Risk from Inhaled Mycotoxins in Indoor Office and Residential Environments

Abstract

Mycotoxins are known to produce veterinary and human diseases when consumed with contaminated foods. Mycotoxins have also been proposed to cause adverse human health effects after inhalation exposure to mold in indoor residential, school, and office environments. Epidemiologic evidence has been inadequate to establish a causal relationship between indoor mold and nonallergic, toxigenic health effects. In this article, the authors model a maximum possible dose of mycotoxins that could be inhaled in 24 h of continuous exposure to a high concentration of mold spores containing the maximum reported concentration of aflatoxins B1 and B2, satratoxins G and H, fumitremorgens B and C, verruculogen, and trichoverrols A and B. These calculated doses are compared to effects data for the same mycotoxins. None of the maximum doses modeled were sufficiently high to cause any adverse effect. The model illustrates the inefficiency of delivery of mycotoxins via inhalation of mold spores, and suggests that the lack of association between mold exposure and mycotoxicoses in indoor environments is due to a requirement for extremely high airborne spore levels and extended periods of exposure to elicit a response. This model is further evidence that human mycotoxicoses are implausible following inhalation exposure to mycotoxins in mold-contaminated home, school, or office environments.

A year-round investigation of indoor airborne fungi in Croatia

“…Moreover, there are many unknown facts about these effects when inhalation is the primary means of exposure. However, there is a remarkable amount of studies proving toxic, mutagenic, and carcinogenic properties of mould secondary metabolites on respiratory surrogate tissues, cell lines, and animal respiratory system, as well as case-reports addressing adverse health effects in humans (4,(41)(42)(43)(44)(45)(46). Therefore, monitoring of airborne fungi in occupational as well as living environments is of great importance in the prevention of unfavourable effects on human health.…”

Biomechanics of conidial dispersal in the toxic mold Stachybotrys chartarum

“…We assume that the quantity of airborne mycotoxins increases in proportion to the area of mold growth in a particular indoor space, but it is difficult to quantify the extent of mold proliferation in situations where multiple discrete colonies are distributed over a wide area. Despite these uncertainties, the suggestion by Burge (1996) --and supported by Kelman et al (2004) --that a person living in a highly contaminated environment could accumulate no more than a few nanograms of toxin in 24 h seems very reasonable. The significance of this level of mycotoxin exposure remains uncertain.…”

Mass Spectrometry-Based Strategy for Direct Detection and Quantification of Some Mycotoxins Produced by Stachybotrys and Aspergillus spp. in Indoor Environments

“…The latter three mycotoxins have been shown to be immunomodulatory, causing a polarization in cytokine production towards a Th2 phenotype (36), and citrinin caused depletion of intracellular glutathione at nontoxic concentrations (18). Based on spore counts, the airborne mycotoxin concentrations found in damp buildings have been estimated to be insufficient for causing adverse health effects (20). However, indoor molds may fragment into very small airborne mycotoxin-containing particles, resulting in up to a 500-fold larger exposure than assumed previously (4,11,21,32).…”