Many common molds found indoors in Hawaii (aspergillus, cladosporium, penicillium ), have cell walls with an outer-layer of chitin. In most molds chitin is the largest single component of the cell wall. Chitin is a polysaccharide (C8H13NO5) p which makes up the exoskeleton of arthropods (crabs, ants, spiders, etc.) , and as mentioned before numerous molds.
Now while its interesting that “bug” and mold “shells” have a commonality , what’s significant about chitin? According to Dr. Locksley from the University of Calfifornia, San Francisco conducted research that determine that exposure to chitin triggers a an allergic inflammatory response in the lungs of mice. Similar repsonse to chitin in humans are well documented , particularly workers shelling and processing crabs::
Dr. Locksley points out, “The snow-crab industry is a big part of a seasonal industry up in Alaska and Canada [and snow crab shells are rich sources of chitin]. College kids come in and they work in these crab processing plants. It’s the food industry, so the first thing they do is get all the bacteria out of the environment by using microbicides. Then you’ve got these kids in there pulverizing chitin shells for hours on end. The attack rate for new onset asthma in that industry is something like 25 to 28 percent per year. It’s now a major cause of disability in Canada.”
The UCSF research found that the lab mice increased production of chitinase (an enzyme that breaks down chitin) with exposure. Humans also produce chitinase in response to allergies.
“It turns out that a disproportionate number of people who have asthma have this [variant of chitinase],” says Dr. Locksley. “So another potential issue is whether kids with a variant are at particularly high risk when they go into these environments, such as a home that might be moldy or have a lot of dust mites.
excerpted from:http://pub.ucsf.edu/today/feature.php?news_id=200704205&submit=PREVIEW&preview_date=2007-04-23
More research needs to be conducted to determine what if any role environmental chitin present in indoor air plays in allergic response. If a positive correlation is determined though, it presents a potentially useful metric in screening buildings or conducting clearances after a mold remediation.
In addition to mold investigations, I perform asbestos inspection, oversight, and project monitoring– which includes air sampling. After an asbestos abatement is conducted air samples are collected to determine the amount of asbestos fibers or structures remaining in the air and dust (agressive method/mechanical air agiation during sampling). In order for an asbestos abatement to be considered successful and complete, onr of the criteria is that the concentrations of asbestos in the post removal air samples must not exceed specified values. It is conceiveable that a permissible exposure limit , or some sort of threshold concentration could be derived for chitin.
During the investigation or after the remediation phase, an hygienist could collect air samples to measure the chitin concentrations in the air. If the primary concern in a specific mold investigation is allerigic response by a building tenant(s) then it could either provide a target for response actions (or at worst aid the investigator in identifying the cause). By comparing the measured value to some guideline (along with visual inspection , and perhaps other sampling) it could allow for a meaninful determination of the success or failure of the action.
Even the initial findings provide some caution to mold remediators. “Killing” mold growth alone may not be adequate to minimize potential health risks to building occupants. Unless the mold and celluar fragments are removed a potential source of allergens may remain in the environment.
Tags: Allergies · Asthma · Chitin · Mice and Men · MoldNo Comments
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