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ABSTRACTDuring wastewater treatment, bioaerosols are generated and, can either remain in suspension for several hours or settle on surfaces and workers may be exposed. The presence of pathogens in the air could contribute to an increased frequency of gastrointestinal or respiratory illness amongst workers. Due to harsh winter conditions in Eastern Canada, many of the steps in the wastewater treatment process occur indoors, leading to a greater risk of significant occupational exposure especially if there is inadequate ventilation or a lack of personal protection. This work has used stationary sampling at various indoor wastewater treatment steps both in winter and summer. Bioaerosols were evaluated using both culture and molecular methods along with ventilation characterization. Endotoxins were quantified, as well as total cultivable and gram-negative bacteria and pathogen indicators using qPCR. This study highlights the presence of potential pathogens at all steps in the treatment process, which may represent a potential occupational hazard. Comparisons between summer and winter data suggest that water temperature is an important factor for microbial activity and suggest that increasing the rate of air changes per hour in summer would be beneficial to reduce the concentration of bioaerosols during this time of the year. The screening, grit/FOGs removal and biofiltration were the most bioaerosol-loaded sites. Based on strong correlations, we suggest the reconsideration of exposure limits in WWTPs. Workers should be encouraged to use personal respiratory protection to limit the risk of health problems, especially during long-term work.Implications:The work presented herein showcases significant correlations between concentrations of endotoxins, cultivable bacteria, gram-negative bacteria, and total bacteria by qPCR from air collected in indoor wastewater treatment plants. These correlations lead us to propose new limit of exposure values, revisited to fit the endotoxin exposure limits recommendations. The results can serve as guidelines for future proposals for air quality indicators.

ABSTRACTBiomethanization is a new technology used for green-waste valorization where organic waste is biodegraded by microbial communities under anaerobic conditions. The main product of this type of anaerobic digestion is a biogas used as an energy source. Moving and handling organic waste may lead to the emission of high concentrations of bioaerosols. High exposure levels are associated with adverse health effects amongst green environment workers. Fungal spores are suspected to play a role in many respiratory illnesses. There is a paucity of information related to the detailed fungal diversity in biomethanization facilities. The aim of this study was to provide an in-depth description of fungal bioaerosols in biomethanization work environments using a next-generation sequencing approach combined with real-time polymerase chain reaction (PCR). Two biomethanization facilities treating different wastes were visited during the sampling campaign (n = 16). Quantification of Penicillium/Aspergillusand Aspergillus fumigatusrevealed a greater exposure risk during summer for both facilities visited. Concentrations of Penicilliumand Aspergilluswere similar in all work areas in both biomethanization facilities. Taxonomy analyses showed that the type of waste treated affects the fungal diversity of aerosols emitted. Although eight classes were evenly distributed in all samples, Eurotiomycetes were more dominant in the first facility and Agaricomycetes were dominant in the second one. A large diversity profile was observed in bioaerosols from both facilities showing the presence of pathogenic fungi. The following fungi detected are known allergens and/or are opportunistic pathogens: Aspergillus, Malassezia, Emericella, Fusarium, Acremonium, and Candida. Daily exposure to these fungi may put workers at risk. The information from this study can be used as a reference for minimizing occupational exposure in future biomethanization facilities.Implications: Biomethanization is a new technology used for green-waste valorization where organic waste is biodegraded by microbial communities. Effective waste management is increasingly recognized as a strategic approach for achieving newly created regulations concerning the disposal of organic residues; therefore, an expansion of facilities is expected. Workers’ exposure to diverse fungal communities is certain, as fungi are ubiquitous and necessary in organic matter decomposition. Monitoring this occupational exposure is important in order to prevent workers’ health problems.

Potato virus Y(PVY) is a major cause of yield and quality loss in potato crops worldwide. Recently, populations of PVY strains have shifted dramatically toward recombinant strains such as PVYNTNand PVYN:O. A 2010 to 2016 survey of PVY strains in commercial fields of New Brunswick (NB), Canada, and five field trials tracking PVY spread in NB and Manitoba, were conducted to study the current status of PVY strains and their relative rates of spread. In NB, PVYOdropped from 82% of infections in 2010 to 14% in 2016, replaced mostly by PVYNTN(64%) and PVYN:O (22%).In field trials with Russet Burbank and Gold rush varieties, PVYNTNspread most effectively compared to PVYN:Oand PVYO. Strain-specific PVY spread varied with the potato variety, possibly due to selective PVYOresistance in Goldrush, mostly expressed at the plant-to-plant transmission level with little difference in transduction to tubers in infected plants. Relevance of in-field differences in spread of strains to changes in regional PVY populations, and potential mechanisms responsible, are discussed. El virus Y de la papa (PVY) es una causa importante de pérdida de rendimiento y calidad en los cultivos de papa en el mundo. Recientemente, las poblaciones de las variantes de PVY han girado dramáticamente hacia recombinantes, tales como el PVYNTNy PVYN:O. Se condujo un estudio de 2010 a 2016 de las variantes de PVY en campos comerciales de New Brunswick (NB), Canada, y cinco ensayos de campo, siguiendo la huella de la dispersión en NB y Manitoba, para estudiar el estatus actual de las variantes del PVY y sus niveles relativos de dispersión. En NB, PVYObajó de 82% de infecciones en 2010 a 14% en 2016, reemplazado mayormente por PVYNTN(64%) y PVYN:O(22%). En ensayos de campo con las variedades Russet Burbank y Goldrush, el PVYNTNse dispersó más efectivamente comparado con PVYN:Oy PVYO. La dispersión específica por variante varío con la variedad de papa, posiblemente debido a la resistencia selectiva al PVYOen Goldrush, mayormente expresada en el nivel de la transmisión de planta a planta, con poca diferencia en la transducción a tubérculos en plantas infectadas. Se discuten la relevancia de las diferencias en el campo en la dispersión de las variantes a cambios en las poblaciones regionales de PVY, y mecanismos potenciales responsables.

ABSTRACTThis study sought to fill the gap in information about the type and the concentration of bioaerosols present in the air of biomethanization facilities (BF). Evaluation of bioaerosol composition and concentration was achieved in two biomethanization facilities located in Eastern Canada, during summer and winter. In order to have a thorough understanding of the studied environment, the methodology combined culture of bacteria and molds, qualitiative polymerase chain reaction (qPCR) for specific microorganisms, endotoxin quantification, and next-generation sequencing (NGS) for bacterial diversity. Results revealed that workers in biomethanization facilities are exposed to bioaerosols and pathogenic microorganisms similar to those found in composting plants. However, human exposure levels to bioaerosols are lower in BF than in composting plants. Despite these differences, use of personal protective equipment is recommended to lower the risks of health problems.Implications: Biomethanization is a new technology used in eastern Canada for waste management. In the next few years, it is expected that there will be an expansion of facilities in response of tight governmental regulations. Workers in biomethanization facilities are exposed to various amounts of bioaerosols composed of some harmful microorganisms. Therefore, monitoring this occupational exposure could be an interesting tool for improving worker’s health.

In the 2014 and 2015 crop seasons, the efficacies of different types, rates and combinations of mineral oil and insecticide foliar sprays for reducing Potato virus Y(PVY) spread were tested in controlled field trials in New Brunswick (NB), Canada. Experimental plots were planted with certified PVY-free Goldrush, supplemented with known virus-infected seed to raise PVY inoculum to 2.3% and 3% at the beginning of the 2014 and 2015 seasons, respectively. Treatments consisted of mineral oil-only sprays at different application rates, insecticide-only sprays of differing numbers, and several combined mineral oil and insecticide spray regimes, all compared to a no-spray control treatment. PVY spread to 18% (2014) and 22% (2015) of initially virus-free plants in no-spray control plots, with significant reductions observed in PVY spread in several treatments. Greatest PVY reductions, as low as 4% (2014) and 12% (2015), were in combined mineral oil and insecticide spray treatments, followed by oil-only sprays; while insecticide-only sprays did not significantly reduce PVY spread. As well as measuring PVY spread to marked test plants and randomly collected post-harvest tuber sample from the plots, exhibited similar treatment pattern for PVY incidence. Multiple logistic regression modeling confirmed the relative efficacy of combined oil and insecticide sprays for reducing PVY spread, while accounting for variable inoculum and aphid factors. Modeling also highlighted the importance of planting low-PVY seed initially, and of early application of foliar sprays. Local best management practice recommendations for reduction of in-field PVY spread were discussed. En los ciclos de cultivo de 2014 y 2015, se probaron, en ensayos controlados de campo en New Brunswick, Canadá, las eficacias de diferentes tipos, dosis, y combinaciones de aceite mineral e insecticidas en aspersión foliar, para reducir la dispersión del virus Y de la papa (PVY). Los lotes experimentales se plantaron con semilla certificada libre de PVY, var. Goldrush, suplementada con semilla infectada de virus para aumentar el inóculo de PVY a 2.3% y 3% al principio de los ciclos de 2014 y 2015, respectivamente. Los tratamientos consistieron de aspersiones solamente con aceite mineral en diferentes dosis, o solamente de diferente número de insecticidas, y de varias combinaciones de regímenes de aspersiones de aceite mineral e insecticidas, todos comparados con un tratamiento testigo sin aspersiones. El PVY se dispersó al 18% (2014) y 22% (2015) de plantas inicialmente libres de virus en los lotes testigo sin aspersiones, con reducciones significativas observadas en la dispersión de PVY en varios tratamientos. Las reducciones mayores de PVY, de hasta 4% (2014) y 12% (2015), fueron en los tratamientos de aspersiones de combinaciones de aceite mineral e insecticida, seguidos de las hechas solamente con aceite, mientras que las de únicamente insecticida no redujeron significativamente la dispersión. Así como al medir la dispersión del PVY a plantas marcadas y colecta al azar de muestras de tubérculo en post-cosecha, se exhibieron patrones similares de tratamiento para la incidencia de PVY. Los modelos de regresión múltiple confirmaron la eficacia relativa de la aspersión con la combinación de aceite e insecticida para reducir la dispersión del PVY, mientras se contaba con los factores de las variables de inóculo y de áfidos. Al modelar, también resaltó la importancia de plantar inicialmente semilla baja en PVY, y de la aplicación temprana de aspersiones foliares. Se discutieron las mejores recomendaciones locales sobre prácticas de manejo para la reducción de la dispersión de PVY en el campo.

Published studies on household wastecollectors' exposure to airborne biologicalagents (bioaerosols) do not indicate highexposures to these agents. However, thesestudies did not consider several factors. Theobjective of this study was to characterize theexposure of waste collectors to bioaerosols andto propose solutions to control exposures tothese agents.Personal exposures of waste collectors tobioaerosols (total bacteria, endotoxins andmolds) were measured for seven types ofcollection during the summer, which representsthe worst conditions. The effect of truckcleaning was also evaluated. Meanconcentrations of bacteria were all in theorder of 103–104CFU/m3of air. Theintervention threshold was exceeded forendotoxins during the collection of compostonce every two weeks in the country. Meanconcentrations varied from 8.5 to 100 endotoxinunits per cubic meter of air (EU/m3). Measuredmean concentrations of molds were between 8,300and 98,170 CFU/m3of air. Also, the cleaningof an empty garbage truck does not improve thequality of the air. On the other hand, a dirtytruck is not a major source of bioaerosols.The sources of these bioaerosols are leachate,particularly if the waste in the truck is oforganic origin, as well as the garbage pailsthat contain this waste. Unnecessary exposuresto these sources should therefore be avoided. For bioaerosols, stringent personal hygienemeasures remain one of the best means ofprevention.

This study identified and quantified the main chemical compounds - the substances responsible for the disagreeable odors - and the bioaerosols emitted during the biological treatment of paper mill effluents. It also identified the characteristics of the process that effects the generation or diffusion of these substances. All treatment stages were evaluated. Measuring sites were located as closely as possible to the potential emission sources. Measurements were taken in the summer in 11 paper mills during a 2- to 3-day period in each mill. Chemical compounds were evaluated by direct-reading instruments; bioaerosols were sampled by impaction and counted. Sulfur compounds, emitted into the air when the effluent or the sludge is stirred, had the highest concentrations; their presence was attributable to such things as kraft-type paper pulp. Next in concentration were the carbon and nitrogen oxides, ammonia, and some organic acids, produced by the action of microorganisms. These acids are found mainly in the sludge environment. Terpenes, which come from wood, are present at various locations in paper mills. Odor perception thresholds for most of these substances are much lower than those established to protect the health of workers. Significant concentrations of total bacteria, total molds, and endotoxins were measured at several sites. Gram-negative bacteria were high at only one site, whereas the mold Aspergillus fumigatus was occasionally present at low concentration. No actinomycetes bacteria were detected. The highest concentrations were measured where there was water or dust aerosolization. Emissions are therefore controlled by controlling the operations that lead to the dispersion of water and particles into the air.

ABSTRACTDesigners and managers of recycling processing plants need to be informed about the inherent occupational health and safety risks; however, there are few studies in the literature describing these risks. Therefore, the objectives of this project were to document the biological, chemical, physical, and ergonomic risks in three household-waste recycling plants. Bioaerosols (molds and bacteria) were measured using the methodology recommended by the American Society for Testing and Materials (ASTM). Chemical contaminants and physical agents suspected of being present in this type of environment were measured using the standard methods of the Quebec Occupational Health and Safety Research Institute (IRSST). The ergonomic part of the study identified the work requirements and risk factors causing the workers' physical symptoms.In summer, the average concentrations of total bacteria were greater than the Scandinavian guideline of 10,000 colony forming units per cubic meter of air (CFU/m3) in the receiving areas in plants 1 and 3, in the sorting areas of the three plants, and in shipping in plants 1 and 3. When the average concentrations of Gram-negative bacteria were compared to the Scandinavian guideline of 1000 CFU/m3of air, only the sorting department in plant 2 in summer exceeded this value. Average indoor concentrations of molds that were statistically significantly greater than those measured in the upwind outdoor air were measured in all departments in plants 1 and 3, regardless of the season, and only in sorting in plant 2 during the summer. The only chemical contaminant measured at average concentrations greater than 50% of the Threshold Limit Values (TLVs) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH) was CO in the sorting departments in plants 1 and 2 during the winter. Noise exceeded the ACGIH TLV in plant 2. The workers' physical symptoms seem to be caused by the posture and effort required while remaining in a stationary position. Action must be focused on improving aspects such as work organization and personal protection and on informing citizens of the need for cleanliness of the material to be recycled.

AbstractBoth the processing of solid waste and the composting of organic matter generate airborne biological contaminants. For this type of environment, some authors have proposed Threshold Limit Values (TLV) of 10,000 Colony Forming Units per cubic meter (CFU/m3) of air for total bacteria, and 1,000 CFU/m3of air for Gram-negative bacteria. Endotoxins produced by Gram-negative bacteria can cause fever and respiratory problems. Diarrhea and gastrointestinal problems can also be caused by Gram-negative bacteria. Other researchers have found Aspergillus fumigatus, which is considered an opportunistic pathogenic fungus, in the nose and throat of people exposed to compost. The objectives of this study were to evaluate the microbiological content of indoor and outdoor air, to detect concentrations of total and Gram-negative bacteria exceeding their proposed TLV, and to suggest corrective measures based on the technical and scientific literature. Air sampling was carried out twice in one day using Andersen samplers. The culture media used were trypticase soya agar for total bacteria, MacConkey for Gram-negative bacteria, and Sabouraud dextrose agar for the fungi. In at least one sample from each work station, the air concentrations of total bacteria exceeded 10,000 CFU/m3. The air concentrations of Gram-negative bacteria were above 1,000 CFU/m3of air at six of the nine work stations. Indoor concentrations of fungi exceeded outdoor concentrations at eight of the nine work stations studied. To reduce exposure to biological contaminants, it is suggested that ventilation be modified in the separating area, and protective and hygienic measures be initiated at the other work stations.

Airborne microorganisms were isolated with a sampler in two types of swine confinement buildings (farrowing units and fattening units). Respirable (particles <5 µm) and total dust fractions were obtained. Samplings were repeated every 2 weeks for a total of 6 samplings per unit between January and April. The predominant microorganisms isolated were bacteria (up to 1.25×106 CFU/m3) with an important fraction in the respirable size range (up to 0.5×106 CFU/m3). Only small quantities of grain-negative bacteria, yeasts, and molds were found. Identification of the colonies isolated revealed a great diversity of microorganisms present in the air of the different buildings. Enterobacter agglomerans, Moraxella, Acinetobacter calcoaceticus, and Pseudomonas were the most frequently identified bacteria. Scopulariopsis, Aspergillus, Penicillium, and Candida were the most numerous fungi. Faenia rectivirgula, the causative agent of farmer's lung, was not a major contaminant. The results show some differences in airborne microbial contamination between farrowing and fattening units; the distinction, however, is not clear-cut and was observed only for the total bacteria. The level of airborne microbial contamination in swine units does not significantly vary as a function of the outside temperature. Some species of bacteria and fungi isolated in this study are known to induce extrinsic allergic alveolitis. Other fungi are known to be potentially pathogenic for man. The air of swine confinement buildings is highly contaminated with bacteria, yeasts, and molds at a level up to 1200 time higher than so-called “normal air.”

This study simultaneously measured levels ofCO2, CO, NO, NO2, and total particulates in three bus garages of a mass transit company, using standard methods. Statistically significant (p≈0.0000) multiple correlations (r=0.547 to r=0.805) were found between contaminants and predictors such as CO2 or type of garage. A net CO2 concentration of 400 ppm can therefore be proposed as an indicator of the maintenance of air quality in these garages. While the specific relationship between CO2 levels will vary as a function of operating conditions in specific garages, this approach can nevertheless serve as the basis of air-quality monitoring in other garages where diesel engines are in operation.

The American Conference of Governmental Industrial Hygienists (ACGIH) has issued a number of recommendations aimed at preventing abnormally high levels of bioaerosols. These include the elimination of stagnant water, microbial substrates, and microbial growth centres in ventilation systems, and the implementation of effective maintenance programmes. Disinfection tech niques (e.g., HEPA vacuuming, hypochlorite disinfection, and steam cleaning) are capable of eliminating microbial substrates and growth centres from ducts and other contaminated surfaces, but there is no information in the scientific literature on the optimum frequency of these operations. This study evaluated a number of corrective measures aimed at reducing aeromicrobial flora (bacte ria and saprophytic moulds). Samples of inside and outside air were taken at a laundry serving 30 hospitals. The outside air and that from 3 ventilation sys tems was sampled using a Burkard (Jet Spore) sampler, while an Andersen N-6 sampler was used to gather air samples at 6 workstations. Four 1-day sampling surveys were performed; in each case, samples were taken at least twice a day. In the first survey, carried out in June 1988, the contamination of outside air was found to differ significantly (p ≤ 0.05) from that of the air at some of the workstations, both qualitatively and quantitatively. The same workstations were re-evaluated in December 1988, 2 months after the ventilation system had been disinfected with hypochlorites and the operating conditions modi fied. No significant differences, either qualitative or quantitative, were observed between inside and outside air. The third sampling survey was undertaken in September 1989, 2 weeks after a specialized firm had per formed a complete disinfection of the system and ducts (HEPA vacuuming, steam cleaning, and disinfection with dilute hypochlorites). Visual inspection of the workplace and the ventilation system, now operating under normal con ditions, was also performed, in keeping with ACGIH recommendations. No significant difference was observed between inside and outside air. A 4th sur vey was conducted 8 months later, in May 1990, to verify the frequency of maintenance operations. Again, no significant differences were observed between inside and outside air. Ventilation systems should be disinfected before use, i.e., in the spring and autumn for air-conditioning units and heat ing units, respectively. The frequency of maintenance operations should be established on the basis of visual inspection.