Monday, January 14, 2008

Indoor Air Quality - Mold Sampling

BIOAROSOL: GENERAL INFORMATION

Bioaerosols are airborne particles of biological origin, such as bacteria, pollen, fungi, and viruses as well as their by-products or toxins, such as Mycotoxins and Endotoxins. Airborne contaminants of biological origin can produce infectious and inflammatory diseases in exposed individuals, such as Tuberculosis, Legionella, Anthrax, Q Fever, and Inflammatory Diseases like Chronic Bronchitis, Asthma, and Conjunctivitis.

Most building related complaints among workers arise from diverse symptoms as a result of exposure to physical and biological agents in buildings. A majority of health complaints in buildings with problems are related to mucous membrane discomfort (i.e., eye, nose, and throat irritation) headache, and fatigue. Mold Spores are known causative agents of these problems.

Mold spores can be found anywhere, inside and outside and they can grow effectively on almost any organic substance, such as wood, paper, carpet, food and insulation, as long as moisture and oxygen are present. Mold gradually destroys these things that it grows on. In some cases indoor mold growth may not be visible or obvious. Mold spores have been found behind dry wall, wall paper, wood paneling, above ceiling tiles, and under carpets and carpet pads. Mold growth has also been known to occur in pipe chases, utility tunnels, near air handling units, on walls behind furniture, as well as underneath roofing material. It is impossible to completely eliminate mold from an indoor environment, but it is possible to control its growth by controlling the level of moisture. The most important reason to control mold growth is the potential health concerns that are associated with airborne mold spores.

Airborne molds and fungi (bioaerosols) are often associated with respiratory ailments. Some species are irritants of the respiratory system and are commonly found in indoor and outdoor environments.

The growth of fungi is influenced by several environmental factors, including light, temperature, nutrients, and most importantly, water. Almost any carbon-containing material, (abundant in both indoor and outdoor environments) can provide adequate nutrients for fungal growth. The introduction of water is the single most important cause of fungi contamination. Keeping an indoor environment dry can essentially prevent fungal growth.


FUNGUS MOST LIKELY TO CAUSE HEALTH PROBLEMS

The most common Mold spore causing health problems is Penicillium/Aspergillus. These contaminants can come in the form of invasive infections, colonizations, toxicoses, or allergies. They are opportunistic invaders, infecting various sites in individuals with lowered resistance to diseases. These Mold Spores have also been known to cause inflammation of the cornea, external ear, respiratory, and urinary tract infections. Some strains have even been known to produce mycotoxins.

A dangerous fungal by-product of Penicillium/Aspergillus is Cladosporium. Cladosporium is a slow-growing fungus that is very sensitive to any kind of disruption. This can allow it to become airborne very easy. It is very common in dead and decaying plants, and therefore it is the fungus that is most commonly found in the outdoor environment. It is a common cause of extrinsic asthma and hay fever. Cladosporium is often found to be a causative agent of skin lesions, sinusitis, and pulmonary infections.

Chaetomium is frequently isolated from plant debris, soil, wood and straw-like materials, as well as air. Indoors, it is found on damp sheetrock and paper products in water damaged buildings.

Chaetomium is reported to be allergenic, and rarely causes toxic diseases in immunosuppressed people. However, it is considered an agent of peritonitis (abdominal disorder), and cutaneous lesions.

Stachybotrys, or the “black mold”, is the most debated fungus today. It grows on moist or water damaged building materials with a high cellulose and low nitrogen content, such as fireboard, gypsum board, paper, ceiling tiles, wood, insulation, and dust. It requires water or excessive moisture for days or weeks to grow. Excessive indoor humidity can be a catalyst in the development of Stachybotrys.

Due to its wet, slimy growth characteristics, it is unusual for spores to become aerosolized, therefore it is readily identifiable on tape lift samples. However, when colonies of this fungus become dehydrated, there is an increased risk for air dispersion, and spores can then be detected through air sampling techniques.

Extreme caution should be exercised when levels of this organism are amplified, as it has been known to produce mycotoxins that can irritate skin and mucous membranes. Exposure can occur through inhalation, ingestion or skin exposure when the fungus becomes embedded in the carpets or walls. Because Stachybotrys spores are very small, some may be drawn into the lungs when airborne spores are inhaled.

The health effects of Stachybotrys chartarum (greenish black fungus) were first noted as diseases in Russian and Eastern European farm animals that ate moldy hay. The first reported human effects were seen in agricultural workers who handled the moldy straw or hay that was affecting the farm animals. Also, after consuming contaminated cereal grains, people experienced symptoms such as burning sensations in mouth, nausea, vomiting, diarrhea and abdominal pain.

Individuals with chronic exposure to Stachybotrys have reported cold and flu-like symptoms, such as sore throats, headaches, fatigue, runny nose and diarrhea. Individuals with chronic respiratory disease may experience trouble breathing, and those with deficient immune systems may be at risk for infection. The actual affect of Stachybotrys along with human health has yet to be defined, and is currently the subject of toxin research.

Due to the fact that it is abundant in the natural environment and is one of the most common fungi worldwide, Alternaria is considered another important fungal allergen. It is commonly found in soil, seeds and plants, but specimen of Alternaria are often found growing on carpets, textiles, in house dust, on damp areas around showers and windows frames, and anywhere condensation occurs. It is commonly found in water-damaged buildings, especially on building materials that contain cellulose, such as drywall sheets. Alternaria is a dry spore and is readily found in air samples as well as on tape lift samples. It may be resistant to fungicide.

Alternaria produces large spores having sizes between 20-200 microns in length and 7-18 microns in width, suggesting that the spores from these fungi are deposited in the nose, mouth, and upper respiratory tract. It may be related to what is commonly known as bakers’ asthma. Also, it has been associated with hypersensitivity pneumonitis, sinusitis, deratomycosis, onychomycosis (nail infection), subcutaneous phaeohyphomycosis, and invasive infection.

Developing an investigation strategy is crucial to air sampling of Bioaerosols. A majority of potentially hazardous Bioaerosol situations arise from an increase of moisture in a building. Should a situation like this occur it becomes important to locate, isolate, and halt whatever the source of moisture may be. These areas then need to be cleaned. Clean up may consist of, but not be limited to: drying, wiping down, and vacuuming with a High Efficiency Particulate Air (HEPA) filtered vacuum.

While walking through a building all areas that may have been affected from an increase in moisture will be the optimal target areas to perform air testing. It is important to note that a visual evaluation may not always reveal serious mold contamination. Therefore, it is often time important for air sampling to be performed.



Acremonium

(Acremonium Conidiophores)

The Acremonium genus, formerly known as Cephalosporium, has about 100 different species, most of which are isolated from soil, hay and organic matter. The spores are slow growing, beginning as compact and moist, and then becoming powdery. There is widespread growth indoors when conditions are extremely wet, and it is often found to be growing with Stachybotrys.

Acremonium is reported to be allergenic, and an opportunistic pathogen that has the ability to cause infection of the nail and cornea.

Arthrinium

(Drawing of several species of Arthrinium)

Arthrinium spores are dark brown and usually occur in grape-like masses on white woolly colonies. The spores are flattened and have a colorless line at the edge. When germinating they break along the line in the manner of a clamshell. In some species the filaments have dark cross-walls. It is commonly found on dead plants, especially grasses and hedges, and is often isolated from air near grassy places in the autumn.

Arthrinium should be considered an allergen. This fungus has also been documented in various subcutaneous infections. However, no toxic related diseases have been discovered.

Agrocybe

Agrocybe sp.

Agrocybe is a wood rotting fungus that is usually found outdoors, in the form of a mushroom, along wood chip paths and bark mulch. It can be eaten, however, it is not recommended. Agrocybe is not a big concern when measuring indoor air quality.

Alternaria

(Alternaria Conidiophores)

Alternaria is composed of dark brown spores that are borne in simple or branched chains. Colonies are fast growing, and appear to the naked eye in black, olive green or gray hues. There are 44 species of Alternaria, which are mostly plant parasites, and are therefore commonly found in decaying plant materials. However, Alternaria is a common saprophyte found in decaying wood, food, and some outdoor air. It is also found in house dust, carpets, textiles, damp areas around showers and window frames, and anywhere condensation occurs.

Due to the fact that Alternaria is abundant in the natural environment and is one of the most common fungi worldwide, it is considered an important fungal allergen. It is a known, but uncommon, cause of asthma and other respiratory ailments, as well as mycotic keratitis (inflammation of the eye) and phaeohyphomycosis (infection of the sinuses). They have also emerged as opportunistic pathogens in individuals with immunosuppressive conditions.

Arthospores

(Arthrospore Conidiophores)

Arthrospores are a type of fungus spore composed of fragments of hyphae (what make up fungi).

Their presence would indicate the presence of various other fungi.

Aspergillus

(Aspergillus Culture)

There are about 200 species in the Aspergillus genus; about 20 of them are known causative agents of human disease. Aspergillus is commonly found in soil, compost piles, plant debris, water damaged buildings, a wide range of substrates, and house dust. It is one of the most common contaminants found in indoor air (some species prefer drier conditions), as well as in water-damaged buildings.

Aspergillus is usually non-pathogenic, as most people are naturally immune to diseases associated with it, but can become opportunistic in the respiratory tract. It is associated with many respiratory ailments, and it often agitates sinuses. Aspergillosis, a result of prolonged exposure to Aspergillus, causes infections in most human organs including the lung, nasal sinuses, as well as the skin.

BIPOLARIS

(Bipolaris Conidiophores)

Bipolaris is a common saprophyte, and a subtropical and tropical plant pathogen. It is commonly found on dead or dying plant material, and its colonies are moderately fast growing.

Several of its 45 species are documented in human infection. The Bipolaris spores are large and are often times deposited in the upper respiratory tract. Clinical manifestations include mycotic keratitis (inflammation of the eye), subcutaneous phaeohyphomycosis (skin lesions), sinusitis, peritonitis (abdominal disorder), and some cerebral and scattered infections.

Chaetomium

(Ascospores of Chaetomium species and Chaetomium Culture)

Chaetomium is frequently isolated from plant debris, soil, wood and straw-like materials, as well as air. Indoors, it is found on damp sheetrock and paper products in water damaged buildings.

Chaetomium is reported to be allergenic, and rarely causes toxic diseases in immunosuppressed people. However, it is considered an agent of peritonitis (abdominal disorder), and cutaneous lesions.

Cladosporium

(Cladosporium Culture)

The Cladosporium genus has about 30 different species, and is often times a bi-product of Aspergillus/Penicillium. The spores are slow-growing and very sensitive to any kind of disruption. It is the most frequently found fungus in the outside air and in decaying plants. Cladosporium spores have been found indoors, but usually with less of a concentration, as they may need cycles of light to produce spores. It grows indoors where there is moisture or condensation. Houses with poor ventilation or located in damp environments may have heavy concentrations.

Cladosporium has the ability to sporulate very heavily, and is therefore an important fungal allergen. It is a common cause of extrinsic asthma, and is frequently isolated as a contaminant in the air. Cladosporium is often times found to be a causative agent of skin lesions, sinusitis, and pulmonary infections.

(Cladosporium Conidiophores)

Coprinus

Coprinus micaceus

There are many different species of Coprinus found in the outside environment, and they are all found in mushroom form. They are blackish spores that grow in wet conditions. Coprinus should be treated as an important inhalant allergen.

Curvularia

(Curvularia Conidiophores)

(Curvularia Culture)

Curvularia is a common saprophyte, with fast growing colonies. It has about 35 species, which are usually subtropical and tropical plant parasites. However, it will grow indoors on a number of substrates.

Despite being primarily a plant parasite, three species have been found to cause human infections, such as corneal infections and various infections in immune compromised people.

Epicoccum

(Epicoccum Culture)

The Epicoccum genus is made of fast growing colonies, usually with a yellow/orange pigmentation. The spores are found in plants, soils, grains, textiles, and paper products.

Epicoccum is a known allergen, and is occasionally isolated as a contaminant from clinical specimens, such as skin.

(Epicoccum Conidiophores)

Ganoderma

Ganoderma applanatum

Ganoderma typically grows on dead or dying hardwoods. Ganoderma spores are known to stimulate and enhance immunity, and prevent and suppress cancer. It is considered a powerful natural healing herb in Chinese medicine. For many years it was used to ward off hepatitis, bronchitis, asthma, insomnia and nephritis (kidney condition).

Hyphae

All growing fungi have branched filaments called Hyphae. Hyphae are linear chains of tubular structures, and eventually produce fruiting bodies that contain reproductive spores.

Some mycotoxins are associated with Hyphae, and because it is what gives mold its structure, and therefore its presence is a strong indication that there are mold spores present in the air.

Paecilomyces

(Paecilomyces Conidiophores)

Paecilomyces is a saprophyte commonly found among dead plants and compost. It is a fast growing colony usually found in warm climates and arid regions. However, it has been isolated from jute fibers, paper, PVC and timber.

Paecilomyces is related to the genus Penicillium (an allergenic fungi), but is rarely a human pathogen. However, some species have been known to cause mycotic keratitis (inflammation of the eye) and of hyalohyphomycosis (skin lesions) in immune compromised individuals.

Penicillium

(Penicillium Culture)

Penicillium spores are usually fast growing, and dense. They are brush-like spear-bearing structures found in shades of green and sometimes white. It is one of the most common household molds, and a frequent food contaminant. It can be found in house dust, carpets, wallpaper, wallpaper glue, decaying fabrics, behind paint and in interior fiberglass duct insulation. It is commonly found in water-damaged buildings. Penicillium is allergenic, and a common cause of extrinsic asthma. Some species are known as potential mycotoxin producers.

(Penicillium Conidiophores)

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(Penicillium Conidiophores)

(Penicillium on orange)

Pithomyces

(Pithomyces Conidiophores)

Pithomyces colonies are fast growing, and usually become visible because of their dark pigment. The genus contains 15 species, and is found on litter, dead leaves and soil. It rarely grows indoors but it can grow on paper. Pithomyces is not a known human pathogen, but is often involved with facial eczema of sheep.

Stachybotrys

(Penicillium culture and Penicillium Conidiophores)

Stachybotrys lives and grows extremely well on water damaged building materials cellulose rich materials such as sheet rock, paper, ceiling tiles, wood, insulation backing and wallpaper. It requires water or moisture for days or weeks to grow.

Excessive indoor humidity can be a catalyst in the development of Stachybotrys. Due to its wet, slimy growth characteristics, it is unusual for spores to become aerosolized; therefore it is readily identifiable on tape lift samples. However, when colonies of this fungus become dehydrated, there is increased risk for air dispersion, and can then be detected through air sampling techniques.

Extreme caution should be exercised when levels of this organism are amplified, as it has been known to produce mycotoxins that can irritate skin and mucous membranes.

Exposure can occur through inhalation, ingestion or skin exposure when the fungus becomes embedded in the carpets or walls. Several strains of this fungus produce a toxin that is poisonous by inhalation. Individuals with chronic exposure to Stachybotrys have reported cold and flu-like symptoms, such as sore throats, headaches, fatigue and diarrhea. Individuals with chronic respiratory disease may experience trouble breathing, and those with deficient immune systems may be at risk for infection. The actual affect of Stachybotrys along with human health has yet to be defined, and is currently the subject of toxin research.

Stemphylium

(Stemphylium Conidiophores)

Stemphylium colonies are rapid growing, and are brown, green or black in color. Growth indoors is rare.

Stemphylium are plant pathogens and are rarely seen as causative agents of human infection. They are, however, considered to be allergenic.

Ulocladium

(Ulocladium culture)

Ulocladium colonies are fast growing and brown-black or grayish in color. The spores are commonly found on dead plants, rotten wood, paper, textiles, and cellulose materials. This mold frequently occurs in air and dust samples, and is also found in water-damaged buildings.

Although Ulocladium can be very allergenic, the spores are rarely seen as pathogenic in humans.

(Ulocladium Conidiophores)


2 comments:

Vinay Singh said...

We've seen a few versions of jelly and cake mould lights before, but I think what I like about these is that they are all tin. Most I've seen in the past have been from the coloured plastic type.
Industrial Hygiene

Unknown said...

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