Aerosolization of Mycotoxins after Growth of Toxinogenic Fungi on Wallpaper

Abstract

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/m 2 , 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 Ն3 m, 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. IMPORTANCEThe 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.

Metabolic Activity of Micromycetes Affecting Urban Concrete Constructions

“…The most part 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 into human respiratory tract [30] contributing to sick building syndrome which is considered to be a multifactorial health problem of the overwhelming majority of the population in cities [31]. The relevance of the concrete biodeterioration study itself and its consequences for the environment and human health is constantly increasing.…”

Asthma Case Cluster during Renovation of a Water-Damaged and Toxic Building

“…When toxigenic fungi grow on wallpaper, aerosolisation of non-volatile mycotoxins may occur even during normal ventilation conditions [27]. In outdoor air, fungal spores can be detected throughout the year at very high counts, while more than 50,000 fungal spores/m 3 of air per day can be observed from June to August in Leicester, UK [28].…”

“…The median age of the 21 asthma patients, who comprised 7.2% of the 290 workers, was 43 years (range, 30-60 years). Their median body mass index was 27 (range, [22][23][24][25][26][27][28][29][30][31][32][33], with five (23.8%) having a value > 30. Two patients were ex-smokers, one had a history of atopy and allergic rhinitis, and two more had allergic rhinitis (Table 1).…”

Mould in building disputes

“…This can easily occur when a building becomes water damaged or building elements containing a suitable carbon source like cellulose or lignin containing timbers or plasterboard or even the glue used for wallpaper become wet and in turn become colonized by any of the fungi that are found in the normal airspace within the home or are introduced through human movement creating aerosolized bioplumes into the airspace. 35…”