IAQA - White Paper Archives

IAQA 18th Annual Meeting & Indoor Environment and Energy Expo (IE3) The views and opinions herein are those of the volunteer authors and may not reflect the views and opinions of IAQA. The information is offered in good faith and believed to be reliable but it is provided without warranty, expressed or implied, as to the merchantability, fitness for a particular purpose or any other matter. Study Between Moldiness and Endotoxin Levels in Residential Buildings By Jason Dobranic, Ph.D. EMSL Analytical, Inc. Endotoxin exposure continues to be studied and investigated in relation to indoor environmental quality and the health of building occupants. A significant number of IEQ investigations focus on mold exposure and do not routinely sample for endotoxin, although researchers continue to find links to exposure and health effects.. Therefore in this study we wanted to see if there was any relationship to moldiness of residential homes to endotoxin levels. The hypothesis being that conditions conducive to mold growth will likewise produce higher endotoxin levels; in other words moldiness and endotoxin levels are positively correlated. What is Endotoxin? Bacteria can be discriminated into two major groups depending on their cell wall make-up; Gram positive and Gram negative. In 1884, a Danish doctor named, Hans Christian Gram, accidentally stumbled upon a method that stained bacteria either purple (Gram positive) or red (Gram negative). This is becauseGram negative bacterial cell walls consist of an outer lipopolysaccharide layer (LPS) followed by a small peptidoglycan layer,while the Gram positive bacteria have primarily a thick peptidoglycan layer forming their cell wall. It is the LPS layer of Gram negative bacteria that once entered into the body is called endotoxin. Endotoxin is recalcitrant in the environment and heat-stable. Simply killing the bacteria does not remove the endotoxin concern. Researchers have found that not all endotoxin is the same. What they found was that the LPS of E. coli and Salmonella enteritis was about four times more potent than that of Klebsiellapneumoniae and Pseudomonas aeruginosa. Endotoxin levels have been studied from various environments and found to be elevated in sewage treatment plants, swine operations, cotton textile mills, poultry houses, saunas, hemp processing areas, potato sorting areas, cigar and cigarette manufacturing, grain handling, manure handling, and water damaged buildings. As one would expect, anywhere that there is a likelihood of bacterial proliferation there is a chance of endotoxin. Particularly in places with the presence of fecal matter since Gram negative bacteria are predominant in this feces. Studies of buildings classified as having "sick building syndrome" were found to have six to seven times higher endotoxin levels than control buildings (254 ng/m 3 vs 46 ng/m 3 ). Endotoxin exposure from the environment typically comes from breathing in contaminated dust and debris. Health effects are primarily airway inflammation resulting in wheezing and coughing. Endotoxin is pyrogenic meaning it can produce fever and chills. I have heard this many times anecdotally regarding a plumber having fevers the evening after working on a job fixing leaking pipes. Endotoxin has been studied in drinking water and found there is likely no measureable effect from shower exposures but that exposure from humidifiers was significant; primarily with ultrasonic and impeller designs.In fact, endotoxin has been found to be one of the primary causes of humidifier fever with >1,000 EU/mL of endotoxin capable of inducing chills and fever. Lack of cleaning results in bacterial blooms that get spewed out with the humidified air. Non- environmental exposures are also possible. Endotoxin levels are closely measured and tested in pharmaceutical injectables, intravenous drugs/solutions, surgical tubing, dialysis waters, etc., because direct introduction from these products would also have significant health effects. Within the body, endotoxin will cause an increase in white blood cell and antibodies and following endotoxin exposure markers can be found in the blood. An ELISA test called EndoCab Human can be used to test for levels of anti-endotoxin core antibodies circulating in the blood. EndoCab Human can even be used to indicate endotoxin exposure when endotoxin cannot be measure in the environment. There has also been an association between endotoxin and increased severity of child and adult asthma as well as causing an increase in susceptibility to environmental allergens. Other research has interestingly shown that exposure to endotoxin

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