Volume 43 Number 10
On Tap: A Fungus Among Us -- An Inside Look at the Mold Issue in Homes
In the point-of-use/point-of-entry (POU/POE) industry, questions frequently arise regarding the relationship of pathogenic fungi and drinking water. Although fungi are ubiquitous in the environment -- found in soil, air and water -- drinking water is typically not a direct link to pathogenic fungal infections but rather an indirect contributor, since water is a key ingredient in the successful proliferation of the organisms.
Background on fungi
Most fungi reproduce via the production of microscopic spores, from which branching structures, or hyphae, develop. Atop the hypha, a cup-like structure -- known as the sporocarp -- holds the reproductive mass of spores. Fungal spores vary in size from 1 to 100 microns and enable fungi to survive harsh conditions whether they travel or lie dormant. Spores are very lightweight and can easily be dispersed by air. Fungal spores are common in the environment, averaging approximately 1-to-2 × 104 per cubic meter of outdoor air, varying greatly due to season or geographical location.
Fungi are also beneficial organisms, used to make medicines and industrially important chemicals or serve as an indirect or direct food source. Relative to the number of fungi identified, few are pathogenic to animals, plants and humans. Approximately 200 fungi are known to cause diseases in vertebrates.
Prevalence of indoor molds
Molds are known to cause a variety of health effects, including mild skin infections to severe allergic reactions to lung disease, cancer, organ failure, neurological disorders and death. In addition, molds are also suspected of being associated with Sudden Infant Death Syndrome (SIDS), stillbirths, infertility problems and hormonal imbalances (see Table 2). Many fungi are problematic whether the organisms are living or dead. Mold toxins are so potent that most of the research in this area has been conducted by the U.S. Department of Defense due to the concern for their use as biological warfare agents.
The most common health effect of mold is allergic disease. Allergic diseases have greatly increased worldwide over the last 30 years. More than 50 million Americans (or about 20 percent of the total population) suffer from hay fever, asthma or other allergic diseases. The allergy and asthma “epidemic” costs an estimated $6.5 billion in medical and indirect costs with $3.5 million to lost workdays and $2 million to school days each year. Adverse effects associated with mold may be immediate or delayed for years. Almost all microbial allergens are fungal in origin and any one fungal species may produce dozens of allergens.
The most common indoor molds are Cladosporium, Penicillium, Aspergillus (primarily associated with allergic reactions, headaches, itchy eyes, rashes and respiratory problems, but also known to produce mycotoxins, resulting in chemical toxigenic responses). Perhaps the most disconcerting indoor mold is Stachybotrys chartarum (aka S. atra). This mold, even in small doses, is associated with severe, often irreversible neurologic conditions, lung disease and death. Currently, there’s no accurate information about how often Stachybotrys chartarum is found in buildings and homes. While it’s less common than other mold species, it isn’t considered rare.
Everyone is potentially at risk of pathogenic fungi and many fungal infections don’t respond to treatment and can have fatal consequences. In addition, immunocompromised populations (i.e., children, elderly and the chronically ill) are at increased risk for mold infections and a more serious outcome of disease. Early exposure of children to molds may predispose them to chronic health problems in the future.
Minimizing mold exposures
Although the U.S. Environmental Protection Agency (USEPA) has consistently ranked indoor air pollution among the top five environmental risks to public health, there are currently no federal regulations or standards for airborne mold contaminants. Indoor mold and moisture represent a public health issue that’s inadequately addressed by building, health or housing codes.
As a rule, fungal growth in homes or businesses shouldn’t be ignored and measures of removal and decontamination need to be applied at the first sign of contamination. The most important primary need for elimination of mold in buildings is to remove the moisture source and reduce the contaminant via routine cleaning and disinfecting.
In more than 65 percent of surveyed homes in the United States, residents report they live in a damp environment. Dampness has been a significant factor in the prevalence of respiratory and other illnesses in children. Preventing a home from becoming moldy is far easier (and cheaper) than trying to eliminate a fungal colonization. A 10 percent household bleach solution appears to be sufficient for disinfecting mold on indoor surfaces. Numerous commercial products are also widely available for disinfecting molds on non-porous surfaces. Carpeting and other porous material should be carefully removed. Exposure to molds during remediative procedures can be 10-to-1,000 times higher than background levels. In severe situations, respirators and protective clothing may be necessary. Rapid cleanup of water-damaged homes can help to minimize the growth and spread of fungal contaminants as can routine and diligent house cleaning.
About the author
Table 1: Sources of indoor moisture
Problem Sources........................Common Sources
Flooding...............................Steam from cooking
Table 2: Symptoms associated with pathogenic mold
Shortness of breath.....................Immune suppression
EXTRA: Mold discovered in bottled water