Estimation of endotoxin inhalation from shower and humidifier exposure reveals potential risk to human health

Abstract

This paper investigates potential exposure to endotoxin in drinking water through the inhalation of aerosols generated by showers and humidifiers. Adverse health effects attributable to the inhalation of airborne endotoxin in various occupational settings are summarized, as are controlled laboratory inhalation studies. Data from investigations estimating aerosolization of particulate matter by showers and humidifiers provide a basis for similar analyses with endotoxin, which like minerals in water, is nonvolatile. A theoretical assessment of the inhalation of aerosolized endotoxin showed that while the likelihood of an acute response while showering is minimal, the same is not true for humidifiers. Ultrasonic and impeller (cool mist) humidifiers efficiently produce large numbers of respirable particles. It is predicted that airway inflammation can occur if humidifier reservoirs are filled with tap water, sometimes even at typical drinkingwater distribution-system endotoxin concentrations. Higher endotoxin levels occasionally found in drinking water (.1,000 EU/ml) are very likely to induce symptoms such as chills and fever if used as humidifier feed water. While it is unlikely that treated drinking water would contain extremely high endotoxin levels occasionally observed in cyanobacterial blooms (.35,000 EU/ml), the potential for serious acute health consequences exist if used in humidifiers.

Pilot study of sources and concentrations of size-resolved airborne particles in a neonatal intensive care unit

“…15 According to specifications provided by the manufacturer, incubator humidification is provided through a steam-generation process. While ultrasonic and impeller humidifiers are known to generate particles, steam humidification has not been shown in previous studies to be associated with significant increases in indoor airborne particle mass concentrations [20][21][22].…”

“…The biggest size group is displayed as the sum of the two largest size channels of the optical particle counter with an adopted overall upper diameter limit of 15 µm. 20 …”

Adsorption of Endotoxin from Aqueous Solution Using Bone Char

“…Also, it is known that endotoxin may act as a co-allergen, facilitating sensitization to other allergens, or they may increase the severity of allergic disease (Szymanska 2005). The potential pathways of water-associated endotoxin exposure in humans include direct introduction in to the blood stream via semi permeable dialysis membranes and inhalation of moisture-saturated air in showers, swimming pools, hot tubs, saunas, and dental offices (Anderson et al 2007). Exposure to endotoxins by drinking water used for preparation or dilution of solutions for intravenous injection or dialysis may be even more serious (Castor et al 2005).…”

“…Exposure to endotoxins by drinking water used for preparation or dilution of solutions for intravenous injection or dialysis may be even more serious (Castor et al 2005). Several other settings for endotoxin exposure include sawmills, paper recycling plants (repulping and deinking), fiberglass manufacturing, animal handling, cotton/textile milling, hemp processing and potato sorting (Sarantila et al 2001;Anderson et al 2007). Although several exposure routes and the adverse effects of this pollutant have been identified, unfortunately there is only limited information available on untreated surface water, ground water, and drinking water endotoxin concentrations.…”

Determination of ATP-activity as a useful tool for monitoring microbial load in aqueous humidifier samples

“…Furthermore, in non-occupational settings, microbial contaminations of ultrasonic misting fountains at home have been shown to induce hypersensitivity pneumonitis (HP)-like symptoms (Koschel et al, 2005). Water contaminated with endotoxin, molds and other components have been shown to be associated with toxic, infectious and irritative reactions (Anderson et al, 2007;Raulf-Heimsoth et al, 2010;Ohnishi et al, 2002). Allergic reactions have also been reported Sander et al, 2012).…”