Airborne Dust Samples Research Articles

Metagenomic insights into isolable bacterial communities and antimicrobial resistance in airborne dust from pig farms.

This study aims to investigate bacterial communities and antimicrobial resistance (AMR) in airborne dust from pig farms. Airborne dust, pig feces and feed were collected from nine pig farms in Thailand. Airborne dust samples were collected from upwind and downwind (25 meters from pig house), and inside (in the middle of the pig house) of the selected pig house. Pig feces and feed samples were individually collected from the pen floor and feed trough from the same pig house where airborne dust was collected. A direct total bacteria count on each sampling plate was conducted and averaged. The ESKAPE pathogens together with Escherichia coli, Salmonella, and Streptococcus were examined. A total of 163 bacterial isolates were collected and tested for MICs. Pooled bacteria from the inside airborne dust samples were analyzed using Metagenomic Sequencing. The highest bacterial concentration (1.9-11.2 × 103 CFU/m3) was found inside pig houses. Staphylococcus (n = 37) and Enterococcus (n = 36) were most frequent bacterial species. Salmonella (n = 3) were exclusively isolated from feed and feces. Target bacteria showed a variety of resistance phenotypes, and the same bacterial species with the same resistance phenotype were found in airborne dust, feed and fecal from each farm. Metagenomic Sequencing analysis revealed 1,652 bacterial species across all pig farms, of which the predominant bacterial phylum was Bacillota. One hundred fifty-nine AMR genes of 12 different antibiotic classes were identified, with aminoglycoside resistance genes (24%) being the most prevalent. A total of 251 different plasmids were discovered, and the same plasmid was detected in multiple farms. In conclusion, the phenotypic and metagenomic results demonstrated that airborne dust from pig farms contained a diverse array of bacterial species and genes encoding resistance to a range of clinically important antimicrobial agents, indicating the significant role in the spread of AMR bacterial pathogens with potential hazards to human health. Policy measurements to address AMR in airborne dust from livestock farms are mandatory.

Frequent Allergic Sensitization to Farmed Edible Insects in Exposed Employees

Exposure to insects used in pet food, scientific research, or live fish bait can cause an occupational allergy. The recent shift toward enhanced insect production for human consumption and animal feed will likely expose more employees. To investigate sensitization and symptoms in employees exposed to edible insects in Flanders. Fifteen insect-exposed employees were recruited and sensitization was explored by skin prick test, basophil activation test, and immunoblotting. Lung function, FeNO, histamine provocation, and sputum induction were studied. Airborne dust sampling was performed and proteins were studied by silver stain and immunoblotting. Sixty percent of employees self-reported upper respiratory tract symptoms related to insect exposure. Ten employees (71.4%) had a positive histamine provocation test concentration causing a 20% drop in FEV1 less than 8 mg/mL and four (26.7%) had FeNO levels above 25 ppb. Four employees (30.7%) had a positive skin prick test for at least one insect, and seven (58.3%) had a positive basophil activation test. In eight participants with insect sensitization, four (50%) had co-occurring house dust mite sensitization. Two participants had strong IgE binding to a 50-kDa migratory locust allergen, one to a 25-kDa mealworm allergen, and one to mealworm α-amylase. In one center, facility adjustment resulted in a substantial decrease in the inhalable dust fraction. Insect exposure leads to high levels of sensitization among employees. Most employees reported symptoms of the upper respiratory system, and two-thirds of employees had bronchial hyperreactivity. Prevention and health surveillance will be important in the developing insect-rearing industry.

Study of Air Polluted by Microparticles in the City of Apatity, Murmansk Region

Surface layers of apatite-nepheline ores mill tailings were analyzed. During the snowless period in2022, the dynamics of PM2.5 and PM10 dust concentrations in the atmosphere air of Apatity, Murmansk Region, was studied. Excess of MAC of sparingly solubles were detected. Mineralogical analysis of tailings and dust samples were carried out, the presence of nepheline and sodalite was detected, which confirms the involvement of tailing dumps of apatite-nepheline processing plants in air pollution. It was concluded that, in addition to the tailing dump, transport and other industrial sites have a significant impact on the atmosphere air, since airborne dust samples contain small particles of oxidized iron, plastic, glass, and metal scale. The role of green areas in buffer zones and within the boundaries of urban development was emphasized.

1 Comparison of Ni Speciation Using Methods of Sequential Leaching and Quantitative Mineralogy for Workplace Aerosol at a Stainless Steel Plant

Abstract Based on epidemiological records of workers at Ni operations, regulatory guidelines often target specific Ni compounds for setting exposure limits. Thus, reliable methods of Ni speciation in airborne dust samples are required for effective monitoring of workplace exposure. In this study, Ni speciation of dust collected from a stainless steel operation was performed using a variety of methods: Zatka sequential leaching (original and modified protocols), soluble and insoluble Ni as described in ISO 15202, and quantitative mineralogy (QEMSCAN). Mineral characterization was also performed on bulk material collected from selected work areas at the plant. The quantitative mineralogical analysis determined that the Ni dust is composed of oxidic Ni (Ni in chromite and trevorite, > 80 % of the Ni in most samples) and metallic Ni (Ni-Fe alloy), and the results were validated against chemical assays and alternate methods of mineral characterization (Electron Probe Microanalysis, EPMA). In contrast, the original Zatka method erroneously identified soluble Ni as a major Ni contributor, whereas the modified Zatka method identified sulfidic Ni. The mineralogy identified ambient dust and grain sizes and textures of individual Ni compounds as potential factors that can affect leaching selectivity. Improving methods of sequential leaching is important because the resolution of quantitative mineralogical techniques diminishes at < 3 µm (respirable dust fraction). We recommend that quantitative mineralogy be performed in parallel with methods of sequential leaching to provide a robust system of characterization.

Childhood lower respiratory tract infections linked to residential airborne bacterial and fungal microbiota

Residential microbial composition likely contributes to the development of lower respiratory tract infections (LRTI) among children, but the association is poorly understood. We aimed to study the relationship between the indoor airborne dust bacterial and fungal microbiota and childhood LRTI in Ibadan, Nigeria.Ninety-eight children under the age of five years hospitalized with LRTI were recruited and matched by age (±3 months), sex, and geographical location to 99 community-based controls without LRTI. Participants’ homes were visited and sampled over a 14-day period for airborne house dust using electrostatic dustfall collectors (EDC). In airborne dust samples, the composition of bacterial and fungal communities was characterized by a meta-barcoding approach using amplicons targeting simultaneously the bacterial 16S rRNA gene and the internal-transcribed-spacer (ITS) region-1 of fungi in association with the SILVA and UNITE database respectively.A 100-unit change in house dust bacterial, but not fungal, richness (OR 1.06; 95%CI 1.03–1.10) and a 1-unit change in Shannon diversity (OR 1.92; 95%CI 1.28–3.01) were both independently associated with childhood LRTI after adjusting for other indoor environmental risk factors. Beta-diversity analysis showed that bacterial (PERMANOVA p < 0.001, R2 = 0.036) and fungal (PERMANOVA p < 0.001, R2 = 0.028) community composition differed significantly between homes of cases and controls. Pair-wise differential abundance analysis using both DESEq2 and MaAsLin2 consistently identified the bacterial phyla Deinococcota (Benjamini-Hochberg (BH) adjusted p-value <0.001) and Bacteriodota (BH-adjusted p-value = 0.004) to be negatively associated with LRTI. Within the fungal microbiota, phylum Ascomycota abundance (BH adjusted p-value <0.001) was observed to be directly associated with LRTI, while Basidiomycota abundance (BH adjusted p-value <0.001) was negatively associated with LRTI.Our study suggests that early-life exposure to certain airborne bacterial and fungal communities is associated with LRTI among children under the age of five years.

Investigation of uterine microbiota in postpartum dairy cows and barn environment by quantitative PCR technique

The objective of this study was to investigate uterine microbiota in postpartum dairy cows and barn environment by quantitative PCR and to evaluate the correlation between the microbiota in the uterus and barn environment. The study was carried out in 2 seasons of the year: summer (June to August 2017) and winter (October 2017 to March 2018) on Holstein dairy cow farm, Okayama Livestock Research Institute, Japan. A total of 116 samples, including 68 uterine and fecal samples, were collected from 9 cows in summer and 8 cows in winter, at 1 and 2 months after calving. Additionally, 48 samples of barn environment including airborne dust, bedding, feed and water samples were collected 6 times throughout each season. The quantative PCR results showed significant differences (P &lt; 0.05) in the uterine and fecal microbiota of dairy cows at 1 and 2 months after calving. In summer, total bacteria at 2 months postpartum were higher than those at 1 month after calving, while total bacteria were the same in winter (P &gt; 0.05). Bacteroidetes and Firmicutes in uterus and feces between 1 and 2 months after calving were not significantly different in both summer and winter (P &gt; 0.05). The populations of Bacteroidetes, Firmicutes, and total bacteria were found to be highest in bedding compared to those in feed, airborne dust, and water from the barn environment (P &lt; 0.05). Bacteroidetes, Firmicutes and total bacteria in uterus were closely related with those in bedding in summer, however they had the negative correlation with the microbiota of barn environment in winter, especially with fecal microbiota.

Monitoring the Milk Composition, Milk Microbiota, and Blood Metabolites of Jersey Cows throughout a Lactation Period.

This study aimed to determine how milk composition, milk microbiota, and blood metabolites may change during the lactation period in Jersey cows. Milk and jugular blood samples were collected from eight healthy cows every other month from the beginning to the end of their lactation period. Samples of airborne dust were also collected to determine whether the cowshed microbiota could affect milk microbiota. Milk yield peaked in the first two months and gradually decreased as the lactation period progressed. Milk fat, protein, and solids-not-fat contents were low in the first month, and then increased during the middle and late lactation periods. In the first month, plasma non-esterified fatty acids (NEFA), haptoglobin (Hp), and aspartate transaminase (AST) levels were elevated, and high abundances of Burkholderiaceae and Oxalobacteraceae were observed in milk and airborne dust microbiota. The finding that contamination of the environmental microbiota in milk was coupled with elevated plasma NEFA, Hp, and AST levels indicated that impaired metabolic function during the early lactation period may increase the invasion of opportunistic bacteria. This study can affirm the importance of feeding and cowshed management and should provide a helpful addition to improving Jersey cow farming.

Composition of Culturable Microorganisms in Dusts Collected from Sport Facilities in Finland during the COVID-19 Pandemic.

Sport facilities represent extreme indoor environments due to intense cleaning and disinfection. The aim of this study was to describe the composition of the cultivated microbiota in dust samples collected in sport facilities during the COVID-19 pandemic. A dust sample is defined as the airborne dust sedimented on 0.02 m2 within 28 d. The results show that the microbial viable counts in samples of airborne dust (n = 9) collected from seven Finnish sport facilities during the pandemic contained a high proportion of pathogenic filamentous fungi and a low proportion of bacteria. The microbial viable counts were between 14 CFU and 189 CFU per dust sample. In seven samples from sport facilities, 20-85% of the microbial viable counts were fungi. Out of 123 fungal colonies, 47 colonies belonged to the potentially pathogenic sections of Aspergillus (Sections Fumigati, Nigri, and Flavi). Representatives of each section were identified as Aspergillus fumigatus, A. flavus, A. niger and A. tubingensis. Six colonies belonged to the genus Paecilomyces. In six samples of dust, a high proportion (50-100%) of the total fungal viable counts consisted of these potentially pathogenic fungi. A total of 70 isolates were considered less likely to be pathogenic, and were identified as Aspergillus section Nidulantes, Chaetomium cochliodes and Penicillium sp. In the rural (n = 2) and urban (n = 7) control dust samples, the microbial viable counts were >2000 CFU and between 44 CFU and 215 CFU, respectively, and consisted mainly of bacteria. The low proportion of bacteria and the high proportion of stress tolerant, potentially pathogenic fungi in the dust samples from sport facilities may reflect the influence of disinfection on microbial communities.

Airborne antibiotic resistome and human health risk in railway stations during COVID-19 pandemic

Antimicrobial resistance is recognized as one of the greatest public health concerns. It is becoming an increasingly threat during the COVID-19 pandemic due to increasing usage of antimicrobials, such as antibiotics and disinfectants, in healthcare facilities or public spaces. To explore the characteristics of airborne antibiotic resistome in public transport systems, we assessed distribution and health risks of airborne antibiotic resistome and microbiome in railway stations before and after the pandemic outbreak by culture-independent and culture-dependent metagenomic analysis. Results showed that the diversity of airborne antibiotic resistance genes (ARGs) decreased following the pandemic, while the relative abundance of core ARGs increased. A total of 159 horizontally acquired ARGs, predominantly confering resistance to macrolides and aminoglycosides, were identified in the airborne bacteria and dust samples. Meanwhile, the abundance of horizontally acquired ARGs hosted by pathogens increased during the pandemic. A bloom of clinically important antibiotic (tigecycline and meropenem) resistant bacteria was found following the pandemic outbreak. 251 high-quality metagenome-assembled genomes (MAGs) were recovered from 27 metagenomes, and 86 genera and 125 species were classified. Relative abundance of ARG-carrying MAGs, taxonomically assigned to genus of Bacillus, Pseudomonas, Acinetobacter, and Staphylococcus, was found increased during the pandemic. Bayesian source tracking estimated that human skin and anthropogenic activities were presumptive resistome sources for the public transit air. Moreover, risk assessment based on resistome and microbiome data revealed elevated airborne health risks during the pandemic.

Quality control of endotoxin measurement in dust samples/Qualitätskontrolle der Endotoxinmessung in Staubproben

Endotoxin activity determination is a common tool and a surrogate marker for bioaerosol assessment and is used at workplaces especially for this purpose. The reliability of the methods used for quantification in airborne dust samples is important for exposure estimation and thus for assessing the workplace situation. Within the scope of this study, the reproducibility of the endotoxin activity values determined with the two common methods, the LAL test and the rFC test, should be determined and compared. 21 water-based dust extracts from electrostatic dust collectors (EDC) were used for repeated endotoxin quantification using LAL and rFC test. As a result, twelve independent standard curves (0-50 EU/ml) were applied showing a median coefficient of variation (CV) of 9% for rFC and 12% for LAL test. The measured endotoxin activities of the samples could be reproduced within one test as well on three consecutive days. The CV of the 7- and 8-fold measured samples was below 20%. in 92% (LAL) and 93% (rFC) of the samples. Multiple measurements of the same sample showed that the results of LAL and rFC tests are highly reproducible. To eliminate interfering factors detected by recovery of spiked samples, dilutions of the samples are valuable methodological tools. This study demonstrates that quality-assured quantification of endotoxin activity is possible with both methods and is suitable for workplace measurements using the respective Standard Operation Procedure (SOP).

Development of analytical methods for the determination of 3-hydroxy fatty acids and muramic acid as bacterial markers in airborne particles and settled dust

Inhalation of airborne bacteria in indoor environments is known to be associated with respiratory diseases. Analytical methods for the determination of 3-hydroxy fatty acids (3-OHFAs) and muramic acid (MA) as chemical markers of gram-negative and gram-positive bacteria, respectively, were developed for airborne particle and dust samples in this study. 3-OHFAs as markers of endotoxin were released and esterified during the hydrolysis process under methanolic acid conditions, and their hydrolysates, i.e., 3-OHFA methyl esters, were cleaned up by solid-phase extraction using silica sorbent that provided more effective separation from interferents than polymeric sorbent through elution pattern. The SPE eluent was analyzed by GC-MS/MS measurement after the trimethylsilylation reaction. The recovery of the method ranged from 82.1 % to 103.2 %, with a limit of detection ranging from 0.5 to 1.1 ng/filter and good linearity (R2 > 0.991). For the analysis of MA, muramic acid methyl ester (MAME), a product formed during methanolic hydrolysis, was selected as a specific marker of peptidoglycan. It was the first proposed compound identified and confirmed with MS and MS/MS spectra using high-resolution measurement. In particular, the measurement of MAME providing 12.5 times greater sensitivity than MA with the application of the LC-MS/MS method is one of the notable findings of this study. The recovery by simple liquid extraction was 99.4 % following the removal of the hydrophobic matrix and neutralization with solvent reconstruction. The method displayed a LOD of 0.7 ng/filter and linearity (R2) of 0.997 through a simple pretreatment process. Both developed methods were applied and evaluated by determining 3-OHFAs and MA in airborne particles collected from multipurpose facilities and settled dust in the laboratory and office.

Measurement report: The Urmia playa as a source of airborne dust and ice-nucleating particles – Part 1: Correlation between soils and airborne samples

Abstract. The emergence of desiccated lake bed sediments and their exposure to wind erosion as a consequence of climate change and drought in arid and semiarid regions of the world poses a growing hazard. Airborne dust originating from such soils can create health and environmental issues due to their high salt content and the presence of toxic elements. The aim of the present study is twofold, namely to investigate the newly emerged playa surfaces of western Lake Urmia (LU) in Iran and their contribution to aerosol in the region by means of physicochemical, mineralogical, and elemental analyses and to study the ice nucleation (IN) activity of both surface-collected soil and airborne dust samples. The playa surfaces created by desiccation of LU on the western shores were mapped and sampled at 130 locations. Soil samples were subjected to physicochemical analyses, and their erodible fraction was determined. Based on these analyses, four highly erodible playa surfaces from the northwest to the south of LU were selected as sites for collection of dust by impaction and soil samples from the uppermost surface. Their particle physicochemical properties (size distribution, elemental and mineralogical composition) were compared with their IN activity determined by emulsion freezing experiments in a differential scanning calorimeter (DSC) in two suspension concentrations of 2 wt % and 5 wt %. The physicochemical soil properties differed significantly between the different playa surfaces, which affects their susceptibility to wind erosion. Sand sheets and sandy salt crusts were the most erodible playa surfaces due to their high sand fraction and low organic matter and clay content, favouring the presence of small aggregates. Mineralogical analyses document the prevalence of quartz, carbonates, and clay minerals, such as kaolinite, palygorskite, and chlorite in all of the samples. The predominant elements in the samples are Ca, Fe, Al, Si, and Na (and in some cases Ba, Sr, and Zn). The correlation between soil and dust samples based on mineralogical composition, elemental enrichment factors, and physicochemical properties confirm that the playa surfaces are the major contributors to dust in the region. IN activity with onset temperatures ranging from 245 to 250 K demonstrates the high potential of dust blown from Urmia playa surfaces to affect cloud properties and precipitation. Freezing onset temperatures and the fraction of heterogeneously frozen droplets in the emulsions reveal variations in IN activity depending on the mineralogical composition of the samples but which are also influenced by organic matter, salinity, and pH. Specifically, IN activity correlates positively with organic matter and clay minerals and negatively with pH, salinity, and (surprisingly) K-feldspar and quartz content. The high wind erodibility and dust production of the LU playa surfaces together with their high IN activity can play an important role in the climate of the region and thus needs careful monitoring and specific attention.

Chemické složení amfibolů v polétavém prachu z vybraných lokalit Brněnska

This study aimed to characterise the morphological and chemical properties of amphiboles from airborne dust samples collected from three localities in Brno and its surroundings. We analysed approximately 3 g of airborne dust particles from each sample. The mineralogical and morphological characteristics of the dust particles were examined by polarised-light microscopy and electron microprobe analysis. All studied airborne dust inorganic particles with length ≥ 5 μm show a ratio ≤ 3 : 1 or diameter of &gt; 3 μm and therefore do not be potentially dangerous to human health. We compared the chemical analyses of airborne needle-like dust particles (tremolite-actinolite, magnesiohornblende, pargasite; Si = 6.32–7.90 apfu; Mg/(Mg+Fe2+) = 0.34–0.84) with existing chemical composition amphiboles from possible source areas. The amphibole in airborne dust from the locality in the centre of the Brno town is completely dominated by actinolite and magnesiohornblende (Si = 6.48–7.56 apfu; Mg/(Mg+Fe2+) = 0.50–0.80) derived from basic and ultrabasic rocks of the Central Basic Belt of the Brno Massif. The granitoids of the Brno massif can be also a significant source of dust particles. Anthropogenic activity can explain a substantial proportion of amphibole from a relatively small body of amphibolites near Želešice (quarry in the Central Basic Belt of the Brno Massif) because these rocks are widely used as sanding material in the entire Brno agglomeration. The second locality of Rosice (west of Brno) is dominated by amphiboles (Si = 6.51–7.90 apfu; Mg/(Mg+Fe2+) = 0.55–0.84) from the west and northwest metamorphic units (Moravian and Moldanubicum). However, amphiboles from the rocks of the Brno massif are also presented. Amphiboles in the airborne dust from the Rajhradice (locality situated S from Brno) predominantly originated from the rocks of the Central Basic Belt of the Brno Massif (Si = 6.85–7.63 apfu; Mg/(Mg+Fe2+) = 0.50–0.78). Calcareous microfossils suggest that an essential component of the dust is also the material transported from the southeast, where dominated sediments of the Carpathian Flysch units and their foreland. Our results validate amphiboles as valuable minerals for identifying source areas from which dust has been derived and confirm dominant wind flows in the SE and NW directions.

Assessment of occupational and dietary exposures of feed handling workers to mycotoxins in rural areas from São Paulo, Brazil

In the current study, the occupational and dietary exposures of feed handling workers (N = 28) to aflatoxins (AFs), fumonisins (FBs), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEN), toxins T-2 and HT-2 were assessed for the first time in animal-producing farms and feed factories from São Paulo, Brazil. Mycotoxins in food (n = 244) and airborne dust (n = 27), as well as biomarkers in urine (n = 97) samples were determined by liquid chromatography coupled with tandem mass spectrometry. FBs were detected in all airborne dust samples, with concentrations ranging from 7.85 to 16,839 ng/m3. The mean probable daily intake (PDI) based on food data were 0.005, 0.769, 0.673 and 0.012 μg/kg of body weight (bw)/day for AFs, FBs, DON and ZEN, respectively. Mean PDI values obtained through urinary biomarkers were 0.29, 0.10, 0.50, 9.72 and 0.10 μg/kg body weight/day for AFB1, DON, OTA, FB1 and ZEN, respectively. The analyses based on urinary biomarkers revealed a potential health concern for OTA and FBs, although no potential health concern was observed with PDI calculated through food data. Results of this trial stress the need for preventive measures to avoid health risks of workers in Brazilian animal-producing farms and feed industries.

Assessment of localized and resuspended 137 Cs due to decontamination and demolition in the difficult-to-return zone of Tomioka town, Fukushima Prefecture.

As the next step that occurred more than one decade after the accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS), decontamination and demolition have been carried out in the Specified Reconstruction and Revitalization Base (SRRB) of the difficult-to-return zone around the FDNPS. However, the risk of internal exposure among workers due to airborne dust inhalation after building demolition operations has not been sufficiently evaluated. To evaluate the working environment and internal exposure risk due to inhalation in the SRRB of Tomioka town, Fukushima Prefecture, the cesium-137 (137 Cs) radioactivity levels in the airborne dust at building demolition sites were analyzed using gamma spectrometry. The 137 Cs radioactivity levels and resuspension factors of the airborne dust at the subject building sites in the difficult-to-return zone remained at high levels compared with those of the control, which was located in the evacuation order-lifted area in Tomioka town. However, the 137 Cs radioactivity levels did not increase significantly, despite demolition operations that used heavy machinery. In this case, no substantial increases in accident-derived 137 Cs levels due to decontamination and demolition in the SRRB of Tomioka town, Fukushima Prefecture, were observed in the airborne dust samples, which suggests that the 137 Cs radioactivity in the airborne dust is primarily associated with particles that are resuspended by localized winds accompanied by the transfer of construction vehicles as opposed to the decontamination and demolition operations. However, the internal exposure doses due to aspirating airborne dust containing 137 Cs were extremely low compared with the estimated annual effective doses of decontamination workers or the limits recommended by the Japanese government. Additionally, countermeasures such as wearing protective masks could help reduce the on-site inhalation of soil-derived radionuclides. Integr Environ Assess Manag 2022;18:1555-1563. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Detection of Khapra Beetle Environmental DNA Using Portable Technologies in Australian Biosecurity.

Khapra beetle, Trogoderma granarium Everts, 1898, is a serious pest of stored grain products globally. Environmental DNA (eDNA)-based methods offer sensitive detection tools used to inform biosecurity officers on the presence of high-risk pests. This study tested laboratory and portable molecular technologies to detect khapra beetle environmental DNA extracted from dust samples collected during biosecurity responses (Tuggeranong and Fyshwick) to khapra beetle incursions in Australia. Airborne and floor dust samples were collected opportunistically using handheld vacuum cleaners and eDNA was extracted using either field or laboratory-based extraction methods and analyzed using laboratory benchtop real time PCR machines and portable machines with two TaqMan and one LAMP-based assay. We successfully collected, extracted, and amplified khapra beetle eDNA from dust samples by qPCR, but failed to amplify T. granarium eDNA using LAMP. The Laboratory qPCR machine showed significantly higher mean Ct values (p < 0.001) and significantly higher positive detections for both assays (p < 0.001) compared to the portable thermocycler. DNA yield was significantly higher in samples extracted using laboratory-based kits compared to field kits (p < 0.001) for both vacuumed and airborne samples (Mean DNA ± S.D. = 5.52 ± 4.45 and 4.77 ± 1.68 ng/μL, respectively), compared to field kits, (1.75 ± 1.17 and 1.36± 1.29 ng/μL for vacuumed and airborne samples, respectively). There were no significant differences in DNA yield between collection methods or differences in amplification associated to extraction or collection methods in either platform tested in this study. Portable technologies tested in this study (Franklin™ Real Time Thermocycler and Genie III) accurately amplified all tissue derived DNA during assay optimisation and field testing, highlighting the capacity of these technologies to complement biosecurity in confirming specimen ID. There was a high incidence of positive detections in field negative controls (Tuggeranong = 12.3 % and Fyshwick = 50 %), mostly attributed to the use of contaminated vacuum cleaners. We discuss suitable methods to minimize sample cross-contamination, the potential of portable molecular technologies as tools for biosecurity applications, and the suitability of eDNA-based molecular detection methods to complement global trade biosecurity for one of the most invasive and important grain pests worldwide.

Comparison of quantitative mineralogy and sequential leaching for characterization of Ni in workplace dust collected at a stainless steel operation

Based on epidemiological records of workers at Ni operations, regulatory guidelines commonly target specific Ni compounds for setting exposure limits. Thus, reliable methods of Ni speciation in airborne dust samples are required for effective monitoring of workplace exposure. Zatka sequential leaching has been routinely performed industry-wide since the 1990s for characterization of Ni in dust samples; however, limitations related to leaching kinetics have been identified, and optimization of the methodology is required to improve accuracy of data. In this study, Ni characterization of dust collected from a stainless steel operation was performed using Zatka sequential leaching (original and modified protocols) and quantitative mineralogy (QEMSCAN), a method novel to the field of industrial hygiene. Mineral analysis was also performed on bulk material collected from selected work areas at the plant. The results are compared with the objective of identifying opportunities to optimize the methods for characterizing dust that is unique to stainless steel manufacturing. The quantitative mineralogical analysis determined that the Ni dust is composed of oxidic Ni (chromite and trevorite, >80% of the Ni in most samples) and metallic Ni (Ni-Fe alloy), and the results were validated against chemical assays and alternate methods of mineral characterization. In contrast, the original Zatka method erroneously identified soluble Ni as a major Ni contributor, whereas the modified Zatka method identified sulfidic Ni. The mineralogy identified Ni-barren dust and grain sizes and liberation of individual Ni compounds as potential factors that can affect leaching selectivity. Clearly, for any sequential leaching method to be useful for these workplaces, they should be optimized by including reference materials that are representative of Ni substances present at stainless steel operations (chromite, trevorite, and Ni-Fe alloy). Improving methods of sequential leaching is important because the resolution of quantitative mineralogical techniques diminishes at <3 μm (respirable dust fraction). We recommend that quantitative mineralogy be performed in parallel with methods of sequential leaching to provide a robust system of characterization.

Bioaerosol Exposure and in vitro Activation of Toll-like Receptors in a Norwegian Waste Sorting Plant

BackgroundThe global shift toward greener societies demands new technologies and work operations in the waste-management sector. However, progressive industrial methods do not necessarily consider workers’ health. This study characterized workers' exposure to bioaerosols and investigated the bioaerosols’ potential to engage the immune system in vitro. MethodsFull shift personal aerosol sampling was conducted over three consecutive days. Dust load was analyzed by gravimetry, fungal and actinobacterial spores were analyzed by scanning electron microscopy, and endotoxin by limulus amebocyte lysate (LAL) assay. In vitro exposure of HEK cells to airborne dust samples was used to investigate the potential of inducing an inflammatory reaction. ResultsThe total dust exposure level exceeded the recommended occupational exposure limit (OEL) of 5.0 mg/m3 in 3 out of 15 samples. The inhalable endotoxin level exceeded the recommended exposure level by a 7-fold, whereas the fungal spore level exceeded the recommended exposure level by an 11-fold. Actinobacterial spores were identified in 8 out of 14 samples. In vitro experiments revealed significant TLR2 activation in 9 out of 14 samples vs. significant TLR4 activation in all samples. ConclusionThe present study showed that the dust samples contained potentially health-impairing endotoxin, fungi, and actinobacterial levels. Furthermore, the sampled dust contained microbial components capable of inducing TLR activation and thus have the potential to evoke an inflammatory response in exposed individuals.

Mineralogical, geochemical, and textural characteristics of soil and airborne samples during dust storms in Khuzestan, southwest Iran

Dust storms are frequent phenomena in Khuzestan Province, southwest Iran, leading to environmental hazards and deleterious impacts on human health. This work analyzes mineralogic and geochemical characteristics of dust sediments at the source regions and in deposition areas in southwest Iran during three dust-storm events in winter and spring 2018. Twenty soil and airborne dust samples were collected and analyzed for compositions of dust at different distances from the source regions in Iraq and southwest Iran, aiming to assess the source characterization and possible mixing processes in the atmosphere. The grain size distributions were also analyzed at specific sites. The results show that about 50 % of the volume size distribution corresponds to particle sizes of above 20 μm, indicating local/regional dust storms of coarse to giant particles. XRD analysis indicates that calcite is the dominant mineral in all the samples, with a high quartz and dolomite fraction. The most abundant major compounds are SiO2 and CaO, while Cl, Ba, Sr, Pb, Ni, Zn, Cr, V are the main trace elements. The enrichment factor (EF) analysis showed that apart from Th, Nb, Ce, and V, all the other elements (Pb, Zn, Cr, etc.) have an anthropogenic origin or represent high amounts of pollutant contamination. High levels of elemental enrichment are attributable to intensive pollution in Khuzestan Province and at sampling sites due to fossil-fuel combustion, gas and petroleum drilling activities. Moreover, based on the geo-accumulation index (Igeo), all samples are found to be contaminated by heavy metals due to prior war-related materiel, oil and gas extraction, and emissions from polluting industries.

Mycotoxins Exposure of French Grain Elevator Workers: Biomonitoring and Airborne Measurements.

It is now recognized that additional exposure to mycotoxins may occur through inhalation of contaminated dust at a workplace. The aim of this study was to characterize the multi-mycotoxin exposure of French grain elevator workers using biomonitoring and airborne measurements. Eighteen workers participated in the study. Personal airborne dust samples were analyzed for their mycotoxin concentrations. Workers provided multiple urine samples including pre-shift, post-shift and first morning urine samples or 24 h urine samples. Mycotoxin urinary biomarkers (aflatoxin B1, aflatoxin M1, ochratoxin A, ochratoxin α, deoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, fumonisin B1, HT-2 toxin and T-2 toxin) were measured using a liquid chromatography–high-resolution mass spectrometry method. Grain elevator workers were highly exposed to organic airborne dust (median 4.92 mg.m−3). DON, ZEN and FB1 were frequent contaminants in 54, 76 and 72% of air samples, respectively. The mycotoxin biomarkers quantified were DON (98%), ZEN (99%), α-ZEL (52%), β-ZEL (33%), OTA (76%), T-2 (4%) and HT-2 (4%). DON elimination profiles showed highest concentrations in samples collected after the end of the work shift and the urinary DON concentrations were significantly higher in post-shift than in pre-shift-samples (9.9 and 22.1 µg/L, respectively). ZEN and its metabolites concentrations did not vary according to the sampling time. However, the levels of α-/β-ZEL were consistent with an additional occupational exposure. These data provide valuable information on grain worker exposure to mycotoxins. They also highlight the usefulness of multi-mycotoxin methods in assessing external and internal exposures, which shed light on the extent and pathways of exposure occurring in occupational settings.