Microbiological and meteorological analysis of two Australian dust storms in April 2009

Dust is an important source of bioaerosols including bacteria. In this study, the microbiology and meteorology of specific dust storms in Australia were investigated. The samples were collected from two dust events in April 2009 that were characterised by intense cold fronts that entrained dust from the highly erodible and drought-stricken Mallee and Riverina regions of Victoria and central NSW. In the first storm, the dust travelled eastward over Canberra and Sydney, and in the second storm, the dust travelled east/southeastward over Canberra and Melbourne. Rain fell on both cities during the second dust storm. Dust and rain samples were collected, cultured, and the composition compared using polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). Multiple bands were evident on DGGE indicative of a diverse microflora, and identification of several bands confirmed the presence of multiple genera and species representing three phyla. Numerous bands represented Bacillus species, and these were present in multiple dust samples collected from both Canberra and Melbourne. Interestingly, the microflora present in rain samples collected in Canberra during the second dust storm was quite different and the DGGE banding patterns from these samples clustered separately to most dust samples collected at the same time. Identification of several DGGE bands and PCR products from these rain samples indicated the presence of Pseudomonas species. These results indicate that Australian dust and rain have a diverse microflora and highlights the contribution of dust events to the distribution of microbes in the environment.     

Wet and dry deposition patterns of plutonium in Daejeon, Korea

Plutonium in wet and dry deposition samples collected monthly at the Korea Institute of Nuclear Safety (KINS), Daejeon, Korea was determined during the period from January 2000 to August 2000. Monthly 239,240Pu deposition in Korea showed a maximum in the spring season (March to May), which was several times greater than that in Japan and corresponds to a seasonal cycle of soil dust fallout originating from the East Asian arid areas. The trajectory analysis of dust storms suggests that 239,240Pu deposition in Korea in spring is originating from plutonium-bearing surface soil particles from the East Asian arid areas. A significant part of the 239,240Pu deposition in spring in Korea is attributable to dry deposition.     

Indoor and outdoor PM2.5 and PM10 concentrations in the air during a dust storm

Asian dust storms (ADS) originating from the arid deserts of Mongolia and China are a well-known springtime meteorological phenomenon throughout East Asia. The ventilation systems in office utilize air from outside and therefore it is necessary to understand how these dust storms affect the concentrations of PM_2.5 and PM₁₀ in both the indoor and outdoor air. We measured dust storm pollution particles in an office building using a direct-reading instrument (PC-2 Quartz Crystal Microbalance, QCM) that measured particle size and concentration every 10 min for 1 h, three times a day. A three-fold increase in the concentrations of PM_2.5 and PM₁₀ in the indoor and outdoor air was recorded during the dust storms. After adjusting for other covariates, autoregression models indicated that PM_2.5 and PM₁₀ in the indoor air increased significantly (21.7 μg/m³ and 23.0 μg/m³ respectively) during dust storms. The ventilation systems in high-rise buildings utilize air from outside and therefore the indoor concentrations of fine and coarse particles in the air inside the buildings are significantly affected by outside air pollutants, especially during dust storms.     

Stenotrophomonas,Mycobacterium, and Streptomyces in home dust and air: associations with moldiness and other home/family characteristics

Respiratory illnesses have been linked to children's exposures to water‐damaged homes. Therefore, understanding the microbiome in water‐damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water‐damaged homes. We collected air and dust samples in twenty‐one low‐mold homes and twenty‐one high‐mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp., and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, that is, with higher floor surface moisture and higher concentrations of moisture‐related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria.     

INORGANIC CHEMICAL COMPOSITION OF AEROSOLS SETTLING IN HAMAD TOWN,BAHRAIN FOLLOWING DUST HAZE STORMS

The inorganic chemical composition of settling particles from 10 dust storms in Hamad Town, Bahrain has been determined. These storms occurred over a 3‐year period. Meteorological conditions during the storms were examined and the storms classified, according to their trajectories, into two types: (a) a low pressure system from the Mediteranean, which traveled east into the Gulf and caused periods of disturbed weather and causing of northwesterly winds; and (b) a low pressure over Pakistan causing dry north‐westerly wind, known locally as Al‐Barah. After this period, the low pressure system declined allowing the formation of south‐easterly winds known as the Kaus. The composition of the dust storms is montonic. The settling particles are relatively enriched in Ca ²⁺, K ⁺ and SO ^2? ₄ derived from local soil, and Cl ^? from the sea.     

Culture‐dependent diversity of boron‐tolerant bacteria from boron mine tailings pond and solid wastes

Boron is a vital micronutrient for the growth of plants and different organisms. However, boron may be toxic to living cells at high concentrations. Nevertheless, microorganisms can be grown in harsh conditions such as environments with higher boron concentrations. It is also known that boron‐tolerant microorganisms have significant biotechnological potentials. In this study, it is aimed to isolate microorganism from a boron containing place in K?rka, Eski?ehir using culture‐dependent methods. After extracting genomic DNAs, Amplified Ribosomal DNA Restriction Analysis (ARDRA) profiles were constructed with HaeIII, MspI, HinfI‐HpaII and AluI‐CfoI. Sequence analyses were performed by chain‐terminating method. Consensus sequences were completed and similarities were determined by RDP Release 11. According to ARDRA, 10 profiles and five different species such as Pseudomonas sp., Enterecoccus sp., Acinetobacter sp., Bacillus sp. and Halomonas sp. were identified.     

Stability of airborne microbes in the Louvre Museum over time

The microbial content of air has as yet been little described, despite its public health implications, and there remains a lack of environmental microbial data on airborne microflora in enclosed spaces. In this context, the aim of this study was to characterize the diversity and dynamics of airborne microorganisms in the Louvre Museum using high‐throughput molecular tools and to underline the microbial signature of indoor air in this human‐occupied environment. This microbial community was monitored for 6 month during occupied time. The quantitative results revealed variations in the concentrations of less than one logarithm, with average values of 10³ and 10⁴ Escherichia coli/Aspergillus fumigatus genome equivalent per m³ for bacteria and fungi, respectively. Our observations highlight the stability of the indoor airborne bacterial diversity over time, while the corresponding eukaryote community was less stable. Bacterial diversity characterized by pyrosequencing 454 showed high diversity dominated by the Proteobacteria which represented 51.1%, 46.9%, and 38.4% of sequences, for each of the three air samples sequenced. A common bacterial diversity was underlined, corresponding to 58.4% of the sequences. The core species were belonging mostly to the Proteobacteria and Actinobacteria, and to the genus Paracoccus spp., Acinetobacter sp., Pseudomonas sp., Enhydrobacter sp., Sphingomonas sp., Staphylococcus sp., and Streptococcus sp.     

Phylogenetic analysis of atmospheric halotolerant bacterial communities at high altitude in an Asian dust (KOSA) arrival region, Suzu City

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. However, the atmospheric microbial community has not been investigated at high altitude in the KOSA arrival area. In this study, to estimate the viability and diversity of atmospheric halotolerant bacteria, which are expected to resist to various environmental stresses as well as high salinities, bioaerosol samples were collected at 10 and 600 m above the ground within the KOSA arrival area, Suzu City, Japan, during KOSA events. During the sampling period, the particle numbers at 600 m were higher than those at 10 m, suggesting that large particles of aerosol fall from the high altitude of 600 m to the ground surface. The microorganisms in bioaerosol samples grew in media containing up to 15% NaCl concentrations demonstrating the viability of the halotolerant bacteria in bioaerosol samples. The PCR-DGGE analysis using 16S rDNA revealed that the bacterial species in NaCl-amended cultures were similar to the bacteria detected from the genomic DNA directly extracted from the bioaerosol samples. The 16S rDNA sequences of bacterial communities in bioaerosol samples were classified into 4 phylotypes belonging to the Bacilluscereus or Bacillussubtilis group. The bioaerosol samples collected at 600 m included 2 phylotypes belonging to B. subtilis, and one phylotype among all 4 phylotypes was identical between the samples at 10 and 600 m. In the atmosphere at 600 m, the halotolerant bacterial community was expected to remain viable, and the species composition was expected to include a few species of the genus Bacillus. During this investigation period, these atmospheric bacteria may have been vertically transported to the ground surface, where the long-range KOSA particle transport from China is frequently observed.     

Impact of physico‐chemical parameters on the microbial population and its nature in a major retting zone of Kerala

As part of an environmental abatement programme, through the application of bioremediation in the retting zones of Kerala, a microbiological survey was conducted during March 1999 in the Kadinamkulam kayal, a major retting zone in Kerala. Some selected physico‐chemical parameters were also analysed to assess the water quality in the context of retting activity. Comparatively low dissolved oxygen content coupled with high hydrogen sulphide observed at Stations 1 and 2 can be attributed to retting. Salinity distribution is of the mixohaline nature. Pseudomonas sp., E. coli and other coliform groups were found to be present in the area. Of these the most dominant was Pseudomonas sp. and hence its nature and plasmid profile were also studied. The study indicates an environmental degradation in the area, and the possibility of hotspots of pollution in the backwater biotopes in the State.     

Estimates of Asian dust deposition over the Asian region by using ADAM2 in 2007

The Asian Dust Aerosol Model 2 (ADAM2) with the MM5 meteorological model has been employed to estimate the dust concentration, and wet and dry depositions of dust in the Asian region for the year of 2007. It is found that the model simulates quite reasonably the dust (PM₁₀) concentrations both in the dust source region (100-110°E and 37-43°N) and the downstream region of Korea. The starting and ending times of most of dust events and their peak concentration occurring times are well simulated. The annual average dust (PM₁₀) concentration near the surface is found to be 171 μg m^− 3 over the dust source area, 39 μg m^− 3 over the Yellow Sea, 25 μg m^− 3 over the Korean peninsula and 17 μg m^− 3 over the East Sea. It is also found that the annual total deposition of dust is about 118.1 t km^− 2 (dry deposition, 101.4 t km^− 2; wet deposition, 16.7 t km^− 2) in the dust source region, 19.0 t km^− 2 (dry deposition, 7.8 t km^− 2; wet deposition, 11.2 t km^− 2) in the Yellow Sea, 12.6 t km^− 2 (dry deposition, 6.5 t km^− 2; wet deposition, 6.1 t km^− 2) in the Korean peninsula and 10.7 t km^− 2 (dry deposition, 2.1 t km^− 2; wet deposition, 8.6 t km^− 2) in the East Sea. Their ratios of wet deposition to total deposition of dust in the respective regions are 14%, 59%, 48% and 80%. This clearly indicates that the main dust removal mechanism from the atmosphere is dry deposition over the source region whereas wet deposition predominates in the downstream region of the sea. The estimated dust deposition could adversely impact the eco-environmental system in the downstream regions of the dust source region significantly.     

Microbiological consequences of indoor composting

Recycling of organic waste appeals to more and more people. The aim of this study was to evaluate the microbiological contamination around organic waste bins at three distances over a 12‐month period. Contamination near the customary trash of control households was evaluated at the beginning to ensure that there is no recruitment bias. Air samples using the MAS 100 impactor were carried out in 38 dwellings that do household waste composting and in 10 dwellings of controls. Collection of particles by CIP 10 rotating cup sampler and dust samples collected by electrostatic dust collector cloths were acquired in dwellings that do household waste composting. Samples were analyzed by culture and by real‐time quantitative PCR. Information about dwelling characteristics and inhabitant practices was obtained by a standardized questionnaire. The genera most often isolated were Penicillium, Aspergillus, Cladosporium and Streptomyces. Near the organic waste bins, bioaerosol samples showed an increase of Acarus siro (P = 0.001). Sedimented dust analyses highlighted an increase of A. siro, Wallemia sebi, Aspergillus versicolor, and Cladosporium sphaerospermum concentrations after a 12‐month survey compared to the beginning. Composting favors microorganism development over time, but does not seem to have an effect on the bioaerosol levels and the surface microbiota beyond 0.5 m from the waste bin.     

Indoor air quality assessment in dwellings with different ventilation strategies in Nunavik and impacts on bacterial and fungal microbiota

Indoor air quality is a major issue for public health, particularly in northern communities. In this extreme environment, adequate ventilation is crucial to provide a healthier indoor environment, especially in airtight dwellings. The main objective of the study is to assess the impact of ventilation systems and their optimization on microbial communities in bioaerosols and dust in 54 dwellings in Nunavik. Dwellings with three ventilation strategies (without mechanical ventilators, with heat recovery ventilators, and with energy recovery ventilators) were investigated before and after optimization of the ventilation systems. Indoor environmental conditions (temperature, relative humidity) and microbiological parameters (total bacteria, Aspergillus/Penicillium, endotoxin, and microbial biodiversity) were measured. Dust samples were collected in closed face cassettes with a polycarbonate filter using a micro-vacuum while a volume of 20 m³ of bioaerosols were collected on filters using a SASS3100 (airflow of 300 L/min). In bioaerosols, the median number of copies was 4.01 × 10³ copies/m³ of air for total bacteria and 1.45 × 10¹ copies/m³ for Aspergillus/Penicillium. Median concentrations were 5.13 × 10⁴ copies/mg of dust, 5.07 × 10¹ copies/mg, 9.98 EU/mg for total bacteria, Aspergillus/Penicillium and endotoxin concentrations, respectively. The main microorganisms were associated with human occupancy such as skin-related bacteria or yeasts, regardless of the type of ventilation.     

Studying the cellulolytic activity of microorganisms isolated from stained painted walls with reference to certain factors: a cross sectional study

Investigations of enzymatic activities amongst microbial species on stained painted walls are not common especially in the tropics. Meanwhile, an organism’s enzymatic activity is a key index of its biodegradation potential. We conducted a cross-sectional study to assess the cellulolytic profiles of microorganisms isolated from stained painted buildings. A total of eight microorganisms comprising one bacterium [Pseudomonas aeruginosa CH01 (KY511067.1)] and seven fungi [Meyerozyma guillermondii MB14B1 (LT615287.1), Meyerozyma caribbica CBS:5674 (KY104219.1), Aspergillus aculeatus A1.9 (EU833205.1), Aspergillus sp. SL2 (KC178662.1), Fusarium proliferatum2705 (EU272509.1), Cerrena sp. N10CC2a (FJ010208.1) and Candida tropicalis UZ31_13 (KM361510.1)] were utilized for the study. The results showed that all isolates possessed exoglucanase and endoglucanase activities ranging from 0.174 to 1.554 IU/ml and 0.062 to 2.120 IU/ml, respectively. Analysis of the interplay of organism cellulolytic activity at various environmental conditions showed that endoglucanase activity was optimal in Cerrena sp., while the highest exoglucanase activity was recorded in P. aeruginosa.     

Initial investigation of microbially influenced corrosion (MIC) in a low temperature water distribution system

The purpose of this study was to determine if microorganisms could be considered a significant contributor to distribution system corrosion where year-round water temperatures remain near zero degrees Celsius. Initial evidence indicates that a heterogeneous population of potentially corrosive microorganisms were present in untreated supply water, treated water and corrosion tubercles. This included sulfite-reducing bacteria (Clostridium species), sulfate-reducers; iron-reducing bacteria (Bacillus species, Clostridium sp., Escherichia coli, Enterobacter aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas cepecia, Pseudomonas fluorescens), sulfur-oxidizing bacteria (Thiobacillus thiooxidans, Thiobacillus thioparus), iron-precipitating bacteria (Leptothrix, Gallionella, Sphaerotilus), sulfate-reducing actinomycetes and iron-reducing fungi (Penicillium, Rhizopus, Aspergillus). Corrosion tubercles contained greater numbers of coliforms than did the untreated supply or treated water. The ability of corrosion tubercles to sustain a diverse population of direct and opportunistic pathogens, able to participate in the corrosion process, may be an unrealized vector in the transmission of certain waterborne diseases to potential risk groups. In addition, corrosion tubercles may serve as a habitat for certain taste and odor-producing actinomycetes and fungi in treated water supplies. The ecology of these microorganisms, their influence on the corrosion process and the potential health impact needs to be investigated further.     

Biocenosis of BAC(F)s used for groundwater treatment

The studies on the biocenosis of biologically active carbon filters (BAC(F)) used in treatment of Miocene water revealed the presence of protozoa of the group of flagellates and ciliates (Glaucoma sp., Opercularia sp.), saprophytic bacteria, phase I and II nitrifying bacteria, Fe(II) and Mn(II) oxidizing bacteria of the family Siderocapsaceae, Leptothrix ochracea and Pedomicrobium sp., as well as microscopic fungi. The stratification of biofilter colonisation by these microorganisms was found to be similar to that occurring in biofilters applied in sewage treatment. A hypothetical model of microbiological transformations in BAC(F)s, brought about by various physiological groups of microorganisms, is presented. It is shown that ozone pre-treatment of water dosed to the biofilter reduces the number of saprophytic bacteria and moulds in its upper layer, as well as Fe(II) oxidizing bacteria of the family Siderocapsaceae across the full section of the biofilter; it does not, however, influence the abundance of nitrifying phase I and II autotrophic bacteria and Mn(II) oxidizing bacteria of the family Siderocapsaceae. The abundance of microorganisms in the biofilter outflow is increased in comparison with that in untreated water; they do not, however, create a health hazard for human beings.     

Inflammatory potential in relation to the microbial content of settled dust samples collected from moisture‐damaged and reference schools: results of HITEA study

Aiming to identify factors causing the adverse health effects associated with moisture‐damaged indoor environments, we analyzed immunotoxicological potential of settled dust from moisture‐damaged and reference schools in relation to their microbiological composition. Mouse RAW264.7 macrophages were exposed to settled dust samples (n = 25) collected from moisture‐damaged and reference schools in Spain, the Netherlands, and Finland. After exposure, we analyzed production of inflammatory markers [nitric oxide (NO), tumor necrosis factor‐α (TNF‐)α, interleukin (IL)‐6, and macrophage inflammatory protein (MIP)2] as well as mitochondrial activity, viability, apoptosis, and cell cycle arrest. Furthermore, particle counts, concentration of selected microbial groups as well as chemical markers such as ergosterol, 3‐hydroxy fatty acids, muramic acid, endotoxins, and glucans were measured as markers of exposure. Dust from moisture‐damaged schools in Spain and the Netherlands induced stronger immunotoxicological responses compared to samples from reference schools; the responses to Finnish samples were generally lower with no difference between the schools. In multivariate analysis, IL‐6 and apoptosis responses were most strongly associated with moisture status of the school. The measured responses correlated with several microbial markers and numbers of particles, but the most important predictor of the immunotoxicological potential of settled dust was muramic acid concentration, a marker of Gram‐positive bacteria.     

Atmospheric metal and phosphorus concentrations, inputs, and their biogeochemical significances in the Japan/East Sea

Atmospheric metals and phosphorus over the southern Japan/East Sea were investigated in order to evaluate their sources, concentrations and inputs, and to identify their biogeochemical roles in this marginal sea. Aerosols were collected on the east coast of Korea from February 2002 to April 2003 (n = 101) as well as at a remote island (Ulleung) and on a ship from February 2002 to June 2003 (n = 13). The aerosols were analyzed for Al, Co, Cu, Ni, P, Pb and Zn. Simultaneous collections of aerosols at both coast and offshore were performed, and several high dust aerosols (Al > 5 μg m^− 3) were collected at both regions. At the coastal site, both dust mineral and pollutants were transported by westerly winds from the Asian continent, but local emissions were significant (e.g., Cu, Ni, P and Zn) as well during the summer monsoon (May-August). The experimental relationships between the coast and offshore sites were defined. From these relationships, it was possible to obtain the annually averaged atmospheric metal and P concentrations over the southern Japan/East Sea, which has increased by over 2 times for the last decade. Through the estimation of atmospheric metal and phosphorus fluxes and comparisons with inputs from the Tsushima Warm Current, the atmospheric pathway was found to be a significant source for Al, Pb and Zn.     

Associations between respiratory infections and bacterial microbiome in student dormitories in Northern China

Recent studies reveal that the microbial diversity and composition in the respiratory tract are related to the susceptibility, development, and progression of respiratory infections. Indoor microorganisms can transmit into the respiratory tract through breathing, but their role in infections is unclear. Here, we present the first association study between the indoor microbiome and respiratory infections. In total, 357 students living in 86 dormitory rooms in Shanxi University were randomly selected to survey symptoms of infections. Settled air dust was collected to characterize bacterial compositions by 16S rRNA sequencing. The overall microbial richness was not associated with respiratory infections, but microorganisms from specific phylogenetic classes showed various associations. Taxa richness and abundance of Actinobacteria were protectively associated with infections (P < .05). The abundance of several genera in Gammaproteobacteria, including Haemophilus, Klebsiella, Buttiauxella, and Raoultella, was positively associated with infections (P < .005). The role of these microorganisms was consistent with previous human microbiota studies. Building age was associated with the overall microbial composition variation in dormitories and negatively associated with three potential risk genera in Proteobacteria (P < .05). The weight of vacuum dust was positively associated with a protective genus, Micrococcus in Actinobacteria (P < .05).     

Impacts of regional development strategies on growth and equity of Korea: A multiregional CGE model

This paper is concerned with the assessment of major regional development strategies such as the three Coastal area development strategies (East Coast Development, South Coast Development, and West Coast Development) and the Seoul-Pusan development corridor strategy in terms of efficiency and equity. Multiregional Computable General Equilibrium for Korea is developed to capture the economic impact of regional investment expenditures, estimating the time-series influences of regional development alternatives on economic growth, inflation, welfare, income distribution, and interregional economic inequality for ten periods. In a sense that the main point of concern in the national development planning of Korea is with the question of improvement of national competitiveness with more equitable interregional income distribution, it is necessary to promote the West Coast region rather than the Seoul-Pusan development corridor. The West Coast regional development can lead to substantial gain in GDP and reduction in regional income disparity. In a multinational economic perspective, this regional development is expected to contribute to the economic cooperation of Northeast Asia and to enhancing the joint comparative advantages between China and Korea. However, it might worsen the income inequality in the long run. Received: September 1999/Accepted: September 2001     

Characterizing the bacterial communities in retail stores in the United States

The microorganisms present in retail environments have not been studied in detail despite the fact that these environments represent a potentially important location for exposure. In this study, HVAC filter dust samples in 13 US retail stores were collected and analyzed via pyrosequencing to characterize the indoor bacterial communities and to explore potential relationships between these communities and building and environmental parameters. Although retail stores contained a diverse bacterial community of 788 unique genera, over half of the nearly 118K sequences were attributed to the Proteobacteria phylum. Streptophyta, Bacillus, Corynebacterium, Pseudomonas, and Acinetobacter were the most prevalent genera detected. The recovered indoor airborne microbial community was statistically associated with both human oral and skin microbiota, indicating occupants are important contributors, despite a relatively low occupant density per unit volume in retail stores. Bacteria generally associated with outdoor environments were present in the indoor communities with no obvious association with air exchange rate, even when considering relative abundance. No significant association was observed between the indoor bacterial community recovered and store location, store type, or season. However, predictive functional gene profiling showed significant associations between the indoor community and season. The microbiome recovered from multiple samples collected months apart from the same building varied significantly indicating that caution is warranted when trying to characterize the bacterial community with a single sampling event.