Expert Services For Mold Assessment & Testing
ABF adheres to mold testing standards used by the Environmental Protection Agency (EPA). The Environmental Relative Moldiness Index (ERMI) offers a clearer picture of the various types of mold spores. ABF identifies and develops removal protocols for mold linked to respiratory problems (such as asthma) in humans. ERMI mold testing samples are prepped by EPA-licensed laboratories, of which there are only 14 worldwide. AIHA does not have an ERMI accreditation process to date but may undertake this project within the next 1-2 years. Meanwhile, the EPA has an extremely rigorous licensing process, so look for the EPA license number before utilizing an ERMI laboratory.
ERMI AND ITS ROLE IN COMPLETE MOLD REMOVAL
In 2006, a tsunami struck the fungal sampling coastlands of the USA...but hardly created a splash. The tsunami quietly seeped into the wetlands when the US EPA's Steven Vesper, Ph.D., announced the development of ERMI...the acronym for Environmental Relative Moldiness Index, on August 2006. The mold community welcomed ERMI with a yawn and a raised eyebrow. While a handful of laboratories have been promoting ERMI since last fall, its acceptance into the industrial hygiene and fungal detection disciplines has been tepid at best and relegated to the more esoteric, high-end projects such as litigation support and celebrity cases where cost is less than valued precision and accuracy. It has grown at the glacial pace of Stachybotrys in Arizona.
A Case Study
Examples of Group 1 molds include A. flavus, A. fumigatus, A. sydowii, Aureobasidium pullulans, Chaetomium globosum, Penicillium brevicompactum, P. spinulosum, Stachybotrys chartarum, Trichoderma viride, Wallemia sebi and 16 others. Group 2 molds include Acremonium strictum, Alternaria alternata, A. ustus, Cladosporium cladosporioides (I & II), P. chrysogenum and 4 others.
For each mold species within the panel, the concentration (spores/mg of dust) is converted to its algebraic log and then summed for the respective groups. The Group 2 log sum is subtracted from Group 1 to arrive at the ERMI value. This value called the Relative Moldiness Index Value, is then placed on a chart scaled from -10 to 20. Within this range, EPA has developed four categories of homes ranging from Level 1 to Level 4...the higher the level, the most likely the home has a mold problem. Level 4 homes are predicted to have the best chance of exhibiting mold contamination.
What's even more impressive is that research by Dr. Vesper and others has been able to link homes with Group 1 molds to the likely development of asthma in children living in water-damaged homes. A relative moldiness index (RMI), as seen in ERMI, was able to make this prediction. They concluded that: "The RMI values may be a useful tool for predicting the mold condition of a home. If Group 1 molds are discovered, water-damage remediation and mold removal might be considered as part of the total prevention plan in an asthmatic child's home."
EPA's Steven Vesper, Ph.D., found through exhaustive statistical analyses of bulk dust samples obtained in affected and unaffected homes that a distinction occurred by evaluating concentrations of groups of molds. HUD/EPA studied a statistically valid sample size of 1200 homes across the US, determining the levels and types of mold present. Half of the homes were known to have extensive water damage, and occupants suffered from significant respiratory illness. The other half were from unaffected homes where no respiratory distress or asthma was present. By contrasting the various mold populations in these two types of homes, he classified molds into two groups - Group 1 mold species (water impact molds) occurring in water-damaged, atypical homes; and Group 2 mold species found in all homes (common environmental molds). Group 1 molds consist of 26 species, while Group 2 molds consist of 10 species for a total of 36 total mold species.
Mold testing samples are analyzed using Mold Specific Quantitative Polymerase Chain Reaction (MSQPCR - EPA Method SOP MERB-020, rev. 3, 7/11/02). Don't bother trying to remember that...just remember DNA sequencing. MSQPCR is a highly accurate and sensitive molecular technique for the detection of molds. It is objective and specific because it is a detection system based on unique DNA sequences. Just as humans have unique DNA sequences that provide statistical probabilities of 1,000,000,000:1 odds, so do environmental fungi. The DNA sequence for Aspergillus fumigatus is uniquely different from A. flavus and A. Versicolor. As popularized by the criminal forensics program CSI, "DNA doesn't lie." It's as close to the statistical truth as possible, with an accuracy of 99.99%.
ABF advances the practice of infrared thermography imaging. The presence of water not visible to the naked eye and moisture content in building materials is now measurable with our advanced tools. ABF can highlight water penetration and calculate your damage risk with detailed images.
WATER DAMAGE IN BUILDING MATERIALS
Water activity (Aw) is defined as the partial pressure of water relative to the vapor pressure of pure water at the same temperature or a measurement of the water that is available for biological and chemical reactions. The Aw scale starts from 0 (dry) and goes to 1.0 (pure water). Microbial growth can start as low as 0.6 Aw. However, environmental molds have genera/species-specific variability regarding how much water is required for their growth.
Fungi that require high amounts of available water are called hydrophilic and grow at water activities above 0.90. Stachybotrys sp., Chaetomium sp., Trichoderma sp., Memnoniella sp., Acremonium sp., and Fusarium sp. are examples of hydrophilic molds. They colonize only in moisture-rich, chronically moist environments. If building materials do not contain >90% (Aw >0.9) moisture content, then their growth is impaired. The largest group of fungi falls in the mesophilic range.
Mesophilic fungi include common indoor molds such as Cladosporium sp. and Alternaria sp. These fungi typically grow on continuously damp building materials with water activities between 0.80 and 0.90. Xerotolerant molds include Aspergillus sydowii, A. versicolor, and some species of Penicillium are able to grow at water activities below 0.80 but grow optimally above this value. They are common on water-damaged materials.
The final group of fungi, known as xerophilic, actually grow best at water activity ratios below 0.80.
A common xerophilic fungus is Aspergillus restrictus. Building materials such as drywall and wood contain cellulose-based materials chocked full of nutrients that serve as suitable food sources for mold growth. However, unless the water is present at the levels presented above, mold growth will not occur. Water impact into a structure then provides the enriched moisture environment fungi need to grow. Once a building product is soaked with water without immediate drying, mold spores present on the water-laden building material germinate and grow.
With some molds, the building product must remain nearly saturated for 8-12 days (e.g., Stachybotrys chartarum) before growth appears. Once they grow and water activity falls below their requisite Aw level, the fungi either become dormant or die - but they don't disappear. They remain on the building material as a forensic clue or signature documenting the historic water impact of the building. This is why the aforementioned molds are referred to as "Water Impact" or "Signature Molds."
Their presence, either in the air or on a surface, is like a fingerprint...a distinct and measurable surrogate indicator that the building material in question sustained an anomalous and significant water impact. Their absence indicates either that there was no water impact or that water was not retained for an adequate period of time for these organisms to germinate and colonize. Building materials may have water damage without the presence of water impact molds.
Opportunistic Fungal Pathogens
ABF is now offering a new sampling method to detect Opportunistic Fungal Pathogens (OFP) for healthcare facilities, long-term care, immuno-compromised patients, and pharmaceutical production facilities. The new Sporometrics agar-based method: