Factors affecting vegetable growers' exposure to fungal bioaerosols and airborne dust

Occupational health and safety in cannabis production: an Australian perspective

The legal Australian cannabis industry has been rapidly expanding due to increased awareness of the plant's therapeutic potential, as well its diverse range of applications including biofuel, textiles, building materials, food, nutritional supplement, and animal feed. The objective of this paper is to describe the current landscape of the commercial Australian cannabis industry, summarise occupational health and safety (OHS) hazards in cannabis-related working environments, and provide suggestions for safeguarding worker health and well-being in this emerging industry. A comprehensive search of peer-reviewed and grey literature published between 1900 and 2017 was undertaken to identify case studies and original epidemiological research on OHS hazards associated with the cannabis cultivation and the manufacture of cannabis-based products. The review found that the majority of OHS studies were undertaken in the hemp textile industry during the late twentieth century, with a small number of articles published from a variety of occupational environments including forensic laboratories and recreational marijuana farms. Cannabis harvesting and initial processing is labour intensive, and presents a physical hazard Depending on the operation, workers may also be exposed to a variety of biological, chemical, and physical hazards including: organic dusts, bioaerosols, pollen/allergens, volatile organic compounds, psychoactive substances (tetrahydrocannabinol [THC])), noise, and ultraviolet radiation. Little research has been undertaken on the exposure to inhalable organic dust and other bioaerosols during the commercial cultivation and manufacture of cannabis-based products. Furthermore, there is an absence of Australian-based research and OHS guidance materials to help professionals develop risk management strategies in this evolving industry. It is recommended that: Investigation into the toxicological properties of cannabis dusts, specifically in relation to potential occupational exposures during cultivation and manufacture, should be a priority. The interim adoption of the respirable cotton dust exposure standard of 0.2 mg/m3 for workplace exposure in hemp facilities until a cannabis workplace exposure standard is developed, and that exposure to medicinal cannabis containing THC are kept as low as reasonably practicable. An industry partnership be established for the development of an Australian health and safety guideline for the production of medicinal cannabis and hemp. A classification to meet the requirements of the Global Harmonization Scheme should be undertaken to ensure consistency in the use of safety and risk phrases in cannabis-related industries.

Exposure to airborne endotoxin in Italian greenhouses: environmental analyses

The peculiar characteristics of the greenhouses as confined spaces, microclimate and poor air exchange with the outside environment, encourage the development of a large number of biological agents. Endotoxin, is probably a major causative agent of occupational health problems. The objective of this study was to measure the concentrations of airborne endotoxin in greenhouses with different cultures. The influence of microclimate was studied in correlation with endotoxin levels and type of cultured vegetables. The data indicate that workers employed greenhouses are exposed to low levels of inhalable endotoxins; endotoxin concentrations do not correlate with the temperature and relative humidity values. A strong correlation between the leaf size and endotoxin concentration was observed. The mean concentration of endotoxins in the air of greenhouses is relatively low, however, there could be peaks of exposure during harvesting and eradication of broadleaf plants.

Prevalence of toxigenic Penicillium species associated with poultry house in Telangana, India

The prevalence of mycotoxigenic Penicillium species in poultry houses of Telangana, India, was studied during 4 seasons between June 2009 and May 2010. Fungi belonging to 13 genera, including Penicillium, comprising 43 species were collected using petri plates. Fourteen Penicillium species demonstrated varying degrees of mycotoxigenicity. Chemical and chromatographic analysis of the different poultry feed samples revealed 8 different mycotoxins with ochratoxin A (OTA) predominating. The mean contamination rate of OTA was 38%. OTA quantities ranged between 5.78 and 6.73 µg/kg^-1, 10.13 and 14.23 µg/kg^-1, and 12.33 and 15.20 µg/kg^-1 in starter, broiler, and layer feeds, respectively. Statistically significant positive correlation between prevalence of Penicillium species and the monsoon, autumn, and spring seasons and negative correlation between prevalence and the autumn, spring, and summer seasons were observed. These findings may serve as risk exposure indicators and contribute toward the initiation of a sustainable control program.

Occupational exposure levels of bioaerosol components are associated with serum levels of the acute phase protein Serum Amyloid A in greenhouse workers

BACKGROUND

Occupational exposure to particles may be associated with increased inflammation of the airways. Animal experiments suggest that inhaled particles also induce a pulmonary acute phase response, leading to systemic circulation of acute phase proteins. Greenhouse workers are exposed to elevated levels of bioaerosols. The objective of this study is to assess whether greenhouse workers personal exposure to bioaerosol components was associated with serum levels of the acute phase proteins Serum Amyloid A (SAA) and C-reactive protein (CRP).

METHODS

SAA and CRP levels were determined in serum sampled repeatedly from 33 greenhouse workers. Blood was drawn repeatedly on Mondays and Thursdays during work weeks. Acute phase protein levels were compared to levels in a comparison group of 42 people and related to individual exposure levels to endotoxin, dust, bacteria, fungi and β-glucan.

RESULTS

Serum levels of SAA and CRP were not significantly different in greenhouse workers and a reference group, or on the two work days. In a mixed model, SAA levels were positively associated with endotoxin exposure levels (p = 0.0007). Results for fungi were not clear. CRP levels were positively associated with endotoxin exposures (p = 0.022). Furthermore, when workers were categorized into three groups based on SAA and CRP serum levels endotoxin exposure was highest in the group with the highest SAA levels and in the group with middle and highest CRP levels. SAA and CRP levels were elevated in workers with asthma.

CONCLUSION

Greenhouse workers did not have elevated serum levels of SAA and CRP compared to a reference group. However, occupational exposure to endotoxin was positively associated with serum levels of the acute phase proteins SAA and CRP. Preventive measures to reduce endotoxin exposure may be beneficial.

Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity

Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%-92% and temperature increased to 29-30 °C. S. aureus survived the best on filter materials with 40%-200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48-72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

Field evaluation of personal sampling methods for multiple bioaerosols

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

Detection of airborne bacteria in a duck production facility with two different personal air sampling devices for an exposure assessment

Prevalent airborne microorganisms are not well characterized in industrial animal production buildings with respect to their quantity or quality. To investigate the work-related microbial exposure, personal bioaerosol sampling during the whole working day is recommended. Therefore, bioaerosol sampling in a duck hatchery and a duck house with two personal air sampling devices, a filter-based PGP and a NIOSH particle size separator, was performed. Subsequent, quantitative and qualitative analyses were carried out with" culture independent methods. Total cell concentrations (TCC) determined via fluorescence microscopy showed no difference between the two devices. In average, 8 × 10(6) cells/m(3) were determined in the air of the duck hatchery and 5 × 10(7) cells/m(3) in the air of the duck house. A Generated Restriction Fragment Length Polymorphism (RFLP) pattern revealed deviant bacterial compositions comparing samples collected with both devices. Clone library analyses based on 16S rRNA gene sequence analysis from the hatchery's air showed 65% similarity between the two sampling devices. Detailed 16S rRNA gene sequence analyses showed the occurrence of bacterial species like Acinetobacter baumannii, Enterococcus faecalis, Escherichia sp., and Shigella sp.; and a group of Staphylococcus delphini, S. intermedius, and S. pseudintermedius that provided the evidence of potential exposure to risk group 2 bacteria at the hatchery workplace. Size fractionated sampling with the developed by the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) device revealed that pathogenic bacteria would deposit in the inhalable, the thorax, and possibly alveolar dust fraction according to EN481. TCC analysis showed the deposition of bacterial cells in the third stage (< 1μm) at the NIOSH device which implies that bacteria can reach deep into the lungs and contaminate the alveolus after inhalation. Nevertheless, both personal sampling devices could be recommended for exposure assessment at agricultural workplaces.

Dust, endotoxin, fungi, and bacteria exposure as determined by work task, season, and type of plant in a flower greenhouse

BACKGROUND

Greenhouse workers are exposed to dust, endotoxin, fungi, and bacteria potentially causing airway inflammation as well as systemic symptoms. Knowledge about determinants of exposure is a prerequisite for efficient prevention through knowledge-based reduction in exposure. The objective of this study was to assess the occupational exposure in a flower greenhouse and to investigate the impact of work tasks on the intensity and variability in exposure.

METHODS

Seventy-six personal full-shift exposure measurements were performed on 38 employees in a Danish flower greenhouse producing Campanula, Lavandula, Rhipsalideae, and Helleborus. The samples were gravimetrically analysed for inhalable dust. Endotoxin was assessed by the Limulus Amoebocyte Lysate test and culture-based quantification of bacteria and fungi was performed. Information on the performed tasks during sampling was extracted from the greenhouse electronic task logging system. Associations between log-transformed exposure outcomes, season, and work tasks were examined in linear mixed-effects regression with worker identity as random effect.

RESULTS

Measured concentrations ranged between 0.04 and 2.41mg m(-3) for inhalable dust and between 0.84 and 1097 EU m(-3) for endotoxin exposure, with the highest mean levels measured during Lavandula and Campanula handling, respectively. Personal exposure to fungi ranged between 1.8×10(2) and 3.4×10(6) colony-forming units (CFU) m(-3) and to bacteria between 1.6×10(1) and 4.2×10(5) CFU m(-3). Exposure to dust, endotoxin, fungi, and bacteria differed between seasons. Packing Lavandula, sticking, potting, and grading Rhipsalideae, and all examined tasks related to Campanula production except sticking increased dust exposure. Endotoxin exposure was increased during sticking Campanula and pinching or packing Rhipsalideae, and fungi exposure was elevated by subtasks performed in the research and development area for Campanula, and by potting, packing/dumping Campanula. Sticking and working with subtasks in the research and development area for Campanula increased bacteria exposure.

CONCLUSION

This study revealed moderate dust exposure levels compared to the levels observed in other greenhouse productions and other occupations with organic dust exposure such as farming. However, high exposures to bacteria and fungi were detected during selected tasks and the proposed health-based endotoxin exposure limit of 90 EU m(-3) was exceeded in 30% of the samples, which may have health implications for the employees. Exposure levels were found to vary depending on the tasks performed, and thereby results can be used to direct task-based initiatives to reduce workplace exposures.

Assessment of workers' exposure to bioaerosols in a French cheese factory

Hundreds of different cheeses are produced in France, where 23.9kg of cheese were consumed per inhabitant in 2009, when it was ranked the second cheese-consuming nation. To meet this considerable demand, a large number of cheese factories exist where many workers, especially cheese washers, may be exposed to fungal bioaerosols that can lead to adverse toxinic and allergic effects. Airborne bacteria, fragments, or microbial by-products (endotoxins) are also found and contribute to total worker exposure. However, there is almost no published data concerning worker exposure or characteristics of bioaerosols emitted during these activities. Here, we measured the parameters (concentrations, species present, and size distribution) of the culturable fungal bioaerosol emitted in a French natural-rind cheese-maturing cellar. Concentrations of airborne bacteria and endotoxins were also measured. The main tasks were investigated using stationary or personal sampling over three consecutive days. Depending on the work area, high concentrations of culturable mesophilic microorganisms were measured (using closed-face cassettes): from 10(4) to 2×10(8) CFU m(-3) for fungi and from 10(3) to 10(6) CFU m(-3) for bacteria. These concentrations are 10- to 100000-fold higher than those measured at two reference points (indoor and outdoor) that are assumed not to be contaminated by the plant's activities. Endotoxin concentrations were between 10 and 300 EU m(-3) in the plant. Exposure was further assessed by identifying the predominant culturable fungi (allergenic Mucor fuscus and Penicillium sp.) and by measuring particle size distributions (cascade impactor). Airborne fungal entities (spores, mycelium strands and fragments, agglomerates, etc.) were found with aerodynamic diameters from 3 to over 20 µm. A metrological approach was used to fully characterize the culturable fungal aerosols generated during cheese maturing in this plant. The results show that workers are exposed to concentrations of airborne culturable fungi, sometimes very high, throughout the manufacturing process. In addition to fungi, culturable bacteria and endotoxins are also present in the work atmosphere. All these microbial organisms thus contribute in a complex manner to total worker exposure. Despite the lack of both occupational exposure limit values and standardized measuring methods, our results suggest that an immunological risk may occur among workers, especially for cheese brushers, cheese washers, and packagers who are the most exposed workers in the factory.

Outdoor (1→3)-β-D-glucan levels and related climatic factors

Objectives

To evaluate the monthly variation in the airborne (1→3)-β-D-glucan level throughout one year and its relationship with climatic factors (temperature, relative humidity, wind speed, hours of daylight, cloud cover, and pollen counts).

Methods

A total of 106 samples were collected using a two-stage cyclone sampler at five outdoor sampling locations (on top of 5 university buildings). The kinetic limulus amebocyte lysate assay was used to obtain (1→3)-β-D-glucan levels.

Results

Airborne (1→3)-β-D-glucan levels were significantly higher in the spring, particularly in April, and temperature was significantly related to (1→3)-β-D-glucan levels (r =0.339, p<0.05).

Conclusions

(1→3)-β-D-glucan levels may be highest in the spring, and outdoor temperature may influence (1→3)-β-D-glucan levels.

Attempts to reduce exposure to fungi, β-glucan, bacteria, endotoxin and dust in vegetable greenhouses and a packaging unit

Indoor handling of large amounts of plant materials occurs in different occupational settings including greenhouses and causes exposure to bioaerosols. The bioaerosol components fungi, β-glucan, bacteria and endotoxin are involved in different airway symptoms and health effects can be dose-dependent. Therefore, there is a persistent need to reduce exposure. The aims of this study were to identify tasks causing exposure and to evaluate preventive measures aimed at reducing exposure of greenhouse workers to bioaerosols, and to study factors affecting the exposure. We have focused on different exposure scenarios; one with high short-term exposure found during clearing of old cucumber plants; the other with long-term, mid-level exposure found during tomato picking, leaf nipping, stringing up tomato plants, and packaging of cucumbers. Clearing of non-dried cucumber plants compared with clearing of dried cucumber plants significantly reduced the exposure to dust, endotoxin, bacteria, fungal spores and β-glucan. More endotoxin and fungi are emitted and more of the emitted particles were of respirable size if the leaves were dried. Along the cucumber packaging line, exposure levels were highly specific to each personal subtask. The subtask 'unloading of cucumbers' was the source of exposure making task ventilation or shielding of the process a possibility. Elimination of leaf debris on the floor reduced the exposure to fungi significantly. However, leaf debris on the floor did not contribute significantly to the exposure to dust, endotoxin and bacteria. Furthermore, to eliminate leaf debris, it had to be cleared away and this was associated with a higher exposure to dust and endotoxin. The age of the plants affected the exposure level to bioaerosols with higher exposures from old plants. In conclusion, different tasks and subtasks cause very different exposure levels. It is possible to reduce exposure by identifying subtasks causing the exposure and by modifying work processes, e.g., not drying out of plants.

Characterization of the monthly variation in (1 → 3)-β-D-glucan concentrations in university laboratories

We characterize the monthly variation in (1 → 3)-β-D-glucan concentration measured over the course of 1 year, and we evaluate the characteristics of size selection using a two-stage cyclone sampler. The (1 → 3)-β-D-glucan concentrations were measured in four bio-related laboratories. A total of 156 samples were collected using a new two-stage cyclone sampler. Analysis of (1 → 3)-β-D-glucan was performed using the kinetic Limulus amebocyte lysate assay. The study showed that airborne (1 → 3)-β-D-glucan concentrations were significantly higher in laboratory D (mean ± SD 1,105 ± 1,893 pg/m(3)) and in the spring (5,458 pg/m(3)). The highest concentration of (1 → 3)-β-D-glucan occurred in the spring, particularly in May.

Fungal pollution of indoor environments and its management

Indoor environments play important roles in human health. The health hazards posed by polluted indoor environments include allergy, infections and toxicity. Life style changes have resulted in a shift from open air environments to air tight, energy efficient, environments, in which people spend a substantial portion of their time. Most indoor air pollution comes from the hazardous non biological agents and biological agents. Fungi are ubiquitous in distribution and are a serious threat to public health in indoor environments. In this communication, we have reviewed the current status on biotic indoor air pollution, role of fungi as biological contaminants and their impact on human health.

Fungi, β-glucan, and bacteria in nasal lavage of greenhouse workers and their relation to occupational exposure

The nose and mouth are the first regions of the respiratory tract in contact with airborne microorganisms. Occupational exposures to airborne microorganisms are associated with inflammation and different symptoms of the airways. The purpose of this study is to investigate the relation between occupational exposure to fungi, β-glucan, and bacteria and contents of fungi, β-glucan, and bacteria in nasal lavage (NAL) of greenhouse workers. We also studied whether contents of microorganisms in NAL were related to gender, time of the work week, and runny nose. NAL samples (n = 135) were taken Monday morning and Thursday at noon and personal exposure to inhalable bioaerosols was measured during a working day. The content of fungi and β-glucan in NAL of men was affected by their exposure to fungi and β-glucan. The content of fungi, β-glucan, and bacteria in NAL was higher Thursday at noon than Monday morning. The ratios of fungi in NAL between Thursday at noon and Monday morning were 14 (median value) for men and 3.5 for women. Gender had no effect on the exposure level but had a significant effect on the content of fungi, β-glucan, and bacteria in NAL, with the highest contents in NAL of men. On Thursdays, the median content of fungi in NAL samples of men without runny noses was 9408 cfu per NAL sample, whereas the same content for women was 595 cfu per NAL sample. Workers with runny noses had fewer fungi in NAL than workers without runny noses. A higher content of β-glucan per fungal spore was found in NAL than in the air. This indicates that mainly the larger fungal spores or pollen grains deposit in the nose. The difference between genders and the fact that the content of fungi in NAL was significantly affected by the exposure indicate that the two genders are affected by the same exposure level differently.

Indoor fungal contamination: health risks and measurement methods in hospitals, homes and workplaces

Indoor fungal contamination has been associated with a wide range of adverse health effects, including infectious diseases, toxic effects and allergies. The diversity of fungi contributes to the complex role that they play in indoor environments and human diseases. Molds have a major impact on public health, and can cause different consequences in hospitals, homes and workplaces. This review presents the methods used to assess fungal contamination in these various environments, and discusses advantages and disadvantages for each method in consideration with different health risks. Air, dust and surface sampling strategies are compared, as well as the limits of various methods are used to detect and quantify fungal particles and fungal compounds. In addition to conventional microscopic and culture approaches, more recent chemical, immunoassay and polymerase chain reaction (PCR)-based methods are described. This article also identifies common needs for future multidisciplinary research and development projects in this field, with specific interests on viable fungi and fungal fragment detections. The determination of fungal load and the detection of species in environmental samples greatly depend on the strategy of sampling and analysis. Quantitative PCR was found useful to identify associations between specific fungi and common diseases. The next-generation sequencing methods may afford new perspectives in this area.

Fungal pollution of indoor environments and its management

Indoor environments play important roles in human health. The health hazards posed by polluted indoor environments include allergy, infections and toxicity. Life style changes have resulted in a shift from open air environments to air tight, energy efficient, environments, in which people spend a substantial portion of their time. Most indoor air pollution comes from the hazardous non biological agents and biological agents. Fungi are ubiquitous in distribution and are a serious threat to public health in indoor environments. In this communication, we have reviewed the current status on biotic indoor air pollution, role of fungi as biological contaminants and their impact on human health.