RESUMO
Many fungi can develop on building material in indoor environments if the moisture level is high enough. Among species that are frequently observed, some are known to be potent mycotoxin producers. This presence of toxinogenic fungi in indoor environments raises the question of the possible exposure of occupants to these toxic compounds by inhalation after aerosolization. This study investigated mycotoxin production by Penicillium brevicompactum, Aspergillus versicolor, and Stachybotrys chartarum during their growth on wallpaper and the possible subsequent aerosolization of produced mycotoxins from contaminated substrates. We demonstrated that mycophenolic acid, sterigmatocystin, and macrocyclic trichothecenes (sum of 4 major compounds) could be produced at levels of 1.8, 112.1, and 27.8 mg/m2, respectively, on wallpaper. Moreover, part of the produced toxins could be aerosolized from the substrate. The propensity for aerosolization differed according to the fungal species. Thus, particles were aerosolized from wallpaper contaminated with P. brevicompactum when an air velocity of just 0.3 m/s was applied, whereas S. chartarum required an air velocity of 5.9 m/s. A. versicolor was intermediate, since aerosolization occurred under an air velocity of 2 m/s. Quantification of the toxic content revealed that toxic load was mostly associated with particles of size ≥3 µm, which may correspond to spores. However, some macrocyclic trichothecenes (especially satratoxin H and verrucarin J) can also be found on smaller particles that can deeply penetrate the respiratory tract upon inhalation. These elements are important for risk assessment related to moldy environments.IMPORTANCE The possible colonization of building material by toxinogenic fungi in cases of moistening raises the question of the subsequent exposure of occupants to aerosolized mycotoxins. In this study, we demonstrated that three different toxinogenic species produce mycotoxins during their development on wallpaper. These toxins can subsequently be aerosolized, at least partly, from moldy material. This transfer to air requires air velocities that can be encountered under real-life conditions in buildings. Most of the aerosolized toxic load is found in particles whose size corresponds to spores or mycelium fragments. However, some toxins were also found on particles smaller than spores that are easily respirable and can deeply penetrate the human respiratory tract. All of these data are important for risk assessment related to fungal contamination of indoor environments.
RESUMO
Asbestos fibres, when released into the air, can pose serious health hazards to exposed people. The aim of this study was to determine the concentration of respirable asbestos fibres in a highly urbanized and densely populated town, where asbestos-containing materials have been widely used in building constructions. Their presence and degree of corrosion were the main criterion for location of sampling stations. All air samples were collected applying the recently elaborated sampling strategy. The origin of sampled fibres was additionally proved by SEM analysis. Concentrations of respirable fibres, derived from 2 groups of asbestos minerals (crocidolite and chrysotile) varied from 0.0010-0.0090 f/cm(3). The highest concentrations were observed in the immediate vicinity of the buildings where a large accumulation of damaged asbestos-containing materials was found, compared to sites located from 100-500 m from such buildings, or treated as a "free" from asbestos sources. It was revealed that even a relatively gentle air movement (1 m/s) plays an important role in the spreading of fibres near the asbestos source. The data of spatial distribution of respirable asbestos fibres in the form of a map can be a useful tool for the official bodies to plan necessary asbestos remediation actions.