Toxic mold

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Molds are ubiquitous in nature, and mold spores are a common component of household dust.

The term toxic mold is sometimes used to refer to mold-related indoor air quality problems.

Molds excrete liquids or gases as defecatory matter; not all can be detected by smell. Some molds generate toxic liquid or gaseous compounds, called mycotoxins. Of these molds, some only produce mycotoxins under specific growing conditions. Mycotoxins are harmful or lethal to humans and animals when exposure is high enough.

Exposure to significant quantities of mold spores can cause toxic/allergic reactions.

1 Growing conditions
2 History
3 Causes
4 Common molds
5 Symptoms
6 Remedies
7 References
8 External links

[edit] Growing conditions

For significant mold growth to occur, there must be a source of water (which could be invisible humidity), a source of food, and a substrate capable of sustaining growth. Common building materials, such as plywood, drywall, furring strips, carpets, and carpet padding are food for molds. In carpet, invisible dust is the food source (see also dust mites). After a single incident of water damage occurs in a building, molds grow inside walls and then become dormant until a subsequent incident of high humidity; this illustrates how mold can appear to be a sudden problem, long after a previous flood or water incident that did not produce a mold-related problem. The right conditions re-activate mold. Studies also show that mycotoxin levels are perceptibly higher in buildings that have once had a water incident (source CMHC).

[edit] History

Since Biblical times it has been known that indoor mold growth can be a health hazard. (See Leviticus 14:39-47.) In the 1930s, mold was identified as the cause behind the mysterious deaths of farm animals in Russia and other countries. Stachybotrys chartarum was found growing on wet grain used for animal feed.

In the 1970s, building construction techniques changed in response to the energy crises. As a result, homes and buildings became more air-tight. Also, cheaper materials such as drywall came into common use. This combination of increased moisture and suitable substrates contributed to increased mold growth inside buildings.

Today, the agriculture industry keeps a close eye on mold and mycotoxin levels in grains in order to prevent the contamination of animal feed and human food supplies. In 2005 Diamond Pet Foods, a US pet food manufacturer, experienced a significant rise in the number of corn shipments containing elevated levels of aflatoxin. This mold toxin eventually made it into the pet food supply, and dozens of dogs died before the food could be recalled.

[edit] Causes

Because common building materials are capable of sustaining mold growth, and mold spores are ubiquitous, mold growth in an indoor environment is typically related to an indoor water or moisture problem. Leaky roofs, building maintenance problems, or indoor plumbing problems can lead to mold growth inside homes, schools, or office buildings. Another common source of mold growth is flooding.

[edit] Common molds

Aspergillus
Cephalosporium
Cladosporium
Cryptococcus
Fusarium
Harposporium
Mucro
Ostracoderma
Penicillium
Rhodotorula
Trichoderma

[edit] Symptoms

Human bodies can tolerate mycotoxins in small quantities. At what point they constitute a health hazard depends on each individual. Immune system reactions vary; the health effects of mycotoxin exposure include chronic fatigue and irritability, flu-like symptoms, respiratory problems, headaches, cognitive problems, and skin problems. A stressed immune system results in a weakened individual.

Another serious health threat from mold exposure is systemic fungal infection. Immunocompromised individuals exposed to high levels of mold, or individuals with chronic exposure paired with mycotoxin exposure may become infected. Sinuses and digestive tract infections are most common; lung and skin infections are also possible. Alcohol and mycotoxin production may result from the fungal growth, leading to myriad symptoms. Sudden food allergies and digestive problems can mislead diagnosis. Treatment can be long-term (many years). Systemic infection may be of the environmental mold itself, or by other common food-related molds consumed under a weakened immune system. A weakened immune system may also give rise to opportunistic infections, for example bacterial infection.

Environmental illnesses can be difficult for healthcare practitioners to diagnose. Those who are living in houses contaminated by the mold may not be able to smell any odor and may be unaware that the problem exists.

[edit] Remedies

The first step in solving an indoor mold problem is stopping the source of moisture. Next is to remove the mold growth. Common remedies for small occurrences of mold include:

Sunlight
Ventilation
Non-porous building materials
Household cleansers

Significant mold growth may require professional mold remediation and removal of affected building materials. A conservative strategy is to discard any building materials saturated by the water intrusion or having visible mold growth.