Exposición laboral a hongos y bacterias ambientales en una planta de selección de residuos de envases

Occupational exposure to inhalable pathogenic microorganisms in waste sorting

This study assessed microorganisms in personal inhalable work air samples aiming to identify potential human pathogens, and correlate exposure to adverse health outcomes in waste workers. Full-shift personal exposure was measured in six different waste sorting plants. Microbial concentrations in inhalable air samples were analysed using MALDI-TOF MS for cultivable, and next generation sequencing (NGS) for non-cultivable microorganisms. Concentrations of bacterial and fungal CFUs varied substantially within and between waste sorting plants, ranging from no identifiable organisms to a maximum concentration in the order of 105 CFU/m3. Bacillus and Staphylococcus were among the most abundant bacterial genera, whilst fungal genera were dominated by Aspergillus and Penicillium. Approximately 15% of all identified species were human pathogens classified in risk group 2, whereas 7% belonged to risk group 1. Furthermore, significant correlations between concentrations of fungi in risk group 1 and self-reported adverse symptoms, such as wheezing were identified in exposed workers. The combination of culture-based methods and NGS facilitated the investigation of infectious microbial species with potential pathophysiological properties as well as non-infectious biological agents in inhalable work air samples and thereby contributed to the risk assessment of occupational exposure in waste sorting.

Characteristics and assessing biological risks of airborne bacteria in waste sorting plant

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m^-3) were: Staphylococcus sp. (72.4) > Micrococcus sp. (52.2) > Bacillus sp. (30.3) > Enterococcus sp. (24.0) > Serratia marcescens (20.1) > E. coli (19.1) > Pseudomonas sp. (16.0) > Nocardia sp. (1.9). The lifetime average daily dose (LADD) for the inhalation and dermal routes for the intake of airborne bacteria ranged from 3.7 × 10^-3 ≤ LADD_Inhalation ≤ 2.07 × 10¹ CFU (kg d)^-1 and 4.75 × 10^-6 ≤ LADD_Dermal ≤ 1.64 × 10^-5 CFU (kg d)^-1, respectively. Based on a sensitivity analysis (SA), the concentration of airborne bacteria (C) and the exposure duration (ED) had the most effect on the LADD_Inhalation and LADD_Dermal for all sampling locations. Although the Hazard Quotient of airborne bacteria was HQ < 1, an acceptable level, the indoor/outdoor ratio (1.5 ≤ I/O ≤ 6.6) of airborne bacteria typically exceeded the threshold value (I/O > 2), indicating worker's exposure to an infected environment. Therefore, in the absence of sufficient natural ventilation the indoor ambient conditions of the WPCSP studied should be controlled by supplying mechanical ventilation.

Land Use Effects on Airborne Bacterial Communities Are Evident in Both Near-Surface and Higher-Altitude Air

Land use influences the composition of near-surface airborne bacterial communities, and bacteria can be transported through the atmosphere at global scales. The atmosphere mixes vertically, but rigorously assessing whether the effects of land use on atmospheric communities extends to higher altitudes requires examining communities from multiple altitudes collected at a stable location and timeframe. In this study, we collected near-surface (<2 m) and higher-altitude (150 m) air samples from three sites in an agricultural/developed location and a forested/undeveloped location. We used bacterial 16S rRNA amplicon sequencing to compare communities and predict functionality by altitude. Higher-altitude and near-surface communities did not differ in composition within each location. Communities collected above the undeveloped location were equally variable at both altitudes; higher-altitude samples from the developed location predominantly contained Firmicutes and were less variable than near-surface samples. We also compared airborne taxa to those present in soil and snow. Communities from higher-altitude samples above the developed location contained fewer overlapping taxa with soil and snow sources, and overlapping Operational Taxonomic Units (OTUs) among the three sources differed by location. Our results suggest that land use affects the composition of both near-surface and higher-altitude airborne bacterial communities and, therefore, may influence broad bacterial dispersal patterns. This small-scale pilot study provides a framework for simultaneously examining local and regional airborne microbial communities that can be applied to larger studies or studies using different types of samplers.

Air Quality and Potential Health Risk Impacts of Exposure to Bacterial Aerosol in a Waste Sorting Plant Located in the Mountain Region of Southern Poland, Around Which There Are Numerous Rural Areas

Many studies have shown an association between working in waste sorting plants (SP) and occupational health problems, such as skin irritation or pulmonary diseases. These symptoms have been related to biological aerosol exposure. The main goal of this work was to assess the levels of concentration and the characteristics of bacterial aerosols in waste sorting plants, based on measurements taken in a plant located in the mountain region of Southern Poland, around which there are numerous rural areas. The average concentrations of culturable bacterial aerosol (CCBA) collected in the unloading hall of the waste sorting plant (UHSP) and the outdoor air of the sorting plant (OSP) were 2687 CFU/m3 and 1138 CFU/m3, respectively. Sampling was undertaken in the plant using an Andersen six-stage impactor (with aerodynamic cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 μm), during the spring of 2019. Size distributions were unimodal, with a peak in particle bacterial aerodynamic diameters at less than 3.3 µm, increasing the potentially adverse health effects of their inhalation. An analysis was conducted to determine the antibiotic resistance of isolated strains of bacteria. During the study, it was found that isolates belonging to the genus Bacillus were most frequently detected in the waste sorting plant. Isolates with the highest resistance to antibiotics belonged to the genus Neisseria. This test indicates that the use of personal protective equipment is necessary.

Extension of the sorting instructions for household plastic packaging and changes in exposure to bioaerosols at materials recovery facilities

The aim of this study was to assess how extending the sorting instructions for plastic packaging would affect the exposure of workers working at materials recovery facility (MRF) to dust, endotoxins, fungi and bacteria, taking into consideration other factors that could have an influence on this exposure. Personal sampling was carried out at four MRFs during six sampling campaigns at each facility, both in sorting rooms and when the workers were involved in "mobile tasks" away from the rooms. The data was analysed by describing the extension of sorting instructions both using a qualitative variable (after vs before) and using data for the pots and trays recycling stream, including or excluding plastic film. Overall, before the extension of the sorting guidelines, the geometric mean of personal exposure levels in sorting rooms was 0.3mg/m(3) for dust, 27.7 EU/m(3) for endotoxins, 13,000 CFU/m(3) for fungi and 1800 CFU/m(3) for bacteria. When workers were involved in mobile tasks away from the rooms, these averages were 0.5mg/m(3), 25.7 EU/m(3), 28,000 CFU/m(3) and 5100 CFU/m(3) respectively.The application by households of instructions to include pots, trays and film with other recyclable plastic packaging led to an increase in exposure to endotoxins, fungi and bacteria at MRFs. For an increase of 0.5 kg per inhabitant per year in the pots, trays and film recycling stream, exposure in sorting rooms rose by a factor of 1.4-2.2, depending on the biological agent. Exposure during mobile tasks increased by a factor of 3.0-3.6. The age of the waste amplified the effect of the extension of sorting instructions on exposure to fungi, bacteria and endotoxins. Factors that had a significant influence on the exposure of workers to dust and/or bioaerosols included the presence of paper, newspapers and magazines in the sorted waste, the order in which incoming waste was treated and the quality of the ventilation system in the sorting rooms. The levels of exposure observed in this study highlight the need to implement appropriate preventive measures against bioaerosols at MRFs for dry waste. There are grounds to justify these preventive measures, both inside sorting rooms and for the MRF as a whole, regardless of whether the decision to extend sorting instructions for household plastic waste is adopted.

Airborne microorganisms associated with packaging glass sorting facilities

In recent years, efforts have been undertaken to reduce the volume of residual waste through sorting and recycling. The waste management and recycling sector is thriving and the number of workers there is increasing. In this context, prior knowledge of the risks to which workers may be exposed is of crucial importance, and preventive measures need to be put in place to accurately identify and quantify those risks. This study aimed to assess occupational risk of exposure to biological agents (viable bacteria and fungi) in a Portuguese waste packaging glass sorting plant. Air samples were collected from selected locations in waste sorting cabins (critical area, CA), administrative services (noncritical area, NCA) and outdoors (control point, CP). Duplicate air samples were collected through an impaction method. The investigation was carried out over an 8-mo period with two collection periods, autumn/winter (AW) and spring/summer (SS), in order to access the influence of any seasonal variation. In the 36 air samples collected, 319 bacterial and 196 mold identifications were performed. Air samples revealed existence of high environmental contamination by bacteria (1.6 × 10(4) colony forming units [cfu]/m(3)) and fungi (1.5 × 10(4) cfu/m(3)). The predominant bacterial genus was Staphylococcus (coagulase negative) with values ranging from 29.6 to 60% of the total count of bacteria. Genera Bacillus, Micrococcus, and Staphylococcus (coagulase negative) were also present at all sampling sites, regardless of the season. However, the counts of these genera, in the CA, were higher in warmer seasons. The genus Penicillium was the most frequent genus present with an approximate value of 95% of total fungal count in the CA. Seasonal variation was a significant factor for total bacteria and fungi, except for NCA versus CP. Overall, the highest levels of bacterial and fungal species (10(4) cfu/m(3)) were found in the waste sorting cabin (CA). These results highlight the importance of proper design and risk evaluation when planning a new waste facility, such that working conditions minimize proliferation of biological agents in the workplace.