Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID-a new feasible approach for the detection of an exposure to indoor mould fungi?

Abstract

A new, analytically valid procedure is described to assess the exposure of human beings to the so-called microbial volatile organic compounds (MVOCs) in air. The method can be used routinely for large sample numbers and is especially valuable as a basis for further research on the correlation between single MVOCs and indoor mould growth. The procedure is based on the fact that fungi produce a variety of volatile organic compounds, such as 3-methylbutan-1-ol, 3-methylbutan-2-ol, fenchone, heptan-2-one, hexan-2-one, octan-3-one, octan-3-ol, pentan-2-ol, alpha-terpineol, and thujopsene, which they emit into the indoor environment. Using diffusive samplers, these MVOCs are adsorbed onto charcoal during a sampling interval of four weeks. The described method is thus superior to existing methods which use short-term active sampling. After desorption with carbon disulfide, the MVOCs were determined by dual-column gas chromatography with flame ionization detection using the large-volume injection technique for sample introduction. The detection limits ranged between 0.15 and 0.53 microgram m-3, within-series precision was found to range between 6.5 and 19.0%, and recovery was between 77 and 118%. The procedure has been successfully applied in the context of a large field study to measure the indoor MVOC exposure in children's rooms of 132 dwellings. The objective of the study was to examine the relation between indoor mould growth, the indoor MVOC exposure and the prevalence of adverse health effects. Information about mould formation has been obtained by a questionnaire and by the determination of colony forming units of mould fungi in mattress dust. With the exception of 3-methylbutan-2-ol, fenchone, nonan-2-one, octan-2-one, and thujopsene, indoor air concentrations of all MVOCs under investigation were significantly higher inside damp and mouldy dwellings. From the primary MVOCs under investigation, 3-methylbutan-1-ol, hexan-2-one, heptan-2-one, and octan-3-ol were found to be most reliable indicators for mould formation. A correlation was also found between selected MVOCs and the occurrence of mould species in mattress dust. Aspergillus sp. correlated with heptan-2-one, hexan-2-one, octan-3-ol, octan-3-one, and alpha-terpineol, while the occurrence of Eurotium sp. was correlated with higher indoor air concentrations of 3-methylbutan-1-ol, 3-methylbutan-2-ol, heptan-2-one, hexan-2-one, octan-3-ol, and thujopsene. Children living in dwellings with elevated MVOC levels had a higher prevalence of asthma, hay fever, wheezing, and irritations of the eyes. These positive associations persisted after controlling for confounding factors such as age, sex, body-mass index, number of siblings, social status, passive smoking, type of heating, and ventilation habits. However, they were not statistically significant. This lack of significance may be a result of the small number of investigated samples.

The relationship between exposure to microbial volatile organic compound and allergy prevalence in single-family homes

“…The recommended maximum level of 1-octen-3-ol for indoor air, based on data from animal studies, is estimated to be 100 µg/m 3 (Korpi et al, 1999). Actual average indoor MVOC concentrations in dwellings have been found to be up to 2 µg/m 3 (Araki et al, 2009;Elke et al, 1999;Matysik et al, 2009), which is far lower than those found in experimental studies and than the recommended maximum level. In response to these findings, one study suggested that the apparent relationship between health outcomes and MVOCs could be due to exposure to the microorganisms themselves (Smedje et al, 1996).…”

“…Two studies on MVOC exposure and asthma and allergies in schools found a relationship between MVOC exposure and an increased odds ratio (OR) for the occurrence of wheezing, nocturnal breathlessness, doctor-diagnosed asthma, and history of asthma among pupils and among employees (Kim et al, 2007;Smedje et al, 1996). There has been only one study of the home setting, which found that children living in dwellings with higher MVOC concentrations had a higher prevalence of asthma, hay fever, and wheezing, and the results were not statistically significant (Elke et al, 1999).…”

Detection of volatile metabolites of moulds isolated from a contaminated library

“…Similar to our results, Wady et al (2003) detected 2-pentanol, 3-octanone, 1-octen-3-ol and 2-methyl-1-butanol for cultures of A. penicillioides isolated from mineral wood onto DG18 medium. For E. chevalieri, the only similar compound compared to Elke et al (1999) was 3-methylbutan-1-ol regarding the analysis of Eurotium species isolated from indoor dust samples on DG18 medium.…”

“…Since the 1990s, MVOCs are often discussed to be associated with the sick building syndrome (SBS) because of their suspected role as responsible for a wide range of specific and non-specific symptoms and discomfort (Elke et al, 1999;Larsen et al, 1998;Matysik et al, 2008;Meyer et al, 1998;Wessén and Schoeps, 1996).…”

05/01826 Microbial volatile organic compounds as indicators of fungi. Can an electronic nose detect fungi in indoor environments?

“…From several so-called MVOCs analysed by Elke et al [30] in damp and mouldy houses, 3-methylbutan-1-ol, hexan-2-one, heptan-2-one and octan-3-ol were found to be the most reliable indicators for mould formation. A correlation was found between Aspergillus sp, and heptan-2-one, hexan-2-one, octan-3-ol, octan-3-one and alpha-terpineol, while the occurrence of Eurotium sp.…”