Molds and mycotoxins indoors I: Current issues and way forward

Molds are known to cause a variety of allergies in people living or working in mold-infested buildings. Molds produce mycotoxins that can be immunotoxic, neurotoxic, pulmotoxic, nephrotoxic, hepatotoxic, developmental toxic, and carcinogenic in nature. These adverse health effects are more pronounced in immunocompromised and/or genetically predisposed individuals. Even with this understanding, numerical standards for acceptable quantities of molds in indoor environments is not supported by the regulatory agencies like U.S. EPA, FDA, and professional organizations like Institute of Inspection, Cleaning and Remediation (IICRC), American Industrial Hygiene Association (AIHA), and the American Conference of Governmental Industrial Hygienists (ACGIH). Researchers are working to establish acceptable limit of molds in indoor environments based on the genus or species and adverse health effects of their biotoxins, especially mycotoxins; however, lack of standardization of sampling and analysis results in variability across laboratories making exposure assessment and interpretation of the results challenging. Establishment of exposure limits (e.g., reference dose/concentration [RfD/RfC], tolerable daily intake [TDI], slope factor) along with standard and validated methods for sampling, analysis, and reporting of molds and mycotoxins is necessary given the fact that climate change is raising both temperature and humidity resulting in increased mold growth, sporulation, and fungal diseases. This series of three papers outline the issues of molds and biotoxins, current practices, and propose improvements to standardize and validate methods of sampling, analysis, and reporting across testing laboratories.