DNA Forensic Mold Detection
04/24/07
Extensive research conducted by the US EPA, using State-of-the-Art DNA forensics, has
established the Environmental Relative Moldiness Index, otherwise known by the
acronym ERMI. The ERMI study narrowed down the total number of critical mold
species to 36 indoor-indicator mold species. Furthermore, the 36 species were
subdivided into two very different groups of mold (fungal) species; these included the
Group 1 and Group 2 molds. The Group 2 molds were found to be common in most
homes and in low concentrations. Occupants living and working in indoor environments
that contained predominantly Group 2 molds were healthy and suffered few respiratory
related illnesses, nor did the building structures suffer leaks and water intrusion.
However, Group 1 molds were much less benign, and occupants of these homes and
environments suffered significant respiratory and asthma related illnesses. Moreover,
Group 1 molds were significantly correlated to water intrusion due to poor construction
or leaking pipes. Furthermore, EPA scientist and other reputable scientific investigators
have amassed a body of published scientific research that conveys a major paradigm shift
in the way mold samples are both collected and analyzed.
Currently 99% of all mold samples are collected from the air. Inspectors pump air, often
for as little as 5 minutes, onto a sticky device called a spore-trap (not unlike flypaper).
They send the spore trap to a lab for analysis, and the lab spits back a report, based on the
shape and size of the spores they see. It is important to keep in mind, that a mold cannot
be identified as belonging to a particular species using a spore trap analysis, regardless of
how much training or how many degrees a spore trap analyst has. Unfortunately, many
of the group 1 and group 2 mold spores are small and round and all get lumped into a
common small-round spore trap grouping called Asp/Pen. Hence, neither an ERMI score
nor any substantial conclusion can be drawn from spore trap analysis.
The EPA solved this problem by using good science to make major breakthroughs in both
mold sampling and analysis.
First, the EPA identified the best technology, to date, to
identify mold. That technology is called quantitative PCR or qPCR for short. Quantitative PCR is used in many fields of science, such as genetics and cancer research.
The qPCR technology directly probes the DNA of mold with 99.9% accuracy to detect
which species of mold are present and how many spores of each species are
contaminating the indoor environment.
Secondly, the EPA used qPCR to probe the DNA
of molds from the various reservoirs in homes. Surprisingly, they found air to be a poor
correlate for detecting group 1 mold contamination (the water intrusion/asthma molds).
So they looked elsewhere, and found that every indoor environment harbors a stable mold
reservoir; that reservoir was dust.
Moreover, the dust held an historical account of indoor
mold. Hence, indoor dust has a historical moldy tale to tell, which is read from mold
DNA. Sometimes that tale is the sorrowful account of leaky roofs, windows or pipes (the
DNA identifies many group 1 mold species), other times it is a story of a happy dry home
(common group 2 mold species).
All buildings have dust and by analyzing the DNA in
that dust for mold, all skeletons come out of the closet. And those skeletons, whether
good or bad, are reflected in the EPA's ERMI index. The ERMI index is just a score
based on the amounts of group 1 (water intrusion) versus group 2 molds (common). The
ERMI score from DNA analysis of dust lets a building or home owner know whether
their home has group 2 molds and is similar to the rest of the healthy homes identified in
the EPA studies, or if it is infested by group 1 mold species, where water intrusion and
respiratory problems are common.
By: Edward A. Sobek, Ph.D.
Published Scientific Literature
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About The Chiodo Companies, Inc
The Chiodo Companies, Inc. is a diversified family of corporations, with interests in Biotechnology, Indoor
Air Quality and Infrared Thermography. Its Clean Air Labs subsidiary focuses on research and
development of customized biotechnology solutions for the indoor air quality market. Through Clean Air
Inspections and Infrared Consultants subsidiaries, The Chiodo Companies, Inc. provides clients with indoor
air environmental, building science and non-destructive consulting services.
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