Microfungal contamination of damp buildings - Examples of risk constructions and risk materials

To elucidate problems with microfungal infestation in indoor environments, a multidisciplinary collaborative pilot study, supported by a giant from th e Danish Ministry of Housing and Urban Affairs, was performed on 72 mold-in fected building materials from 23 buildings. Water leakage through roofs, r ising damp, and defective plumbing installations were the main reasons for water damage with subsequent infestation of molds. From a score system asse ssing the bioavailability of the building materials, products most vulnerab le to mold attacks were water damaged, aged organic materials containing ce llulose, such as wooden materials, jute, wallpaper, and cardboard. The micr ofungal genera most frequently encountered were Penicillium (68%), Aspergil lus (56%), Chaetomium (22%), Ulocladium, (21%), Stachybotrys (19%) and Clad osporium (15%). Penicillium chrysogenum, Aspergillus versicolor, and Stachy botrys chartarum were the most frequently occurring species. Under field co nditions, several trichothecenes were detected in each of three commonly us ed building materials, heavily contaminated with S, chartarum. Under experi mental conditions, four out of five isolates of S. chartarum produced satra toxin H and G when growing on new and old, very humid gypsum boards. A. ver sicolor produced the carcinogenic mycotoxin sterigmatocystin and 5-methoxys terigmatocystin under the same conditions. Key words: allergy, Aspergillus versicolor, building materials, mold, mycotoxins, Penicillium chrysogenum, Stachybotrys chartarum.