Survival of Microorganisms on Filtering Respiratory Protective Devices Used at Agricultural Facilities

Wood dust effects on carpenters pulmonary function test parameters: a comparative study

BACKGROUND

Few studies have investigated the effects of wood dust on carpenters, who are frequently exposed to this hazardous material. This study aimed to determine the effects of wood dust exposure on carpenters pulmonary function test (PFT) parameters.

METHODS

This comparative cross-sectional community-based study included 130 participants; a group of carpenters and a matched cohort. Standard techniques were used to measure each participant's force vital capacity (FVC), force expiratory volume in one second (FEV1), FEV1/FVC ratio, and peak expiratory flow rate (PEFR). Statistical tests were employed to investigate different variables. A P value of < 0.05 is considered significant.

RESULTS

Carpenters had a mean age of 51.6 ± 19.9 years, whereas the matched cohort had a mean age of 49.8 ± 13.9 years. Approximately 23 (35.4%) carpenters experienced respiratory problems. Carpenters had significantly lower FEV1, FVC, FEV1/FVC%, and PEFR values than the matched cohort (P < 0.001). Additionally, the association between the carpenters duration of exposure to wood dust and their PFT values showed a significant statistical difference (P < 0.05). Likewise, the correlation between the duration of exposure to wood dust and their PFT values was significant (< 0.001).

CONCLUSIONS

Wood Dust's Effects on carpenters' respiratory systems are worth further discussion. Awareness campaigns should be undertaken to educate carpenters about lung health and preventative measures.

Cytotoxicity of filtering respiratory protective devices from the waste sorting industry: A comparative study between interior layer and exhalation valve

Filtering respiratory protection devices (FRPD) are mandatory for workers to wear in the Portuguese waste-sorting industry. Previous results regarding microbial contamination found on FRPD interior layer raised the question of whether microbial contamination from the exhalation valve would also have cytotoxicity effects. Since the FRPD exhalation valves are very close to workers' nose and mouth, they represent a source of exposure to bioburden by inhalation. This study aimed to evaluate the cytotoxicity of the microbial contamination present in the FRPD exhalation valves. For this purpose, the cytotoxicity effects were determined through the MTT assay in two different cell lines (human A549 epithelial lung cells, and swine kidney cells) and compared with previous results obtained with FRPD interior layers. The contamination present in the FRPD exhalation valves presented some cytotoxicity on epithelial lung cells, suggesting the inhalation route as a potential route of exposure through the use of FRPD in the waste-sorting industry. Half-maximal (50%) inhibitory concentration (IC50) values were lower for FRPD interior layer than exhalation valves in lung cells, with overall cytotoxicity lower in exhalation valves when compared to interior layer (z = -4.455, p = 0.000). Higher bacterial counts in TSA were correlated with lower IC50 values, thus, higher cytotoxicity effect in lung cells. No statistically significant differences were detected among different workplaces.

Cytotoxic effect of filtering respiratory protective devices from the waste sorting industry: is in vitro toxicology useful for risk characterization?

The use of Filtering Respiratory Protective Devices (FRPD) is mandatory in Portugal to protect workers from the waste industry of harmful exposures. Deleterious health effects of exposure to bioburden via inhalation and/or ingestion include respiratory symptoms and nephrotoxicity. Between January and February 2019, 118 FRPD samples were collected in one waste sorting industry and characterized regarding microbial contamination and cytotoxicity, defined as cell metabolic activity, through the MTT colorimetric assay (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide). Cytotoxic effect was classified according to percentage of extinction values with respect to the control group, as follows: absent (≥90); low (80%-90%, +); medium (60%-79%, ++); and high (below 60%, +++). For 113 samples the MTT assay revealed a cytotoxic effect in A549 cells, of which 81 presented high cytotoxicity. In SK cells, a cytotoxic effect was observed in 56 samples, of which five displayed a high cytotoxic effect. Several moderate (p < 0.05) to strong (p < 0.01) correlations were found between higher bacterial and fungal counts both in interior layers (fungi and bacteria) and in exhalation valves (fungi) of FRPD samples and reduced cell metabolic activity of SK cells. On the basis of the obtained results for the cytotoxic effect of FRPD samples on two different cells lines, it was determined that A549 cells exhibited a cytotoxic effect for a higher number of FRPD, whereas the SK cells model correlated better with the other assessed parameters, namely, bacterial and fungal counts and conditions of FRPD use. Although the results are not conclusive on the most appropriate cell line to assess FRPD cytotoxicity, they reinforce the importance of in vitro toxicology in exposure assessments to determine the cytotoxicity of mixtures of contaminants, for better risk characterization and selection of appropriate risk management measures.