Effect of Chlorine Dioxide Gas on Fungi and Mycotoxins Associated with Sick Building Syndrome

Abstract

The growth of indoor molds and their resulting products (e.g., spores and mycotoxins) can present health hazards for human beings. The efficacy of chlorine dioxide gas as a fumigation treatment for inactivating sick building syndrome-related fungi and their mycotoxins was evaluated. Filter papers (15 per organism) featuring growth of Stachybotrys chartarum, Chaetomium globosum, Penicillium chrysogenum, and Cladosporium cladosporioides were placed in gas chambers containing chlorine dioxide gas at either 500 or 1,000 ppm for 24 h. C. globosum was exposed to the gas both as colonies and as ascospores without asci and perithecia. After treatment, all organisms were tested for colony growth using an agar plating technique. Colonies of S. chartarum were also tested for toxicity using a yeast toxicity assay with a high specificity for trichothecene mycotoxins. Results showed that chlorine dioxide gas at both concentrations completely inactivated all organisms except for C. globosum colonies which were inactivated an average of 89%. More than 99% of ascospores of C. globosum were nonculturable. For all ascospore counts, mean test readings were lower than the controls (P < 0.001), indicating that some ascospores may also have been destroyed. Colonies of S. chartarum were still toxic after treatment. These data show that chlorine dioxide gas can be effective to a degree as a fumigant for the inactivation of certain fungal colonies, that the perithecia of C. globosum can play a slightly protective role for the ascospores and that S. chartarum, while affected by the fumigation treatment, still remains toxic.Sick building syndrome (SBS) is a broad term for a range of human health symptoms associated with poor indoor air quality. While poor indoor air quality can be related to a number of issues, the one that has received the most attention in the last 5 to 10 years has been the effects of airborne fungi and their products (2, 6, 12). It has been acknowledged that damp and moldy structures are potentially harmful to the occupants (16). Therefore, from a human health standpoint, it is recommended that the conditions that allowed for fungal proliferation inside human occupied structures be addressed and corrected and that existing fungal growth be removed or treated from any affected substrates. However, a problem is the detection of hidden mold growth sites. Invasive investigations can assist in this regard, but these investigations can be costly to effect and there is also the possibility that some growth sites can be overlooked. It is possible that gaseous fungicides may be able to circumvent this problem because the gas can penetrate into crevices, wall cavities and other hard to access areas, thus treating the inaccessible mold colonies. The contents inside a contaminated structure may also be able to be sterilized (10) using this technique as well. A biocide, chlorine dioxide, has been previously been used in a gaseous form for bacterial decontamination (1, 9). It has been also shown to have a degree of fungicidal activi...

Indoor Fungal Populations Inhabiting Cement Structures - Remedial Measures

“…The other treatments which include gas treatment with ClO 2, antifungal agents including uv radiation are successful in inactivating mold and bacterial colonies. But, the other side effects such as corrosive properties (chlorine dioxide gas) require care to avoid degradation of the contents as well as the components of the structure [11] and respiratory impacts Aged buildings during rainy season, buildings or houses affected with seepage or water leakages often create favorable conditions for the fungal infestations on the wooden cupboards, furniture and cement walls. Indoor fungal infestations can be controlled by spraying cheap and household materials available.…”

“…Gaseous fungicides such as ClO 2 is a strong oxidant, capable of circumvent the problem of overlooking of growth sites ,penetrate into crevices, wall cavities and other hard to access areas and treats the inaccessible mold colonies. It is also capable of sterilizing the contents inside a contaminated structure [11]. The fungicides have negative impact on ecosystem and food chain, hence ecofriendly measures are of importance…”

Protective effect of low-concentration chlorine dioxide gas against influenza A virus infection

“…ClO 2 is a free radical, owing to one unpaired electron in its molecular orbital (ClO 2 : ) (Lynch et al, 1997). Possibly due to its strong oxidizing activity (Moran et al, 1953;Fukayama et al, 1986), when dissolved in water, ClO 2 has potent antimicrobial activity against bacteria, fungi, protozoa and viruses (Taylor & Butler, 1982;Harakeh et al, 1988;Chen & Vaughn, 1990;Foschino et al, 1998;Eleraky et al, 2002;Schwartz et al, 2003;Sivaganesan et al, 2003;Li et al, 2004;Loret et al, 2005;Sy et al, 2005;Wilson et al, 2005;Okull et al, 2006;Simonet & Gantzer, 2006). However, the antimicrobial activities of gas-phase ClO 2 have not been well studied.…”

Development of chlorine dioxide gas generation chamber to prevent spoilage of eggs

“…The potential of chlorine dioxide for killing oral bacteria has been widely studied, as clinical and laboratory investigations have demonstrated that stabilized chlorine dioxide oral rinse reduces bacteria numbers in the mouth, essentially eliminating oral malodor, as well as signs of gum disease (Drake and Villhauer, 2011). A study carried out by Wilson et al suggested that chlorine dioxide treatment can inhibit growth of fungi and molds which are associated with many human diseases including sick building syndrome (SBS) (Wilson et al, 2005).…”