2 data was compared to results from the ECHAM4/MADE and LmDzT-INCA global aerosol models. The comparison will help resolve the important systematic differences in model aerosol processes that determine BCA loadings. Further intercomparisons of models and measurements as presented here will improve the accuracy of the radiative forcing contribution from BCA.
Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical ...tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.
•Sources and particle sizes of biochars influenced biochar mineralization and stability.•Stability of biochar in soil is salient feature to evaluate its use as C sequestration tool.•Biochar processed ...into pellets and dust-sized had significant effect on its mineralization.•Site specific application is an effective use of biochar as a soil amendment.
Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g., particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal information on the potential effects of biochar particle sizes on their breakdowns by soil microorganism, so it is unknown if the particle size of biochar influences C mineralization rate and/or stability in soils. In order to evaluate the effect of different sources (BS) and particle sizes (BF) of biochar on C loss and/or stability in soils, an incubation study on C mineralization of different biochar sources and particle sizes was established using two soils (ST): Norfolk soil (fine loamy, kaolinitic, thermic, typic Kandiudults) and Coxville soil (fine loamy kaolinitic, thermic, Paleaquults). In separate incubation vessels, these soils were amended with one of two manure-based biochars (poultry litters, PL; swine solids, SS) or one of two lignocellulosic-based biochars (switchgrass, SG; pine chips, PC) which were processed into two particle sizes (dust, <0.42mm; pellet, >2mm). The amount of CO2 evolved varied significantly between soils (p⩽0.0001); particle sizes (p⩽0.0001) and the interactions of biochar source (p⩽0.001) and forms of biochars (p⩽0.0001) with soil types. Averaged across soils and sources of biochar, CO2-C evolved from dust-sized biochar (281mgkg−1) was significantly higher than pellet-sized biochar (226mgkg−1). Coxville soils with SS biochar produced the greatest average CO2-C of 428mgkg−1 and Norfolk soils with PC had the lowest CO2-C production (93mgkg−1). Measured rates of carbon mineralization also varied with soils and sources of biochar (Norfolk: PL>SS>SG⩾PC; Coxville: PC>SG>SS>PL). The average net CO2-C evolved from the Coxville soils (385mgkg−1) was about threefold more than the CO2-C evolved from the Norfolk soils (123mgkg−1). Our results suggest different particle sizes and sources of biochar as well as soil type influence biochar stability.
New value-added uses for solid municipal waste are needed for environmental and economic sustainability. Fortunately, value-added biochars can be produced from mixed solid waste, thereby addressing ...solid waste management issues, and enabling long-term carbon sequestration. We hypothesize that soil deficiencies can be remedied by the application of municipal waste-based biochars. Select municipal organic wastes (newspaper, cardboard, woodchips and landscaping residues) individually or in a 25% blend of all four waste streams were used as feedstocks of biochars. Three sets of pyrolysis temperatures (350, 500, and 750 °C) and 3 sets of pyrolysis residence time (2, 4 and 6 h) were used for biochar preparation.
The biochar yield was in the range of 21–62% across all feedstocks and pyrolysis conditions. We observed variations in key biochar properties such as pH, electrical conductivity, bulk density and surface area depending on the feedstocks and production conditions. Biochar increased soil pH and improved its electrical conductivity, aggregate stability, water retention and micronutrient contents. Similarly, leachate from the soil amended with biochar showed increased pH and electrical conductivity. Some elements such as Ca and Mg decreased while NO3-N increased in the leachates of soils incubated with biochars. Overall, solid waste-based biochar produced significant improvements to soil fertility parameters indicating that solid municipal wastes hold promising potential as feedstocks for manufacturing value-added biochars with varied physicochemical characteristics, allowing them to not only serve the needs for solid waste management and greenhouse gas mitigation, but also as a resource for improving the quality of depleted soils.
•Paper and wood waste can serve as feedstocks for the production of value-added biochars.•Biochars can alleviate economic and environmental problems associated with solid waste disposal.•Soils amended with solid organic waste derived biochars can improve soil in fertility.•Biochars prepared from solid municipal waste can also be used for soil-carbon sequestration.
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