Dr Jackson Kung'u- Mold Specialist

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Dr. Jackson Kung’u (PhD)- Mold Specialist.
Phone: 905-290-9101

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Aspergillus/Penicillium in the Basement

Question: Is Aspergillus/Penicillium spore count in the basement high? We have this smell in our house for some time. We have also arranged for the gas company to come to see if there is gas leak. Last week, we had an air sample taken from our house. The Aspergillus/Penicillium reading from outside was 267 spores/m3 and the reading from the basement was 26,667 spores/m3. I do not know if these readings indicate any significance. Do you have any suggestions for the cause and solutions? Thank you very much for your help.

Answer: I think the Aspergillus/Penicillium spore count in the basement suggests persistent humid conditions. You may want to hire a professional to come and assess the extent of mold growth in the basement, identify the cause (i.e., moisture source) and suggest the best method to fix the moisture problem and remove the mold safely. To control the growth of mold such as Aspergillus/Penicillium the humidity in the basement has to be reduced to a level below 60%. The following techniques can help control moisture in the basement:

  1. Fix leaks, drips, and seepage problems.
  2. Dry wet areas within 24 to 48 hours to prevent mold growth. Thoroughly clean and dry water-damaged carpets and consider removal and replacement of items that appear to be permanently water damaged. Mold and mildew on hard surfaces can be washed and the surfaces dried completely.
  3. Do not finish a basement below ground level unless all water leaks are sealed. A finished basement should also have adequate outdoor ventilation and heat to prevent condensation.
  4. Operate a dehumidifier in the basement, if necessary, to keep relative humidity levels down. But keep in mind a dehumidifier can be expensive to operate.

Stachybotrys – The Black Mold Demystified

Since the 1993-1994 unusual outbreak of pulmonary hemorrhage (lung breeding) in infants in Cleveland, Ohio, that was then thought to be due to  exposure to Stachybotrys, the health effects associated with this mold have remained controversial. Frequently referred to as the Black Mold by the general public, Stachybotrys has probably caused more economic and psychological agony than ill-health. The mold has resulted in multimillion dollar remediations and litigations.

Stachybotrys was first associated with death of horses in Eastern Europe in the 1930s. Horses fed with hay contaminated with Stachybotrys were reported to surfer from a disease characherized by irritation of the mouth, throat, and nose; shock; dermal necrosis; a decrease in leukocytes; hemorrhage; nervous disorder; and death.

While Stachybotrys is so much feared the number of cases where it was the cause of ill-health or death are insignificant compared to some other toxigenic molds such as Aspergillus flavus or Aspergillus fumigatus. There are about 15 species of Stachybotrys but the most well known is Stachybotrys chartarum. Stachybotrys chartarum is sometimes erroneously referred to as pathogenic mold. When encountered in buildings it’s a serious problem for homeowners, building managers and remediation contractors who must deal with the human issues and remediation. The presence of a single spore in an air sample is enough for some professionals to declare the remediated building unfit for human occupancy. Currently there is no scientific evidence to support such a decision. Perhaps such decisions are driven by fear of liability, fear of being sued by someone who may later believe they were sick because the building was found to have a few spores of Stachybotrys when they occupied it. It’s time the scientific community demystified Stachybotrys, the black mold, for everyone’s peace of mind.

Should you have a question on Stachybotrys please contact us at 905-290-9101 in Ontario or 604-435-6555 in British Columbia.

References

1. Stachybotrys chartarum: The Toxic Indoor Mold.

2. Indoor Mold, Toxigenic Fungi, and Stachybotrys chartarum: Infectious Disease Perspective.

How To Get Rid Of Mold Growth

Many people and even institutions would be happy if they could find a way of getting rid of mold. Unfortunately it’s almost impossible to get rid of mold completely. However, if we understand the conditions that support mold growth, we could then try to manipulate those conditions so as to control mold growth. Mold growth has the following requirements:

1. Presence of spores or mold fragments that are capable germinating (viable) and developing into new mold growth.

2. Moisture. Like any other living organism mold requires water for growth.

3. Nutrients. Nutrients are readily available as some components of building materials are made of easily degradable organic materials. Nutrient are also available in dust.

4. Suitable temperature. For most indoor molds the optimal temperature for growth is between 20 and 25 oC.

The last two mold growth requirements would be difficult to manipulate. As mentioned above some materials in buildings are readily degradable by microorganisms. As for the temperature, mold can grow at a wide range of temperature and it’s optimal temperature is similar to that required in buildings for human comfort.

To control mold growth, therefore, we need to try and reduce or eliminate spores/mold fragments and water in our buildings. We could reduce the amount of spores and/or mold fragments settled on interior surfaces in buildings by HEPA vaccum cleaning all surfaces that are prone to dust on a regular basis.

To be able to control moisture, we need to understand the sources and also the mechanisms by which moisture moves through the building. The primary sources of moisture in buildings include:

1 . Liquid water, from precipitation (rain and melting snow) or plumbing leaks;

2. Water vapor (condensation), from the exterior and from activities and processes within the building;

3. Liquid and vapor from the soil adjoining the building;

4. Moisture built-in with materials of construction or brought in with goods and people

 Controlling moisture in the building may require the help of a professional who understands the processes by which moisture moves in and through the building. To completely get rid of mold growth in a building is difficult.

 

Mold Exposure Limits

Question: My question regards mold exposure limits. I just had a mold count done in my home. The spore count levels in the basement were 5X and 6X outside air in the bedroom. Are these levels high enough to make someone sick? What are “high” levels? In other words are there mold exposure limits? Molds found were Penicillium, Aspergillus and ascospores. I spent a good deal of money on the testing and just would like someone else’s point of view, other than the guy wanting to sell me the remediation. Thank you.

Answer: Due to the large number of mold species and strains commonly found in buildings and the large inter-individual variability in sensitivity to mold exposure it has been difficult to set mold exposure limits. In other words there are no safe or unsafe levels of airborne mold spore counts that have been established. In absence of mold exposure limits, results from tests for airborne fungal spores cannot be used to assess risks to the health of building occupants. However, individuals who are immunocompromised are at higher risk of mold exposure than healthy individuals.

To minimize the risks of mold exposure it’s recommended to:

  • control humidity and diligently repair any water damage to prevent
    mold growth; and
  • clean thoroughly any visible or concealed mold growing in
    residential or office buildings.

These recommendations apply regardless of the type of mold found to be growing in the building.

Quick Take 15

Question: How long is the time needed by Quick Take 15 apparatus for detection of mould? Is there any incubation time needed after the sampling step? Or is the detection system different from culture followed by DME. In fact I am looking for a rapid detection system for Cladosporium.

Answer: Quick Take 15 is used for collection of air samples for fungal spore counting and identification. It’s designed for short sampling times (1-15 minutes) for airborne particulates including mould spores. It’s ideal for use with Air-O-Cell, VersaTrap, and Allergenco cassettes. Samples collected with quicktake 15 do not require incubation and hence you could use it for rapid detection of airborne spores and other particulates. Results can be obtained within the same day.

If you require identification of the moulds to species, then you need to use Quick Take 30. Quick Take 30 uses agar plates. After sample collection, the samples are sent to a laboratory for incubation and species identification and enumeration. It takes between 10-15 days (or more) to get the results.