10 research outputs found
Identification of Viral Pathogen Diversity in Sewage Sludge by Metagenome Analysis
The large diversity of viruses that exist in human populations
are potentially excreted into sewage collection systems and concentrated
in sewage sludge. In the U.S., the primary fate of processed sewage
sludge (class B biosolids) is application to agricultural land as
a soil amendment. To characterize and understand infectious risks
associated with land application, and to describe the diversity of
viruses in human populations, shotgun viral metagenomics was applied
to 10 sewage sludge samples from 5 wastewater treatment plants throughout
the continental U.S, each serving between 100ā000 and 1ā000ā000
people. Nearly 330 million DNA sequences were produced and assembled,
and annotation resulted in identifying 43 (26 DNA, 17 RNA) different
types of human viruses in sewage sludge. Novel insights include the
high abundance of newly emerging viruses (e.g., <i>Coronavirus</i> HKU1, <i>Klassevirus</i>, and <i>Cosavirus</i>) the strong representation of respiratory viruses, and the relatively
minor abundance and occurrence of <i>Enteroviruses</i>.
Viral metagenome sequence annotations were reproducible and independent
PCR-based identification of selected viruses suggests that viral metagenomes
were a conservative estimate of the true viral occurrence and diversity.
These results represent the most complete description of human virus
diversity in any wastewater sample to date, provide engineers and
environmental scientists with critical information on important viral
agents and routes of infection from exposure to wastewater and sewage
sludge, and represent a significant leap forward in understanding
the pathogen content of class B biosolids
Indoor Emissions as a Primary Source of Airborne Allergenic Fungal Particles in Classrooms
This study quantifies the influence
of ventilation and indoor emissions
on concentrations and particle sizes of airborne indoor allergenic
fungal taxa and further examines geographical variability, each of
which may affect personal exposures to allergenic fungi. Quantitative
PCR and multiplexed DNA sequencing were employed to count and identify
allergenic fungal aerosol particles indoors and outdoors in seven
school classrooms in four different countries. Quantitative diversity
analysis was combined with building characterization and mass balance
modeling to apportion source contributions of indoor allergenic airborne
fungal particles. Mass balance calculations indicate that 70% of indoor
fungal aerosol particles and 80% of airborne allergenic fungal taxa
were associated with indoor emissions; on average, 81% of allergenic
fungi from indoor sources originated from occupant-generated emissions.
Principal coordinate analysis revealed geographical variations in
fungal communities among sites in China, Europe, and North America
(<i>p</i> < 0.05, analysis of similarity), demonstrating
that geography may also affect personal exposures to allergenic fungi.
Indoor emissions including those released with occupancy contribute
more substantially to allergenic fungal exposures in classrooms sampled
than do outdoor contributions from ventilation. The results suggest
that design and maintenance of buildings to control indoor emissions
may enable reduced indoor inhalation exposures to fungal allergens
Predicting Contaminant Adsorption in Black Carbon (Biochar)-Amended Soil for the Veterinary Antimicrobial Sulfamethazine
Commercial hardwood biochars ranging
in N<sub>2</sub> specific
surface area of 0.1ā427 m<sup>2</sup>Ā·g<sup>ā1</sup> were added to an agricultural soil at 0, 1, or 2% levels to determine
whether they would predictably reduce the pore water concentration
of sulfamethazine (SMT). The soil and biochar-soil mixtures were preweathered
under mild (2 d, 20 Ā°C) or more severe (28 d, 40 Ā°C) conditions
before spiking. The carbon-normalized biochar-water distribution coefficient
(<i>K</i><sub>BC</sub>) of the biochars varied by a factor
of up to 10<sup>4</sup>, depending on biochar properties and SMT concentration.
Except for the fast-pyrolysis biochar, <i>K</i><sub>BC</sub> greatly exceeded the soil organic carbonāwater distribution
coefficient <i>K</i><sub>OC</sub>. Sorption in the mixtures
increased as expected with biochar and dose. However, sorption was
dramatically overpredicted (by up to 10<sup>2.5</sup>) by the sum
of sorption to the individual components, indicating a strong weathering
effect even under the mild conditions. The soil-subtracted weathered
biochar-water isotherms were more linear, and the <i>K</i><sub>BC</sub> values approached or lay within the range of <i>K</i><sub>OC</sub> values reported for SMT in 19 soils. Biochars
both in intimate contact with soil and placed in a membrane bag suspended
in the solution showed reduced N<sub>2</sub>āB.E.T. surface
area after weathering, implicating fouling of the biochar surface
by humic substances transferred through water. The results indicate
that only highly surfaceous, carbonaceous biochars would be useful
for stabilizing soil contaminated with compounds such as SMT. They
also suggest that weathering may attenuate the contribution of native
(environmental) black carbon to sorption of such compounds in soils
and sediments
Relative abundances of bacteria in the indoor air, ventilation duct air, floor dust, and HVAC filter dust samples.
<p>Relative abundances of the 20 most common bacterial taxa in indoor air, ventilation duct air, HVAC filter dust, and floor dust. Indoor and ventilation duct air include PM<sub>10</sub> samples from indoor air when the room was occupied. Floor dust samples were sieved PM<sub>37</sub> floor dust and resuspended PM<sub>10</sub> floor dust taken after occupancy. HVAC filter dust represents samples from the filter of the building HVAC system that handled a variable mixture of outdoor air and indoor return air. Taxa are classified to the highest taxonomic level to which they could be confidently assigned. Error bars represent one standard error of the mean for nine indoor air PM<sub>10</sub> samples, four floor dust samples, and three HVAC duct samples. Groups shown represent 55% of floor dust, 83% of HVAC filter dust, 51% of indoor air taxa, and 46% of ventilation duct air taxa.</p
Airborne particulate matter, filter dust, and floor dust samples acquired and analyzed in this study.
<p>Airborne particulate matter, filter dust, and floor dust samples acquired and analyzed in this study.</p
The influence of floor dust resuspension and particle shedding on particle number concentrations of varying optical diameter.
<p>Plotted are the ratio of occupied indoor to simultaneous outdoor particle number concentrations for five size ranges from 0.3 Āµm to 10 Āµm under the following three conditions. Black bars represent the case of 30 people sitting on a carpeted floor that is covered with plastic sheeting (to prevent resuspension of floor dust). White bars represent one person walking on a carpeted floor covered with plastic sheeting. Gray bars represent one person walking on a carpeted floor (without plastic sheeting). Error bars indicate one standard error of the mean for replicate experiments. The experiment in which 30 people were sitting on a carpeted floor covered with plastic sheeting was conducted only once.</p
Enrichment of bacteria in airborne particulate matter and floor dust.
<p>Bacterial mass percentage (100Ćbacterial mass divided by total particle mass) in indoor air, outdoor air, and duct supply air samples and in the PM<sub>2.5</sub> and PM<sub>10</sub> size fraction of resuspended floor dust samples. Mass fractions were estimated assuming an average mass of 655 fg per bacterium <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034867#pone.0034867-Ilic1" target="_blank">[25]</a>. Box and whisker plots have the same interpretation as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034867#pone-0034867-g001" target="_blank">Figure 1</a>.</p
Additional file 2 of Lineage abundance estimation for SARS-CoV-2 in wastewater using transcriptome quantification techniques
Additional file 2. Review history
Additional file 1 of Lineage abundance estimation for SARS-CoV-2 in wastewater using transcriptome quantification techniques
Additional file 1. Includes all supplementary information, supplementary figures and supplementary tables