Molds and Mycotoxins in Indoor Environments — A Survey in Water-Damaged Buildings

Abstract

Mycotoxins are toxic, secondary metabolites frequently produced by molds in water-damaged indoor environments. We studied the prevalence of selected, potent mycotoxins and levels of fungal biomass in samples collected from water-damaged indoor environments in Sweden during a 1-year period. One hundred samples of building materials, 18 samples of settled dust, and 37 samples of cultured dust were analyzed for: (a) mycoflora by microscopy and culture; (b) fungal chemical marker ergosterol and hydrolysis products of macrocyclic trichothecenes and trichodermin (verrucarol and trichodermol) by gas chromatography-tandem mass spectrometry; and (c) sterigmatocystin, gliotoxin, aflatoxin B₁, and satratoxin G and H by high performance liquid chromatography-tandem mass spectrometry. Sixty-six percent of the analyzed building materials samples, 11% of the settled dust samples, and 51% of the cultured dust samples were positive for at least one of the studied mycotoxins. In addition, except in the case of gliotoxin, mycotoxin-positive building material samples contained 2–6 times more ergosterol than mycotoxin-negative samples. We show that (a) molds growing on a range of different materials indoors in water-damaged buildings generally produce mycotoxins, and (b) mycotoxin-containing particles in mold-contaminated environments may settle on surfaces above floor level. The mass spectrometry methods used in this study are valuable tools in further research to survey mycotoxin exposure and investigate potential links with health effects.

Keywords:

• ergosterol
• indoor environments
• mass spectrometry
• molds
• mycotoxins
• water damage

ACKNOWLEDGMENTS

We thank Poul Rasmussen (Leo-Pharma, Denmark) for trichodermin and Professor Bruce B. Jarvis (University of Maryland) for mycotoxin standards. SBUF, FORMAS, the Swedish Asthma & Allergy Association, and Queen Silvia's Jubilee Fund for Research on Children and Children's Disabilities are gratefully acknowledged for financial support.

Notes

^A Other taxa found in one sample only included Scopulariopsis (wallpaper), Philaphora (other, namely, plastic floor material), and Olpitrichum, Fusarium, Geomyces, Auerobasidium, and Mumicola (RCS cultures).

^B Five flooring materials, four painted wall materials, and one inventory.

^C Amounts of ergosterol (mean; median) in the studied building materials (ng/mg), settled dust samples (ng/mg), and in RCS cultures (mg/cm²).

^A Five flooring materials, four painted wall materials, and one inventory.

^B Amounts (mean values) of ergosterol in the mycotoxin-positive vs. mycotoxin-negative samples studied.