Effect of Gaseous Chlorine Dioxide on Indoor Microbial Contaminants

Abstract

Traditional and modern techniques for bioaerosol enumeration were used to evaluate the relative efficiency of gaseous chlorine dioxide (ClO 2 ) in reducing the indoor microbial contamination under field and laboratory conditions. The field study was performed in a highly microbially contaminated house, which had had an undetected roof leak for an extended period of time and exhibited large areas of visible microbial growth. Air concentrations of culturable fungi and bacteria, total fungi determined by microscopic count and polymerase chain reaction (PCR) assays, endotoxin, and (133)-␤-D-glucan were determined before and after the house was tented and treated with ClO 2. The laboratory study was designed to evaluate the efficiency of ClO 2 treatment against known concentrations of spores of Aspergillus versicolor and Stachybotrys chartarum on filter paper (surrogate for surface treatment). These species are commonly found in damp indoor environments and were detected in the field study. Upon analysis of the environmental data from the treated house, it was found that the culturable bacteria and fungi as well as total count of fungi (as determined by microscopic count and PCR) were decreased at least 85% after the ClO 2 application. However, microscopic analyses of tape samples collected from surfaces after treatment showed that the fungal structures were still present on surfaces. There was no statistically significant change in airborne endotoxin and (133)-␤-D-glucan concentration in the field study. The laboratory study supported these results and showed a nonsignificant increase in the concentration of (133)-␤-D-glucan after ClO 2 treatment.

Occupational Exposure to Aflatoxin B1in Swine Production and Possible Contamination Sources

“…Nevertheless, the prevalent genera noted are common in several studies (Jo and Kang, 2005;Duchaine et al, 2000). All seven swine farms showed high counts of A. versicolor in air and on surfaces, with surfaces less susceptible to variation to fungal concentration than air, since it is harder to deactivate spores on surfaces than in the air (Burton et al, 2008). This may account for less variation regarding fungal contamination in this setting.…”

Fungal Contamination Assessment in Portuguese Elderly Care Centers

“…Real-time PCR did not detect the presence of A. fumigatus complex, probably due to the presence of environmental contaminants present indoors that inhibit PCR analyses, which may result in false-negative samples (Burton et al, 2008). It is also possible that the number of microorganisms present in the environment was below the threshold of amplification by real-time PCR.…”

Chlorine Dioxide for Bleaching, Industrial Applications and Water Treatment

“…It was employed as the principal reagent in the decontamination of buildings in the USA after the 2001 anthrax attacks [39]. After the disaster of Hurricane Katrina in New Orleans, Louisiana and the surrounding Gulf Coast, chlorine dioxide was used to eradicate dangerous mould from houses inundated by water from massive flooding [40,41]. Chlorine dioxide has been successfully used as an oxidant for phenol destruction in waste water streams, control of zebra and quagga mussels in water intakes and for odour control in the air scrubbers of animal byproduct plants.…”