What is Mold Contamination?

What is microbial contamination? Where does mold come from? Is mold contamination a health concern issue? How do you properly get rid of mold?  These are just some of the questions home and business owners ask when they find out they have a mold problem.

Microbial contamination refers to a variety of microorganisms, including mold, bacteria, viruses, and protozoa; and fungi, which include molds, yeasts, and their byproducts and toxins. All of these can affect the health of a building and its occupants.

In this paper, we will begin by answering the question: what is mold contamination? A full discussion of related issues will follow in subsequent papers released by Metrix Restoration. As a starting point, the proper job sequencing for a typical mold remediation project includes but is not limited to: identifying and stopping the source of moisture; setting up containment; establishing negative air; removing contaminated building material; cleaning surfaces; drying the affected area; and conducting post remediation evaluation. The IICRC S520 defines mold contamination as any non-condition 1 indoor environment.

Condition 1: a normal indoor living environment. This is the normal indoor living environment that one would expect in a home, office building or commercial building.

Condition 2: an indoor environment that is contaminated with settled mold spores and fragments. This could be an area that is located near active mold growth, but does not have active mold Itself. For example, the room adjacent to an effected area may not have active growth, but could have settled mold spores originating from the effected zone.

Condition 3: an indoor environment contaminated with visible or active mold growth.

Mold Contamination Begins With Water Damage

Almost all plants and animals need light, but both fungi and bacteria do not because of their method of obtaining energy. In all forms of life, as we know it on earth, water is a requirement. Thus, if a building stays dry, no form of life can live on it. This means that if buildings are kept dry, mold and other bacteria would not become an issue effecting the living space of a home or an office.

When water enters a building in any form the potential for microbial growth to become established is solidified and potentially increases with time.  Many types of contamination affect homes. Some of these contaminants are beyond the scope of this paper. The primary types of microbial contamination that this paper covers are molds. Microbial contaminations include microscopic particles and spores that need water to survive and proliferate. All living organisms on earth need water to survive. While spores can exist in all buildings, a wet building is almost certainly going to contain spores, and these sports will lead to mold growth.

One of the easiest ways to determine if a building has a mold problem is by odor. Odors detected in water damaged buildings can be caused by wet structural materials. The odors released by microbial growth are musty or earthy odors and are scientifically known as microbiological volatile organic compounds.

Spores Are A Major Concern For Mold Remediators

Mold spores are a major concern for remediators because of their very small size. Mold spores can be anywhere there is air, including under carpet, inside wall cavities, under kitchen cabinets, virtually everywhere. Most are usually not a problem unless mold spores land on a damp spot and begin growing. They digest whatever organic material they grow on to survive. Some molds grow on wood, paper, carpet, foods, and insulation, while other molds feast on everyday dust and dirt that gather in the moist regions of a building.

Generally, molds are hydrophobic. This means that spores do not like water itself. While mold spores need water to colonize, they like wet organic substances, not a puddle of standing water. These airborne mold spores are looking for a proper location to reproduce. The location must provide food, water, and a calm environment, preferably darkness and acceptable temperature. The inside of a building wall cavity is perfect, except that wall cavities are normally dry. Simply add water, allow the area to stay wet for a few weeks, and mold grows.

Mold starts from a spore. Once the mold finds an acceptable environment, growth starts. Mold grows into a plant like structure having a network of tubular branches called hyphae. Hyphae are genetically identical and are considered a single organism or a grouping called mycelium. Once mold becomes visible to the human eye, this grouping is then called a colony. In most residential and commercial water damage, mold remediation becomes a standard after 72 hours.

As colonies of mold continue to grow, they reach a point where it becomes time to continue their life cycle. This is when mold begins to produce and release spores into the environment, known as sporulation. Two types of spores are produced during sporulation: viable spores and non-viable spores. Viable spores are active and can establish new colonies. These types of spores may also be allergenic, and or contain toxins. Non-viable spores are not active and therefore cannot begin new colonies. The term settle spores refers to those spores which are present on surfaces but are not active. This distinction is necessary for defining conditions of mold contamination.

Mycotoxins are released by molds as part of their natural defense system.  Humans are also sensitive to mycotoxins produced by mold and are subject to related health effects.  Among the most common mold types encountered by mold removal professionals are Stachybotrys, Aspergillus, and Penicillium.  Stachybotrys requires a constant water source to thrive, in other words, a very moist environment.  Unlike Stachybotrys, both Penicillium and Aspergillus are able to grow in low moisture environments. Mold does not “die” when a structure dries out, it simply goes into a “dormant state”.  This is why non-salvageable materials are disposed of during a mold remediation project and structural materials such as studs and joists are dries and decontaminated.

Mold VS Mildew

The words mold and mildew are often used interchangeably, but they are distinct species within the fungi family. Mold is one of nature’s chief decomposition mechanisms. Molds that decay dead organic matter that was once alive, such as trees, leaves, cotton, leather, wolves, are known as saprophytic molds. Molds are part of the natural environment.  Molds are fungi that can be found both inside or outside throughout the year. The problem with saprophytic mold is that it does not understand the difference between a dead tree and the forest, and a two by four wall stud that came from a dead tree and a home, that we do not want decomposed.

Indoors, mold growth should be avoided. Problems may arise when mold starts eating away at materials, affecting the look, smell, and possibly, with respect to wood framed buildings, the structural integrity of buildings. Mold reproduces via a very small seed, called a spore. Mold spores are very small and are typically found to be 2.0 Microns in diameter. Because of this very small size, mold spores are invisible to the human eye, and are everywhere there is air. Most can grow on virtually any substance or material, if moisture or water, oxygen, and an organic food source is present. Molds reproduced by creating tiny spores that cannot be seen without magnifying them through a microscope. Mold spores are very similar to dandelion seeds as they continually float through the indoor and outdoor air using air currents as transport.

Biohazard & Fungal Clean Up

Whenever human and or animal biological wastes or fluids are involved in a mold removal project, the project also becomes a biohazard cleanup.  Mold removal professionals should also be aware that any mold remediation involving bird or bat droppings may also involve cryptococcus neoformans and histoplasma capsulatum which are known to cause serious respiratory disease.  Mold remediators should also take special precautions when conducting inspections or mold removal projects involving any rabid animals.