Assessment
and investigation of indoor air quality issues, water damage
claims, occupant health complaints, and remediation efforts
associated with water incursions begin with water source
identification. IICRC (The Institute of Inspection, Cleaning
and Restoration Certification) has classified water damage
into three (3) different categories that take into
consideration the source, contents, history and
characteristics of the water. Proper identification and
confirmation of the water damage is imperative to the health
and safety of the occupants as well as to the remediation team
that restores the structure.
Category 1, Clean Water, is water that does
not pose health risks and source origination is from water
that does not contain contaminants. Examples of clean water
sources are broken water lines, malfunctioning appliances,
toilet tanks, snow, rainwater, or melting ice. Upon contact
with structures, surfaces, and building materials clean water
can progress to category 2 water.
Category 2, Gray Water, can pose health
risks and can contain significant levels of chemical and
biological contamination. Water discharged from dishwashers,
washing machines, sinks, showers, aquariums, and waterbeds are
excellent examples of gray water. Extensive gray water
contamination (flooding) or gray water exposed to
environmental stresses (time and temperature changes) can
progress to category 3 water in as little as 48 hours.
Category 3, Black Water, contains sewage
and other contaminants that can include pesticides, heavy
metals and toxic organic and inorganic chemicals. More than
120 different viruses, parasitic agents such as Giardia,
Cryptosporidium, and Entamoeba histolytica, and
bacterial organisms such as Klebsiella, Salmonella,
Escherichia coli, and Enterobacter, can be found
in category 3 water. Black water originates from domestic and
industrial wastes, and non-point (groundwater, surface water,
sea, river, and atmospheric) sources.
Health effects from exposure to gray and
black water range from allergic reactions to infectious
diseases, including gastroenteritis, respiratory infection,
eye infections, and inflammation of the liver.
Testing for Escherichia coli (E.
coli), Enteroccocus and total coliforms has been
the industry standard for the indication of possible sewage,
and/or black and gray water contamination in environmental
samples. Positive results for any one of the three indicators
imply the “potential” presence of disease causing
organisms, sewage contamination, or water pollution.
Alternatively, negative results indicate that the
microbiological quality of the sample is acceptable.
False negatives can result, however, from
exposure to everyday environmental conditions such as elevated
temperatures or desiccation, and time sensitivities create
analytical limitations. Additionally, all three bacterial
indicators are highly susceptible to any type of chlorine
disinfection.
Research performed by the Environmental
Monitoring Division (EMD) of the Department of Natural
Resource Protection proposed that Coprostenol, a fecal sterol
specific to human sanitary waste, was a far more reliable
indicator of sewage contamination in environmental samples
than the traditional microbiological methods. EMD's focus was
on the sewage contamination of surface water and waterways in
Florida. Their research proved to be instrumental in
developing analytical protocols and guidelines for the
determination of Coprostenol and other sterols present in
human and animal waste. Aerotech applied the same analytical
protocols to the indoor environmental setting. Results from
Aerotech's Indoor Air Quality (IAQ) investigation were
consistent with those found by the EMD.
The study initiated at Aerotech
Laboratories, Inc. involved the contamination of 6 replicate
carpet samples with influent wastewater from a local
wastewater treatment facility (Category 3 Black Water). A
negative control with no fecal contamination was also analyzed
to show the carpet was free of contamination prior to the
study. The individual contaminated carpet samples were
analyzed over an eight (8) day period to evaluate the presence
and survival of fecal contamination as well as Coprostenol.
At day zero (0) immediately after
application, the bacterial indicators on the carpet samples
were all positive. However, once the carpet samples were
exposed to normal environmental conditions, the microbial
indicators after day zero (0) fell below detectable limits.
The negative results incorrectly implied that the
microbiological quality of the carpet samples was acceptable.
Unlike the microbial indicators,
Coprostenol results remained positive throughout study,
consistently revealing the presence of fecal contamination.
Coprostenol's resistance to typical environmental conditions
provided more reliable data.
