The Mystery of Mycotoxins in Mold Contamination

The Mystery of Mycotoxins in Mold Contamination

By Michael A. Pinto, CSP, CMP and Steve Levy, CIEC, CMC

The role that mycotoxins play in the big picture of people suffering health effects when they occupy water-damaged buildings (WDB) has been investigated for decades. In 1966 Harriet Burge, one of the early and longtime industry leaders in the field of fungal contamination, developed a risk assessment for reviewing indoor mold contamination situations, which incorporated both the known allergic and poisonous (mycotoxic) characteristics of mold. Burge’s model indicated that most indoor mold growth is not extensive enough to result in a level of mycotoxins sufficient to produce deleterious health effects. In the intervening years this assessment has been challenged on many fronts, with recent medical, analytical, and anecdotal data encouraging professionals to take another look at the problems associated with cleaning water-damaged buildings.

Basic Science as a Starting Point

Many people are aware that water damage in buildings leads to a variety of bad outcomes. Water-impacted building materials and contents provide an environment where a variety of organisms can flourish. Bacteria, fungus, and even viruses can not only survive but reproduce on damp or wet materials. Obviously, being exposed to such organisms can potentially contribute to health problems for the occupants. Numerous national and international agencies (including the National Institute for Occupational Safety and Health, the Centers for Disease Control and Prevention, the World Health Organization, Britain’s National Health Service, and many others) have put out information warning of the possible ill health effects from occupying damp and moldy environments.

Despite this consensus that water-damaged buildings can be harmful, there is not nearly as much agreement regarding the exact causes of the problems. While researchers know that microbial growth in a building can hurt people in a variety of ways, the exact process of how the illnesses occur still eludes scientists. Fungal infections of both skin and internal systems are well known—but fortunately are rare. The growth of many microorganisms produces microbial volatile organic compounds that can be irritating to the eyes and respiratory tract. The allergenic nature of mold spores and other pieces of fungal organisms (generally lumped into the term “hyphae”) is also well recognized, although most allergic reactions are thought to be short-term. The really controversial health concern is whether the mycotoxins produced by molds can be poisoning people in such an environment or causing some other sort of reaction.

The reason that mycotoxins are suspected of poisoning people is based on both science and observational connections. “Mycotoxin” is the term that scientists use for a variety of chemical compounds that are produced by fungi during their growth cycle (the official term for mycotoxins is “secondary metabolites”). The suffix toxin is found at the end of the word mycotoxin because a great number of these mold-produced chemicals have been proven to be poisonous to both insects and animals—including people.

The Recurring Concern About a Health Connection

Given that many people living in water-damaged buildings have reported symptoms that would seem to reflect some sort of poisoning (such as digestive problems, malaise, neurological impairment, and extreme fatigue), much attention has been focused on the naturally produced poisons from the fungus as a possible source for the symptoms. Despite the seemingly obvious connection, numerous scientific reports concluded that the amount of mycotoxins actually making it into the bodies of occupants who spend time in a water-damaged and moldy environment would be too small to cause symptoms. A 2011 article for EMLab by Dr. Burge stated:

The fact remains that no research has documented that anyone has ever been exposed to enough mycotoxin from exposure to indoor fungal growth to actually cause any of his/her symptoms with the possible exception of agricultural environments.

This sentiment was echoed by Dave Gallup, the chairperson of EMLab, in an article written for the National Association of Moisture Management, entitled Health Risks Due to Inhalation of Fungal Mycotoxins. In that piece he actually put together a formula that included the minute amounts of mycotoxins that are present on spores or hyphae, the number of spores and fragments that are in the air in a water-damaged building, how much a person breathes, and a calculation of the number of breaths necessary to get a dose of fungal poisons at a level that could be dangerous. His calculations showed that individuals would need to be in a significantly water-damaged structure for over 1,000 days to reach a level that could even potentially cause health problems.

Despite these scientific calculations and many other similar evaluations, it was difficult for the remediation professionals and occupants who were sickened by water-damaged buildings to accept that mycotoxins were not playing a part in the suffering that was observed in such situations. As the information from calculated potential exposure amounts was studied more closely, concepts from allied fields were used as a better model. In particular, the concept of “total body burden” developed for lead dust exposure was seen as being applicable to mycotoxins, as well. Mold remediation professionals and ill occupants understood that living in a water-damaged structure resulted in numerous types of potential exposures—not only inhalation of airborne spores and mycotoxins. As the lead remediation professionals learned, small particle contamination in a house results in ingestion and possible skin absorption as well as inhalation. All three potential routes of entry must be evaluated in order to get a true picture of the potential risk.

In addition to the potential for exposure through different routes of entry, scientists as early as 2000 were speculating that mycotoxins from different types of molds may need to be evaluated as part of the understanding for why some individuals in water-damaged buildings suffer such a variety of ill health effects. One report, entitled A risk assessment model for mycotoxin-producing molds on human health in indoor environments, offered this provocative assessment:

Since the modes of activity of trichothecenes differ from aflatoxins and other mycotoxins, the combinations of mycotoxins could be additive or even synergistic, which could significantly reduce the amount of either mycotoxin required to induce an immunosuppressive or toxic effect. Immunosuppressive and combinational effects of multiple mycotoxins may constitute major components in the adverse health effects reported by many of the victims of mold exposure.

Sampling Limitations

Understanding that mold and mycotoxin exposures could occur in a variety ways, the scientific community worked to improve sampling processes. Cassette style spore trap air samples dominated the mold inspection and remediation industries within a few years of their introduction. Detection of molds based on DNA (quantitative polymerase chain reaction analysis known as qPCR) expanded dramatically after EPA scientists developed a process for determining, from a single carpet sample, if a home had a history of water damage. Still, improved methods to detect mycotoxins lagged behind.

In many respects it was not until 2007 when advances in the detection of mycotoxins started to accelerate. That year Erica Bloom from Lund University in Sweden published a report titled Mass Spectrometry-Based Strategy for Direct Detection and Quantification of Some Mycotoxins Produced by Stachybotrys and Aspergillus spp. in Indoor Environments. That same researcher followed up with a survey a few years later, entitled Molds and mycotoxins in indoor environments—a survey in water-damaged buildings, which offered some insightful conclusions:

• Molds in water-damaged indoor environments, in both sub-tropic and tempered climatic zones, produce mycotoxins regularly. Mycotoxins were found in settled dust on surfaces above floor level indicating that mycotoxins from mold contaminated building materials can become airborne and inhalable.
• Mycotoxin production or prevalence does not seem to correlate to microscopy findings, CFU counts, or PCR results for fungi. There is a potential correlation between fungal biomass and mycotoxin production.

 
Over the next few years both the ability to analyze samples for mycotoxins and the availability of laboratories to conduct such sampling at a reasonable price improved. Today, while still relatively expensive, mycotoxin testing is moving more directly into the mainstream of investigations of water-damaged buildings—especially in cases where more traditional sampling approaches do not provide satisfactory answers.

An Example from an Actual Project

A number of consultants and investigators are starting to add mycotoxin testing to their protocols, particularly when more standard investigative techniques do not provide answers to the problems. In one well documented case the home owner was a 64 year old man who complained of chronic sinus and respiratory issues while in his home. The symptoms subsided when he left the house for an extended period of time. His children, who are adult age and do not live with him, noticed that every time they visited they left the home with a musty smell on their clothes. All of this resulted in an inspector being called to the home in February of 2014.

Mold contamination was detected in the basement, ambient living areas, and the attic. Although the HVAC system, located in the basement, had been replaced a few years prior to the inspection, the ductwork was the original material installed in the home approximately 30 years earlier. Air and surface sample results confirmed that the worst problem was in the basement. Those results were supplemented by qPCR sampling of the ductwork that showed a total of 44,149 group one spore equivalents (i.e., mold types associated with indoor water damage) present in the swab sample collected from inside the HVAC system. Source removal was conducted, although the homeowner elected to contract for “standard” duct cleaning rather than a more expensive approach where the mechanical components would be removed and cleaned in conjunction with the cleaning of the ductwork.

Spore trap air samples and surface samples were collected following the remediation work, although not from the HVAC system. Based on those results the remediation was deemed a success. However, about a month after the completion of the remediation work the homeowner was still experiencing symptoms, with the important distinction that the symptoms escalated when the HVAC system was operating. Testing of the HVAC system showed very low airborne spore concentrations and a swab sample analyzed by the qPCR technique showed that the group one spore equivalents had fallen from 44,149 to 282.

Despite the seemingly clean sample results, the HVAC system was cleaned a second time; and this time the motor was physically removed for a more thorough cleaning (but the coils were not). Following this round of cleaning the group one spore equivalents inside the HVAC system jumped up to 3,087. A side-by-side wipe sample for mycotoxins detected a relatively high amount of trichothecenes—the poison most commonly associated with Stachybotrys mold—despite the fact that no Stachybotrys spores had been recovered in the qPCR sampling.

A third cleaning of the ductwork occurred, although the decision was once again made to try clean the coils in place rather than remove them from the housing of the HVAC equipment. Follow-up sampling showed group one spore equivalents virtually unchanged at 3,066, although the amount of trichothecenes recovered was halved. This time, Stachybotrys was recovered in the qPR sampling.

While the homeowner was satisfied after the third cleaning, despite the documented presence of group one spore equivalents and mycotoxins, the experience led to some interesting conclusions:

• Mold spore concentrations used in clearance protocols do not guarantee that, even at those levels, the environment is cleaned of mycotoxins.
• Due to the difficulty of access, it is improbable that an HVAC system and associated ducts and returns can be thoroughly cleaned once they have become contaminated with mold and mycotoxins, unless the mechanical components are removed from the housing for more thorough visual inspection and cleaning.

Moving Steadily Toward Solving the Mystery of Mycotoxins

As in many cutting-edge technologies, our ability to collect data often outstrips our ability to properly interpret the information. As mycotoxin testing becomes more prevalent in our industry the typical, but crucial, questions that are asked in regards to any indoor contaminant will need to be answered:

1. What is a normal level of mycotoxin contamination in a structure?
2. What is a safe level of mycotoxin contamination in a structure?
3. Does the answer to Question 2 depend on the type of mycotoxins present?
4. Does answer to Question 2 depend on the type of occupants present?

 
As always, these questions will be answered by a combination of field practitioners and researchers. In the meantime, cleaning and restoration contractors need to be aware that mycotoxin contamination and testing is a new wrinkle in the industry that needs to be considered as they work to assist individuals in water-damaged buildings with fungal contamination.

About The Authors

Michael A. Pinto, CSP, CMP, is chief executive officer of Wonder Makers Environmental, Inc., a manufacturing and environmental consulting firm that specializes in identification and control of asbestos, lead, IAQ, mold, industrial hygiene, and chemical problems. Mr. Pinto is the author of over 200 published articles and several books, including Fungal Contamination: A Comprehensive Guide for Remediation. He holds numerous certifications in the environmental and safety areas including Certified Safety Professional and Certified Mold Professional. Michael has been honored with such prestigious awards as the Golden Quill, Martin L. King Award, the Phoenix Award for Innovative Restoration from the Restoration Industry Association, and the President’s Award from the Environmental Information Association. He serves on the board of the Indoor Air Quality Association (IAQA) as well as the Cleaning Industry Research Institute (CIRI), and as the chairperson of the Environmental Council for the Restoration Industry Association (RIA). Michael can be reached at 269-382-4154 or “map at wondermakers.com”.

Steve Levy is the founder and president of Certified Mold Inspections, Inc. (CMI), which focuses on assessing possible moisture or water intrusion that can result in microbial contamination. He has performed well over 3,500 mold specific investigations/inspections and testing projects. Steve holds numerous certifications within the indoor air quality industry. Through the ACAC he is a Council-certified Indoor Environmentalist (CIE), a Council-certified Microbial Consultant (CMC) and a Council-certified Microbial Remediator (CMR). Steve holds a Bachelors of Science degree from Northern Illinois University. He can be reached at 732-203–0885 or “steve at moldtestingnj.com”.

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— Mold Sensitized (@moldsensitized) July 16, 2015