Abstract:
Preventative Detection of Stachybotrys Charatum
Brita Roy and Bethany Kerr
Advisors: Dr. Todd Giorgio and Dr. Paul King
April 23, 2002
Abstract:
The goal for our project was to create an early detection device for one of the most common form of household molds known as stachybotrys charatum. We hoped to design a device with an enclosed chemical test that can rapidly identify airborne mycotoxin. Stachybotrys is a fairly recently popularized mold, which accounts for the small amount of research previously done. Our main goal for the chemical test was that it would be and ELISA that was user friendly and very accurate. We wanted the device housing the chemical test to be able to efficiently intake air, open spores and detect Satratoxin H. The final design tests rapidly, is easy to use and has good accuracy and sensitivity. We plan to sell our device for $30/unit with an $8/unit profit. Our device is preferable to the ones currently marketed because it is an early-detection method that will allow for identification before extensive damage is caused by the mold. If able to continue work on the project, we hope to have a working prototype by August 2002
Introduction:
Our project was working on an early detection device for stachybotrys chartarum, which is one of the most common forms of mold found in homes. The illness associated with this mold is known as “sick building syndrome.” The stachybotrys grows on high cellulose, low nitrogen materials that are at least 94% water saturated. As colonies of stachybotrys dry out or are disturbed, the mold releases spores containing mycotoxins. Satratoxin H, the most harmful of the mycotoxins, causes pulmonary hemorrhaging and hemosiderosis when inhaled into the alveoli. Current mycotoxin testing only occurs when the mold is visible or when an inhabitant becomes ill. Most of the current testing also requires samples to be sent to a lab for analysis. Our project was to design a chemical test and a device to house the test that would rapidly identify the airborne mycotoxin. The airborne analysis allows for earlier detection because the mold does not have to be visible.
Literature Review:
We did a fairly extensive literature review. However, since stachybotrys was fairly recently discovered as a threat to humans and homes there has not been extensive research done. Most of the research related to stachybotrys and Satratoxin H was done in relation to agriculture. Stachybotrys has been heavily studied as a mold affecting corn and hay. Satratoxin H has also been studied as a member of the trichothecene mycotoxins. This classification of mycotoxins has been used as biological warfare, and this is where we found most of the concentration data.
The trichothecene mycotoxin affect on humans and chemical data has been heavily discussed in the Medical Aspects of Chemical and Biological Warfare. This class of mycotoxins is nonvolatile and has molecular weights ranging from 250-550 amu. They are insoluble in water, but are highly soluble in acetone, ethyl acetate, chloroform, dimethyl sulfoxide, ethanol, methanol and propylene glycol. These chemical properties of the toxins lead to their effect on humans. In low doses, the toxins can cause skin and eye problems. Severe skin irritation occurs when they are present in nanogram amounts. In lower microgram amounts the trichothecenes lead to sever eye irritation, corneal damage and impaired vision. Aerosolized toxins can cause death within minutes in large doses. Toxin particles larger than one to four micrometers in size are too large to deposit in the alveoli and thus cause hemorrhaging. However, most Satratoxin H particles are smaller than 1 micrometer. When inhaled in larger quantities the trichothecene mycotoxins cause vomiting, diarrhea, skin irritation and blurred vision in the first eight hours. Between 8 and 24 hours the symptoms include burning erythema, blisters, confusion, chills, fever , hypotension and bleeding (Wannemacher).
If Stachybotrys chartarum is found in a building, the California Department of Health Services has published instructions on how to rid of this dangerous mold. In “Stachybotrys chartarum (atra): A mold that may be found in water-damaged homes”, they state that the mold should be treated in different ways according to the area of the mold:
Level I – If area of mold is 2 sq. ft. or less
a) Individuals who have received training on proper clean up methods, protection and potential health hazards can clean the area. These individuals should be free from asthma, allergy and immune disorders. Gloves and a half face respirator should be worn
b) Contaminated material should be placed in a sealed plastic bag before taking it out of the building. This will prevent contamination of other parts of the building.
c) Surrounding areas should be cleaned with household bleach.
Level II – If area of mold is between 2 and 30 sq.ft.
The recommendations are the same as level I, with the added precaution that moldy materials should be covered with plastic sheets and taped before any handling or removal is done. For instance, a moldy panel of gypsum board wall would need to have plastic sheeting taped over the affected area on the wall before the wallboard is cut to remove the contaminated section. Once cut from the wall, that section should be placed within another layer of plastic before it is carried through the building for disposal.
Level III – If area of mold is more than 30 sq.ft.
Personnel trained in handling of hazardous materials are necessary. Specific recommendations for hazardous material workers can be found in the New York document.
Level IV – If Stachybotrys chartarum is found in the heating, ventilation, or air conditioning systems
Recommendations are same as for Level III.
Through our literature search we were able to fully understand the magnitude of this problem and the possible improvement our device could make on the lives of others. Based on the information found in the research we were able to define particular goals for our project and to design a test to properly identify stachybotrys.
Satratoxin H:
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Goals:
• To build a device that would be able to detect Satratoxin H when airborne in Stachybotrys spores.
• The device should detect the mycotoxin before it has reached a high enough concentration to harm the tenants of the home.
• The device should be independent, and should be able to be used by the layman, without any outside lab work.
• The test should quickly detect the presence of Satratoxin H.
Design of Test:
The actual test for the antibody had to be easy to use in the average person’s home, and needed to be both sensitive and accurate. In this test, false positives were better than false negatives. We also wanted to design a test that was relatively fast, and did not require much equipment. The test also needed to detect the toxin in the air, rather than on the mold itself.
We decided to use a biological test to identify the mold, because physical, chemical, and genetic identification all required the mold to be in plain sight, which it usually is not. The single cell calorimeter, BIAcore, and refractive plate mechanisms were all much to expensive for the average homeowner’s use, and were also very complicated. Since we were able to find an antibody to Satratoxin, we decided to use the ELISA test. ELISA antibodies can be easily attached to a strip and tagged to a stain that will change color when the antibody binds to the toxin. This test only takes about five minutes, and we can provide simple instructions for its use.
Final Design:
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Design of Device:
The device had to successfully intake air, open spores, and detect the presence of Satratoxin amongst all other particles in the air. In order to intake air, we decided a fan would be a very simple and cost-efficient way to bring the chemical into the system. The air blown in from the fan is then filtered through a mesh screen that blocks particles larger than the spores from getting into the system. The screen can be easily removed and cleaned to prevent buildup and blockage of the system.
Since the mycotoxin is encased within the spores of stachybotrys, we had to find a way to break them open. Because the spores are so small, mechanical methods proved to be difficult. So we chose to open them chemically with a protease lysis buffer. This buffer eats away the cellulose casing of the spores, while leaving the chemical toxin intact for testing.
So the filtered air taken in by the fan will be blown onto a sponge saturated with the lysing buffer. The buffer should break the spores apart, and the user can then depress the button on the top of the device, squeezing the contents of the sponge into a reservoir. We chose to have the solution squeezed into the reservoir rather than testing the sponge itself because this was safer for the user, since they never have to come into direct contact with the toxin.
Once the solution has been emptied into the reservoir, a pre-made antibody-coated strip can be dipped into the solution through a slit in the reservoir cup. After about five minutes, a color change will be visible on the strip if the antibodies detect the mycotoxin. This type of test has been proven to be easily used in the home, as many people use this type of color-change ELISA in a home pregnancy test.
So our final design achieved our entire goal: rapid testing, easy to use, and accurate and sensitive.
Economic Analysis:
Industry research has shown that anywhere from 4-50% of American homes are in danger of being contaminated by stachybotrys. The mold is found in all areas of the country with reports of outbreaks in Texas, Ohio, Washington, Florida and Tennessee. Our product will have a more universal appeal because it is portable, easy to use, and gives immediate results unlike the current tests available (see appendix). We estimate that 2% of American homes may actually buy our product with corresponds to 2 million units. Our development cost should be fairly low. We are hoping to obtain the antibody and reagents at no cost. The intellectual development cost should be approximately $15,000 for 2 students at $15/hr. The parts for the design are very simple and should not cost more than $10/unit. With marketing and overhead the overall cost for the unit should be $22/unit to build and market. This would leave us with $8/unit or 16 million dollar profit.
Our device is beneficial for the user because current testing methods require samples of visible mold to be sent to a laboratory. If the mold is stachybotrys, then the homeowner faces an average of $10,000 in repair and removal. In some cases the homeowner may have to leave their home completely. Our test is an early detection method that would be able to identify the mold before it’s had the chance to proliferate to a great extent, which would decrease the repair and removal costs. In addition early detection decreases the probability that the homeowner will have to abandon their residence. The test would be designed for one-time use and would have no maintenance costs. However, the test could be made to be reusable, which we may consider after further analysis. However, to minimize risk, a professional may have to reset the test. The risk associated with the test is minimal after precautions are in place and would not be considered an economic burden.
Overall the device seems to be profitable for the manufacturers and cost saving for the homeowners.
Design Safe:
Our Design Safe analysis was very thorough as can be seen by the full analysis in the appendix. Our initial risk analysis contained several high-risk hazards that were mostly concerned with the chemicals in the test and the hazardous waste resulting from the test. However after adding risk reduction methods, the hazards were all of low to moderate risk. Many of the hazards analyzed in the analysis have a very low probability of occurrence, such as fire caused by dust in the fan. However, the toxicity and chemical reaction associated with the testing materials is a very serious concern. Most of the protections considered in the Design Safe analysis would be designed as we continued to design the product. We plan to make the device as leak-proof as possible to minimize the chance of exposures to the chemicals or hazardous waste. The actual chemical nature of the buffer, solution and solvents used in the tests has not yet been determined. As further testing is done, the Design Safe analysis will have to be revamped to include or remove unnecessary hazard analyses.
Conclusions:
We plan to get a prototype of this device built and tested by August, 2002. If this device can successfully work, it could save millions of dollars in repairs for homeowners in the United States alone. It could also help farmers, who have been struggling with the effects of Stachybotrys infested hay for years. Insurance companies may use this device as a mandatory part of home inspections.
This form of early detection will not only save property-owners money, but it will also save money in healthcare. Prevention of Stachybotrys growth will mean that fewer children will have to be hospitalized, and fewer adults will be treated for allergy-like symptoms.
Finally, our product will help save lives. Since pulmonary hemosiderosis is potentially lethal in infants, it may be able to save the premature death of our young ones. Although “sick-building-syndrome” is not very well explored, it is proving itself to be a deadly menace to our health.
Recommendations:
We strongly recommend that this design continue to be researched and developed. The current design is theoretical, and will need to be physically tested for sensitivity and accuracy. If the device can be successfully marketed, the economic gains will be quite high, as will the benefit for the health of the public.
Bibliography:
Ammann, Harriet M. “Is Indoor Mold Contamination a Threat to Health?” . January 23, 2002.
“Health Effects of Toxic Mold,” . March 11, 2002.
Smith, Pat. “Family’s Dream is Shattered by Toxic Mold,” Bulletin. . January 23, 2002
“Stachybotrys charatum (atra): A mold that may be found in water-damaged homes,” An Infosheet produced by the California Department of Health. April 1997. . January 28, 2002.
Wannemacher, Robert W. and Stanley L Weiner. “Chapter 34: Trichothecene Mycotoxins,” Medical Aspects of Chemical and Biological Warfare. P 655-76.
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