Occupational exposure to particulate matter in 2 Portuguese waste-sorting units

Characteristics and health effects of particulate matter emitted from a waste sorting plant

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.e., PM₁, PM_2.5 and PM₁₀) in WPCSP is an essential issue to notify policy makers about the health impacts on exposed workers. The major activities for increasing of the concentration of PM in various processing units in the WPCSP, especially in hand-picking routes I and II were related to manual dismantling, mechanical grinding, mechanical agitation, and separation and movement of waste. The results of this work showed that a negative correlation between temperature and particulate matter size followed the order PM₁₀ > PM_2.5 > PM₁. Exposure to PM_2.5 and PM₁₀ in the WPCSP lead to possible risk (HI = 5.561 and LTCRs = 3.41 × 10^-6 to 9.43 × 10^-5 for PM_2.5 and HI = 7.454 for PM₁₀). The exposure duration and the previous concentrations had the most effect on the ILCRs and HQs for PM_2.5 and PM₁₀ in all sampling sites. Hence, because WPCSP are infected indoor environments (I/O ratio > 1), the use of control methods such as isolation of units, misting systems, blower systems equipped with bag houses, protective equipment, a mechanical ventilation system, and additional natural ventilation can reduce the amount of suspended PM, enhance worker safety, and increase the recycling rate.

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.

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

Background

The 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.

Methods

Full 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.

Results

The 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.

Conclusion

The 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.

Assessment of airborne particles and bioaerosols concentrations in a waste recycling environment in Brazil

This study aims to assess the concentrations of size-fractioned particle mass (PM_1.0, PM_2.5, PM_4.0, PM₁₀) and number (PNC_0.3, PNC_0.5, PNC_1.0, PNC_2.5), bacteria, and fungi in a Materials Recycling Facility (MRF) in Brazil. The measurements were performed inside the waste processing shed (P1) and in the outdoor environment (P2) during working days in winter and spring of 2017, and summer of 2019. A total of 2,400 min of PM, 1,440 min of PNC, and 216 samples of bioaerosols were collected in the morning and afternoon. P1 has the strongest air contamination with mean values of 475.5 ± 563.7 µg m⁻³ for PM₁₀, 58.6 ± 36.0 cm⁻³ for PNC_0.3, 1,088.8 ± 825.2 colony-forming units per cubic meter (CFU m⁻³) for bacteria, and 2,738.3 ± 1,381.3 CFU m⁻³ for fungi. The indoor/outdoor ratios indicated the large influence of indoor sources due to the activities performed inside P1 that promote the generation and resuspension of pollutants. Gram-positive bacteria dominated with 58.6% of indoor samples. Overall, our results show a critical indoor air quality situation in a Brazilian MRF, which may cause several health risks for waste pickers. Finally, we call attention to the lack of occupational exposure limits for bioaerosols in industrial workplaces and mainly in MRFs.

Dust at Various Workplaces-Microbiological and Toxicological Threats

The aim of the present study was to evaluate the relation between the chemical (analysis of elements and pH) and microbiological composition (culture and metagenomics analysis) of the dust at various workplaces (cement plant, composting plant, poultry farm, and cultivated area) and the cytotoxicity effect on the human adenocarcinoma lung epithelial adherent cell line A-549 (MTT assay test). Analysis of the Particulate Matter (PM) fraction showed that the dust concentration in cultivated areas exceeded the OELs. For the remaining workplaces examined, the dust concentration was lower than OELs limits. The number of microorganisms in the dust samples was 3.8 × 10²–1.6 × 10⁸ CFU/g bacteria and 1.5 × 10²–6.5 × 10⁶ CFU/g fungi. The highest number of microorganisms was noted for dust from cultivated areas (total number of bacteria, actinomycetes, P. fluorescens) and composting plants (xerophilic fungi and staphylococci), while the least number of microorganisms was observed for dust from cement plants. Many types of potentially pathogenic microorganisms have been identified, including bacteria, such as Bacillus, Actinomyces, Corynebacterium, Prevotella, Clostridium, and Rickettsia, and fungi, such as Alternaria, Cladosporium, Penicillium, and Aspergillus. The most cytotoxic to the human lung cell line A-549 was dust from cultivated areas (IC₅₀ = 3.8 mg/mL after 72 h). The cytotoxicity of the tested dust samples depends on the PM concentration, the number of microorganisms, including potentially pathogenic genera, and the exposure time.

Exposure and risk analysis to particulate matter, metals, and polycyclic aromatic hydrocarbon at different workplaces in Argentina

In order to estimate air quality at work environments from small and medium-sized enterprises (SMEs), we determined both the concentration of particulate matter (PM₁₀ and PM_2.5) and the presence of polycyclic aromatic hydrocarbons (PAHs), as the heavy metals in the composition of the particulate matter. Three SMEs located in the city of La Plata, Argentina, were selected: an electromechanical repair and car painting center (ERCP), a sewing work room (SWR), and a chemical analysis laboratory (CAL). The results evidenced high levels of PM exceeding the limits allowed by the USEPA and the presence of benzo(k)fluoranthene in all the analyzed sites and benzo(a)pyrene in the most contaminated site (ERCP). Regarding metals, the presence of Cd, Ni, Cu, Pb, and Mn, mainly in the fraction of PM_2.5, in the same workplace was found. As far as risk assessment at all the workplaces surveyed is concerned, risk values for contracting cancer throughout life for exposed workers (LCR) did not comply with the parameters either of USEPA or of WHO (World Health Organization).

Enniatin B and ochratoxin A in the blood serum of workers from the waste management setting

The waste management occupational environment is recognized by the simultaneous presence of several substances and biologic agents. Therefore, workers are exposed simultaneously to multiple contaminants. Occupational exposure to aflatoxin B₁ in one Portuguese waste sorting plant was already reported. However, besides this mycotoxin, data regarding fungal contamination showed that exposure to other mycotoxins could be expected. A study was developed to analyze if exposure to other mycotoxins besides aflatoxin B₁ was occurring in the workers from the waste sorting plant previously assessed and to discuss how these findings need to be considered in the risk assessment process. In addition to aflatoxin B₁ detected previously by ELISA, two additional mycotoxins and one mycotoxin degradation product were detected and quantified by a multi-mycotoxin HPLC-MS/MS approach: Enniatin B and ochratoxin A as well as 2'R-ochratoxin A. Besides the confirmation of co-exposure to several mycotoxins, results probably indicate different exposure routes for the mycotoxins reported.

Microbiota and Particulate Matter Assessment in Portuguese Optical Shops Providing Contact Lens Services

The aim of this work was to assess the microbiota (fungi and bacteria) and particulate matter in optical shops, contributing to a specific protocol to ensure a proper assessment. Air samples were collected through an impaction method. Surface and equipment swab samples were also collected side-by-side. Measurements of particulate matter were performed using portable direct-reading equipment. A walkthrough survey and checklist was also applied in each shop. Regarding air sampling, eight of the 13 shops analysed were above the legal requirement and 10 from the 26 surfaces samples were overloaded. In three out of the 13 shops fungal contamination in the analysed equipment was not detected. The bacteria air load was above the threshold in one of the 13 analysed shops. However, bacterial counts were detected in all sampled equipment. Fungi and bacteria air load suggested to be influencing all of the other surface and equipment samples. These results reinforce the need to improve air quality, not only to comply with the legal requirements, but also to ensure proper hygienic conditions. Public health intervention is needed to assure the quality and safety of the rooms and equipment in optical shops that perform health interventions in patients.